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Sample records for 76ge neutrinoless double-beta

  1. GERDA - a new neutrinoless double beta experiment using 76Ge

    NASA Astrophysics Data System (ADS)

    Meierhofer, G.; GERDA Collaboration

    2011-09-01

    The search for neutrinoless double beta decay (0νßß) has been a very active field for the last decades. While double beta decay has been observed, 0νßß decay still waits for its experimental proof. The GErmanium Detector Array (GERDA) uses 76Ge, an ideal candidate as it is acting as source and detector simultaneously. Germanium detectors, isotopically enriched in 76Ge are submerged directly into an ultra pure cryo liquid, which serves as coolant and radiation shield. This concept will allow to reduce the background by up to two orders of magnitude with respect to earlier experiments. GERDA has been constructed in hall A of the underground laboratory LNGS of the INFN in Italy. The experiment started recently with a test run.

  2. Limit on Neutrinoless Double Beta Decay of 76Ge by GERDA

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Heider, M. Barabè; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Machado, A. A.; Macolino, C.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; Shaughnessy, C. O.'.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    The Gerda experiment at the Laboratori Nazionali del Gran Sasso in Italy uses germanium detectors made from material with an enriched 76Ge isotope fraction to search for neutrinoless double beta decay of this nucleus. Applying a blind analysis we find no signal after an exposure of 21.6 kg·yr and a background of about 0.01 cts/(keV·kg·yr). A half-life limit of Tov1/2> 2.1 · 1025 yr (90% C.L.) is extracted. The previous claim of a signal for 76Ge is excluded with 99% probability in a model independent way.

  3. Results on neutrinoless double beta decay of 76Ge from GERDA Phase I

    NASA Astrophysics Data System (ADS)

    Palioselitis, Dimitrios; GERDA Collaboration

    2015-05-01

    The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta (0νββ) decay of 76Ge by operating bare germanium diodes in liquid argon. GERDA is located at the Gran Sasso National Laboratory (LNGS) in Italy. During Phase I, a total exposure of 21.6 kg yrand a background index of 0.01 cts/(keVkg yr) were reached. No signal was observed and a lower limit of T0ν1/2 > 2.1 · 1025 yr(90% C.L.) is derived for the half life of the 0νββ decay of 76Ge.

  4. The Majorana Demonstrator: A Search for Neutrinoless Double-beta Decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Xu, W.; Abgrall, N.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Efremenko, Yu; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

    2015-05-01

    Neutrinoless double-beta (0νββ) decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The Majorana Collaboration is constructing the MAJORANA DEMONSTRATOR, with a total of 40-kg Germanium detectors, to search for the 0νββ decay of 76Ge and to demonstrate a background rate at or below 3 counts/(ROI·t·y) in the 4 keV region of interest (ROI) around the 2039 keV Q-value for 76Ge 0νββ decay. In this paper, we discuss the physics of neutrinoless double beta decay and then focus on the MAJORANA DEMONSTRATOR, including its design and approach to achieve ultra-low backgrounds and the status of the experiment.

  5. Results on neutrinoless double beta decay of 76Ge from the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Palioselitis, Dimitrios

    2015-05-01

    The Germanium Detector Array (GERDA) experiment is searching for neutrinoless double beta (0νββ) decay of 76Ge, a lepton number violating nuclear process predicted by extensions of the Standard Model. GERDA is an array of bare germanium diodes immersed in liquid argon located at the Gran Sasso National Laboratory (LNGS) in Italy. The results of the GERDA Phase I data taking with a total exposure of 21.6 kg yr and a background index of 0.01 cts/(keV kg yr) are presented in this paper. No signal was observed and a lower limit of T1/20ν > 2.1×1025 yr (90% C.L.) was derived for the half-life of the 0νββ decay of 76Ge. Phase II of the experiment aims to reduce the background around the region of interest by a factor of ten.

  6. Search for Neutrinoless Double Beta Decay of 76Ge with the GERmanium Detector Array "gerda"

    NASA Astrophysics Data System (ADS)

    Garfagnini, Alberto

    2011-10-01

    The study of neutrinoless double beta decay (DBD) is the only presently known approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of neutrinoless DBD would not only establish the Majorana nature of the neutrino but also represent a determination of its effective mass if the nuclear matrix element is given. So far, the most sensitive results have been obtained with 76Ge, and the group of Klapdor-Kleingrothaus has made a claim of discovery. Future experiments have to reduce radioactive backgrounds to increase the sensitivity. GERDA is a new DBD experiment which is currently under construction in the INFN Gran Sasso National Laboratory, Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in 76Ge - in high purity liquid argon supplemented by a water shield. The aim of GERDA is to scrutinize the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments, increasing the sensitive mass and reaching an exposure of 100 kg yr. The paper will discuss design, physics reach, and status of construction of GERDA.

  7. The 76Ge(n,p)76Ga reaction and its relevance to searches for the neutrino-less double-beta decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Tornow, W.; Bhike, Megha; Fallin, B.; Krishichayan, Fnu

    2015-10-01

    The 76Ge(n,p)76Ga reaction and the subsequent β decay of 76Ga to 76Ge has been used to excite the 3951.9 keV state of 76Ge, which decays by emission of a 2040.7 keV γ ray. Using HPGe detectors, the associated pulse-height signal may be undistinguishable from the potential signal produced in neutrino-less double-beta decay of 76Ge with its Q-value of 2039.0 keV. In the neutron energy range between 10 and 20 MeV the production cross section of the 2040.7 keV γ ray is approximately 0.1 mb. In the same experiment γ rays of energy 2037.9 keV resulting from the 76Ge(n, γ)77Ge reaction were clearly observed. Adding the 76Ge(n,n' γ)76Ge reaction, which also produces the 2040.7 keV γ ray with a cross section value of the order of 0.1 mb clearly shows that great care has to be taken to eliminate neutron-induced backgrounds in searches for neutrino-less double-beta decay of 76Ge. This work was supported by the U.S. DOE under Grant NO. DE-FG02-97ER41033.

  8. The Majorana Demonstrator: Progress towards showing the feasibility of a 76Ge neutrinoless double-beta decay experiment

    SciTech Connect

    Finnerty, P.; Aguayo, Estanislao; Amman, M.; Avignone, Frank T.; Barabash, Alexander S.; Barton, P. J.; Beene, Jim; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, P. J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Fraenkle, Florian; Galindo-Uribarri, A.; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Looker, Q.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Perumpilly, Gopakumar; Phillips, David; Poon, Alan; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-03-24

    The Majorana Demonstrator will search for the neutrinoless double-beta decay (0*) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a lowbackground environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 counts tonne -1 year-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0; and performing a direct search for lightWIMPs (3-10 GeV/c2).

  9. Critical view to ``IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments''

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, H. V.; Dietz, A.; Krivosheina, I. V.

    2004-10-01

    Recently, a paper entitled “The IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments” has been published [

    Phys. Rev. D 65, 092007 (2002)PRVDAQ0556-282110.1103/PhysRevD.65.092007
    ]. In view of the recently reported evidence for neutrinoless double-beta decay [
    Mod. Phys. Lett. A 16, 2409 (2001).MPLAEQ0217-732310.1142/S0217732301005825
    ;
    Found. Phys.FNDPA40015-9018 31, 1181 (2002)
    ;
    Phys. Lett. BPYLBAJ0370-2693 586, 198 (2004).10.1016/j.physletb.2004.02.025
    ], it is particularly unfortunate that the IGEX paper is rather incomplete in its presentation. We would like to point out in this Comment that and why it would be highly desirable to make more details about the experimental conditions and the analysis of IGEX available. We list some of the main points, which require further explanation. We also point to an arithmetic mistake in the analysis of the IGEX data, the consequence of which are too high half-life limits given in that paper.

  10. Inelastic neutron scattering cross sections for 76Ge relevant to background in neutrinoless double-beta decay experiments

    DOE PAGESBeta

    Crider, Ben; Peters, Erin; Allmond, James M; McEllistrem, M; Prados-Estevez, F.; Ross, T.J.; Vanhoy, J.R.; Yates, S.W.

    2015-01-01

    The experimental signature in searches for the neutrinoless double- decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Inelastic scattering reactions with neutrons from muon-induced interactions and ( ,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We have measured the production cross sections for rays from the 76Ge(n,n ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the cross sectionsmore » of a previously known 2040.7-keV ray from the 3952-keV level in 76 Ge are rather small, we find that a larger contribution arises from a 2037.5-keV ray which is attributed to a newly identified level at 3147 keV in 76Ge. A third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double- decay searches is more complex than was previously thought.« less

  11. The Majorana Demonstrator: Progress towards showing the feasibility of a tonne-scale 76Ge neutrinoless double-beta decay experiment

    NASA Astrophysics Data System (ADS)

    Finnerty, P.; Aguayo, E.; Amman, M.; Avignone, F. T., Iii; Barabash, A. S.; Barton, P. J.; Beene, J. R.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Luke, P. N.; MacMullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G., Ii; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

    2014-03-01

    The Majorana Demonstrator will search for the neutrinoless double-beta decay (0vββ) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a low-background environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 t-1 y-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0vββ [1]; and performing a direct search for light WIMPs (3-10 GeV/c2).

  12. Neutrino mass ordering in future neutrinoless double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Zhang, Jue

    2016-06-01

    Motivated by recent intensive experimental efforts on searching for neutrinoless double beta decays, we present a detailed quantitative analysis on the prospect of resolving neutrino mass ordering in the next generation 76Ge-type experiments.

  13. Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Cremonesi, Oliviero

    2016-05-01

    After more than 3/4 of century from its proposal, Neutrinoless Double Beta Decay (NLDBD) is still missing observation and continues to represent the only practical method for investigating the Dirac/Majorana nature of neutrinos. In case neutrinos would be Majorana particles, NLDBD would provide unique informations on their properties (absolute mass scale and Majorana phases). Boosted by the discovery of neutrino oscillations, a number of experiments with improved sensitivity have been proposed in the past decade. Some of them have recently started operation and others are ready to start. They will push the experimental sensitivity on the decay halflife beyond 1026 year, starting to analyze the region of the inverted mass hierarchy. The status and perspectives of the ongoing experimental effort are reviewed. Uncertainties coming from the calculation othe decay nuclear matrix elements (NME) as well as the recently suggested possibility of a relevant quenching of the axial coupling constant are also discussed.

  14. Sterile neutrinos in neutrinoless double beta decay

    SciTech Connect

    Benes, P.; Faessler, Amand; Simkovic, F.; Kovalenko, S.

    2005-04-01

    We study possible contribution of the Majorana neutrino mass eigenstate {nu}{sub h}, dominated by a sterile neutrino component, to neutrinoless double beta (0{nu}{beta}{beta}) decay. A special emphasis is made on accurate calculation of the corresponding nuclear matrix elements. From the current experimental lower bound on the 0{nu}{beta}{beta}-decay half-life of 76 Ge we derive stringent constraints on the {nu}{sub h}-{nu}{sub e} mixing in a wide region of the values of {nu}{sub h} mass. We discuss cosmological and astrophysical status of {nu}{sub h} in this mass region.

  15. Correlations and the neutrinoless double beta decay

    SciTech Connect

    Menendez, J.; Poves, A.; Caurier, E.; Nowacki, F.

    2009-11-09

    We explore the influence of the deformation on the nuclear matrix elements of the neutrinoless double beta decay (NME), concluding that the difference in deformation -or more generally on the amount of quadrupole correlations- between parent and grand daughter nuclei quenchs strongly the decay. We discuss how varies the nuclear matrix element of {sup 76}Ge decay when the wave functions of the two nuclei involved in the transition are constrained to reproduce the experimental occupancies. In the Interacting Shell Model description the value of the NME is enhanced about 15% compared to previous calculations, whereas in the QRPA the NME's are reduced by 20%-30%, thus, the discrepancies between both approaches diminish.

  16. The Majorana Neutrinoless Double-Beta Decay Program

    NASA Astrophysics Data System (ADS)

    Guiseppe, Vincente

    2014-09-01

    Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The Majorana Collaboration is assembling an array of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, containing 40 kg (30 kg enriched in 76Ge) of Ge detectors, is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota. The initial goals are to demonstrate the required background and scalability of a Ge-based, tonne-scale experiment. The status and potential physics reach of the Majorana Demonstrator experiment will be presented. Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The Majorana Collaboration is assembling an array of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, containing 40 kg (30 kg enriched in 76Ge) of Ge detectors, is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota. The initial goals are to demonstrate the required background and scalability of a Ge-based, tonne-scale experiment. The status and potential physics reach of the Majorana Demonstrator experiment will be presented. We acknowledge support from the Office of Nuclear Physics in the DOE Office of Science, the Particle and Nuclear Astrophysics Program of the National Science Foundation and the Russian Foundation for Basic Research.

  17. The GERDA Neutrinoless Double Beta-Decay Experiment

    SciTech Connect

    Majorovits, Bela A.

    2007-10-12

    Neutrinoless double beta (0{nu}{beta}{beta})-decay is the key process to gain understanding of the nature of neutrinos. The GErmanium Detector Array (GERDA) is designed to search for 0{nu}{beta}{beta}-decay of the isotope {sup 76}Ge. Germanium crystals enriched in {sup 76}Ge, acting as source and detector simultaneously, will be submerged directly into an ultra pure cooling medium that also serves as a radiation shield. This concept will allow for a reduction of the background by up to two orders of magnitudes with respect to earlier experiments.

  18. Predicting neutrinoless double beta decay

    SciTech Connect

    Hirsch, M.; Villanova del Moral, A.; Valle, J.W.F.

    2005-11-01

    We give predictions for the neutrinoless double beta decay rate in a simple variant of the A{sub 4} family symmetry model. We show that there is a lower bound for the {beta}{beta}{sub 0{nu}} amplitude even in the case of normal hierarchical neutrino masses, corresponding to an effective mass parameter vertical bar m{sub ee} vertical bar {>=}0.17{radical}({delta}m{sub ATM}{sup 2}). This result holds both for the CP conserving and CP violating cases. In the latter case we show explicitly that the lower bound on vertical bar m{sub ee} vertical bar is sensitive to the value of the Majorana phase. We conclude therefore that in our scheme, {beta}{beta}{sub 0{nu}} may be accessible to the next generation of high sensitivity experiments.

  19. Majorana neutrino masses and the neutrinoless double-beta decay

    SciTech Connect

    Faessler, A.

    2006-12-15

    Neutrinoless double-beta decay is forbidden in the Standard Model of electroweak and strong interaction but allowed in most Grand Unified Theories (GUTs). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass is neutrinoless double-beta decay allowed. Apart from one claim that the neutrinoless double-beta decay in {sup 76}Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow one to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUTs and the minimal R-parity-violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUTs. For that, one has to assume that the specific mechanism is the leading one for neutrinoless double-beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present work, one discusses the accuracy of the present status of calculating of the nuclear matrix elements and the corresponding limits of GUTs and supersymmetric parameters.

  20. The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

    SciTech Connect

    Schubert, Alexis G.; Aguayo, Estanislao; Avignone, F. T.; Zhang, C.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Leon, Jonathan D.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, Mark; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, Werner; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2012-09-28

    The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge neutrinoless double-beta decay Q-value of 2039 keV.

  1. Optimization of the Transport Shield for Neutrinoless Double Beta-decay Enriched Germanium

    SciTech Connect

    Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Orrell, John L.; Reid, Douglas J.; Fast, James E.

    2012-04-15

    This document presents results of an investigation of the material and geometry choice for the transport shield of germanium, the active detector material used in 76Ge neutrinoless double beta decay searches. The objective of this work is to select the optimal material and geometry to minimize cosmogenic production of radioactive isotopes in the germanium material. The design of such a shield is based on the calculation of the cosmogenic production rate of isotopes that are known to cause interfering backgrounds in 76Ge neutrinoless double beta decay searches.

  2. Searches for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Schwingenheuer, Bernhard

    2012-07-01

    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136Xe. The sensitivities of the different proposals are reviewed.

  3. Sensitivity of CUORE to Neutrinoless Double-Beta Decay

    SciTech Connect

    CUORE; Alessandria, F.; Andreotti, E.; Ardito, R.; Arnaboldi, C.; Avignone III, F. T.; Balata, M.; Bandac, I.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Bloxham, T.; Brofferio, C.; Bryant, A.; Bucci, C.; Cai, X. Z.; Canonica, L.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chott, N.; Clemenza, M.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Biasi, A. De; Decowski, M. P.; Deninno, M. M.; Waard, A. de; Domizio, S. Di; Ejzak, L.; Faccini, R.; Fang, D. Q.; Farach, H. A.; Ferri, E.; Ferroni, F.; Fiorini, E.; Foggetta, L.; Franceschi, M. A.; Freedman, S. J.; Frossati, G.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Guardincerri, E.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Huang, H. Z.; Ichimura, K.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kogler, L.; Kolomensky, Yu. G.; Kraft, S.; Lenz, D.; Li, Y. L.; Liu, X.; Longo, E.; Ma, Y. G.; Maiano, C.; Maier, G.; Maino, M.; Mancini, C.; Martinez, C.; Martinez, M.; Maruyama, R. H.; Moggi, N.; Morganti, S.; Napolitano, T.; Newman, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rimondi, F.; Rosenfeld, C.; Rusconi, C.; Salvioni, C.; Sangiorgio, S.; Schaeffer, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Stivanello, F.; Taffarello, L.; Terenziani, G.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Whitten Jr., C. A.; Wise, T.; Woodcraft, A.; Xu, N.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    2011-11-23

    In this paper, we study the sensitivity of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity are discussed and compared, and the formulas and parameters used in the sensitivity estimates are provided. Assuming a background rate of 10{sup -2} cts/(keV kg y), we find that, after 5 years of live time, CUORE will have a 1 {sigma} sensitivity to the neutrinoless double-beta decay half-life of {caret T{sup 0{nu}}{sub 1/2}}(1{sigma} ) = 1.6x 10{sup 26} y and thus a potential to probe the effective Majorana neutrino mass down to 41-95 meV; the sensitivity at 1.64{sigma} , which corresponds to 90% C.L., will be {caret T{sup 0{nu}}{sub 1/2}(1.64{sigma} }) = 9.5x10{sup 25} y. This range is compared with the claim of observation of neutrinoless double-beta decay in {sup 76}Ge and the preferred range in the neutrino mass parameter space from oscillation results.

  4. Measurement of the half-life of the two-neutrino double beta decay of 76Ge with the GERDA experiment

    NASA Astrophysics Data System (ADS)

    The GERDA Collaboration; Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Denisov, A.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A. D.; Freund, K.; Froborg, F.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gazzana, S.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kianovsky, S.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Pandola, L.; Pelczar, K.; Peraro, L.; Pullia, A.; Riboldi, S.; Ritter, F.; Sada, C.; Salathe, M.; Schmitt, C.; Schönert, S.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Walter, M.; Wegmann, A.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2013-03-01

    The primary goal of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of 76Ge. High-purity germanium detectors made from material enriched in 76Ge are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of 76Ge. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of 76Ge. The half-life extracted from GERDA data is T2ν1/2 = (1.84+0.14-0.10) × 1021 yr.

  5. First results of neutrinoless double beta decay search with the GERmanium Detector Array "GERDA"

    NASA Astrophysics Data System (ADS)

    Janicskó Csáthy, József

    2014-06-01

    The study of neutrinoless double beta decay is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of the lepton number violating neutrinoless double beta decay would establish the Majorana nature of the neutrino. Until now neutrinoless double beta decay was not observed. The GERmanium Detector Array, GERDA is a double beta decay experiment located at the INFN Gran Sasso National Laboratory, Italy. GERDA operates bare Ge diodes enriched in 76Ge in liquid argon supplemented by a water shield. The exposure accumulated adds up to 21.6 kg· yr with a background level of 1.8 · 10-2 cts/(keV·kg·yr). The results of the Phase I of the experiment are presented and the preparation of the Phase II is briefly discussed.

  6. The MAJORANA experiment: an ultra-low background search for neutrinoless double-beta decay

    SciTech Connect

    Phillips, D.; Aguayo Navarrete, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

    2012-12-01

    The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana Experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to validate whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.

  7. The Majorana Search for Neutrinoless Double-Beta Decay

    NASA Astrophysics Data System (ADS)

    Kazkaz, K.; Majorana Collaboration

    2005-06-01

    The Majorana experiment[ nucl-ex/0311013] is a proposed 76Ge-based search for neutrinoless double-beta (0 νββ) decay and dark matter (DM). It will use segmented, enriched germanium detectors in a close-pack configuration. With 500 kg of germanium, Majorana would be expected to reach a sensitivity to the 0 νββ decay half-life of 10 27 years, corresponding to a neutrino mass near the atmospheric mass scale. Current development efforts are presented, along with performance expectations and background reduction methods. Additionally, the status of the related detectors SEGA (Segmented Enriched Germanium Assembly) and MEGA[Kazkaz, K., Aalseth, C.E., Hossbach, T.W., Gehman, V.M., Kephart, J.D., Miley, H.S., IEEE Trans. Nuc. Sci. 51 (2004) 1029] (Multi-Element Gamma Assay) are presented. Current simulation efforts will be presented in a parallel poster by Reyco Henning.

  8. New techniques and results in sup 76 Ge double-beta decay

    SciTech Connect

    Miley, H.S.; Brodzinski, R.L.; Hensley, W.K.; Reeves, J.H. ); Avignone, F.T. . Dept. of Physics)

    1991-09-01

    Several methods of lowering the background in germanium double-beta decay experiments are discusses. A technique for increasing confidence in double-beta decay measurements by variation of detector enrichment is demonstrated in the case of two-neutrino decay mode of {sup 76}Ge. The impact of cosmic ray spallation in low-background isotopically enriched germanium detectors is examined.

  9. New techniques and results in {sup 76}Ge double-beta decay

    SciTech Connect

    Miley, H.S.; Brodzinski, R.L.; Hensley, W.K.; Reeves, J.H.; Avignone, F.T.

    1991-09-01

    Several methods of lowering the background in germanium double-beta decay experiments are discusses. A technique for increasing confidence in double-beta decay measurements by variation of detector enrichment is demonstrated in the case of two-neutrino decay mode of {sup 76}Ge. The impact of cosmic ray spallation in low-background isotopically enriched germanium detectors is examined.

  10. Neutrinoless double beta decay search with the NEMO 3 experiment

    SciTech Connect

    Nasteva, Irina

    2008-11-23

    The NEMO 3 experiment searches for neutrinoless double beta decay and makes precision measurements of two-neutrino double beta decay in seven isotopes. The latest two-neutrino half-life results are presented, together with the limits on neutrinoless half-lives and the corresponding effective Majorana neutrino masses. Also given are the limits obtained on neutrinoless double beta decay mediated by R{sub p}-violating SUSY, right-hand currents and different Majoron emission modes.

  11. The COBRA Neutrinoless Double Beta Experiment.

    NASA Astrophysics Data System (ADS)

    Li, Qiang

    2008-04-01

    The COBRA is a proposed experiment to detect neutrinoless double beta decays of the isotope 116Cd. The COBRA design is based on CZT room temperature solid state detectors. A prototype of the experiment made of 64 1cm^3 detectors is running in the Gran Sasso underground laboratory. In this talk, I will discuss the design of the COBRA prototype experiment and possible designs of a large-scale experiment made of 410 kg of CZT detectors. We are currently evaluating the option to use CZT detector units with 200 micron spatial resolution. Such detectors would make it possible to track the electrons from double beta decays and to distinguish them from certain types of background events.

  12. JUNO and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Ge, Shao-Feng; Rodejohann, Werner

    2015-11-01

    We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this value by a factor of 2. The remaining uncertainty is caused by nuclear matrix elements. This has important consequences for future double beta decay experiments that aim at ruling out the inverted mass ordering or the Majorana nature of neutrinos.

  13. Liquid Scintillator based experiments in Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; KamLAND-Zen Collaboration

    2012-08-01

    Recent experiments have confirmed neutrino oscillations. The mass structure of neutrinos is one of the next interesting subjects in neutrino physics. Neutrinoless double beta decay has the potential to investigate the mass structure of neutrinos. Many neutrinoless double beta decay experiments are being proposed and some were introduced at this conference. Here we present neutrinoless double beta decay experiments based on liquid scintillator techniques. SNO+ plans to use 150Nd as the neutrinoless double beta decay isotope dissolved in liquid scintillator, similarly KamLAND-Zen will use 136Xe loaded liquid scintillator. The physics goals, schedule and current status of both experiments were discussed.

  14. Search for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Ostrovskiy, Igor; O’Sullivan, Kevin

    2016-06-01

    We review current experimental efforts to search for neutrinoless double beta decay (0νββ). A description of the selected leading experiments is given and the strongest recent results are compared in terms of achieved background indexes (BI) and limits on effective Majorana mass. A combined limit is also shown. The second part of the review covers next generation experiments, highlighting the challenges and new technologies that may be necessary to achieve a justifiable discovery potential. A potential synergy with direct dark matter searches, which could be an especially prudent strategy in case the axial vector coupling constant is quenched in 0νββ decay, is emphasized.

  15. Semiconductor-based experiments for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Barnabé Heider, Marik; Gerda Collaboration

    2012-08-01

    Three experiments are employing semiconductor detectors in the search for neutrinoless double beta (0νββ) decay: COBRA, Majorana and GERDA. COBRA is studying the prospects of using CdZnTe detectors in terms of achievable energy resolution and background suppression. These detectors contain several ββ emitters and the most promising for 0νββ-decay search is 116Cd. Majorana and GERDA will use isotopically enriched high purity Ge detectors to search for 0νββ-decay of 76Ge. Their aim is to achieve a background ⩽10-3 counts/(kgṡyṡkeV) at the Q improvement compared to the present state-of-art. Majorana will operate Ge detectors in electroformed-Cu vacuum cryostats. A first cryostat housing a natural-Ge detector array is currently under preparation. In contrast, GERDA is operating bare Ge detectors submerged in liquid argon. The construction of the GERDA experiment is completed and a commissioning run started in June 2010. A string of natural-Ge detectors is operated to test the complete experimental setup and to determine the background before submerging the detectors enriched in 76Ge. An overview and a comparison of these three experiments will be presented together with the latest results and developments.

  16. COBRA - Neutrinoless Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Heidrich, Nadine

    2012-08-01

    The COBRA experiment is searching for neutrinoless double beta decay using CdZnTe semiconductor detectors. The main focus is on Cd-116, with a decay energy of 2814keV well above the highest naturally occurring gamma lines. Furthermore, Te-130, with a high natural abundance, and Cd-106, a double β+ emitter, are under investigation. Advantageous is the possibility to operate the detectors at room temperature. Besides coplanar grid detectors, pixelised detectors are considered. The latter ones would allow for particle discrimination, therefore providing efficient background reduction. The current status of the experiment is described, including the upgrade of the R&D set-up in spring 2011 at the LNGS underground laboratory, the different detector concepts and the latest half -life limits. Furthermore, studies on the use of liquid scintillator for background suppression and Monte-Carlo simulations are presented.

  17. Neutrinoless double beta decay search with SNO+

    NASA Astrophysics Data System (ADS)

    Lozza, V.

    2014-01-01

    The SNO+ experiment is the follow up of SNO. The detector is located 2 km underground in the Vale Canada Ltd.'s Creighton Mine near Sudbury, Ontario, Canada. The active volume of the detector consists of 780 tonnes of Linear Alkyl Benzene (LAB) in an acrylic vessel of 12 m diameter, surrounded by about 9500 PMTs. The main goal of the SNO+ experiment is the search for neutrinoless double beta decay of 130Te. With an initial loading of 0.3% of natural tellurium (nearly 800 kg of 130Te), it is expected to reach a sensitivity on the effective Majorana neutrino mass of about 100 meV after several years of data taking. Designed as a general purpose neutrino experiment, other exciting physical goals can be explored, like the measurement of reactor neutrino oscillations and geo-neutrinos in a geologically-interesting location, watch of supernova neutrinos and studies of solar neutrinos. A first commissioning phase with water filled detector will start at the end of 2013, while the double beta decay phase will start in 2015.

  18. The Gerda search for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    O'Shaughnessy, Christopher; Gerda Collaboration

    2013-10-01

    The Germanium Detector Array (Gerda) is a search for the neutrinoless double beta decay of 76Ge. High Purity Germanium (HPGe) detectors enriched in the isotope-76 are operated bare in liquid argon (LAr). LAr is used for both cooling of the HPGe diodes to their operating temperatures and for shielding from external radiation sources. From the measurements of the first phase that began data taking on 1 Nov. 2011 it is expected to have a sensitivity on the level of T1/2>2E25 yr at a 90% CL after 15 kġyr. The goal of this phase will be to probe the claim of an observation by part of the Heidelberg-Moscow collaboration. Efforts will then focus on increasing the sensitivity of the experiment by deploying additional enriched detectors that are in an advanced stage of production and by reducing the background index further by making use of pulse shape discrimination techniques as well as an active LAr veto. While the 0νββ region of interest continues to remain blinded, here the status of Phase-I data taking is presented along with the work towards improving the experimental sensitivity.

  19. MAJORANA Neutrinoless Double-Beta Decay DUSEL R&D

    SciTech Connect

    Wilkerson, John F.

    2009-09-04

    The Majorana research and development is addressing key issues and risks related to the collaboration's goal of undertaking a search for neutrinoless double-beta decay (0{nu}{beta}{beta}) in {sup 76}Ge using an array of hyper-pure Ge-diodes (HPGe). The observation of this decay would provide critical insight into our understanding of neutrinos, yielding definitive evidence that neutrinos are Majorana particles and providing information on the absolute mass of neutrinos. Achieving sensitivities to 0{nu}{beta}{beta} decay half-lives on the order of 10{sup 26} years requires ultra-low backgrounds in the 2039 keV region where a 0{nu}{beta}{beta} decay peak would be observed. The goal of our R&D program has been to demonstrate the feasibility of all components of Majorana and to provide an integrated evaluation framework, allowing for optimization of these components in terms of background, background suppression, and signal detection efficiency and acceptance. This report covers work carried out by Majorana collaboration members at the University of Washington as part of the overall Majorana collaboration activities. Specifically the Majorana group at the University of Washington was involved in moving forward on demonstrating technology for clean large-scale cryostats and mounting the HPGe crystals in low-mass holders. The UW activities included assistance in the procurement and assembly of an electroforming system for large size cryostats, and design and fabrication of prototype crystal mounting hardware.

  20. What can we learn from neutrinoless double beta decay experiments?

    SciTech Connect

    Bahcall, John N.; Murayama, Hitoshi; Pena-Garay, Carlos

    2004-04-08

    We assess how well next generation neutrinoless double beta decay and normal neutrino beta decay experiments can answer four fundamental questions. 1) If neutrinoless double beta decay searches do not detect a signal, and if the spectrum is known to be inverted hierarchy, can we conclude that neutrinos are Dirac particles? 2) If neutrinoless double beta decay searches are negative and a next generation ordinary beta decay experiment detects the neutrino mass scale, can we conclude that neutrinos are Dirac particles? 3) If neutrinoless double beta decay is observed with a large neutrino mass element, what is the total mass in neutrinos? 4) If neutrinoless double beta decay is observed but next generation beta decay searches for a neutrino mass only set a mass upper limit, can we establish whether the mass hierarchy is normal or inverted? We base our answers on the expected performance of next generation neutrinoless double beta decay experiments and on simulations of the accuracy of calculations of nuclear matrix elements.

  1. Nuclear Structure Relevant to Double-beta Decay: Studies of 76Ge and 76Se using Inelastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Crider, Benjamin P.

    While neutrino oscillations indicate that neutrino flavors mix and that neutrinos have mass, they do not supply information on the absolute mass scale of the three flavors of neutrinos. Currently, the only viable way to determine this mass scale is through the observation of the theoretically predicted process of neutrinoless double-beta decay (0nubetabeta). This yet-to-be-observed decay process is speculated to occur in a handful of nuclei and has predicted half-lives greater than 1025 years. Observation of 0nubetabeta is the goal of several large-scale, multinational efforts and consists of detecting a sharp peak in the summed energies at the Q-value of the reaction. An exceptional candidate for the observation of 0nubetabeta is 76Ge, which offers an excellent combination of capabilities and sensitivities, and two such collaborations, MAJORANA and GERDA, propose tonne-scale experiments that have already begun initial phases using a fraction of the material. The absolute scale of the neutrino masses hinges on a matrix element, which depends on the ground-state wave functions for both the parent (76Ge) and daughter (76Se) nuclei in the 0nubetabeta decay and can only be calculated from nuclear structure models. Efforts to provide information on the applicability of these models have been undertaken at the University of Kentucky Accelerator Laboratory using gamma-ray spectroscopy following inelastic scattering reactions with monoenergetic, accelerator-produced fast neutrons. Information on new energy levels and transitions, spin and parity assignments, lifetimes, multipole mixing ratios, and transition probabilities have been determined for 76Se, the daughter of 76Ge 0nubetabeta, up to 3.0 MeV. Additionally, inaccuracies in the accepted level schemes have been addressed. Observation of 0nubetabeta requires precise knowledge of potential contributors to background within the region of interest, i.e., approximately 2039 keV for 76Ge. In addition to backgrounds

  2. Theory of neutrinoless double-beta decay.

    PubMed

    Vergados, J D; Ejiri, H; Simkovic, F

    2012-10-01

    Neutrinoless double-beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that the lepton number is not conserved and that the neutrinos are Majorana particles. More importantly it is our best hope for determining the absolute neutrino-mass scale at the level of a few tens of meV. To achieve the last goal certain hurdles must be overcome involving particle, nuclear and experimental physics. Nuclear physics is important for extracting useful information from the data. One must accurately evaluate the relevant nuclear matrix elements--a formidable task. To this end, we review the sophisticated nuclear structure approaches which have recently been developed, and which give confidence that the required nuclear matrix elements can be reliably calculated employing different methods: (a) the various versions of the quasiparticle random phase approximations, (b) the interacting boson model, (c) the energy density functional method and (d) the large basis interacting shell model. It is encouraging that, for the light neutrino-mass term at least, these vastly different approaches now give comparable results. From an experimental point of view it is challenging, since the life times are long and one has to fight against formidable backgrounds. One needs large isotopically enriched sources and detectors with high-energy resolution, low thresholds and very low background. If a signal is found, it will be a tremendous accomplishment. The real task then, of course, will be the extraction of the neutrino mass from the observations. This is not trivial, since current particle models predict the presence of many mechanisms other than the neutrino mass, which may contribute to or even dominate this process. In particular, we will consider the following processes: The neutrino induced, but neutrino-mass independent contribution. Heavy left and/or right-handed neutrino-mass contributions. Intermediate scalars (doubly charged, etc

  3. Theory of neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.; Ejiri, H.; Šimkovic, F.

    2012-10-01

    Neutrinoless double-beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that the lepton number is not conserved and that the neutrinos are Majorana particles. More importantly it is our best hope for determining the absolute neutrino-mass scale at the level of a few tens of meV. To achieve the last goal certain hurdles must be overcome involving particle, nuclear and experimental physics. Nuclear physics is important for extracting useful information from the data. One must accurately evaluate the relevant nuclear matrix elements—a formidable task. To this end, we review the sophisticated nuclear structure approaches which have recently been developed, and which give confidence that the required nuclear matrix elements can be reliably calculated employing different methods: (a) the various versions of the quasiparticle random phase approximations, (b) the interacting boson model, (c) the energy density functional method and (d) the large basis interacting shell model. It is encouraging that, for the light neutrino-mass term at least, these vastly different approaches now give comparable results. From an experimental point of view it is challenging, since the life times are long and one has to fight against formidable backgrounds. One needs large isotopically enriched sources and detectors with high-energy resolution, low thresholds and very low background. If a signal is found, it will be a tremendous accomplishment. The real task then, of course, will be the extraction of the neutrino mass from the observations. This is not trivial, since current particle models predict the presence of many mechanisms other than the neutrino mass, which may contribute to or even dominate this process. In particular, we will consider the following processes: The neutrino induced, but neutrino-mass independent contribution. Heavy left and/or right-handed neutrino-mass contributions. Intermediate scalars (doubly charged, etc

  4. Background Suppression Using Pulse Shape Analysis with a BEGe Detector for Neutrinoless Double Beta Decay Search with GERDA

    SciTech Connect

    Budjas, Dusan; Schoenert, Stefan; Chkvorets, Oleg

    2009-12-17

    A pulse shape analysis for distinguishing between double beta decay-like interactions and multiple-scattered photons was performed for the first time using a BEGe-type detector. This discrimination method is included in the research and development for the second phase of the GERDA experiment, since active background suppression techniques are necessary to reach sensitivity for the {sup 76}Ge neutrinoless double beta decay half life of >10{sup 26} years. A suppression of backgrounds in the energy region of interest around the {sup 76}Ge Q{sub {beta}}{sub {beta}} = 2039 keV is demonstrated, with (0.93{+-}0.08)% survival probability for events from {sup 60}Co, (21{+-}3)% for {sup 226}Ra, and (40{+-}2)% for {sup 228}Th. This performance is achieved with (89{+-}1)% acceptance of {sup 228}Th double escape events, which are analogous to double beta decay.

  5. Neutrinoless double-beta decay and neutrino physics

    NASA Astrophysics Data System (ADS)

    Rodejohann, Werner

    2012-12-01

    The connection of neutrino physics with the neutrinoless double-beta decay is reviewed. After presenting the current status of the Pontecorvo-Maki-Nakagawa-Sakata matrix and the theoretical background of neutrino mass and lepton mixing, we will summarize the various implications of neutrino physics for the double-beta decay. The influence of light sterile neutrinos and other exotic modifications of the three neutrino picture is also discussed.

  6. Phase II Upgrade of the GERDA Experiment for the Search of Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Majorovits, B.

    Observation of neutrinoless double beta decay could answer the question regarding the Majorana or Dirac nature of neutrinos. The GERDA experiment utilizes HPGe detectors enriched with the isotope 76Ge to search for this process. Recently the GERDA collaboration has unblinded data of Phase I of the experiment. In order to further improve the sensitivity of the experiment, additionally to the coaxial detectors used, 30 BEGe detectors made from germanium enriched in 76Ge will be deployed in GERDA Phase II. BEGe detectors have superior PSD capability, thus the background can be further reduced. The liquid argon surrounding the detector array will be instrumented in order to reject background by detecting scintillation light induced in the liquid argon by radiation. After a short introduction the hardware preparations for GERDA Phase II as well as the processing and characterization of the 30 BEGe detectors are discussed.

  7. Alpha Backgrounds for HPGe Detectors in Neutrinoless Double-Beta Decay Experiments

    SciTech Connect

    Johnson, R. A.; Burritt, T. H.; Elliott, S. R.; Gehman, V. M.; Guiseppe, V.E.; Wilkerson, J. F.

    2012-01-01

    The Majorana Experiment will use arrays of enriched HPGe detectors to search for the neutrinoless double-beta decay of 76Ge. Such a decay, if found, would show lepton-number violation and confirm the Majorana nature of the neutrino. Searches for such rare events are hindered by obscuring backgrounds which must be understood and mitigated as much as possible. A potentially important background contribution to this and other double-beta decay experiments could come from decays of alpha-emitting isotopes in the 232Th and 238U decay chains on or near the surfaces of the detectors. An alpha particle emitted external to an HPGe crystal can lose energy before entering the active region of the detector, either in some external-bulk material or within the dead region of the crystal. The measured energy of the event will only correspond to a partial amount of the total kinetic energy of the alpha and might obscure the signal from neutrinoless double-beta decay. A test stand was built and measurements were performed to quantitatively assess this background. We present results from these measurements and compare them to simulations using Geant4. These results are then used to measure the alpha backgrounds in an underground detector in situ. We also make estimates of surface contamination tolerances for double-beta decay experiments using solid-state detectors.

  8. The Majorana Demonstrator: A search for neutrinoless double-beta decay of germanium-76

    SciTech Connect

    Elliott, S. R.; Boswell, M.; Goett, J.; Rielage, K.; Ronquest, M. C.; Xu, W.; Abgrall, N.; Chan, Y-D.; Hegai, A.; Martin, R. D.; Mertens, S.; Poon, A. W. P.; Aguayo, E.; Fast, J. E.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Overman, N. R.; Soin, A.; and others

    2013-12-30

    The MAJORANA collaboration is searching for neutrinoless double beta decay using {sup 76}Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, 15 - 50 meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of ∼1 count/t-y or lower in the region of the signal. The MAJORANA collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the DEMONSTRATOR, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which ∼30 kg will be enriched to 87% in {sup 76}Ge. The DEMONSTRATOR is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the DEMONSTRATOR is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.

  9. Results on neutrinoless double-β decay of 76Ge from phase I of the GERDA experiment.

    PubMed

    Agostini, M; Allardt, M; Andreotti, E; Bakalyarov, A M; Balata, M; Barabanov, I; Barnabé Heider, M; Barros, N; Baudis, L; Bauer, C; Becerici-Schmidt, N; Bellotti, E; Belogurov, S; Belyaev, S T; Benato, G; Bettini, A; Bezrukov, L; Bode, T; Brudanin, V; Brugnera, R; Budjáš, D; Caldwell, A; Cattadori, C; Chernogorov, A; Cossavella, F; Demidova, E V; Domula, A; Egorov, V; Falkenstein, R; Ferella, A; Freund, K; Frodyma, N; Gangapshev, A; Garfagnini, A; Gotti, C; Grabmayr, P; Gurentsov, V; Gusev, K; Guthikonda, K K; Hampel, W; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Ioannucci, L; Janicskó Csáthy, J; Jochum, J; Junker, M; Kihm, T; Kirpichnikov, I V; Kirsch, A; Klimenko, A; Knöpfle, K T; Kochetov, O; Kornoukhov, V N; Kuzminov, V V; Laubenstein, M; Lazzaro, A; Lebedev, V I; Lehnert, B; Liao, H Y; Lindner, M; Lippi, I; Liu, X; Lubashevskiy, A; Lubsandorzhiev, B; Lutter, G; Macolino, C; Machado, A A; Majorovits, B; Maneschg, W; Misiaszek, M; Nemchenok, I; Nisi, S; O'Shaughnessy, C; Pandola, L; Pelczar, K; Pessina, G; Pullia, A; Riboldi, S; Rumyantseva, N; Sada, C; Salathe, M; Schmitt, C; Schreiner, J; Schulz, O; Schwingenheuer, B; Schönert, S; Shevchik, E; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Strecker, H; Tarka, M; Ur, C A; Vasenko, A A; Volynets, O; von Sturm, K; Wagner, V; Walter, M; Wegmann, A; Wester, T; Wojcik, M; Yanovich, E; Zavarise, P; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2013-09-20

    Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the standard model of particle physics. This Letter reports the results from phase I of the Germanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory (Italy) searching for neutrinoless double beta decay of the isotope (76)Ge. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1 × 10(-2) counts/(keV kg yr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of (76)Ge, T(1/2)(0ν) >2.1 × 10(25) yr (90% C.L.). The combination with the results from the previous experiments with (76)Ge yields T(1/2)(0ν)>3.0 × 10(25) yr (90% C.L.). PMID:24093254

  10. Neutrinoless Double Beta Decay and {nu}-Mass Determination

    SciTech Connect

    Pedretti, M.

    2005-10-12

    The search for Neutrinoless Double Beta Decay could improve our knowledge on neutrino properties. After a brief discussion on the implications of the observation of this rare process, I will introduce the experimental approaches and review the prospects of the search for this nuclear transition.

  11. Microscopic calculations of signals of double beta decay in a 76Ge detector and first application to the Heidelberg Moscow experiment

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, H. V.; Krivosheina, I. V.; Mironov, V.; Titkova, I. V.

    2006-05-01

    The identification of signals of neutrinoless double beta decay is a question of extreme interest. Starting from the Monte Carlo calculated time history and spatial energy distribution of neutrinoless double beta events, for the first time the expected pulse shapes to be observed in a big 76Ge detector have been calculated 'microscopically', by using the Poisson Superfish code for determination of the field distribution in the detector. It is shown, that for the majority of 0 νββ events it is not possible to differentiate between the contributions of different particle physics parameters entering into the 0 νββ decay process-in the mass mechanism the effective neutrino mass and the right-handed weak current parameters < λ >, < η >. It is shown, that on the other hand it is possible in a 76Ge double beta decay experiment to reject a background of larger sizes (high multiplicity) gamma events by selecting low size (low multiplicity) events. First application of the theoretical ββ pulses to events from the line observed at Qββ [H.V. Klapdor-Kleingrothaus, I.V. Krivosheina, A. Dietz, et al., Phys. Lett. B 586 (2004) 198; H.V. Klapdor-Kleingrothaus, A. Dietz, I.V. Krivosheina, et al., Nucl. Instrum. Methods A 522 (2004) 371] shows very good agreement. It is shown further, and confirmed by measurements with a collimated source, that a rather good radial position determination of ββ events in the detector is possible. By the same type of calculation it is shown that use of the pulse shapes of the 1592 keV double escape line of the 2614 keV γ-transition from 228Th for calibrating a neuronal net for search of events of neutrinoless double beta decay can be helpful.

  12. A search for neutrinoless double beta decay of tellurium-130

    NASA Astrophysics Data System (ADS)

    Bryant, Adam Douglas

    This dissertation describes an experimental search for neutrinoless double beta (0nubetabeta) decay of 130Te. An observation of 0nubetabeta decay would establish that neutrinos are Majorana fermions and would constrain the neutrino mass scale. The data analyzed were collected by two bolometric experiments: CUORICINO and an R&D experiment for CUORE known as the Three Towers Test. Both experiments utilized arrays of TeO 2 crystals operated as bolometers at ˜10 mK in a dilution refrigerator. The bolometers measured the energy deposited by particle interactions in the crystals by recording the induced change in crystal temperature. Between the two experiments, there were 81 TeO2 bolometers used in the analysis, each of which was an independent detector of nuclear decays as well as a source of 130Te. The experiments were conducted underground at a depth of about 3300 meters water equivalent in Hall A of the Laboratori Nazionali del Gran Sasso in Assergi, Italy, in order to shield the detectors from cosmic rays. The data analyzed represent an exposure of 19.9 kg · y of 130Te (18.6 kg · y from CUORICINO and 1.3 kg · y from the Three Towers Test). In addition to the combined analysis of the two experiments, an analysis of CUORICINO data alone is presented in order to compare with an independent analysis being carried out by collaborators at the University of Milano-Bicocca. No signal due to 0nubetabeta decay is observed, and therefore a limit on the partial half-life for the decay is set. From a simultaneous fit to the 81 independent detectors, the rate of 0nubetabeta decay of 130Te is measured to be Gamma0nubetabeta( 130Te) = (-0.6+/-1.4 (stat.) +/- 0.4 (syst.)) x 10-25 y-1, which corresponds to a lower limit on the partial half-life for 0nubetabeta decay of 130Te of T0nbb1/2 (130Te) > 3.0x1024 y (90% C.L.). Converting the half-life limit to an upper limit on the effective Majorana neutrino mass, mbetabeta, using a set of recent nuclear matrix element calculations

  13. Complementarity of Neutrinoless Double Beta Decay and Cosmology

    SciTech Connect

    Dodelson, Scott; Lykken, Joseph

    2014-03-20

    Neutrinoless double beta decay experiments constrain one combination of neutrino parameters, while cosmic surveys constrain another. This complementarity opens up an exciting range of possibilities. If neutrinos are Majorana particles, and the neutrino masses follow an inverted hierarchy, then the upcoming sets of both experiments will detect signals. The combined constraints will pin down not only the neutrino masses but also constrain one of the Majorana phases. If the hierarchy is normal, then a beta decay detection with the upcoming generation of experiments is unlikely, but cosmic surveys could constrain the sum of the masses to be relatively heavy, thereby producing a lower bound for the neutrinoless double beta decay rate, and therefore an argument for a next generation beta decay experiment. In this case as well, a combination of the phases will be constrained.

  14. Extra dimensions and neutrinoless double beta decay experiments

    SciTech Connect

    Gozdz, Marek; Kaminski, Wieslaw A.; Faessler, Amand

    2005-05-01

    The neutrinoless double beta decay is one of the few phenomena, belonging to the nonstandard physics, which is extensively being sought for in experiments. In the present paper the link between the half-life of the neutrinoless double beta decay and theories with large extra dimensions is explored. The use of the sensitivities of currently planned 0{nu}2{beta} experiments: DAMA, CANDLES, COBRA, DCBA, CAMEO, GENIUS, GEM, MAJORANA, MOON, CUORE, EXO, and XMASS, gives the possibility for a nondirect 'experimental' verification of various extra dimensional scenarios. We discuss also the results of the Heidelberg-Moscow Collaboration. The calculations are based on the Majorana neutrino mass generation mechanism in the Arkani-Hamed-Dimopoulos-Dvali model.

  15. Disentangling the various Mechanisms of neutrinoless double beta decay to extract the neutrino mass

    SciTech Connect

    Vergados, J. D.

    2011-12-16

    It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay. By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, given the observation of the 0{nu}{beta}{beta}-decay in three different nuclei, e.g. {sup 76}Ge, {sup 100}Mo and {sup 130}Te, and assuming just three active lepton number violating parameters, e.g. light and heavy neutrino mass mechanisms in left handed currents as well as R-parity breaking SUSY mechanism, one may determine all lepton violating parameters, provided that they are relatively real.

  16. A Segmented, Enriched N-type Germanium Detector for Neutrinoless Double Beta-Decay Experiments

    SciTech Connect

    Leviner, L.; Aalseth, Craig E.; Ahmed, M. W.; Avignone, F. T.; Back, Henning O.; Barabash, Alexander S.; Boswell, M.; De Braeckeleer, L.; Brudanin, V.; Chan, Yuen-Dat; Egorov, Viatcheslav; Elliott, Steven R.; Gehman, Victor M.; Hossbach, Todd W.; Kephart, Jeremy; Kidd, M. F.; Konovalov, S.; Lesko, Kevin; Li, Jingyi; Mei, Dongming; Mikhailov, S.; Miley, Harry S.; Radford, D. C.; Reeves, James H.; Sandukovsky, Viatcheslav; Umatov, Valdimir; Underwood, T. A.; Tornow, W.; Wu, Y. K.; Young, A.

    2014-01-21

    We present data characterizing the performance of the _rst segmented, N- type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6x2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the Majorana collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the Majorana resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.

  17. Status of the MAJORANA DEMONSTRATOR: A search for neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Efremenko, Yu.; Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Laferriere, B. D.; Leon, J.; Macmullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2015-04-01

    If neutrinos are Majorana particles, i.e. fermions that are their own antiparticles, then neutrinoless double-beta (0νββ) decay is possible. In such a process, two neutrons can simultaneously decay into two protons and two electrons without emitting neutrinos. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The MAJORANA DEMONSTRATOR experiment is under construction at the Sanford Underground Research Facility in Lead, SD and will search for the neutrinoless double-beta (0νββ) decay of the 76Ge isotope. The goal of the experiment is to demonstrate that it is possible to achieve a sufficiently low background rate in the 4 keV region of interest (ROI) around the 2039 keV Q-value to justify building a tonne-scale experiment. In this paper, we discuss the physics and design of the MAJORANA DEMONSTRATOR, its approach to achieving ultra-low background and the status of the experiment.

  18. Status of the MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-Beta Decay

    NASA Astrophysics Data System (ADS)

    Efremenko, Yu.; Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Laferriere, B. D.; Leon, J.; Macmullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    If neutrinos are Majorana particles, i.e. fermions that are their own antiparticles, then neutrinoless double-beta (0νββ) decay is possible. In such a process, two neutrons can simultaneously decay into two protons and two electrons without emitting neutrinos. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The MAJORANA DEMONSTRATOR experiment is under construction at the Sanford Underground Research Facility in Lead, SD and will search for the neutrinoless double-beta (0νββ) decay of the 76Ge isotope. The goal of the experiment is to demonstrate that it is possible to achieve a sufficiently low background rate in the 4 keV region of interest (ROI) around the 2039 keV Q-value to justify building a tonne-scale experiment. In this paper, we discuss the physics and design of the MAJORANA DEMONSTRATOR, its approach to achieving ultra-low background and the status of the experiment.

  19. Search for the neutrinoless ββ decay in 76Ge with the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Cattadori, C.; Knapp, M.; Kröninger, K.; Liu, X.; Pandola, L.; Pullia, A.; Tomei, C.; Ur, C.; Zocca, F.; Gerda Collaboration

    2011-12-01

    The GERmanium Detector Array, GERDA, [Gerda Collaboration, Abt I et al., Proposal, a http://www.mpi-hd.mpg.de/ge76/home.html] is designed to search for neutrinoless double beta (0νββ)-decay of 76Ge. The importance of such a search is emphasized by the evidence of a non-zero neutrino mass from flavour oscillation experiments and by the recent claim [Klapdor-Kleingrothaus H V et al., Phys. Lett. B 586, 198 (2004)] based on data of the Heidelberg-Moscow experiment. GERDA will be installed in the Hall A of the Gran Sasso underground Laboratory (LNGS), Italy. The construction of GERDA will start in 2006.

  20. Neutrinoless double beta decay in Gerda

    NASA Astrophysics Data System (ADS)

    Grabmayr, Peter; Gerda Collaboration

    2015-10-01

    The Germanium Detector Array (Gerda) experiment searches for the neutrinoless double beta decay in 76Ge. This lepton number violating process is predicted by extensions of the standard model. Gerda follows a staged approach by increasing mass and lowering the background level from phase to phase. Gerda is setup at the Gran Sasso underground laboratory of INFN, Italy. An array of high-purity germanium detectors is lowered directly in liquid argon for shielding and cooling. Further background reduction is achieved by an instrumented water buffer. In Phase I an exposure of 21.6 kg yr was collected at a background level of 10-2 cts/(keV kg yr). The lower limit on the half-life of 76Ge > 2 . 1 .1025 yr (90% C.L.) has been published. Further analyses search for decay into excited states or the accompanied Majoron decay. Presently, Phase II is in preparation which intends to reach a background level of 10-3 cts/(keV kg yr) and to increase the exposure to 100 kg yr. About 20 kg of novel thick-window BEGe (Broad Energy Germanium) detectors will be added and the liquid argon will be instrumented. The status of Phase II preparation and results from the commissioning runs will be presented as well as some further results from Phase I.

  1. Effect of cancellation in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Mitra, Manimala; Pascoli, Silvia; Wong, Steven

    2014-11-01

    In light of recent experimental results, we carefully analyze the effects of interference in neutrinoless double beta decay, when more than one mechanism is operative. If a complete cancellation is at work, the half-life of the corresponding isotope is infinite, and any constraint on it will automatically be satisfied. We analyze this possibility in detail assuming a cancellation in Xe 136 , and find its implications on the half-life of other isotopes, such as Ge 76 . For definiteness, we consider the role of light and heavy sterile neutrinos. In this case, the effective Majorana mass parameter can be redefined to take into account all contributions, and its value gets suppressed. Hence, larger values of neutrino masses are required for the same half-life. The canonical light neutrino contribution cannot saturate the present limits of half-lives or the positive claim of observation of neutrinoless double beta decay, once the stringent bounds from cosmology are taken into account. For the case of cancellation, where all the sterile neutrinos are heavy, the tension between the results from neutrinoless double beta decay and cosmology becomes more severe. We show that the inclusion of light sterile neutrinos in this setup can resolve this issue. Using the recent results from GERDA, we derive upper limits on the active-sterile mixing angles and compare them with the case of no cancellation. The required values of the mixing angles become larger, if a cancellation is at work. A direct test of destructive interference in Xe 136 is provided by the observation of this process in other isotopes, and we study in detail the correlation between their half-lives. Finally, we discuss the model realizations which can accommodate light and heavy sterile neutrinos and the cancellation. We show that sterile neutrinos of few hundred MeV or GeV mass range, coming

  2. Hot Dark Matter and Neutrinoless Double Beta Decay:. World Status of the Field

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, Hans V.

    2008-04-01

    A final independent analysis of the data of the 76Ge experiment in Gran Sasso (HEIDELBERG-MOSCOW experiment) which is since 15 years the worldwide by far most sensitive double beta experiment, is presented for the main set of data taken in the period Nov. 1995 - May 2003.4,5 In this period the time structure of all events have been registered. Two different methods of pulse shape analysis4,5,7-9,15,17-19 lead to selection of potential 0νββ events at Qββ with almost no γ-background in a wide range around Qββ. The background achieved in the energy region of the Qββ value for double beta decay is 5.10-3 events kg-1yr-1keV-1. A line at Qββ is observed at a confidence level of more than 6σ. The identification of this line as signal of neutrinoless double beta decay is the most reasonable explanation. This means total lepton number violation and a Majorana nature of the neutrino as fundamental consequences for particle physics. The half-life for this process is determined to be <=ft(2.23+0.44-0.31(stat); ) × 1025 y. Assuming vanishing right-handed weak currents or other more exotic contributions to the 0νββ decay amplitude, a value of < m > = <=ft (0.32+0.03-0.03 ; ) eV is derived. Normalizing the nuclear matrix element for 2νββ decay to the experimental value, the lower limit for could be lower, down to 0.22 eV. With this value neutrinos contribute at least 4.7% to the dark matter in the Universe.

  3. First neutrinoless double beta decay results from CUORE-0

    NASA Astrophysics Data System (ADS)

    Gironi, L.; Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.

    2015-10-01

    The CUORE-0 experiment, a 52 bolometer array searching for neutrinoless double beta decay from 130Te, has started taking data in spring 2013 underground at the Laboratori Nazionali del Gran Sasso (LNGS). The excellent results obtained in terms of energy resolution and background level allowed this experiment to reach the sensitivity of Cuoricino in approximately half the runtime. Combining CUORE-0 data (9.8 kg.yr exposure of 130Te) with the 19.75 kg.yr exposure of the Cuoricino experiment, we obtain the most stringent limit to date on the half-life of this isotope (T1/2 > 4.0 × 1024 yr). In this article, we review the results from CUORE-0 and discuss the status and the physics potential of CUORE, a 19 times larger bolometer array that plans to begin operations by end of this year.

  4. Recent results from cosmology and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Dell’Oro, Stefano; Marcocci, Simone

    2016-05-01

    We quantify the impact of cosmological surveys on the search for neutrinoless double beta decay (0vββ) within the hypothesis that the 0vββ rate is dominated by the Majorana mass of ordinary neutrinos. In particular, we exploit the potential relevance of the work of Palanque-Delabrouille et al. [JCAP 1502, 045 (2015)], whose result seems to favor the normal hierarchy spectrum for the light neutrino masses. The impact of our analysis for the future generation of 0vββ experiments is quite dramatic and motivates further cosmological studies, both theoretically and experimentally. In fact, the allowed values for the Majorana Effective Mass turn out to be < 75meV at 3σ C.L, lowering down to less than 20 meV at 1σ C.L.

  5. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    DOE PAGESBeta

    Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y. -D.; et al

    2014-01-01

    Tmore » he M ajorana D emonstrator will search for the neutrinoless double-beta ( β β 0 ν ) decay of the isotope Ge with a mixed array of enriched and natural germanium detectors.he observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino.he D emonstrator is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota.he array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the D emonstrator and the details of its design. « less

  6. Ground state occupation probabilities of neutrinoless double beta decay candidates

    NASA Astrophysics Data System (ADS)

    Kotila, Jenni; Barea, Jose

    2015-10-01

    A better understanding of nuclear structure can offer important constraints on the calculation of 0 νββ nuclear matrix elements. A simple way to consider differences between initial and final states of neutrinoless double beta decay candidates is to look at the ground state occupation probabilities of initial and final nuclei. As is well known, microscopic interacting boson model (IBM-2) has found to be very useful in the description of detailed aspects of nuclear structure. In this talk I will present results for ground state occupation probabilities obtained using IBM-2 for several interesting candidates of 0 νββ -decay. Comparison with recent experimental results is also made. This work was supported Academy of Finland (Project 266437) and Chilean Ministry of Education (Fondecyt Grant No. 1150564),

  7. Neutrinoless double-beta decay in covariant density functional theory

    SciTech Connect

    Ring, P.; Yao, J. M.; Song, L. S.; Hagino, K.; Meng, J.

    2015-10-15

    We use covariant density functional theory beyond mean field in order to describe neutrinoless double-beta decay in a fully relativistic way. The dynamic effects of particle-number and angular-momentum conservations as well as shape fluctuations of quadrupole character are taken into account within the generator coordinate method for both initial and final nuclei. The calculations are based on the full relativistic transition operator. The nuclear matrix elements (NME’s) for a large number of possible transitions are investigated. The results are compared with various non-relativistic calculations, in particular also with the density functional theory based on the Gogny force. We find that the non-relativistic approximation is justified and that the total NME’s can be well approximated by the pure axial-vector coupling term. This corresponds to a considerable reduction of the computational effort.

