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Sample records for jyfltrap-assisted beta-decay studies

  1. Neutron beta decay studies with Nab

    NASA Astrophysics Data System (ADS)

    Baeßler, S.; Alarcon, R.; Alonzi, L. P.; Balascuta, S.; Barrón-Palos, L.; Bowman, J. D.; Bychkov, M. A.; Byrne, J.; Calarco, J. R.; Chupp, T.; Cianciolo, T. V.; Crawford, C.; Frlež, E.; Gericke, M. T.; Glück, F.; Greene, G. L.; Grzywacz, R. K.; Gudkov, V.; Harrison, D.; Hersman, F. W.; Ito, T.; Makela, M.; Martin, J.; McGaughey, P. L.; McGovern, S.; Page, S.; Penttilä, S. I.; Počanić, D.; Rykaczewski, K. P.; Salas-Bacci, A.; Tompkins, Z.; Wagner, D.; Wilburn, W. S.; Young, A. R.

    2013-10-01

    Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer.

  2. {beta}-decay study of {sup 77}Cu

    SciTech Connect

    Patronis, N.; De Witte, H.; Gorska, M.; Huyse, M.; Kruglov, K.; Pauwels, D.; Van de Vel, K.; Van Duppen, P.; Van Roosbroeck, J.; Thomas, J.-C.; Materna, T.; Mathieu, L.; Serot, O.

    2009-09-15

    A {beta}-decay study of {sup 77}Cu has been performed at the ISOLDE mass separator with the aim to deduce its {beta}-decay properties and to obtain spectroscopic information on {sup 77}Zn. Neutron-rich copper isotopes were produced by means of proton- or neutron-induced fission reactions on {sup 238}U. After the production, {sup 77}Cu was selectively laser ionized, mass separated, and sent to different detection systems where {beta}-{gamma} and {beta}-n coincidence data were collected. We report on the deduced half-live, decay scheme, and possible spin assignment of {sup 77}Cu.

  3. Spectroscopic Studies of Double Beta Decays and MOON

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    2007-10-01

    This is a brief review of future spectroscopic experiments of neutrino-less double beta decays (0νββ) and the MOON (Mo Observatory Of Neutrinos) project. Spectroscopic 0νββ experiments of MOON, SuperNEMO and DCBA are planned to study Majorana masses in the quasi-degenerate (QD) and inverted mass hierarchy (IH) regions. MOON aims at 0νββ studies with the ν-mass sensitivities of 100-30 meV by means of a super ensemble of multi-layer modules, each being consist of a scintillator plate, two tracking detector planes and a thin ββ source film.

  4. Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure

    SciTech Connect

    Algora, A.; Valencia, E.; Tain, J. L.; Jordan, M. D.; Agramunt, J.; Rubio, B.; Estevez, E.; Molina, F.; Montaner, A.; Guadilla, V.; Fallot, M.; Podolyak, Zs.; Regan, P. H.; Gelletly, W.; Bowry, M.; Mason, P.; Farrelly, G. F.; Rissanen, J.; Eronen, T.; Moore, I.; Penttila, H.; Aysto, J.; Eloma, V.; Hakala, J.; Jokinen, A.; Kolkinen, V.; Reponen, M.; Sonnenschein, V.; Cano-Ott, D.; Martinez, T.; Mendoza, E.; Garcia, A. R.; Gomez-Hornillos, M. B.; Gorlychev, V.; Caballero-Folch, R.; Kondev, F. G.; Sonzogni, A. A.

    2014-06-01

    We present an overview of our activities related to the study of the beta decay of neutron rich nuclei relevant for nuclear applications. Recent results of the study of the beta decay of Br using a new segmented total absorption spectrometer are presented. Our measurements were performed at the IGISOL facility using trap-assisted total absorption spectroscopy.

  5. Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure

    SciTech Connect

    Algora, A.; Valencia, E.; Taín, J.L.; Jordan, M.D.; Agramunt, J.; Rubio, B.; Estevez, E.; Molina, F.; Montaner, A.; Guadilla, V.; Fallot, M.; Porta, A.; Zakari-Issoufou, A.-A.; Bui, V.M.; and others

    2014-06-15

    An overview is given of our activities related to the study of the beta decay of neutron rich nuclei relevant for nuclear applications. Recent results of the study of the beta decay of {sup 87,88}Br using a new segmented total absorption spectrometer are presented. The measurements were performed at the IGISOL facility using trap-assisted total absorption spectroscopy.