  8. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    SciTech Connect

    Abgrall, N.; Aguayo, Estanislao; Avignone, III, F. T.; Barabash, A.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, Mark D.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Steele, David; Strain, J.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Williams, T.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-01-01

    The Majorana Demonstrator will search for the neutrinoless double-beta (ββ (0ν)) decay of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. TheDemonstrator is being assembled at the 4850-foot level of the SanfordUnderground Research Facility in Lead, SouthDakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the Demonstrator and the details of its design.

  9. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    SciTech Connect

    Abgrall, N.; Aguayo, Estanislao; Avignone, Frank T.; Barabash, Alexander S.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, C.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Steele, David; Strain, J.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Williams, T.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-06-01

    The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta (ββ(0ν)) decay of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the DEMONSTRATOR and the details of its design.

  10. Neutrinoless double-beta decay in covariant density functional theory

    NASA Astrophysics Data System (ADS)

    Ring, P.; Yao, J. M.; Song, L. S.; Hagino, K.; Meng, J.

    2015-10-01

    We use covariant density functional theory beyond mean field in order to describe neutrinoless double-beta decay in a fully relativistic way. The dynamic effects of particle-number and angular-momentum conservations as well as shape fluctuations of quadrupole character are taken into account within the generator coordinate method for both initial and final nuclei. The calculations are based on the full relativistic transition operator. The nuclear matrix elements (NME's) for a large number of possible transitions are investigated. The results are compared with various non-relativistic calculations, in particular also with the density functional theory based on the Gogny force. We find that the non-relativistic approximation is justified and that the total NME's can be well approximated by the pure axial-vector coupling term. This corresponds to a considerable reduction of the computational effort.

  11. The Nuclear and Particle Physics of Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Haxton, Wick

    2014-03-01

    Fortuitous properties of nuclei allow us to isolate and study the rare second-order weak process of double beta decay. In particular, the decay channel in which a final state of two electrons and no neutrinos is produced - neutrinoless double beta decay - provides our best test of lepton number conservation and the Majorana mass of the electron neutrino. I will describe the connections between this process and the charge conjugation properties of the neutrino, including the possibility that the presence of both Dirac and Majorana masses accounts for the anomalous scale of neutrino masses. The extraordinary progress made over the past two decades has prepared the way for next-generation experiments that will probe Majorana masses at levels where nonzero rates may be found, given what we now know about neutrino mass splittings. I will describe some of the heroic efforts underway to develop detectors of unprecedented size, radiopurity, depth, and thus sensitivity. Work supported by the Office of Science, US DOE.

  12. Results on Neutrinoless Double-Beta Decay from Gerda Phase I

    NASA Astrophysics Data System (ADS)

    Macolino, Carla

    2014-12-01

    The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double-beta (0νββ) decay of 76Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the detection principle and detector setup of GERDA are described. Also, the main physics results by GERDA Phase I, are discussed. They include the measurement of the half-life of 2νββ decay, the background decomposition of the energy spectrum and the techniques for the discrimination of the background, based on the pulse shape of the signal. In the last part of this review, the estimation of a limit on the half-life of 0νββ (T0ν 1/2>2.1ḑot 1025 yr at 90% C.L.) and the comparison with previous results are discussed. GERDA data from Phase I strongly disfavor the recent claim of 0νββ discovery, based on data from the Heidelberg-Moscow experiment.

  13. The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Detwiler, J. A.; Finnerty, P.; Kröninger, K.; Lenz, D.; Liu, J.; Marino, M. G.; Martin, R.; Nguyen, K. D.; Pandola, L.; Schubert, A. G.; Volynets, O.; Zavarise, P.

    2012-07-01

    The Gerda and Majorana experiments will search for neutrinoless double-beta decay of 76Ge using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, allowing for easy extension and customization of the components. The tools provided by the MGDO libraries are used by both Gerda and Majorana.

  14. The Majorana Demonstrator Neutrinoless Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Massarczyk, Ralph; Majorana Collaboration

    2016-03-01

    Neutrinoless double beta decay searches play a major role in determining neutrino properties. The Majorana Collaboration is constructing an ultra-low background, modular high-purity Ge detector array to search for this decay in 76Ge. Located at the 4850-ft level of the Sanford Underground Research Facility, the Demonstrator detector assembly has the goal to show that it is possible to achieve background rates necessary for future ton-scale experiments. The talk will give a short introduction to the experiment, an overview of the achievements made in detector construction, data analysis and simulation. After the first commissioning phase last year with more than half of the detectors in their final configuration, the current status of the Demonstrator will be presented in this talk as well as plans for the future. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  15. Constraining neutrino mass from neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Dev, P. S. Bhupal; Goswami, Srubabati; Mitra, Manimala; Rodejohann, Werner

    2013-11-01

    We study the implications of the recent results on neutrinoless double beta decay (0νββ) from GERDA-I (Ge76) and KamLAND-Zen+EXO-200 (Xe136) and the upper limit on the sum of light neutrino masses from Planck. We show that the upper limits on the effective neutrino mass from Xe136 are stronger than those from Ge76 for most of the recent calculations of the nuclear matrix elements (NMEs). We also analyze the compatibility of these limits with the claimed observation in Ge76 and show that while the updated claim value is still compatible with the recent GERDA limit as well as the individual Xe136 limits for a few NME calculations, it is inconsistent with the combined Xe136 limit for all but one NME. Imposing the most stringent limit from Planck, we find that the canonical light neutrino contribution cannot saturate the current limit, irrespective of the NME uncertainties. Saturation can be reached by inclusion of the right-handed (RH) neutrino contributions in TeV-scale left-right symmetric models with type-II seesaw. This imposes a lower limit on the lightest neutrino mass. Using the 0νββ bounds, we also derive correlated constraints in the RH sector, complimentary to those from direct searches at the LHC.

  16. LUCIFER: Neutrinoless Double Beta decay search with scintillating bolometers

    NASA Astrophysics Data System (ADS)

    Pattavina, Luca; LUCIFER Collaboration

    2011-12-01

    One of the fundamental open questions in elementary particle physics is the value of the neutrino mass and its nature of Dirac or Majorana particle. Neutrinoless double beta decay (DBD0ν) is a key tool for investigating these neutrino properties and for finding answers to the open questions concerning mass hierarchy and absolute scale. Experimental techniques based on the calorimetric approach with cryogenic particle detectors are proved to be suitable for the search of this rare decay, thanks to high energy resolution and large mass of the detectors. One of the main issues to access an increase of the experimental sensitivity is strictly related to background reduction, trying to perform possibly a zero background experiment. The LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) project, funded by the European Research Council, aims at building a background-free DBD0ν experiment, with a discovery potential comparable with the present generation experiments. The idea of LUCIFER is to measure, simultaneously, heat and scintillation light with ZnSe bolometers. Detector features and operational procedures are reviewed. The expected performances and sensitivity are also discussed.

  17. LUCIFER: scintillating bolometers for neutrinoless double-beta decay searches

    NASA Astrophysics Data System (ADS)

    Pattavina, Luca

    2014-09-01

    In the field of fundamental particle physics, the nature of the neutrino, if it is a Dirac or a Majorana particle, plays a crucial role not only in neutrino physics, but also in the overall framework of fundamental particle interactions and in cosmology. Neutrinoless double-beta decay (0vDBD) is the key tool for the investigation of this nature. Experimental techniques based on the calorimetric approach with cryogenic particle detectors have demonstrated suitability for the investigation of rare nuclear processes, profiting from excellent energy resolution and scalability to large masses. Unfortunately, the most relevant issue is related to background suppression. In fact, bolometers being fully-active detectors struggle to reach extremely low background level. The LUCIFER project aims to deploy the first array of enriched scintillating bolometers. Thanks to the double read-out - heat and scintillation light produced by scintillating bolometers - a highly efficient background identification and rejection is guaranteed, leading to a background-free experiment. We show the potential of such technology in ZnMoO4 and ZnSe prototypes. We describe the current status of the project, including results of the recent R&D activity.

  18. Sensitivity of NEXT-100 to neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Martín-Albo, J.; Muñoz Vidal, J.; Ferrario, P.; Nebot-Guinot, M.; Gómez-Cadenas, J. J.; Álvarez, V.; Azevedo, C. D. R.; Borges, F. I. G.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L. M. P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Henriques, C. A. O.; Hernando Morata, J. A.; Herrero, V.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Novella, P.; Nygren, D.; Palmeiro, B.; Para, A.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; Yepes-Ramírez, H.

    2016-05-01

    NEXT-100 is an electroluminescent high-pressure xenon gas time projection chamber that will search for the neutrinoless double beta (0 νββ) decay of 136Xe. The detector possesses two features of great value for 0 νββ searches: energy resolution better than 1% FWHM at the Q value of 136Xe and track reconstruction for the discrimination of signal and background events. This combination results in excellent sensitivity, as discussed in this paper. Material-screening measurements and a detailed Monte Carlo detector simulation predict a background rate for NEXT-100 of at most 4 × 10-4 counts keV-1 kg-1 yr-1. Accordingly, the detector will reach a sensitivity to the 0 νββ-decay half-life of 2.8 × 1025 years (90% CL) for an exposure of 100 kg·year, or 6.0 × 1025 years after a run of 3 effective years. [Figure not available: see fulltext.

  19. The SuperNEMO neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Vilela, Cristovao; NEMO Collaboration

    2015-04-01

    SuperNEMO is an experiment currently in the construction phase with the aim of searching for neutrinoless double beta decay, a beyond the standard model lepton number violating process. It employs the same strategy as its predecessor NEMO-3, with a tracker and calorimeter surrounding a thin foil of source isotope. Twenty modules are planned, yielding 100 kg of 82Se as source, with a sensitivity to a half-life of 1026 years. The first module is intended to demonstrate the very stringent radiopurity requirements, with no background counts being expected in the region of interest of the decay for 2.5 years of data taking. It will hold 7 kg of 82Se, giving it a sensitivity to a half-life of 6.5 × 1024 years. The tracking detector is essential for background discrimination and its construction and commissioning are being undertaken in the U.K., primarily at UCL, MSSL (UCL) and The University of Manchester.

  20. Online Data Monitoring for the CUORE Neutrinoless Double-beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Feintzeig, Jacob; Cuore Collaboration

    2015-10-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming bolometric experiment that will search for neutrinoless double-beta decay at Gran Sasso, Italy. Crystals of tellurium dioxide are instrumented with neutron transmutation doped (NTD) thermistors to observe the heat pulse caused by a double beta decay event. Currently under construction, CUORE will contain 988 independent bolometers. The CUORE-0 detector, consisting of the first 52 bolometers, took data from 2013-2015. After briefly reviewing results from a neutrinoless double-beta decay search with CUORE-0, I will outline recent work to improve data analysis and online data quality monitoring for the upcoming CUORE detector.

  1. The MAJORANA DEMONSTRATOR: An R and D project towards a tonne-scale germanium neutrinoless double-beta decay search

    SciTech Connect

    Aalseth, C. E.; Ely, J.; Fast, J. E.; Fuller, E.; Hoppe, E. W.; Keillor, M.; Kouzes, R. T.; Miley, H. S.; Orrell, J. L.; Thompson, R.; Warner, R.; Amman, M.; Bergevin, M.; Chan, Y.-D.; Detwiler, J. A.; Fujikawa, B.; Loach, J. C.; Luke, P. N.; Poon, A. W. P; Prior, G.

    2009-12-17

    The MAJORANA collaboration is pursuing the development of the so-called MAJORANA DEMONSTRATOR. The DEMONSTRATOR is intended to perform research and development towards a tonne-scale germanium-based experiment to search for the neutrinoless double-beta decay of {sup 76}Ge. The DEMONSTRATOR can also perform a competitive direct dark matter search for light WIMPs in the 1-10 GeV/c{sup 2} mass range. It will consist of approximately 60 kg of germanium detectors in an ultra-low background shield located deep underground at the Sanford Underground Laboratory in Lead, SD. The DEMONSTRATOR will also perform background and technology studies, and half of the detector mass will be enriched germanium. This talk will review the motivation, design, technology and status of the Demonstrator.

  2. The MAJORANA DEMONSTRATOR: An R&D project towards a tonne-scale germanium neutrinoless double-beta decay search

    SciTech Connect

    Aalseth, Craig E; Amman, M; Amsbaugh, John F; Avignone, F. T.; Back, Henning O; Barabash, A; Barbeau, Phil; Beene, Jim; Bergevin, M; Bertrand, F; Boswell, M; Brudanin, V; Bugg, William; Burritt, Tom H; Chan, Yuen-Dat; Collar, J I; Cooper, R J; Creswick, R; Detwiler, Jason A; Doe, P J; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H; Elliott, Steven R; Ely, James H; Esterline, James H; Farach, H A; Fast, James E; Fields, N; Finnerty, P; Fujikawa, Brian; Fuller, Erin S; Gehman, Victor; Giovanetti, G K; Guiseppe, Vincente; Gusey, K; Hallin, A L; Hazama, R; Henning, Reyco; Hime, Andrew; Hoppe, Eric W; Hossbach, Todd W; Howe, M A; Johnson, R A; Keeter, K; Keillor, Martin E; Keller, C; Kephart, Jeremy D; Kidd, Mary; Kochetov, Oleg; Konovalov, S; Kouzes, Richard T; Lesko, Kevin; Leviner, L; Loach, J C; Luke, P; MacMullin, S; Marino, Michael G; Mei, Dong-Ming; Miley, Harry S; Miller, M; Mizouni, Leila K; Montoya, A; Myers, A W; Nomachi, Masaharu; Odom, Brian; Orrell, John L; Phillips, D; Poon, Alan; Prior, Gersende; Qian, J; Radford, D C; Rielage, Keith; Robertson, R G. H.; Rodriguez, Larry; Rykaczewski, Krzysztof P; Schubert, Alexis G; Shima, T; Shirchenko, M; Strain, J; Thomas, K; Thompson, Robert C; Timkin, V; Tornow, W; Van Wechel, T D; Vanyushin, I; Vetter, Kai; Warner, Ray A; Wilkerson, J; Wouters, Jan; Yakushev, E; Young, A; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C L; Zimmerman, S

    2009-12-17

    The MAJORANA collaboration is pursuing the development of the so-called MAJORANA DEMONSTRATOR. The DEMONSTRATOR is intended to perform research and development towards a tonne-scale germanium-based experiment to search for the neutrinoless double-beta decay of 76Ge. The DEMONSTRATOR can also perform a competitive direct dark matter search for light WIMPs in the 1-10GeV/c2 mass range. It will consist of approximately 60 kg. of germanium detectors in an ultra-low background shield located deep underground at the Sanford Underground Laboratory in Lead, SD. The DEMONSTRATOR will also perform background and technology studies, and half of the detector mass will be enriched germanium. This talk will review the motivation, design, technology and status of the Demonstrator.

  3. Occupancies of individual orbits, and the nuclear matrix element of the {sup 76}Ge neutrinoless {beta}{beta} decay

    SciTech Connect

    Menendez, J.; Poves, A.

    2009-10-15

    We discuss the variation of the nuclear matrix element (NME) for the neutrinoless double beta (0{nu}{beta}{beta}) decay of {sup 76}Ge when the wave functions are constrained to reproduce the experimental occupancies of the two nuclei involved in the transition. In the interacting shell model description the value of the NME is enhanced about 15% compared to previous calculations, whereas in the QRPA the NME's are reduced by 20%-30%. This diminishes the discrepancies between both approaches. In addition, we discuss the effect of the short-range correlations on the NME in light of the recently proposed parametrizations based on a consistent renormalization of the 0{nu}{beta}{beta} transition operator.

  4. Neutron interactions in the CUORE neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Dolinski, Michelle Jean

    Neutrinoless double beta decay (0nuDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0nuDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0nuDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0nuDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0nuDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0nuDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0nuDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, winch can be produced underground both by (alpha,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE data to set an upper

  5. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    SciTech Connect

    Dolinski, Michelle Jean

    2008-10-01

    Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE

  6. Status and perspective of the GERDA neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Knöpfle, K. T.; Gerda Collaboration

    2012-09-01

    Gerda, the GERManium Detector Array [1], is a new double beta decay experiment which is currently under commissioning in the Infn National Gran Sasso Laboratory (Lngs), Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in 76Ge - in high purity liquid argon supplemented by a water shield. The paper presents the status of the experiment, results from the commissioning, and a summary of planned future activities.

  7. New limit on the neutrinoless double beta decay of /sup 100/Mo

    SciTech Connect

    Krivicich, J.M.

    1988-03-01

    A search for the neutrinoless double beta decay of /sup 100/Mo was conducted using thin Mo films and solid state Si detectors. The experiment has collected 3500 hours of data operating underground in a deep silver mine (3290 M.W.E.). Only one event was found to be consistent with neutrinoless double beta decay. Using this one event, a limit of greater than or equal to 1 x 10/sup 22/ years (1 sigma) is set on the /sup 100/Mo half-life. This is approximately five times larger than the best previous /sup 100/Mo limit.

  8. Neutrinoless double beta decay in type I+II seesaw models

    NASA Astrophysics Data System (ADS)

    Borah, Debasish; Dasgupta, Arnab

    2015-11-01

    We study neutrinoless double beta decay in left-right symmetric extension of the standard model with type I and type II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this model. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for type I and type II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both type I and type II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the model including both heavy and light neutrino masses from the requirement of keeping the new physics contribution to neutrinoless double beta decay amplitude below the upper limit set by the GERDA experiment and also satisfying bounds from lepton flavor violation, cosmology and colliders.

  9. Nuclear structure relevant to neutrinoless double beta decay candidate {sup 130}Te and other recent results

    SciTech Connect

    Kay, B. P.

    2013-12-30

    We have undertaken a series of single-nucleon and pair transfer reaction measurements to help constrain calculations of the nuclear matrix elements for neutrinoless double beta decay. In this talk, a short overview of measurements relevant to the {sup 130}Te→{sup 130}Xe system is given. Brief mention is made of other recent and forthcoming results.

  10. Disentangling effects of mechanisms that could contribute to the neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Horoi, Mihai; Neacsu, Andrei

    2015-10-01

    Neutrinoless double-beta decay, if observed, would signal physics beyond the Standard Model that could be discovered at energies significantly lower than those at which the relevant degrees of freedom could be excited. Therefore, it could be challenging to further use the neutrinoless double-beta decay observations to distinguish between many beyond Standard Model competing mechanisms to this process. Accurate nuclear structure calculation of the nuclear matrix elements necessary to analyze the decay rates could be helpful to narrow down the list of competing mechanisms, and to better identify the more exotic properties of the neutrinos. We will present information that one can get from the angular and energy distribution of the emitted electron assuming that the right-handed currents exist. Support from U.S. NSF Grant PHY-1404442 and DOE Grant DE-SC0008529 is acknowledged.

  11. Neutrinoless Double Beta Decay with CUORE-0: Physics Results and Detector Performance

    NASA Astrophysics Data System (ADS)

    Canonica, L.

    2016-08-01

    The CUORE-0 experiment searches for neutrinoless double beta decay in ^{130}Te. It consists of an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK, with a total mass of about 39 kg of TeO_2. CUORE-0 has been built to test the performance of the upcoming CUORE experiment and represents the largest ^{130}Te bolometric setup currently in operation. This experiment has been running in the Gran Sasso National Laboratory, Italy, since March 2013. We report the results of a search for neutrinoless double beta decay in 9.8 kg years ^{130}Te exposure, which allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background rate and energy resolution are also reported.

  12. Analysis of mechanisms that could contribute to neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Horoi, Mihai; Neacsu, Andrei

    2016-06-01

    Neutrinoless double-beta decay is a beyond the Standard Model process that would indicate that neutrinos are Majorana fermions, and the lepton number is not conserved. It could be interesting to use the neutrinoless double-beta decay observations to distinguish between several beyond Standard Model mechanisms that could contribute to this process. Accurate nuclear structure calculations of the nuclear matrix elements necessary to analyze the decay rates could be helpful to narrow down the list of contributing mechanisms. We investigate the information one can get from the angular and energy distribution of the emitted electrons and from the half-lives of several isotopes, assuming that the right-handed currents exist. For the analysis of these distributions, we calculate the necessary nuclear matrix elements using shell model techniques, and we explicitly consider interference terms.

  13. Neutrinoless Double Beta Decay with CUORE-0: Physics Results and Detector Performance

    NASA Astrophysics Data System (ADS)

    Canonica, L.

    2016-01-01

    The CUORE-0 experiment searches for neutrinoless double beta decay in ^{130} Te. It consists of an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK, with a total mass of about 39 kg of TeO_2 . CUORE-0 has been built to test the performance of the upcoming CUORE experiment and represents the largest ^{130} Te bolometric setup currently in operation. This experiment has been running in the Gran Sasso National Laboratory, Italy, since March 2013. We report the results of a search for neutrinoless double beta decay in 9.8 kg years ^{130} Te exposure, which allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background rate and energy resolution are also reported.

  14. Pion dominance in R-parity violating supersymmetry induced neutrinoless double beta decay

    SciTech Connect

    Faessler, Amand; Gutsche, Thomas; Simkovic, Fedor; Kovalenko, Sergey

    2008-06-01

    At the quark level there are basically two types of contributions of R-parity violating supersymmetry (Re{sub p} SUSY) to neutrinoless double beta decay: the short-range contribution involving only heavy virtual superpartners and the long-range one with the virtual squark and neutrino. Hadronization of the effective operators, corresponding to these two types of contributions, may in general involve virtual pions in addition to close on-mass-shell nucleons. From the previous studies it is known that the short-range contribution is dominated by the pion exchange. In the present paper we show that this is also true for the long-range Re{sub p} SUSY contribution. Therefore, we conclude that the Re{sub p} SUSY contributes to the neutrinoless double beta decay dominantly via charged pion exchange between the decaying nucleons.

  15. CALDER: neutrinoless double-beta decay identification in TeO bolometers with kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Battistelli, E. S.; Bellini, F.; Bucci, C.; Calvo, M.; Cardani, L.; Casali, N.; Castellano, M. G.; Colantoni, I.; Coppolecchia, A.; Cosmelli, C.; Cruciani, A.; de Bernardis, P.; Di Domizio, S.; D'Addabbo, A.; Martinez, M.; Masi, S.; Pagnanini, L.; Tomei, C.; Vignati, M.

    2015-08-01

    Next-generation experiments searching for neutrinoless double-beta decay must be sensitive to a Majorana neutrino mass as low as 10. CUORE , an array of 988 TeO bolometers being commissioned at Laboratori Nazionali del Gran Sasso, features an expected sensitivity of 50-130 at 90 % C.L. The background is expected to be dominated by radioactivity, and can be in principle removed by detecting the small amount of Cherenkov light emitted by the signal. The Cryogenic wide-Area Light Detectors with Excellent Resolution project aims at developing a small prototype experiment consisting of TeO bolometers coupled to high-sensitivity light detectors based on kinetic inductance detectors. The R&D is focused on the light detectors in view of the implementation in a next-generation neutrinoless double-beta decay experiment.

  16. Are massive Majorana neutrinos canceling each other in neutrinoless double-. beta. decay

    SciTech Connect

    Vergados, J.D.

    1983-12-01

    The possibility of various massive Majorana neutrinos canceling each other in neutrinoless double-..beta.. decay is examined. It is shown that if all neutrino eigenmasses are less than 10 MeV such a cancellation persists in the hadronic medium if initially present at the elementary (gauge) level. The same is true for neutrino mass greater than 10 GeV. In all other cases, such a cancellation will require a conspiracy between particle and nuclear physics.

  17. New physics effects on neutrinoless double beta decay from right-handed current

    NASA Astrophysics Data System (ADS)

    Ge, Shao-Feng; Lindner, Manfred; Patra, Sudhanwa

    2015-10-01

    We study the impact of new physics contributions to neutrinoless double beta decay arising from right-handed current in comparison with the standard mechanism. If the light neutrinos obtain their masses from Type-II seesaw within left-right symmetric model, where the Type-I contribution is suppressed to negligible extent, the right-handed PMNS matrix is the same as its left-handed counterpart, making it highly predictable and testable at next-generation experiments. It is very attractive, especially with recent cosmological constraint favoring the normal hierarchy under which the neutrinoless double beta decay is too small to be observed unless new physics appears as indicated by the recent diboson excess observed at ATLAS. The relative contributions from left- and right-handed currents can be reconstructed with the ratio between lifetimes of two different isotopes as well as the ratio of nuclear matrix elements. In this way, the theoretical uncertainties in the calculation of nuclear matrix elements can be essentially avoided. We also discuss the interplay of neutrinoless double beta decay measurements with cosmology, beta decay, and neutrino oscillation.

  18. The MAJORANA DEMONSTRATOR: A search for neutrinoless double-beta decay of ⁷⁶Ge

    SciTech Connect

    Xu, W.; Abgrall, N.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y. -D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Efremenko, Yu; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Poon, A. W.P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Yakushev, E.; Yu, C. -H.; Yumatov, V.

    2015-05-01

    Neutrinoless double-beta (0νββ) decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The Majorana Collaboration is constructing the MAJORANA DEMONSTRATOR, with a total of 40-kg Germanium detectors, to search for the 0νββ decay of ⁷⁶Ge and to demonstrate a background rate at or below 3 counts/(ROI•t•y) in the 4 keV region of interest (ROI) around the 2039 keV Q-value for ⁷⁶Ge 0νββ decay. In this paper, we discuss the physics of neutrinoless double beta decay and then focus on the MAJORANA DEMONSTRATOR, including its design and approach to achieve ultra-low backgrounds and the status of the experiment.

  19. The MAJORANA DEMONSTRATOR: A search for neutrinoless double-beta decay of ⁷⁶Ge

    DOE PAGESBeta

    Xu, W.; Abgrall, N.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; et al

    2015-05-01

    Neutrinoless double-beta (0νββ) decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The Majorana Collaboration is constructing the MAJORANA DEMONSTRATOR, with a total of 40-kg Germanium detectors,more » to search for the 0νββ decay of ⁷⁶Ge and to demonstrate a background rate at or below 3 counts/(ROI•t•y) in the 4 keV region of interest (ROI) around the 2039 keV Q-value for ⁷⁶Ge 0νββ decay. In this paper, we discuss the physics of neutrinoless double beta decay and then focus on the MAJORANA DEMONSTRATOR, including its design and approach to achieve ultra-low backgrounds and the status of the experiment.« less

  20. Shell-model calculation of neutrinoless double-β decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Sen'kov, R. A.; Horoi, M.

    2016-04-01

    In this article we present an extension of our recent Rapid Communication [Phys. Rev. C 90, 051301(R) (2014)], 10.1103/PhysRevC.90.051301 where we calculate the nuclear matrix elements for neutrinoless double-β decay of 76Ge. For the calculations we use a novel method that has perfect convergence properties and allows one to obtain the nonclosure nuclear matrix elements for 76Ge with a 1% accuracy. We present a new way to calculate the optimal closure energy; using this energy with the closure approximation provides the most accurate closure nuclear matrix elements. In addition, we present a new analysis of the heavy-neutrino-exchange nuclear matrix elements, and we compare occupation probabilities and Gamow-Teller strength with experimental data.

  1. Calculation of two-neutrino double beta decay half-lives of 76Ge, 82Se, 96Zr and 100Mo nuclei for the 0+ → 0+ transition

    NASA Astrophysics Data System (ADS)

    Aytekin, Hüseyin; Yılmaz, Alaaddin

    2015-06-01

    We calculated the half-lives of two-neutrino double beta decay (2ν β β ) of 76Ge, 82Se, 96Zr and 100Mo nuclei for the 0+ ↦ 0+ transition. Quasiparticle random phase approximation (QRPA) was used by considering the charge-exchange spin-spin interactions among the nucleons by considering both particle-hole (p-h) and particle-particle (p-p) channels in the separable form. Calculations were performed for the spherical form of the nuclei.

  2. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    NASA Astrophysics Data System (ADS)

    Moggi, N.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Datskov, V.; Dell'oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.

    2015-03-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.

  3. AXEL: High pressure xenon gas Time Projection Chamber for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Pan, Sheng

    2016-05-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use proportional scintillation mode with a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used reduce background. The project is in a R&D phase, and we report current status of our prototype chamber with 10 L and 8 bar Xe gas. We also present the results of the photon detection efficiency measurement and the linearity test of silicon photomultiplier(SiPM).

  4. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    DOE PAGESBeta

    Moggi, N.; Artusa, D. R.; F. T. Avignone; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; et al

    2015-03-24

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.

  5. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    SciTech Connect

    Moggi, N.; Artusa, D. R.; F. T. Avignone; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Datskov, V.; Dell’oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Morganti, S.; Napolitano, T.; Nisi, S.; C. Nones; Norman, E. B.; Nucciotti, A.; O’Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.; Fabbri, F.; Giacomelli, P.

    2015-03-24

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.

  6. Majorana phases, CP violation, sterile neutrinos and neutrinoless double-beta decay

    SciTech Connect

    Babič, Andrej; Šimkovic, Fedor

    2013-12-30

    CP violation plays a crucial role in the generation of the baryon asymmetry in the Universe. Within this context we investigate the possibility of CP violation in the lepton sector caused by Majorana neutrino mixing. Focus is put on the model including 1 sterile neutrino. Both cases of normal and inverted neutrino mass spectrum are considered. We address the question whether the Majorana phases can be measured in the neutrinoless double-beta decay experiments with sensitivity to the effective Majorana neutrino mass of the order of 10{sup −2} eV.

  7. Ultra-low gamma-ray measurement system for neutrinoless double beta decay.

    PubMed

    Kang, W G; Choi, J H; Jeon, E J; Lee, J I; Kim, H J; Kim, S K; Kim, Y D; Lee, J H; Ma, K J; Myung, S S; So, J H

    2013-11-01

    An experiment for the detection of 0νβ(+)/EC and 0νEC/EC in 92Mo nuclei has been carried out with a scintillating crystal, CaMoO4, in coincidence with the HPGe detector. We study the background events inside the event selection window for 0ν β(+)/EC decays of CaMoO4 detector. For 51.2 days of data taking period, we didn't observe any event in the neutrinoless EC/EC decay event window. The (92)Mo 0νβ(+)/EC decay half-life limit was set to 0.61×10(20) years with a 90% confidence by method of Feldman and Cousins. This ultra-low gamma ray measurement utilizing coincidence technique can be used for the resonant EC/EC decay process of some nuclei which is potentially important for neutrinoless double beta decay process. PMID:23726518

  8. The Majorana Double Beta Decay Experiment: Present Status

    SciTech Connect

    Aguayo, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Beene, Jim; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, C. D.; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips II, D. G.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

    2013-06-01

    The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale 76Ge neutrinoless double-beta decay experiment, an R&D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator

  9. Low-lying levels of 76Ge, a candidate for neutrinoless double- β decay

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; B. P. Crider Team; E. E. Peters Team; F. M. Prados-Este'vez Team; M. T. McEllistrem Team; S. W. Yates Team

    2015-10-01

    The low-spin structure of 76Ge was studied at the University of Kentucky with the (n,n' γ) reaction. This nucleus is a parent in double- β decay and is also a rare example of a nucleus to exhibit rigid triaxial deformation in the low-lying states. Excitation function measurements performed with neutrons from 1.6 to 3.7 MeV helped determine the threshold for the γ rays and hence their placement in the level scheme. Lifetimes, spins,multipolarities, and branching ratios were obtained from angular distributions measured at neutron energies of 3.0 and 3.5 MeV. New levels identified around 2 MeV will give insight to the nuclear structure aspects of 76Ge. It is also important to identify any γ rays around 2039 keV, as the experimental signature for neutrinoless double- β decay is a weak peak at this energy. In a recent study with 4.9-MeV neutrons, a reported 2039-keV γ ray from the 3952-keV level was not observed. However, definitely a new level at 3147 keV with 2584- and 2038-keV γ rays to the 21+ and 22+ states, respectively was established. These findings indicate that backgrounds in the search for the neutrinoless double- β decay of 76Ge may be more complex. This material is based upon work supported by the U.S. National Science Foundation under Grant No. PHY-1305801.

  10. The COBRA experiment - Status and prospects on the search of neutrinoless double beta-decay

    NASA Astrophysics Data System (ADS)

    Zatschler, S.

    2015-10-01

    The Cadmium-Zinc-Telluride 0-ν Double Beta Research Apparatus (COBRA) [1] is a next-generation experiment searching for the existence of neutrinoless double beta-decay (0νββ-decay). The observation of 0νββ-decay would be an unambiguous sign for physics beyond the Standard Model such as lepton number violating processes and would prove the Majorana character of neutrinos. Furthermore, the study of 0νββ-decay could probe the absolute neutrino mass and allows for the identification of the neutrino mass hierarchy realized in nature assuming light Majorana neutrino exchange. Currently a demonstrator setup at the underground facility LNGS (Italy) built of 4×4×4 coplanar grid (CPG) detectors collects high quality low background physics data with FADC pulse shape sampling. The detectors are made of natural abundant CdZnTe (CZT), which is a commercially available room temperature semiconductor. It contains several double beta isotopes, the most promising of which is 116Cd with a Q-value of 2813.5 keV - which is well above the highest naturally occurring prominent γ-lines.

  11. The COBRA experiment – Status and prospects on the search of neutrinoless double beta-decay

    SciTech Connect

    Zatschler, S.

    2015-10-28

    The Cadmium-Zinc-Telluride 0-ν Double Beta Research Apparatus (COBRA) [1] is a next-generation experiment searching for the existence of neutrinoless double beta-decay (0νββ-decay). The observation of 0νββ-decay would be an unambiguous sign for physics beyond the Standard Model such as lepton number violating processes and would prove the Majorana character of neutrinos. Furthermore, the study of 0νββ-decay could probe the absolute neutrino mass and allows for the identification of the neutrino mass hierarchy realized in nature assuming light Majorana neutrino exchange. Currently a demonstrator setup at the underground facility LNGS (Italy) built of 4×4×4 coplanar grid (CPG) detectors collects high quality low background physics data with FADC pulse shape sampling. The detectors are made of natural abundant CdZnTe (CZT), which is a commercially available room temperature semiconductor. It contains several double beta isotopes, the most promising of which is {sup 116}Cd with a Q-value of 2813.5 keV – which is well above the highest naturally occurring prominent γ-lines.

  12. Search for Neutrinoless Double-Beta Decay of with CUORE-0

    DOE PAGESBeta

    Alfonso, K.; Artusa, D.  R.; F. T. Avignone; Azzolini, O.; Balata, M.; Banks, T.  I.; Bari, G.; Beeman, J.  W.; Bellini, F.; Bersani, A.; et al

    2015-09-03

    We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5.1 ± 0.3 keV FWHM and 0.058 ± 0.004 (stat.) ± 0:002 (syst.) counts/(keV kg yr), respectively. The median 90% C.L. lower-limit sensitivity of the experiment is 2.9 x 1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T0$_1$1/2 > 2.7more » x 1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T0$_1$1/2 > 4.0 x 1024 yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, mββ < 270 - 760 meV.« less

  13. Search for Neutrinoless Double-Beta Decay of Te130 with CUORE-0

    DOE PAGESBeta

    Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; et al

    2015-09-03

    We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5:1± 0:3 keV FWHM and 0:058 ± 0:004 (stat) ± 0:002 (syst) counts / (keV kg yr), respectively. The median 90% C.L. lower-limit half-life sensitivity of the experiment is 2:9x1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T0ν1/2 > 2.7more » x 1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T0ν1/2 > 4.0 x 1024 yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Lastly, using a range of nuclear matrix element estimates we interpret this as a limit on the e ective Majorana neutrino mass, mββ < 270 -760 meV.« less

  14. Status Update of the Majorana Demonstrator Neutrinoless Double Beta Decay Experiment

    SciTech Connect

    Gruzko, Julieta; Rielage, Keith Robert; Xu, Wenqin; Elliott, Steven Ray; Massarczyk, Ralph; Goett, John Jerome III; Chu, Pinghan

    2015-11-10

    Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The Majorana Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in 76Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

  15. Search for Neutrinoless Double-Beta Decay of 130Te with CUORE-0

    NASA Astrophysics Data System (ADS)

    Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Dell'Oro, S.; Deninno, M. M.; di Domizio, S.; di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.; Cuore Collaboration

    2015-09-01

    We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5.1 ±0.3 keV FWHM and 0.058 ±0.004 (stat)±0.002 (syst)counts /(keV kg yr ) , respectively. The median 90% C.L. lower-limit half-life sensitivity of the experiment is 2.9 ×1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T1/2 0 ν>2.7 ×1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T1/2 0 ν>4.0 ×1024 yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, mβ β<270 - 760 meV .

  16. Fast-neutron-induced potential background near the Q value of neutrinoless double-β decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Tornow, W.; Bhike, Megha; Fallin, B.; Krishichayan

    2016-01-01

    The 76Ge (n,p)76Ga reaction and the subsequent β decay of 76Ga to 76Ge has been used to excite the 3951.89-keV state of 76Ge , which decays by the emission of a 2040.70-keV γ ray. Using high-purity germanium detectors, the associated pulse-height signal may be undistinguishable from the potential signal produced in neutrinoless double-β decay of 76Ge with its Q value of 2039.0 keV. At 20-MeV neutron energy the production cross section of the 2040.70-keV γ ray is approximately 0.1 mb.

  17. First results on neutrinoless double beta decay of 130Te with the calorimetric CUORICINO experiment

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Artusa, D. R.; Avignone, F. T.; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J. W.; Brofferio, C.; Bucci, C.; Capelli, S.; Capozzi, F.; Carbone, L.; Cebrian, S.; Cremonesi, O.; Creswick, R. J.; de Waard, A.; Farach, H. A.; Fascilla, A.; Fiorini, E.; Frossati, G.; Giuliani, A.; Gorla, P.; Haller, E. E.; McDonald, R. J.; Morales, A.; Norman, E. B.; Nucciotti, A.; Olivieri, E.; Palmieri, E.; Pasca, E.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Pobes, C.; Previtali, E.; Pyle, M.; Risegari, L.; Rosenfeld, C.; Sangiorgio, S.; Sisti, M.; Smith, A. R.; Torres, L.; Ventura, G.

    2004-04-01

    The first results are reported on the limit for neutrinoless double decay of 130Te obtained with the new bolometric experiment CUORICINO. The set-up consists of 44 cubic crystals of natural TeO2, 5 cm on the side and 18 crystals of 3×3×6 cm3. Four of these latter crystals are made with isotopically enriched materials: two in 128Te and two others in 130Te. With a sensitive mass of ∼40 kg, our array is by far the most massive running cryogenic detector to search for rare events. The array is operated at a temperature of ∼10 mK in a dilution refrigerator under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. The counting rate in the region of neutrinoless double beta decay is ∼0.2 counts keV-1 kg-1 y-1, among the lowest in this type of experiment. No evidence for neutrinoless double beta decay is found with the present statistics obtained in about three months with a live time of 72%. The corresponding lower limit for the lifetime of this process is of 5.5×1023 years at 90% C.L. The corresponding limit for the effective neutrino mass ranges between 0.37 to 1.9 eV depending on the theoretically calculated nuclear matrix elements used. This constraint is the most restrictive one except those obtained with Ge diodes, and is comparable to them.

  18. First results on neutrinoless double beta decay of Te-130 with the calorimetric cuoricino experiment

    SciTech Connect

    Arnaboldi, C.; Artusa, D.R.; Avignone, F.T.; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J.W.; Brofferio, C.; Bucci, C.; Capelli, S.; Capozzi, F.; Carbone, L.; Cebrian, S.; Cremonesi, O.; Creswick, R.J.; de Waard, A.; Farach, H.A.; Fascilla, A.; Fiorini, E.; Frossati, G.; Giuliani, A.; Gorla, P.; Haller, E.E.; McDonald, R.J.; Morales, A.; Norman, E.B.; Nucciotti, A.; Olivieri, E.; Palmieri, E.; Pasca, E.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Pobes, C.; Previtali, E.; Pyle, M.; Risegari, L.; Rosenfeld, C.; Sangiorgio, S.; Sisti, M.; Smith, A.R.; Torres, L.; Ventura, G.

    2003-12-04

    The first results are reported on the limit for neutrinoless double decay of {sup 130}Te obtained with the new bolometric experiment CUORICINO. The set-up consists of 44 cubic crystals of natural TeO{sub 2}, 5 cm on the side and 18 crystals of 3 x 3 x 6 cm{sup 3}. Four of these latter crystals are made with isotopically enriched materials: two in {sup 128}Te and two others in {sup 130}Te . With a sensitive mass of {approx}40 kg, our array is by far the most massive running cryogenic detector to search for rare events. The array is operated at a temperature of {approx}10 mK in a dilution refrigerator under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. The counting rate in the region of neutrinoless double beta decay is {approx}0.2 counts keV{sup -1} kg{sup -1} year{sup -1}, among the lowest in this type of experiment. No evidence for neutrinoless double beta decay is found with the present statistics obtained in about three months with a live time of 72%. The corresponding lower limit for the lifetime of this process is of 5.5 x 10{sup 23} years at 90% C.L. The corresponding limit for the effective neutrino mass ranges between 0.37 to 1.9 eV depending on the theoretically calculated nuclear matrix elements used. This constraint is the most restrictive one except those obtained with Ge diodes, and is comparable to them.

  19. Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of 48Ca with the NEMO-3 detector

    NASA Astrophysics Data System (ADS)

    Arnold, R.; Augier, C.; Bakalyarov, A. M.; Baker, J. D.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Blot, S.; Bongrand, M.; Brudanin, V.; Busto, J.; Caffrey, A. J.; Calvez, S.; Cascella, M.; Cerna, C.; Cesar, J. P.; Chapon, A.; Chauveau, E.; Chopra, A.; Duchesneau, D.; Durand, D.; Egorov, V.; Eurin, G.; Evans, J. J.; Fajt, L.; Filosofov, D.; Flack, R.; Garrido, X.; Gómez, H.; Guillon, B.; Guzowski, P.; Hodák, R.; Huber, A.; Hubert, P.; Hugon, C.; Jullian, S.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lalanne, D.; Lang, K.; Lebedev, V. I.; Lemière, Y.; Le Noblet, T.; Liptak, Z.; Liu, X. R.; Loaiza, P.; Lutter, G.; Mamedov, F.; Marquet, C.; Mauger, F.; Morgan, B.; Mott, J.; Nemchenok, I.; Nomachi, M.; Nova, F.; Nowacki, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P.; Přidal, P.; Ramachers, Y. A.; Remoto, A.; Reyss, J. L.; Richards, B.; Riddle, C. L.; Rukhadze, E.; Rukhadze, N. I.; Saakyan, R.; Salazar, R.; Sarazin, X.; Shitov, Yu.; Simard, L.; Šimkovic, F.; Smetana, A.; Smolek, K.; Smolnikov, A.; Söldner-Rembold, S.; Soulé, B.; Štekl, I.; Suhonen, J.; Sutton, C. S.; Szklarz, G.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, Vl. I.; Tretyak, V. I.; Umatov, V. I.; Vanushin, I.; Vilela, C.; Vorobel, V.; Waters, D.; Zhukov, S. V.; Žukauskas, A.; NEMO-3 Collaboration

    2016-06-01

    The NEMO-3 experiment at the Modane Underground Laboratory investigates the double-beta decay of 48Ca. Using 5.25 yr of data recorded with a 6.99 g sample of 48Ca, approximately 150 double-beta decay candidate events are selected with a signal-to-background ratio greater than 3. The half-life for the two-neutrino double-beta decay of 48Ca is measured to be T1/2 2 ν=[6. 4-0.6+0.7(stat)-0.9 +1.2(syst ) ]×1 019 yr . A search for neutrinoless double-beta decay of 48Ca yields a null result, and a corresponding lower limit on the half-life is found to be T1/2 0 ν>2.0 ×1 022 yr at 90% confidence level, translating into an upper limit on the effective Majorana neutrino mass of ⟨mβ β⟩<6.0 - 26 eV , with the range reflecting different nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right-handed currents.

  20. MOON for a next-generation neutrino-less double-beta decay experiment: Present status and perspective

    SciTech Connect

    Shima, T.; Doe, P.J.; Ejiri, H.; Elliot, S.R.; Engel, J.; Finger, M.; Finger, M.; Fushimi, K.; Gehman, V.M.; Greenfield, M.B.; Hazama, R.; /Hiroshima U. /NIRS, Chiba

    2008-01-01

    The performance of the MOON detector for a next-generation neutrino-less double-beta decay experiment was evaluated by means of the Monte Carlo method. The MOON detector was found to be a feasible solution for the future experiment to search for the Majorana neutrino mass in the range of 100-30 meV.

  1. Inelastic neutron scattering cross sections for 76Ge relevant to background in neutrinoless double-β decay experiments

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Peters, E. E.; Allmond, J. M.; McEllistrem, M. T.; Prados-Estévez, F. M.; Ross, T. J.; Vanhoy, J. R.; Yates, S. W.

    2015-09-01

    The experimental signature in searches for the neutrinoless double-β decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Inelastic scattering reactions with neutrons from muon-induced interactions and (α ,n ) reactions in the surrounding materials or in the detector can provide contributions to the background. We have measured the production cross sections for γ rays from the 76Ge(n ,n'γ ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the cross sections of a previously known 2040.7-keV γ ray from the 3952-keV level in 76Ge are rather small, we find that a larger contribution arises from a 2037.5-keV γ ray which is attributed to a newly identified level at 3147 keV in 76Ge. A third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double-β decay searches is more complex than was previously thought.

  2. The search for Majorana neutrinos with neutrinoless double beta decays: From CUORICINO to LUCIFER experiment

    SciTech Connect

    Bellini, F.

    2012-11-20

    The study of neutrino properties is one of the fundamental challenges in particle physics nowadays. Fifty years of investigations established that neutrinos are massive but the absolute mass scale has not yet been measured. Moreover its true nature is still unknown. Is the neutrino its own antiparticle (thus violating the lepton number) as proposed by Majorana in 1937? The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay (0{nu}{beta}{beta}), a very rare spontaneous nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the theoretical framework of Majorana's neutrino, a presentation of experimental challenges posed by 0{nu}{beta}{beta} search will be given as well as an overview of present status and future perpectives of experiments.

  3. The neutrinoless double beta decay experiment COBRA: Status and future plans

    NASA Astrophysics Data System (ADS)

    Martin, Jerrad

    2009-10-01

    The COBRA experiment uses Cadmium Zinc Telluride (CZT) room-temperature solid-state detectors to search for neutrinoless double beta decays of the isotope ^116Cd as well as for rare decays from several other Cd and Te isotopes. A prototype experiment is currently taking data in the Gran Sasso underground laboratory. In this contribution, recent results from the prototype will be presented. Furthermore, the on-going detector R&D will be described and two detector options for a large-scale experiment made of 420 kg of CZT detectors will be discussed. The first option uses ``calorimetric coplanar grid detector units". Alternatively, finely pixelated detectors may be used with pixel pitches of between 200 and 350 microns. The pixelated detectors would afford the possibility of tracking beta particles inside the detector and distinguishing them from background events.

  4. An update on the neutrinoless double beta decay search at Cuoricino

    NASA Astrophysics Data System (ADS)

    Gutierrez, Thomas D.

    2004-10-01

    We present a status report on the neutrinoless double beta (0ν2β) decay search efforts at Cuoricino, a bolometric experiment located at the Gran Sasso Laboratory in Italy. In particular, we provide an update on the ongoing hardware development and parallel analysis efforts at LBNL. Cuoricino consists of a single tower of 62 TeO2 crystals ( ˜ 40 kg), which serve as both the source and detector for the 0ν2β decays. We also discuss the proposed CUORE (Cryogenic Underground Observatory for Rare Events) experiment. Similar in concept to Cuoricino, CUORE will consist of 1000 TeO2 crystals having a total mass of approximately 760 kg. CUORE will provide more statistics and, along with various anticipated technical improvements, higher sensitivity to 0ν2β decays than Cuoricino. This work is supported by the US Department of Energy.

  5. The search for Majorana neutrinos with neutrinoless double beta decays: From CUORICINO to LUCIFER experiment

    NASA Astrophysics Data System (ADS)

    Bellini, F.

    2012-11-01

    The study of neutrino properties is one of the fundamental challenges in particle physics nowadays. Fifty years of investigations established that neutrinos are massive but the absolute mass scale has not yet been measured. Moreover its true nature is still unknown. Is the neutrino its own antiparticle (thus violating the lepton number) as proposed by Majorana in 1937? The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay (0νββ), a very rare spontaneous nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the theoretical framework of Majorana's neutrino, a presentation of experimental challenges posed by 0νββ search will be given as well as an overview of present status and future perpectives of experiments.

  6. Lucifer:. AN Experimental Breakthrough in the Search for Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Dafinei, I.; Ferroni, F.; Giuliani, A.; Pirro, S.; Previtali, E.

    2011-03-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of the scintillating bolometers. These devices promise a very efficient rejection of the a background, opening the way to a virtually background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced and the sensitivity and the prospects related to this project will be discussed.

  7. LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Nones, C.; Lucifer Group

    2011-08-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

  8. Anti-Reflective Coatings R&D for Next Generation Neutrinoless Double Beta Experiments

    NASA Astrophysics Data System (ADS)

    Leder, Alexander; Cuore Collaboration

    2016-03-01

    The Cyogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic source=detector experiment designed to search for the Neutrinoless Double Beta Decay (0 νββ) of 130Te. CUORE currently utilizes a single phonon readout channel per crystal; adding a second channel for scintillation or Cherenkov light would improve particle identification for actively rejecting background events. This light would be collected via semiconductor wafers covered with anti-reflective coatings. These coatings maximize light absorption. In this talk, I will discuss the coating optimization regarding material and structure, and its implications for designing the next generation CUORE-style experiment. In addition, I will discuss projections for possible sensitivities of next generation 0 νββ searches that use dual channel light-phonon readouts.

  9. Bilepton contributions to the neutrinoless double beta decay in the economical 3-3-1 model

    SciTech Connect

    Soa, D. V. Dong, P. V. Huong, T. T.; Long, H. N.

    2009-05-15

    A new bound of the mixing angle between charged gauge bosons (the standard-model W and the bilepton Y) in the economical 3-3-1 model is given. Possible contributions of the charged bileptons to the neutrinoless double beta (({beta}{beta}){sub 0{nu}}) decay are discussed. We show that the ({beta}{beta}){sub 0{nu}} decay in this model is due to both the Majorana {sub L} and Dirac {sub D} neutrino masses. If the mixing angle is in the range of the ratio of neutrino masses {sub L}/{sub D}, the Majorana and Dirac masses are comparable to each other and both may give the main contribution to the decay. As a result, constraints on the bilepton mass are given.

  10. Upgrading KamLAND-Zen for improved sensitivity to neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Krupczak, Emmett; KamLAND-Zen Collaboration

    2015-10-01

    KamLAND is a 1 kton liquid scintillator antineutrino detector located underground in Kamioka, Japan. The KamLAND-Zen experiment began in 2011, using KamLAND to search for neutrinoless double-beta decay (0 νββ). This process, if observed, would indicate that neutrinos are their own antiparticle and thus are Majorana fermions, a discovery that could help explain the matter-antimatter discrepancy in our universe. Currently, KamLAND-Zen is one of the most sensitive experiments to 0 νββ . In order to improve upon the present limits for 0 νββ , KamLAND is undergoing a series of upgrades to reduce background. This includes the construction of a new inner nylon chamber (``mini-balloon''). The current results and design considerations for the mini-balloon will be discussed.

  11. Searching for neutrinoless double beta decay of Te-130 with CUORE bolometers

    NASA Astrophysics Data System (ADS)

    Han, Ke; Cuore Collaboration

    2015-10-01

    The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will search for neutrinoless double beta decay of Te-130. CUORE large-mass bolometer array will consist of 988 tellurium oxide bolometer modules and a total of 206 kg of Te-130 in one single cryostat at 10 mK. It will be sensitive to an effective Majorana neutrino mass of 50-130 meV and is one of the most sensitive experiments under construction. The detector and the cryostat are in an advanced stage of installation and is expected to start operation by the end of 2015. Recents results from CUORE-0, a prototype experiment to CUORE, have validated the performance and background predictions of TeO2 bolometer arrays. In this talk, we will present the latest results from CUORE-0, the construction status, as well as sensitivity projection of CUORE. On behalf of the CUORE Collaboration.

  12. Bounds for Neutrinoless Double Beta Decay in SO(10) Inspired Seesaw Models

    NASA Astrophysics Data System (ADS)

    Buccella, F.; Falcone, D.

    By requiring the lower limit for the lightest right-handed neutrino mass, obtained in the baryogenesis from leptogenesis scenario, and a Dirac neutrino mass matrix similar to the up-quark mass matrix, we predict small values for the νe mass and for the matrix element mee responsible of the neutrinoless double beta decay, mνe around 5×10-3 eV and mee smaller than 10-3 eV, respectively. The allowed range for the mass of the heaviest right-handed neutrino is centered around the value of the scale of B-L breaking in the SO(10) gauge theory with Pati-Salam intermediate symmetry.

  13. Status Update of the MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Vorren, Kristopher; Majorana Collaboration

    2015-04-01

    The MAJORANA collaboration has made significant progress over the past year on the MAJORANA DEMONSTRATOR. The goal of the DEMONSTRATOR is to demonstrate backgrounds low enough to justify building a tonne-scale experiment, establish the feasibility to construct and field modular arrays of Ge detectors, and perform searches for additional physics beyond the standard model. The DEMONSTRATOR is currently being built at the 4850 ft level of the Sanford Underground Research Facility (SURF) in Lead, SD. The first of three custom cryostats, the prototype module, is currently taking data, while assembly and commissioning of the second cryostat, module 1, is ongoing. Hardware fabrication for the third cryostat, module 2, is nearing completion. Combined, module 1 and module 2 will contain 40 kg of Ge detectors with 30 kg enriched to 87 % 76 Ge, the double-beta decaying isotope. An active simulation and analysis campaign is underway for the prototype and module 1 cryostats. This talk will provide an overview and status update on the DEMONSTRATOR. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  14. The AMoRE: Search for neutrinoless double beta decay of {sup 100}Mo

    SciTech Connect

    Park, HyangKyu

    2015-10-28

    The AMoRE (Advanced Mo-based Rare process Experiment) collaboration is using calcium molybdate ({sup dep48}Ca {sup 100}MoO{sub 4}) crystals enriched in {sup 100}Mo and depleted in {sup 48}Ca to search for neutrinoless double-beta decay (DBD) of {sup 100}Mo using at the underground laboratory in Korea. Metallic magnetic calorimeters operating a milliKelvin temperatures are used as temperature sensors to measure heat and light signals from the crystals. The simultaneous and fast detection capabilities for both phonons and photons, and their excellent energy resolution provide powerful methods for identifying DBD signals and rejecting background events, which are mainly due to random coincidences between two uncorrelated two-neutrino-double-beta decays of {sup 100}Mo. The AMoRE-Pilot experiment that is currently underway uses a 1.5 kg, five-element array of {sup dep48}Ca {sup 100}MoO{sub 4} crystals. The ultimate goal is a ∼200 kg array of crystals and a half-life sensitivity of order 10{sup 26} years, which will access the inverted hierarchy region for effective Majorana neutrino masses, i.e., 0.02 to 0.05 eV. In this talk, we present recent progress on the development of low-background calcium molybdate detectors and results from room- and milli-Kelvin temperatures. Sensitivities based on GEANT4 simulations that incorporate measured background are reported.

  15. The AMoRE: Search for neutrinoless double beta decay of 100Mo

    NASA Astrophysics Data System (ADS)

    Park, HyangKyu

    2015-10-01

    The AMoRE (Advanced Mo-based Rare process Experiment) collaboration is using calcium molybdate (dep48Ca 100MoO4) crystals enriched in 100Mo and depleted in 48Ca to search for neutrinoless double-beta decay (DBD) of 100Mo using at the underground laboratory in Korea. Metallic magnetic calorimeters operating a milliKelvin temperatures are used as temperature sensors to measure heat and light signals from the crystals. The simultaneous and fast detection capabilities for both phonons and photons, and their excellent energy resolution provide powerful methods for identifying DBD signals and rejecting background events, which are mainly due to random coincidences between two uncorrelated two-neutrino-double-beta decays of 100Mo. The AMoRE-Pilot experiment that is currently underway uses a 1.5 kg, five-element array of dep48Ca 100MoO4 crystals. The ultimate goal is a ˜200 kg array of crystals and a half-life sensitivity of order 1026 years, which will access the inverted hierarchy region for effective Majorana neutrino masses, i.e., 0.02 to 0.05 eV. In this talk, we present recent progress on the development of low-background calcium molybdate detectors and results from room- and milli-Kelvin temperatures. Sensitivities based on GEANT4 simulations that incorporate measured background are reported.

  16. Neutrino-less Double Beta Decay of {sup 48}Ca-CANDLES

    SciTech Connect

    Kishimoto, T.; Nomachi, M.; Yoshida, S.; Matsuoka, K.; Ichimura, K.; Ito, G.; Yasuda, K.; Kakubata, H.; Miyashita, M.; Takubo, K.; Saka, M.; Seki, K.; Ajimura, S.; Umehara, S.; Nakatani, N.; Tamagawa, Y.; Ogawa, I.; Fushimi, K.; Hazama, R.; Ohsumi, H.

    2011-10-21

    Neutrino-less double beta decay (0{nu}{beta}{beta}) is currently known to be an only experiment to verify whether lepton number is conserved or not. The lepton number non-conservation is the key to create matter dominated universe with CP violation. The so-called leptogenesys scenario presents a way to create the matter dominated universe by these violations. If neutrinos have Majorana mass, transition from a particle to an anti-particle is possible and the left-handed and right-handed neutrinos could have different masses. It is highly likely that the neutrinos are Majorana particles. We have been studying double beta decay of {sup 48}Ca. Our first stage experiment using the ELEGANT VI detector system gave the best lower limit of the half life of 0{nu}{beta}{beta} of {sup 48}Ca. We have been working on CANDLES detector system to sense much longer lifetime region. We have developed techniques to reduce backgrounds. The CADLES detector system was installed at Kamioka underground laboratory. Here I describe a schematic view of the system.

  17. TPC Detectors for Neutrino-less Double-Beta Decay and Dark Matter Searches

    NASA Astrophysics Data System (ADS)

    Goldschmidt, Azriel

    2012-10-01

    Time Projection Chambers (TPCs) are increasingly becoming the particle detector technology of choice for rare event searches such as neutrino-less double beta decays and direct WIMP dark matter interactions. At present time, experiments using xenon-filled TPCs are producing some of the best limits for both of these searches. TPCs offer 3D ionization-track imaging as well as calorimetric energy measurements both of which are important handles for the identification of the rare sought-after events while discarding background events due to cosmic rays or due to radioactive decays in the detector or surrounding materials. Particle identification, beyond that provided by the particle range and dE/dx information, is also available from the relative amount of ionization and excitation losses and is essential for the WIMP searches. The contiguous gas or liquid volume at the heart of a TPC is continuously purified to remove contaminants that would otherwise deteriorate the detector performance or produce backgrounds. The fiducial volume for the event searches can be defined after the fact and is typically chosen to be well separated from the physical boundaries of the working gas or liquid to avoid surface events that often are problematic and much harder to reject in solid state detectors. The scalability of the TPC is one of its most important advantages in a field where ever increasing detector masses are required to achieve the required sensitivities. Detectors of O(100) kg scale are in operation and construction and ton to multi-ton detectors are being planned and expected to come on-line in the next years. In this talk I will describe the various types of TPCs in use or planned and will discuss their potential for achieving the exciting goals of discovering the dark matter particle and observing neutrino-less double beta decays.

  18. Search for Neutrinoless Double-Beta Decay of with CUORE-0

    SciTech Connect

    Alfonso, K.; Artusa, D.  R.; F. T. Avignone; Azzolini, O.; Balata, M.; Banks, T.  I.; Bari, G.; Beeman, J.  W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Caminata, A.; Canonica, L.; Cao, X.  G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R.  J.; Cushman, J.  S.; Dafinei, I.; Dally, A.; Dell’Oro, S.; Deninno, M.  M.; Di Domizio, S.; Di Vacri, M.  L.; Drobizhev, A.; Ejzak, L.; Fang, D.  Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Freedman, S.  J.; Fujikawa, B.  K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T.  D.; Haller, E.  E.; Han, K.; Hansen, E.; Heeger, K.  M.; Hennings-Yeomans, R.; Hickerson, K.  P.; Huang, H.  Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu.  G.; Lim, K.  E.; Liu, X.; Ma, Y.  G.; Maino, M.; Martinez, M.; Maruyama, R.  H.; Mei, Y.; Moggi, N.; Morganti, S.; Nisi, S.; C. Nones; Norman, E.  B.; Nucciotti, A.; O’Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J.  L.; Pagliarone, C.  E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N.  D.; Sisti, M.; Smith, A.  R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S.  L.; Wang, B.  S.; Wang, H.  W.; Wielgus, L.; Wilson, J.; Winslow, L.  A.; Wise, T.; Zanotti, L.; Zarra, C.; Zhang, G.  Q.; Zhu, B.  X.; Zucchelli, S.