  6. CANDLES for the study of ^48Ca double beta decay

    NASA Astrophysics Data System (ADS)

    Ogawa, Izumi

    2009-10-01

    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 gave the best lower limit on the half-life of neutrino-less double beta decay of ^48Ca by using CaF2(Eu) detector system, ELEGANT VI though further development is highly desirable to reach the mass region of current interest. 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. We are now moving the detector system to new experimental room (room D) at Kamioka underground laboratory (2700 m.w.e.) to avoid large background originated from cosmic rays. At the same time, we are increasing the total mass of the ^48Ca compared to the one in the prototype detector. 96 (instead of 60 in prototype) CaF2 modules which contains 350 g of ^48Ca are immersed in a liquid scintillator (LS) which acts as an active veto (veto phase). The conversion phase contains wavelength shifter (Bis-MSB) which converts the emission light of CaF2(pure) which has a peak in the UV region to the visible one where the quantum efficiency of the PMTs is high enough (maximum at ˜400 nm) and materials at the optical path have good transparencies. Scintillation lights from both the CaF2 modules and the liquid scintillator in veto phase are viewed by large PMTs (48 x13'' and 14 x17'' tubes). All the detector system described above are contained in a water tank which is 3 m in diameter and 4 m in height. The water tank and a purification system of the LS together with LS storage tanks were installed at room D. The purification system of the LS removes the

  7. MOON for neutrino-less double beta decays. Majorana neutrinos by spectroscopic studies of double beta decays

    NASA Astrophysics Data System (ADS)

    Ejiri, H.; Doe, P.; Elliott, S. R.; Engel, J.; Finger, M., Jr.; Finger, M.; Fushimi, K.; Gehman, V.; Greenfield, M.; Hazama, R.; Kavitov, P.; Kekelidze, V.; Nakamura, H.; Nomachi, M.; Robertson, R. G. H.; Shima, T.; Slunecka, M.; Shirkov, G.; Sissakian, A.; Titov, A.; Umehara, S.; Vaturin, V.; Voronov, V.; Wilkerson, J. F.; Will, D. I.; Yoshida, S.; Vrba, V.

    2008-08-01

    The MOON (Majorana/Mo Observatory Of Neutrinos) project aims at studies of the Majorana nature of the neutrino ( ν) and the ν-mass spectrum by spectroscopic experiments of neutrino-less double beta decays (0 νββ) with the ν-mass sensitivity of < m {/ν m }> = 100-30 meV. The solid scintillator option of the MOON detector is a super ensemble of multi-layer modules, each being composed by PL scintillator plates and position-sensitive detector planes with good overall energy resolution of σ ≈ 2% at the Q ββ ≈ 3 MeV. Thin ββ source films are interleaved between the detector planes. High localization of the two β tracks enables one to select true signals and reject BG ones. The multi-layer structure of the detector makes it realistic to build a compact ton-scale detector. MOON with detector ≠ ββ source is used for studying 0 νββ decays from 100Mo, 82Se and other ββ isotopes with large Q ββ . Real-time exclusive measurements of low energy solar neutrinos can be made by observing inverse β rays from solar- ν captures of 100Mo in delayed coincidence with the subsequent β decay of 100Tc.

  8. Double Beta Decay of ^48Ca Studied by ELEGANTS VI

    NASA Astrophysics Data System (ADS)

    Ogawa, Izumi; Kishimoto, Kohji; Umehara, Saori; Katuski, Atsunari; Sakai, Hitoshi; Yokoyama, Daisuke; Mukaida, Kentaro; Tomii, Satoshi; Ajimura, Shuhei; Matsuoka, Kenji; Kishimoto, Tadafumi

    2001-10-01

    A CaF2 scintillation detector system (ELEGANT VI) is developed to search for neutrino-less double beta decay (0νββ) of ^48Ca and spin coupled dark matter. ^48Ca is the most factorable isotope among other potential ββ decay nuclei because it has the largest Q-value (4.27 MeV) of the decay ^48Ca arrow ^48Tl then the possibility of the occurrence is highest and little background is expected. CsI(Tl) scintillators and active lightguides (pure CaF2 crystals) which are on both sides of the central CaF_2(Eu) crystal act as 4π active shields. The whole system is in operation at the underground laboratory located in Nara (Oto Cosmo Observatory) which has effectively 1.4 km water equivalent shield. We will report our current status of the investigation.