    2015-09-03

    We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5.1 ± 0.3 keV FWHM and 0.058 ± 0.004 (stat.) ± 0:002 (syst.) counts/(keV kg yr), respectively. The median 90% C.L. lower-limit sensitivity of the experiment is 2.9 x 1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T0$_1$1/2 > 2.7 x 1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T0$_1$1/2 > 4.0 x 1024 yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, mββ < 270 - 760 meV.

  19. Search for Neutrinoless Double-Beta Decay of Te130 with CUORE-0

    SciTech Connect

    Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Dell’Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O’Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.

    2015-09-03

    We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5:1± 0:3 keV FWHM and 0:058 ± 0:004 (stat) ± 0:002 (syst) counts / (keV kg yr), respectively. The median 90% C.L. lower-limit half-life sensitivity of the experiment is 2:9x1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T1/2 > 2.7 x 1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T1/2 > 4.0 x 1024 yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Lastly, using a range of nuclear matrix element estimates we interpret this as a limit on the e ective Majorana neutrino mass, mββ < 270 -760 meV.

  20. First direct double-beta decay Q-value measurement of the neutrinoless double-beta decay candidate selenium-82 and development of a high-precision magnetometer

    NASA Astrophysics Data System (ADS)

    Lincoln, David Louis

    The results of recent neutrino oscillation experiments indicate that the mass of the neutrino is nonzero. The mass hierarchy and the absolute mass scale of the neutrino, however, are unknown. Furthermore, the nature of the neutrino is also unknown; is it a Dirac or Majorana particle, i.e. is the neutrino its own antiparticle? If experiments succeed in observing neutrinoless double-beta decay, there would be evidence that the neutrino is a Majorana particle and that conservation of total lepton number is violated - a situation forbidden by the Standard Model of particle physics. In support of understanding the nature of the neutrino, the first direct double-beta decay Q-value measurement of the neutrinoless double-beta decay candidate 82Se was performed [D. L. Lincoln et al., Physical Review Letters 110, 012501 (2013)]. The measurement was carried out using Penning trap mass spectrometry, which has proven to be the most precise and accurate method for determining atomic masses and therefore, Q-values. The high-precision measurement resulted in a Q-value with nearly an order of magnitude improvement in precision over the literature value. This result is important for the theoretical interpretations of the observations of current and future double-beta decay studies. It is also important for the design of future and next-generation double-beta decay experiments, such as SuperNEMO, which is planned to observe 100 - 200 kg of 82Se for five years. The high-precision measurement was performed at the Low-Energy Beam and Ion Trap (LEBIT) facility located at the National Superconducting Cyclotron Laboratory (NSCL). The LEBIT facility was the first Penning trap mass spectrometry facility to utilize rare isotope beams produced via fast fragmentation and has measured nearly 40 rare isotopes since its commissioning in 2005. To further improve the LEBIT facility's performance, technical improvements to the system are being implemented. As part of this work, to increase the

  1. A combined limit on the neutrino mass from neutrinoless double-beta decay searches in multiple isotopes

    NASA Astrophysics Data System (ADS)

    Guzowski, P.

    2016-05-01

    We set a combined limit on the effective Majorana neutrino mass mββ from experimental searches for neutrinoless double-beta decay of multiple isotopes. The limits on mββ range between 130-310 meV, depending on the choice of nuclear matrix element calculation. The limits on mββ can also be translated into a limit on the neutrino mass and mixing parameters of a fourth sterile neutrino.

  2. Neutrinoless double {beta}-decay nuclear matrix elements within the SRQRPA with self-consistent short range correlations

    SciTech Connect

    Benes, Petr; Simkovic, Fedor

    2009-11-09

    The nuclear matrix elements M{sup 0v} of the neutrinoless double beta decay (0v{beta}{beta}-decay) are systematically evaluated using the self-consistent renormalized quasiparticle random phase approximation (SRQRPA). The residual interaction and the two-nucleon short-range correlations are derived from the charge-dependent Bonn (CD-Bonn) potential. The importance of further progress in the calculation of the 0v{beta}{beta}-decay nuclear matrix elements is stressed.

  3. Optimization Studies for the COBRA Neutrinoless Double-Beta Decay Experiment and Results from a Prototype

    NASA Astrophysics Data System (ADS)

    Martin, Jerrad Wayne

    The COBRA experiment uses Cadmium Zinc Telluride (CZT) room-temperature semiconductor detectors to search for the neutrinoless double-beta decay of cadmium-116. While the experiment has produced globally competitive half-life limits with data from coplanar-grid CZT detectors, a future ton-scale iteration could set limits constraining the effective Majorana neutrino mass to less than 100 meV. The aim of this work is to determine the optimal CZT detector type for such an experiment. First, an overview of the relevant neutrino physics as well as an introduction to the COBRA experiment is presented. The performance characteristics and design criteria for CZT detectors are then covered, both in general and as they relate to COBRA. Simulations and prototype experiments have been performed using two of the detector design candidates. The method and results are discussed in detail. Finally, the prototype is compared with other CZT detector designs in the context of performance and scalability for a 420 kg COBRA experiment.

  4. Minimally allowed neutrinoless double beta decay rates within an anarchical framework

    NASA Astrophysics Data System (ADS)

    Jenkins, James

    2009-06-01

    Neutrinoless double beta decay (ββ0ν) is the only realistic probe of the Majorana nature of the neutrino. In the standard picture, its rate is proportional to mee, the e-e element of the Majorana neutrino mass matrix in the flavor basis. I explore minimally allowed mee values within the framework of mass matrix anarchy where neutrino parameters are defined statistically at low energies. Distributions of mixing angles are well defined by the Haar integration measure, but masses are dependent on arbitrary weighting functions and boundary conditions. I survey the integration measure parameter space and find that for sufficiently convergent weightings, mee is constrained between (0.01-0.4) eV at 90% confidence. Constraints from neutrino mixing data lower these bounds. Singular integration measures allow for arbitrarily small mee values with the remaining elements ill-defined, but this condition constrains the flavor structure of the model’s ultraviolet completion. ββ0ν bounds below mee˜5×10-3eV should indicate symmetry in the lepton sector, new light degrees of freedom, or the Dirac nature of the neutrino.

  5. Minimally allowed neutrinoless double beta decay rates within an anarchical framework

    SciTech Connect

    Jenkins, James

    2009-06-01

    Neutrinoless double beta decay ({beta}{beta}0{nu}) is the only realistic probe of the Majorana nature of the neutrino. In the standard picture, its rate is proportional to m{sub ee}, the e-e element of the Majorana neutrino mass matrix in the flavor basis. I explore minimally allowed m{sub ee} values within the framework of mass matrix anarchy where neutrino parameters are defined statistically at low energies. Distributions of mixing angles are well defined by the Haar integration measure, but masses are dependent on arbitrary weighting functions and boundary conditions. I survey the integration measure parameter space and find that for sufficiently convergent weightings, m{sub ee} is constrained between (0.01-0.4) eV at 90% confidence. Constraints from neutrino mixing data lower these bounds. Singular integration measures allow for arbitrarily small m{sub ee} values with the remaining elements ill-defined, but this condition constrains the flavor structure of the model's ultraviolet completion. {beta}{beta}0{nu} bounds below m{sub ee}{approx}5x10{sup -3} eV should indicate symmetry in the lepton sector, new light degrees of freedom, or the Dirac nature of the neutrino.

  6. The Search For Neutrinoless Double Beta Decay With The Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Ronquest, Michael

    2012-10-01

    The neutrino sector is currently among the most dynamic topics of particle physics. The past two decades have revealed non-zero neutrino masses, large mixing of mass eigenstates compared to the quark sector and ``large'' values of θ13, with the latter permitting observation of possible CP violation in the neutrino sector. If current theoretical prejudges are confirmed by the identification of neutrinos as Majorana fermions, and thus are their own anti-particles, neutrino CP violation also permits leptogenesis and would thus advance our understanding of the generation mechanism of the matter/anti-matter asymmetry in the current universe. This talk will briefly outline the physics and signatures of neutrinoless double beta decay, which would serve as proof of the Majorana nature of the neutrino. The global program of searches for this process will be reviewed, with emphasis given to the MAJORANA DEMONSTRATOR, an experiment featuring arrays of enriched HPGe detectors serving as both source and detector. The DEMONSTRATOR's design, rich physics reach, and schedule will be detailed. Finally, plans for a ton-scale HPGe experiment to be jointly developed by the MAJORANA and GERDA collaborations will be introduced.

  7. CANDLES - Search for Neutrino-less Double Beta Decay of 48Ca

    NASA Astrophysics Data System (ADS)

    Umehara, Saori; Candles Collaboration

    2014-09-01

    CANDLES is the project to search for neutrino-less double beta decay (0 νββ) of 48Ca. The CANDLES system aims at a high sensitive measurement by a characteristic detector system and 48Ca enrichment. The system realizes a complete 4 π active shield by immersing the CaF2 scintillators in liquid scintillator. The active shield by the liquid scintillator will effectively reject background events from external origins. On the other band, we have studied 48Ca enrichment and succeeded in obtaining enriched 48Ca although it is a small amount. Now we have developed the CANDLES III system, which contained 350 g of 48Ca without enrichment, at the Kamioka underground laboratory. Two improvements, a light-concentration system and a new DAQ system, were installed for the CANDLES III system. The light-concentration system improved a energy resolution by increasing a PMT photo-coverage by 80%. The new DAQ system, which is a dead time less system, improved a rejection efficiency for a characteristic background origin. We checked detector performance with the light-concentration system and the new DAQ system. Here we will report the detector performance for background rejection and the expected sensitivity with the two improvements.

  8. Neutron capture cross-section studies of Tellurium isotopes for neutrinoless double beta decay applications

    NASA Astrophysics Data System (ADS)

    Bhike, Megha; Tornow, Werner

    2014-09-01

    The CUORE detector at Gran Sasso, aimed at searching for neutrinoless double-beta decay of 130Te, employs an array of TeO2 bolometer modules. To understand and identify the contribution of muon and (α,n) induced neutrons to the CUORE background, fast neutron cature cross-section data of the tellurium isotopes 126Te, 128Te and 130Te have been measured with the activation method at eight different energies in the neutron energy range 0.5-7.5 MeV. Plastic pill boxes of diameter 1.6 cm and width 1 cm containing Te were irradiated with mono-energetic neutrons produced via the 3H(p,n)3He and 2H(d,n)3He reactions. The cross-sections were determined relative to the 197Au(n, γ)198Au and 115In(n,n')115m In standard cross sections. The activities of the products were measured using 60% lead-shielded HPGe detectors at TUNL's low background counting facility. The present results are compared with the evaluated data from TENDL-2012, ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0, as well as with literature data.

  9. Cosmogenic Backgrounds to Neutrinoless Double-Beta Decay in EXO-200

    NASA Astrophysics Data System (ADS)

    Albert, Joshua; EXO-200 Collaboration

    2016-03-01

    As neutrinoless double-beta decay (0 νββ) experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood and eliminated. With this in mind, cosmogenic backgrounds have been studied with the EXO-200 experiment. Simulations of muon-induced backgrounds in EXO-200 using Geant4 and FLUKA identified several potential cosmogenic radionuclides, though only 137Xe provides a significant background for the 136Xe 0 νββ search with EXO-200. The simulations were normalized based on a measurement of the muon flux underground using the EXO-200 TPC. Muon-induced neutron backgrounds were measured using γ-rays from neutron capture on the detector materials, in data coincident with veto triggers. This provided a measurement of 137Xe yield, and a test of the accuracy of the neutron production and transport simulations. Simulations agree with data to within ~40 % . The ability to identify 136 Xe (n , γ) events will allow for rejection of 137Xe backgrounds in future 0 νββ analyses.

  10. GraXe, graphene and xenon for neutrinoless double beta decay searches

    NASA Astrophysics Data System (ADS)

    Gómez-Cadenas, J. J.; Guinea, F.; Fogler, M. M.; Katsnelson, M. I.; Martín-Albo, J.; Monrabal, F.; Muñoz Vidal, J.

    2012-02-01

    We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in 136XE. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. In our baseline design of GraXe, a sphere made of graphene-coated titanium mesh and filled with liquid xenon (LXe) enriched in the 136XE isotope is immersed in a large volume of natural LXe instrumented with photodetectors. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, and impermeable to the xenon. Event position could be deduced from the light pattern detected in the photosensors. External backgrounds would be shielded by the buffer of natural LXe, leaving the ultra-radiopure internal volume virtually free of background. Industrial graphene can be manufactured at a competitive cost to produce the sphere. Enriching xenon in the isotope 136XE is easy and relatively cheap, and there is already near one ton of enriched xenon available in the world (currently being used by the EXO, KamLAND-Zen and NEXT experiments). All the cryogenic know-how is readily available from the numerous experiments using liquid xenon. An experiment using the GraXe concept appears realistic and affordable in a short time scale, and its physics potential is enormous.

  11. ZICOS - New project for neutrinoless double beta decay experiment using zirconium complex in liquid scintillator

    NASA Astrophysics Data System (ADS)

    Fukuda, Yoshiyuki

    2016-05-01

    A liquid scintillator containing a tetrakis (isopropyl acetoacetato) zirconium has been developed for new project of neutrinoless double beta decay experiment (ZICOS experiment). We have synthesized a tetrakis (isopropyl acetoacetato) zirconium, which have high solubility (over 31.2 wt.%) in anisole. We measured the performance of liquid scintillator containing 10 wt.% concentration of a tetrakis (isopropyl acetoacetato) zirconium, and obtained 48.7 ± 7.1% of the light yield of BC505 and the energy resolution of 4.1 ± 0.6% at 3.35 MeV assuming 40% photo coverage of the photomultiplier, respectively. We also estimated that ZICOS experiment should be sensitive to (mν) < 0.1 eV assuming gA = 1.25, gpp = 1.11 and QRPA model, if a radius of the inner detector is 1.5 m and the detector is filled with this liquid scintillator with an enriched 96Zr nucleus and we can reduce 208 Tl backgrounds to be one tenth order of magnitude of KamLAND-Zen using Cherenkov lights.

  12. Majorana neutrino masses from neutrinoless double-beta decays and lepton-number-violating meson decays

    NASA Astrophysics Data System (ADS)

    Liu, Jun-Hao; Zhang, Jue; Zhou, Shun

    2016-09-01

    The Schechter-Valle theorem states that a positive observation of neutrinoless double-beta (0 νββ) decays implies a finite Majorana mass term for neutrinos when any unlikely fine-tuning or cancellation is absent. In this note, we reexamine the quantitative impact of the Schechter-Valle theorem, and find that current experimental lower limits on the half-lives of 0 νββ-decaying nuclei have placed a restrictive upper bound on the Majorana neutrino mass | δ mνee | < 7.43 ×10-29 eV radiatively generated at the four-loop level. Furthermore, we generalize this quantitative analysis of 0 νββ decays to that of the lepton-number-violating (LNV) meson decays M- →M‧+ + ℓα- + ℓβ- (for α , β = e or μ). Given the present upper limits on these rare LNV decays, we have derived the loop-induced Majorana neutrino masses | δ mνee | < 9.7 ×10-18 eV, | δ mνeμ | < 1.6 ×10-15 eV and | δ mνμμ | < 1.0 ×10-12 eV from K- →π+ +e- +e-, K- →π+ +e- +μ- and K- →π+ +μ- +μ-, respectively. A partial list of radiative neutrino masses from the LNV decays of D, Ds and B mesons is also given.

  13. LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Vignati, M.

    2012-08-01

    The nature of neutrino mass is one of the frontier problems of particle physics. Neutrinoless Double Beta Decay (0νDBD) is a powerful tool to measure the neutrino mass and to test possible extensions of the Standard Model. Bolometers are excellent detectors to search for this rare decay, thanks to their good energy resolution and to the low background conditions in which they can operate. The current challenge consists in the reduction of the background, represented by environmental γ's and α's, in view of a zero background experiment. We present the LUCIFER R&D, funded by an European grant, in which the background can be reduced by an order of magnitude with respect to the present generation experiments. The technique is based on the simultaneous bolometric measurement of the heat and of the scintillation light produced by a particle, that allows to discriminate between β and α particles. The γ background is reduced by choosing 0νDBD candidate isotopes with transition energy above the environmental γ's spectrum. The prospect of this R&D are discussed.

  14. GraXe, graphene and xenon for neutrinoless double beta decay searches

    SciTech Connect

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Monrabal, F.; Vidal, J. Muñoz; Guinea, F.; Fogler, M.M.; Katsnelson, M.I. E-mail: paco.guinea@icmm.csic.es E-mail: katsnel@sci.kun.nl E-mail: francesc.monrabal@ific.uv.es

    2012-02-01

    We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in {sup 136}XE. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. In our baseline design of GraXe, a sphere made of graphene-coated titanium mesh and filled with liquid xenon (LXe) enriched in the {sup 136}XE isotope is immersed in a large volume of natural LXe instrumented with photodetectors. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, and impermeable to the xenon. Event position could be deduced from the light pattern detected in the photosensors. External backgrounds would be shielded by the buffer of natural LXe, leaving the ultra-radiopure internal volume virtually free of background. Industrial graphene can be manufactured at a competitive cost to produce the sphere. Enriching xenon in the isotope {sup 136}XE is easy and relatively cheap, and there is already near one ton of enriched xenon available in the world (currently being used by the EXO, KamLAND-Zen and NEXT experiments). All the cryogenic know-how is readily available from the numerous experiments using liquid xenon. An experiment using the GraXe concept appears realistic and affordable in a short time scale, and its physics potential is enormous.

  15. Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

    SciTech Connect

    Artusa, D. R.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; Biasi, A. De; Deninno, M. M.; Domizio, S. Di; Vacri, M. L. di; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.

    2014-10-15

    Neutrinoless double beta decay (0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric0νββ experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (|mee|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. In conclusion, we highlight the main challenges and identify priorities for an R&D program addressing them.

  16. Characterization of a ZnSe scintillating bolometer prototype for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Tenconi, M.; Giuliani, A.; Nones, C.; Pessina, G.; Plantevin, O.; Rusconi, C.

    2014-01-01

    As proposed in the LUCIFER project, ZnSe crystals are attractive materials to realize scintillating bolometers aiming at the search for neutrinoless double beta decay of the promising isotope 82Se. However, the optimization of the ZnSe-based detectors is rather complex and requires a wide-range investigation of the crystal features: optical properties, crystalline quality, scintillation yields and bolometric behaviour. Samples tested up to now show problems in the reproducibility of crucial aspects of the detector performance. In this work, we present the results obtained with a scintillating bolometer operated aboveground at about 25 mK. The detector energy absorber was a single 1 cm3 ZnSe crystal. The good energy resolution of the heat channel (about 14 keV at 1460 keV) and the excellent alpha/beta discrimination capability are very encouraging for a successful realization of the LUCIFER program. The bolometric measurements were completed by optical tests on the crystal (optical transmission and luminescence measurements down to 10 K) and investigation of the crystalline structure. The work here described provides a set of parameters and procedures useful for a complete pre-characterization of ZnSe crystals in view of the realization of highly performing scintillating bolometers.

  17. Searching for neutrinoless double-beta decay of {sup 130}Te with CUORE

    SciTech Connect

    CUORE; Artusa, D. R.; Avignone III, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; Biasi, A. De; Deninno, M. M.; Domizio, S. Di; Vacri, M. L. di; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    2014-02-24

    Neutrinoless double-beta (0#23;{nu}{beta}{beta}#12;#12;) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0#23;{nu}{beta}{beta}#23;#12;#12; decay of {sup 130}Te using an array of 988 TeO{sub 2} crystal bolometers operated at 10 mK. The detector will contain 206 kg of {sup 130}Te and have an average energy resolution of 5 keV; the projected 0#23;#23;{nu}{beta}{beta}#12;#12; decay half-life sensitivity after five years of live time is 1.6 #2;x 10{sup 26} y at 1{sigma}#27; (9.5x#2;10{sup 25} y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). In this paper we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

  18. The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

    NASA Astrophysics Data System (ADS)

    Dell'Oro, S.; Marcocci, S.; Viel, M.; Vissani, F.

    2015-12-01

    Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses Σ, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. [JCAP 02 (2015) 045] to the neutrinoless double beta decay (0ν β β) search. This analysis indicates small values for the lightest neutrino mass, since the authors find Σ < 84 meV at 1σ C.L., and provides a 1σ preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0ν β β, turn out to be < 75 meV at 3σ C.L. and lower down to less than 02 meV at 1σ C.L. . If this indication is confirmed, the impact on the 0ν β β experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments.

  19. The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

    SciTech Connect

    Dell’Oro, S.; Marcocci, S.; Viel, M.; Vissani, F.

    2015-12-11

    Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses Σ, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. to the neutrinoless double beta decay (0νββ) search. This analysis indicates small values for the lightest neutrino mass, since the authors find Σ<84 meV at 1σ C.L., and provides a 1σ preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0νββ, turn out to be <75 meV at 3σ C.L. and lower down to less than 20 meV at 1σ C.L. . If this indication is confirmed, the impact on the 0νββ experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments.

  20. Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

    DOE PAGESBeta

    Artusa, D. R.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; et al

    2014-10-15

    Neutrinoless double beta decay (0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric0νββ experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capablemore » of reaching the sensitivity to the effective Majorana neutrino mass (|mee|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. In conclusion, we highlight the main challenges and identify priorities for an R&D program addressing them.« less

  1. Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

    NASA Astrophysics Data System (ADS)

    Sahu, R.; Kota, V. K. B.

    2015-03-01

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70Zn, 80Se and 82Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree-Fock (HF) states. For 70Zn, jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56Ni as the core is employed. However, for 80Se and 82Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70Zn. The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70Zn, 80Se and 82Se, respectively.

  2. Neutrinoless double beta decay. Annual progress report, January 1, 1984-December 31, 1984

    SciTech Connect

    Nicholson, H.W.

    1984-08-01

    Work is continuing on a collaborative experiment with experimenters from the Lawrence Berkeley Laboratory to search for neutrinoless double beta decay in Mo/sup 100/. We have developed a hybrid, lithium drifted, silicon surface barrier detector 1.5 mm thick and 7.1 cm in diameter which, operating at LN/sub 2/ temperature and in conjunction with an Amptek A225 low noise preamplifier and amplifier chip, gives an electronic resolution of 18 keV FWHM. At present, we have 8 working detectors of this type and another 8 currently being fabricated, and we expect to have between 50 and 70 of these detectors working by January 1985. We have also fabricated 5 grams of isotopically pure Mo/sup 100/ into 7 micron thick circular foils 7.1 cm in diameter and have constructed a titanium cryostat with an oxygen-free, high conductivity electrolytic (OFHC) copper dipstick which currently contains a stack of 6 detectors and is being used to evaluate backgrounds from the residual natural radioactivity remaining in the detector system. We hope to begin taking data with 5 to 10% of the full array by early 1985.

  3. Theoretical uncertainties in the nuclear matrix elements of neutrinoless double beta decay: The transition operator

    SciTech Connect

    Menéndez, Javier

    2013-12-30

    We explore the theoretical uncertainties related to the transition operator of neutrinoless double-beta (0νββ) decay. The transition operator used in standard calculations is a product of one-body currents, that can be obtained phenomenologically as in Tomoda [1] or Šimkovic et al. [2]. However, corrections to the operator are hard to obtain in the phenomenological approach. Instead, we calculate the 0νββ decay operator in the framework of chiral effective theory (EFT), which gives a systematic order-by-order expansion of the transition currents. At leading orders in chiral EFT we reproduce the standard one-body currents of Refs. [1] and [2]. Corrections appear as two-body (2b) currents predicted by chiral EFT. We compute the effects of the leading 2b currents to the nuclear matrix elements of 0νββ decay for several transition candidates. The 2b current contributions are related to the quenching of Gamow-Teller transitions found in nuclear structure calculations.

  4. The Gerda experiment for the search of 0 νββ decay in 76Ge

    NASA Astrophysics Data System (ADS)

    Ackermann, K.-H.; Agostini, M.; Allardt, M.; Altmann, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Chkvorets, O.; Cossavella, F.; D`Andragora, A.; Demidova, E. V.; Denisov, A.; di Vacri, A.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Froborg, F.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gasparro, J.; Gazzana, S.; Gonzalez de Orduna, R.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kankanyan, R.; Kianovsky, S.; Kihm, T.; Kiko, J.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knapp, M.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kröninger, K.; Kusminov, V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Lenz, D.; Liao, H.; Lindner, M.; Lippi, I.; Liu, J.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Marissens, G.; Mayer, S.; Meierhofer, G.; Nemchenok, I.; Niedermeier, L.; Nisi, S.; Oehm, J.; O'Shaughnessy, C.; Pandola, L.; Peiffer, P.; Pelczar, K.; Pullia, A.; Riboldi, S.; Ritter, F.; Rossi Alvarez, C.; Sada, C.; Salathe, M.; Schmitt, C.; Schönert, S.; Schreiner, J.; Schubert, J.; Schulz, O.; Schwan, U.; Schwingenheuer, B.; Seitz, H.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stelzer, F.; Strecker, H.; Tarka, M.; Trunk, U.; Ur, C. A.; Vasenko, A. A.; Vogt, S.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2013-03-01

    The Gerda collaboration is performing a search for neutrinoless double beta decay of 76Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase.

  5. Inelastic neutron scattering studies of 76Ge and 76Se: relevance to elevance to neutrinoless double-β decay

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Peters, E. E.; Ross, T. J.; McEllistrem, M. T.; Prados-Estévez, F. M.; Allmond, J. M.; Vanhoy, J. R.; Yates, S. W.

    2015-05-01

    Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched 76Ge and 76Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the 76Ge(n,n'γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β decay of 76Ge. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV γ ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of ~0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported γ rays from levels in 76Ge can be found in the 2039-keV region.

  6. Purifications of calcium carbonate and molybdenum oxide powders for neutrinoless double beta decay experiment, AMoRE

    SciTech Connect

    Park, HyangKyu

    2015-08-17

    The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of {sup 100}Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders.

  7. CANDLES project for the study of neutrino-less double beta decay of 48Ca

    NASA Astrophysics Data System (ADS)

    Yoshida, Sei

    2014-09-01

    There is, presently, strong evidence that neutrinos undergo flavor oscillations,and hence must have finite masses. Neutrino-less double beta (0 νββ) decay measurement offers a realistic opportunity to establish the Majorana nature of neutrinos and gives the absolute scale of the effective neutrino mass. CANDLES is the project to search for 0 νββ decay of 48Ca. A distinctive characteristic of 48Ca is the highest Q value (4.3 MeV) among 0 νββ isotopes. Therefore it enables us to measure 0 νββ decay signals in background free contribution. The CANDLES system consists of undoped CaF2 scintillators (CaF2),liquid scintillator (LS), and large photomultiplier tubes (PMTs). A large number of CaF2 crystals in the form of 10 cm cubes are immersed in the LS. Scintillating CaF2 crystals work as an active source detector for 0 νββ decay of 48Ca, together with LS as a multi-purpose detector component to both reject backgrounds and to propagate scintillation photons. PMTs are placed around the LS vessel to detect photons from both scintillators. The simple design concept of CANDLES enables us to increase the 48Ca source amount. 48Ca enrichment is also effective for the high sensitive measurement, because natural abundance of 48Ca is very low (0.19%). We have studied 48Ca enrichment and succeeded in obtaining enriched 48Ca although it is a small amount. Now we have developed the CANDLES III system, which contained with 300kg CaF2 crystals without enrichment, at the Kamioka underground laboratory. New light collection system was installed in 2012, and accordingly photo-coverage has been enlarged by about 80%. Further improvement will be expected in 2014 by installing a detector cooling system in order to increase light emission from CaF2 crystals. The detail of the latest CANDLES III (U.G.) system and its performance will be presented. Recently, we found that gamma rays from neutron captures on materials surrounding detector could be dominant background. These

  8. Status of double beta decay experiments using isotopes other than 136Xe

    NASA Astrophysics Data System (ADS)

    Pandola, L.

    2014-09-01

    Neutrinoless double beta decay is a lepton-number violating process predicted by many extensions of the standard model. It is actively searched for in several candidate isotopes within many experimental projects. The status of the experimental initiatives which are looking for the neutrinoless double beta decay in isotopes other than 136Xe is reviewed, with special emphasis given to the projects that passed the R&D phase. The results recently released by the experiment GERDA are also summarized and discussed. The GERDA data give no positive indication of neutrinoless double beta decay of 76Ge and disfavor in a model-independent way the long-standing observation claim on the same isotope. The lower limit reported by GERDA for the half-life of neutrinoless double beta decay of 76Ge is T1/20ν > 2.1 ṡ1025 yr (90% C.L.), or T1/20ν > 3.0 ṡ1025 yr, when combined with the results of other 76Ge predecessor experiments.

  9. Direct link between neutrinoless double beta decay and leptogenesis in a seesaw model with S{sub 4} symmetry

    SciTech Connect

    Ahn, Y. H.; Kang, Sin Kyu; Kim, C. S.; Nguyen, T. Phong

    2010-11-01

    We study how leptogenesis can be implemented in a seesaw model with S{sub 4} flavor symmetry, which leads to the neutrino tribimaximal mixing matrix and degenerate right-handed (RH) neutrino spectrum. Introducing a tiny soft S{sub 4} symmetry breaking term in the RH neutrino mass matrix, we show that the flavored resonant leptogenesis can be successfully realized, which can lower the seesaw scale much so, as to make it possible to probe in colliders. Even though such a tiny soft breaking term is essential for leptogenesis, it does not significantly affect the low-energy observables. We also investigate how the effective light neutrino mass || associated with neutrinoless double beta decay can be predicted along with the neutrino mass hierarchies by imposing experimental data of low-energy observables. We find a direct link between leptogenesis and neutrinoless double beta decay characterized by || through a high energy CP phase {phi}, which is correlated with low-energy Majorana CP phases. It is shown that our predictions of || for some fixed parameters of high energy physics can be constrained by the current observation of baryon asymmetry.

  10. Influence of a keV sterile neutrino on neutrinoless double beta decay: How things changed in recent years

    NASA Astrophysics Data System (ADS)

    Merle, Alexander; Niro, Viviana

    2013-12-01

    Earlier studies of the influence of dark matter keV sterile neutrinos on neutrinoless double beta decay concluded that there is no significant modification of the decay rate. These studies have focused only on a mass of the keV sterile neutrino above 2 and 4 keV, respectively, as motivated by certain production mechanisms. On the other hand, alternative production mechanisms have been proposed, which relax the lower limit for the mass, and new experimental data are available, too. For this reason, an updated study is timely and worthwhile. We focus on the most recent data, i.e., the newest Chandra and XMM-Newton observational bounds on the x-ray line originating from radiative keV sterile neutrino decay, as well as the new measurement of the previously unknown leptonic mixing angle θ13. While the previous works might have been a little short-sighted, the new observational bounds do indeed render any influences of keV sterile neutrinos on neutrinoless double beta decay small. This conclusion even holds in case not all the dark matter is made up of keV sterile neutrinos.

  11. Probing new physics models of neutrinoless double beta decay with SuperNEMO

    NASA Astrophysics Data System (ADS)

    Arnold, R.; Augier, C.; Baker, J.; Barabash, A. S.; Basharina-Freshville, A.; Bongrand, M.; Brudanin, V.; Caffrey, A. J.; Cebrián, S.; Chapon, A.; Chauveau, E.; Dafni, T.; Deppisch, F. F.; Diaz, J.; Durand, D.; Egorov, V.; Evans, J. J.; Flack, R.; Fushima, K.-I.; Irastorza, I. García; Garrido, X.; Gómez, H.; Guillon, B.; Holin, A.; Holy, K.; Horkley, J. J.; Hubert, P.; Hugon, C.; Iguaz, F. J.; Ishihara, N.; Jackson, C. M.; Jullian, S.; Kauer, M.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lamhamdi, T.; Lang, K.; Lutter, G.; Luzón, G.; Mamedov, F.; Marquet, C.; Mauger, F.; Monrabal, F.; Nachab, A.; Nasteva, I.; Nemchenok, I.; Nguyen, C. H.; Nomachi, M.; Nova, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P. P.; Richards, B.; Ricol, J. S.; Riddle, C. L.; Rodríguez, A.; Saakyan, R.; Sarazin, X.; Sedgbeer, J. K.; Serra, L.; Shitov, Y.; Simard, L.; Šimkovic, F.; Söldner-Rembold, S.; Štekl, I.; Sutton, C. S.; Tamagawa, Y.; Thomas, J.; Timkin, V.; Tretyak, V.; Tretyak, V. I.; Umatov, V. I.; Vanyushin, I. A.; Vasiliev, R.; Vasiliev, V.; Vorobel, V.; Waters, D.; Yahlali, N.; Žukauskas, A.

    2010-12-01

    The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double β decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double β decay by measuring the decay half-life and the electron angular and energy distributions.

  12. Explaining a CMS e e j j excess with R -parity violating supersymmetry and implications for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Allanach, Ben; Biswas, Sanjoy; Mondal, Subhadeep; Mitra, Manimala

    2015-01-01

    A recent CMS search for the right-handed gauge boson WR reports an interesting deviation from the Standard Model. The search has been conducted in the e e j j channel and has shown a 2.8 σ excess around me e j j˜2 TeV . In this work, we explain the reported CMS excess with R -parity violating supersymmetry. We consider resonant selectron and sneutrino production, followed by the three body decays of the neutralino and chargino via an R -parity violating coupling. We fit the excess for slepton masses around 2 TeV. The scenario can further be tested in neutrinoless double beta decay (0 ν β β ) experiments. GERDA Phase-II will probe a significant portion of the good-fit parameter space.

  13. Probing flavor models with ^{ {76}}Ge-based experiments on neutrinoless double-β decay

    NASA Astrophysics Data System (ADS)

    Agostini, Matteo; Merle, Alexander; Zuber, Kai

    2016-04-01

    The physics impact of a staged approach for double-β decay experiments based on ^{ {76}}Ge is studied. The scenario considered relies on realistic time schedules envisioned by the Gerda and the Majorana collaborations, which are jointly working towards the realization of a future larger scale ^{ {76}}Ge experiment. Intermediate stages of the experiments are conceived to perform quasi background-free measurements, and different data sets can be reliably combined to maximize the physics outcome. The sensitivity for such a global analysis is presented, with focus on how neutrino flavor models can be probed already with preliminary phases of the experiments. The synergy between theory and experiment yields strong benefits for both sides: the model predictions can be used to sensibly plan the experimental stages, and results from intermediate stages can be used to constrain whole groups of theoretical scenarios. This strategy clearly generates added value to the experimental efforts, while at the same time it allows to achieve valuable physics results as early as possible.

  14. Predictions for neutrinoless double-beta decay in the 3+1 sterile neutrino scenario

    NASA Astrophysics Data System (ADS)

    Giunti, C.; Zavanin, E. M.

    2016-05-01

    In this proceeding we present predictions of the effective Majorana mass |mββ| in neutrinoless double-β decay for the standard 3v mixing case and for the 3+1 neutrino mixing case indicated by the short-baseline anomalies. We have taken into account the uncertainties of the neutrino mixing parameters determined by oscillation experiments. We obtained that the predictions for |mββ| in the cases of 3v and 3+1 mixing are quite different, in agreement with previous discussions in the literature, and that future measurements of neutrinoless double-β decay and the total mass of the three lightest neutrinos in cosmological experiments may distinguish the 3v and 3+1 cases if the mass ordering is determined by oscillation experiments.

  15. Neutron inelastic scattering in natural Pb as a background in neutrinoless double-beta decay experiments

    SciTech Connect

    Guiseppe, Vincente E; Elliott, Steve R; Hime, Andrew; Perepelitsa, Dennis V

    2008-01-01

    Inelastic neutron scattering on Pb isotopes can result in {gamma} rays near the signature endpoint energy in a number of {beta}{beta} isotopes. In particular, there are {gamma}-ray transitions in {sup 206}Pb and {sup 207}Pb that might produce energy deposits at the {sup 76}Ge Q{sub {beta}{beta}} in Ge detectors used for 0{nu}{beta}{beta} searches. The levels that produce these {gamma} rays can be excited by n,n'{gamma} reactions, but the cross sections are small and previously unmeasured. The cross section on {sup nat}Pb to produce the 2041-keV {gamma} ray from {sup 206}Pb is measured to be 3.1 {+-} 0.6 (stat.) {+-} 0.3 (syst.) mb at {approx} 9.6 MeV. The cross section on {sup nat}Pb to produce the 3062-keV {gamma} ray from {sup 207}Pb is measured to be 4.3 {+-} 0.8 (stat.) {+-} 0.4 (syst.) mb at the same energy. We place upper limits on the cross sections for exciting some other levels in Pb that have transition energies corresponding to Q{sub {beta}{beta}} in orhter {beta}{beta} isotopes.

  16. Prompt Gamma Rays in {sup 77}Ge after Neutron Capture on {sup 76}Ge

    SciTech Connect

    Meierhofer, Georg; Grabmayr, Peter; Jochum, Josef; Canella, Lea; Jolie, Jan; Kudejova, Petra; Warr, Nigel

    2009-01-28

    The observation of neutrinoless double beta decay would be proof of the Majorana nature of the neutrino. Half-lives for these decays are very long (for {sup 76}Ge:>10{sup 25} y), so background reduction and rejection is the major task for double beta experiments. The GERDA (GERmanium Detector Array) experiment at the Gran Sasso Laboratory of the INFN (LNGS) searches for neutrinoless double beta decay of {sup 76}Ge. The isotope {sup 76}Ge is an ideal candidate because it can be used as source and detector at the same time. A large remaining contribution to the background arises from the prompt gamma cascade after neutron capture by {sup 76}Ge followed by {beta}{sup -}-decay of {sup 77}Ge. Since the prompt gamma decay scheme is poorly known, measurements with isotopically enriched Germanium samples were carried out at the PGAA facility at the research reactor FRM II (Munich). With the known prompt gamma spectrum it will be possible to improve the overall veto efficiency of the GERDA experiment.

  17. Neganov-Luke amplified cryogenic light detectors for the background discrimination in neutrinoless double beta decay search with TeO2 bolometers

    NASA Astrophysics Data System (ADS)

    Willers, M.; Feilitzsch, F. v.; Gütlein, A.; Münster, A.; Lanfranchi, J.-C.; Oberauer, L.; Potzel, W.; Roth, S.; Schönert, S.; Sivers, M. v.; Wawoczny, S.; Zöller, A.; Giuliani, A.

    2015-03-01

    We demonstrate that Neganov-Luke amplified cryogenic light detectors with Transition Edge Sensor read-out can be applied for the background suppression in cryogenic experiments searching for the neutrinoless double beta decay of 130Te with TeO2 based bolometers. Electron and gamma induced events can be discriminated from α events by detecting the Cherenkov light produced by the β particles emitted in the decay. We use the Cherenkov light produced by events in the full energy peak of 208Tl and by events from a 147Sm source to show that at the Q-value of the neutrinoless double beta decay of 130Te (Qβ β = 2.53 MeV), a separation of e-/γ events from α events can be achieved on an event-by-event basis with practically no reduction in signal acceptance.

  18. Searching for Neutrinoless Double-Beta Decay of 130 Te with CUORE

    DOE PAGESBeta

    Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; et al

    2015-01-01

    Neumore » trinoless double-beta (0 ν β β ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0 ν β β decay of 130 Te using an array of 988 TeO 2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130 Te and have an average energy resolution of 5 keV; the projected 0 ν β β decay half-life sensitivity after five years of livetime is 1.6 × 10 26  y at 1 σ (9.5 × 10 25  y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.« less

  19. Secondary scintillation yield in high-pressure xenon gas for neutrinoless double beta decay (0νββ) search

    NASA Astrophysics Data System (ADS)

    Freitas, E. D. C.; Monteiro, C. M. B.; Ball, M.; Gómez-Cadenas, J. J.; Lopes, J. A. M.; Lux, T.; Sánchez, F.; dos Santos, J. M. F.

    2010-02-01

    The search for neutrinoless double beta decay (0νββ) is an important topic in contemporary physics with many active experiments. New projects are planning to use high-pressure xenon gas as both source and detection medium. The secondary scintillation processes available in noble gases permit large amplification with negligible statistical fluctuations, offering the prospect of energy resolution approaching the Fano factor limit. This Letter reports results for xenon secondary scintillation yield, at room temperature, as a function of electric field in the gas scintillation gap for pressures ranging from 2 to 10 bar. A Large Area Avalanche Photodiode (LAAPD) collected the VUV secondary scintillation produced in the gas. X-rays directly absorbed in the LAAPD are used as a reference for determining the number of charge carriers produced by the scintillation pulse and, hence, the number of photons impinging the LAAPD. The number of photons produced per drifting electron and per kilovolt, the so-called scintillation amplification parameter, displays a small increase with pressure, ranging from 141±6 at 2 bar to 170±10 at 8 bar. In our setup, this parameter does not increase above 8 bar due to non-negligible electron attachment. The results are in good agreement with those presented in the literature in the 1 to 3 bar range. The increase of the scintillation amplification parameter with pressure for high gas densities has been also observed in former work at cryogenic temperatures.

  20. The scalar triplet contribution to lepton flavour violation and neutrinoless double beta decay in Left-Right Symmetric Model

    NASA Astrophysics Data System (ADS)

    Bambhaniya, Gulab; Dev, P. S. Bhupal; Goswami, Srubabati; Mitra, Manimala

    2016-04-01

    We analyse in detail the scalar triplet contribution to the low-energy lepton flavour violating (LFV) and lepton number violating (LNV) processes within a TeV-scale left-right symmetric framework. We show that in both type-I and type-II seesaw dominance for the light neutrino masses, the triplet of mass comparable to or smaller than the largest right-handed neutrino mass scale can give sizeable contribution to the LFV processes, except in the quasi-degenerate limit of light neutrino masses, where a suppression can occur due to cancellations. In particular, a moderate value of the heaviest neutrino to scalar triplet mass ratio r≲ O(1) is still experimentally allowed and can be explored in the future LFV experiments. Similarly, the contribution of a relatively light triplet to the LNV process of neutrinoless double beta decay could be significant, disfavouring a part of the model parameter space otherwise allowed by LFV constraints. Nevertheless, we find regions of parameter space consistent with both LFV and LNV searches, for which the values of the total effective neutrino mass can be accessible to the next generation ton-scale experiments. Such light triplets can also be directly searched for at the LHC, thus providing a complementary probe of this scenario. Finally, we also study the implications of the triplet contribution for the left-right symmetric model interpretation of the recent diboson anomaly at the LHC.

  1. LUMINEU: a search for neutrinoless double beta decay based on ZnMoO4 scintillating bolometers

    NASA Astrophysics Data System (ADS)

    Armengaud, E.; Arnaud, Q.; Augier, C.; Benoît, A.; Benoît, A.; Boiko, L. Bergé S.; Bergmann, T.; Blümer, J.; Broniatowski, A.; Brudanin, V.; Camus, P.; Cazes, A.; Chapellier, M.; Charlieux, F.; Chernyak, D. M.; Coron, N.; Coulter, P.; Danevich, F. A.; de Boissiére, T.; Decourt, R.; De Jesus, M.; Devoyon, L.; Drillien, A.-A.; Dumoulin, L.; Eitel, K.; Enss, C.; Filosofov, D.; Fleischmann, A.; Foerster, N.; Fourches, N.; Gascon, J.; Gastaldo, L.; Gerbier, G.; Giuliani, A.; Gray, D.; Gros, M.; Hehn, L.; Henry, S.; Hervé, S.; Heuermann, G.; Humbert, V.; Ivanov, I. M.; Juillard, A.; Kéfélian, C.; Kleifges, M.; Kluck, H.; Kobychev, V. V.; Koskas, F.; Kozlov, V.; Kraus, H.; Kudryavtsev, V. A.; Le Sueur, H.; Loidl, M.; Magnier, P.; Makarov, E. P.; Mancuso, M.; de Marcillac, P.; Marnieros, S.; Marrache-Kikuchi, C.; Menshikov, A.; Nasonov, S. G.; Navick, X.-F.; Nones, C.; Olivieri, E.; Pari, P.; Paul, B.; Penichot, Y.; Pessina, G.; Piro, M. C.; Plantevin, O.; Poda, D. V.; Redon, T.; Robinson, M.; Rodrigues, M.; Rozov, S.; Sanglard, V.; Schmidt, B.; Scorza, S.; Shlegel, V. N.; Siebenborn, B.; Strazzer, O.; Tcherniakhovski, D.; Tenconi, M.; Torres, L.; Tretyak, V. I.; Vagneron, L.; Vasiliev, Ya V.; Velazquez, M.; Viraphong, O.; Walker, R. J.; Weber, M.; Yakushev, E.; Zhang, X.; Zhdankov, V. N.

    2016-05-01

    The LUMINEU is designed to investigate the possibility to search for neutrinoless double beta decay in 100 Mo by means of a large array of scintillating bolometers based on ZnMoO4 crystals enriched in 100 Mo. High energy resolution and relatively fast detectors, which are able to measure both the light and the heat generated upon the interaction of a particle in a crystal, are very promising for the recognition and rejection of background events. We present the LUMINEU concepts and the experimental results achieved aboveground and underground with large-mass natural and enriched crystals. The measured energy resolution, the α/β discrimination power and the radioactive internal contamination are all within the specifications for the projected final LUMINEU sensitivity. Simulations and preliminary results confirm that the LUMINEU technology can reach zero background in the region of interest (around 3 MeV) with exposures of the order of hundreds kgxyears, setting the bases for a next generation 0v2β decay experiment capable to explore the inverted hierarchy region of the neutrino mass pattern.

  2. CALDER - Neutrinoless double-beta decay identification in TeO2 bolometers with kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Vignati, M.; Bellini, F.; Cardani, L.; Casali, N.; Castellano, M. G.; Colantoni, I.; Coppolecchia, A.; Cosmelli, C.; Cruciani, A.; D’Addabbo, A.; Di Domizio, S.; Martinez, M.; Tomei, C.

    2016-05-01

    Next-generation experiments searching for neutrinoless double-beta decay must be sensitive to a Majorana neutrino mass as low as 10 meV. CUORE, an array of 988 TeO2 bolometers being commissioned at Laboratori Nazionali del Gran Sasso in Italy, features an expected sensitivity of 50-130 meV at 90% C.L, that can be improved by removing the background from α radioactivity. This is possible if, in coincidence with the heat release in a bolometer, the Cherenkov light emitted by the β signal is detected. The amount of light detected is so far limited to only 100 eV, requiring low-noise cryogenic light detectors. The CALDER project (Cryogenic wide-Area Light Detectors with Excellent Resolution) aims at developing a small prototype experiment consisting of TeO2 bolometers coupled to new light detectors based on kinetic inductance detectors. The present R&D is focused on the light detectors. We present the latest results and the perspectives of the project.

  3. Energy Calibration for a Sensitive Search for Neutrinoless Double-Beta Decay: Using the Cuoricino Experience to Prepare for CUORE

    NASA Astrophysics Data System (ADS)

    Ejzak, Larissa M.

    Neutrinos, which were long believed to be massless particles, are now known to have a tiny finite mass. A thorough understanding of the properties of their masses may provide vital clues to the history of the development of the universe as we know it. An intensive experimental search is underway for evidence of a Majorana mass component to the neutrino via many current and upcoming detectors seeking to observe the rare nuclear process neutrinoless double-beta decay (0nubetabeta). These detectors must be able to achieve very low backgrounds and a precise understanding of their energy scales. This paper presents the experimental approach of one of these 0nubetabeta experiments, the Cryogenic Underground Observatory for Rare Events (CUORE), and the attendant challenges of achieving excellent energy calibration performance in the detector from the perspectives of both hardware design and analysis. Experience and data from Cuoricino, the predecessor of CUORE, have been extensively leveraged to prepare optimized operational procedures for CUORE. The expected sensitivity profile of CUORE as a function of time is also presented and compared with those of other leading 0nubetabeta experiments.

  4. Deformed shell model results for neutrinoless positron double beta decay of nuclei in the A = 60-90 region

    NASA Astrophysics Data System (ADS)

    Sahu, R.; Srivastava, P. C.; Kota, V. K. B.

    2013-09-01

    Nuclear transition matrix elements (NTME) for neutrinoless positron double beta decay (0νβ+β+ and 0νβ+EC) of 64Zn, 74Se, 78Kr and 84Sr nuclei, which are in the A = 60-90 region, are calculated within the framework of the deformed shell model (DSM) based on Hartree-Fock states. For 64Zn, GXPF1A interaction in 1f7/2, 2p3/2, 1f5/2 and 2p1/2 space with 40Ca as the core is employed. Similarly for 74Se, 78Kr and 84Sr nuclei, 56Ni is taken as the inert core employing a modified Kuo interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space. After ensuring that the DSM gives a good description of the spectroscopic properties of low-lying levels in the four nuclei considered, the NTME are calculated. The half-lives deduced with these NTME, assuming the neutrino mass is 1 eV, are smallest for 78Kr with the half-life for β+EC decay being ˜1027 yr. For all others, the half-lives are in the range of ˜1028-1029 yr.

  5. TeV-scale left-right symmetry and large mixing effects in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Bhupal Dev, P. S.; Goswami, Srubabati; Mitra, Manimala

    2015-06-01

    We revisit various contributions to neutrinoless double beta decay (0 ν β β ) in a TeV-scale left-right symmetric model (LRSM) for type-I seesaw dominance. We show that the momentum-dependent effects due to WL-WR exchange (λ diagram) and WL-WR mixing (η diagram) could give dominant contributions to the 0 ν β β amplitude in a wide range of the LRSM parameter space with large left-right neutrino mixing. In particular, for a relatively large WL-WR mixing, the η contribution by itself could saturate the current experimental limit on the 0 ν β β half-life, thereby providing stringent constraints on the relevant LRSM parameters, complementary to the indirect constraints derived from lepton-flavor-violating observables. In a simplified scenario parametrized by a single light-heavy neutrino mixing, the inclusion of the λ and η contributions leads to significantly improved 0 ν β β constraints on the light-heavy neutrino mixing as well as on the WL-WR mixing parameters. We also present a concrete TeV-scale LRSM setup, where the mixing effects are manifestly enhanced, and discuss the interplay between 0 ν β β , lepton flavor violation, and electric dipole moment constraints.

  6. Inelastic neutron scattering studies of Ge-76 and Se-76: relevance to neutrinoless double-beta decay

    SciTech Connect

    Crider, Ben; Peters, Erin; Ross, T.J.; McEllistrem, M; Prados-Estevez, F.; Allmond, James M; Vanhoy, J.R.; Yates, S.W.

    2015-01-01

    Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched Ge-76 and Se-76 scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, gamma-ray cross sections for the Ge-76(n,n'gamma) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of gamma rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double beta decay of Ge-76. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV gamma ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of similar to 0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported gamma rays from levels in Ge-76 can be found in the 2039-keV region.

  7. Search for neutrinoless double-beta decay of Mo100 with the NEMO-3 detector

    NASA Astrophysics Data System (ADS)

    Arnold, R.; Augier, C.; Baker, J. D.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Blot, S.; Bongrand, M.; Brudanin, V.; Busto, J.; Caffrey, A. J.; Cerna, C.; Chapon, A.; Chauveau, E.; Duchesneau, D.; Durand, D.; Egorov, V.; Eurin, G.; Evans, J. J.; Flack, R.; Garrido, X.; Gómez, H.; Guillon, B.; Guzowski, P.; Hodák, R.; Hubert, P.; Hugon, C.; Jullian, S.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lalanne, D.; Lang, K.; Lemière, Y.; Liptak, Z.; Loaiza, P.; Lutter, G.; Mamedov, F.; Marquet, C.; Mauger, F.; Morgan, B.; Mott, J.; Nemchenok, I.; Nomachi, M.; Nova, F.; Nowacki, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P.; Ramachers, Y. A.; Remoto, A.; Reyss, J. L.; Richards, B.; Riddle, C. L.; Rukhadze, E.; Saakyan, R.; Sarazin, X.; Shitov, Yu.; Simard, L.; Šimkovic, F.; Smetana, A.; Smolek, K.; Smolnikov, A.; Söldner-Rembold, S.; Soulé, B.; Štekl, I.; Suhonen, J.; Sutton, C. S.; Szklarz, G.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, Vl. I.; Tretyak, V. I.; Umatov, V. I.; Vanushin, I.; Vilela, C.; Vorobel, V.; Waters, D.; Žukauskas, A.; NEMO-3 Collaboration

    2014-06-01

    We report the results of a search for the neutrinoless double-β decay (0νββ) of Mo100, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg .y, no evidence for the 0νββ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T1/2(0νββ)>1.1×1024 years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of ⟨mν⟩<0.3-0.9 eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0νββ decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2-10] MeV is observed for an exposure of 47 kg .y.

  8. Search for neutrinoless double-beta decay of Mo 100 with the NEMO-3 detector

    SciTech Connect

    John D. Baker; A. J. Caffrey

    2014-06-01

    We report the results of a search for the neutrinoless double-ß decay (0?ßß ) of Mo 100 , using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7??kg·y , no evidence for the 0?ßß signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T 1/2 (0?ßß)>1.1×10 24 years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of ?m ? ?<0.3–0.9??eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0?ßß decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2–10] MeV is observed for an exposure of 47??kg·y .

  9. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    DOE PAGESBeta

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A.B.; Nygren, D.

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at themore » 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.« less

  10. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A. B.; Nygren, D.

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase o_ers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

  11. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    SciTech Connect

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A.B.; Nygren, D.

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

  12. Improved background rejection in neutrinoless double beta decay experiments using a magnetic field in a high pressure xenon TPC

    NASA Astrophysics Data System (ADS)

    Renner, J.; Cervera, A.; Hernando, J. A.; Imzaylov, A.; Monrabal, F.; Muñoz, J.; Nygren, D.; Gomez-Cadenas, J. J.

    2015-12-01

    We demonstrate that the application of an external magnetic field could lead to an improved background rejection in neutrinoless double-beta (0νββ) decay experiments using a high-pressure xenon (HPXe) TPC. HPXe chambers are capable of imaging electron tracks, a feature that enhances the separation between signal events (the two electrons emitted in the 0νββ decay of 136Xe) and background events, arising chiefly from single electrons of kinetic energy compatible with the end-point of the 0νββ decay (0Qββ). Applying an external magnetic field of sufficiently high intensity (in the range of 0.5-1 Tesla for operating pressures in the range of 5-15 atmospheres) causes the electrons to produce helical tracks. Assuming the tracks can be properly reconstructed, the sign of the curvature can be determined at several points along these tracks, and such information can be used to separate signal (0νββ) events containing two electrons producing a track with two different directions of curvature from background (single-electron) events producing a track that should spiral in a single direction. Due to electron multiple scattering, this strategy is not perfectly efficient on an event-by-event basis, but a statistical estimator can be constructed which can be used to reject background events by one order of magnitude at a moderate cost (about 30%) in signal efficiency. Combining this estimator with the excellent energy resolution and topological signature identification characteristic of the HPXe TPC, it is possible to reach a background rate of less than one count per ton-year of exposure. Such a low background rate is an essential feature of the next generation of 0νββ experiments, aiming to fully explore the inverse hierarchy of neutrino masses.

  13. Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

    SciTech Connect

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C. E-mail: jmalbos@ific.uv.es E-mail: penya@ific.uv.es

    2013-03-01

    The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm{sub ν} = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m{sub ββ} involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.

  14. Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches

    NASA Astrophysics Data System (ADS)

    Nakajima, Y.; Goldschmidt, A.; Matis, H. S.; Miller, T.; Nygren, D. R.; Oliveira, C. A. B.; Renner, J.

    2016-03-01

    The gaseous Xenon(Xe) time projection chamber (TPC) is an attractive detector technique for neutrinoless double beta decay and WIMP dark matter searches. While it is less dense compared to Liquid Xe detectors, it has intrinsic advantages in tracking capability and better energy resolution. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which is expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). In order to test the feasibility of the performance improvements with TMA, we made the first direct measurement of Penning and fluorescence transfer efficiency with gaseous mixtures of Xe and TMA. While we observed a Penning transfer efficiency up to ~35%, we found strong suppression of primary scintillation light with TMA. We also found that the primary scintillation light with Xe and TMA mixture can be well characterized by ~3% fluorescence transfer from Xe to TMA, with further suppression due to TMA self-quenching. No evidence of the scintillation light produced by recombination of TMA ions was found. This strong suppression of scintillation light makes dark matter searches quite challenging, while the possibility of improved neutrinoless double beta decay searches remains open. This work has been carried out within the context of the NEXT collaboration.

  15. Elastic and Inelastic Scattering of Neutrons from Neon and Argon: Impact on Neutrinoless Double-Beta Decay and Dark Matter Experimental Programs

    NASA Astrophysics Data System (ADS)

    MacMullin, Sean Patrick

    In underground physics experiments, such as neutrinoless double-beta decay and dark matter searches, fast neutrons may be the dominant and potentially irreducible source of background. Experimental data for the elastic and inelastic scattering cross sections of neutrons from argon and neon, which are target and shielding materials of interest to the dark matter and neutrinoless double-beta decay communities, were previously unavailable. Unmeasured neutron scattering cross sections are often accounted for incorrectly in Monte-Carlo simulations. Elastic scattering cross sections were measured at the Triangle Universities Nuclear Laboratory (TUNL) using the neutron time-of-flight technique. Angular distributions for neon were measured at 5.0 and 8.0 MeV. One full angular distribution was measured for argon at 6.0 MeV. The cross-section data were compared to calculations using a global optical model. Data were also fit using the spherical optical model. These model fits were used to predict the elastic scattering cross section at unmeasured energies and also provide a benchmark where the global optical models are not well constrained. Partial gamma-ray production cross sections for (n,xngamma ) reactions in natural argon and neon were measured using the broad spectrum neutron beam at the Los Alamos Neutron Science Center (LANSCE). Neutron energies were determined using time of flight and resulting gamma rays from neutron-induced reactions were detected using the GErmanium Array for Neutron Induced Excitations (GEANIE). Partial gamma-ray production cross sections for six transitions in 40Ar, two transitions in 39Ar and the first excited state transitions is 20Ne and 22Ne were measured from threshold to a neutron energy where the gamma-ray yield dropped below the detection sensitivity. Measured (n,xngamma) cross sections were compared with calculations using the TALYS and CoH3 nuclear reaction codes. These new measurements will help to identify potential backgrounds in

  16. Aboveground test of an advanced Li2MoO4 scintillating bolometer to search for neutrinoless double beta decay of 100Mo

    NASA Astrophysics Data System (ADS)

    Bekker, T. B.; Coron, N.; Danevich, F. A.; Degoda, V. Ya.; Giuliani, A.; Grigorieva, V. D.; Ivannikova, N. V.; Mancuso, M.; de Marcillac, P.; Moroz, I. M.; Nones, C.; Olivieri, E.; Pessina, G.; Poda, D. V.; Shlegel, V. N.; Tretyak, V. I.; Velazquez, M.

    2016-01-01

    Large lithium molybdate (Li2MoO4) crystal boules were produced by using the low thermal gradient Czochralski growth technique from deeply purified molybdenum. A small sample from one of the boules was preliminary characterized in terms of X-ray-induced and thermally-excited luminescence. A large cylindrical crystalline element (with a size of ⊘40 × 40 mm) was used to fabricate a scintillating bolometer, which was operated aboveground at ˜15 mK by using a pulse-tube cryostat housing a high-power dilution refrigerator. The excellent detector performance in terms of energy resolution and α background suppression along with preliminary positive indications on the radiopurity of this material show the potentiality of Li2MoO4 scintillating bolometers for low-counting experiment to search for neutrinoless double beta decay of 100Mo.

  17. Nuclear Structure Studies of 76Se and 76Ge with the (n ,n' γ) Reaction

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Chakraborty, A.; Kumar, A.; Peters, E. E.; Prados-Estévez, F. M.; McEllistrem, M. T.; Yates, S. W.

    2011-10-01

    A prominent nucleus which may undergo neutrinoless double beta decay is 76Ge, which decays to 76Se. While an unambiguous observation of this lepton-number-violating decay mode has not been made, much work is in progress to obtain the data required for an accurate calculation of the nuclear matrix element (NME), which is vital to extracting the absolute mass scale of the neutrino. In order to provide more information for calculation of the NME, excitation function and gamma-ray angular distributions were performed at the University of Kentucky utilizing the 76Ge(n ,n' γ) and 76Se(n ,n' γ) reactions. Spectroscopic information such as lifetimes, parities, and new transitions will be presented. This work is supported by the U.S. National Science Foundation under grant no. PHY-0956310.

  18. Neutron inelastic scattering processes as a background for double-{beta} decay experiments

    SciTech Connect

    Mei, D.-M.; Elliott, S. R.; Hime, A.; Gehman, V.; Kazkaz, K.

    2008-05-15

    We investigate several Pb(n,n{sup '}{gamma}) and Ge(n,n{sup '}{gamma}) reactions. We measure {gamma}-ray production from Pb(n,n{sup '}{gamma}) reactions that can be a significant background for double-{beta} decay experiments which use lead as a massive inner shield. Particularly worrisome for Ge-based double-{beta} decay experiments are the 2041-keV and 3062-keV {gamma} rays produced via Pb(n,n{sup '}{gamma}). The former is very close to the {sup 76}Ge double-{beta} decay endpoint energy and the latter has a double escape peak energy near the endpoint. We discuss the implications of these {gamma} rays on past and future double-{beta} decay experiments and estimate the cross section to excite the level that produces the 3062-keV {gamma} ray. Excitation {gamma}-ray lines from Ge(n,n{sup '}{gamma}) reactions are also observed. We consider the contribution of such backgrounds and their impact on the sensitivity of next-generation searches for neutrinoless double-{beta} decay using enriched germanium detectors.

  19. Neutron inelastic scattering and reactions in natural Pb as a background in neutrinoless double-{beta}-decay experiments

    SciTech Connect

    Guiseppe, V. E.; Devlin, M.; Elliott, S. R.; Fotiades, N.; Hime, A.; Nelson, R. O.; Perepelitsa, D. V.; Mei, D.-M.

    2009-05-15

    Inelastic neutron scattering and reactions on Pb isotopes can result in {gamma} rays near the signature end-point energy in a number of {beta}{beta} isotopes. In particular, there are {gamma}-ray transitions in {sup 206,207,208}Pb that might produce energy deposits at the {sup 76}GeQ{sub {beta}}{sub {beta}} in Ge detectors used for 0{nu}{beta}{beta} searches. The levels that produce these {gamma} rays can be excited by (n,n{sup '}{gamma}) or (n,xn{gamma}) reactions, but the cross sections are small and previously unmeasured. This work uses the pulsed neutron beam at the Los Alamos Neutron Science Center to directly measure reactions of interest to {beta}{beta}-decay experiments. The cross section on {sup nat}Pb to produce the 2041-keV {gamma} ray from {sup 206}Pb is measured to be 3.6 {+-} 0.7 (stat.) {+-} 0.3 (syst.) mb at {approx_equal}9.6 MeV. The cross section on {sup nat}Pb to produce the 3061,3062-keV {gamma} rays from {sup 207}Pb and {sup 208}Pb is measured to be 3.9 {+-} 0.8 (stat.) {+-} 0.4 (syst.) mb at the same energy. We report cross sections or place upper limits on the cross sections for exciting some other levels in Pb that have transition energies corresponding to Q{sub {beta}}{sub {beta}} in other {beta}{beta} isotopes.

  20. Superconducting Aluminum Layers as Pulse Shape Modifiers: An Innovative Solution to Fight Against Surface Background in Neutrinoless Double Beta Decay Experiments

    NASA Astrophysics Data System (ADS)

    Nones, C.; Bergé, L.; Dumoulin, L.; Marnieros, S.; Olivieri, E.

    2012-06-01

    The most limiting factor for experiments looking for rare events, such as neutrinoless double beta decay, is the radioactive background. We will describe an innovative technique for the discrimination of the surface background which combine the use of thin layers of superconducting aluminum, deposited on a crystal operated as a macro-bolometer and with a fast thermistor, such as a NbSi thin film acting as out-of-equilibrium phonon sensor. The working principle is based on the fact that particles which transfer energy into the Al film create quasi-particles that release heat to the crystal with a considerable delay, that may be in the millisecond range. It is thus clear that pulses acquired from a fast thermistor in the case of surface and bulk events should have different shapes, depending on the place of the initial energy release. Here we present preliminary results on a small TeO2 crystal equipped with NbSi films and an Al film with a thickness of 10 μm. We prove that we are able to identify alpha surface events by pulse shape analysis with a good separation between bulk and surface events. The possibility to extend this rejection technique to bolometers equipped with slow temperature sensors as neutron transmutation doped Ge thermistors is under study.

  1. Implications of the diboson excess for neutrinoless double beta decay and lepton flavor violation in TeV scale left-right symmetric model

    NASA Astrophysics Data System (ADS)

    Awasthi, Ram Lal; Dev, P. S. Bhupal; Mitra, Manimala

    2016-01-01

    Inspired by the recent diboson excess observed at the LHC and possible interpretation within a TeV-scale left-right symmetric framework, we explore its implications for low-energy experiments searching for lepton number and flavor violation. Assuming a simple type-II seesaw mechanism for neutrino masses, we show that for the right-handed (RH) gauge boson mass and coupling values required to explain the LHC anomalies, the RH contribution to the lepton number violating process of neutrinoless double beta decay (0 ν β β ) is already constrained by current experiments for relatively low-mass (MeV-GeV) RH neutrinos. The future ton-scale 0 ν β β experiments could probe most of the remaining parameter space, irrespective of the neutrino mass hierarchy and uncertainties in the oscillation parameters and nuclear matrix elements. On the other hand, the RH contribution to the lepton flavor violating process of μ →e γ is constrained for relatively heavier (TeV) RH neutrinos, thus providing a complementary probe of the model. Finally, a measurement of the absolute light neutrino mass scale from future precision cosmology could make this scenario completely testable.

  2. The COBRA Double Beta Decay Search Experiment

    NASA Astrophysics Data System (ADS)

    Stewart, D. Y.

    2006-11-01

    The COBRA experiment aims to use a large quantity of CdZnTe semiconductor detectors to search for neutrinoless double beta decay. The current status of the experiment is discussed, and new limits on several double beta modes are presented. Future plans for a large scale experiment are also described.

  3. The COBRA double-beta decay experiment

    NASA Astrophysics Data System (ADS)

    Stewart, D. Y.; COBRA Collaboration

    2007-09-01

    The COBRA experiment aims to use a large quantity of Cadmium-Zinc-Telluride (CdZnTe) semiconductor detectors to search for neutrinoless double-beta decay (0 υββ). The current status of the experiment is discussed, and new limits on several double-beta modes are presented. Future plans for a large-scale experiment are also described.

  4. The COBRA Double Beta Decay Search Experiment

    SciTech Connect

    Stewart, D. Y.

    2006-11-17

    The COBRA experiment aims to use a large quantity of CdZnTe semiconductor detectors to search for neutrinoless double beta decay. The current status of the experiment is discussed, and new limits on several double beta modes are presented. Future plans for a large scale experiment are also described.

  5. Charged lepton flavour violcxmation and neutrinoless double beta decay in left-right symmetric models with type I+II seesaw

    NASA Astrophysics Data System (ADS)

    Borah, Debasish; Dasgupta, Arnab

    2016-07-01

    We study the new physics contributions to neutrinoless double beta decay (0 νββ) half-life and lepton flavour violation (LFV) amplitude within the framework of the minimal left-right symmetric model (MLRSM). Considering all possible new physics contributions to 0 νββ and charged lepton flavour violation μ → eγ , μ → 3 e in MLRSM, we constrain the parameter space of the model from the requirement of satisfying existing experimental bounds. Assuming the breaking scale of the left-right symmetry to be O (1) TeV accessible at ongoing and near future collider experiments, we consider the most general type I+II seesaw mechanism for the origin of tiny neutrino masses. Choosing the relative contribution of the type II seesaw term allows us to calculate the right handed neutrino mass matrix as well as Dirac neutrino mass matrix as a function of the model parameters, required for the calculation of 0νββ and LFV amplitudes. We show that such a general type I+II seesaw structure results in more allowed parameter space compared to individual type I or type II seesaw cases considered in earlier works. In particular, we show that the doubly charged scalar masses M Δ are allowed to be smaller than the heaviest right handed neutrino mass M N from the present experimental bounds in these scenarios which is in contrast to earlier results with individual type I or type II seesaw showing M Δ > M N .

  6. Background Reduction For Germanium Double Beta Decay Experiments

    SciTech Connect

    Gomez, H.; Cebrian, S.; Morales, J.; Villar, J. A.

    2007-03-28

    The new generation experiments to search for the neutrinoless double beta decay of 76Ge (Q{beta}{beta}=2039keV) using enriched germanium detectors, need to reach a background level of {approx}10-3 c keV-1 kg-1 y-1 in the Region of Interest (RoI: 2-2.1 MeV) that would have, for 70 kg of germanium enriched to 86% in 76Ge, 3 keV of FWHM and 5 years of measuring time, a sensitivity on the effective neutrino mass of {<=} 40 meV. To reduce the background level close to the value needed, we have to combine several techniques. Three of the most important points to study are: segmentation and granularity of the crystal and spatial resolution of the detector directly correlated with an offline Pulse Shape Analysis (PSA). Preliminary studies about these strategies for background reduction were developed during last months, obtaining some promising results.

  7. Herman Feshbach Prize in Theoretical Nuclear Physics Xiangdong Ji, University of Maryland PandaX-III: high-pressure gas TPC for Xe136 neutrinoless double beta decay at CJPL

    NASA Astrophysics Data System (ADS)

    Ji, Xiangdong; PandaX-III Collaboration

    2016-03-01

    The PandaX-III in China's Jinping Underground Lab is a new neutrinoless double beta decay experiment using Xe136 high-pressure gas TPC. The first phase of the experiment uses a 4 m3 gas detector with symmetric Micromegas charge readout planes. The gas TPC allows full reconstruction of the event topology, capable of distinguishing the two electron events from gamma background with high confidence level. The energy resolution can reach about 3% FWHM at the beta decay Q-value. The detector construction and the experimental lab is currently under active development. In this talk, the current status and future plan are reported.

  8. Cross Section Measurements of the 76Ge (n ,n' γ) Reaction

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Peters, E. E.; Prados-Estévez, F. M.; Ross, T. J.; McEllistrem, M. T.; Yates, S. W.; Vanhoy, J. R.

    2013-10-01

    Neutrinoless double-beta decay (0 νββ) is a topic of great current interest and, as such, is the focus of several experiments and international collaborations. Two of these experiments, Majorana and GERDA, are seeking evidence of 0 νββ in the decay of 76Ge, where the signal would appear as a sharp peak in the energy spectrum at the Q-value of the reaction plus a small amount of recoil energy, or 2039 keV. Due to the high sensitivity of such a measurement, knowledge of background lines is critical. A study of 76Ga β- decay into 76Ge revealed a 2040.70(25)-keV transition from the 3951.70(14)-keV level, which, if populated, could potentially be a background line of concern. In addition to β- decay from 76Ga, a potential population mechanism could be cosmic-ray-induced inelastic neutron scattering. Measurements of the neutron-induced cross section of the 3951.70-keV level have been performed utilizing the 76 Ge (n ,n' γ) reaction at the University of Kentucky at neutron energies ranging from 4.3 to 4.9 MeV. This material is based upon work is supported by the U.S. National Science Foundation under grant no. PHY-0956310.

  9. Nuclear Structure Studies of ^76Se and ^76Ge with the (n, n'γ) Reaction

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Chakraborty, A.; Kumar, A.; Peters, E. E.; Prados-Estévez, F. M.; McEllistrem, M. T.; Yates, S. W.

    2012-10-01

    Experimental confirmation of neutrinoless double-beta decay (0νββ) would provide evidence of physics beyond the standard model by identifying the neutrino as its own anti-particle, i.e., a Majorana particle. Furthermore, such a confirmation would yield the absolute mass scale of neutrinos, provided that the nuclear matrix elements involved in the caculation are understood to a high degree of accuracy. A favorite candidate in the search for 0νββ is the decay of ^76Ge to ^76Se, since ^76Ge can act as a source of the decay as well as a high-resolution detector for the resultant events. In order to increase our knowledge of the structural properties of these nuclei, excitation function and γ-ray angular distribution measurements utilizing the ^76Ge(n, n'γ) and ^76Se(n, n'γ) reactions were performed at the University of Kentucky at neutron energies ranging from 2.0 MeV to 4.0 MeV. These measurements yield information on level spins and parities, level lifetimes, transition multipolarities, and transition probabilites. These results will be discussed in the context of structural features such as mixed-symmetry states and shape coexistence.

  10. Review of modern double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Barabash, A. S.

    2015-10-01

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( < 0.46 eV) and a coupling constant of Majoron to neutrino ( < 1.3 . 10-5) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to at the level of ˜ 0.01-0.1 eV are discussed.

  11. Review of modern double beta decay experiments

    SciTech Connect

    Barabash, A. S.

    2015-10-28

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T{sub 1/2}(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈m{sub ν}〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈g{sub ee}〉 < 1.3 · 10{sup −5}) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈m{sub ν}〉 at the level of ∼ 0.01-0.1 eV are discussed.

  12. Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin

    2015-10-01

    To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  13. Neutron-Induced Reactions on Copper and Zero-Neutrino Double-Beta Decay Searches

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Kelley, John; Fallin, Brent; Finch, Sean; Howell, Calvin; Rusev, Gencho; Tonchev, Anton; Tornow, Werner

    2012-10-01

    Cross-section measurements of (n,xγ) reactions on ^natCu were carried out at TUNL using monoenergetic neutrons at six energies of En = 6, 8, 10, 12, 14, 16 MeV. These studies were performed to provide accurate cross-section data on materials abundant in experimental setups involving HPGe detectors used to search for rare events, like the neutrino-less double-beta decay of ^76Ge. Spallation and (α,n) neutrons are expected to cause the largest source of external background in the energy region of interest. At TUNL pulsed neutron beams were produced via the ^2H(d,n)^3He reaction and the deexcitation γ rays from the reaction ^natCu(n,xγ) were detected with clover HPGe detectors. Our cross-section data will be compared to theoretical calculations and to data recently obtained at LANL with a white neutron beam.

  14. Neutron induced radio-isotopes and background for Ge double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Chu, Pinghan; Majorana Collaboration

    2015-10-01

    Environmental neutrons, mostly produced by muons in the cosmic rays, might contribute backgrounds to the search for neutrinoless double beta decays. These neutrons can interact with materials and generate radio-isotopes, which can decay and produce radioactive backgrounds. Some of these neutron-induced isotopes have a signature of a time-delayed coincidence, allowing us to study these infrequent events. For example, such isotopes can decay by beta decay to metastable states and then decay by gamma decay to the ground state. Considering the time-delayed coincidence of these two processes, we can determine candidates for these neutron-induced isotopes in the data and estimate the flux of neutrons in the deep underground environment. In this report, we will list possible neutron-induced isotopes and the methodology to detect them, especially those that can affect the search for neutrinoless double beta decays in 76Ge. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  15. Neutron-capture cross-section measurements of 74Ge and 76Ge in the energy region 0.4-14.8 MeV for neutrinoless double β decay applications

    NASA Astrophysics Data System (ADS)

    Bhike, Megha; Tornow, Werner

    2013-10-01

    Fast neutron capture cross sections for the reactions 74Ge(n, γ)75Ge and 76Ge(n, γ)77Ge have been measured in the neutron energy region 0.4-14.8 MeV with the activation method. The results are important to identify backgrounds in the neutrinoless double- β decay experiments GERDA and MAJORANA, which use germanium as both source and detector. Isotopically enriched targets which consisted of 86% of 76Ge and 14% of 74Ge were irradiated with mono-energetic neutrons produced via 3H(p,n)3He, 2H(d,n)3He and 3H(d,n)4He reactions. The cross sections were determined relative to 197Au(n, γ)198Au, 115In(n,n')115mIn and 197Au(n,2n)196Au standard cross sections. The activities of the products were measured using high-resolution γ-ray spctroscopy. The present results are compared with the evaluated data from ENDF/B-VII.1 and TALYS.

  16. AMoRE: Collaboration for searches for the neutrinoless double-beta decay of the isotope of {sup 100}Mo with the aid of {sup 40}Ca{sup 100}MoO{sub 4} as a cryogenic scintillation detector

    SciTech Connect

    Khanbekov, N. D.

    2013-09-15

    The AMoRE (Advanced Mo based Rare process Experiment) Collaboration is planning to employ {sup 40}Ca{sup 100}MoO{sub 4} single crystals as a cryogenic Scintillation detector for studying the neutrinoless double-beta decay of the isotope {sup 100}Mo. A simultaneous readout of phonon and scintillation signals is performed in order to suppress the intrinsic background. The planned sensitivity of the experiment that would employ 100 kg of {sup 40}Ca{sup 100}MoO{sub 4} over five years of data accumulation would be T{sub 1/2}{sup 0{nu}} = 3 Multiplication-Sign 10{sup 26} yr, which corresponds to values of the effective Majorana neutrino mass in the range of Left-Pointing-Angle-Bracket m{sub {nu}} Right-Pointing-Angle-Bracket {approx} 0.02-0.06 eV.

  17. Simultaneous analysis of neutrinoless double beta decay and LHC pp-cross sections: limits on the left-right mixing angle

    NASA Astrophysics Data System (ADS)

    Civitarese, O.; Suhonen, J.; Zuber, K.

    2015-09-01

    The extension of the Standard Model of electroweak interactions, to accommodate massive neutrinos and/or right-handed currents, is one of the fundamental questions to answer in the cross-field of particle and nuclear physics. The consequences of such extensions would reflect upon nuclear decays, like the very exotic nuclear double-beta-decay, as well as upon high-energy proton-proton reactions of the type performed at the LHC accelerator. In this talk we shall address this question by looking at the results reported by the ATLAS and CMS collaborations, where the excitation and decay of a heavy-mass boson may be mediated by a heavy-mass neutrino in proton-proton reactions leading to two jets and two leptons, and by extracting limits on the left-right mixing, from the latest measurements of nuclear-double-beta decays reported by the GERDA and EXO collaborations.

  18. Possible usage of Cherenkov photons to reduce the background in a 136Xe neutrino-less double-beta decay experiment

    NASA Astrophysics Data System (ADS)

    Signorelli, G.; Dussoni, S.

    2016-07-01

    One of the main backgrounds in the search for 136Xe nutrino-less double-beta decay (0 νββ) is the signal from Compton scattering of photons with energy around the decay endpoint at 2.458 MeV. Electrons in liquid xenon emit scintillation light at 178 nm. Liquid xenon being extremely transparent to ultra violet light it is in principle possible to discriminate one particle events (such as the Compton background) from two particle events (double-beta decay signals) by the amount of Cherenkov radiation emitted. The identification of the Cherenkov photons may be performed by looking at the different time structure of the signal with respect to the scintillation, by selecting photons with wavelengths larger than the typical Xenon scintillation light, and by the different emission topology. A proof-of-principle study of this approach is presented here together with preliminary studies on possible detectors for the two light components at different wavelengths.

  19. Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches

    NASA Astrophysics Data System (ADS)

    Nakajima, Y.; Goldschmidt, A.; Matis, H. S.; Nygren, D.; Oliveira, C.; Renner, J.

    2015-11-01

    Liquid Xe TPCs are among the most popular choices for double beta decay and WIMP dark matter searches. Gaseous Xe has intrinsic advantages when compared to Liquid Xe, specifically, tracking capability and better energy resolution for double beta decay searches. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which are expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). These features may provide better tracking and energy resolution for double-beta decay searches. They are also expected to enhance columnar recombination for nuclear recoils, which can be used for searches for WIMP dark matter with directional sensitivity. We constructed a test ionization chamber and successfully measured scintillation and ionization yields at high precision with various Xe and TMA mixtures and pressures. We observed the Penning effect and an increase in recombination with the addition of TMA. However, many undesired features for dark matter searches, such as strong suppression of the scintillation light and no sign of recombination light, were also found. This work has been carried out within the context of the NEXT collaboration.

  20. Status and Perspectives of Double Beta Decay Searches

    NASA Astrophysics Data System (ADS)

    Zuber, K.

    2015-11-01

    Double beta decay is an extremely rare process and requires half-life measurements around 1020 years for the neutrino accompanied and well beyond that for the neutrinoless mode. The current status of the search will be discussed.

  1. The COBRA Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Dawson, J. V.

    2007-03-01

    The progress of the COBRA neutrinoless double beta decay experiment is discussed. Potential backgrounds are described. Estimates on the contamination levels of 214Bi in the detectors have been made using previously acquired low background data. New crystals with a different passivation material show an improved background count rate of approximately one order of magnitude.

  2. The COBRA Double Beta Decay Experiment

    SciTech Connect

    Dawson, J. V.

    2007-03-28

    The progress of the COBRA neutrinoless double beta decay experiment is discussed. Potential backgrounds are described. Estimates on the contamination levels of 214Bi in the detectors have been made using previously acquired low background data. New crystals with a different passivation material show an improved background count rate of approximately one order of magnitude.

  3. Double-beta decay with majoron emission in GERDA Phase I

    NASA Astrophysics Data System (ADS)

    Hemmer, Sabine

    2015-07-01

    Neutrinoless double-beta decay with emission of one or two majorons (0 νββχ( χ)) is predicted by several beyond-Standard-Model theories. This article reviews the results of a search for 0 νββχ( χ) of 76Ge using data from the Germanium Detector Array (GERDA) experiment, located underground at the INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The analysis comprised data with an exposure of 20.3 kg·yr from the first phase of the experiment. No indication of contributions to the observed energy spectra was detected for any of the majoron models. The lower limit on the half-life for the ordinary majoron model (spectral index n = 1 was determined to be T {1/2/0 νβ } > 4.2 · 1023 yr (90% quantile). This limit and the limits derived for the other majoron modes constitute the most stringent limits on 0 νββχ( χ) decay of 76Ge measured to date.

  4. The cosmogenic induced background estimation for the MAJORANA DEMONSTRATOR enriched 76Ge

    NASA Astrophysics Data System (ADS)

    White, Brandon; Majorana Collaboration

    2016-03-01

    Neutrino-less double beta (0 νββ) decay experiments probe for such rare events that the suppression of backgrounds are major experimental concerns. Cosmogenic induced isotopes have the potential to be a major background for such experiments. For the MAJORANA DEMONSTRATOR Experiment 76Ge isotope is used as both detector and source. The isotope 68Ge is cosmogenically produced when the Ge is on the Earth's surface. The decay of this isotope can mimic events in the region of interest. The experiment is located at the 4850 foot level at the Sanford Underground Research Facility in Lead, South Dakota to suppress cosmogenic activation. In this talk I will present the calculations of cosmogenic background for the enriched 76Ge materials used in the MAJORANA DEMONSTRATOR HPGe detectors. The activation is determined by the surface exposure from the time of production, storage, and delivery of the enriched Ge detectors to the underground experimental site. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and the Sanford Underground Research Faci.

  5. Nuclear-Structure Data Relevant to Neutinoless-Double-Beta-Decay Matrix Elements

    NASA Astrophysics Data System (ADS)

    Kay, Benjamin

    2015-10-01

    An observation of neutrinoless double beta decay is one of the most exciting prospects in contemporary physics. It follows that calculations of the nuclear matrix elements for this process are of high priority. The change in the wave functions between the initial and final states of the neutrinoless-double-beta-decay candidates 76Ge-->76Se, 100Mo-->100Ru, 130Te-->130Xe, and 136Xe-->136Ba have been studied with transfer reactions. The data are focused on the change in the occupancies of the valence orbitals in the ground states as two neutrons decay into two protons. The results set a strict constraint on any theoretical calculations describing this rearrangement and thus on the magnitude of the nuclear matrix elements for this process, which currently exhibit uncertainties at the factor of 2-4 level. Prior to these measurements there were limited experimental data were available A = 76 and 100 systems, and very limited data for the A = 130 and 136 systems, in a large part due to the gaseous Xe isotopes involved. The uncertainties on most of these data are estimated to range from 0.1-0.3 nucleons. The program started with the A = 76 system, with subsequent calculations, modified to reproduce the experimental occupancies, exhibiting a significant reduction in the discrepancy between various models. New data are available for the A = 100 , 130, and 136 systems. I review the program, making detailed comparisons between the latest theoretical calculations and the experimental data where available. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.

  6. Search for double beta decay with HPGe detectors at the Gran Sasso underground laboratory

    NASA Astrophysics Data System (ADS)

    Chkvorets, Oleg

    2008-12-01

    Neutrinoless double-beta decay is practically the only way to establish the Majorana nature of the neutrino mass and its decay rate provides a probe of an effective neutrino mass. Double beta experiments are long-running underground experiments with specific challenges concerning the background reduction and the long term stability. These problems are addressed in this work for the Heidelberg-Moscow (HdM), GENIUS Test Facility (TF) and GERDA experiments. The HdM experiment collected data with enriched 76Ge high purity (HPGe) detectors from 1990 to 2003. An improved analysis of HdM data is presented, exploiting new calibration and spectral shape measurements with the HdM detectors. GENIUS-TF was a test-facility that verified the feasibility of using bare germanium detectors in liquid nitrogen. The first year results of this experiment are discussed. The GERDA experiment has been designed to further increase the sensitivity by operating bare germanium detectors in a high purity cryogenic liquid, which simultaneously serves as a shielding against background and as a cooling media. In the preparatory stage of GERDA, an external background gamma flux measurement was done at the experimental site in the Hall A of the Gran Sasso laboratory. The characterization of the enriched detectors from the HdM and IGEX experiments was performed in the underground detector laboratory for the GERDA collaboration. Long term stability measurements of a bare HPGe detector in liquid argon were carried out. Based on these measurements, the first lower limit on the half-life of neutrinoless double electron capture of 36Ar was established to be 1.85*10^18 years at 68% C.L.

  7. Double Beta Decay Measurement with COBRA

    NASA Astrophysics Data System (ADS)

    Wilson, Jeanne R.

    2011-12-01

    The COBRA experiment aims to use a large array of CdZnTe semiconductor detectors to search for neutrinoless double beta decay. Extensive simulation studies and data collected with a small proto-type experiment have been used to address the major design specifications for a large scale experiment sensitive to 116Cd half-lives in excess of 1026 years. The current and future prospects of the COBRA experiment are presented.

  8. Characterization of the energy resolution and the tracking capabilities of a hybrid pixel detector with CdTe-sensor layer for a possible use in a neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Filipenko, Mykhaylo; Gleixner, Thomas; Anton, Gisela; Durst, Jürgen; Michel, Thilo

    2013-04-01

    Many different experiments are being developed to explore the existence of the neutrinoless double beta decay (0 νββ) since it would imply fundamental consequences for particle physics. In this work we present results on the evaluation of Timepix detectors with cadmium-telluride sensor material to search for 0 νββ in 116Cd. This work was carried out with the COBRA collaboration and the Medipix collaboration. Due to the relatively small pixel dimension of 110×110×1000 μm3 the energy deposited by particles typically extends over several detector pixels leading to a track in the pixel matrix. We investigated the separation power regarding different event-types like α-particles, atmospheric muons, single electrons and electron-positron pairs produced at a single vertex. We achieved excellent classification power for α-particles and muons. In addition, we achieved good separation power between single electron and electron-positron pair production events. These separation abilities indicate a very good background reduction for the 0 νββ search. Further, in order to distinguish between 2 νββ and 0 νββ, the energy resolution is of particular importance. We carried out simulations which demonstrate that an energy resolution of 0.43 % is achievable at the Q-value for 0 νββ of 116Cd at 2.814 MeV. We measured an energy resolution of 1.6 % at a nominal energy of 1589 keV for electron-positron tracks which is about two times worse that predicted by our simulations. This deviation is probably due to the problem of detector calibration at energies above 122 keV which is discussed in this paper as well.

  9. Heidelberg-Moscow {beta}{beta} experiment with {sup 76}Ge: Full setup with five detectors

    SciTech Connect

    Guenther, M.; Hellmig, J.; Heusser, G.; Hirsch, M.; Klapdor-Kleingrothaus, H.V.; Maier, B.; Paes, H.; Petry, F.; Ramachers, Y.; Strecker, H.; Voellinger, M.; Balysh, A.; Belyaev, S.T.; Demehin, A.; Gurov, A.; Kondratenko, I.; Kotelnikov, D.; Lebedev, V.I.; Mueller, A.

    1997-01-01

    The full setup of the Heidelberg-Moscow double {beta} decay experiment is presented. This experiment gives at present the most stringent upper bound, improving the neutrino mass limit into the sub-eV range. Out of 19.2 kg of 86{percent} enriched {sup 76}Ge five crystals were grown with a total mass of 11.51 kg. Since February 1995 all five detectors, corresponding to 10.96 kg active mass, are in regular operation in the Gran Sasso underground laboratory, four of them in a common shield. No signal is observed for the neutrinoless double {beta} decay (0{nu}{beta}{beta}). The measured data from the first three enriched detectors with a statistical significance of 13.60 kgyr result in a new half-life limit of T{sub 1/2}(0{sup +}{r_arrow}0{sup +}){gt}7.4{times}10{sup 24} yr (90{percent} C.L.). With this limit a Majorana mass of the neutrinos larger than 0.6 eV (90{percent} C.L.) is excluded. From the data taken in the previously operated setup with three enriched detectors in a common shielding and a statistical significance of 10.58 kgyr new results are extracted for the two neutrino double {beta} decay (2{nu}{beta}{beta}) of {sup 76}Ge. The procedure of a quantitative and model-independent description of the background via a Monte Carlo simulation is outlined in some detail. The combined result is T{sub 1/2}{sup 2{nu}}=[1.77{sub {minus}0.01}{sup +0.01}(stat){sub {minus}0.11}{sup +0.13}(sys)]{times}10{sup 21} yr. Further on the results concerning new Majoron models and the impact on SUSY parameters are briefly reviewed. Future improvements on the background with the application of digital pulse shape analysis are discussed and an outlook on the future of {beta}{beta} research is given. {copyright} {ital 1996} {ital The American Physical Society}

  10. Future Challenges for Double Beta Decay Experiments

    NASA Astrophysics Data System (ADS)

    Elliott, Steven

    2015-10-01

    Neutrino oscillation experiments have shown that at least one neutrino has a mass greater than 50 meV. In the inverted hierarchy pattern of neutrino masses, one would expect an effective Majorana neutrino mass of 15 meV or greater. This fact has led to a strong resurgence of interest in neutrinoless double beta decay experiments that can reach this mass target. If this rare nuclear decay process exists it would demonstrate that Lepton number conservation is violated, that neutrinos are their own anti-particles and the decay rate would give an indication of the neutrino mass. This presentation will summarize the double beta decay experimental program with a focus on the technical challenges that will be faced.

  11. New generation of double beta decay experiments: are there any limitations?

    SciTech Connect

    Barabash, A. S.

    2011-12-16

    New generation of experiments to search for neutrinoless double beta decay with sensitivity to effective Majorana neutrino mass on the level of {approx}3-5 meV is discussed. Possible restrictions in achievement of this sensitivity such as: possibility to produce large amount of enriched isotopes, possibility to reach of a very low level of background, energy resolution and possible cost of experiments are considered. It is shown that for realization of so ambitious project 10 tons (or more) of enriched isotope is required. Background index should be on the level {<=}10{sup -5}-10{sup -6} c/kg{center_dot}keV{center_dot}y. In addition, the energy resolution of the detector should be no worse than 1-2%. It is shown that {sup 130}TeO{sub 2} low temperature bolometer could be the most realistic candidate for such an experiment. Under certain conditions experiments with {sup 76}Ge, {sup 100}Mo and {sup 136}Xe can be realized too.

  12. Particle and nuclear physics parameters—how do they affect the tracks of double beta events in a germanium detector, and their separation from gamma events

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, H. V.; Krivosheina, I. V.; Titkova, I. V.

    2006-01-01

    The sizes of tracks of events of neutrinoless double beta decay in a germanium detector depend on particle physics and nuclear physics parameters such as neutrino mass, right-handed current parameters, etc., and nuclear matrix elements. The knowledge of this dependence is of importance, since the key to probe the existence of 0 νββ decay beyond observation of a signal at the Q value of the process, Qββ, is the discrimination of ββ events from background γ events (or other events), in almost any double beta decay experiment (see [H.V. Klapdor-Kleingrothaus, I.V. Krivosheina, A. Dietz, et al., Phys. Lett. B 586 (2004) 198; H.V. Klapdor-Kleingrothaus, A. Dietz, I.V. Krivosheina, et al., Nucl. Instrum. Methods A 522 (2004) 371]). In this Letter for the first time Monte Carlo simulations of neutrino-accompanied (2 νββ) and neutrinoless double beta decay (0 νββ) events, and of various kinds of background processes such as multiple and other γ interactions are reported for a Ge detector. The time history of the evolution of the individual events is followed and a systematic study has been performed of the sizes of the events (volumes in the detector inside which the energy of the event is released which determine the observed signals). Effects of the angular correlations of the two electrons in ββ decay, which again depend on the above nuclear and (for 0 νββ decay) particle physics parameters, are taken into account and have been calculated for this purpose for 76Ge for the first time on basis of the experimental half-life and of realistic nuclear matrix elements. A brief outlook is given on the potential of future experiments with respect to determination of the particle physics parameters , < λ >, < η >.

  13. The NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Laing, A.; NEXT Collaboration

    2016-05-01

    NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (ββ0v) decay experiment at Laboratorio Subterraneo de Canfranc (LSC). It is an electroluminescent Time Projection Chamber filled with high pressure 136Xe gas with separated function capabilities for calorimetry and tracking. Energy resolution and background suppression are the two key features of any neutrinoless double beta decay experiment. NEXT has both good energy resolution (< 1% FWHM) and an extra handle for background identification provided by track reconstruction. We expect a background rate of 4 × 10-4 counts keV-1 kg-1 yr-1, and a sensitivity to the Majorana neutrino mass of between 80-160 meV (depending on NME) after a run of 3 effective years of the 100 kg scale NEXT-100 detector. The initial phase of NEXT-100, called NEW, is currently being commissioned at LSC. It will validate the NEXT background rate expectations and will make first measurements of the two neutrino ββ2v mode of 136Xe. Furthermore, the NEXT technique can be extrapolated to the tonne scale, thus allowing the full exploration of the inverted hierarchy of neutrino masses. These proceedings review NEXT R&D results, the status of detector commissioning at LSC and the NEXT physics case.

  14. Double-beta decay: Some recent results and developments

    NASA Astrophysics Data System (ADS)

    Avignone, F. T.

    A brief review and status of theoretical issues associated with double-beta decay (ββ-decay) is given. The final results of the measurement of 2ν ββ-decay of 100Mo to the first excited 0 + state in 100Ru are presented prior to publication. Corrections to the earlier PNL/USC/ITEP/YPI measurement of 2ν ββ-decay of 76Ge are also given prior to publication. Finally, a status report and first results of the phase-I of the International Germanium Experiment (IGEX) are presented.

  15. Theoretical challenges in Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Stoica, Sabin

    2016-05-01

    The study of the double beta decay (DBD), particularly the neutrino less decay mode, is of great interest for testing the lepton number conservation (LNC) and getting information about neutrino properties, as the neutrinos character (Dirac or Majorana particles?), their absolute mass and hierarchy, etc. [1]-[2]. To make predictions of the DBD lifetimes and put constraints on the neutrino parameters, one needs accurate calculations of the nuclear matrix elements (NME) and phase space factors (PSF) entering the DBD lifetime expressions. In this paper I present recent calculations of these quantities, performed with approaches developed by our group. Then, I compare the theoretical predictions for the two-neutrino (2v) DBD lifetimes, for the most experimentally interesting nuclei, with the experimental ones, and comment on the reliability of the neutrinoless (0v) DBD calculations.

  16. Theoretical investigation of the dependence of double beta decay tracks in a Ge detector on particle and nuclear physics parameters and separation from gamma ray events

    SciTech Connect

    Klapdor-Kleingrothaus, H.V.; Krivosheina, I.V.; Titkova, I.V.

    2006-01-01

    The sizes of tracks of events of neutrinoless double-beta decay in a Germanium detector depend on particle physics and nuclear physics parameters such as neutrino mass, right-handed current parameters, etc., and nuclear matrix elements. In this paper for the first time Monte Carlo simulations of neutrino-accompanied (2{nu}{beta}{beta}) and neutrinoless double-beta decay (0{nu}{beta}{beta}) events, and of various kinds of background processes such as multiple and other {gamma} interactions are reported for a Ge detector. The time history of the evolution of the individual events is followed and the sizes of the events (partial volumes in the detector inside which the energy of the event is released) are investigated. Effects of the angular correlations of the two electrons in {beta}{beta} decay, which again depend on the above nuclear and (for 0{nu}{beta}{beta} decay) on particle physics parameters, are taken into account and have been calculated for this purpose for the first time on basis of the experimental half-life of {sup 76}Ge and of realistic nuclear matrix elements. The sizes determine, together with the location of the events in the detector, the pulse shapes to be observed. It is shown for {beta}{beta} decay of {sup 76}Ge, that {beta}{beta} events should be selectable with high efficiency by rejecting large size (high multiplicity) {gamma} events. Double-escape peaks of similar energy of {gamma} lines show concerning their sizes similar behavior as 0{nu}{beta}{beta} events, and in that sense can be of some use for corresponding 'calibration' of pulse shapes of the detector. The possibility to distinguish {beta}{beta} events from {gamma} events is found to be essentially independent of the particle physics parameters of the 0{nu}{beta}{beta} process. A brief outlook is given on the potential of future experiments with respect to determination of the particle physics parameters ,<{lambda}>,<{eta}>.

  17. Results of the double beta decay experiment NEMO-3

    SciTech Connect

    Tretyak, V. I.; Collaboration: NEMO-3 Collaboration

    2013-12-30

    The double beta decay experiment NEMO-3 has taken data from February 2003 to January 2011. The two-neutrino decay half lives were measured for seven different isotopes ({sup 100}Mo, {sup 82}Se, {sup 116}Cd, {sup 150}Nd, {sup 96}Zr, {sup 48}Ca and {sup 130}Te). No evidence for neutrinoless double beta decay is observed. The 0νββ half-life limits are found to be T{sub 1/2}{sup 0ν}({sup 100}Mo)>1.0×10{sup 24}yr(90%C.L.) and T{sub 1/2}{sup 0ν}({sup 82}Se)>3.2×10{sup 23}yr(90%C.L.)

  18. A Search for Lorentz-Violation in Double Beta Decay with EXO-200

    NASA Astrophysics Data System (ADS)

    Johnson, Tessa; EXO-200 Collaboration

    2015-10-01

    The Standard-Model Extension (SME) framework assumes Lorentz-violation at the Planck scale, a result of certain theories uniting quantum mechanics to General Relativity. Lorentz-violating operators are added to the current Standard Model, potentially producing effects that could be observed on a macroscopic scale, for instance altering the standard spectrum of double beta decay. The EXO-200 experiment uses 175 kg of enriched liquid xenon to search for neutrinoless double beta decay in 136Xe, and the low background and high precision of the experiment create a good platform to search for other phenomena in double beta decay. The results of a search for deviations to the two-neutrino double beta decay spectrum of 136Xe that would indicate neutrino coupling to a Lorentz-violating operator in the SME are presented.

  19. The CUORICINO and CUORE double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Ardito, R.; Arnaboldi, C.; Artusa, D. R.; Avignone, F. T.; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J. W.; Bellini, F.; Brofferio, C.; Bucci, C.; Capelli, S.; Capozzi, F.; Carbone, L.; Cebrian, S.; Clemenza, M.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; de Waard, A.; Diemoz, M.; Dolinski, M.; Farach, H. A.; Ferroni, F.; Fiorini, E.; Freedman, S. J. F.; Frossati, G.; Gargiulo, C.; Giuliani, A.; Gorla, P.; Guardincerri, E.; Gutierrez, T. D.; Haller, E. E.; Heeger, K. M.; Irastorza, I. G.; Longo, E.; Maruyama, R.; Morganti, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; Xu, Nu; Olivieri, E.; Ottonello, P.; Pallavicini, M.; Palmieri, E.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Risegari, L.; Rosenfeld, C.; Sangiorgio, S.; Sisti, M.; Smith, A. R.; Torres, L.; Ventura, G.; Zanotti, L.

    2006-07-01

    After an introduction on the various experimental techniques to be adopted in searches for double beta decay, the new approach based on the use of cryogenic low temperature detectors is described. The present results are reported on the limit for neutrinoless double beta decay of 130Te obtained with the large bolometric detector CUORICINO. This setup consists of 44 cubic crystals of natural TeO 2 with 5 cm sides and 18 crystals of 3×3×6 cm 3. Four of these latter crystals are made with isotopically enriched materials: two in 128Te and two others in 130Te. With a sensitive mass of 40.7 kg, this array is by far the most massive running cryogenic detector. The array is operated at a temperature of ˜10 mK in a dilution refrigerator under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. The counting rate in the region of neutrinoless double beta decay is 0.18±0.02 counts keV -1 kg -1 y -1, among the lowest in this type of experiment. No evidence for neutrinoless double beta decay is found. The corresponding lower limit for the lifetime of this process is 2×10 24 years at 90% C.L. The resultant upper limit on the effective neutrino mass ranges between 0.2 and 1.0 eV, depending on the theoretically calculated nuclear matrix elements. This constraint is the most restrictive one, except for those obtained with Ge diodes, and is comparable to them. The second part of this report is devoted to the present status of the construction of the larger experiment CUORE (Cryogenic Underground Observatory for Rare Events) formed from 988 bolometers with a cubic TeO 2 absorber of size 5×5×5 cm 3, with a total mass of ˜750 kg. We present technical details of the CUORE setup as well as of its location and our efforts to reduce radioactive backgrounds.

  20. Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200

    SciTech Connect

    Ackerman, N.; Aharmim, B.; Auger, M.; Auty, D.J.; Barbeau, P.S.; Barry, K.; Bartoszek, L.; Beauchamp, E.; Belov, V.; Benitez-Medina, C.; Breidenbach, M.; Burenkov, A.; Cleveland, B.; Conley, R.; Conti, E.; Cook, J.; Cook, S.; Coppens, A.; Counts, I.; Craddock, W.; Daniels, T.; /more authors..

    2012-09-14

    We report the observation of two-neutrino double-beta decay in {sup 136}Xe with T{sub 1/2} = 2.11 {+-} 0.04(stat) {+-} 0.21(syst) x 10{sup 21} yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for {sup 136}Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.

  1. Limits on sterile neutrino contributions to neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Barea, J.; Kotila, J.; Iachello, F.

    2015-11-01

    Nuclear matrix elements (NME) for exchange of arbitrary mass neutrinos are calculated in the interacting boson model (IBM-2). By combining the NME with the phase space factors (PSF), expected half-lives for neutrinos of mass mN and coupling Ue N are estimated. Limits on sterile neutrinos with masses in the eV, keV, MeV-GeV, and TeV range are given.

  2. Maki-Nakagawa-Sakata parameters from neutrino oscillations, single beta decay, and double beta decay

    SciTech Connect

    Matsuda, K.; Takeda, N.; Fukuyama, T.; Nishiura, H.

    2001-07-01

    We examine the constraints on the Maki-Nakagawa-Sakata lepton mixing matrix from the present and future experimental data of neutrino oscillation, tritium beta decay, and neutrinoless double beta decay for the Majorana neutrinos. We show that the small mixing angle solutions for solar neutrino problem are disfavored for small averaged mass ({l_angle}m{sub {nu}}{r_angle}) of neutrinoless double beta decay ({le}0.01 eV) in the inverse neutrino mass hierarchy scenario. This is the case even in the normal mass hierarchy scenario except for a very restrictive value of the averaged neutrino mass ({ovr m{sub {nu}}}) of single beta decay. The lower mass bound for {ovr m{sub {nu}}} is given from the present neutrino oscillation data. We obtain some relations between {l_angle}m{sub {nu}}{r_angle} and {ovr m{sub {nu}}}. The constraints on the Majorana CP violating phases are also given.

  3. The Milano-Gran Sasso double beta decay experiment: toward a 20-crystal array

    NASA Astrophysics Data System (ADS)

    Alessandrello, A.; Brofferio, C.; Bucci, C.; Camin, D. V.; Cremonesi, O.; Fiorini, E.; Giuliani, A.; Nucciotti, A.; Pavan, M.; Pessina, G.; Previtali, E.; Zanotti, L.

    1996-02-01

    TeO 2 thermal detectors are being used by the Milano group to search for neutrinoless double beta decay of 130Te. An upper limit for neutrinoless decay half life of 2.1 × 10 22 yr at 90% CL obtained with a 334 g TeO 2 detector has been previously reported. To improve the sensitivity of the experiment an array of twenty 340 g TeO 2 crystals will be realised in the next future. As a first step toward the realisation of that experiment a 4 crystal detector has been tested in the Gran Sasso refrigerator. Detector performances, data acquisition and analysis are discussed.

  4. Double Beta Decay Experiments: Present Status and Prospects for the Future

    NASA Astrophysics Data System (ADS)

    Barabash, A. S.

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( < 0.46 eV) and a coupling constant of Majoron to neutrino ( < 1.3 × 10-5) are obtained. In the second part of the review prospects of search for the neutrinoless double beta decay in new experiments with sensitivity to at the level of ∼ (0.01-0.1) eV are discussed. The main attention is paid to experiments of CUORE, GERDA, MAJORANA, EXO, KamLAND-Zen-2, SuperNEMO and SNO+. Possibilities of low-temperature scintillating bolometers on the basis of inorganic crystals (ZnSe, ZnMoO4, Li2MoO4, CaMoO4 and CdWO4) are considered too.

  5. Study of Double Beta Decay of {sup 48}Ca by CANDLES

    SciTech Connect

    Umehara, S.; Kishimoto, T.; Ogawa, I.; Matsuoka, K.; Ito, G.; Yasuda, K.; Kakubata, H.; Miyashita, M.; Nomachi, M.; Ajimura, S.; Tamagawa, Y.; Fushimi, K.; Hazama, R.; Ohsumi, H.; Okada, K.; Yoshida, S.; Fujii, Y.

    2010-05-12

    CANDLES is the project to search for neutrino-less double beta decay (0nubetabeta) of {sup 48}Ca. The observation of 0nubetabeta will prove existence of a massive Majorana neutrino. We have developed the new detector system CANDLES which features CaF{sub 2}(pure) scintillators. Here expected performances of the system for background rejection are presented. It is also described current status of development for the detector system.

  6. Radiopurity control in the NEXT-100 double beta decay experiment

    SciTech Connect

    Álvarez, V.; Cárcel, S.; Cervera, A.; Díaz, J.; Ferrario, P.; Gil, A.; Gómez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; Lorca, D.; Martín-Albo, J.; Martínez, A.; Monrabal, F.; Muñoz Vidal, J.; Nebot-Guinot, M.; Rodríguez, J.; Serra, L.; Simón, A.; Sofka, C.; Sorel, M.; and others

    2013-08-08

    An extensive material screening and selection process is underway in the construction of the 'Neutrino Experiment with a Xenon TPC' (NEXT), intended to investigate neutrinoless double beta decay using a high-pressure xenon gas TPC filled with 100 kg of Xe enriched in {sup 136}Xe. Determination of the radiopurity levels of the materials is based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterráneo de Canfranc (Spain) and also on Glow Discharge Mass Spectrometry. Materials to be used in the shielding, pressure vessel, electroluminescence and high voltage components and energy and tracking readout planes have been already taken into consideration. The measurements carried out are presented, describing the techniques and equipment used, and the results obtained are shown, discussing their implications for the NEXT experiment.

  7. Search for double beta decay of 116Cd with enriched 116CdWO4 crystal scintillators (Aurora experiment)

    NASA Astrophysics Data System (ADS)

    Danevich, F. A.; Barabash, A. S.; Belli, P.; Bernabei, R.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Chernyak, D. M.; d’Angelo, S.; Incicchitti, A.; Kobychev, V. V.; Konovalov, S. I.; Laubenstein, M.; Mokina, V. M.; Poda, D. V.; Polischuk, O. G.; Shlegel, V. N.; Tretyak, V. I.; Umatov, V. I.

    2016-05-01

    The Aurora experiment to investigate double beta decay of 116 Cd with the help of 1.162 kg cadmium tungstate crystal scintillators enriched in 116 Cd to 82% is in progress at the Gran Sasso Underground Laboratory. The half-life of 116 Cd relatively to the two neutrino double beta decay is measured with the highest up-to-date accuracy T1/2 = (2.62 ± 0.14) × 1019 yr. The sensitivity of the experiment to the neutrinoless double beta decay of 116 Cd to the ground state of 116 Sn is estimated as T1/2 ≥ 1.9 × 1023 yr at 90% CL, which corresponds to the effective Majorana neutrino mass limit (mv) ≤ (1.2 — 1.8) eV. New limits are obtained for the double beta decay of 116 Cd to the excited levels of 116 Sn, and for the neutrinoless double beta decay with emission of majorons.

  8. Double Beta Decay in Xenon-136. Measuring the Neutrino-Emitting Mode and Searching for Majoron-Emitting Modes

    SciTech Connect

    Herrin, Steven

    2013-06-01

    Observations of neutrino flavor oscillations have demonstrated that neutrinos have mass. Since the discovery of these oscillations, much progress has been made at mea- suring the neutrino mass-squared differences and lepton mixing angles that character- ize them. However, the origin and absolute scale of neutrino masses remain unknown. Unique among fermions, neutrinos can be Majorana particles, which could provide an explanation for neutrino masses. Discovery of a hypothetical process known as neutrinoless double beta decay would show that neutrinos are Majorana particles and determine the mass scale for neutrinos. The Enriched Xenon Observatory (EXO) is a series of experiments searching for the neutrinoless double beta decay of 136Xe. The first experiment, EXO-200, began operation in 2011 and makes use of 200 kg of xenon enriched to 80.6% in 136Xe. The analysis presented here makes use of data from EXO-200 to obtain a more precise measurement of the half-life for the two-neutrino-emitting mode of double beta decay than previously reported. The analysis also sets limits on the half-lives for exotic, Majoron-emitting modes of neutrinoless double beta decay. Data from EXO-200 is also used to produce a measurement of the cosmic muon flux at the WIPP under- ground site where EXO-200 is located.

  9. Double-Beta Decay at TUNL

    NASA Astrophysics Data System (ADS)

    Kidd, Mary

    2007-10-01

    Studying double-beta decay at Triangle Universities Nuclear Laboratory (TUNL) is perhaps one of the most promising ways to pinpoint the neutrino mass. What they do not mention is that to study double-beta decay, you probably have to become a certified miner, and if you have a fear of goats, you should stay away. In this talk, I will tell you some of my experiences as a TUNL graduate student, and how I am now nearly qualified for a job in the mining industry.

  10. The Majorana Zero-Neutrino Double-Beta Decay Experiment White Paper

    SciTech Connect

    Gaitskell, R.; Barabash, A.; Konovalov, S.; Stekhanov, V.; Umatov,, V.; Brudanin, V.; Egorov, S.; Webb, J.; Miley, Harry S.; Aalseth, Craig E.; Anderson, Dale N.; Bowyer, Ted W.; Brodzinski, Ronald L.; Jordan, David B.; Kouzes, Richard T.; Smith, Leon E.; Thompson, Robert C.; Warner, Ray A.; Tornow, W.; Young, A.; Collar, J. I.; Avignone, Frank T.; Palms, John M.; Doe, P. J.; Elliott, Steven R.; Kazkaz, K.; Robertson, Hamish; Wilkerson, John

    2002-03-07

    The goal of the Majorana Experiment is to determine the effective Majorana masss of the eletron neutrino. Detection of the neutrino mass implied by oscillation results in within our grasp. This exciting physics goal is best pursued using double-beta decay of germanium because of the historical and emerging advances in eliminating competing signals from radioactive backgrounds. The Majorana Experiment will consist of a large mass of 76Ge in the form of high-resolution detectors deep underground, searching for a sharp peak at the BB endpoint. We present here an overview of the entire project in order to help put in perspective the scope, the level and technial risk, and the readiness of the Collaboration to begin the undertaking.

  11. Shell-Model Calculations of Two-Nucleon Tansfer Related to Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Brown, Alex

    2013-10-01

    I will discuss theoretical results for two-nucleon transfer cross sections for nuclei in the regions of 48Ca, 76Ge and 136Xe of interest for testing the wavefuntions used for the nuclear matrix elements in double-beta decay. Various reaction models are used. A simple cluster transfer model gives relative cross sections. Thompson's code Fresco with direct and sequential transfer is used for absolute cross sections. Wavefunctions are obtained in large-basis proton-neutron coupled model spaces with the code NuShellX with realistic effecive Hamiltonians such as those used for the recent results for 136Xe [M. Horoi and B. A. Brown, Phys. Rev. Lett. 110, 222502 (2013)]. I acknowledge support from NSF grant PHY-1068217.

  12. Average and recommended half-life values for two neutrino double beta decay: Upgrade-2013

    SciTech Connect

    Barabash, A. S.

    2013-12-30

    All existing positive results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of {sup 48}Ca, {sup 76}Ge, {sup 82}Se, {sup 96}Zr, {sup 100}Mo, {sup 100}Mo−{sup 100}Ru (0{sub 1}{sup +}), {sup 116}Cd, {sup 130}Te, {sup 136}Xe, {sup 150}Nd, {sup 150}Nd−{sup 150}Sm (0{sub 1}{sup +}) and {sup 238}U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of {sup 128}Te and {sup 130}Ba are proposed. I recommend the use of these results as the most currently reliable values for half-lives.

  13. SNO+ status and plans for double beta decay search and other neutrino studies

    NASA Astrophysics Data System (ADS)

    Andringa, S.; SNO+ Collaboration

    2016-01-01

    SNO+ is a multi-purpose Neutrino Physics experiment, succeeding to the Sudbury Neutrino Observatory by replacing heavy water with liquid scintillator, which can also be loaded with large quantities of double-beta decaying isotope. The scientific goals of SNO+ are the search for neutrinoless double-beta decay, the study of solar neutrinos and of anti-neutrinos from nuclear reactors and the Earth's natural radioactivity, as well as supernovae neutrinos. The installation of the detector at SNOLAB is being completed and commissioning has already started with a dry run. The detector will soon be filled with water and, later, with scintillator. Here we highlight the main detector developments and address the several Physics analysis being prepared for the several planned SNO+ runs.

  14. Measurement of the Double-Beta Decay Half-life of {sup 136}Xe in KamLAND-Zen

    SciTech Connect

    KamLAND-Zen Collaboration; Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K.; Kato, R.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakada, T.; Nakamura, K.; Obata, A.; Oki, A.; Ono, Y.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yamada, S.; Yoshida, H.; Kozlov, A.; Yoshida, S.; Banks, T. I.; Detwiler, J. A.; Freedman, S. J.; Fujikawa, B. K.; Han, K.; O'Donnell, T.; Berger, B. E.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Enomoto, S.; Decowski, M. P.

    2012-01-23

    We present results from the KamLAND-Zen double-beta decay experiment based on an exposure of 77.6 days with 129 kg of {sup 136}Xe. The measured two-neutrino double-beta decay half-life of {sup 136}Xe is T{sup 2{nu}}{sub 1/2} = 2:38 {+-} 0:02(stat) {+-}0.14(syst) x10{sup 21} yr, consistent with a recent measurement by EXO-200. We also obtain a lower limit for the neutrinoless double-beta decay half-life, T{sup 0{nu}}{sub 1/2} > 5.7 x 10{sup 24} yr at 90% C.L.

  15. The COBRA double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Oldorf, C.; Cobra Collaboration

    2012-08-01

    The COBRA experiment is searching for double beta decay using CdZnTe semiconductor detectors. The main focus is on the isotope 116Cd. In addition to pure energy measurements, pixelisation allows also for tracking capabilities. This kind of semiconductor tracker is unique in the field. The current status of the experiment is shown including the latest half-life limits.

  16. Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States

    NASA Astrophysics Data System (ADS)

    Finch, Sean W.

    Two separate experimental searches for second-order weak nuclear decays to excited final states were conducted. Both experiments were carried out at the Kimballton Underground Research Facility to provide shielding from cosmic rays. The first search is for the two-neutrino double-beta decay of 96Zr to excited final states of the daughter nucleus, 96Mo. As a by product of this experiment, the beta decay of 96Zr was also investigated. Two coaxial high-purity germanium detectors were used in coincidence to detect gamma rays produced by the daughter nucleus as it de-excited to the ground state. After collecting 1.92 years of data with 17.91 g of enriched 96Zr, half-life limits at the level of 10 20 yr were produced. Measurements of this decay are important to test neutrinoless double-beta decay nuclear matrix element calculations, which are necessary to extract the neutrino mass from a measurement of the neutrinoless double-beta decay half-life. The second experiment is a search for the resonantly-enhanced neutrinoless double-electron capture decay of 156Dy to excited states in 156Gd. Double-electron capture is a possible experimental alternative to neutrinoless-double beta decay, which could distinguish the Dirac or Majorana nature of the neutrino. Two clover high-purity germanium detectors were used in coincidence to investigate the decay. A 213.5 mg enriched 156Dy sample was observed for 0.635 year, producing half-life limits of 10 17 yr. The limits produced by both of these experiments are currently the most stringent limits available for these decays.

  17. A scintillating bolometer array for double beta decay studies: The LUCIFER experiment

    NASA Astrophysics Data System (ADS)

    Gironi, L.

    2016-07-01

    The main goal of the LUCIFER experiment is to study the neutrinoless double beta decay, a rare process allowed if neutrinos are Majorana particles. Although aiming at a discovery, in the case of insufficient sensitivity the LUCIFER technique will be the demonstrator for a higher mass experiment able to probe the entire inverted hierarchy region of the neutrino mass. In order to achieve this challenging result, high resolution detectors with active background discrimination capability are required. This very interesting possibility can be largely fulfilled by scintillating bolometers thanks to the simultaneous read-out of heat and light emitted by the interactions in the detector or by pulse shape analysis.

  18. Mass and Double-Beta-Decay Q Value of {sup 136}Xe

    SciTech Connect

    Redshaw, Matthew; Wingfield, Elizabeth; McDaniel, Joseph; Myers, Edmund G.

    2007-02-02

    The atomic mass of {sup 136}Xe has been measured by comparing cyclotron frequencies of single ions in a Penning trap. The result, with 1 standard deviation uncertainty, is M({sup 136}Xe)=135.907 214 484 (11) u. Combined with previous results for the mass of {sup 136}Ba [Audi, Wapstra, and Thibault, Nucl. Phys. A 729, 337 (2003)], this gives a Q value (M[{sup 136}Xe]-M[{sup 136}Ba])c{sup 2}=2457.83(37) keV, sufficiently precise for ongoing searches for the neutrinoless double-beta decay of {sup 136}Xe.

  19. Mass and Double-Beta-Decay Q Value of Xe136

    NASA Astrophysics Data System (ADS)

    Redshaw, Matthew; Wingfield, Elizabeth; McDaniel, Joseph; Myers, Edmund G.

    2007-02-01

    The atomic mass of Xe136 has been measured by comparing cyclotron frequencies of single ions in a Penning trap. The result, with 1 standard deviation uncertainty, is M(Xe136)=135.907 214 484 (11) u. Combined with previous results for the mass of Ba136 [Audi, Wapstra, and Thibault, Nucl. Phys. A 729, 337 (2003)NUPABL0375-947410.1016/j.nuclphysa.2003.11.003], this gives a Q value (M[Xe136]-M[Ba136])c2=2457.83(37)keV, sufficiently precise for ongoing searches for the neutrinoless double-beta decay of Xe136.

  20. Nuclear-structure aspects of double beta decay

    SciTech Connect

    Suhonen, Jouni

    2010-11-24

    Neutrinoless double beta (0{nu}{beta}{beta}) decay of nuclei is a process that requires the neutrino to be a massive Majorana particle and thus cannot proceed in the standard model of electro-weak interactions. Recent results of the neutrino-oscillation experiments have produced accurate information on the mixing of neutrinos and their squared mass differences. The 0{nu}{beta}{beta} decay takes place in atomic nuclei where it can be observed, at least in principle, by underground neutrino experiments. The need of nuclei in observation of the 0{nu}{beta}{beta} decay bears two facets: The nucleus serves as laboratory for detection but at the same time its complicated many-nucleon structure interferes strongly with the analysis of the experimental data. The information about the weak-interaction observables, like the neutrino mass, has to be filtered from the data through the nuclear matrix elements (NMEs). Hence, exact knowledge about the NMEs is of paramount importance in the analysis of the data provided by the expensive and time-consuming underground experiments.