  9. Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model

    SciTech Connect

    Zuffi, L.; Brant, S.; Yoshida, N.

    2006-04-26

    We study {beta}-decay in odd-A nuclei together with the energy levels and other properties in the proton-neutron interacting-boson-fermion model. We also report on the preliminary results in the odd-odd nuclei in the proton-neutron interacting boson-fermion-fermion model.

  10. The CANDLES experiment for the study of Ca-48 double beta decay

    NASA Astrophysics Data System (ADS)

    Iida, T.; Kishimoto, T.; Nomachi, M.; Ajimura, S.; Umehara, S.; Nakajima, K.; Ichimura, K.; Yoshida, S.; Suzuki, K.; Kakubata, H.; Wang, W.; Chan, W. M.; Trang, V. T. T.; Doihara, M.; Ishikawa, T.; Tanaka, D.; Tanaka, M.; Maeda, T.; Ohata, T.; Tetsuno, K.; Tamagawa, Y.; Ogawa, I.; Tomita, S.; Fujita, G.; Kawamura, A.; Harada, T.; Inukai, Y.; Sakamoto, K.; Yoshizawa, M.; Fushimi, K.; Hazama, R.; Nakatani, N.; Osumi, H.; Okada, K.

    2016-04-01

    CANDLES studies the double beta decay of 48Ca through CaF2 scintillation crystals. The CANDLES III detector, located in Kamioka underground laboratory, is currently running. Here we describe recent status of data analysis which includes detector performance, detector stability, and background estimation. Current sensitivity for 0 νββ half-life is also discussed in this paper.

  11. 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.

  12. Matter dominated universe and study of {sup 48}Ca double beta decay

    SciTech Connect

    Kishimoto, Tadafumi

    2010-08-12

    We have been studying double beta decay of {sup 48}Ca. Neutrino-less double beta decay (0{nu}{beta}{beta}) is currently known to be only experiment to verify whether lepton number is not conserved. The non-conservation is the key to create matter dominated universe by the so-called Leptogenesys. 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 developing CANDLES detector system to sense much longer life-time region. We have developed techniques to reduce backgrounds further. The CADLES detector system was installed at Kamioka underground laboratory. Here I describe a schematic view of the system.

  13. Investigation of excited states in 47Ca through a high-statistics beta-decay study

    NASA Astrophysics Data System (ADS)

    Smith, Jenna; Griffin Collaboration

    2015-10-01

    Recent developments in nuclear many-body calculation methods have extended the application of ab initio interactions to the calcium isotopes (e.g. Refs.). Detailed nuclear data for these isotopes are necessary to evaluate the many-body calculation methods and to test the predictive power of the interactions. Transfer reactions from 48Ca have identified many excited states of 47Ca, but only four states have been identified in previous beta-decay experiments. High-statistics beta-decay studies using modern detection systems can provide detailed information on level energies, branching ratios, and spin/parity assignments, while comparison to other population methods can yield information about the structure of these states. A recent experiment at TRIUMF-ISAC used the GRIFFIN spectrometer to investigate the levels populated by beta decay in more detail. The decay scheme has been considerably extended and angular correlations between cascading gamma-ray transitions allow spin and parity assignments to be made for some of the observed excited states. An overview of the experimental apparatus as well as a discussion of the results from preliminary analysis will be presented.

  14. Beta-decay studies of states in 12C

    NASA Astrophysics Data System (ADS)

    Pedersen, Solveig; Alcorta, M.; Borge, M. J. G.; Brandenburg, S.; Büscher, J.; Dendooven, P.; Diget, C. Aa.; Van Duppen, P.; Fulton, B.; Fynbo, H. O. U.; Huyse, M.; Jokinen, A.; Jonson, B.; Jungmann, K.; Madurga, M.; Nyman, G.; Onderwater, C. J. G.; Perajärvi, K.; Raabe, R.; Riisager, K.; Rogachevskiy, A.; Saastamoinen, A.; Sohani, M.; Tengblad, O.; Traykov, E.; Wilschut, H. W.; Äystö, J.

    The interest in experimental studies of the 12 C nucleus is partly due to the astrophysical interest in its spectroscopic properties, which determine the triple alpha reaction rate, and partly motivated by the structure of this nucleus, which is not fully explained theoretically. Some aspects are described in the shell model and others by a cluster structure of three alpha particles, but both cannot so far be combined in a unified model. New experiments have been performed to address these problems. The focus of this work is on an implantation experiment, which took place in April 2006 at KVI.