  1. 2νββ decay of 76Ge into excited states with GERDA phase I

    NASA Astrophysics Data System (ADS)

    GERDA Collaboration; Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Mi, Y.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schneider, B.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Schütz, A.-K.; Selivanenko, O.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2015-11-01

    Two neutrino double beta decay of {}76{Ge} to excited states of {}76{Se} has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in {}76{Ge} was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation γ ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90% C.L. bounds for three transitions: {0}{{g}.{{s}}.}+-{2}1+: {T}1/22ν \\gt 1.6× {10}23 yr, {0}{{g}.{{s}}.}+-{0}1+: {T}1/22ν \\gt 3.7× {10}23 yr and {0}{{g}.{{s}}.}+-{2}2+: {T}1/22ν \\gt 2.3× {10}23 yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90% credibility bounds were extracted and used to exclude several models for the {0}{{g}.{{s}}.}+-{0}1+ transition.

  2. Double-beta decay investigation with highly pure enriched ^{82}Se for the LUCIFER experiment

    NASA Astrophysics Data System (ADS)

    Beeman, J. W.; Bellini, F.; Benetti, P.; Cardani, L.; Casali, N.; Chiesa, D.; Clemenza, M.; Dafinei, I.; Domizio, S. Di; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Laubenstein, M.; Maino, M.; Nagorny, S.; Nisi, S.; Nones, C.; Orio, F.; Pagnanini, L.; Pattavina, L.; Pessina, G.; Piperno, G.; Pirro, S.; Previtali, E.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.

    2015-12-01

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of ^{82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched ^{82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched ^{82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of ^{232}Th, ^{238}U and ^{235}U are respectively: <61, <110 and <74 μ Bq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the ^{82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of ^{82}Se to 0^+_1, 2^+_2 and 2^+_1 excited states of ^{82}Kr of 3.4\\cdot 10^{22}, 1.3\\cdot 10^{22} and 1.0\\cdot 10^{22} y, respectively, with a 90 % C.L.

  3. First results on double {beta}-decay modes of Cd, Te, and Zn Isotopes

    SciTech Connect

    Bloxham, T.; Freer, M.; Boston, A.; Nolan, P.; Dawson, J.; Reeve, C.; Wilson, J. R.; Zuber, K.; Dobos, D.; Goessling, C.; Kiel, H.; Muenstermann, D.; Oehl, S.; Fox, S. P.; Fulton, B. R.; McGrath, J.; Wadsworth, R.; Harrison, P. F.; Morgan, B.; Ramachers, Y.

    2007-08-15

    Four 1-cm{sup 3} CdZnTe semiconductor detectors were operated in the Gran Sasso National Laboratory to explore the feasibility of such devices for double {beta}-decay searches as proposed for the COBRA experiment. The research involved background studies accompanied by measurements of energy resolution performed at the surface. Energy resolutions sufficient to reduce the contribution of two-neutrino double {beta}-decay events to a negligible level for a large-scale experiment have already been achieved and further improvements are expected. Using activity measurements of contaminants in all construction materials a background model was developed with the help of Monte Carlo simulations and major background sources were identified. A total exposure of 4.34 kg{center_dot}days of underground data have been accumulated allowing a search for neutrinoless double {beta}-decay modes of seven isotopes found in CdZnTe. Half-life limits (90% C.L.) are presented for decays to ground and excited states. Four improved lower limits have been obtained, including zero neutrino double electron capture transitions of {sup 64}Zn and {sup 120}Te to the ground state, which are 1.19x10{sup 17} years and 2.68x10{sup 15} years, respectively.

  4. Status of the double beta experiment COBRA

    NASA Astrophysics Data System (ADS)

    Zuber, K.

    2006-07-01

    The COBRA experiment is going to use a large number of CdZnTe semiconductor detectors to perform a search for various double beta decay modes. The current status of the experiment is presented, as well as first results. A half-life measurement of the fourfold forbidden non-unique beta-decay of 113Cd has been performed. Improved half-life limits for the ground state transitions of 64Zn for 0νβ+/EC and 0νEC/EC have been obtained. A short outlook on future activities is given.

  5. The high sensitivity double beta spectrometer TGV

    NASA Astrophysics Data System (ADS)

    Briancon, Ch.; Brudanin, V. B.; Egorov, V. G.; Janout, Z.; Koníček, J.; Kovalík, A.; Kovalenko, V. E.; Kubašta, J.; Pospíšil, S.; Revenko, A. V.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Štekl, I.; Timkin, V. V.; Tsupko-Sitnikov, V. V.; Vorobel, V.; Vylov, Ts.

    1996-02-01

    A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 × 6 mm 3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2νββ, 0νββ, 2νEC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided.

  6. Two-Neutrino Double-Beta Decay.

    NASA Astrophysics Data System (ADS)

    Guerard Ortego, Carlos-Kjell

    1992-01-01

    Two previous independent reports of 2 nubetabeta-decay by the ITEP-YPI collaboration, rm T_sp{1/2} {2nu}=(9+/- 1) times 10^ {20} yr (1sigma), and PNL-USC group, rm T_sp{1/2 }{2nu}=(1.12_sp{-0.26} {+0.48}) times 10^{21} yr (2sigma), were confirmed using a 0.25 Kg Ge(Li) detector isotopically enriched to 86% in ^{76}Ge. The detector was operated in the PNL-USC ultralow background facility in the Homestake gold mine for 168 days. Following a single correction to the data, a spectrum resembling that of the earlier PNL-USC experiment, with about the same intensity per ^{76}Ge atom, per year, was observed with a measured half life of rm T_sp{1/2}{2nu}=(9.2 _sp{-0.4}{+0.7} times 10 ^{20} y (2sigma). This experiment is one of two presented in this dissertation as original work. The half-life of the 2nubeta beta-decay of ^{100} Mo to the 1130 keV level of ^{100 }Ru has been measured to be rm T_{1/2}=(1.1_sp{-0.2} {+0.3}) times 10^{21} y (90% C.L.), by observing the 590.76 and 539.53 keV gamma rays emitted in the 0_sp{1}{+ }to 2^+to 0^+ de -excitation cascade. A review of the most relevant nuclear structure calculations is given, and their predictions are compared to the measurements from our two experiments.

  7. Sense and sensitivity of double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Gómez-Cadenas, J. J.; Martín-Albo, J.; Sorel, M.; Ferrario, P.; Monrabal, F.; Muñoz, J.; Novella, P.; Poves, A.

    2011-06-01

    The search for neutrinoless double beta decay is a very active field in which the number of proposals for next-generation experiments has proliferated. In this paper we attempt to address both the sense and the sensitivity of such proposals. Sensitivity comes first, by means of proposing a simple and unambiguous statistical recipe to derive the sensitivity to a putative Majorana neutrino mass, mββ. In order to make sense of how the different experimental approaches compare, we apply this recipe to a selection of proposals, comparing the resulting sensitivities. We also propose a ``physics-motivated range'' (PMR) of the nuclear matrix elements as a unifying criterium between the different nuclear models. The expected performance of the proposals is parametrized in terms of only four numbers: energy resolution, background rate (per unit time, isotope mass and energy), detection efficiency, and ββ isotope mass. For each proposal, both a reference and an optimistic scenario for the experimental performance are studied. In the reference scenario we find that all the proposals will be able to partially explore the degenerate spectrum, without fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO) will approach the 50 meV boundary. In the optimistic scenario, we find that CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a significant fraction of the inverse hierarchy, with NEXT covering it almost fully. For the long term future, we argue that 136Xe-based experiments may provide the best case for a 1-ton scale experiment, given the potentially very low backgrounds achievable and the expected scalability to large isotope masses.

  8. Sense and sensitivity of double beta decay experiments

    SciTech Connect

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Sorel, M.; Ferrario, P.; Monrabal, F.; Muñoz, J.; Novella, P.; Poves, A. E-mail: justo.martin-albo@ific.uv.es E-mail: paola.ferrario@ific.uv.es E-mail: jmunoz@ific.uv.es E-mail: alfredo.poves@uam.es

    2011-06-01

    The search for neutrinoless double beta decay is a very active field in which the number of proposals for next-generation experiments has proliferated. In this paper we attempt to address both the sense and the sensitivity of such proposals. Sensitivity comes first, by means of proposing a simple and unambiguous statistical recipe to derive the sensitivity to a putative Majorana neutrino mass, m{sub ββ}. In order to make sense of how the different experimental approaches compare, we apply this recipe to a selection of proposals, comparing the resulting sensitivities. We also propose a ''physics-motivated range'' (PMR) of the nuclear matrix elements as a unifying criterium between the different nuclear models. The expected performance of the proposals is parametrized in terms of only four numbers: energy resolution, background rate (per unit time, isotope mass and energy), detection efficiency, and ββ isotope mass. For each proposal, both a reference and an optimistic scenario for the experimental performance are studied. In the reference scenario we find that all the proposals will be able to partially explore the degenerate spectrum, without fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO) will approach the 50 meV boundary. In the optimistic scenario, we find that CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a significant fraction of the inverse hierarchy, with NEXT covering it almost fully. For the long term future, we argue that {sup 136}Xe-based experiments may provide the best case for a 1-ton scale experiment, given the potentially very low backgrounds achievable and the expected scalability to large isotope masses.

  9. Pattern recognition techniques to reduce backgrounds in the search for the {sup 136}Xe double beta decay with gaseous TPCs

    SciTech Connect

    Iguaz, F. J.; Cebrián, S.; Dafni, T.; Gómez, H.; Herrera, D. C.; Irastorza, I. G.; Luzon, G.; Segui, L.; Tomas, A.

    2013-08-08

    The observation of the neutrinoless double beta decay may provide essential information on the nature of neutrinos. Among the current experimental approaches, a high pressure gaseous TPC is an attractive option for the search of double beta decay due to its good energy resolution and the detailed topological information of each event. We present in this talk a detailed study of the ionization topology of the {sup 136}Xe double beta decay events in a High Pressure Xenon TPC, as well as that of the typical competing backgrounds. We define some observables based on graph theory concepts to develop automated discrimination algorithms. Our criteria are able to reduce the background level by about three orders of magnitude in the region of interest of the {sup 136}Xe Q{sub ββ} for a signal acceptance of 40%. This result provides a quantitative assessment of the benefit of topological information offered by gaseous TPCs for double beta decay search, and proves that it is a promising feature in view of future experiments in the field. Possible ideas for further improvement in the discrimination algorithms and the dependency of these results with the gas diffusion and readout granularity will be also discussed.

  10. Testing Left-Right extensions of the standard model of electroweak interactions with double-beta decay and LHC measurements

    NASA Astrophysics Data System (ADS)

    Civitarese, O.; Suhonen, J.; Zuber, K.

    2015-07-01

    The minimal extension of the standard model of electroweak interactions allows for massive neutrinos, a massive right-handed boson WR, and a left-right mixing angle ζ. While an estimate of the light (electron) neutrino can be extracted from the non-observation of the neutrinoless double beta decay, the limits on the mixing angle and the mass of the righthanded (RH) boson may be extracted from a combined analysis of the double beta decay measurements (GERDA, EXO-200 and KamLAND-Zen collaborations) and ATLAS data on the two-jets two-leptons signals following the excitation of a virtual RH boson mediated by a heavy-mass neutrino. In this work we shall compare results of both types of experiments, and show that the estimates are not in tension.

  11. Towards a Precise Energy Calibration of the CUORE Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Dally, Adam G.

    The mass of the neutrino may hold the key to many problems in cosmology and astrophysics. The observation of neutrino oscillations shows that neutrinos have mass, which was something that was not accounted for in the Standard Model of particle physics. This thesis covers topics relating to measuring the value of neutrino mass directly using bolometers. The first section will discuss the neutrino mass and different experiments for measuring the mass using bolometers. The mass of the neutrino can be measured directly from beta-decay or inferred from observation of neutrinoless double beta decay (0nubetabeta). In this work I present Monte Carlo and analytic simulation of the MARE experiment including, pile-up and energy resolution effects. The mass measurement limits of a micro-calorimeter experiments as it relates to the quantity of decays measured is provided. A similar simulation is preformed for the HolMES experiment. The motivation is to determine the sensitivity of such experiments and the detector requirements to reach the goal sensitivity. Another possible method for determining the neutrino mass is to use neutrinoless double beta decay. The second section will cover the Cryogenic Underground Observatory for Rare Events (CUORE) detector calibration system (DCS). CUORE is a neutrinoless double beta decay (0nubetabeta) experiment with an active mass of 206 kg of 130Te. The detector consists of 988 TeO2 bolometers operating at 10 mK. The signature of 0 nubetabeta decay is an excess of events at the Q-value of 2528 keV. Understanding the energy response is critical for event identification, but this presents many challenges. Calibration is necessary to associate a known energy from a gamma with a voltage pulse from the detector. The DCS must overcome many design challenges. The calibration source must be placed safely and reliable within the detector. The temperature of the detector region of the cryostat must not be changed during calibration. To achieve this

  12. Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment

    NASA Astrophysics Data System (ADS)

    Schwenke, M.; Zuber, K.; Janutta, B.; He, Z.; Zeng, F.; Anton, G.; Michel, T.; Durst, J.; Lück, F.; Gleixner, T.; Gössling, C.; Schulz, O.; Köttig, T.; Krawczynski, H.; Martin, J.; Stekl, I.; Cermak, P.

    2011-09-01

    The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.

  13. An experimental investigation of double beta decay of /sup 100/Mo

    SciTech Connect

    Dougherty, B.L.

    1988-11-17

    New limits on half-lives for several double beta decay modes of /sup 100/Mo were obtained with a novel experimental system which included thin source films interleaved with a coaxial array of windowless silicon detectors. Segmentation and timing information allowed backgrounds originating in the films to be studied in some detail. Dummy films containing /sup 96/Mo were used to assess remaining backgrounds. With 0.1 mole years of /sup 100/Mo data collected, the lower half-life limits at 90% confidence were 2.7 /times/ 10/sup 18/ years for decay via the two-neutrino mode, 5.2 /times/10/sup 19/ years for decay with the emission of a Majoron, and 1.6 /times/ 10/sup 20/ years and 2.2 /times/ 10/sup 21/ years for neutrinoless 0/sup +/ ..-->.. 2/sup +/ and 0/sup +/ ..-->.. 0/sup +/ transitions, respectively. 50 refs., 38 figs., 11 tabs.

  14. First array of enriched Zn^{82}Se bolometers to search for double beta decay

    NASA Astrophysics Data System (ADS)

    Artusa, D. R.; Balzoni, A.; Beeman, J. W.; Bellini, F.; Biassoni, M.; Brofferio, C.; Camacho, A.; Capelli, S.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Clemenza, M.; Cremonesi, O.; Cruciani, A.; D'Addabbo, A.; Dafinei, I.; Di Domizio, S.; di Vacri, M. L.; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Keppel, G.; Maino, M.; Mancuso, M.; Martinez, M.; Morganti, S.; Nagorny, S.; Nastasi, M.; Nisi, S.; Nones, C.; Orio, F.; Orlandi, D.; Pagnanini, L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Pirro, S.; Pozzi, S.; Previtali, E.; Puiu, A.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.; Zolotarova, A.

    2016-07-01

    The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in ^{82}Se, the Zn^{82}Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn^{82}Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

  15. Capturing relic neutrinos with {beta}- and double {beta}-decaying nuclei

    SciTech Connect

    Hodak, Rastislav; Kovalenko, Sergey; Simkovic, Fedor

    2009-11-09

    Neutrinos are probably one of the most important structural constituents of the Universe. The Big Bang Theory predicts that the significant component of them is formed by the cosmic neutrino background, an analogues of the big bang relic photons comprising the cosmic microwave background radiation, which has been measured with amazing accuracy. Properties of the relic neutrino background are closely related to the ones of the cosmic microwave radiation. Relic neutrinos pervade space, but their temperature is extremely small, being of the order of 0.1 meV. Although belonging to the most abundant particles of the Universe, the relic neutrinos evade direct detection so far. This is because the low-energy neutrinos interact only very weakly with matter. In this contribution, we explore the feasibility to detect the cosmic neutrino background by means of {beta}-decaying ({sup 3}H and {sup 187}Re) and double beta decaying ({sup 100}Mo) nuclei. In addition, we address the question whether double relic neutrino capture on nuclei can be an obstacle for observation of neutrinoless double {beta}-decay.

  16. Radiopure ZnMoO4 scintillating bolometers for the LUMINEU double-beta experiment

    NASA Astrophysics Data System (ADS)

    Poda, D. V.; Armengaud, E.; Arnaud, Q.; Augier, C.; Barabash, A. S.; Benoît, A.; Benoît, A.; Bergé, L.; Boiko, R. S.; Bergmann, T.; Blümer, J.; Broniatowski, A.; Brudanin, V.; Camus, P.; Cazes, A.; Censier, B.; Chapellier, M.; Charlieux, F.; Chernyak, D. M.; Coron, N.; Coulter, P.; Cox, G. A.; Danevich, F. A.; de Boissière, T.; Decourt, R.; De Jesus, M.; Devoyon, L.; Drillien, A.-A.; Dumoulin, L.; Eitel, K.; Enss, C.; Filosofov, D.; Fleischmann, A.; Fourches, N.; Gascon, J.; Gastaldo, L.; Gerbier, G.; Giuliani, A.; Gros, M.; Hehn, L.; Henry, S.; Hervé, S.; Heuermann, G.; Humbert, V.; Ivanov, I. M.; Juillard, A.; Kéfélian, C.; Kleifges, M.; Kluck, H.; Kobychev, V. V.; Koskas, F.; Kozlov, V.; Kraus, H.; Kudryavtsev, V. A.; Le Sueur, H.; Loidl, M.; Magnier, P.; Makarov, E. P.; Mancuso, M.; de Marcillac, P.; Marnieros, S.; Marrache-Kikuchi, C.; Menshikov, A.; Nasonov, S. G.; Navick, X.-F.; Nones, C.; Olivieri, E.; Pari, P.; Paul, B.; Penichot, Y.; Pessina, G.; Piro, M. C.; Plantevin, O.; Redon, T.; Robinson, M.; Rodrigues, M.; Rozov, S.; Sanglard, V.; Schmidt, B.; Shlegel, V. N.; Siebenborn, B.; Strazzer, O.; Tcherniakhovski, D.; Tenconi, M.; Torres, L.; Tretyak, V. I.; Vagneron, L.; Vasiliev, Ya. V.; Velazquez, M.; Viraphong, O.; Walker, R. J.; Weber, M.; Yakushev, E.; Zhang, X.; Zhdankov, V. N.

    2015-08-01

    The results of R&D of radiopure zinc molybdate (ZnMoO4) based scintillating bolometers for the LUMINEU (Luminescent Underground Molybdenum Investigation for NEUtrino mass and nature) double-beta decay experiment are presented. A dedicated two-stage molybdenum purification technique (sublimation in vacuum and recrystallization from aqueous solutions) and an advanced directional solidification method (the low-thermal-gradient Czochralski technique) were utilized to produce high optical quality large mass (˜1 kg) ZnMoO4 crystal boules and first 100Mo (99.5%) enriched Zn100MoO4 crystal scintillator (mass of ˜0.2 kg). Scintillating bolometers based on ZnMoO4 (≈ 0.33 kg) and Zn100MoO4 (≈ 0.06 kg) scintillation elements and high purity Ge wafers were tested in the EDELWEISS set-up at the Modane Underground Laboratory (France). Long term low temperature tests demonstrate excellent detectors' performance and effectiveness of the purification and solidification procedures for the achievement of high radiopurity of the material, in particular with a bulk activity of 228Th and 226Ra below 4 µBq/kg. The adopted protocol was used to produce for the first time a large volume Zn100MoO4 crystal scintillator (mass of ˜1.4 kg, 100Mo enrichment is 99.5%) to search for neutrinoless double-beta decay of 100Mo in the framework of the LUMINEU project.

  17. Status and future prospect of 48Ca double beta decay search in CANDLES

    NASA Astrophysics Data System (ADS)

    Iida, T.; Nakajima, K.; Ajimura, S.; Batpurev, T.; Chan, W. M.; Fushimi, K.; Hazama, R.; Kakubata, H.; Khai, B. T.; Kishimoto, T.; Li, X.; Maeda, T.; Masuda, A.; Matsuoka, K.; Morishita, K.; Nakatani, N.; Nomachi, M.; Noshiro, S.; Ogawa, I.; Ohata, T.; Osumi, H.; Suzuki, K.; Tamagawa, Y.; Tesuno, K.; Trang, V. T. T.; Uehara, T.; Umehara, S.; Yoshida, S.

    2016-05-01

    The observation of neutrino-less double beta decay (0vßß) would be the most practical way to prove the Majorana nature of the neutrino and lepton number violation. CANDLES studies 48Ca double beta decay using CaF2 scintillator. The main advantage of 48Ca is that it has the highest Q-value (4.27 MeV) among all the isotope candidates for 0vßß. The CANDLES III detector is currently operating with 300kg CaF2 crystals in the Kamioka underground observatory, Japan. In 2014, a detector cooling system and a magnetic cancellation coil was installed with the aim to increase light emission of CaF2 scintillator and photo-electron collection efficiency of the photo-multipliers. After this upgrade, light yield was increased to 1000 p.e./MeV which is 1.6 times larger than before. According to data analysis and simulation, main background source in CANDLES is turned out to be high energy external gamma-ray originating neutron capture on the surrounding materials, so called (n,γ). Upgrading the detector by installing neutron and gamma-ray shield can reduce the remaining main backgrounds by two order magnitude. In this report, we discuss the detail of (n,γ) and background reduction by additional shielding.

  18. Bonner Prize Talk -- First Laboratory Observation of Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Moe, Michael

    2013-04-01

    Although we are awash in neutrinos, we remain ignorant of some of their fundamental properties. We don't know their masses. We don't know whether ``anti-neutrinos'' are really distinct particles. Double beta (ββ) decay offers a handle on these questions if we can observe the energy spectrum of the two emitted electrons, and determine whether or not they share their energy with two neutrinos. Seeing neutrinoless (0ν) decay would solve some enduring puzzles. The power of the process to elucidate the neutrino was recognized in the 1930's, but ββ decay would be exceedingly rare and difficult to detect. Unsuccessful laboratory searches had been going on for 25 years when the UC Irvine group began its first experiment with a cloud chamber in 1972. After some background for the non-expert, and a snapshot of the theoretical and experimental milieu at the time, the talk will begin with the reasons for choosing a cloud chamber, and the taming of its balky and idiosyncratic behavior. The talk will end with the first definitive observation of two-neutrino (2ν)ββ decay of ^82Se in the vastly superior time projection chamber (TPC) in 1987. Discouragement through the tortuous 15-year interval was relieved by occasional victories. Some I will illustrate with revealing cloud-chamber photographs. We learned many things from this primitive device, and after seven years we isolated an apparent ββ decay signal. But the efficiency of the trigger was small, and difficult to pin down. Estimating 2.2%, we were way low. The resulting ``short'' ^82Se half-life of 1 x 10^19 years was suspect. New technology came to the rescue with the invention of the TPC. Experience with the cloud chamber guided our design of a TPC specifically for ββ decay. The TPC was built from scratch. Its long, steep learning curve was also punctuated with little triumphs. A memorable moment was the first turn-on of a portion of the chamber. So long ago, this all seems rather quaint, but through ample use of

  19. No-neutrino double beta decay: more than one neutrino

    SciTech Connect

    Rosen, S.P.

    1983-01-01

    Interference effects between light and heavy Majorana neutrinos in the amplitude for no-neutrino double beta decay are discussed. The effects include an upper bound on the heavy neutrino mass, and an A dependence for the effective mass extracted from double beta decay. Thus the search for the no-neutrino decay mode should be pursued in several nuclei, and particularly in Ca/sup 48/, where the effective mass may be quite large.

  20. Solving the Neutrino Mass Mystery using Double Beta Decay. An Examination of the Feasibility of Xennoon Purification and Ion Capture and Release using an Electrostatic Probe

    SciTech Connect

    Outschoorn, Verena M

    2003-09-05

    Double beta decay has long been recognized as a useful avenue for the study of electron neutrinos, especially the neutrino mass and its fundamental nature (Majorana or Dirac). Recent neutrino oscillation experiments have provided compelling evidence that the neutrino has mass. The detection of the neutrinoless mode of double beta decay would finally set a lower limit on the mass of the electron neutrino, as well as prove that the neutrino is a Majorana particle (with opposite spin, it is its own anti-particle). The Enriched Xenon Observatory (EXO) project attempts to detect neutrinoless double beta decay using {sup 136}Xe that decays by this process to {sup 136}Ba{sup 2} + e{sup -} + e{sup -}. Perhaps one of the most significant characteristics of this project is the reduction of the background through the identification of the Barium ions for each individual event using laser fluorescence techniques. This project also proposes to collect scintillation light in addition to the ionization electrons in order to further improve energy resolution. Current work at SLAC includes the development of a purification system for xenon, as well as tests for the capture and release of single ions using an electrostatic probe.

  1. Inelastic neutron scattering cross sections for Ge76 relevant to background in neutrinoless double- β decay experiments

    DOE PAGESBeta

    Crider, B. P.; Peters, E. E.; Allmond, J. M.; McEllistrem, M. T.; Prados-Estévez, F. M.; Ross, T. J.; Vanhoy, J. R.; Yates, S. W.

    2015-09-11

    The experimental signature in searches for the neutrinoless double- decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Moreover, inelastic scattering reactions with neutrons from muon-induced interactions and ( ,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We also measured the production cross sections for rays from the 76Ge(n,n ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the crossmore » sections of a previously known 2040.7-keV ray from the 3952-keV level in 76 Ge are rather small, we find that a larger contribution arises from a 2037.5-keV ray which is attributed to a newly identified level at 3147 keV in 76Ge. Finally, a third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double- decay searches is more complex than was previously thought.« less

  2. Radiopure ZnMoO{sub 4} scintillating bolometers for the LUMINEU double-beta experiment

    SciTech Connect

    Poda, D. V.; Chernyak, D. M.; Armengaud, E.; Boissière, T. de; Fourches, N.; Gerbier, G.; Gros, M.; Hervé, S.; Magnier, P.; Navick, X-F.; Nones, C.; Paul, B.; Penichot, Y.; Arnaud, Q.; Augier, C.; Benoît, A.; Cazes, A.; Censier, B.; Charlieux, F.; De Jesus, M. [IPNL, Université de Lyon, Université Lyon 1, CNRS and others

    2015-08-17

    The results of R&D of radiopure zinc molybdate (ZnMoO{sub 4}) based scintillating bolometers for the LUMINEU (Luminescent Underground Molybdenum Investigation for NEUtrino mass and nature) double-beta decay experiment are presented. A dedicated two-stage molybdenum purification technique (sublimation in vacuum and recrystallization from aqueous solutions) and an advanced directional solidification method (the low-thermal-gradient Czochralski technique) were utilized to produce high optical quality large mass (∼1 kg) ZnMoO{sub 4} crystal boules and first {sup 100}Mo (99.5%) enriched Zn{sup 100}MoO{sub 4} crystal scintillator (mass of ∼0.2 kg). Scintillating bolometers based on ZnMoO{sub 4} (≈ 0.33 kg) and Zn{sup 100}MoO{sub 4} (≈ 0.06 kg) scintillation elements and high purity Ge wafers were tested in the EDELWEISS set-up at the Modane Underground Laboratory (France). Long term low temperature tests demonstrate excellent detectors’ performance and effectiveness of the purification and solidification procedures for the achievement of high radiopurity of the material, in particular with a bulk activity of {sup 228}Th and {sup 226}Ra below 4 µBq/kg. The adopted protocol was used to produce for the first time a large volume Zn{sup 100}MoO{sub 4} crystal scintillator (mass of ∼1.4 kg, {sup 100}Mo enrichment is 99.5%) to search for neutrinoless double-beta decay of {sup 100}Mo in the framework of the LUMINEU project.

  3. The Status of Kamland-Zen for Neutrinoless Double Beta Decay of 136Xe

    NASA Astrophysics Data System (ADS)

    Shirai, Junpei

    2015-03-01

    KamLAND-Zen is a unique 0νββ decay experiment for 136Xe by utilizing a large volume liquid scintillator detector KamLAND. In this report the analysis results of the collected data corresponding to 89.5kg yr exposure of 136Xe, the current efforts for background reduction and the future plan are given.

  4. Can one measure nuclear matrix elements of neutrinoless double {beta} decay?

    SciTech Connect

    Rodin, Vadim; Faessler, Amand

    2009-10-15

    By making use of the isospin conservation by strong interaction, the Fermi 0{nu}{beta}{beta} nuclear matrix element M{sub F}{sup 0{nu}} is transformed to acquire the form of an energy-weighted double Fermi transition matrix element. This useful representation allows reconstruction of the total M{sub F}{sup 0{nu}} provided a small isospin-breaking Fermi matrix element between the isobaric analog state in the intermediate nucleus and the ground state of the daughter nucleus could be measured, e.g., by charge-exchange reactions. Such a measurement could set a scale for the 0{nu}{beta}{beta} nuclear matrix elements and help to discriminate between the different nuclear structure models in which calculated M{sub F}{sup 0{nu}} may differ by as much as a factor of 5 (that translates to about 20% difference in the total M{sup 0{nu}})

  5. LUCIFER: A Scintillating Bolometer Array for the Search of Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Cardani, L.; Lucifer Collaboration

    2012-07-01

    One of the main limitations in the study of 0vDBD is the presence of a radioactive background in the energy region of interest. This limit can be overcome by the technological approach of the LUCIFER project, which is based the double read-out of the heat and scintillation light produced by ZnSe scintillating bolometers. This experiment aims at a background lower than 10-3counts/keV/kg/y in the energy region of the 0νDBD of 82Se. Such a low background level will provide a sensitivity on the effective neutrino mass of the order of 100 meV. In the following, the results of the recent R&D activity are discussed, the single module for the LUCIFER detector is described, and the process for the production of 82Se-enriched ZnSe crystals is presented.

  6. Computer code for double beta decay QRPA based calculations

    SciTech Connect

    Barbero, C. A.; Mariano, A.; Krmpotić, F.; Samana, A. R.; Ferreira, V. dos Santos; Bertulani, C. A.

    2014-11-11

    The computer code developed by our group some years ago for the evaluation of nuclear matrix elements, within the QRPA and PQRPA nuclear structure models, involved in neutrino-nucleus reactions, muon capture and β{sup ±} processes, is extended to include also the nuclear double beta decay.

  7. The (d,{sup 2}He) reaction on {sup 76}Se and the double-{beta}-decay matrix elements for A=76

    SciTech Connect

    Grewe, E.-W.; Baeumer, C.; Dohmann, H.; Frekers, D.; Hollstein, S.; Rakers, S.; Thies, J. H.; Harakeh, M. N.; Berg, A. M. van den; Woertche, H. J.; Johansson, H.; Simon, H.; Popescu, L.; Savran, D.; Zilges, A.

    2008-10-15

    The (d,{sup 2}He) charge-exchange reaction on {sup 76}Se was studied at an incident energy of 183 MeV. The outgoing two protons in the {sup 1}S{sub 0} state, referred to as {sup 2}He, were both momentum analyzed and detected by the same spectrometer and detector. The experiment was performed at KVI, Groningen, using the magnetic spectrometer BBS at three angular positions: 0 deg., 2.5 deg., and 5 deg. Excitation-energy spectra of the residual nucleus {sup 76}As were obtained with an energy resolution of about 120 keV (FWHM). Gamow-Teller (GT{sup +}) transition strengths were extracted up to 5 MeV and compared with those from an (n,p) experiment at low resolution. Together with the GT{sup -} transition strengths from the {sup 76}Ge(p,n) experiment leading to the same intermediate nucleus, the nuclear matrix element of the two-neutrino double-{beta} decay of {sup 76}Ge was evaluated.

  8. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S.; Cervera, A.; Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Fernández, M.; Ferrario, P.; Freitas, E. D. C.; Fernandes, L. M. P.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Morata, J. A. Hernando; Herrera, D. C.; Irastorza, I. G.; Laing, A.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Martínez-Lema, G.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Vidal, J. Muñoz; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; de Solórzano, A. Ortiz; Aparicio, J. L. Pérez; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2015-08-01

    The "Neutrino Experiment with a Xenon TPC" (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.

  9. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    SciTech Connect

    Cebrián, S.; Dafni, T.; González-Díaz, D.; Herrera, D. C.; Irastorza, I. G.; Luzón, G.; Ortiz de Solórzano, A.; Villar, J. A.; Álvarez, V.; Cárcel, S.; Cervera, A.; Díaz, J.; Ferrario, P.; Gómez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; López-March, N. [Instituto de Física Corpuscular, CSIC & Universitat de València, C and others

    2015-08-17

    The ”Neutrino Experiment with a Xenon TPC” (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in {sup 136}Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.

  10. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S.; Cervera, A.; Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Fernández, M.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Laing, A.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Martínez-Lema, G.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Ortiz de Solórzano, A.; Pérez Aparicio, J. L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2015-05-01

    The ``Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was specially challenging since the needed components like printed circuit boards, connectors, sensors or capacitors have typically, according to available information in databases and in the literature, activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain) is described. According to the obtained results, radiopure enough printed circuit boards made of kapton and copper, silicon photomultipliers and other required components, fulfilling the requirement of an overall background level in the region of interest of at most 8×10-4 counts keV-1 kg-1 y-1, have been identified.

  11. Status of the COBRA double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Zuber, Kai

    2010-01-01

    The current status of the COBRA experiment is described. Results on the 4-fold forbidden beta decay of 113Cd and a variety of double beta decay limits of Cd, Zn and Te isotopes are presented based on 18 kg × days of exposure with an array of sixteen CdZnTe semiconductor detectors. A short description on the activities with pixelated detectors for tracking is given.

  12. The status of the COBRA double-beta-decay experiment

    NASA Astrophysics Data System (ADS)

    Zuber, K.

    2010-04-01

    The current status of the COBRA experiment is described. Results on the fourfold-forbidden beta decay of 113Cd and a variety of double-beta-decay limits for Cd, Zn and Te isotopes are presented, based on 18 kg× days of exposure with an array of sixteen CdZnTe semiconductor detectors. A short description of the activities with pixelated detectors for tracking is given.

  13. MeV neutrinos in double {beta} decay

    SciTech Connect

    Zuber, K.

    1997-08-01

    The effect of Majorana neutrinos in the MeV mass range on the double {beta} decay of various isotopes is studied on pure phenomenological arguments. By using only experimental half-life data, limits on the mixing parameter U{sub eh}{sup 2} of the order 10{sup {minus}7} can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined. {copyright} {ital 1997} {ital The American Physical Society}

  14. Status and perspectives of the COBRA double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Kiel, Henning; COBRA Collaboration

    2006-05-01

    The COBRA experiment is going to use a large amount of CdZnTe semiconductor detectors to perform a search for various double beta decay modes. The current status of the experiment is presented, as well as first results. A half-life measurement of the 4-fold forbidden non-unique beta-decay of 113Cd has been performed. Improved half-life limits for the ground state transitions of 64Zn for 0νβ+/EC and 0νEC/EC have been obtained. A short outlook on future activities is given.

  15. Values of the phase space factors for double beta decay

    SciTech Connect

    Stoica, Sabin Mirea, Mihai

    2015-10-28

    We report an up-date list of the experimentally most interesting phase space factors for double beta decay (DBD). The electron/positron wave functions are obtained by solving the Dirac equations with a Coulomb potential derived from a realistic proton density distribution in nucleus and with inclusion of the finite nuclear size (FNS) and electron screening (ES) effects. We build up new numerical routines which allow us a good control of the accuracy of calculations. We found several notable differences as compared with previous results reported in literature and possible sources of these discrepancies are discussed.

  16. Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay

    SciTech Connect

    Horoi, Mihai

    2013-12-30

    Recent progress in the shell model approach to the nuclear matrix elements for the double beta decay process are presented. This includes nuclear matrix elements for competing mechanisms to neutrionless double beta decay, a comparison between closure and non-closure approximation for {sup 48}Ca, and an updated shell model analysis of nuclear matrix elements for the double beta decay of {sup 136}Xe.

  17. Radon emanation based material measurement and selection for the SuperNEMO double beta experiment

    NASA Astrophysics Data System (ADS)

    Cerna, Cédric; Soulé, Benjamin; Perrot, Frédéric

    2015-08-01

    The SuperNEMO Demonstrator experiment aims to study the neutrinoless double beta decay of 7 kg of 82Se in order to reach a limit on the light Majorana neutrino mass mechanism T1/2 (ββ0ν) > 6.5 1024 years (90%CL) equivalent to a mass sensitivity mββ < 0.20 - 0.40 eV (90%CL) in two years of data taking. The detector construction started in 2014 and its installation in the Laboratoire Souterrain de Modane (LSM) is expected during the course of 2015. The remaining level of 226Ra (238U chain) in the detector components can lead to the emanation of 222Rn gas. This isotope should be controlled and reduced down to the level of a 150 µBq/m3 in the tracker chamber of the detector to achieve the physics goals. Besides the HPGe selection of the detector materials for their radiopurity, the most critical materials have been tested and selected in a dedicated setup facility able to measure their 222Rn emanation level. The operating principle relies on a large emanation tank (0.7m3) that allows measuring large material surfaces or large number of construction pieces. The emanation tank is coupled to an electrostatic detector equipped with a silicon diode to perform the alpha spectroscopy of the gas it contains and extract the 222Rn daughters. The transfer efficiency and the detector efficiency have been carefully calibrated through different methods. The intrinsic background of the system allows one to measure 222Rn activities down to 3 mBq, leading to a typical emanation sensitivity of 20 µBq/m2/day for a 30 m2 surface sample. Several construction materials have been measured and selected, such as nylon and aluminized Mylar films, photomultipliers and tracking of the SuperNEMO Demonstrator.

  18. A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment

    SciTech Connect

    Kogler, Laura K.

    2011-11-30

    CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2vββ). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO2 crystals arranged in a tower and operated at a temperature of 10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors. The experiment included 4 enriched crystals, 2 enriched with 130Te and 2 with 128Te, in order to aid in the measurement of the 2vββ rate. The enriched crystals contained a total of 350 g 130Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130- enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2vββ half-life was measured to be T2v1/2 = [9.81± 0.96(stat)± 0.49(syst)] x1020 y.

  19. Study of 48Ca double beta decay by CANDLES

    NASA Astrophysics Data System (ADS)

    Ogawa, I.; Kishimoto, T.; Umehara, S.; Ito, G.; Yasuda, K.; Kakubata, H.; Miyashita, M.; Takubo, K.; Matsuoka, K.; Nomachi, M.; Saka, M.; Seki, K.; Fushimi, K.; Hazama, R.; Ohsumi, H.; Okada, K.; Tamagawa, Y.; Jinno, T.; Fujiwara, N.; Yoshida, S.; CANDLES Collaboration

    2012-07-01

    CANDLES is the project to search for double beta decay (DBD) of 48Ca by using CaF2 scintillators. The Q-value of 48Ca, which is the highest (4.27 MeV) among potential DBD nuclei, is far above energies of γ-rays from natural radioactivities (maximum 2.615 MeV from 208Tl decay), therefore we can naturally expect small backgrounds in the energy region we are interested in. We have constructed the prototype detector, CANDLES III in our laboratory (Osaka U.) at sea level and studied the basic performance of the system, including the light collection, position reconstruction and background rejection. After R&D study we moved the detector system to new experimental room at Kamioka underground laboratory. Herein the expected performances and current status of the CANDLES system are described.

  20. Measurement of double-beta-decay—experiments TGV and NEMO

    NASA Astrophysics Data System (ADS)

    Štekl, I.

    2001-06-01

    A description of the aim and present status of the experiments NEMO and TGV are presented. The NEMO collaboration developed the detector NEMO-2 to investigate double-beta ( ββ) decay of 100Mo, 116Cd, 82Se and 96Zr. The results obtained for the above mentioned isotopes are given. The new detector NEMO-3, which is approximately 20 times larger than NEMO-2, is under construction. The NEMO-3 detector should allow the study of 0 νββ decays of 100Mo (or other isotopes) with half-life ˜10 25years, corresponding to neutrino masses of 0.1- 0.3 eV. The TGV I collaboration has studied the ββ decay of 48Ca. The result T 2 νββ1/2=(4.2 +3.3-1.3)×10 19 years has been found. Experiment TGV II is devoted to measurement of the ββ decay (β +β +, β +/ EC, EC/ EC) of 106Cd, particularly the 2 νEC/EC mode.

  1. Purification of lanthanides for double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Tretyak, V. I.

    2013-08-01

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain 238U, 226Ra and 232,228Th typically on the level of ˜ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO2, Nd2O3 and Gd2O3. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R&D of the methods to remove the pollutions with improved efficiency is in progress.

  2. Purification of lanthanides for double beta decay experiments

    SciTech Connect

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Danevich, F. A.; Mokina, V. M.; Poda, D. V.; Tretyak, V. I.; Cappella, F.; Incicchitti, A.; Cerulli, R.; Laubenstein, M.; Nisi, S.

    2013-08-08

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ∼ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.

  3. Results on Neutrinoless Double-β Decay of Ge76 from Phase I of the GERDA Experiment

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2013-09-01

    Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the standard model of particle physics. This Letter reports the results from phase I of the Germanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory (Italy) searching for neutrinoless double beta decay of the isotope Ge76. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1×10-2counts/(keVkgyr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of Ge76, T1/20ν>2.1×1025yr (90% C.L.). The combination with the results from the previous experiments with Ge76 yields T1/20ν>3.0×1025yr (90% C.L.).

  4. Radon emanation based material measurement and selection for the SuperNEMO double beta experiment

    SciTech Connect

    Cerna, Cédric Soulé, Benjamin; Perrot, Frédéric

    2015-08-17

    The SuperNEMO Demonstrator experiment aims to study the neutrinoless double beta decay of 7 kg of {sup 82}Se in order to reach a limit on the light Majorana neutrino mass mechanism T{sub 1/2} (ββ0ν) > 6.5 10{sup 24} years (90%CL) equivalent to a mass sensitivity mβ{sub β} < 0.20 - 0.40 eV (90%CL) in two years of data taking. The detector construction started in 2014 and its installation in the Laboratoire Souterrain de Modane (LSM) is expected during the course of 2015. The remaining level of {sup 226}Ra ({sup 238}U chain) in the detector components can lead to the emanation of {sup 222}Rn gas. This isotope should be controlled and reduced down to the level of a 150 µBq/m{sup 3} in the tracker chamber of the detector to achieve the physics goals. Besides the HPGe selection of the detector materials for their radiopurity, the most critical materials have been tested and selected in a dedicated setup facility able to measure their {sup 222}Rn emanation level. The operating principle relies on a large emanation tank (0.7m{sup 3}) that allows measuring large material surfaces or large number of construction pieces. The emanation tank is coupled to an electrostatic detector equipped with a silicon diode to perform the alpha spectroscopy of the gas it contains and extract the {sup 222}Rn daughters. The transfer efficiency and the detector efficiency have been carefully calibrated through different methods. The intrinsic background of the system allows one to measure 222Rn activities down to 3 mBq, leading to a typical emanation sensitivity of 20 µBq/m{sup 2}/day for a 30 m{sup 2} surface sample. Several construction materials have been measured and selected, such as nylon and aluminized Mylar films, photomultipliers and tracking of the SuperNEMO Demonstrator.

  5. Evaluation of radioactive background rejection in 76Ge neutrino-lessdouble-beta decay experiments using a highly segmented HPGe detector

    SciTech Connect

    Chan, Yuen-Dat; Campbell, D.B.; Vetter, K.; Henning, R.; Lesko, K.; Chan, Y.D.; Poon, A.W.P.; Perry, M.; Hurley, D.; Smith, A.R.

    2007-02-05

    A highly segmented coaxial HPGe detector was operated in a low background counting facility for over 1 year to experimentally evaluate possible segmentation strategies for the proposed Majorana neutrino-less double-beta decay experiment. Segmentation schemes were evaluated on their ability to reject multi-segment events while retaining single-segment events. To quantify a segmentation scheme's acceptance efficiency the percentage of peak area due to single segment events was calculated for peaks located in the energy region 911-2614 keV. Single interaction site events were represented by the double-escape peak from the 2614 keV decay in {sup 208}Tl located at 1592 keV. In spite of its prototypical nature, the detector performed well under realistic operating conditions and required only minimal human interaction. Though the energy resolution for events with interactions in multiple segments was impacted by inter-segment cross-talk, the implementation of a cross-talk correlation matrix restored acceptable resolution. Additionally, simulations utilizing the MaGe simulation package were performed and found to be in good agreement with experimental observations verifying the external nature of the background radiation.

  6. Influence of Pairing on the Nuclear Matrix Elements of the Neutrinoless {beta}{beta} Decays

    SciTech Connect

    Caurier, E.; Nowacki, F.

    2008-02-08

    We study in this Letter the neutrinoless double beta decay nuclear matrix elements (NME's) in the framework of the interacting shell model. We analyze them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME's predicted by different nuclear models. In addition, it gives back the protagonist role in this process to the pairing interaction, the one which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, comparable to those implicit in the quasiparticle RPA in a spherical basis, tend to overestimate the NME's in several decays.

  7. Influence of Pairing on the Nuclear Matrix Elements of the Neutrinoless ββ Decays

    NASA Astrophysics Data System (ADS)

    Caurier, E.; Menéndez, J.; Nowacki, F.; Poves, A.

    2008-02-01

    We study in this Letter the neutrinoless double beta decay nuclear matrix elements (NME’s) in the framework of the interacting shell model. We analyze them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME’s predicted by different nuclear models. In addition, it gives back the protagonist role in this process to the pairing interaction, the one which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, comparable to those implicit in the quasiparticle RPA in a spherical basis, tend to overestimate the NME’s in several decays.

  8. Improving the physics impact of next-generation 76Ge neutrinoless double-beta decay experiments

    SciTech Connect

    Hossbach, Todd W.

    2009-01-01

    It was shown that segmentation and pulse-shape discrimination can improve the discovery sensitivity of a next-gen 0vBB-decay experiment by 90%. - However, when practical aspects are considered (such as instrumenting each segment with front-end electronics), the discovery sensitivity is decreased by 19%. - This has extremely important consequences to proposed next-gen experiments since the two active collaborations have strongly advocated the use of segmented detectors for all or part of the experiment. - New germanium detector technology, currently under development, has demonstrated excellent multi-site background rejection capabilities without the complexity of segmentation or complicated PSD algorithms. - The physically-segmented p-type germanium detector technology has proven to be a useful and practical tool in modern nuclear physics. The PSEG technology deserves further development as it has the potential for use in a variety of applications.

  9. Final Technical Report [Cosmogenic background and shielding R&D for a Ge Neutrinoless Double Beta Decay Experiment

    SciTech Connect

    Guiseppe, Vince

    2013-10-01

    The USD Majorana group focused all of its effort in support of the MAJORANA DEMONSTRATOR (MJD) experiment. Final designs of the shielding subsystems are complete. Construction of the MJD shielding systems at SURF has begun and the proposed activities directly support the completion of the shield systems. The PI and the group contribute heavily to the onsite construction activities of the MJD experiment. The group led investigations into neutron and neutron-­induced backgrounds, shielding effectiveness and design, and radon backgrounds.

  10. Experiments TGV I (double-beta decay of 48Ca) and TGV II (double-beta decay of 106Cd and 48Ca)

    NASA Astrophysics Data System (ADS)

    Štekl, I.; Čermák, P.; Beneš, P.; Brudanin, V. B.; Rukhadze, N. I.; Egorov, V. G.; Kovalenko, V. E.; Kovalík, A.; Salamatin, A. V.; Tsoupko-Sitnikov, V. V.; Vylov, Ts.; Briancon, Ch.; Šimkovic, F.

    2000-04-01

    Present status of experiments TGV I and TGV II is given. The TGV I collaboration has studied the double-beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer TGV (Telescope Germanium Vertical). The preliminary results of years and years (90% CL) for double-beta decay of 48 Ca has been found after the processing of experimental data obtained after 8700 hours of measuring time using approximately 1 gramme of 48Ca. The aim of the experiment TGV II is the development of the experimental methods, construction of spectrometers and measurement of the decay (++, β+/EC, EC/EC) of 106Cd particularly the 2νEC/EC mode. The theoretical description and performance of the TGV II spectrometer are also given.

  11. Experimental study of double-{beta} decay modes using a CdZnTe detector array

    SciTech Connect

    Dawson, J. V.; Goessling, C.; Koettig, T.; Muenstermann, D.; Rajek, S.; Schulz, O.; Janutta, B.; Zuber, K.; Junker, M.; Reeve, C.; Wilson, J. R.

    2009-08-15

    An array of sixteen 1 cm{sup 3} CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double-{beta} decay searches with such devices. As one of the double-{beta} decay experiments with the highest granularity the 4x4 array accumulated an overall exposure of 18 kg days. The setup and performance of the array is described. Half-life limits for various double-{beta} decay modes of Cd, Zn, and Te isotopes are obtained. No signal has been found, but several limits beyond 10{sup 20} years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation. An improved limit for the {beta}{sup +}/EC decay of {sup 120}Te is given.

  12. γ production and neutron inelastic scattering cross sections for 76Ge

    NASA Astrophysics Data System (ADS)

    Rouki, C.; Domula, A. R.; Drohé, J. C.; Koning, A. J.; Plompen, A. J. M.; Zuber, K.

    2013-11-01

    The 2040.7-keV γ ray from the 69th excited state of 76Ge was investigated in the interest of Ge-based double-β-decay experiments like the Germanium Detector Array (GERDA) experiment. The predicted transition could interfere with valid 0νββ events at 2039.0 keV, creating false signals in large-volume 76Ge enriched detectors. The measurement was performed with the Gamma Array for Inelastic Neutron Scattering (GAINS) at the Geel Electron Linear Accelerator (GELINA) white neutron source, using the (n,n'γ) technique and focusing on the strongest γ rays originating from the level. Upper limits obtained for the production cross section of the 2040.7-keV γ ray showed no possible influence on GERDA data. Additional analysis of the data yielded high-resolution cross sections for the low-lying states of 76Ge and related γ rays, improving the accuracy and extending existing data for five transitions and five levels. The inelastic scattering cross section for 76Ge was determined for incident neutron energies up to 2.23 MeV, significantly increasing the energy range for which experimental data are available. Comparisons with model calculations using the talys code are presented indicating that accounting for the recently established asymmetric rotor structure should lead to an improved description of the data.

  13. Search for double beta decay of 48Ca in the TGV experiment

    NASA Astrophysics Data System (ADS)

    Brudanin, V. B.; Rukhadze, N. I.; Briançon, C.; Egorov, V. G.; Kovalenko, V. E.; Kovalik, A.; Salamatin, A. V.; Štekl, I.; Tsoupko-Sitnikov, V. V.; Vylov, T.; Čermák, P.

    2000-12-01

    This Letter describes a collaborative TGV (Telescope Germanium Vertical) study of the double beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer. The results of T1/22νββ=(4.2+3.3- 1.3)×1019 years and T1/20νββ>1.5×1021 years (90% CL) for double beta decay of 48Ca were found after processing experimental data obtained after 8700 hours of measuring time, using approximately 1 gramme of 48Ca. The features of a TGV-2 experiment are also presented.

  14. The MAJORANA Experiment

    SciTech Connect

    Guiseppe, V.E.; Keller, C.; Mei, D-M; Perevozchikov, O.; Perumpilly, G.; Thomas, K.; Xiang, W.; Zhang, C.; Aalseth, C.E.; Aguayo, E.; Ely, J.; Fast, J.E.; Hoppe, E.W.; Hossbach, T.W.; Keillor, M.; Kephart, J.D.; Kouzes, R.; Miley, H.S.; Mizouni, L.; Myers, A.W.; Reid, D.; Amman, M.; Bergevin, M.; Chan, Y-D; Detwiler, J.A.; Loach, J.C.; Luke, P.N.; Martin, R.D.; Poon, A.W.P.; Prior, G.; Vetter, K.; Yaver, H.; Avignone, F.T. III; Creswick, R.; Farach, H.; Mizouni, L.; Avignone, Frank Titus; Bertrand Jr, Fred E; Capps, Gregory L; Cooper, Reynold J; Radford, David C; Varner Jr, Robert L; Wilkerson, John F; Yu, Chang-Hong; Back, H.O.; Leviner, L.; Young, A.R.; Back , H.O.; Bai, X.; Hong, H.; Howard, S.; Medlin, D.; Sobolev, V.; Barabash, A.S.; Konovalov, S.I.; Vanyushin, I.; Yumatov, V.; Barbeau, P.S.; Collar, J.I.; Fields, N.; Boswell , M.; Brudanin, V.; Egorov, V.; Gusey, K.; Kochetov, O.; Shirchenko, M.; Timkin, V.; Yakushev, E.; Bugg, W.; Efremenko, M.; Burritt , T.H.; Burritt , T.H.; Busch, M.; Esterline, J.; Swift, G.; Tornow, W.; Hazama, R.; Nomachi, M.; Shima, T.; Finnerty , P.; et al.

    2011-01-01

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in {sup 76}Ge. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  15. The Majorana Experiment

    SciTech Connect

    Aalseth, Craig E.; Aguayo Navarrete, Estanislao; Amman, M.; Avignone, F. T.; Back, Henning O.; Bai, Xinhua; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hong, H.; Hoppe, Eric W.; Hossbach, Todd W.; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Medlin, D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Perevozchikov, O.; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Reid, Douglas J.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Ronquest, M. C.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Sobolev, V.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, V.; Zhang, C.

    2011-08-01

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in 76Ge. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  16. Experiment TGV-2 - Search for double beta decay of 106Cd

    NASA Astrophysics Data System (ADS)

    Rukhadze, N. I.; Briançon, Ch.; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalík, A.; Rukhadze, E. N.; Shitov, Yu. A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.

    2012-08-01

    New limits (at 90% C.L.) on double beta decay of Cd106-T(0νEC/EC)>1.7×1020 yr and T(2νEC/EC)>4.2×1020 yr were obtained in a preliminary calculation of data accumulated for 12900 h on the TGV-2 spectrometer.

  17. Present status and future of the experiment TGV (measurement of double beta decay of48Ca)

    NASA Astrophysics Data System (ADS)

    Brudanin, V. B.; Egorov, V. G.; Kovalík, A.; Kovalenko, V. E.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Timkin, V. V.; Vylov, Ts.; Zaparov, Ch.; Briancon, Ch.; Janout, Z.; Koníček, J.; Kubašta, J.; Pospíšil, S.; Štekl, I.; Vorobel, V.

    1998-02-01

    A short description of experiment TGV (double beta decay of48Ca) is given. The measurement started in the Modane underground laboratory in August 1996. The first result of T {1/2/0 ν } ≥ 4.6 × 1020 years [90% CL] after 2545 hours is presented.

  18. Confirmation of the observation of 2v ββ decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Avignone, F. T.; Brodzinski, R. L.; Guerard, C. K.; Kirpichnikov, I. V.; Miley, H. S.; Pogosov, V. S.; Reeves, J. H.; Starostin, A. S.; Tamanyan, A. G.

    1991-03-01

    Two previous independent reports of 2v ββ decay by the ITEP-YPI Collaboration, T {1}/{2}2 v = (9±1) × 10 20yr (1σ) , and the PNL-USC Collaboration, T {1}/{2}2 v = (1.12 -0.26+0.48) × 10 21yr (2σ) , are confirmed. A 0.25 kg Ge(Li) detector, isotopically enriched to 85% in 76Ge, was operated in the PNL-USC ultralow-background facility in the Homestake gold mine. Following a single correction to the data, a spectrum resembling that observed in the earlier PNL-USC experiment, with about the same intensity per 76Ge atom per year, was observed. The measured half-life is T {1}/{2}2 v = (9.2 -0.4+0.7) × 10 20yr (2σ) .

  19. Mixing of Triaxial and Intruder Configurations in 72,76Ge Studied via Multistep Coulomb Excitation

    NASA Astrophysics Data System (ADS)

    Ayangeakaa, A. D.; Janssens, R. V. F.; Anl Collaboration; Llnl Collaboration; Lbnl Collaboration; U. Of Maryland Collaboration; Csnsm Collaboration

    2015-10-01

    The low-lying states in even-even Ge isotopes have been a subject of intense scrutiny for many years due to the inherent challenge of interpreting their low-energy structure. While several explanations such as vibrational-rotational coupling, 2p-2h intruder mixing and shape coexistence have been proposed, none have been able to satisfactorily reproduce the properties of these low-lying excitations. Recent theoretical calculations have, however, emphasized the importance of the triaxial degree of freedom and, indeed, 76Ge is proposed to exhibit static triaxiality. In this study, the electromagnetic properties of low-lying states in 72,76Ge were investigated via sub-barrier multiple Coulomb excitation with GRETINA and CHICO-2. In the case of 72Ge, the extracted matrix elements seem to agree with the shape coexistence interpretation between the 01+ and 02+ states. However, significant mixing between the wavefunctions of these two states and triaxiality are required to reproduce the overall data. These results and calculations based on a triaxial rotor model with configuration mixing will be presented, and the role of triaxiality will be discussed. Preliminary results for 76Ge will also be highlighted. This work is supported by the DOE, Office of Science, Office of Nuclear Physics under Contract Number DE-AC02-06CH11357, and Grant No. DE-FG02-94ER40834 and DE-FG02-08ER41556.

  20. Nonperturbative renormalization of the neutrinoless double-β operator in p-shell nuclei

    NASA Astrophysics Data System (ADS)

    Shukla, Deepshikha; Engel, Jonathan; Navratil, Petr

    2011-10-01

    We use Lee-Suzuki mappings and related techniques to construct effective two-body p-shell interactions and neutrinoless double-β operators that exactly reproduce the results of large no-core-shell-model calculations of (fictitious) double-β decay in nuclei with mass number A=6. We then apply the effective operators to the (also fictitious) decay of nuclei with A=7, 8, and 10, again comparing with no-core calculations in much larger spaces. The results with the effective two-body operators are generally good. In some cases, however, they differ non-negligibly from the full no-core results, suggesting that three-body corrections to the decay operator in heavier nuclei may be important. An application of our procedure and related ideas to fp-shell nuclei such as 76Ge should be feasible within coupled-cluster theory.

  1. Investigation of double beta decay of 100Mo to excited states of 100Ru

    NASA Astrophysics Data System (ADS)

    Arnold, R.; Augier, C.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Blot, S.; Bongrand, M.; Brudanin, V.; Busto, J.; Caffrey, A. J.; Čermák, P.; Cerna, C.; Chapon, A.; Chauveau, E.; Dragounová, L.; Duchesneau, D.; Durand, D.; Egorov, V.; Eurin, G.; Evans, J. J.; Flack, R.; Garrido, X.; Gómez, H.; Guillon, B.; Guzowski, P.; Hodák, R.; Hubert, P.; Hugon, C.; Hůlka, J.; Jullian, S.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lalanne, D.; Lang, K.; Lemière, Y.; Liptak, Z.; Loaiza, P.; Lutter, G.; Mamedov, F.; Marquet, C.; Mauger, F.; Morgan, B.; Mott, J.; Nemchenok, I.; Nomachi, M.; Nova, F.; Nowacki, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P.; Ramachers, Y. A.; Remoto, A.; Reyss, J. L.; Richards, B.; Riddle, C. L.; Rukhadze, E.; Rukhadze, N.; Saakyan, R.; Sarazin, X.; Shitov, Yu.; Simard, L.; Šimkovic, F.; Smetana, A.; Smolek, K.; Smolnikov, A.; Söldner-Rembold, S.; Soulé, B.; Štekl, I.; Suhonen, J.; Sutton, C. S.; Szklarz, G.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, V. I.; Tretyak, Vl. I.; Umatov, V.; Vilela, C.; Vorobel, V.; Warot, G.; Waters, D.; Žukauskas, A.

    2014-05-01

    Double beta decay of 100Mo to the excited states of daughter nuclei has been studied using a 600 cm3 low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic 100Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of 100Mo. The half-life for the two-neutrino double beta decay of 100Mo to the excited 01+ state in 100Ru is measured to be T1/2=[7.5±0.6(stat)±0.6(syst)]ṡ1020 yr. For other (0ν+2ν) transitions to the 21+, 22+, 02+, 23+ and 03+ levels in 100Ru, limits are obtained at the level of ∼(0.25-1.1)ṡ1022 yr.

  2. First search for Lorentz and C P T violation in double beta decay with EXO-200

    NASA Astrophysics Data System (ADS)

    Albert, J. B.; Barbeau, P. S.; Beck, D.; Belov, V.; Breidenbach, M.; Brunner, T.; Burenkov, A.; Cao, G. F.; Chambers, C.; Cleveland, B.; Coon, M.; Craycraft, A.; Daniels, T.; Danilov, M.; Daugherty, S. J.; Davis, C. G.; Davis, J.; Delaquis, S.; Der Mesrobian-Kabakian, A.; DeVoe, R.; Díaz, J. S.; Didberidze, T.; Dilling, J.; Dolgolenko, A.; Dolinski, M. J.; Dunford, M.; Fairbank, W.; Farine, J.; Feyzbkhsh, S.; Feldmeier, W.; Fierlinger, P.; Fudenberg, D.; Gornea, R.; Graham, K.; Gratta, G.; Hall, C.; Homiller, S.; Hughes, M.; Jewell, M. J.; Jiang, X. S.; Johnson, A.; Johnson, T. N.; Johnston, S.; Karelin, A.; Kaufman, L. J.; Killick, R.; Koffas, T.; Kravitz, S.; Krücken, R.; Kuchenkov, A.; Kumar, K. S.; Leonard, D. S.; Licciardi, C.; Lin, Y. H.; Ling, J.; MacLellan, R.; Marino, M. G.; Mong, B.; Moore, D.; Nelson, R.; Njoya, O.; Odian, A.; Ostrovskiy, I.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Retiére, F.; Rowson, P. C.; Russell, J. J.; Schubert, A.; Sinclair, D.; Smith, E.; Stekhanov, V.; Tarka, M.; Tolba, T.; Tsang, R.; Twelker, K.; Vuilleumier, J.-L.; Vogel, P.; Waite, A.; Walton, J.; Walton, T.; Weber, M.; Wen, L. J.; Wichoski, U.; Wood, J.; Yang, L.; Yen, Y.-R.; Zeldovich, O. Ya.; EXO-200 Collaboration

    2016-04-01

    A search for Lorentz- and C P T -violating signals in the double beta decay spectrum of 136Xe has been performed using an exposure of 100 kg .yr with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz-violation was found, and a two-sided limit of -2.65 ×10-5 GeV <âof(3 )<7.60 ×10-6 GeV (90% C.L.) is placed on the relevant coefficient within the Standard-Model Extension (SME). This is the first experimental study of the effect of the SME-defined oscillation-free and momentum-independent neutrino coupling operator on the double beta decay process.

  3. Simulation of double beta decay in the ''SeXe'' TPC

    NASA Astrophysics Data System (ADS)

    Mauger, F.

    2007-04-01

    In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.

  4. The low background spectrometer TGV II for double beta decay measurements

    NASA Astrophysics Data System (ADS)

    Beneš, P.; Čermák, P.; Gusev, K. N.; Klimenko, A. A.; Kovalenko, V. E.; Kovalík, A.; Rukhadze, N. I.; Salamatin, A. V.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Vylov, Ts.

    2006-12-01

    The low-background multi-HPGe spectrometer TGV II installed in the Modane Underground Laboratory (France) is described in detail and the results of the background measurements are reported. The spectrometer is focused on the double beta decay measurements with two isotopes— 106Cd ( 2νEC/EC mode) and 48Ca ( ββ mode). A basic summary of the physics of ββ decay (especially EC/EC mode) is also given.

  5. Solar neutrino interactions with liquid scintillators used for double beta-decay experiments

    NASA Astrophysics Data System (ADS)

    Ejiri, Hiroyasu; Zuber, Kai

    2016-08-01

    Solar neutrinos interact within double-beta-decay (DBD) detectors and hence will contribute to backgrounds (BGs) for DBD experiments. Background contributions due to solar neutrinos are evaluated for their interactions with atomic electrons and nuclei in liquid scintillation detectors used for DBD experiments. They are shown to be serious BGs for high-sensitivity DBD experiments to search for the Majorana neutrino masses in the inverted and normal hierarchy regions.

  6. Limit on Neutrinoless ββ Decay of Xe136 from the First Phase of KamLAND-Zen and Comparison with the Positive Claim in Ge76

    NASA Astrophysics Data System (ADS)

    Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Kato, R.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakada, T.; Nakamura, K.; Obata, A.; Oki, A.; Ono, Y.; Otani, M.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yamada, S.; Yoshida, H.; Kozlov, A.; Yoshida, S.; Banks, T. I.; Freedman, S. J.; Fujikawa, B. K.; Han, K.; O'Donnell, T.; Berger, B. E.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

    2013-02-01

    We present results from the first phase of the KamLAND-Zen double-beta decay experiment, corresponding to an exposure of 89.5 kg yr of Xe136. We obtain a lower limit for the neutrinoless double-beta decay half-life of T1/20ν>1.9×1025yr at 90% C.L. The combined results from KamLAND-Zen and EXO-200 give T1/20ν>3.4×1025yr at 90% C.L., which corresponds to a Majorana neutrino mass limit of ⟨mββ⟩<(120-250)meV based on a representative range of available matrix element calculations. Using those calculations, this result excludes the Majorana neutrino mass range expected from the neutrinoless double-beta decay detection claim in Ge76, reported by a part of the Heidelberg-Moscow Collaboration, at more than 97.5% C.L.

  7. Studies of A=76 Nuclei with Inelastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Ashley, S. F.; Chakraborty, A.; McEllistrem, M. T.; Peters, E. E.; Yates, S. W.

    2010-11-01

    Following the observation of neutrinoless double-beta decay, an accurate calculation of the nuclear matrix elements (NMEs) is vital to reach quantitative conclusions about the absolute neutrino mass scale as well as the mass hierarchies. Understanding the nature of the wave functions of the participating states for double-beta decay is of fundamental importance in determining the NMEs. One of the prominent candidates for neutrinoless double-beta decay is ^76Ge, which decays to ^76Se. In order to further investigate these nuclei and provide information for the calculation of the NMEs, excitation function and gamma-ray angular distribution measurements utilizing the ^76Ge(n, n'γ) and ^76Se(n, n'γ) reactions were performed at the University of Kentucky. Lifetimes will be determined using the Doppler-shift attenuation method.

  8. Status and perspectives of the COBRA double-beta decay experiment

    NASA Astrophysics Data System (ADS)

    Wilson, J. R.; Cobra Collaboration

    2006-05-01

    The COBRA experiment is going to use a large amount of CdZnTe semiconductor detectors to perform a search for various double-beta-decay modes. The current status of the experiment is presented, as well as first results. Improved half-life limits for the ground-state transitions of 64Zn and 120Te for 0νβ +/EC and 0νECEC have been obtained and the rate of the 4-fold forbidden 113Cd decays has been measured. A short outlook on future activities is also given.

  9. Many-body correlations of QRPA in nuclear matrix elements of double-beta decay

    SciTech Connect

    Terasaki, J.

    2015-10-28

    We present two new ideas on the quasiparticle random-phase approximation (QRPA) approach for calculating nuclear matrix elements of double-beta decay. First, it is necessary to calculate overlaps of the QRPA states obtained on the basis of the ground states of different nuclei. We calculate this overlap using quasiboson vacua as the QRPA ground states. Second, we show that two-particle transfer paths are possible to use for the calculation under the closure approximation. A calculation is shown for {sup 150}Nd→{sup 150}Sm using these two new ideas, and their implication is discussed.

  10. New Limit on the Neutrinoless ββ Decay of 130Te

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Artusa, D. R.; Avignone, F. T., III; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J. W.; Brofferio, C.; Bucci, C.; Capelli, S.; Carbone, L.; Cebrian, S.; Cremonesi, O.; Creswick, R. J.; de Waard, A.; Farach, H. A.; Fiorini, E.; Frossati, G.; Guardincerri, E.; Giuliani, A.; Gorla, P.; Haller, E. E.; McDonald, R. J.; Morales, A.; Norman, E. B.; Nucciotti, A.; Olivieri, E.; Pallavicini, M.; Palmieri, E.; Pasca, E.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Risegari, L.; Rosenfeld, C.; Sangiorgio, S.; Sisti, M.; Smith, A. R.; Torres, L.; Ventura, G.

    2005-09-01

    We report the present results of CUORICINO, a search for neutrinoless double-beta (0νββ) decay of Te130. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at ˜8mK in the Gran Sasso Underground Laboratory. No evidence for (0νββ) decay was found and a new lower limit, T1/20ν≥1.8×1024yr (90% C.L.) is set, corresponding to ⟨mν⟩≤0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.

  11. Investigation of Double Beta Decay of 100Mo to Excited States of 100Ru

    SciTech Connect

    A. J. Caffrey; The NEMO-3 Collaboration

    2014-05-01

    Double beta decay of 100Mo to the excited states of daughter nuclei has been studied using a 600 cm3 low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic 100Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of 100Mo. The half-life for the two-neutrino double beta decay of 100Mo to the excited View the MathML source state in 100Ru is measured to be T1/2=[7.5±0.6(stat)±0.6(syst)]·1020 yr. For other (0?+2?) transitions to the View the MathML source, View the MathML source, View the MathML source, View the MathML source and View the MathML source levels in 100Ru, limits are obtained at the level of ~(0.25–1.1)·1022 yr.

  12. Search for β+/EC double beta decay of 120Te

    NASA Astrophysics Data System (ADS)

    Tomei, C.

    2011-12-01

    We present a search for β+/EC double beta decay of 120Te performed with the CUORICINO experiment, an array of TeO2 cryogenic bolometers. After collecting 0.0573 kgṡy of 120Te, we see no evidence of a signal and therefore set the following limits on the half-life: T1/20ν>1.9ṡ1021 y at 90% C.L. for the 0ν mode and T1/22ν>7.6ṡ1019 y at 90% C.L. for the 2ν mode. These results improve the existing limits by almost three orders of magnitude (four in the case of 0ν mode).

  13. Progress in the use of pixel detectors in double beta decay experiment TGV

    NASA Astrophysics Data System (ADS)

    Jose, J. M.; TGV Collaboration

    2013-12-01

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in 106Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  14. Experiment TGV-2. Search for double beta decay of 106Cd

    NASA Astrophysics Data System (ADS)

    Rukhadze, N. I.; Bakalyarov, A. M.; Briançon, Ch; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Lebedev, V. I.; Rukhadze, E. N.; Mamedov, F.; Shitov, Yu A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Zhukov, S. V.

    2012-07-01

    The search for double beta decay of 106Cd was performed at the Modane underground laboratory (France, 4800 m.w.e.) using the multi-detector spectrometer TGV-2. 16 samples (~13.6 g) of 106Cd with an enrichment of 75% were installed between neighbouring HPGe detectors and measured during 12900 h. New half-life limits (at 90% CL) were obtained for 2νEC/EC decay of 106Cd to the ground state of 106Pd - T1/2 > 4.2 × 1020 y, and for OνEC/EC resonant decay of 106Cd to 2741 keV and 2718 keV excited states of 106Pd - T1/2 > 1.8 × 1020y and T1/2 > 1.6 × 1020y respectively.

  15. Progress in the use of pixel detectors in double beta decay experiment TGV

    SciTech Connect

    Jose, J. M. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a Collaboration: TGV Collaboration

    2013-12-30

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in {sup 106}Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  16. Pixel detectors in double beta decay experiments, a new approach for background reduction

    NASA Astrophysics Data System (ADS)

    Jose, J. M.; Čermák, P.; Štekl, I.; Shitov, Yu. A.; Rukhadze, E. N.; Rukhadze, N. I.; Brudanin, V. B.; Fiederle, M.; Fauler, A.; Loaiza, P.

    2013-08-01

    Double beta decay (ββ) experiments are challenging frontiers in contemporary physics. These experiments have the potential to investigate more about neutrinos (eg. nature and mass). The main challenge for these experiments is the reduction of background. The group at IEAP, CTU in Prague is investigating a new approach using pixel detectors Timepix. Pixel detector offer background reduction capabilities with its ability to identify the particle interaction (from the 2D signature it generates). However, use of pixel detectors has some challenges such as the presence of readout electronics near the sensing medium and heat dissipation. Different aspects of pixel setup (identification of radio-impurities, selection of radio-pure materials) and proposed experimental setup are presented. Also, results of preliminary background measurements (performed on the surface and in the underground laboratories) using the prototype setups are presented.

  17. Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

    NASA Astrophysics Data System (ADS)

    Ejiri, Hiroyasu

    2014-09-01

    Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.

  18. The MAJORANA DEMONSTRATOR for 0νββ: Current Status and Future Plans

    SciTech Connect

    Green, M. P.; Abgrall, N.; Aguayo, Estanislao; Avignone, Frank T.; Barabash, Alexander; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Cuesta, C.; Detwiler, Jason A.; Doe, P. J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, Mark D.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2015-03-24

    The Majorana Demonstrator will search for neutrinoless-double-beta decay in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based neutrinoless-double-beta decay experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the neutrinoless-double-beta decay region of interest (ROI) of no more than 3cnts/(ROI-t-y). The current status of the Demonstrator is discussed, as are plans for its completion.

  19. The First Tests of a Large-Area Light Detector Equipped with Metallic Magnetic Calorimeters for Scintillating Bolometers for the LUMINEU Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Gray, D.; Enss, C.; Fleischmann, A.; Gastaldo, L.; Hassel, C.; Hengstler, D.; Kempf, S.; Loidl, M.; Navick, X. F.; Rodrigues, M.

    2016-02-01

    Future rare-event searches using scintillating crystals need very low background levels for high sensitivity; however, unresolved pile-up can limit this. We present the design and fabrication of large-area photon detectors based on metallic magnetic calorimeters (MMCs), optimized for fast rise times to resolve close pile-up. The first prototypes have been characterized using Fe-55 X-rays and ZnMoO4 crystal scintillation light. A fast intrinsic rise time of 25-30 \\upmu s has been measured and has been compared to the 250 \\upmu s scintillation light pulse rise time constant. The difference indicates that the scintillation process limits the light pulse rise time. The fast rise time allows for a reduction of background due to close pile-up events as well as the study of the inherent crystal scintillation process. MMC-based photon detectors are shown to be a promising tool for scintillating crystal based rare event searches.

  20. The First Tests of a Large-Area Light Detector Equipped with Metallic Magnetic Calorimeters for Scintillating Bolometers for the LUMINEU Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Gray, D.; Enss, C.; Fleischmann, A.; Gastaldo, L.; Hassel, C.; Hengstler, D.; Kempf, S.; Loidl, M.; Navick, X. F.; Rodrigues, M.

    2016-08-01

    Future rare-event searches using scintillating crystals need very low background levels for high sensitivity; however, unresolved pile-up can limit this. We present the design and fabrication of large-area photon detectors based on metallic magnetic calorimeters (MMCs), optimized for fast rise times to resolve close pile-up. The first prototypes have been characterized using Fe-55 X-rays and ZnMoO4 crystal scintillation light. A fast intrinsic rise time of 25-30 \\upmu s has been measured and has been compared to the 250 \\upmu s scintillation light pulse rise time constant. The difference indicates that the scintillation process limits the light pulse rise time. The fast rise time allows for a reduction of background due to close pile-up events as well as the study of the inherent crystal scintillation process. MMC-based photon detectors are shown to be a promising tool for scintillating crystal based rare event searches.

  1. Status of LUMINEU program to search for neutrinoless double beta decay of {sup 100}Mo with cryogenic ZnMoO{sub 4} scintillating bolometers

    SciTech Connect

    Danevich, F. A. Boiko, R. S.; Chernyak, D. M.; Kobychev, V. V.; Bergé, L.; Chapellier, M.; Drillien, A.-A.; Dumoulin, L.; Humbert, V.; Marcillac, P. de; Marnieros, S.; Marrache-Kikuchi, C.; Olivieri, E.; Plantevin, O.; Tenconi, M.; Devoyon, L.; Koskas, F.; and others

    2015-10-28

    The LUMTNEU program aims at performing a pilot experiment on 0ν2β decay of {sup 100}Mo using radiopure ZnMoO{sub 4} crystals enriched in {sup 100}Mo operated as cryogenic scintillating bolometers. Large volume ZnMoO{sub 4} crystal scintillators (∼ 0.3 kg) were developed and tested showing high performance in terms of radiopurity, energy resolution and α/β particle discrimination capability. Zinc molybdate crystal scintillators enriched in {sup 100}Mo were grown for the first time by the low-thermal-gradient Czochralski technique with a high crystal yield and an acceptable level of enriched molybdenum irrecoverable losses. A background level of ∼ 0.5 counts/(yr keV ton) in the region of interest can be reached in a large detector array thanks to the excellent detectors radiopurity and particle discrimination capability, suppression of randomly coinciding events by pulse-shape analysis, and anticoincidence cut. These results pave the way to future sensitive searches based on the LUMTNEU technology, capable of approachingand exploring the inverted hierarchy region of the neutrino mass pattern.

  2. Status of LUMINEU program to search for neutrinoless double beta decay of 100Mo with cryogenic ZnMoO4 scintillating bolometers

    NASA Astrophysics Data System (ADS)

    Danevich, F. A.; Bergé, L.; Boiko, R. S.; Chapellier, M.; Chernyak, D. M.; Coron, N.; Devoyon, L.; Drillien, A.-A.; Dumoulin, L.; Enss, C.; Fleischmann, A.; Gastaldo, L.; Giuliani, A.; Gray, D.; Gros, M.; Hervé, S.; Humbert, V.; Ivanov, I. M.; Juillard, A.; Kobychev, V. V.; Koskas, F.; Loidl, M.; Magnier, P.; Makarov, E. P.; Mancuso, M.; de Marcillac, P.; Marnieros, S.; Marrache-Kikuchi, C.; Navick, X.-F.; Nones, C.; Olivieri, E.; Paul, B.; Penichot, Y.; Pessina, G.; Plantevin, O.; Poda, D. V.; Redon, T.; Rodrigues, M.; Shlegel, V. N.; Strazzer, O.; Tenconi, M.; Torres, L.; Tretyak, V. I.; Vasiliev, Ya. V.; Velazquez, M.; Viraphong, O.

    2015-10-01

    The LUMTNEU program aims at performing a pilot experiment on 0ν2β decay of 100Mo using radiopure ZnMoO4 crystals enriched in 100Mo operated as cryogenic scintillating bolometers. Large volume ZnMoO4 crystal scintillators (˜ 0.3 kg) were developed and tested showing high performance in terms of radiopurity, energy resolution and α/β particle discrimination capability. Zinc molybdate crystal scintillators enriched in 100Mo were grown for the first time by the low-thermal-gradient Czochralski technique with a high crystal yield and an acceptable level of enriched molybdenum irrecoverable losses. A background level of ˜ 0.5 counts/(yr keV ton) in the region of interest can be reached in a large detector array thanks to the excellent detectors radiopurity and particle discrimination capability, suppression of randomly coinciding events by pulse-shape analysis, and anticoincidence cut. These results pave the way to future sensitive searches based on the LUMTNEU technology, capable of approachingand exploring the inverted hierarchy region of the neutrino mass pattern.

  3. Search for double beta decay of 106Cd in TGV-2 experiment

    NASA Astrophysics Data System (ADS)

    Rukhadze, N. I.; Briançon, Ch; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Shitov, Yu A.; Štekl, I.; Timkin, V. V.; Vylov, Ts

    2010-01-01

    Search for double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (4800 m w.e.) using a spectrometer TGV-2 with 32 HPGe detectors. New limits on the half-lives of 0vEC/EC resonant decay - T1/2 >= 1.6 × 1020 y, and on 2vEC/EC decay of 106Cd - T1/2 >= 4.1 × 1020 y (at 90% CL) were obtained from preliminary calculations of experimental data accumulated for 12900 h of measurement of ~13.6 g of 106Cd with enrichment of 75%. The limits on 2vEC/EC decay of 106Cd to the 2+,512 keV and 0+1,1334 keV excited states of 106Pd and on 2vβ+β+ and 2vβ+/EC decay of 106Cd were improved

  4. Results from the Cuoricino (Zero-Neutrino Double Beta) Decay Experiment

    SciTech Connect

    Arnaboldi, C; Artusa, D R; Avignone, F T; Balata, M; Bandac, I; Barucci, M; Beeman, J W; Bellini, F; Brofferio, C; Bucci, C; Capelli, S; Carbone, L; Cebrian, S; Clemenza, M; Cremonesi, O; Creswick, R J; de Ward, A; Didomizio, S D; Dolinski, M J; Farach, H A; Fiorini, E; Frossati, G; Giachero, A; Giuliani, A; Gorla, P; Guardincerri, E; Gutierrez, T D; Haller, E E; Maruyama, R H; McDonald, R J; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Olivieri, E; Pallavicini, M; Palmieri, E; Pasca, E; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Risegari, L; Rosenfeld, C; Sangiorgio, S; Sisti, M; Smith, A R; Torres, L; Ventura, G; Vignati, M

    2007-12-20

    Recent results from the CUORICINO {sup 130}Te zero-neutrino double-beta (0v{beta}{beta}) decay experiment are reported. CUORICINO is an array of 62 tellurium oxide (TeO{sub 2}) bolometers with an active mass of 40.7 kg. It is cooled to {approx}8 mK by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons. It is running in the Laboratori Nazionali del Gran Sasso (LNGS) in Assergi, Italy. These data represent 11.83 kg y or 90.77 mole-years of {sup 130}Te. No evidence for 0v{beta}{beta}-decay was observed and a limit of T{sub 1/2}{sup 0v} ({sup 130}Te) {ge} 3.0 x 10{sup 24} y (90% C.L.) is set. This corresponds to upper limits on the effective mass, , between 0.19 and 0.68eV when analyzed with the many published nuclear structure calculations. In the context of these nuclear models, the values fall within the range corresponding to the claim of evidence of 0v{beta}{beta}-decay by H.V. Klapdor-Kleingrothaus and his co-workers. The experiment continues to acquire data.

  5. GT neutrino-nuclear responses for double beta decays and astro neutrinos

    NASA Astrophysics Data System (ADS)

    Ejiri, H.; Suhonen, J.

    2015-05-01

    Gamow-Teller nuclear matrix elements (NMEs) for pairs of {{β }+/- } {{1}+}≤ftrightarrow {{0}+} ground-state-to-ground-state transitions, in particular their geometric mean NME {{M}m}, are studied. The observed means Mexp m in the medium-heavy mass region are compared with the corresponding single-quasiparticle (qp) NMEs and the means MQRPAm calculated by the proton neutron qp random-phase approximation (pnQRPA). The {{M}m} NMEs turn out to be insensitive to the nucleon occupancy/vacancy amplitudes and to the particle-particle interaction parameter {{g}pp} of the pnQRPA. The observed mean NMEs are found to be reduced by a coefficient k≈ 0.23 relative to the effective qp NMEs and by a coefficient {{k}NM}≈ 0.6 with respect to the pnQRPA NMEs. The reductions associated with the spin isospin correlations and nuclear medium effects, and their impact on nuclear double beta decays and astro-neutrino-nuclear interactions are discussed.

  6. Neutrino nuclear responses for double beta decays and astro neutrino interactions

    NASA Astrophysics Data System (ADS)

    Akimune, Hidetoshi; Ejiri, Hiroyasu

    2015-10-01

    Neutrino nuclear matrix elements (NMEs), are crucial to extract neutrino properties from double beta decay (DBD) experiments, and to evaluate astro-neutrino nuclear interaction and nucleosynthesis rates. NMEs are very sensitive to nucleon nucleon spin-isospin(στ) and nuclear medium effects. Theoretical calculations for NMEs are very hard. Experimental inputs from charge exchange reactions such as (3He,t) and (μ ,νμ xnγ) are very important for evaluating ν-weak NMEs for ββ and astro- ν processes. Gamow-Teller (GT) and spin dipole (SD) NMEs are studied. Note GT is major for 2 νββ , while SD is one of major components for 0 νββ . The observed NMEs for both GT and SD transitions are found to be reduced by kστ ~ 0.4-0.5 due to the nucleon στ correlation and to the one kNM ~ 0.5-0.6 due to the nuclear medium effects such as nucleon isobar (Δ) that are not explicitly included in the pnQRPA. The nuclear medium effects such as N Δ correlations are incorporated by using the effective coupling constant gAeff = (0.5-0.6) ×gA (free) for ββ and astro- ν NMEs.

  7. Search for double beta decay of 106Cd in the TGV-2 experiment

    NASA Astrophysics Data System (ADS)

    Rukhadze, N. I.; Brudanin, V. B.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Kouba, P.; Piquemal, F.; Rozov, S. V.; Rukhadze, E.; Salamatin, A. V.; Šimkovic, F.; Shitov, Yu A.; Štekl, I.; Timkin, V. V.; Yakushev, E. A.

    2016-05-01

    A new experimental run of searching for double beta decay of 106Cd was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the TGV-2 spectrometer, consisting of 32 planar type HPGe detectors with a total sensitive volume of ~400 cm3. 16 foils of 106Cd with an enrichment of 99.57% and a total mass of ~ 23.2 g were inserted between the entrance windows of face-to-face detectors. The limit on 2vEC/EC decay of 106Cd - T1/2 > 3.7 × 1020 y at 90% C.F was obtained from the preliminary calculation of experimental data accumulated for 8198 h of measurement. The limits on the resonance OvEC/EC decay of 106Cd were obtained from the measurement of ~23.2 g of 106Cd with the low-background HPGe spectrometer Obelix lasted 395 h -T1/2 (KF, 2741 keV) > 0.9 × 1020 y and T1/2 (KK, 2718 keV) > 1.4 × 1020 y at 90% C.L.

  8. Double {beta} experiments with the help of scintillation and HPGe detectors at Gran Sasso

    SciTech Connect

    Barabash, A.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; D'Angelo, S.; Di Marco, A.; Bernabei, R.; Boiko, R. S.; Chernyak, D. M.; Danevich, F. A.; Kobychev, V. V.; Kropivyansky, B. N.; Kudovbenko, V. M.; Nagorny, S. S.; Podviyanuk, R. B.; Polischuk, O. G.; Tretyak, V. I.; Vyshnevskyi, I. M.; Yurchenko, S. S.; Brudanin, V. B.; and others

    2011-12-16

    A search for double beta decay of {sup 64,70}Zn, {sup 180,186}W was carried out by using low background ZnWO{sub 4} crystal scintillators, while a CeCl{sub 3} scintillation detector was applied to investigate 2{beta} processes in {sup 136,138,142}Ce. A search for 2{beta} decay of {sup 96,104}Ru, {sup 156,158}Dy, {sup 190,198}Pt and study of 2{nu}2{beta} decay of {sup 100}Mo to the first excited 0{sup +} level of {sup 100}Ru were realized by ultra-low background HPGe {gamma} spectrometry. Moreover, CdWO{sub 4} crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd isotopes were developed to search for 2{beta} decay of {sup 106}Cd and {sup 116}Cd. Finally, experiments aimed to investigate {sup 96,104}Ru and {sup 116}Cd are in progress and a new phase of the experiment to search for 2{beta} processes in {sup 106}Cd is in preparation.

  9. The MAJORANA Experiment

    SciTech Connect

    Aguayo Navarrete, Estanislao; Avignone, F. T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, John; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

    2011-10-01

    The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale {sup 76}Ge neutrinoless double-beta decay ({beta}{beta}(0{nu})-decay) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R and D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.

  10. Off-line data processing and analysis for the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Pandola, L.; Zavarise, P.

    2012-06-01

    Gerda is an experiment designed to look for the neutrinoless double beta decay of 76Ge. The experiment uses an array of high-purity germanium detectors (enriched in 76Ge) directly immersed in liquid argon. Gerda is presently operating eight enriched coaxial detectors (approximately 15 kg of 76Ge) and about 25 new custom-made enriched BEGe detectors will be deployed in the next phase (additional 20kg of 76Ge). The paper describes the Gerda off-line analysis of the high-purity germanium detector data. Firstly we present the signal processing flow, focusing on the digital filters and on the algorithms used. Secondly we discuss the rejection of non-physical events and the data quality monitoring. The analysis is performed completely with the Gerda software framework (Gelatio), designed to support a multi-channel processing and to perform a modular analysis of digital signals.

  11. GERDA - Status and Perspectives

    NASA Astrophysics Data System (ADS)

    Knöpfle, K. T.

    2013-04-01

    The GERmanium Detector Array (GERDA) experiment has been built at the INFN National Gran Sasso Laboratory (LNGS) for the search of neutrinoless double beta (0νββ) decay in 76Ge. It is implementing a new shielding concept by operating bare Ge diodes, enriched in 76Ge, in high purity liquid argon supplemented by a water shield. Phase I data taking of GERDA has started in November 2011. This paper presents preliminary data showing the performance achieved so far, and outlines the preparations for Phase II that aims at reducing backgrounds by another factor of ten.

  12. Double-Beta Decay of ^150Nd to Excited Final States

    NASA Astrophysics Data System (ADS)

    Kidd, M. F.; Esterline, J. H.; Tornow, W.

    2010-11-01

    An experimental study of the two-neutrino double-beta (2νββ) decay of ^150Nd to various excited final states of ^150Sm was performed at Triangle Universities Nuclear Laboratory (TUNL). Such data provide important checks for theoretical models used to predict 0νββ decay half lives. The measurement was performed at the recently established Kimballton Underground Research Facility (KURF) using the TUNL-ITEP ββ decay setup. In this setup, two high-purity germanium detectors were operated in coincidence to detect the deexcitation gamma rays of the daughter nucleus. This coincidence technique, along with the location underground, provides a considerable reduction in background in the regions of interest. This study yields the first results from KURF and the first detection of the coincidence gamma rays from the 0^+1 excited state of ^150Sm. These gamma rays have energies of 334.0 keV and 406.5 keV, and are emitted in coincidence through a 0^+1->2^+1->0^+gs transition. An enriched Nd2O3 sample obtained from Oak Ridge National Laboratory was used. After counting for 391 days, 29 raw events in the region of interest were observed. This count rate gives a half life of T1/2=(0.72^+0.36-0.18±0.04(syst.))x10^20 years, which agrees within error with another recent measurement, in which no coincidence was employed. An updated result will be given.

  13. Neutrinoless double-β decay of 48Ca in the shell model: Closure versus nonclosure approximation

    NASA Astrophysics Data System (ADS)

    Sen'kov, R. A.; Horoi, M.

    2013-12-01

    Neutrinoless double-β decay (0νββ) is a unique process that could reveal physics beyond the Standard Model. Essential ingredients in the analysis of 0νββ rates are the associated nuclear matrix elements. Most of the approaches used to calculate these matrix elements rely on the closure approximation. Here we analyze the light neutrino-exchange matrix elements of 48Ca 0νββ decay and test the closure approximation in a shell-model approach. We calculate the 0νββ nuclear matrix elements for 48Ca using both the closure approximation and a nonclosure approach, and we estimate the uncertainties associated with the closure approximation. We demonstrate that the nonclosure approach has excellent convergence properties which allow us to avoid unmanageable computational cost. Combining the nonclosure and closure approaches we propose a new method of calculation for 0νββ decay rates which can be applied to the 0νββ decay rates of heavy nuclei, such as 76Ge or 82Se.

  14. Physics Division annual report, 1 January-31 December 1984

    SciTech Connect

    Not Available

    1985-10-01

    A brief overview of each of the several areas of research is given with a list of resulting publications. Areas of research include electron-positron annihilation, neutrino interactions, neutrinoless double beta decay of /sup 100/Mo, double beta decay of /sup 76/Ge, antiproton-proton interactions, right-handed gauge boson effects, muon decay asymmetry parameter measurements, supernovae detection, Nemesis search, and detector development. Areas of theoretical research include electroweak interactions, strong interactions, nonperturbative dynamics, supersymmetry, and cosmology and particle physics. 34 figs. (WRF)

  15. Electron-capture branch of {sup 100}Tc and tests of nuclear wave functions for double-{beta} decays.

    SciTech Connect

    Sjue, S. K. L.; Melconian, D.; Garcia, A.; Ahmad, I.; Algora, A.; Aysto, J.; Elomaa, V.-V.; Eronen, T.; Hakala, J.; Hoedl, S.; Kankainen, A.; Kessler, T.; Moore, I. D.; Naabe, F.; Penttila, H.; Rahaman, S.; Saastamoinen, A.; Swanson, H. E.; Weber, C.; Triambak, S.; Deryckx, K.; Physics; Univ. of Washington; Texas A&M Univ.; Univ. of Valencia; Hungarian Academy of Sciences; Univ. of Jyvaskyla; Univ. of Michigan

    2008-12-30

    We present a measurement of the electron-capture branch of {sup 100}Tc. Our value, B(EC) = (2.6 {+-} 0.4) x 10{sup -5}, implies that the {sup 100}Mo neutrino absorption cross section to the ground state of {sup 100}Tc is roughly 50% larger than previously thought. Disagreement between the experimental value and QRPA calculations relevant to double-{beta} decay matrix elements persists. We find agreement with previous measurements of the 539.5- and 590.8-keV {gamma}-ray intensities.

  16. The double beta decay spectrum of sup 100 Mo as measured with a TPC (time projection chamber)

    SciTech Connect

    Elliott, S.R. ); Moe, M.K.; Nelson, M.A.; Vient, M.A. )

    1990-01-01

    A time projection chamber with 8.3 grams of enriched {sup 100}MoO{sub 3} as the central electrode has been operating approximately five months in an underground laboratory. A preliminary analysis of the two-electron sum energy spectrum, the spectrum of those same electrons taken singly, and the opening angle distribution yields a half life of 1.16{sub -0.08}{sup +0.34} {times} 10{sup 19} y at the 68% confidence level for two-neutrino double beta decay of {sup 100}Mo. 9 refs., 8 figs.

  17. Masses of {sup 130}Te and {sup 130}Xe and Double-{beta}-Decay Q Value of {sup 130}Te

    SciTech Connect

    Redshaw, Matthew; Mount, Brianna J.; Myers, Edmund G.; Avignone, Frank T. III

    2009-05-29

    The atomic masses of {sup 130}Te and {sup 130}Xe have been obtained by measuring cyclotron frequency ratios of pairs of triply charged ions simultaneously trapped in a Penning trap. The results, with 1 standard deviation uncertainty, are M({sup 130}Te)=129.906 222 744(16) u and M({sup 130}Xe)=129.903 509 351(15) u. From the mass difference the double-{beta}-decay Q value of {sup 130}Te is determined to be Q{sub {beta}}{sub {beta}}({sup 130}Te)=2527.518(13) keV. This is a factor of 150 more precise than the result of the AME2003 [G. Audi et al., Nucl. Phys. A729, 337 (2003)].

  18. Gamow-Teller strength distributions and stellar weak-interaction rates for ^{76}Ge and ^{82}Se using the deformed pn-QRPA model

    NASA Astrophysics Data System (ADS)

    Nabi, Jameel-Un; Ishfaq, Mavra

    2016-07-01

    We calculate Gamow-Teller strength distributions for β β-decay nuclei ^{76}Ge and ^{82}Se using the deformed pn-QRPA model. We use a deformed Nilsson basis and consider pairing correlations within the deformed BCS theory. Ground state correlations and two-particle and two-hole mixing states were included in our pn-QRPA model. Our calculated strength distributions were compared with experimental data and previous calculation. The total Gamow-Teller strength and centroid placement calculated in our model compares well with the measured value. We calculate β-decay and positron capture rates on ^{76}Ge and ^{82}Se in supernovae environments and compare them to those obtained from experimental data and previous calculation. Our study shows that positron capture rates command the total weak rates at high stellar temperatures. We also calculate energy rates of β-delayed neutrons and their emission probabilities.

  19. Gaseous time projection chambers for rare event detection: results from the T-REX project. I. Double beta decay

    NASA Astrophysics Data System (ADS)

    Irastorza, I. G.; Aznar, F.; Castel, J.; Cebrián, S.; Dafni, T.; Galán, J.; Garcia, J. A.; Garza, J. G.; Gómez, H.; Herrera, D. C.; Iguaz, F. J.; Luzon, G.; Mirallas, H.; Ruiz, E.; Seguí, L.; Tomás, A.

    2016-01-01

    As part of the T-REX project, a number of R&D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. In both this and its companion paper, we compile the main results of the project and give an outlook of application prospects for this detection technique. While in the companion paper we focus on axions and WIMPs, in this paper we focus on the results regarding the measurement of the double beta decay (DBD) of 136Xe in a high pressure Xe (HPXe) TPC. Micromegas of the microbulk type have been extensively studied in high pressure Xe and Xe mixtures. Particularly relevant are the results obtained in Xe + trimethylamine (TMA) mixtures, showing very promising results in terms of gain, stability of operation, and energy resolution at high pressures up to 10 bar. The addition of TMA at levels of ~ 1% reduces electron diffusion by up to a factor of 10 with respect to pure Xe, improving the quality of the topological pattern, with a positive impact on the discrimination capability. Operation with a medium size prototype of 30 cm diameter and 38 cm of drift (holding about 1 kg of Xe at 10 bar in the fiducial volume, enough to contain high energy electron tracks in the detector volume) has allowed to test the detection concept in realistic experimental conditions. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ~ 3% FWHM @ Qββ. This value was experimentally demonstrated for high-energy extended tracks at 10 bar, and is probably improvable down to the ~ 1% FWHM levels as extrapolated from low energy events. In addition, first results on the topological signature information (one straggling track ending in two blobs) show promising

  20. Quantifying the impact of various radioactive background sources on germanium-76 zero-neutrino-double-beta-decay experiments

    NASA Astrophysics Data System (ADS)

    Mizouni, Katarina Leila

    The goal of searching for 0nubetabeta-decay is to probe an absolute neutrino mass scale suggested by the mass-splitting parameters observed by neutrino oscillation experiments. Furthermore, observation of 0nubetabeta-decay is an explicit instance of lepton-number non-conservation. To detect the rare events such as 0nubetabeta-decay, half-lives of the order of 10 25-1027 years have to be probed. Using an active detector with a large volume, such as hundreds of kilograms of HPGe in the case of MAJORANA, and taking efficient measures to mitigate background of cosmic and primordial origins are necessary for the success of a sensitive 0nubetabeta-decay experiment. One focus of the present research is the analysis of data from Cascades, a HPGe crystal array developed at Pacific Northwest National Laboratory in Richland, WA, to determine an upper bound on primordial radiation levels in the cryostat constructed with electroformed copper similar to that electroformed for MAJORANA. It will be shown, however, that there are sources of background much more serious than cryostats in 76Ge experiments. Additionally, experimental applications of the Cascades detector were studied by predicting the sensitivity for a 0nuBB-decay experiment using GEANT4 simulations. Tellurium-130, an even-even nucleus that can undergo 0nubetabeta-decay to either the ground state or first 01+ excited state of 130Xe, was used as an example. The present work developed techniques that will be used for a number of measurements of betabeta-decay half-lives for decays to excited states of the daughter isotopes.

  1. Studies on the double-{beta} decay nucleus {sup 64}Zn using the (d,{sup 2}He) reaction

    SciTech Connect

    Grewe, E.-W.; Baeumer, C.; Dohmann, H.; Frekers, D.; Hollstein, S.; Rakers, S.; Thies, J. H.; Harakeh, M. N.; Berg, A. M. van den; Woertche, H. J.; Johansson, H.; Martinez-Pinedo, G.; Petermann, I.; Sieja, K.; Simon, H.; Langanke, K.; Nowacki, F.; Popescu, L.; Savran, D.; Zilges, A.

    2008-06-15

    The (d,{sup 2}He) charge-exchange reaction on the double-{beta} decay ({beta}{beta}) nucleus {sup 64}Zn has been studied at an incident energy of 183 MeV. The two protons in the {sup 1}S{sub 0} state (indicated as {sup 2}He) were both momentum analyzed and detected simultaneously by the BBS magnetic spectrometer and its position-sensitive detector. {sup 2}He spectra with a resolution of about 115 keV (FWHM) have been obtained allowing identification of many levels in the residual nucleus {sup 64}Cu with high precision. {sup 64}Zn is one of the rare cases undergoing a {beta}{beta} decay in {beta}{sup +} direction. In the experiment presented here, Gamow-Teller (GT{sup +}) transition strengths have been extracted. Together with the GT{sup -} transition strengths from {sup 64}Ni({sup 3}He,t) data to the same intermediate nucleus {sup 64}Cu, the nuclear matrix elements of the {beta}{beta} decay of {sup 64}Zn have been evaluated. Finally, the GT{sup {+-}} distributions are compared with shell-model calculations and a critical assessment is given of the various residual interactions presently employed for the pf shell.

  2. Status of the Majorana Demonstrator

    DOE PAGESBeta

    Cuesta, C.; Abgrall, N.; Arnquist, I. J.; Avignone, III, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; et al

    2015-08-06

    The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 40-kg modular high purity Ge detector array to search for neutrinoless double-beta decay in 76Ge. In view of the next generation of tonne-scale Ge-based neutrinoless double-beta decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. Lastly, the current status of the Demonstrator is discussed, as are plans for its completion.

  3. THE MAJORANA DEMONSTRATOR: OVERVIEW AND STATUS UPDATE

    SciTech Connect

    Keeter, K.; Abgrall, N.; Aguayo, Estanislao; Avignone, F. T.; Barabash, Alexander; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Cuesta, C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, Matthew P.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Kidd, M. F.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; O'Shaughnessy, Mark D.; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Soin, Aleksandr; Strain, J.; Suriano, Anne-Marie; Swift, Gary; Thompson, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2013-04-12

    The MAJORANA DEMONSTRATOR is being constructed at the Sanford Underground Research Facility (SURF) in Lead, SD by the MAJORANA Collaboration to demonstrate the feasibility of a tonne-scale neutrinoless double beta decay experiment based on 76Ge. The observation of neutrinoless double beta decay would indicate that neutrinos can serve as their own antiparticles, thus proving neutrinos to be Majorana particles, and would give information on neutrino masses. Attaining sensitivities for neutrino masses in the inverted hierarchy region requires large tonne-scale detectors with extremely low backgrounds. The DEMONSTRATOR project will show that sufficiently low backgrounds are achievable. A brief description of the detector and a status update on the construction will be given, including the work done at BHSU on acid-etching of Pb shielding bricks.

  4. Status of the Majorana Demonstrator

    SciTech Connect

    Cuesta, C.; Abgrall, N.; Arnquist, Isaac J.; Avignone, Frank T.; Barabash, Alexander S.; Bertrand, F.; Brudanin, V.; Busch, Matthew; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Detwiler, Jason A.; Efremenko, Yuri; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Jasinski, B. R.; Keeter, K.; Kidd, M. F.; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, John L.; O'Shaughnessy, C.; Overman, Nicole R.; Poon, Alan; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Schmitt, C.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, Anne-Marie; Tedeschi, D.; Timkin, V.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, Chang-Hong; Yumatov, Vladimir

    2015-06-09

    The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 40-kg modular high purity Ge detector array to search for neutrinoless double-beta decay in 76Ge. In view of the next generation of tonne-scale Ge-based neutrinoless double-beta decay searches that will probe the neutrino mass scale in the inverted hierarchy region, a major goal of the Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The current status of the Demonstrator is discussed, as are plans for its completion.

  5. Search for double beta processes in 106Cd with enriched 106CdWO4 crystal scintillator in coincidence with four crystals HPGe detector

    NASA Astrophysics Data System (ADS)

    Danevich, F. A.; Belli, P.; Bernabei, R.; Brudanin, V. B.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Chernyak, D. M.; D'Angelo, S.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.; Tupitsyna, I. A.

    2015-10-01

    A radiopure cadmium tungstate crystal scintillator, enriched in 106Cd (106CdWO4), was used to search for double beta decay processes in 106Cd in coincidence with an ultra-low background set-up containing four high purity germanium (HPGe) detectors in a single cryostat. The experiment has been completed after 13085 h of data taking. New improved limits on most of the double beta processes in 106Cd have been set on the level of 1020-1021 yr. Tn particular, the half-life limit on the two neutrino electron capture with positron emission, T1/2 ≥ 1.8 × 1021 yr, reached the region of theoretical predictions.

  6. Search for double beta processes in {sup 106}Cd with enriched {sup 106}CdWO{sub 4} crystal scintillator in coincidence with four crystals HPGe detector

    SciTech Connect

    Danevich, F. A. Chernyak, D. M.; Mokina, V. M.; Belli, P.; Bernabei, R.; D’Angelo, S.; Brudanin, V. B.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Laubenstein, M.; Incicchitti, A.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.; Tupitsyna, I. A.

    2015-10-28

    A radiopure cadmium tungstate crystal scintillator, enriched in {sup 106}Cd ({sup 106}CdWO{sub 4}), was used to search for double beta decay processes in {sup 106}Cd in coincidence with an ultra-low background set-up containing four high purity germanium (HPGe) detectors in a single cryostat. The experiment has been completed after 13085 h of data taking. New improved limits on most of the double beta processes in {sup 106}Cd have been set on the level of 10{sup 20}−10{sup 21} yr. Tn particular, the half-life limit on the two neutrino electron capture with positron emission, T{sub 1/2} ≥ 1.8 × 10{sup 21} yr, reached the region of theoretical predictions.

  7. Status report of the GERDA experiment phase I

    NASA Astrophysics Data System (ADS)

    Riboldi, Stefano; Gerda Collaboration

    2013-08-01

    Phase I of GERDA, aimed at investigating neutrino-less double beta decay of 76Ge is in the active phase since November 2011 at the Gran Sasso National Laboratory of INFN-Italy. GERDA Ge detectors are non-encapsulated and operate immersed in liquid argon, equipped with a front-end readout electronics consisting of cryogenic charge sensitive preamplifiers designed and manufactured to cope with the characteristics of the GERDA experiment (radio-purity, long and resistive cables, etc.). The presentation will report on the current status of the GERDA experiment phase I, focusing on Ge detectors performance in terms of energy resolution, stability over time, counting rate and related issues.

  8. Low Background Signal Readout Electronics for the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Guinn, I.; Abgrall, N.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Efremenko, Yu; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

    2015-05-01

    The Majorana Demonstrator is a planned 40 kg array of Germanium detectors intended to demonstrate the feasibility of constructing a tonne-scale experiment that will seek neutrinoless double beta decay (0νββ) in 76Ge. Such an experiment would require backgrounds of less than 1 count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of the ββ decay. Designing low-noise electronics, which must be placed in close proximity to the detectors, presents a challenge to reaching this background target. This paper will discuss the Majorana collaboration's solutions to some of these challenges.

  9. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    NASA Astrophysics Data System (ADS)

    Tornow, W.; Bhike, Megha

    2015-05-01

    A program is underway at the Triangle Universities Nuclear Laboratory (TUNL) to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  10. Single and Double Beta-Decay Q Values among the Triplet 96Zr, 96Nb, and 96Mo

    NASA Astrophysics Data System (ADS)

    Alanssari, M.; Frekers, D.; Eronen, T.; Canete, L.; Dilling, J.; Haaranen, M.; Hakala, J.; Holl, M.; Ješkovský, M.; Jokinen, A.; Kankainen, A.; Koponen, J.; Mayer, A. J.; Moore, I. D.; Nesterenko, D. A.; Pohjalainen, I.; Povinec, P.; Reinikainen, J.; Rinta-Antila, S.; Srivastava, P. C.; Suhonen, J.; Thompson, R. I.; Voss, A.; Wieser, M. E.

    2016-02-01

    The atomic mass relations among the mass triplet 96Zr, 96Nb, and 96Mo have been determined by means of high-precision mass measurements using the JYFLTRAP mass spectrometer at the IGISOL facility of the University of Jyväskylä. We report Q values for the 96Zr single and double β decays to 96Nb and 96neutrinoless β β -decay nuclear-matrix-element calculations, as these can be simultaneously performed for both decay paths with no further assumptions. The theoretical single β -decay rate has been re-evaluated using a shell-model approach, which indicates a 96Zr single β -decay lifetime within reach of an experimental verification. The uniqueness of the decay also makes such an experiment interesting for an investigation into the origin of the quenching of the axial-vector coupling constant gA.

  11. Development of radiopure cadmium tungstate crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd to search for double beta decay

    SciTech Connect

    Danevich, F. A.; Boiko, R. S.; Chernyak, D. M.; Kobychev, V. V.; Kropivyansky, B. N.; Mokina, V. M.; Nikolaiko, A. S.; Poda, D. V.; Podviyanuk, R. B.; Tretyak, V. I.; Barabash, A. S.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; Bernabei, R.; D'Angelo, S.; Brudanin, V. B.; Cappella, F.; Incicchitti, A.; Caracciolo, V.; and others

    2013-08-08

    Cadmium tungstate crystal scintillators enriched in {sup 106}Cd up to 66% ({sup 106}CdWO{sub 4}) and in {sup 116}Cd up to 82% ({sup 116}CdWO{sub 4}) have been developed. The low radioactive contamination of the crystals measured on the level of ≤ 1.5 mBq/kg ({sup 40}K), ≤ 0.005 - 0.012 mBq/kg ({sup 226}Ra), 0.04 - 0.07 mBq/kg ({sup 228}Th) allows to carry out high sensitivity experiments to search for double beta processes in {sup 106}Cd and {sup 116}Cd.

  12. Neutron-Induced Partial Cross-Section Measurements on ^76Ge Motivated by The Majorana Project 0νββ Decay Search

    NASA Astrophysics Data System (ADS)

    Hilderbrand, S.; Kwan, E.; Angell, C.; Fallin, B.; Howell, C. R.; Hutcheson, A.; Karwowski, H. J.; Kelley, J. H.; Tonchev, A. P.; Tornow, W.; Masters, D. B.; Pedroni, R. S.; Weisel, G. J.

    2007-10-01

    The goal of the Majorana Collaboration is to study 0νββ in order to verify that the neutrino is its own anti-particle; and if so, what is the mass ofthe electron neutrino. Observation of a sharp peak at the ββ endpoint energy will confirm 0νββ as a decay mode, and determination of the partial width will determine the matrix element which depends directly on the electron neutrino mass. In order to observe and verify the existence of 0νββ, it is important to reduce intrinsic, extrinsic,& cosmogenic backgrounds. The Majorana Project will operate with HPGe detectors deep underground to achieve a low-background environment. Recent advances in signal processing and detector design have also enabled scientists to further understand background sources. γ-ray spectra from the interaction of pulsed mono-energetic neutrons with ^76Ge were measured at TUNL using segmented HPGe clover detectors. The neutron-induced partial cross-sections for γ transitions in ^76Ge were measured at En = 8 and 12MeV.

  13. Single and Double Beta-Decay Q Values among the Triplet ^{96}Zr, ^{96}Nb, and ^{96}Mo.

    PubMed

    Alanssari, M; Frekers, D; Eronen, T; Canete, L; Dilling, J; Haaranen, M; Hakala, J; Holl, M; Ješkovský, M; Jokinen, A; Kankainen, A; Koponen, J; Mayer, A J; Moore, I D; Nesterenko, D A; Pohjalainen, I; Povinec, P; Reinikainen, J; Rinta-Antila, S; Srivastava, P C; Suhonen, J; Thompson, R I; Voss, A; Wieser, M E

    2016-02-19

    The atomic mass relations among the mass triplet ^{96}Zr, ^{96}Nb, and ^{96}Mo have been determined by means of high-precision mass measurements using the JYFLTRAP mass spectrometer at the IGISOL facility of the University of Jyväskylä. We report Q values for the ^{96}Zr single and double β decays to ^{96}Nb and ^{96}Mo, as well as the Q value for the ^{96}Nb single β decay to ^{96}Mo, which are Q_{β}(^{96}Zr)=163.96(13), Q_{ββ}(^{96}Zr)=3356.097(86), and Q_{β}(^{96}Nb)=3192.05(16)  keV. Of special importance is the ^{96}Zr single β-decay Q value, which has never been determined directly. The single β decay, whose main branch is fourfold unique forbidden, is an alternative decay path to the ^{96}Zr ββ decay, and its observation can provide one of the most direct tests of the neutrinoless ββ-decay nuclear-matrix-element calculations, as these can be simultaneously performed for both decay paths with no further assumptions. The theoretical single β-decay rate has been re-evaluated using a shell-model approach, which indicates a ^{96}Zr single β-decay lifetime within reach of an experimental verification. The uniqueness of the decay also makes such an experiment interesting for an investigation into the origin of the quenching of the axial-vector coupling constant g_{A}. PMID:26943530

  14. Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils

    NASA Astrophysics Data System (ADS)

    Argyriades, J.; Arnold, R.; Augier, C.; Baker, J.; Barabash, A. S.; Basharina-Freshville, A.; Bongrand, M.; Bourgeois, C.; Breton, D.; Brière, M.; Broudin-Bay, G.; Brudanin, V. B.; Caffrey, A. J.; Carcel, S.; Cebrián, S.; Chapon, A.; Chauveau, E.; Dafni, Th.; Díaz, J.; Durand, D.; Egorov, V. G.; Evans, J. J.; Flack, R.; Fushima, K.-I.; Irastorza, I. G.; Garrido, X.; Gómez, H.; Guillon, B.; Holin, A.; Hommet, J.; Holy, K.; Horkey, J. J.; Hubert, P.; Hugon, C.; Iguaz, F. J.; Ishihara, N.; Jackson, C. M.; Jenzer, S.; Jullian, S.; Kauer, M.; Kochetov, O. I.; Konovalov, S. I.; Kovalenko, V.; Lamhamdi, T.; Lang, K.; Lemière, Y.; Lutter, G.; Luzón, G.; Mamedov, F.; Marquet, Ch.; Mauger, F.; Monrabal, F.; Nachab, A.; Nasteva, I.; Nemchenok, I. B.; Nguyen, C. H.; Nomachi, M.; Nova, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P. P.; Richards, B.; Ricol, J. S.; Riddle, C. L.; Rodríguez, A.; Saakyan, R.; Sarazin, X.; Sedgbeer, J. K.; Serra, L.; Shitov, Yu. A.; Simard, L.; Šimkovic, F.; Söldner-Rembold, S.; Štekl, I.; Sutton, C. S.; Tamagawa, Y.; Szklarz, G.; Thomas, J.; Thompson, R.; Timkin, V.; Tretyak, V.; Tretyak, Vl. I.; Umatov, V. I.; Vála, L.; Vanyushin, I. A.; Vasiliev, R.; Vasiliev, V. A.; Vorobel, V.; Waters, D.; Yahlali, N.; Žukauskas, A.; SuperNEMO Collaboration

    2010-10-01

    The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in 208Tl and 214Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 m2 of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in 208Tl. After more than one year of background measurement, a surface activity of the scintillators of A(Tl208)=1.5 μBq/m2 is reported here. Given this level of background, a larger BiPo detector having 12 m2 of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A(Tl208)<2 μBq/kg (90% C.L.) with a six month measurement.

  15. Prompt γ rays in 77Ge and 75Ge after thermal neutron capture

    NASA Astrophysics Data System (ADS)

    Meierhofer, G.; Grabmayr, P.; Canella, L.; Kudejova, P.; Jolie, J.; Warr, N.

    2012-02-01

    The reactions 74Ge(n, γ) and 76Ge(n, γ) have been measured with cold neutrons generated by the research reactor FRM II near Munich, Germany. The γ rays have been detected by two Compton-suppressed HPGe systems in single and coincidence mode. The number of identified prompt transitions and levels in 77Ge was increased significantly and the decay scheme could be reconstructed for the first time. The decay scheme was also reconstructed for 68 prompt transitions in 75Ge. Previously reported inconsistencies of the γ-ray intensities in the 77Ge β decay could be resolved. In particular, the region around 2039 keV was investigated carefully, since the background to the neutrinoless double-beta decay of 76Ge must be understood well for the upcoming Gerda and Majorana experiments.

  16. Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering at Q2= 0.92 and 1.76 GeV2

    SciTech Connect

    Geraud Laveissiere; Natalie Degrande; Stephanie Jaminion; Christophe Jutier; Luminita Todor; Rachele Di Salvo; L. Van Hoorebeke; Et. Al.

    2004-09-01

    We report a Virtual Compton Scattering study of the proton at low CM energies. We have determined the structure functions P{sub LL} - P{sub TT}/{epsilon} and P{sub LT}, and the electric and magnetic Generalized Polarizabilities (GPs) {alpha}{sub E}(Q{sup 2}) and {beta}{sub M}(Q{sup 2}) at momentum transfer Q{sup 2} = 0.92 and 1.76 GeV{sup 2}. The electric GP shows a strong fall-off with Q{sup 2}, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a fall-off; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q{sup 2}, compensated at higher Q{sup 2} by a paramagnetic contribution from {pi}N intermediate states.

  17. Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2

    SciTech Connect

    Helene Fonvieille, Geraud Laveissiere, Natalie Degrande, Stephanie Jaminion, Christophe Jutier, Luminita Todor, L. Van Hoorebeke, Bryon Anderson, Konrad Aniol, Kathleen Arundell, Gerard Audit, Leonard Auerbach, F. Baker, Maud Baylac, J. Berthot, Pierre Bertin, William Bertozzi, Louis Bimbot, Werner Boeglin, Edward Brash, Vincent Breton, Herbert Breuer, Etienne Burtin, John Calarco, Lawrence Cardman, Christian Cavata, Jian-Ping Chen, Eugene Chudakov, Evaristo Cisbani, Daniel Dale, Cornelis De Jager, Raffaele De Leo, Alexandre Deur, Nicole D'Hose, Gail Dodge, John Domingo, Latifa Elouadrhiri, Martin Epstein, Lars Ewell, John Finn, Kevin Fissum, Guy Fournier, Bernhard Frois, Salvatore Frullani, Christophe Furget, Haiyan Gao, Juncai Gao, Franco Garibaldi, Ashot Gasparian, Shalev Gilad, Ronald Gilman, Oleksandr Glamazdin, Charles Glashausser, Javier Gomez, Viktor Gorbenko, Pierre Guichon, Jens-Ole Hansen, Richard Holmes, Maurik Holtrop, Calvin Howell, Garth Huber, Charles Hyde, Sebastien Incerti, Mauro Iodice, Johann Jardillier, Mark Jones, Seigo Kato, James Kelly, Armen Ketikyan, Mohammad Khayat, Kouichi Kino, Serge Kox, Laird Kramer, Krishna Kumar, Gerfried Kumbartzki, Michael Kuss, Antonio Leone, John LeRose, Richard Lindgren, Nilanga Liyanage, George Lolos, Kazushige Maeda, Sergey Malov, D. Manley, Claude Marchand, Dominique Marchand, Demetrius Margaziotis, Pete Markowitz, Jacques Marroncle, Jacques Martino, Kathy McCormick, James McIntyre, Surik Mehrabyan, Fernand Merchez, Zein-Eddine Meziani, Robert Michaels, Jean Mougey, Sirish Nanda, Amra Offermann, Zisis Papandreou, Charles Perdrisat, R. Perrino, Gerassimos Petratos, Stephane Platchkov, Roman Pomatsalyuk, David Prout, Vina Punjabi, Thierry Pussieux, Gilles Quemener, Ronald Ransome, Oliver Ravel, Jean-Sebastien Real, Yves Roblin, David Rowntree, Gary Rutledge, Paul Rutt, Arunava Saha, Teijiro Saito, Adam Sarty, Tim Smith, Paul Souder, Riad Suleiman, Jeffrey Templon, Tatsuo Terasawa, Raphael Tieulent, Egle Tomasi, Hiroaki Tsubota, Hiroaki Ueno, Paul Ulmer, Guido Urciuoli, Marc Vanderhaeghen, Rob van der Meer, R.Van De Vyver, Pascal Vernin, Branislav Vlahovic, Hakob Voskanyan, Eric Voutier, John Watson, Lawrence Weinstein, Krishni Wijesooriya, Richard Wilson, Bogdan Wojtsekhowski, Dan Zainea, Zilu Zhou, Rachele Di Salvo

    2012-07-01

    Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson Lab using the exclusive photon electroproduction reaction (e p --> e p gamma). This paper gives a detailed account of the analysis which has led to the determination of the structure functions P{sub LL}-P{sub TT}/epsilon and P{sub LT}, and the electric and magnetic generalized polarizabilities (GPs) alpha{sub E}(Q{sup 2}) and beta{sub M}(Q{sup 2}) at values of the four-momentum transfer squared Q{sup 2} = 0.92 and 1.76 GeV{sup 2}. These data, together with the results of VCS experiments at lower momenta, help building a coherent picture of the electric and magnetic GPs of the proton over the full measured Q{sup 2}-range, and point to their non-trivial behavior.