  15. Detailed {beta}-decay study of {sup 33}Ar

    SciTech Connect

    Adimi, N.; Dominguez-Reyes, R.; Alcorta, M.; Borge, M. J. G.; Madurga, M.; Perea, A.; Tengblad, O.; Bey, A.; Blank, B.; Dossat, C.; Giovinazzo, J.; Matea, I.; Fynbo, H. O. U.; Knudsen, H. H.; Suemmerer, K.

    2010-02-15

    The proton-rich nucleus {sup 33}Ar has been studied by detailed proton and {gamma}-ray spectroscopy at the low-energy facility of SPIRAL at GANIL. Proton and {gamma}-ray singles and coincidence measurements allowed to establish a quasicomplete decay scheme of this nucleus. By comparing the proton intensity to different daughter states, tentative spin assignments have been made for some of the states of {sup 33}Cl. The Gamow-Teller strength distribution is deduced and compared to shell-model calculations and a quenching factor is determined. States close to the isobaric analog state are searched for with respect to isospin mixing.

  16. Beta Decay Studies of Short Lived Barium Isotopes

    NASA Astrophysics Data System (ADS)

    Bendall, Charles Skipwith

    The half-lives and relative intensities of several short lived neutron rich isotopes, with atomic numbers between 54 and 57, produced in the spontaneous fission of californium-252 were determined. This was accomplished from the study of the time variation of the K X-ray yields of these isotopes. A transport system which allowed us to study isotopes with half-lives less than 10 seconds was developed. Mass assignments were made by comparing the experimental values of the half-lives with known values. A beta K X-ray coincidence technique was used to obtain the barium beta spectrum in coincidence with lanthanum K X -rays. A Kurie plot was performed on the spectrum to determine the beta groups. The probable origin of each beta group was determined through a comparison of the relative intensities of the isotopes and beta groups. Four beta groups probably from the decay of Ba-145 were revealed. The end point energies of these beta groups are 3870 (+OR-) 432 keV, 2772 (+OR-) 112 keV, 1894 (+OR-) 58 keV, and 746 (+OR-) 38 keV. The three lowest energy groups have not been observed before.

  17. Beta decay studies around doubly magic 78Ni

    NASA Astrophysics Data System (ADS)

    Rykaczewski, Krzysztof

    2007-11-01

    The main motivations to study very neutron rich nuclei in the ^ 78Ni region are related to the evolution of nuclear structure and to the path of nucleosynthesis within rapid neutron capture. In particular, neutrons filling g9/2 orbital between ^68Ni and ^78Ni affect spin-orbit splitting of proton single-particle states. An increasing beta- delayed neutron emission probabilities are changing the isobaric distributions of nuclei involved in the r-process. The report on the recent results on the decay of most neutron- rich isotopes of copper and gallium [1] will be presented. These proton-induced ^238U fission products were produced and studied at Holifield Radioactive Ion Beam Facility at Oak Ridge using a ``ranging-out'' method [2] for postaccelerated beams purification. In collaboration with Jeff Winger and Sergey Iliushkin, Mississippi State University; Carl Gross and Dan Shapira, ORNL; Carrol Bingham, UTK; Robert Grzywacz, ORNL; Chiara Mazzocchi, Sean Liddick, Steven Padgett, and Mustafa Rajabali, UTK; Jon Batchelder, UNIRIB-ORAU; Edward Zganjar and Andreas Piechaczek, LSU; Christopher Goodin and Joseph Hamilton, Vanderbilt University; and Wojciech Krolas, JIHIR Oak Ridge.[1] J. Winger et al., contr. to INPC, Japan, June 2007[2] C.J. Gross et al., EPJ A 25, s01, 115 (2005)

  18. Beta Decay Study of Neutron-rich Magnesium

    NASA Astrophysics Data System (ADS)