  18. Front-End Electronics Characterization, Production, and QA for the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Elia, Sophia; Majorana Collaboration

    2014-09-01

    The Majorana Demonstrator will search for the neutrinoless double beta decay ββ (0 ν) of the isotope 76Ge. In anticipation of the future tonne-scale experiments, its goal is to demonstrate a path forward to a background rate of one cnt/(ROI-t-y) in a 4 keV region around the Q-value of the 76Ge ββ (0 ν) . Such a background requirement significantly constrains the design of the front end electronics. Low background and low noise qualifications are a necessity. This poster first presents the characterization and noise performance in single and multi detector systems of the front end electronics developed for Majorana. The poster next reviews the full production process and finally describes the Quality Assurance tests developed for the electronics before installation in the experiment. The Majorana Demonstrator will search for the neutrinoless double beta decay ββ (0 ν) of the isotope 76Ge. In anticipation of the future tonne-scale experiments, its goal is to demonstrate a path forward to a background rate of one cnt/(ROI-t-y) in a 4 keV region around the Q-value of the 76Ge ββ (0 ν) . Such a background requirement significantly constrains the design of the front end electronics. Low background and low noise qualifications are a necessity. This poster first presents the characterization and noise performance in single and multi detector systems of the front end electronics developed for Majorana. The poster next reviews the full production process and finally describes the Quality Assurance tests developed for the electronics before installation in the experiment. We acknowledge support from the Office of Nuclear Physics in the DOE Office of Science, the Particle and Nuclear Astrophysics Program of the National Science Foundation and the Russian Foundation for Basic Research.

  19. Analysis techniques for the evaluation of the neutrinoless double-β decay lifetime in 130Te with the CUORE-0 detector

    NASA Astrophysics Data System (ADS)

    Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; di Domizio, S.; di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.; Cuore Collaboration

    2016-04-01

    We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta (0 ν β β ) decay in 130Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0 ν β β decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0 ν β β search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0 ν β β decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0 ν β β decay half-life limits previously reported for CUORE-0, T1/2 0 ν>2.7 ×1024yr , and in combination with the Cuoricino limit, T1/2 0 ν>4.0 ×1024yr .

  20. Search for neutrinoless double-electron capture of 156Dy

    NASA Astrophysics Data System (ADS)

    Finch, S. W.; Tornow, W.

    2015-12-01

    Background: Multiple large collaborations are currently searching for neutrinoless double-β decay, with the ultimate goal of differentiating the Majorana-Dirac nature of the neutrino. Purpose: Investigate the feasibility of resonant neutrinoless double-electron capture, an experimental alternative to neutrinoless double-β decay. Method: Two clover germanium detectors were operated underground in coincidence to search for the de-excitation γ rays of 156Gd following the neutrinoless double-electron capture of 156Dy. 231.95 d of data were collected at the Kimballton underground research facility with a 231.57 mg enriched 156Dy sample. Results: No counts were seen above background and half-life limits are set at O (1016-1018) yr for the various decay modes of 156Dy. Conclusion: Low background spectra were efficiently collected in the search for neutrinoless double-electron capture of 156Dy, although the low natural abundance and associated lack of large quantities of enriched samples hinders the experimental reach.

  1. The search for 0νββ decay with the GERDA experiment: Status and prospects

    NASA Astrophysics Data System (ADS)

    Majorovits, B.

    2015-08-01

    The GERDA experiment is designed to search for neutrinoless double beta decay of 76Ge using HPGe detectors directly immersed into liquid argon. In its first phase the GERDA experiment has yielded a half life limit on this decay of T1/2 0 v>2.1 ṡ1025 . A background model has been developed. It explains the measured spectrum well, taking into account only components with distances to the detectors less then 2 cm. Competitive limits on Majoron accompanied double beta decay have been derived. Phase II of the experiment, now with additional liquid argon veto installed, is presently starting its commissioning phase. First commissioning spectra from calibration measurements are shown, proving that the liquid argon veto leads to a significant reduction of background events.

  2. Thick-target yields of iodine isotopes from proton interactions in Te, and the double-{beta} decay of {sup 128,130}Te

    SciTech Connect

    da Cruz, M.T.F.; Chan, Y.D.; Garcia, A.; Larimer, R.M.; Lesko, K.T.; Norman, E.B.; Rossi, D.F.; Stokstad, R.G.; Zlimen, I.; Wietfeldt, F.E. |; Bardayan, D.W.; Hindi, M.M.

    1993-03-29

    We report thick-target yields of {sup 126,128,130}I from the bombardment of natural Te targets with 15-, 30-, 45- and 50-MeV protons, together with the iodine production cross sections for 1.85- and 5.0-GeV protons. With these data, we have estimated the relative cosmic-ray induced production of {sup 126}Xe, {sup 128}Xe and {sup 13O}Xe in Te ores. These quantities affect the ratio of double-{beta} decay half-lives of {sup 13O}Te and {sup 128}Te. A revised correction of cosmic-ray induced xenon can change the half-life ratio by as much as 10%, from (3.52{plus_minus}0.11) {times} 10{sup {minus}4} to (3.88{plus_minus}0.14) {times} 10{sup {minus}4}.

  3. Thick-target yields of iodine isotopes from proton interactions in Te, and the double-[beta] decay of [sup 128,130]Te

    SciTech Connect

    da Cruz, M.T.F.; Chan, Y.D.; Garcia, A.; Larimer, R.M.; Lesko, K.T.; Norman, E.B.; Rossi, D.F.; Stokstad, R.G.; Zlimen, I. ); Wietfeldt, F.E. California Univ., Berkeley, CA . Dept. of Physics); Bardayan, D.W.; Hindi, M.M. . Dept. of Physics)

    1993-03-29

    We report thick-target yields of [sup 126,128,130]I from the bombardment of natural Te targets with 15-, 30-, 45- and 50-MeV protons, together with the iodine production cross sections for 1.85- and 5.0-GeV protons. With these data, we have estimated the relative cosmic-ray induced production of [sup 126]Xe, [sup 128]Xe and [sup 13O]Xe in Te ores. These quantities affect the ratio of double-[beta] decay half-lives of [sup 13O]Te and [sup 128]Te. A revised correction of cosmic-ray induced xenon can change the half-life ratio by as much as 10%, from (3.52[plus minus]0.11) [times] 10[sup [minus]4] to (3.88[plus minus]0.14) [times] 10[sup [minus]4].

  4. On the neutrinoless double β+/EC decays

    NASA Astrophysics Data System (ADS)

    Suhonen, Jouni

    2013-12-01

    The neutrinoless double positron-emission/electron-capture (0νβ+/EC) decays are studied for the magnitudes of the involved nuclear matrix elements (NMEs). Decays to the ground state, 0gs+, and excited 0+ states are discussed. The participant many-body wave functions are evaluated in the framework of the quasiparticle random-phase approximation (QRPA). Effective, G-matrix-derived nuclear forces are used in realistic single-particle model spaces. The channels β+β+, β+EC, and the resonant neutrinoless double electron capture (R0νECEC) are discussed.

  5. Multiple-resonance phenomenon in neutrinoless double-electron capture

    SciTech Connect

    Eliseev, S.; Goncharov, M.; Blaum, K.; Block, M.; Herfurth, F.; Minaya Ramirez, E.; Droese, C.; Schweikhard, L.; Novikov, Yu. N.; Shabaev, V. M.; Tupitsyn, I. I.; Zubova, N. A.; Zuber, K.

    2011-07-15

    A superposition of multiple resonance states in neutrinoless double-electron capture in {sup 156}Dy has been discovered. Penning-trap mass spectrometry has been used for atomic-mass-difference measurements and careful calculations of electron wave functions and double-hole binding energies have been performed to determine the resonance-enhancement factors. Transitions to four nuclear excited states in the daughter nuclide {sup 156}Gd have been identified as resonantly enhanced, including one with a full resonant enhancement, within the uncertainty of 100 eV. This phenomenon is unique in that it can be used to probe the mechanisms of neutrinoless processes.

  6. On the neutrinoless double β{sup +}/EC decays

    SciTech Connect

    Suhonen, Jouni

    2013-12-30

    The neutrinoless double positron-emission/electron-capture (0νβ{sup +}/EC) decays are studied for the magnitudes of the involved nuclear matrix elements (NMEs). Decays to the ground state, 0{sub gs}{sup +}, and excited 0{sup +} states are discussed. The participant many-body wave functions are evaluated in the framework of the quasiparticle random-phase approximation (QRPA). Effective, G-matrix-derived nuclear forces are used in realistic single-particle model spaces. The channels β{sup +}β{sup +}, β{sup +}EC, and the resonant neutrinoless double electron capture (R0νECEC) are discussed.

  7. Status of the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Cuesta, C.; Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Detwiler, J. A.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2015-10-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44-kg (29 kg 76Ge and 15 kg natGe) to search for neutrinoless double beta decay in 76Ge. The next generation of tonne-scale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a modular implementation to be easily scalable to the next generation experiment. First, the prototype module was assembled; it has been continuously taking data from July 2014 to June 2015. Second, Module 1 with more than half of the total enriched detectors and some natural detectors has been assembled and it is being commissioned. Finally, the assembly of Module 2, which will complete MAJORANA DEMONSTRATOR, is already in progress.

  8. Status of the Majorana Demonstrator

    SciTech Connect

    Cuesta, C.; Buuck, M.; Detwiler, J. A.; Gruszko, J.; Guinn, I. S.; Leon, J.; Robertson, R. G. H.; Abgrall, N.; Bradley, A. W.; Chan, Y.-D.; Mertens, S.; Poon, A. W. P.; Arnquist, I. J.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Bertrand, F. E.; and others

    2015-10-28

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44-kg (29 kg {sup 76}Ge and 15 kg {sup nat}Ge) to search for neutrinoless double beta decay in {sup 76}Ge. The next generation of tonne-scale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a modular implementation to be easily scalable to the next generation experiment. First, the prototype module was assembled; it has been continuously taking data from July 2014 to June 2015. Second, Module 1 with more than half of the total enriched detectors and some natural detectors has been assembled and it is being commissioned. Finally, the assembly of Module 2, which will complete MAJORANA DEMONSTRATOR, is already in progress.

  9. Measurement of the Generalized Polarizabilities of the Proton in Virtual Scattering at Q2=0.92 and 1.76 GeV2: I. Low Energy Expansion Analysis

    SciTech Connect

    Stephanie Jaminion; Natalie Degrande; Geraud Laveissiere; Christophe Jutier; Luminita Todor; Rachele Di Salvo; L. Van Hoorebeke

    2003-12-01

    Virtual Compton Scattering is studied at the Thomas Jefferson National Accelerator Facility at low Center-of-Mass energies, below pion threshold. Following the Low Energy Theorem for the ep {yields} ep gamma process, we obtain values for the two structure functions Pll-Ptt/epsilon and Plt at four-momentum transfer squared Q2=0.92 and 1.76 GeV2.

  10. Deformation effects on the gamow-teller transitions in 76Ge and 76Se by using the deformed Quasi-Particle Random-Phase Approximation

    NASA Astrophysics Data System (ADS)

    Ha, Eunja; Cheoun, Myung-Ki; Kim, K. S.

    2015-10-01

    With the advent of high technology in analyzing the Gamow-Teller (GT) excited states beyond the one nucleon emission threshold, the quenching of the GT strength to the Ikeda sum rule can be recovered by using the high-lying GT states. Moreover, in some nuclei, GT peaks that are stronger than any other peaks appear explicitly in the high-lying excited states. In the current study, we have addressed these high-lying GT (-) excited states within a framework of the deformed quasi-particle random-phase approximation (DQRPA). These high-lying GT (-) excited states are generated due to an increase in particle numbers around the Fermi surface due to an increase in the chemical potential owing to a certain deformation of the nuclei. On the contrary, among the GT(+) excited states, the low-lying ones were favored by an increase in the deformation. The main GT(+/-) transitions were also changed drastically by the deformation. A detailed mechanism leading to the changes in the GT transitions is discussed by studying the shell evolution and the consequent change in the particle numbers in the smearing region caused by the deformation in typical doublebeta-decay nuclei, 76Ge and 76Se.

  11. The majorana experiment

    SciTech Connect

    Rielage, Keith R; Elliott, Steven R; Boswell, Melissa; Gehman, Victor M; Hime, Andrew; Kidd, Mary F; La Roque, Benjamin H; Rodriguez, Larry; Ronquest, Michael C; Salazar, Harry; Steele, David

    2010-12-13

    The MAJORANA Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in {sup 76}Ge. Initially, MAJORANA aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype DEMONSTRATOR module are presented. Our proposed method uses the well-established technique of searching for neutrinoless double-beta decay in high purity Ge-diode radiation detectors that play both roles of source and detector. The use of P-PC Ge detectors present advances in background rejection and a Significantly lower energy threshold than conventional Ge detector technologies. The lower energy threshold opens up a broader and exciting physics program including searches for dark matter and axions concurrent with the double-beta decay search. The DEMONSTRATOR should establish that the backgrounds are low enough to justify scaling to tonne-scale experiment, probe the neutrino effective mass region above 100 meV, and search the low energy region with a sensitivity to dark matter. The DEMONSTRATOR will be sited at the 4850-ft level (4200 m.w.e) of the Sanford Underground Laboratory at Homestake and preparations for construction are currently underway.

  12. A status update on the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Guinn, Ian; Majorana Collaboration

    2015-10-01

    The Majorana Collaboration is seeking neutrinoless double-beta decay (0 νββ), a lepton number violating process that would indicate that the neutrino is a Majorana fermion, in 76Ge. An array of P-type point contact (PPC) high-purity germanium (HPGe) detectors isotopically enriched in 76Ge will be used to perform this search. For inverted hierarchy neutrinos, a tonne-scale array with backgrounds of < 1 ct/ROI-t-y in the 4 keV region of interest (ROI) around the 2039 keV Q-value for double-beta decay in 76Ge will be sensitive to 0 νββ decay. In order to demonstrate the feasibility of such an experiment, the Majorana Demonstrator is being constructed at the 4850' level of the Sanford Underground Research Facility (SURF). The Demonstrator will consist of an array of 40 kg of PPC HPGe detectors, 30 kg of which will be enriched to 87 % in 76Ge, housed in two separate modular cryostats inside of a compact shield. The background goal for the Demonstrator is < 3 cts/ROI-t-y, which is expected to scale down to < 1 ct/ROI-t-y for a tonne-scale experiment. This presentation will contain a status update on the Majorana Demonstrator. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  13. Search for double-beta decay of 136Xe to excited states of 136Ba with the KamLAND-Zen experiment

    NASA Astrophysics Data System (ADS)

    Asakura, K.; Gando, A.; Gando, Y.; Hachiya, T.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, T.; Ishio, S.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obara, S.; Otani, M.; Oura, T.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Tachibana, H.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yoshida, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Winslow, L. A.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

    2016-02-01

    A search for double-beta decays of 136Xe to excited states of 136Ba has been performed with the first phase data set of the KamLAND-Zen experiment. The 01+, 21+ and 22+ transitions of 0 νββ decay were evaluated in an exposure of 89.5 kg ṡyr of 136Xe, while the same transitions of 2 νββ decay were evaluated in an exposure of 61.8 kg ṡyr. No excess over background was found for all decay modes. The lower half-life limits of the 21+ state transitions of 0 νββ and 2 νββ decay were improved to T1/20ν (0+ → 21+) > 2.6 ×1025 yr and T1/22ν (0+ → 21+) > 4.6 ×1023 yr (90% C.L.), respectively. We report on the first experimental lower half-life limits for the transitions to the 01+ state of 136Xe for 0 νββ and 2 νββ decay. They are T1/20ν (0+ → 01+) > 2.4 ×1025 yr and T1/22ν (0+ → 01+) > 8.3 ×1023 yr (90% C.L.). The transitions to the 22+ states are also evaluated for the first time to be T1/20ν (0+ → 22+) > 2.6 ×1025 yr and T1/22ν (0+ → 22+) > 9.0 ×1023 yr (90% C.L.). These results are compared to recent theoretical predictions.

  14. ({sup 3}He,t) reaction on the double {beta} decay nucleus {sup 48}Ca and the importance of nuclear matrix elements

    SciTech Connect

    Grewe, E.-W.; Frekers, D.; Rakers, S.; Baeumer, C.; Dohmann, H.; Thies, J.; Adachi, T.; Fujita, Y.; Shimbara, Y.; Botha, N. T.; Fujita, H.; Hatanaka, K.; Nakanishi, K.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Tamii, A.; Negret, A.; Popescu, L.; Neveling, R.

    2007-11-15

    High-resolution ({sup 3}He,t) measurements on the double {beta}-decay ({beta}{beta}) nucleus {sup 48}Ca have been performed at RCNP (Osaka, Japan) to determine Gamow-Teller (GT{sup -}) transitions to the nucleus {sup 48}Sc, which represents the intermediate nucleus in the second-order perturbative description of the {beta}{beta} decay. At a bombarding energy of E{sub {sup 3}He}=420 MeV an excitation energy resolution of 40 keV was achieved. The measurements were performed at two angle positions of the Grand Raiden Spectrometer (GRS): 0 deg. and 2.5 deg. The results of both settings were combined to achieve angular distributions, by which the character of single transitions could be determined. To characterize the different multipoles, theoretical angular distributions for states with J{sup {pi}}=1{sup +},2{sup +},2{sup -}, and 3{sup +} were calculated using the distorted-wave Born approximation (DWBA) Code DW81. The GT{sup -} strength was extracted up to E{sub x}=7 MeV and combined with corresponding GT{sup +} strength deduced from the {sup 48}Ti(d,{sup 2}He){sup 48}Sc data to calculate the low-energy part of the {beta}{beta}-decay matrix element for the {sup 48}Ca 2{nu}{beta}{beta} decay. We show that after applying trivial momentum corrections to the ({sup 3}He,t) spectrum, the two reaction probes (p,n) and ({sup 3}He,t) reveal a spectral response to an impressively high degree of similarity in the region of low momentum transfer.

  15. Analysis techniques for the evaluation of the neutrinoless double-β decay lifetime in 130Te with the CUORE-0 detector

    DOE PAGESBeta

    Alduino, C.; Alfonso, K.; Artusa, D. R.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; et al

    2016-04-25

    Here, we describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta (0νββ) decay in 130Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0νββ decay search in its own right and functions as a platform to further develop the analysis tools and procedures tomore » be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0νββ search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0νββ decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0νββ decay half-life limits previously reported for CUORE-0, T0ν1/2 > 2.7×1024yr, and in combination with the Cuoricino limit, T0ν1/2 > 4.0×1024yr.« less

  16. A Search for Neutrinoless Tau Decays to Three Leptons

    SciTech Connect

    Kolb, Jeffrey A.

    2008-06-01

    Using approximately 350 million τ+τ- pair events recorded with the BaBar detector at the Stanford Linear Accelerator Center between 1999 and 2006, a search has been made for neutrinoless, lepton-flavor violating tau decays to three lighter leptons. All six decay modes consistent with conservation of electric charge and energy have been considered. With signal selection efficiencies of 5-12%, we obtain 90% confidence level upper limits on the branching fraction β}(τ → ℓℓℓ) in the range (4-8) x 10-8.

  17. Results from Gerda

    NASA Astrophysics Data System (ADS)

    Grabmayr, P.

    2013-02-01

    The Gerda experiment searches for the neutrinoless double beta (0νββ) decay in 76Ge. This lepton number violating process, if found, would prove the Majorana nature of neutrinos. The decay rate permits access to the effective neutrino mass provided accurate nuclear matrix elements are available. Therefore, different isotopes are investigated in various experiments. Gerda is located in the underground Gran Sasso laboratory of INFN and it employs germanium diodes made from isotopically enriched material which are immersed directly into liquid argon serving simultaneously as coolant and as radiation shield. Only screened materials have been selected for holders and preamplifier components as well as other constructional elements in the vicinity of the diodes in order to minimize the background; a muon detection systems reduces the part induced by cosmic radiation. After a successful commissioning, the measurements within Phase I started in November 2011. For the enriched detectors data have been accumulated with an exposure of 6.1 kgṡyr. Overall, a background index of about 0.02 cts/(keVṡkgṡyr) is achieved which is smaller by about a factor of 10 with respect to previous experiments. For the neutrino accompanied double beta decay a preliminary half live of T1/22ν(76Ge)=(1.88±0.10)×1021 yr is deduced.

  18. Results of experiments devoted to searches for 2K capture on {sup 78}Kr and for the double-beta decay of {sup 136}Xe with the aid of proportional counters

    SciTech Connect

    Gavrilyuk, Yu. M.; Gangapshev, A. M.; Zhantudueva, Dj. A.; Kazalov, V. V.; Kuz'minov, V. V.; Panasenko, S. I.; Ratkevich, S. S.; Efendiev, K. V.; Yakimenko, S. P.

    2013-09-15

    A brief description of two low-background setups deployed at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) and intended for searches for two types of double-beta decay of inert-gas isotopes-2K capture on {sup 78}Kr and the double-beta decay of {sup 136}Xe-is given. The two setups in question have similar structures and employ identical large high-pressure copper proportional counters as detectors. Upon a treatment of data from measurements with krypton samples differing in the content of the isotope {sup 78}Kr, the spectrum for an enriched sample revealed an excess of events at a statistical-significance level of about two standard deviations (2{sigma}). If one attributes this excess to 2K(2{nu}) capture on {sup 78}Kr, the respective half-life is T{sub 1/2} = 1.4{sub -0.7}{sup +2.3} Multiplication-Sign 10{sup 22} yr at a 90% C.L. A treatment of data from measurements with xenon samples differing in content of the isotope {sup 136}Xe led to the appearance of an excess of events in the spectrum for an enriched sample at a statistical-significance level of about 2.2{sigma}. If one assumes that this excess is due to the two-neutrino double-beta decay of {sup 136}Xe, then the respective half-life is T{sub 1/2} = 5.8{sub -1.8}{sup +4.7} Multiplication-Sign 10{sup 21} yr.

  19. GERDA: Recent results and future plans

    NASA Astrophysics Data System (ADS)

    Lehnert, Björn

    2014-04-01

    The GERmanium Detector Array (GERDA) is an experiment designed to investigate the neutrinoless double beta decay (0 νββ) in 76Ge. An array of high purity germanium detectors isotopically enriched to 87% of 76Ge is operated within 64 m3 of liquid argon (LAr) at the Laboratori Nazionali del Gran Sasso (LNGS). The experiment aims to explore the 0 νββ half-life up to 1.4×1026 yr with a collected exposure of 100 kg yr separated into two physics phases. The data taking of Phase I started in November 2011 and finished in May 2013 with 21.6 kg yr of exposure and a background index (BI) of 2×10-2cts/(kg yr keV) around the Q-value of 2039 keV before pulse shape cuts. Phase II of the experiment is being prepared with additional 30 Broad Energy Germanium (BEGe) detectors and an instrumentation of the LAr, aiming at a BI reduction by a factor of 10 w.r. to Phase I. This paper will present the GERDA setup and the latest results of the experiment including a new measurement of the 2 νββ spectrum of 76Ge and the decomposition of the background spectrum. The 0 νββ analysis, finished in the meanwhile, will be briefly mentioned. Furthermore, the major improvements planned for Phase II will be discussed.

  20. New Nuclear Structure and Decay Results in the {sup 76}Ge–{sup 76}As System

    SciTech Connect

    Domula, A.R.; Gehre, D.; Zuber, K.; Drohé, J.C.; Nankov, N.; Plompen, A.J.M.; Rouki, C.; Stanoiu, M.; Klix, A.; Buffler, A.; Geduld, D.; Smit, F.D.; Vermeulen, C.; Maleka, P.; Newman, R.T.; Nolte, R.; Wallner, A.

    2014-06-15

    The process of neutrinoless double beta decay (0νββ) plays a key role in modern neutrino physics. Experiments on {sup 76}Ge 0νββ-decay using germanium semiconductors are at the forefront in this field. Due to the extremely low count rates expected for this rare decay, any kind of background event in the detector, especially at energies close to Qββ=2039.006 keV must be avoided. Therefore, a careful investigation on the neutron-induced background was carried out. In this scope experiments investigating the inelastic neutron excitation of the lower lying and the 69{sup th} excited level of {sup 76}Ge have been performed. The existence of a 2040.7 keV gamma-ray, that occurs by the de-excitation of the 69{sup th} excited level, was confirmed. Interfering background from {sup 68}Ge was studied via cross-section measurements of the {sup nat}Ge(n,jn){sup 68}Ge reaction using quasi-monoenergetic neutrons and accelerator mass specrometry for {sup 68}Ge detection. In order to explore the matrix element for the transition between the {sup 76}Ge-{sup 76}As ground states, the electron–capture of {sup 76}As has been measured for the first time.

  1. Neutrinoless double-β decay and nuclear transition matrix elements

    SciTech Connect

    Rath, P. K.

    2015-10-28

    Within mechanisms involving the light Majorana neutrinos, squark-neutrino, Majorons, sterile neutrinos and heavy Majorana neutrino, nuclear transition matrix elements for the neutrinoless (β{sup −}β{sup −}){sub 0ν} decay of {sup 96}Zr, {sup 100}Mo, {sup 128,130}Te and {sup 150}Nd nuclei are calculated by employing the PHFB approach. Effects due to finite size of nucleons, higher order currents, short range correlations, and deformations of parent as well as daughter nuclei on the calculated matrix elements are estimated. Uncertainties in nuclear transition matrix elements within long-ranged mechanisms but for double Majoron accompanied (β{sup −}β{sup −}ϕϕ){sub 0ν} decay modes are 9%–15%. In the case of short ranged heavy Majorona neutrino exchange mechanism, the maximum uncertainty is about 35%. The maximum systematic error within the mechanism involving the exchange of light Majorana neutrino is about 46%.

  2. Neutrinoless double-β decay and nuclear transition matrix elements

    NASA Astrophysics Data System (ADS)

    Rath, P. K.

    2015-10-01

    Within mechanisms involving the light Majorana neutrinos, squark-neutrino, Majorons, sterile neutrinos and heavy Majorana neutrino, nuclear transition matrix elements for the neutrinoless (β-β-)0ν decay of 96Zr, 100Mo, 128,130Te and 150Nd nuclei are calculated by employing the PHFB approach. Effects due to finite size of nucleons, higher order currents, short range correlations, and deformations of parent as well as daughter nuclei on the calculated matrix elements are estimated. Uncertainties in nuclear transition matrix elements within long-ranged mechanisms but for double Majoron accompanied (β-β-ϕϕ)0ν decay modes are 9%-15%. In the case of short ranged heavy Majorona neutrino exchange mechanism, the maximum uncertainty is about 35%. The maximum systematic error within the mechanism involving the exchange of light Majorana neutrino is about 46%.

  3. Results from phase I of the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Wester, Thomas

    2015-10-01

    The GERmanium Detector Array Gerda at the Laboratori Nazionali del Gran Sasso of the INFN in Italy is an experiment dedicated to the search for the neutrinoless double beta (0νββ) decay in 76Ge. The experiment employs high purity germanium detectors enriched in 76Ge inside a 64 m3 cryostat filled with liquid argon. Gerda was planned in two phases of data taking with the goal to reach a half-life sensitivity in the order of 1026 yr. Phase I of Gerda was running from November 2011 until May 2013. With about 18 kg total detector mass, data with an exposure of 21.6 kg.yr was collected and a background index of 0.01 cts/(keV.kg.yr) was achieved in the region of interest. No signal was found for the 0νββ decay and a new limit of T1/2 > 2.1 . 1025 yr (90% C.L.) was obtained, strongly disfavoring the previous claim of observation. Furthermore, the 2νββ decay half-life of 76Ge was measured with unprecedented precision. Other results include new half-life limits of the order of 1023 yr for Majoron emitting double beta decay modes with spectral indices n = 1, 2, 3, 7 and new limits in the order of 1023 yr for 2νββ decays to the first 3 excited states of 76Se. In Phase II, currently in preparation, the detector mass will be doubled while reducing the background index by a factor of 10.

  4. Results from phase I of the GERDA experiment

    SciTech Connect

    Wester, Thomas

    2015-10-28

    The GERmanium Detector Array Gerda at the Laboratori Nazionali del Gran Sasso of the INFN in Italy is an experiment dedicated to the search for the neutrinoless double beta (0νββ) decay in {sup 76}Ge. The experiment employs high purity germanium detectors enriched in {sup 76}Ge inside a 64 m{sup 3} cryostat filled with liquid argon. Gerda was planned in two phases of data taking with the goal to reach a half-life sensitivity in the order of 10{sup 26} yr. Phase I of Gerda was running from November 2011 until May 2013. With about 18 kg total detector mass, data with an exposure of 21.6 kg·yr was collected and a background index of 0.01 cts/(keV·kg·yr) was achieved in the region of interest. No signal was found for the 0νββ decay and a new limit of T{sub 1/2} > 2.1 · 10{sup 25} yr (90% C.L.) was obtained, strongly disfavoring the previous claim of observation. Furthermore, the 2νββ decay half-life of {sup 76}Ge was measured with unprecedented precision. Other results include new half-life limits of the order of 10{sup 23} yr for Majoron emitting double beta decay modes with spectral indices n = 1, 2, 3, 7 and new limits in the order of 10{sup 23} yr for 2νββ decays to the first 3 excited states of {sup 76}Se. In Phase II, currently in preparation, the detector mass will be doubled while reducing the background index by a factor of 10.

  5. The role of g9/2 intruder state in the nuclear matrix elements of 76Ge → 76Se 2νββ(0+ → 0+) decay

    NASA Astrophysics Data System (ADS)

    Valencia, J. P.

    2016-07-01

    I propose a model for the upper-part of pf-shell, which consists of p1/2, p3/2, f5/2 and g9/2 single-particle orbits. While the pf-subshell (or d ˜s -subshell, i.e. η ˜=2 ,s˜1 /2,d˜3 /2,d˜5 /2) is governed by the SU˜S ˜T(4 )⊗U˜L ˜(6 ) symmetry, the g9/2 intruder state is governed by the seniority model. The nuclear states of 76Ge and 76Se are expressed as direct products of the d ˜s subshell component and the g-subshell one. The five-dimensional quasispin formalism with seniority zero restriction is used for a classification in the g-subshell. In the d ˜s -subshell, for each configuration [Mπ,Mν]d ˜s I choose only the most symmetric U˜L ˜(6 ) representations with total pseudo-spin S ˜=0 . Therefore, all the configurations are given by (0 Y 0 ˜) {4P2Y ˜} and (0 Y 0 -20 ˜) {4P +12Y -2 ˜} for 76Ge and 76Se, respectively with Y = 6-(nν - nπ)/2 and P = (4 - nπ)/2. I derive an explicit expression for the NME of the 2νββ(0+ → 0+) in the closure approximation.

  6. Low background aspects of GERDA

    SciTech Connect

    Simgen, Hardy

    2011-04-27

    The GERDA experiment operates bare Germanium diodes enriched in {sup 76}Ge in an environment of pure liquid argon to search for neutrinoless double beta decay. A very low radioactive background is essential for the success of the experiment. We present here the research done in order to remove radio-impurities coming from the liquid argon, the stainless steel cryostat and the front-end electronics. We found that liquid argon can be purified efficiently from {sup 222}Rn. The main source of {sup 222}Rn in GERDA is the cryostat which emanates about 55 mBq. A thin copper shroud in the center of the cryostat was implemented to prevent radon from approaching the diodes. Gamma ray screening of radio-pure components for front-end electronics resulted in the development of a pre-amplifier with a total activity of less than 1 mBq {sup 228}Th.

  7. Updated constraints on the light-neutrino exchange mechanisms of the 0νββ-decay

    NASA Astrophysics Data System (ADS)

    Štefánik, Dušan; Dvornický, Rastislav; Šimkovic, Fedor

    2015-10-01

    The neutrinoless double-beta (0νββ) decay associated with light neutrino exchange mechanisms, which are due to both left-handed V-A and right-handed V+A leptonic and hadronic currents, is discussed by using the recent progress achieved by the GERDA, EXO and KamlandZen experiments. The upper limits for effective neutrino mass mββ and the parameters <λ> and <η> characterizing the right handed current mechanisms are deduced from the data on the 0νββ-decay of 76Ge and 136Xe using nuclear matrix elements calculated within the nuclear shell model and quasiparticle random phase approximation and phase-space factors calculated with exact Dirac wave functions with finite nuclear size and electron screening. The careful analysis of upper constraints on effective lepton number violating parameters assumes a competition of the above mechanisms and arbitrary values of involved CP violating phases.

  8. GERDA Status Report: Results from Commissioning

    NASA Astrophysics Data System (ADS)

    Cattadori, Carla Maria

    2012-07-01

    In June 2010 GERDA, designed to search for neutrinoless double beta decay of 76Ge, started the commissioning, with a pilot string of 3 non-enriched Ge detector. One year later 3 enrGedetectors were added, and operated for ~ 4 months. This contribution summarizes the first year of work, the updated evaluation of the setup background, the strategies we implemented to mitigate the most serious background source we faced with, i.e. 42Ar-42K: the 42Ar activity measured in the final quasi-field free configuration is 0.23 ± 0.03 cts/(kg.d) corresponding to 104 Bq/kg; this is assuming an homogeneous and isotropic distribution of the daugther nucleus, 42K, around the detector array. The background index measured with the enrGe 3-detector array is 0.045+0.015-0.011 cts/(keV-kg-y).

  9. Current experiments in germanium 0 ν β β search -- GERDA and MAJORANA

    NASA Astrophysics Data System (ADS)

    von Sturm, K.

    2015-01-01

    There are unanswered questions regarding neutrino physics that are of great interest for the scientific community. For example the absolute masses, the mass hierarchy and the nature of neutrinos are unknown up to now. The discovery of neutrinoless double beta decay (0νββ) would prove the existence of a Majorana mass, which would be linked to the half-life of the decay, and would in addition provide an elegant solution for the small mass of the neutrinos via the seesaw mechanism. Because of an existing discovery claim of 0νββ of 76Ge and the excellent energy resolution achievable, germanium is of special interest in the search for 0νββ . In this article the state of the art of germanium 0νββ search, namely the GERDA experiment and MAJORANA demonstrator, is presented. In particular, recent results of the GERDA collaboration, which strongly disfavour the above mentioned claim, are discussed.

  10. The MAJORANA DEMONSTRATOR radioassay program

    NASA Astrophysics Data System (ADS)

    Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunmore, J. A.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Finnerty, P.; Galindo-Uribarri, A.; Gehman, V. M.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Massarczyk, R.; Meijer, S.; Mertens, S.; Miller, M. L.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Steele, D.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2016-08-01

    The MAJORANA collaboration is constructing the MAJORANA DEMONSTRATOR at the Sanford Underground Research Facility at the Homestake gold mine, in Lead, SD. The apparatus will use Ge detectors, enriched in isotope 76Ge, to demonstrate the feasibility of a large-scale Ge detector experiment to search for neutrinoless double beta decay. The long half-life of this postulated process requires that the apparatus be extremely low in radioactive isotopes whose decays may produce backgrounds to the search. The radioassay program conducted by the collaboration to ensure that the materials comprising the apparatus are sufficiently pure is described. The resulting measurements from gamma-ray counting, neutron activation and mass spectroscopy of the radioactive-isotope contamination for the materials studied for use in the detector are reported. We interpret these numbers in the context of the expected background for the experiment.

  11. The Majorana Parts Tracking Database

    DOE PAGESBeta

    Abgrall, N.

    2015-01-16

    The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76Ge. The Majorana Parts Tracking Database is used to record the history of components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provides a great logistics benefit and an important quality assurance reference during construction. In addition, the location history of parts provides an estimate of their exposure to cosmic radiation.more » In summary, a web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.« less

  12. Commissioning the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Xu, Wenqin; Majorana Collaboration

    2016-03-01

    The Majorana Demonstrator deploys high purity germanium (HPGe) detector modules to search for neutrinoless double beta (0 νββ) decay in 76Ge. The experiment is aimed at demonstrating the technical feasibility and low backgrounds for a next generation Ge-based BBz experiment. The program of testing and commissioning the Demonstrator modules is a critical step to debug and improve the experimental apparatus, to establish and refine operational procedures, and to develop data analysis tools. In this talk, we will discuss our experience commissioning the Demonstrator modules and show how this program leads to successful data-taking. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and the Sanford Underground Research Facility.

  13. Detector Characterization for the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Gilliss, Thomas; Majorana Collaboration

    2015-04-01

    The MAJORANA DEMONSTRATOR (MJD) is a neutrinoless double-beta decay (0 νββ) search, in the isotope 76Ge . Seeking measurement of the 0 νββ lifetime, and exploration of additional physics, MJD employs high-purity Ge detectors possessing superior energy resolution down to a low threshold. Characterization of these p-type point contact detectors is essential to understanding the backgrounds and sensitivity of the experiment. Progress in characterizing MJD detectors will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  14. Analysis techniques for background rejection at the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Cuesta, C.; Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Detwiler, J. A.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2015-08-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 40- kg modular HPGe detector array to search for neutrinoless double beta decay in 76Ge. In view of the next generation of tonne-scale Ge-based 0νβ β-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The background rejection techniques to be applied to the data include cuts based on data reduction, pulse shape analysis, event coincidences, and time correlations. The Point Contact design of the DEMONSTRATOR's germanium detectors allows for significant reduction of gamma background.

  15. The MAJORANA DEMONSTRATOR for 0νββ: Current Status and Future Plans

    NASA Astrophysics Data System (ADS)

    Green, M. P.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    The MAJORANA DEMONSTRATOR will search for neutrinoless-double-beta decay (0νββ) in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based 0νββ experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the 0νββ region of interest (ROI) of no more than 3 counts in the 0νββ-decay ROI per tonne of target isotope per year (cnts/(ROI-t-y)). The current status of the Demonstrator is discussed, as are plans for its completion.

  16. A Dark Matter Search with MALBEK

    NASA Astrophysics Data System (ADS)

    Giovanetti, G. K.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    The Majorana Demonstrator is an array of natural and enriched high purity germanium detectors that will search for the neutrinoless double-beta decay of 76Ge and perform a search for weakly interacting massive particles (WIMPs) with masses below 10 GeV. As part of the Majorana research and development efforts, we have deployed a modified, low-background broad energy germanium detector at the Kimballton Underground Research Facility. With its sub-keV energy threshold, this detector is sensitive to potential non-Standard Model physics, including interactions with WIMPs. We discuss the backgrounds present in the WIMP region of interest and explore the impact of slow surface event contamination when searching for a WIMP signal.

  17. Production and test of isotopically modified Ge detectors for GERDA

    SciTech Connect

    Budjas, D.

    2011-07-01

    The viability of producing BEGe-type detectors from isotopically modified germanium for the GERDA experiment is demonstrated by a complete test of the supply chain. GERDA is built to search for neutrinoless double beta (0v{beta}{beta}) decay of Ge using high-purity germanium detectors made of material enriched in {sup 76}Ge. To reach a sensitivity for 0v{beta}{beta} decay of <1.4 x 10{sup 26} years, new active background suppression techniques are necessary. BEGe detectors enable a capability to efficiently identify and reject background events, while keeping large acceptance of 0v{beta}{beta} decay signal, by using novel pulse shape discrimination (PSD) techniques. The PSD as well as spectroscopic performance of prototype BEGe detectors from isotopically modified Ge was verified by comprehensive testing. (authors)

  18. Use of Electrodeposition for Sample Preparation and Rejection Rate Prediction for Assay of Electroformed Ultra High Purity Copper for 232Th and 238U Prior to Inductively Coupled Plasma Mass Spectrometry (ICP/MS)

    SciTech Connect

    Hoppe, Eric W.; Aalseth, Craig E.; Brodzinski, Ronald L.; Day, Anthony R.; Farmer, Orville T.; Hossbach, Todd W.; McIntyre, Justin I.; Miley, Harry S.; Mintzer, Esther E.; Seifert, Allen; Smart, John E.; Warren, Glen A.

    2008-07-01

    The search for neutrinoless double beta decay in 76Ge has driven the need for ultra-low background Ge detectors shielded by electroformed copper of ultra-high radiopurity (<0.1µBq/kg). Although electrodeposition processes are almost sophisticated enough to produce copper of this purity, to date there are no methods sensitive enough to assay it. Inductively-coupled plasma mass spectrometry (ICP/MS) can detect thorium and uranium at femtogram levels, but in the past, this assay has been hindered by high copper concentrations in the sample. Electrodeposition of copper samples removes copper from the solution while selectively concentrating thorium and uranium contaminants to be assayed by ICP/MS. Spiking 232Th and 238U into the plating bath simulates low purity copper and allows for the calculation of the electrochemical rejection rate of thorium and uranium in the electroplating system. This rejection value will help to model plating bath chemistry.

  19. Assembly and design of the germanium detectors for the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Jasinski, Ben; Majorana Collaboration

    2014-09-01

    The Majorana Demonstrator is a neutrino-less double-beta decay experiment being carried out at the Sanford Underground Research Facility, in South Dakota. The Demonstrator will consist of 30 kg of germanium detectors enriched in 76 Ge. Each P-type Point Contact detector is arranged in a string configuration, utilizing novel front-end electronics, cables, connectors, and mounts, fabricated from radio-pure materials. The assembly of the strings is carried out 4850 feet underground to reduce cosmologically induced backgrounds. To further reduce backgrounds, strings are assembled in a nitrogen-filled glovebox. This talk will give an overview of the design and the assembly of the detector strings for the Majorana Demonstrator.

  20. Simulation-based Validation of Pulse Shape Discrimination for the MARJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Shanks, Benjamin

    2014-03-01

    The MAJORANA DEMONSTRATOR, currently under construction at Sanford Underground Research Facility, will search for neutrinoless double beta decay (0 νββ) in 76Ge. Given the extremely long half-life of this decay, the experiment aims to reduce background to < 3 counts/tonne-year in the 4-keV-wide region of interest. Because of the unique characteristics of the p-type point contact (PPC) detectors used in the DEMONSTRATOR, pulse shape analysis (PSA) can be used to discriminate candidate 0 νββ signal events from background gamma rays. A simulation framework has been written to validate the PSA algorithms. Described here are results of validation studies, comparing PSA results on simulated and experimental data. This work is supported by grants from the DOE Office of Nuclear Physics and the NSF Particle Astrophysics program.

  1. The MAJORANA Parts Tracking Database

    NASA Astrophysics Data System (ADS)

    Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J. Diaz; Leviner, L. E.; Loach, J. C.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O`Shaughnessy, C.; Overman, N. R.; Petersburg, R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Suriano, A. M.; Tedeschi, D.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2015-04-01

    The MAJORANA DEMONSTRATOR is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76Ge. The MAJORANA Parts Tracking Database is used to record the history of components used in the construction of the DEMONSTRATOR. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provide a great logistics benefit and an important quality assurance reference during construction. In addition, the location history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.

  2. A Dark Matter Search with MALBEK

    SciTech Connect

    Giovanetti, G. K.; Abgrall, N.; Aguayo, Estanislao; Avignone, Frank T.; Barabash, Alexander S.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Cuesta, C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, C.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2015-06-01

    The Majorana Demonstrator is an array of natural and enriched high purity germanium detectors that will search for the neutrinoless double-beta decay of 76Ge and perform a search for weakly interacting massive particles (WIMPs) with masses below 10 GeV. As part of the Majorana research and development efforts, we have deployed a modified, low-background broad energy germanium detector at the Kimballton Underground Research Facility. With its sub-keV energy threshold, this detector is potentially sensitive to non-Standard Model physics, including interactions with WIMPs. We discuss the backgrounds present in the WIMP region of interest and present results from a WIMP search with 221.49 live days of data from this detector.

  3. The MAJORANA DEMONSTRATOR for 0νββ: Current status and future plans

    SciTech Connect

    Green, M. P.; Abgrall, N.; Aguayo, E.; Avignone, III, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y. -D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, II, D. G.; Poon, A. W.P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G.H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C. -H.; Yumatov, V.

    2015-01-01

    The Majorana Demonstrator will search for neutrinoless-double-beta decay (0νββ) in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based 0νββ experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the 0νββ region of interest (ROI) of no more than 3 counts in the 0νββ-decay ROI per tonne of target isotope per year (cnts/(ROI-t-y)). The current status of the Demonstrator is discussed, as are plans for its completion.

  4. The Majorana Parts Tracking Database

    SciTech Connect

    Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J. Diaz; Leviner, L. E.; Loach, J. C.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O׳Shaughnessy, C.; Overman, N. R.; Petersburg, R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Suriano, A. M.; Tedeschi, D.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C. -H.; Yumatov, V.; Zhitnikov, I.

    2015-04-01

    The MAJORANA DEMONSTRATOR is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76Ge. The MAJORANA Parts Tracking Database is used to record the history of components used in the construction of the DEMONSTRATOR. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provides a great logistics benefit and an important quality assurance reference during construction. In addition, the location history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radiopurity required for this rare decay search.

  5. Analysis techniques for background rejection at the MAJORANA DEMONSTRATOR

    SciTech Connect

    Cuesta, C.; Buuck, M.; Detwiler, J. A.; Gruszko, J.; Guinn, I. S.; Leon, J.; Robertson, R. G. H.; Abgrall, N.; Bradley, A. W.; Chan, Y-D.; Mertens, S.; Poon, A. W. P.; Arnquist, I. J.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Bertrand, F. E.; and others

    2015-08-17

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 40- kg modular HPGe detector array to search for neutrinoless double beta decay in {sup 76}Ge. In view of the next generation of tonne-scale Ge-based 0νβ β-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The background rejection techniques to be applied to the data include cuts based on data reduction, pulse shape analysis, event coincidences, and time correlations. The Point Contact design of the DEMONSTRATOR’s germanium detectors allows for significant reduction of gamma background.

  6. The Majorana Demonstrator for 0νββ: Current Status and Future Plans

    SciTech Connect

    Green, Matthew P.; Avignone, F. T.; Galindo-Uribarri, Alfredo; Radford, David C; Romero-Romero, Elisa; Varner, Jr, Robert L; White, Brandon R; Wilkerson, J. F.

    2015-01-01

    The Majorana Demonstrator will search for neutrinoless-double-beta decay (0νββ) in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based 0νββ experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the 0νββ region of interest (ROI) of no more than 3cnts/(ROI-t-y). The current status of the Demonstrator is discussed, as are plans for its completion.

  7. Astroparticle physics with a customized low-background broad energy Germanium detector

    NASA Astrophysics Data System (ADS)

    Aalseth, C. E.; Amman, M.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Bugg, W.; Burritt, T. H.; Busch, M.; Capps, G.; Chan, Y.-D.; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, J. A.; Diaz, J.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Ely, J.; Esterline, J.; Farach, H.; Fast, J. E.; Fields, N.; Finnerty, P.; Fujikawa, B.; Fuller, E.; Gehman, V. M.; Giovanetti, G. K.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Harper, G. C.; Hazama, R.; Henning, R.; Hime, A.; Hoppe, E. W.; Hossbach, T. W.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Keillor, M.; Keller, C.; Kephart, J. D.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; Leviner, L.; Loach, J. C.; Luke, P. N.; Macmullin, S.; Marino, M. G.; Martin, R. D.; Mei, D.-M.; Miley, H. S.; Miller, M. L.; Mizouni, L.; Meyers, A. W.; Nomachi, M.; Orrell, J. L.; Peterson, D.; Phillips, D. G.; Poon, A. W. P.; Prior, G.; Qian, J.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Rodriguez, L.; Rykaczewski, K. P.; Salazar, H.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Steele, D.; Strain, J.; Swift, G.; Thomas, K.; Timkin, V.; Tornow, W.; van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, K.; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Zhang, C.; Zimmerman, S.; M Ajorana Collaboration

    2011-10-01

    The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/ c2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.

  8. MaGe - a GEANT4-based Monte Carlo Application Framework for Low-background Germanium Experiments

    SciTech Connect

    Boswell, M.; Chan, Yuen-Dat; Detwiler, Jason A.; Finnerty, P.; Henning, R.; Gehman, Victor; Johnson, Robert A.; Jordan, David V.; Kazkaz, Kareem; Knapp, Markus; Kroninger, Kevin; Lenz, Daniel; Leviner, L.; Liu, Jing; Liu, Xiang; MacMullin, S.; Marino, Michael G.; Mokhtarani, A.; Pandola, Luciano; Schubert, Alexis G.; Schubert, J.; Tomei, Claudia; Volynets, Oleksandr

    2011-06-13

    We describe a physics simulation software framework, MAGE, that is based on the GEANT4 simulation toolkit. MAGE is used to simulate the response of ultra-low radioactive background radiation detectors to ionizing radiation, specifically the MAJ ORANA and GE RDA neutrinoless double-beta decay experiments. MAJ ORANA and GERDA use high-purity germanium technology to search for the neutrinoless double-beta decay of the 76 Ge isotope, and MAGE is jointly developed between these two collaborations. The MAGE framework contains simulated geometries of common objects, prototypes, test stands, and the actual experiments. It also implements customized event generators, GE ANT 4 physics lists, and output formats. All of these features are available as class libraries that are typically compiled into a single executable. The user selects the particular experimental setup implementation at run-time via macros. The combination of all these common classes into one framework reduces duplication of efforts, eases comparison between simulated data and experiment, and simplifies the addition of new detectors to be simulated. This paper focuses on the software framework, custom event generators, and physics list.

  9. Astroparticle physics with a customized low-background broad energy Germanium detector

    SciTech Connect

    Aalseth, Craig E.; Amman, M.; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fujikawa, Brian; Fuller, Erin S.; Gehman, Victor M.; Giovanetti, G. K.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Hossbach, Todd W.; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Prior, Gersende; Qian, J.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Rykaczewski, Krzysztof P.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.; Zimmerman, S.

    2011-10-01

    The Majorana Collaboration is building the Majorana Demonstrator, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The Majorana Demonstrator will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c² mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the Majorana Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.

  10. Methods for deploying ultra-clean detectors

    NASA Astrophysics Data System (ADS)

    Schubert, Alexis

    2008-04-01

    Next-generation underground experiments, such as searches for neutrinoless double-beta decay and dark matter experiments, will perform high-sensitivity measurements that require extremely low backgrounds. The Majo-ra-na Collaboration ootnotetextF.T. Avignone III (2007) arXiv:0711.4808v1 proposes such an experiment to search for neutrinoless double-beta decay using an array of germanium crystals enriched in ^76Ge. The design of the Majo-ra-na experiment must minimize backgrounds while meeting criteria for electrical signal quality, structural integrity, and thermal cooling characteristics. Recent work has addressed detector deployment in ultra low-background environments. Advances have been made in fabrication of radiologically pure copper parts. Prototype designs for detector support structures reduce backgrounds by minimizing component mass and making use of ultra-pure materials. This talk will describe the design and use of cryostat test-stands to investigate the performance of prototype designs for detector strings. While Majo-ra-na uses germanium detectors, the design considerations and progress made by the collaboration are applicable to other detector technologies and fields of research.

  11. Experience from operating germanium detectors in GERDA

    NASA Astrophysics Data System (ADS)

    Palioselitis, Dimitrios; GERDA Collaboration

    2015-05-01

    Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76Ge was set (T-0ν1/2 > 2.1 · 1025 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats.

  12. Production and characterization of 228Th calibration sources with low neutron emission for GERDA

    NASA Astrophysics Data System (ADS)

    Baudis, L.; Benato, G.; Carconi, P.; Cattadori, C.; De Felice, P.; Eberhardt, K.; Eichler, R.; Petrucci, A.; Tarka, M.; Walter, M.

    2015-12-01

    The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinoless double beta decay of 76Ge. In view of the GERDA Phase II data collection, four new 228Th radioactive sources for the calibration of the germanium detectors enriched in 76Ge have been produced with a new technique, leading to a reduced neutron emission rate from (α, n) reactions. The gamma activities of the sources were determined with a total uncertainty of ~4% using an ultra-low background HPGe detector operated underground at LNGS. The neutron emission rate was determined using a low background LiI(Eu) detector and a 3He counter at LNGS. In both cases, the measured neutron activity is ~10-6 n/(sṡBq), with a reduction of about one order of magnitude with respect to commercially available 228Th sources. Additionally, a specific leak test with a sensitivity to leaks down to ~10 mBq was developed to investigate the tightness of the stainless steel capsules housing the sources after their use in cryogenic environment.

  13. Isotopically modified Ge detectors for GERDA: from production to operation

    NASA Astrophysics Data System (ADS)

    Budjáš, D.; Agostini, M.; Baudis, L.; Bellotti, E.; Bezrukov, L.; Brugnera, R.; Cattadori, C.; di Vacri, A.; Falkenstein, R.; Garfagnini, A.; Georgi, S.; Grabmayr, P.; Hegai, A.; Hemmer, S.; Hult, M.; Janicskó Csáthy, J.; Kornoukhov, V.; Lehnert, B.; Lubashevskiy, A.; Nisi, S.; Pivato, G.; Schönert, S.; Tarka, M.; von Sturm, K.

    2013-04-01

    The GERDA experiment searches for the neutrinoless double beta (0νββ) decay of 76Ge using high-purity germanium detectors made of material enriched in 76Ge. For Phase II of the experiment a sensitivity for the half life T1/20ν ~ 2·1026 yr is envisioned. Modified Broad Energy Germanium detectors (BEGe) with thick n+ electrodes provide the capability to efficiently identify and reject background events, while keeping a large acceptance for the 0νββ-decay signal through novel pulse-shape discrimination (PSD) techniques. The viability of producing thick-window BEGe-type detectors for the GERDA experiment is demonstrated by testing all the production steps from the procurement of isotopically modified germanium up to working BEGe detectors. Comprehensive testing of the spectroscopic as well as PSD performance of the GERDA Phase II prototype BEGe detectors proved that the properties of these detectors are identical to those produced previously from natural germanium material following the standard production line of the manufacturer. Furthermore, the production of BEGe detectors from a limited amount of isotopically modified germanium served to optimize the production, in order to maximize the overall detector mass yield. The results of this test campaign provided direct input for the subsequent production of the enriched germanium detectors.

  14. The GERDA experiment: results and perspectives

    NASA Astrophysics Data System (ADS)

    Macolino, Carla; Gerda Collaboration

    2014-11-01

    The Germanium Detector Array, GERDA, at Laboratori Nazionali del Gran Sasso (Italy), is designed to search for Majorana neutrinos via neutrinoless double beta (0νββ) decay of 76Ge. GERDA completed the Phase I in 2013, after an exposure of 21.6 kg·yr and with a background of about 0.01 cts/(keVkgyr): no signal was found and a limit on the half-life of T0ν1/2 > 2.1 · 1025 yr (90% C.L.) was established. The previous claim of 0νββ observation for 76Ge is strongly disfavoured in a model independent way. The commission for GERDA Phase II is currently ongoing and about 20 kg of additional enriched Ge diodes will be deployed. Pulse- shape analysis, together with the liquid argon instrumentation will allow to reach a background level one order of magnitude lower than in Phase I. In this paper the measurement of the half-life of 0νββ decay from GERDA Phase I and the expected sensitivity for Phase II are discussed.

  15. Dead Layer Measurement in P-type Point Contact Germanium Detectors for the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Elia, Sophia; Majorana Collaboration

    2015-10-01

    The Majorana Demonstrator will search for the neutrinoless double beta decay (0 νββ) of the isotope 76Ge. In anticipation of the future large-scale experiments, its goal is to demonstrate a path forward to a background rate of one cnt/(ROI-t-y) in a 4 keV region around the Q-value of the 76Ge 0 νββ . The Majorana Demonstrator consists of an array of high purity germanium detectors arranged in strings. Before installation in the cryostat, each string has been characterized. A vertical scan along the string (Z-scan) using radioactive sources is performed to measure the dead layer of each detector while an azimuthal scan is taken to measure the orientation of the crystal axes, useful for axion physics. Understanding the dead layer of the crystals is crucial to precisely determine the effective mass of the detectors. This poster presents Z-scan measurements and data analysis. The dead layer determination obtained through detailed comparison of simulation and data will be discussed.

  16. The Majorana Low-noise Low-background Front-end Electronics

    NASA Astrophysics Data System (ADS)

    Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    The MAJORANA DEMONSTRATOR will search for the neutrinoless double beta decay (ββ(0ν)) of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. In view of the next generation of tonne-scale germanium-based ββ(0ν)-decay searches, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ(0ν)-decay. Such a requirement on the background level significantly constrains the design of the readout electronics, which is further driven by noise and energy resolution performances. We present here the low-noise low- background front-end electronics developed for the low-capacitance p-type point contact (P-PC) germanium detectors of the MAJORANA DEMONSTRATOR. This resistive-feedback front-end, specifically designed to have low mass, is fabricated on a radioassayed fused-silica substrate where the feedback resistor consists of a sputtered thin film of high purity amorphous germanium and the feedback capacitor is based on the capacitance between gold conductive traces.

  17. Status of the GERDA Phase II upgrade

    NASA Astrophysics Data System (ADS)

    Wagner, Victoria

    2016-06-01

    The GERDA experiment is designed to search for neutrinoless double beta (0νββ) decay of 76Ge. In Phase I of the experiment a background index of 10-2 cts/(keV.kg.yr) was reached. A lower limit on the half-life of the 0νββ decay of 76Ge was set to 2.1.1025 yr (at 90% C.L.). The aim of Phase II is to reach a sensitivity of the half-life of about 1026 yr. To increase the exposure thirty new Broad Energy Germanium (BEGe) detectors have been produced. These detectors are distinct for their improved energy resolution and enhanced pulse shape discrimination of signal from background events. Further background reduction will be reached by a light instrumentation to read out argon scintillation light. In April 2015 the light instrumentation together with eight BEGe detectors has been successfully deployed in the GERDA cryostat. In a commissioning run it was shown that two of the major background components, external γ-rays from 214Bi and 208Tl decays, were suppressed up to two orders of magnitude. We are confident to reach a background index of 10-3 cts/(keV.kg.yr) which is the design goal for GERDA Phase II.

  18. The Majorana low background low noise front-end electronics

    NASA Astrophysics Data System (ADS)

    Abgrall, Nicolas

    2014-03-01

    The Majorana Demonstrator will search for the neutrinoless double beta decay (ββ (0 ν)) of 76Ge with a mixed array of enriched and natural germanium detectors. In view of the next generation of tonne-scale germanium-based ββ (0 ν)-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the experiment is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ (0 ν)-decay. Such a requirement on the background level in conjunction with the best possible energy resolution to increase the signal-to-noise ratio in the ROI significantly constrain the readout electronics. We present here the low background low noise front-end electronics developed for the low-capacitance P-type point-contact (PPC) germanium detectors of the Majorana Demonstrator. This resistive-feedback front-end, specifically designed to have low mass, is fabricated on a radioactivity-assayed fused silica substrate where the feedback resistor consists of a sputtered thin film of high purity amorphous germanium and the feedback capacitor is based on the stray capacitance between circuit Au traces.

  19. Low Background Signal Readout Electronics for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Guinn, I.; Abgrall, N.; Arnquist, Isaac J.; Avignone, Frank T.; Baldenegro-Barrera, C. X.; Barabash, Alexander S.; Bertrand, F.; Bradley, A. W.; Brudanin, V.; Busch, Matthew; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, C. D.; Cuesta, C.; Detwiler, Jason A.; Efremenko, Yuri; Ejiri, H.; Elliott, Steven R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Jasinski, B. R.; Keeter, K.; Kidd, M. F.; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, John L.; O'Shaughnessy, C.; Poon, Alan; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, Anne-Marie; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, Chang-Hong; Yumatov, Vladimir; Zhitnikov, I.

    2015-03-18

    The Majorana Demonstrator (MJD)[1] is an array of p-type point contact (PPC) high purity Germanium (HPGe) detectors intended to search for neutrinoless double beta decay (0vBB decay) in 76Ge. MJD will consist of 40 kg of detectors, 30 kg of which will be isotopically enriched to 87% 76Ge. The array will consist of 14 strings of four or ve detectors placed in two separate cryostats. One of the main goals of the experiment is to demonstrate the feasibility of building a tonne-scale array of detectors to search for 0vBB decay with a much higher sensitivity. This involves acheiving backgrounds in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the BB decay of less than 1 count/ROI-t-y. Because many backgrounds will not directly scale with detector mass, the specific background goal of MJD is less than 3 counts/ROI-t-y.

  20. A search for the radiative neutrinoless double-electron capture of 58Ni

    NASA Astrophysics Data System (ADS)

    Lehnert, B.; Degering, D.; Frotscher, A.; Michel, T.; Zuber, K.

    2016-06-01

    A search for the radiative neutrinoless double-electron capture with single γ-ray emission has been performed in 58Ni. Gamma radiation from a 7286 {{g}} nickel sample in natural isotope composition was measured for 58.3 {{d}} with an ultra-low background HPGe detector in the Felsenkeller underground laboratory in Dresden, Germany. A new lower half-life limit of 2.1× {10}21 yr (90% CL) was obtained for this decay mode. This half-life limit is two orders of magnitude higher than the existing limit for 58Ni and among the best half-life limits for neutrinoless double-electron capture decays.

  1. HEROICA: an underground facility for the fast screening of germanium detectors

    NASA Astrophysics Data System (ADS)

    Andreotti, E.; Garfagnini, A.; Maneschg, W.; Barros, N.; Benato, G.; Brugnera, R.; Costa, F.; Falkenstein, R.; Guthikonda, K. K.; Hegai, A.; Hemmer, S.; Hult, M.; Jänner, K.; Kihm, T.; Lehnert, B.; Liao, H.; Lubashevskiy, A.; Lutter, G.; Marissens, G.; Modenese, L.; Pandola, L.; Reissfelder, M.; Sada, C.; Salathe, M.; Schmitt, C.; Schulz, O.; Schwingenheuer, B.; Turcato, M.; Ur, C.; von Sturm, K.; Wagner, V.; Westermann, J.

    2013-06-01

    HEROICA (Hades Experimental Research Of Intrinsic Crystal Appliances) is an infrastructure to characterize germanium detectors and has been designed and constructed at the HADES Underground Research Laboratory, located in Mol (Belgium). Thanks to the 223 m overburden of clay and sand, the muon flux is lowered by four orders of magnitude. This natural shield minimizes the exposure of radio-pure germanium material to cosmic radiation resulting in a significant suppression of cosmogenic activation in the germanium detectors. The project has been strongly motivated by a special production of germanium detectors for the GERDA experiment. GERDA, currently collecting data at the Laboratori Nazionali del Gran Sasso of INFN, is searching for the neutrinoless double beta decay of 76Ge. In the near future, GERDA will increase its mass and sensitivity by adding new Broad Energy Germanium (BEGe) detectors. The production of the BEGe detectors is done at Canberra in Olen (Belgium), located about 30 km from the underground test site. Therefore, HADES is used both for storage of the crystals over night, during diode production, and for the characterization measurements. A full quality control chain has been setup and tested on the first seven prototype detectors delivered by the manufacturer at the beginning of 2012. The screening capabilities demonstrate that the installed setup fulfills a fast and complete set of measurements on the diodes and it can be seen as a general test facility for the fast screening of high purity germanium detectors. The results are of major importance for a future massive production and characterization chain of germanium diodes foreseen for a possible next generation 1-tonne double beta decay experiment with 76Ge.

  2. Double resonant enhancement in the neutrinoless double-electron capture of 190Pt

    NASA Astrophysics Data System (ADS)

    Eibach, M.; Bollen, G.; Gulyuz, K.; Izzo, C.; Redshaw, M.; Ringle, R.; Sandler, R.; Valverde, A. A.

    2016-07-01

    Background: The observation of neutrinoless double-β transitions would indicate physics beyond the standard model as the lepton number conservation is violated. For a complete degeneracy in the energy of the initial and final states, the neutrinoless double-electron capture is resonantly enhanced. This shortens the half-life to similar orders of magnitude as the neutrinoless double-β decay and expands the set of nuclei for the search of neutrinoless double-β transitions as the observation of either process would be equally likely. Purpose: To clearly identify transitions that are resonantly enhanced, among other parameters the total energy of the decay, Qɛ ɛ, needs to be measured very precisely. Of the 12 initially identified candidates, the last remaining decay without a precise Qɛ ɛ was 190Pt(0 ν ɛ ɛ )190Os . Method: The Qɛ ɛ value was determined with the Penning trap mass spectrometer LEBIT by measuring the ratio of the cyclotron frequencies of +190Pt and +190Os in a 9.4-T superconducting magnet. Result: The Qɛ ɛ value was determined to be 1401.57(47) keV with an uncertainty reduction of an order of magnitude compared to its previously known value. The absolute value is shifted by 17.17(623) keV relative to the previously accepted one. Furthermore, the mass value of 190Pt was found to be shifted by more than three standard deviations. In addition we improved the mass values for Os,190186 and 194Pt. Conclusion: Transitions to the two nuclear excited states of 190Os with 1326.9(5) and 1387.00(2) keV energy were identified to be resonantly enhanced within a 1 σ uncertainty. The significantly reduced uncertainty of Qɛ ɛ confirmed the potential for a resonantly enhanced transition.

  3. Overview and Status of the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Mertens, Susanne

    2014-09-01

    A unique way to explore the nature of the neutrino is the search for neutrinoless double beta decay (ββ (0 ν)-decay). Observation of ββ (0 ν)-decay would decisively prove that neutrinos are Majorana particles and that lepton number is violated. The MAJORANA DEMONSTRATOR will perform a search for ββ (0 ν)-decay in 76Ge. The experiment is currently under construction at the Sanford Underground Laboratory in South Dakota, USA. It will use an array of 40 kg of HPGe detectors, up to 30 kg of which will be enriched to 86% in 76Ge, surrounded by passive and active shielding. The major goal is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ (0 ν)-decay. This is required for the next generation of tonne-scale germanium-based ββ (0 ν)-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region. This talk will give a general overview of the experiment and its current status. A unique way to explore the nature of the neutrino is the search for neutrinoless double beta decay (ββ (0 ν)-decay). Observation of ββ (0 ν)-decay would decisively prove that neutrinos are Majorana particles and that lepton number is violated. The MAJORANA DEMONSTRATOR will perform a search for ββ (0 ν)-decay in 76Ge. The experiment is currently under construction at the Sanford Underground Laboratory in South Dakota, USA. It will use an array of 40 kg of HPGe detectors, up to 30 kg of which will be enriched to 86% in 76Ge, surrounded by passive and active shielding. The major goal is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ (0 ν)-decay. This is required for the next generation of tonne-scale germanium-based ββ (0 ν)-decay searches that will probe the neutrino mass scale in the inverted

  4. Search for the neutrinoless muon decay. mu. /sup +/. -->. e/sup +/. gamma

    SciTech Connect

    Wilson, S.L.

    1985-07-01

    Separate muon, electron, and tau numbers are conserved in the minimal standard model of electroweak interactions with massless neutrinos. However, in many extensions to the standard model, separate lepton numbers are not expected to be conserved quantities. A new search for muon number non-conserving processes has been undertaken at the Los Alamos Meson Physics Facility (LAMPF), specifically to look for three neutrinoless decay modes of the muon. The search for the decay of a muon to an electron and a photon is discussed here. A new detector facility, located in the LAMPF stopped muon channel, was developed for this experiment. This Crystal Box detector consists of a cylindrical drift chamber surrounded by a plastic scintillator hodoscope and a large solid angle, modularized, NaI(Tl) calorimeter. The apparatus measures the trajectories, relative timing, and energies of charged particles and photons from the decays of positive muons stopped in a central target. The assembly and calibration of the detector are described, and the procedure for taking data is discussed. The sample of 1.3 million candidate events, from the first data run of the Crystal Box, was analyzed using a maximum-likelihood method. The upper limit on the branching ratio, relative to normal muon decay, for a muon decaying to an electron and a photon is found to be consistent with previous measurements. With 90% confidence, the branching ratio for this neutrinoless decay is observed to be less than 2.8 x 10/sup 10/.

  5. Experimental studies of nuclear matrix elements for neutrino-less ββ decays

    SciTech Connect

    Ejiri, H.

    2013-12-30

    Nuclear matrix elements M{sup 0ν} for neutrino less double beta decays (0νββ) are crucial for neutrino studies in 0νββ experiments. The neutrino mass to be studied is sensitive to M{sup 0ν}, while theoretical calculations for M{sup 0ν} are hard. Thus experimental studies of nuclear structures and single β matrix elements M{sub β} associated with 0νββ are useful to confirm and help the theoretical calculations. This reports briefly experimental methods and recent charge exchange reaction studies for M{sub β}. The single β elements for M{sup ±}(2{sup −}) associated with M{sup 0ν}(2{sup −}), which is the major component of M{sup 0ν}, are found to be reduced (quenched) much by the spin isospin correlation and the nuclear medium (non-nucleonic isobar) effect. The present result suggests that the spin isospin components of M{sup 0ν} is fairly reduced (quenched)

  6. Probing the nuclides {sup 102}Pd, {sup 106}Cd, and {sup 144}Sm for resonant neutrinoless double-electron capture

    SciTech Connect

    Goncharov, M.; Blaum, K.; Eliseev, S.; Block, M.; Herfurth, F.; Minaya Ramirez, E.; Droese, C.; Schweikhard, L.; Novikov, Yu. N.; Zuber, K.

    2011-08-15

    The Q values for double-electron capture in {sup 102}Pd, {sup 106}Cd, and {sup 144}Sm have been measured by Penning-trap mass spectrometry. The results exclude at present all three nuclides from the list of suitable candidates for a search for resonant neutrinoless double-electron capture.

  7. Pulse shape discrimination for Gerda Phase I data

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2013-10-01

    The Gerda experiment located at the Laboratori Nazionali del Gran Sasso of INFN searches for neutrinoless double beta (0 νββ) decay of 76Ge using germanium diodes as source and detector. In Phase I of the experiment eight semi-coaxial and five BEGe type detectors have been deployed. The latter type is used in this field of research for the first time. All detectors are made from material with enriched 76Ge fraction. The experimental sensitivity can be improved by analyzing the pulse shape of the detector signals with the aim to reject background events. This paper documents the algorithms developed before the data of Phase I were unblinded. The double escape peak (DEP) and Compton edge events of 2.615 MeV γ rays from 208Tl decays as well as two-neutrino double beta (2 νββ) decays of 76Ge are used as proxies for 0 νββ decay. For BEGe detectors the chosen selection is based on a single pulse shape parameter. It accepts 0.92±0.02 of signal-like events while about 80 % of the background events at Q ββ =2039 keV are rejected. For semi-coaxial detectors three analyses are developed. The one based on an artificial neural network is used for the search of 0 νββ decay. It retains 90 % of DEP events and rejects about half of the events around Q ββ . The 2 νββ events have an efficiency of 0.85±0.02 and the one for 0 νββ decays is estimated to be . A second analysis uses a likelihood approach trained on Compton edge events. The third approach uses two pulse shape parameters. The latter two methods confirm the classification of the neural network since about 90 % of the data events rejected by the neural network are also removed by both of them. In general, the selection efficiency extracted from DEP events agrees well with those determined from Compton edge events or from 2 νββ decays.

  8. The trigger card system for the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Thompson, William; Anderson, John; Howe, Mark; Meijer, Sam; Wilkerson, John; Majorana Collaboration

    2014-09-01

    The aim of the MAJORANA DEMONSTRATOR is to demonstrate the feasibility of providing low enough background levels to search for neutrinoless double-beta decay (0 νββ) in an array of germanium detectors enriched to 87% in 76Ge. Currently, it is unknown if this decay process occurs; however, observation of such a decay process would show that lepton number is violated, confirm that neutrinos are Majorana particles, and yield information on the absolute mass scale of the neutrino. With current experimental results indicating a half-life greater than 2 x 1025 years for this decay, the minimization of background events is of critical importance. Utilizing time correlation, coincidence testing is able to reject multi-detector events that may otherwise be mistaken for 0 νββ when viewed independently. Here, we present both the hardware and software of the trigger card system, which provides a common clock to all digitizers and the muon veto system, thereby enabling the rejection of background events through coincidence testing. Current experimental results demonstrate the accuracy of the distributed clock to be within two clock pulses (20 ns) across all system components. A test system is used to validate the data acquisition system. The aim of the MAJORANA DEMONSTRATOR is to demonstrate the feasibility of providing low enough background levels to search for neutrinoless double-beta decay (0 νββ) in an array of germanium detectors enriched to 87% in 76Ge. Currently, it is unknown if this decay process occurs; however, observation of such a decay process would show that lepton number is violated, confirm that neutrinos are Majorana particles, and yield information on the absolute mass scale of the neutrino. With current experimental results indicating a half-life greater than 2 x 1025 years for this decay, the minimization of background events is of critical importance. Utilizing time correlation, coincidence testing is able to reject multi-detector events that may

  9. Neutrinoless universe.

    PubMed

    Beacom, John F; Bell, Nicole F; Dodelson, Scott

    2004-09-17

    We consider the consequences for the relic neutrino abundance if extra neutrino interactions are allowed, e.g., the coupling of neutrinos to a light (compared to m(nu)) boson. For a wide range of couplings not excluded by other considerations, the relic neutrinos would annihilate to bosons at late times and thus make a negligible contribution to the matter density today. This mechanism evades the neutrino mass limits arising from large scale structure. PMID:15447250

  10. Examination of the possible enhancement of neutrinoless double-electron capture in 78Kr

    NASA Astrophysics Data System (ADS)

    Bustabad, S.; Bollen, G.; Brodeur, M.; Lincoln, D. L.; Novario, S. J.; Redshaw, M.; Ringle, R.; Schwarz, S.

    2013-09-01

    Penning-trap mass spectrometry was used at the Low-Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory (NSCL) to investigate 78Kr, a candidate for resonantly enhanced neutrinoless double-electron capture (0νECEC). The newly determined Q value of 2847.75 (27) keV is 1.4 keV greater than the value from the most recent atomic mass evaluation [Chin. Phys. C1674-113710.1088/1674-1137/36/12/003 36, 1603 (2012)], a change of two sigma, and the uncertainty has been reduced by a factor of three. The change in the Q value shifts allowed 0νECEC in 78Kr further from resonant enhancement. With the improved determination of the Q value, all known excited states can now be confidently excluded from possible 78Se candidates that could lead to resonantly enhanced 0νECEC.

  11. Uncertainties in nuclear transition matrix elements of neutrinoless ββ decay

    SciTech Connect

    Rath, P. K.

    2013-12-30

    To estimate the uncertainties associated with the nuclear transition matrix elements M{sup (K)} (K=0ν/0N) for the 0{sup +} → 0{sup +} transitions of electron and positron emitting modes of the neutrinoless ββ decay, a statistical analysis has been performed by calculating sets of eight (twelve) different nuclear transition matrix elements M{sup (K)} in the PHFB model by employing four different parameterizations of a Hamiltonian with pairing plus multipolar effective two-body interaction and two (three) different parameterizations of Jastrow short range correlations. The averages in conjunction with their standard deviations provide an estimate of the uncertainties associated the nuclear transition matrix elements M{sup (K)} calculated within the PHFB model, the maximum of which turn out to be 13% and 19% owing to the exchange of light and heavy Majorana neutrinos, respectively.

  12. TeV lepton number violation: From neutrinoless double-β decay to the LHC

    NASA Astrophysics Data System (ADS)

    Peng, Tao; Ramsey-Musolf, Michael J.; Winslow, Peter

    2016-05-01

    We analyze the sensitivity of next-generation tonne-scale neutrinoless double-β decay (0 ν β β ) experiments and searches for same-sign di-electrons plus jets at the Large Hadron Collider to TeV scale lepton number violating interactions. Taking into account previously unaccounted for physics and detector backgrounds at the LHC, renormalization group evolution, and long-range contributions to 0 ν β β nuclear matrix elements, we find that the reach of tonne-scale 0 ν β β generally exceeds that of the LHC for a class of simplified models. However, for a range of heavy particle masses near the TeV scale, the high luminosity LHC and tonne-scale 0 ν β β may provide complementary probes.

  13. Degeneracy at 1871 keV in {sup 112}Cd and implications for neutrinoless double electron capture

    SciTech Connect

    Green, K. L.; Garrett, P. E.; Demand, G. A.; Grinyer, G. F.; Leach, K. G.; Phillips, A. A.; Schumaker, M. A.; Svensson, C. E.; Wong, J.; Austin, R. A. E.; Colosimo, S.; Ball, G. C.; Bandyopadhyay, D. S.; Hackman, G.; Morton, A. C.; Pearson, C. J.; Cross, D.; Kulp, W. D.; Wood, J. L.; Yates, S. W.

    2009-09-15

    High-statistics {beta}-decay measurements of {sup 112}Ag and {sup 112}In were performed to study the structure of the {sup 112}Cd nucleus. The precise energies of the doublet of levels at 1871 keV, for which the 0{sup +} member has been suggested as a possible daughter state following neutrinoless double electron capture of {sup 112}Sn, were determined to be 1871.137(72) keV (0{sub 4}{sup +} level) and 1870.743(54) keV (4{sub 2}{sup +} level). The nature of the 0{sub 4}{sup +} level, required for the calculation of the nuclear matrix element that would be needed to extract a neutrino mass from neutrinoless double electron capture to this state, is suggested to be of intruder origin.

  14. Design and performance of the Majorana low-noise low-background front-end electronics

    NASA Astrophysics Data System (ADS)

    Abgrall, Nicolas; Majorana Collaboration

    2014-09-01

    The Majorana Demonstrator will search for the neutrinoless double beta decay (ββ (0 ν)) of the isotope 76Ge. In view of the next generation of tonne-scale germanium-based ββ (0 ν)-decay searches, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ (0 ν)-decay. Such a requirement on the background level significantly constrains the design of the readout electronics which is further driven by noise performances. We present here the low-noise low-background front-end electronics developed for the low-capacitance P-type point-contact (PPC) germanium detectors of the Majorana Demonstrator. This resistive-feedback front-end, specifically designed to have low mass, is fabricated on a radioactivity-assayed fused silica substrate where the feedback resistor consists of a sputtered thin film of high purity amorphous germanium and the feedback capacitor is based on the capacitance between circuit Au traces. Performance studies of the front-end and associated back-end electronics in single and multi-detector systems, as well as on-site performances are reported. The Majorana Demonstrator will search for the neutrinoless double beta decay (ββ (0 ν)) of the isotope 76Ge. In view of the next generation of tonne-scale germanium-based ββ (0 ν)-decay searches, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039-keV Q-value of the 76Ge ββ (0 ν)-decay. Such a requirement on the background level significantly constrains the design of the readout electronics which is further driven by noise performances. We present here the low-noise low-background front-end electronics developed for the low-capacitance P-type point-contact (PPC) germanium detectors of the Majorana

  15. P-type point contact germanium detectors and their application in rare-event searches

    NASA Astrophysics Data System (ADS)

    Giovanetti, Graham Kurt

    In the last two decades, experimental results from the direct detection of solar, reactor, and atmospheric neutrinos have provided convincing evidence that neutrinos have mass, the first definitive evidence of physics beyond the Standard Model. The existence of massive neutrinos opens many questions about the neutrino's intrinsic properties, including the absolute mass, the relative hierarchy of the neutrino mass states, and the Majorana or Dirac nature of the neutrino. The Majorana Demonstrator is an array of p-type point contact (PPC) high purity germanium detectors that will search for the neutrinoless double-beta decay (0nubetabeta) of 76Ge, a process that can only occur if the neutrino is a Majorana particle. PPC detectors have several characteristics that make them well suited for a 76Ge 0nubetabeta search, including sub-keV energy thresholds that allow for background rejection based on low-energy x-ray tagging. This feature makes the Majorana Demonstrator sensitive to signals that might be present from processes that are not in the current Standard Model of particle physics. The Majorana Low-background Broad Energy Germanium Detector at KURF (MALBEK) is a PPC detector operated at the Kimballton Underground Research Facility (KURF) in Ripplemead, VA. MALBEK was used to test the stability and performance of PPC detectors and study sources of background near the detector energy threshold. It was found that the dominant background below 1 keV in MALBEK data is due to slow surface events, a class of signals originating from interactions that occur near the detector surface. Techniques were developed for identifying surface events and simulating their formation and distribution. These techniques were then applied to 89.5 kg-d of data and searches were performed for signals from weakly interacting massive particles (WIMPs), solar axions, and Pauli exclusion principle violating electron transitions. No evidence of a signal was found. These results are presented in

  16. Results of a search for neutrinoless double-β decay using the COBRA demonstrator

    NASA Astrophysics Data System (ADS)

    Ebert, Joachim; Fritts, M.; Gehre, Daniel; Gößling, Claus; Hagner, Caren; Heidrich, Nadine; Klingenberg, Reiner; Kröninger, Kevin; Nitsch, Christian; Oldorf, Christian; Quante, Thomas; Rajek, Silke; Rebber, Henning; Rohatsch, Katja; Tebrügge, Jan; Temminghoff, Robert; Theinert, Robert; Timm, Jan; Wonsak, Björn; Zatschler, Stefan; Zuber, Kai; Cobra Collaboration

    2016-08-01

    Neutrinoless double-β decay (0 ν β β decay) is a hypothetical process that can occur if the neutrino is its own antiparticle. The COBRA Collaboration operates a demonstrator to search for these decays at the Laboratori Nazionali del Gran Sasso in Italy using CdZnTe semiconductor detectors. The exposure of 234.7 kg d considered in this analysis was collected between September 2011 and February 2015. The analysis focuses on the decay of the nuclides 114Cd,128Te,70Zn,130Te, and 116Cd. A Bayesian analysis is performed to estimate the signal strength of 0 ν β β decay. No signal is observed for any of these nuclides. Therefore, the following half-life limits at 90% credibility are set: T1/2 0 ν>1.6 ×1021yr (114Cd),T1/2 0 ν>1.9 ×1021yr (128Te),T1/2 0 ν>6.8 ×1018yr (70Zn),T1/2 0 ν>6.1 ×1021yr (130Te), and T1/2 0 ν>1.1 ×1021yr (116Cd).

  17. Neutrino propagation in nuclear medium and neutrinoless double-β decay.

    PubMed

    Kovalenko, S; Krivoruchenko, M I; Simkovic, F

    2014-04-11

    We discuss a novel effect in neutrinoless double-β (0νββ) decay related with the fact that its underlying mechanisms take place in the nuclear matter environment. We study the neutrino exchange mechanism and demonstrate the possible impact of nuclear medium via lepton-number-violating (LNV) four-fermion interactions of neutrinos with quarks from a decaying nucleus. The net effect of these interactions is the generation of an effective in-medium Majorana neutrino mass matrix. The enhanced rate of the 0νββ decay can lead to the apparent incompatibility of observations of the 0νββ decay with the value of the neutrino mass determined or restricted by the β-decay and cosmological data. The effective neutrino masses and mixing are calculated for the complete set of the relevant four-fermion neutrino-quark operators. Using experimental data on the 0νββ decay in combination with the β-decay and cosmological data, we evaluate the characteristic scales of these operators: ΛLNV≥2.4  TeV. PMID:24765948

  18. Status of the Majorana Demonstrator experiment

    NASA Astrophysics Data System (ADS)

    Martin, R. D.; Abgrall, N.; Aguayo, E.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Mertens, S.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G., II; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    2014-06-01

    The Majorana Demonstrator neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.

  19. Status of the MAJORANA DEMONSTRATOR experiment

    SciTech Connect

    Martin, R. D.; Abgrall, N.; Aguayo, Estanislao; Avignone, F. T.; Barabash, Alexander S.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, P. J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, Mark D.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Soin, Aleksandr; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-07-08

    The MAJORANA DEMONSTRATOR neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.

  20. Status of the MAJORANA DEMONSTRATOR experiment

    SciTech Connect

    Martin, R. D.; Abgrall, N.; Chan, Y-D.; Hegai, A.; Mertens, S.; Poon, A. W. P.; Vetter, K.; Aguayo, E.; Fast, J. E.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Overman, N. R.; Soin, A.; Avignone III, F. T.; Barabash, A. S.; Konovalov, S. I.; Yumatov, V.; Bertrand, F. E.; and others

    2014-06-24

    The MAJORANA DEMONSTRATOR neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.

  1. GERDA phase II detectors: Behind the production and characterisation at low background conditions

    NASA Astrophysics Data System (ADS)

    Maneschg, Werner; Gerda Collaboration

    2013-08-01

    The low background GERmanium Detector Array (GERDA) at Laboratori Nazionali del Gran Sasso (LNGS) is designed to search for the rare neutrinoless double beta decay (0νββ) in 76Ge. Bare germanium diodes are operated in liquid argon which is used as coolant, as passive and soon active as well shield against external radiation. Currently, Phase I of the experiment is running using ˜15 kg of co-axial High Purity Germanium diodes. In order to increase the sensitivity of the experiment 30 Broad Energy Germanium (BEGe) diodes will be added within 2013. This presentation reviews the production chain of the new BEGe detectors from isotopic enrichment to diode production and testing. As demonstrated all steps were carefully planned in order to minimize the exposure of the enriched germanium to cosmic radiation. Following this premise, acceptance and characterisation measurement of the newly produced diodes have been performed within the HEROICA project in the Belgian underground laboratory HADES close to the diode manufacturer. The test program and the results from a subset of the recently terminated GERDA Phase II BEGe survey will be presented.

  2. ICP MS selection of radiopure materials for the GERDA experiment

    NASA Astrophysics Data System (ADS)

    di Vacri, M. L.; Nisi, S.; Cattadori, C.; Janicsko, J.; Lubashevskiy, A.; Smolnikov, A.; Walter, M.

    2015-08-01

    The GERDA (GERmanium Detector Array) experiment, located in the Gran Sasso Underground Laboratory (LNGS, Italy) aims to search for neutrinoless double beta (0νββ) decay of the 76Ge isotope. Both an ultra-low radioactivity background environment and active techniques to abate the residual background are required to reach the background index (of 10-3 counts/keV kg y) at the Qββ. In order to veto and suppress those events that partially deposit energy in Ge detectors, the readout of liquid argon (LAr) scintillation light (SL) has been implemented for the second GERDA experimental Phase. A double veto system has been designed and constructed using highly radiopure materials (scintillating fibers, wavelength shifters, polymeric foils, reflective foils). This work describes the study of lead, thorium and uranium ultra-trace content, performed at the LNGS Chemistry Laboratory by High Resolution Mass Spectrometry (HR ICP MS), for the selection of all materials involved in the construction of the veto system

  3. Background rejection of n+ surface events in GERDA Phase II

    NASA Astrophysics Data System (ADS)

    Lehnert, Björn

    2016-05-01

    The GERDA experiment searches for neutrinoless double beta (0vββ) decay in 76Ge using an array of high purity germanium (HPGe) detectors immersed in liquid argon (LAr). Phase II of the experiment uses 30 new broad energy germanium (BEGe) detectors with superior pulse shape discrimination capabilities compared to the previously used semi-coaxial detector design. By far the largest background component for BEGe detectors in GERDA are n+-surface events from 42K β decays which are intrinsic in LAr. The β particles with up to 3.5 MeV can traverse the 0.5 to 0.9 mm thick electrode and deposit energy within the region of interest for the 0vββ decay. However, those events have particular pulse shape features allowing for a strong discrimination. The understanding and simulation of this background, showing a reduction by up to a factor 145 with pulse shape discrimination alone, is presented in this work.

  4. Improvement of the GERDA Ge Detectors Energy Resolution by an Optimized Digital Signal Processing

    NASA Astrophysics Data System (ADS)

    Benato, G.; D'Andrea, V.; Cattadori, C.; Riboldi, S.

    GERDA is a new generation experiment searching for neutrinoless double beta decay of 76Ge, operating at INFN Gran Sasso Laboratories (LNGS) since 2010. Coaxial and Broad Energy Germanium (BEGe) Detectors have been operated in liquid argon (LAr) in GERDA Phase I. In the framework of the second GERDA experimental phase, both the contacting technique, the connection to and the location of the front end readout devices are novel compared to those previously adopted, and several tests have been performed. In this work, starting from considerations on the energy scale stability of the GERDA Phase I calibrations and physics data sets, an optimized pulse filtering method has been developed and applied to the Phase II pilot tests data sets, and to few GERDA Phase I data sets. In this contribution the detector performances in term of energy resolution and time stability are here presented. The improvement of the energy resolution, compared to standard Gaussian shaping adopted for Phase I data analysis, is discussed and related to the optimized noise filtering capability. The result is an energy resolution better than 0.1% at 2.6 MeV for the BEGe detectors operated in the Phase II pilot tests and an improvement of the energy resolution in LAr of about 8% achieved on the GERDA Phase I calibration runs, compared to previous analysis algorithms.

  5. Partial Cross Sections of Neutron-Induced Reactions on nCu at En = 6, 8, 10, 12, 14, and 16 MeV for 0νββ Background Studies

    NASA Astrophysics Data System (ADS)

    Gooden, M. E.; Fallin, B. A.; Finch, S. W.; Kelley, J. H.; Howell, C. R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Stanislav, V.

    2014-05-01

    Partial cross-section measurements of (n,n'γ) reactions on natCu were carried out at TUNL using monoenergetic neutrons at six energies of En = 6, 8, 10, 12, 14, 16 MeV. These studies were performed to provide accurate cross-section data on materials abundant in experimental setups involving HPGe detectors used to search for rare events, like the neutrino-less double-beta decay of 76Ge. Spallation and (α,n) neutrons are expected to cause the largest source of external background in the energy region of interest. At TUNL pulsed neutron beams were produced via the 2H(d,n)3He reaction and the deexcitation γ rays from the reaction natCu(n,xγ) were detected with clover HPGe detectors. Cross-section results for the strongest transtions in 63Cu and 65Cu will be reported, and will compared to model calculations and to data recently obtained at LANL with a white neutron beam.

  6. High voltage testing for the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Dunagan, C.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Fu, Z.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Li, A.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Thompson, A.; Ton, K. T.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.

    2016-07-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA DEMONSTRATOR. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA DEMONSTRATOR was characterized and the micro-discharge effects during the MAJORANA DEMONSTRATOR commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  7. Conversion of experimental half-life to effective electron neutrino mass in 0nubetabeta decay

    SciTech Connect

    Smolnikov, Anatoly; Grabmayr, Peter

    2010-02-15

    The Germanium Detector Array (GERDA) collaboration will be searching for neutrinoless double beta decay of {sup 76}Ge. As a result it will measure the half-life T{sub 1/2} of this rare process; or at least a new value for the lower limit for T{sub 1/2} will be derived. The sensitivity of the GERDA experiment on the effective electron neutrino mass depends on the theoretical value for the nuclear matrix element M and the kinematical phase space factor G.In this Brief Report we focus on existing difficulties in applying the dimensionless values of M calculated by various theoretical groups, which use different methods and parametrizations. The implicit radius dependencies in M and G are discussed. Resulting values of the neutrino mass are tabulated for various representative half-lives T{sub 1/2} representing the sensitivity of the various phases of the GERDA experiment.

  8. Validation of Pulse Shape Simulation for Ge detectors in the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Shanks, Benjamin; Majorana Collaboration

    2015-04-01

    The MAJORANA DEMONSTRATOR expects to begin searching for neutrinoless double beta decay using 76 Ge-enriched detectors in 2015. The DEMONSTRATOR high purity germanium (HPGe) detectors are built in the p-type point contact (PPC) geometry. The electrode of a PPC detector is small and shallow, resulting in low intrinsic capacitance and bulk field strengths compared to the traditional coaxial HPGe configuration. These characteristics allow for discrimination of signal event candidates from background using pulse shape analysis (PSA). In order to fully understand the systematics and efficiencies of PSA cuts, the MAJORANA collaboration has developed a software package to simulate signal generation in PPC detectors. This code has been validated by comparing simulated pulses to the pulse shapes generated for given detectors using an external source. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  9. Low background signal readout electronics for the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Guinn, I.; Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Cuesta, C.; Detwiler, J. A.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.

    2015-08-01

    The MAJORANA Collaboration will seek neutrinoless double beta decay (0νββ) in 76Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed with a background goal of < 3 count/ROI-tonne-year, which is expected to scale down to < 1 count/ROI-tonne-year for a tonne-scale experiment. The signal readout electronics, which must be placed in close proximity to the detectors, present a challenge toward reaching this background goal. This talk will discuss the materials and design used to construct signal readout electronics with low enough backgrounds for the MAJORANA DEMONSTRATOR.

  10. Testing new designs for the Majorana Demonstrator's low-mass front-end board

    NASA Astrophysics Data System (ADS)

    Salemi, Chiara; Majorana Collaboration

    2015-10-01

    The Majorana Demonstrator is searching for neutrinoless double-beta decay in 76Ge p-type point contact (PPC) detectors in order to determine if a neutrino is its own antiparticle and to probe the absolute neutrino mass scale. Finding this rare decay would also show that lepton number is not conserved. The search is made possible by the novel high-purity Ge PPC detector technology, which allows a low energy threshold and excellent energy resolution. Rare event searches with such sensitive detectors require extremely low radioactive backgrounds, and the front-end electronics, located inside the shielding, are one of the primary sources of background events in the signal region. For this reason, the front-end board is made to be low-mass and of radio-pure materials. A new design that is being studied could potentially in the future replace the board's fused silica substrate with a copper back plane coated in parylene, two materials whose assay results show low radioactivity. In addition to decreasing the overall radioactivity of the board, the new design reduces the amount of material near the detectors. Preliminary testing shows that the new design also substantially decreases the intrinsic electronic noise of the signal amplification circuitry.

  11. Bayesian signal processing of pulse shapes for background rejection in the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Shanks, Benjamin; Majorana Collaboration

    2015-10-01

    The Majorana Demonstrator uses high purity germanium (HPGe) detectors in the p-type point contact (PPC) geometry to search for neutrinoless double-beta decay (0 νββ) in 76Ge. Due to the unique electric potential created within the PPC geometry, the detailed pulse shape depends on the number of energy depositions contained within a given event. Pulse shape analysis (PSA) techniques can be used to estimate the number of separate depositions which combine to form a single pulse. This information can be used to discriminate between 0 νββ candidate events, which deposit energy at a single detector site, and gamma ray background, which can scatter and deposit energy in multiple locations. The problem of determining whether a pulse is single- or multi-site is well suited to Bayesian classifiers. Once trained via supervised machine learning, these algorithms can perform nonlinear cuts against multi-site events using the estimated probability function as a discriminator. The Bayesian approach can also be naturally extended to incorporate a model of the physical process responsible for signal generation within the detector. Presented here is an overview of the Bayesian classifier developed for use on the Demonstrator. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  12. Updated constraints on the light-neutrino exchange mechanisms of the 0νββ-decay

    SciTech Connect

    Štefánik, Dušan; Dvornický, Rastislav; Šimkovic, Fedor

    2015-10-28

    The neutrinoless double-beta (0νββ) decay associated with light neutrino exchange mechanisms, which are due to both left-handed V-A and right-handed V+A leptonic and hadronic currents, is discussed by using the recent progress achieved by the GERDA, EXO and KamlandZen experiments. The upper limits for effective neutrino mass m{sub ββ} and the parameters 〈λ〉 and 〈η〉 characterizing the right handed current mechanisms are deduced from the data on the 0νββ-decay of {sup 76}Ge and {sup 136}Xe using nuclear matrix elements calculated within the nuclear shell model and quasiparticle random phase approximation and phase-space factors calculated with exact Dirac wave functions with finite nuclear size and electron screening. The careful analysis of upper constraints on effective lepton number violating parameters assumes a competition of the above mechanisms and arbitrary values of involved CP violating phases.

  13. Germanium Detector Crystal Axis Orientation for the MAJORANA Demonstrator

    NASA Astrophysics Data System (ADS)

    Letourneau, Hannah

    2013-10-01

    The MAJORANA Demonstrator, currently being constructed at Sanford Underground Research Facility in Lead, South Dakota, is an array of germanium detectors which will be used to search for neutrinoless double beta decay, which would demonstrate that neutrinos have a Majorana mass term and lepton number is not conserved. An important characteristic of semiconductor detectors is the crystal axis orientation, because the propagation of electromagnetic signals is attenuated by the location of the interaction relative to the axis of the crystal. Conventionally, a goniometer is used to position a collimated low energy gamma source in many small increments around the detector to measure the rise time at each position. However, due to physical constraints from the casing of the Demonstrator, a different method must be developed. At the University of Washington this summer, I worked with a 76 Ge point-contact detector. I found the crystal axis orientation first with Americium 241, a lower energy gamma source. Then, I used a higher energy source, Thorium 232, in conjunction with the only a few angular reference points to also calculate rise time. Also, I wrote code to process the data. The success of this method will be evaluated and discussed. NSF

  14. 0{nu}{beta}{beta}-decay nuclear matrix elements with self-consistent short-range correlations

    SciTech Connect

    Simkovic, Fedor; Faessler, Amand; Muether, Herbert; Rodin, Vadim; Stauf, Markus

    2009-05-15

    A self-consistent calculation of nuclear matrix elements of the neutrinoless double-beta decays (0{nu}{beta}{beta}) of {sup 76}Ge, {sup 82}Se, {sup 96}Zr, {sup 100}Mo, {sup 116}Cd, {sup 128}Te, {sup 130}Te, and {sup 136}Xe is presented in the framework of the renormalized quasiparticle random phase approximation (RQRPA) and the standard QRPA. The pairing and residual interactions as well as the two-nucleon short-range correlations are for the first time derived from the same modern realistic nucleon-nucleon potentials, namely, from the charge-dependent Bonn potential (CD-Bonn) and the Argonne V18 potential. In a comparison with the traditional approach of using the Miller-Spencer Jastrow correlations, matrix elements for the 0{nu}{beta}{beta} decay are obtained that are larger in magnitude. We analyze the differences among various two-nucleon correlations including those of the unitary correlation operator method (UCOM) and quantify the uncertainties in the calculated 0{nu}{beta}{beta}-decay matrix elements.

  15. ICP MS selection of radiopure materials for the GERDA experiment

    SciTech Connect

    Di Vacri, M. L.; Nisi, S.; Cattadori, C.; Janicsko, J.; Lubashevskiy, A.; Smolnikov, A.; Walter, M.

    2015-08-17

    The GERDA (GERmanium Detector Array) experiment, located in the Gran Sasso Underground Laboratory (LNGS, Italy) aims to search for neutrinoless double beta (0νββ) decay of the {sup 76}Ge isotope. Both an ultra-low radioactivity background environment and active techniques to abate the residual background are required to reach the background index (of 10{sup −3} counts/keV kg y) at the Q{sub ββ}. In order to veto and suppress those events that partially deposit energy in Ge detectors, the readout of liquid argon (LAr) scintillation light (SL) has been implemented for the second GERDA experimental Phase. A double veto system has been designed and constructed using highly radiopure materials (scintillating fibers, wavelength shifters, polymeric foils, reflective foils). This work describes the study of lead, thorium and uranium ultra-trace content, performed at the LNGS Chemistry Laboratory by High Resolution Mass Spectrometry (HR ICP MS), for the selection of all materials involved in the construction of the veto system.

  16. Cryogenic Supply for the Gerda Experiment

    NASA Astrophysics Data System (ADS)

    Haberstroh, Ch.

    2008-03-01

    In the GERDA experiment (GERmanium Detector Array for the search of neutrinoless double beta decay of 76Ge) germanium diodes are suspended in a superinsulated cryostat filled with 70 m3 of liquid argon. The cold medium is required since the diodes have to be operated at low temperatures, and furthermore for shielding against background radiation. For the same reason the whole experiment will be placed in the underground laboratories in the Gran Sasso mountains, Italy. In order to avoid any detrimental perturbation inside the dewar vessel, the liquid-argon (LAr) inventory in the main tank will be kept in a subcooled state at a working pressure of 0.12 MPa absolute at the surface. At the TU Dresden an appropriate cryogenic arrangement was designed to match these requirements. Liquid nitrogen (LN2) is used as a cooling fluid. Special care was taken to cope with the narrow temperature span between the LAr boiling temperature and triple point. In the proposed solution a subcooler located close to the cryostat neck provides a stable LAr convection inside the main tank. The working pressure is adjusted with a controlled, slightly elevated temperature level at the liquid-vapor interface.

  17. High voltage testing for the Majorana Demonstrator

    DOE PAGESBeta

    Abgrall, N.; Arnquist, I. J.; Avignone, III, F. T.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; et al

    2016-04-04

    The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the Majorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of themore » high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during the Majorana Demonstrator commissioning phase were studied. Furthermore, a stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

  18. The MAJORANA DEMONSTRATOR for 0νββ: Current status and future plans

    DOE PAGESBeta

    Green, M. P.; Abgrall, N.; Aguayo, E.; Avignone, III, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; et al

    2015-01-01

    The Majorana Demonstrator will search for neutrinoless-double-beta decay (0νββ) in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based 0νββ experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the 0νββ region of interest (ROI) of nomore » more than 3 counts in the 0νββ-decay ROI per tonne of target isotope per year (cnts/(ROI-t-y)). The current status of the Demonstrator is discussed, as are plans for its completion.« less

  19. Background Model for the Majorana Demonstrator

    SciTech Connect

    Cuesta, C.; Abgrall, N.; Aguayo, Estanislao; Avignone, Frank T.; Barabash, Alexander S.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Nomachi, Masaharu; Orrell, John L.; O'Shaughnessy, C.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2015-06-01

    The Majorana Collaboration is constructing a prototype system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment to search for neutrinoless double-beta (0v BB) decay in 76Ge. In view of the requirement that the next generation of tonne-scale Ge-based 0vBB-decay experiment be capable of probing the neutrino mass scale in the inverted-hierarchy region, a major goal of theMajorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using Geant4 simulations of the different background components whose purity levels are constrained from radioassay measurements.

  20. Low background signal readout electronics for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Guinn, I.; Buuck, M.; Cuesta, C.; Detwiler, J. A.; Gruszko, J.; Leon, J.; Robertson, R. G. H.; Abgrall, N.; Bradley, A. W.; Chan, Y-D.; Mertens, S.; Poon, A. W. P.; Arnquist, I. J.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Bertrand, F. E.; and others

    2015-08-17

    The MAJORANA Collaboration will seek neutrinoless double beta decay (0νββ) in {sup 76}Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed with a background goal of < 3 count/ROI-tonne-year, which is expected to scale down to < 1 count/ROI-tonne-year for a tonne-scale experiment. The signal readout electronics, which must be placed in close proximity to the detectors, present a challenge toward reaching this background goal. This talk will discuss the materials and design used to construct signal readout electronics with low enough backgrounds for the MAJORANA DEMONSTRATOR.

  1. GERDA phase II detectors: Behind the production and characterisation at low background conditions

    SciTech Connect

    Maneschg, Werner; Collaboration: GERDA Collaboration; and others

    2013-08-08

    The low background GERmanium Detector Array (GERDA) at Laboratori Nazionali del Gran Sasso (LNGS) is designed to search for the rare neutrinoless double beta decay (0νββ) in {sup 76}Ge. Bare germanium diodes are operated in liquid argon which is used as coolant, as passive and soon active as well shield against external radiation. Currently, Phase I of the experiment is running using ∼15 kg of co-axial High Purity Germanium diodes. In order to increase the sensitivity of the experiment 30 Broad Energy Germanium (BEGe) diodes will be added within 2013. This presentation reviews the production chain of the new BEGe detectors from isotopic enrichment to diode production and testing. As demonstrated all steps were carefully planned in order to minimize the exposure of the enriched germanium to cosmic radiation. Following this premise, acceptance and characterisation measurement of the newly produced diodes have been performed within the HEROICA project in the Belgian underground laboratory HADES close to the diode manufacturer. The test program and the results from a subset of the recently terminated GERDA Phase II BEGe survey will be presented.

  2. Design and Operation of Cryogenic Distillation Research Column for Ultra-Low Background Experiments

    NASA Astrophysics Data System (ADS)

    Chiller, Christopher; Alanson Chiller, Angela; Jasinski, Benjamin; Snyder, Nathan; Mei, Dongming

    2013-04-01

    Motivated by isotopically enriched germanium (76Ge and 73Ge) for monocrystalline crystal growth for neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation research column was developed. Without market availability of distillation columns in the temperature range of interest with capabilities necessary for our purposes, we designed, fabricated, tested, refined and operated a two-meter research column for purifying and separating gases in the temperature range from 100-200K. Due to interest in defining stratification, purity and throughput optimization, capillary lines were integrated at four equidistant points along the length of the column such that real-time residual gas analysis could guide the investigation. Interior gas column temperatures were monitored and controlled within 0.1oK accuracy at the top and bottom. Pressures were monitored at the top of the column to four significant figures. Subsequent impurities were measured at partial pressures below 2E-8torr. We report the performance of the column in this paper.

  3. Neutrinoless β β decays to excited 0+ states and the Majorana-neutrino mass

    NASA Astrophysics Data System (ADS)

    Hyvärinen, Juhani; Suhonen, Jouni

    2016-06-01

    The nuclear matrix elements (NMEs) corresponding to the neutrinoless double-β (0 ν β β ) decays to excited 0+ states of major experimental interest are calculated. All these decay transitions are electron emitting (0 ν β-β- decays) and take place in the mass A =76 ,82 ,96 ,100 ,110 ,116 ,124 ,130 ,136 nuclei. This work is an extension of our previous work [Phys. Rev. C 91, 024613 (2015), 10.1103/PhysRevC.91.024613], where 0 ν β β decays to the ground states of the same nuclei were treated. We calculate the NMEs for transitions mediated by both the light (l-NMEs) and the heavy (h-NMEs) Majorana neutrinos. A higher-QRPA (quasiparticle random-phase approximation) framework, the multiple-commutator model, is adopted for the calculations, including a previously omitted contribution to the transitions to two-phonon states. A Bonn G -matrix-based effective nucleon-nucleon interaction is generated by exploiting the recently proposed isoscalar-isovector decomposition of the particle-particle proton-neutron interaction parameter, gpp. All the appropriate short-range correlations, nucleon form factors, and higher-order nucleonic weak currents are included to benchmark our calculations. The relevant nuclear spectroscopy was checked to validate the nuclear models used. The computed l-NMEs and h-NMEs are compared with the available other calculations and the relevance of the new included two-phonon term is discussed. The results are summarized by easy-to-use half-life-Majorana-mass interrelations.

  4. Change of nuclear configurations in the neutrinoless double-β decay of 130Te →130Be and 136Xe136Ba

    NASA Astrophysics Data System (ADS)

    Entwisle, J. P.; Kay, B. P.; Tamii, A.; Adachi, S.; Aoi, N.; Clark, J. A.; Freeman, S. J.; Fujita, H.; Fujita, Y.; Furuno, T.; Hashimoto, T.; Hoffman, C. R.; Ideguchi, E.; Ito, T.; Iwamoto, C.; Kawabata, T.; Liu, B.; Miura, M.; Ong, H. J.; Schiffer, J. P.; Sharp, D. K.; Süsoy, G.; Suzuki, T.; Szwec, S. V.; Takaki, M.; Tsumura, M.; Yamamoto, T.

    2016-06-01

    The change in the configuration of valence protons between the initial and final states in the neutrinoless double-β decay of 130Te → 130Be and of 136Xe136Ba has been determined by measuring the cross sections of the (d ,3He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-β decay in these systems.

  5. Upgrades for GERDA Phase II

    NASA Astrophysics Data System (ADS)

    Heisel, Mark

    2014-09-01

    The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta decay (0 νββ) of 76Ge. It is a process that violates lepton number conservation and is predicted to occur in extensions of the standard model of particle physics. GERDA is located underground in the Gran Sasso National Laboratory (LNGS), Italy. An array of bare high-purity germanium detectors enriched in 76Ge is operated in a cryostat with 64 m3 of liquid argon supplemented by a 3 m thick shield of water. The experiment aims at exploring the 0 νββ decay up to a half life of 2 .1026 yr in two phases: Phase I of the experiment has been concluded last year. No signal is observed and the so far best limit is derived for the half life of the 0 νββ decay of 76Ge, T1/20ν <= 2 . 1 .1025 yr (90% C.L.), after an exposure of 21 . 6 kg .yr. The result refutes an earlier claim of discovery with high probability. The background index of 1 .10-2 cts/(keV .kg .yr) is lower by about one order of magnitude compared to previous experiments. At present the experiment is being upgraded to Phase II. The aim is to collect an exposure of 100kg .yr and further reduce the background by another order of magnitude to a level of <=10-3 cts/(keV .kg .yr). The detector mass will be increased by ~20 kg of new Broad Energy Germanium (BEGe) detectors from enriched 76Ge, which exhibit superior pulse shape discrimination and hence background rejection power. Low mass detector holders, cold front-end electronics, contacting and cabling schemes are redesigned for ultra low mass and radiopurity. In addition, a retractable liquid argon veto will be installed to efficiently suppress background events that induce scintillation in the liquid argon. A hybrid solution of photomultiplier tubes and silicon photomultipliers coupled to scintillating fibres was chosen. This talk gives an account of the results and these challenging modifications to meet our design goals. The Germanium Detector Array (GERDA

  6. Discovering the Majorana neutrino: The next generation of experiments

    SciTech Connect

    Winslow, L. A.

    2015-07-15

    The discovery of a Majorana neutrino would be revolutionary with far-reaching consequences in both particle physics and cosmology. The only feasible experiments to determine the Majorana nature of the neutrino are searches for neutrinoless double-beta decay. The next generation of double-beta decay experiments are being prepared. The general goal is to search for neutrinoless double-beta decay throughout the parameter space corresponding to the inverted hierarchy for neutrino mass. There are a several strong proposals for how to achieve this goal. The status of these efforts is reviewed.

  7. Status of the COBRA double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Janutta, B.; Cobra Collaboration

    2011-08-01

    COBRA is an R&D project, using CdZnTe (CZT) semiconductor detectors to search for the 0νββ decay. CZT is a room temperature semiconductor detector with good energy resolution. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS). In addition to pure energy measurements, pixelated detectors allow for tracking, further reducing the background significantly. The current status of the experiment is presented, including the latest analysis results.

  8. Double Beta Decay of Tellurium-130: Current Status

    NASA Technical Reports Server (NTRS)

    Meshik, A. P.; Hohenberg, C. M.; Pravdivtseva, O. V.; Bernatowicz, T. J.

    2002-01-01

    Geochemically measured values of Te-130 half-life form two distinct clusters. Two different experiments were performed to check two proposed explanations: Xe loss and Xe inheritance. Neither is observed. Additional information is contained in the original extended abstract.

  9. New limits on double beta decay of 106Cd

    NASA Astrophysics Data System (ADS)

    Rukhadze, N. I.; Bakalyarov, A. M.; Briançon, Ch.; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalík, A.; Lebedev, V. I.; Mamedov, F.; Shitov, Yu. A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Zhukov, S. V.

    2011-02-01

    Investigation of double electron capture in 106Cd was performed at the Modane underground laboratory (4800 m.w.e.) using the multi-detector spectrometer TGV-2. In Phase I of the experiment, ˜10 g of 106Cd with an enrichment of 75% was measured during 8687 hours. In Phase II, the TGV-2 background was significantly suppressed in comparison with Phase I and the 106Cd mass was increased to ˜13.6 g. New half-life limits (at 90% CL) were obtained for 2νEC/EC decay of 106Cd to the ground state of Pd106 - T1/2>3.0×10 y (Phase I) and T1/2>3.6×10 y (Phase II, 9000 hours), and for 0νEC/EC decay of 106Cd to the 2741 keV excited state of Pd106 - T1/2>1.1×10 y (Phase II).

  10. On Double-Beta Decay Half-Life Time Systematics

    SciTech Connect

    Pritychenko, B.

    2010-04-14

    Recommended 2{beta}(2{nu}) half-life values and their systematics were analyzed in the framework of a simple empirical approach. T{sub 1/2}{sup 2{nu}} {approx} 1/E{sup 8} trend has been observed for {sup 128,130}Te recommended values. This trend was used to predict T{sub 1/2}{sup 2{nu}} for all isotopes of interest. Current results were compared with other theoretical and experimental works.

  11. Recent developments in the theory of double beta decay

    SciTech Connect

    Iachello, F.; Kotila, J.; Barea, J.

    2013-12-30

    We report results of a novel calculation of phase space factors for 2νβ{sup +}β{sup +}, 2νβ{sup +}EC, 2νECEC, 0νβ{sup +}β{sup +}, and 0νβ{sup +}EC using exact Dirac wave functions, and finite nuclear size and electron screening corrections. We present results of expected half-lives for 0νβ{sup +}β{sup +} and 0νβ{sup +}EC decays obtained by combining the calculation of phase space factors with IBM-2 nuclear matrix elements.

  12. Long-range contributions to double beta decay revisited

    NASA Astrophysics Data System (ADS)

    Helo, J. C.; Hirsch, M.; Ota, T.

    2016-06-01

    We discuss the systematic decomposition of all dimension-7 ( d = 7) lepton number violating operators. These d = 7 operators produce momentum enhanced contributions to the long-range part of the 0νββ decay amplitude and thus are severely constrained by existing half-live limits. In our list of possible models one can find contributions to the long-range amplitude discussed previously in the literature, such as the left-right symmetric model or scalar leptoquarks, as well as some new models not considered before. The d = 7 operators generate Majorana neutrino mass terms either at tree-level, 1-loop or 2-loop level. We systematically compare constraints derived from the mass mechanism to those derived from the long-range 0 νββ decay amplitude and classify our list of models accordingly. We also study one particular example decomposition, which produces neutrino masses at 2-loop level, can fit oscillation data and yields a large contribution to the long-range 0 νββ decay amplitude, in some detail.

  13. The Path to Large-Mass Double Beta Decay Experiments

    SciTech Connect

    Elliott, Steven R.

    2012-08-08

    The technology is ready for atmospheric scale sensitivity and we can at least discuss it for the solar scale. Even null results will be interesting. Supporting measurements are important and have an impact. Need several mesurements with a total uncertainty (experiment and theory) of {approx} 50% or less, and eventually even better. If we see {beta}{beta} the qualitative physics results are profound, but next we'll want to quantify the underlying physics.

  14. CUORE and Beyond: Bolometric Techniques to Explore Inverted Neutrino Mass Hierarchy

    NASA Astrophysics Data System (ADS)

    Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; De Biasi, A.; Deninno, M. M.; Di Domizio, S.; di Vacri, M. L.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will search for neutrinoless double beta decay of 130Te. With 741 kg of TeO2 crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, CUORE will be one of the most competitive neutrinoless double beta decay experiments on the horizon. With five years of live time, CUORE projected neutrinoless double beta decay half-life sensitivity is 1.6 × 1026 y at 1σ (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). Further background rejection with auxiliary light detector can significantly improve the search sensitivity and competitiveness of bolometric detectors to fully explore the inverted neutrino mass hierarchy with 130Te and possibly other double beta decay candidate nuclei.

  15. Germanium-76 Sample Analysis

    SciTech Connect

    Kouzes, Richard T.; Engelhard, Mark H.; Zhu, Zihua

    2011-04-01

    The MAJORANA DEMONSTRATOR is a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). The DEMONSTRATOR will utilize 76Ge from Russia, and the first one gram sample was received from the supplier for analysis on April 24, 2011. The Environmental Molecular Sciences facility, a DOE user facility at PNNL, was used to make the required isotopic and chemical purity measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR. The results of this first analysis are reported here.

  16. Results of the search for neutrinoless double-β decay in 100 with the NEMO-3 experiment

    NASA Astrophysics Data System (ADS)

    Arnold, R.; Augier, C.; Baker, J. D.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Blot, S.; Bongrand, M.; Brudanin, V.; Busto, J.; Caffrey, A. J.; Calvez, S.; Cerna, C.; Cesar, J. P.; Chapon, A.; Chauveau, E.; Duchesneau, D.; Durand, D.; Egorov, V.; Eurin, G.; Evans, J. J.; Fajt, L.; Filosofov, D.; Flack, R.; Garrido, X.; Gómez, H.; Guillon, B.; Guzowski, P.; Hodák, R.; Huber, A.; Hubert, P.; Hugon, C.; Jullian, S.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lalanne, D.; Lang, K.; Lemière, Y.; Le Noblet, T.; Liptak, Z.; Loaiza, P.; Lutter, G.; Mamedov, F.; Marquet, C.; Mauger, F.; Morgan, B.; Mott, J.; Nemchenok, I.; Nomachi, M.; Nova, F.; Nowacki, F.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Povinec, P.; Přidal, P.; Ramachers, Y. A.; Remoto, A.; Reyss, J. L.; Richards, B.; Riddle, C. L.; Rukhadze, E.; Saakyan, R.; Sarazin, X.; Shitov, Yu.; Simard, L.; Šimkovic, F.; Smetana, A.; Smolek, K.; Smolnikov, A.; Söldner-Rembold, S.; Soulé, B.; Štekl, I.; Suhonen, J.; Sutton, C. S.; Szklarz, G.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, Vl. I.; Tretyak, V. I.; Umatov, V. I.; Vanushin, I.; Vilela, C.; Vorobel, V.; Waters, D.; Žukauskas, A.; NEMO-3 Collaboration

    2015-10-01

    The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double-β (0 ν β β ) decay. We report the final results of a search for 0 ν β β decays with 6.914 kg of 100Mo using the entire NEMO-3 data set with a detector live time of 4.96 yr, which corresponds to an exposure of 34.3 kg .yr . We perform a detailed study of the expected background in the 0 ν β β signal region and find no evidence of 0 ν β β decays in the data. The level of observed background in the 0 ν β β signal region [2.8-3.2] MeV is 0.44 ±0.13 counts /yr /kg , and no events are observed in the interval [3.2-10] MeV. We therefore derive a lower limit on the half-life of 0 ν β β decays in 100Mo of T1 /2(0 ν β β )>1.1 ×1 024 yr at the 90% confidence level, under the hypothesis of decay kinematics similar to that for light Majorana neutrino exchange. Depending on the model used for calculating nuclear matrix elements, the limit for the effective Majorana neutrino mass lies in the range ⟨mν⟩<0.33 - 0.62 eV . We also report constraints on other lepton-number violating mechanisms for 0 ν β β decays.

  17. Nuclear transition matrix elements for Majoron-accompanied neutrinoless double-β decay within a projected-Hartree-Fock-Bogoliubov model

    NASA Astrophysics Data System (ADS)

    Rath, P. K.; Chandra, R.; Chaturvedi, K.; Lohani, P.; Raina, P. K.

    2016-02-01

    The model-dependent uncertainties in the nuclear transition matrix elements for the Majoron-accompanied neutrinoless double-β decay (0+→0+transition) of Zr,9694, 100Mo, Te,130128, and 150Nd isotopes are calculated by employing the projected-Hartree-Fock-Bogoliubov formalism with four different parametrizations of the pairing plus multipolar two-body interactions and three different parametrizations of the Jastrow short-range correlations. Uncertainties in the nuclear transition matrix elements turn out to be less than 15% and 21% for decays involving the emission of single and double Majorons, respectively.

  18. Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-β decay

    NASA Astrophysics Data System (ADS)

    Yao, J. M.; Engel, J.

    2016-07-01

    We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes 150Nd and 150Sm and of the nuclear matrix element that governs the neutrinoless double-β decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-β decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-β decay matrix element, so that the overall octupole-induced quenching is only about 7 % .

  19. A Direct Dark Matter Search with the MAJORANA Low-Background Broad Energy Germanium Detector

    NASA Astrophysics Data System (ADS)

    Finnerty, Padraic Seamus

    It is well established that a significant portion of our Universe is comprised of invisible, non-luminous matter, commonly referred to as dark matter. The detection and characterization of this missing matter is an active area of research in cosmology and particle astrophysics. A general class of candidates for non-baryonic particle dark matter is weakly interacting massive particles (WIMPs). WIMPs emerge naturally from supersymmetry with predicted masses between 1--1000 GeV. There are many current and near-future experiments that may shed light on the nature of dark matter by directly detecting WIMP-nucleus scattering events. The MAJORANA experiment will use p-type point contact (PPC) germanium detectors as both the source and detector to search for neutrinoless double-beta decay in 76Ge. These detectors have both exceptional energy resolution and low-energy thresholds. The low-energy performance of PPC detectors, due to their low-capacitance point-contact design, makes them suitable for direct dark matter searches. As a part of the research and development efforts for the MAJORANA experiment, a custom Canberra PPC detector has been deployed at the Kimballton Underground Research Facility in Ripplemead, Virginia. This detector has been used to perform a search for low-mass (< 10 GeV) WIMP induced nuclear recoils using a 221.49 live-day exposure. It was found that events originating near the surface of the detector plague the signal region, even after all cuts. For this reason, only an upper limit on WIMP induced nuclear recoils was placed. This limit is inconsistent with several recent claims to have observed light WIMP based dark matter.

  20. Results from KamLAND-Zen

    NASA Astrophysics Data System (ADS)

    Inoue, K.

    2013-02-01

    KamLAND-Zen has started a search for neutrino-less double beta decay with 320kg of 90% enriched 136Xe in September 2011. Results from initial 112 day of measurement are presented. It provides so far the most precise two-neutrino-mode half-life of 136Xe and the most stringent upper limit of the coupling constant of the ordinary Majoron-emitting double-beta-decay. The search for neutrino-less mode has achieved top class sensitivity but is struggling with unexpected backgrounds. Origin of the background and prospects for the future improvements are also discussed.