    Ash, John; Rajabali, Mustafa; Griffin Collaboration

    2015-10-01

    Within the ``island of inversion'' around the N = 20 shell gap, isotopes of magnesium, and aluminum deviate from the expected closed-shell structure. Particles promoted across the N = 20 shell gap result in a lower energy deformed ground state configuration rather than the expected spherical configuration. An experiment was conducted at TRIUMF laboratory in the summer of 2015 to study the decay of ``island of inversion'' isotopes 33 , 34 , 35Mg and the structure of the respective daughter nuclei. The isotopes of interest were produced by a proton beam from TRIUMF's 500 MeV cyclotron impacting on a UCx target. The magnesium decays populated states along the decay chain in Al, Si, P, and S isotopes. The new GRIFFIN spectrometer in the ISAC-I facility was used to detect the gamma rays. Two sets of scintillators, one for detecting the beta particles (SCEPTAR) and the other for detecting beta-delayed neutrons (DESCANT), were also used in conjunction with GRIFFIN. The GRIFFIN data were energy calibrated and partially analyzed for this project. New algorithms were developed for the analysis. Preliminary results for new transitions detected in 34Mg as well as the half lives obtained will be presented in their current form. This research was supported by the Tennessee Tech research office.

  19. Radiative Beta Decay for Studies of CP Violation

    NASA Astrophysics Data System (ADS)

    Gardner, Susan; He, Daheng

    2013-10-01

    A triple-product correlation in the radiative β decay rate of neutrons or of nuclei, characterized by the kinematical variable, where, e.g., n (p) --> p (p') +e- (le) + νe (lν) + γ (k) , can be generated by the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and SU(2)L ×U(1)Y gauge invariance at low energies. The correlation probes the imaginary part of its coupling constant, so that its observation at anticipated levels of sensitivity would reflect the presence of sources of CP violation beyond the standard model. We compute the size of the asymmetry in n --> pe-νe γ decay in chiral effective theory, compare it with the computed background from standard-model final-state interactions, and consider the new physics scenarios which would be limited by its experimental study. Work supported in part by the U.S. Department of Energy Office of Nuclear Physics under contract no. DE-FG02-96ER40989.

  20. MOON for symmetry studies of neutrinos by double beta decays and neutrino nuclear responses

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    2010-11-01

    Neutrino-less double beta decays (0νββ) are used for high sensitivity studies of symmetry properties of neutrinos such as the Majorana nature of neutrinos, the absolute mass scale, the CP at the lepton sector, and others. Neutrino nuclear responses (0νββ nuclear matrix elements) are crucial for extracting these neutrino properties from 0νββ experiments. This is a brief report of the present status of MOON (spectroscopic 0νββ experiment) with the ν-mass sensitivity of 100-30 meV, and experimental ways to study the neutrino nuclear responses.

  1. 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.

  2. Beta-decay study of neutron rich isotopes of Bromine and Krypton

    SciTech Connect

    Miernik, Krzysztof A; Gross, Carl J; Grzywacz, Robert Kazimierz; Madurga, M; Mendez, II, Anthony J; Miller, D.; Padgett, S; Paulauskas, Stanley V; Rykaczewski, Krzysztof Piotr; Stracener, Daniel W; Wolinska-Cichocka, Marzena; Zganjar, E. F.; Batchelder, J. C.; Brewer, N.T.; Cartegni, L.; Fijalkowska, Aleksandra G; Hamilton, J. H.; Hwang, J. K.; Ilyushkin, S.; Jost, Carola U; Karny, M.; Korgul, A.; Krolas, W.; Liu, S.H.; Ramayya, A. V.; Surman, Rebecca; Winger, J. A.; Wolinska-Cichocka, M

    2013-01-01

    Short lived neutron rich nuclei including 93 Br, 93 Kr and 94 Kr were produced in proton induced fission of 238 U at the HRIBF in Oak Ridge. Their beta decay was studied by means of a high resolution on line mass separator and beta gamma spectroscopy methods. The half life of 93Br T1/2 = 152(8) ms and delayed branching ratio of Pn = 53-8+11 may be compared to the previously reported values of T1/2 = 102(10) ms and Pn = 68(7)%. At the same time the half life of 94Kr T1/2 = 227(14) ms and B delayed branching ratio of Pn = 1.9+0.6 0.2 % of 93Kr are in very good agreement with literature values. The decay properties of 93Br include four new gamma transitions following beta delayed neutron emission.

  3. 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.

  4. Majorana Neutrino Masses by Spectroscopic Studies of Double Beta Decays and Moon

    NASA Astrophysics Data System (ADS)

    Ejiri, Hiroyasu

    This is a brief review of spectroscopic studies of neutrino-less double beta decays (0νββ) and the MOON (Mo Observatory Of Neutrinos) project. It aims at studying the Majorana nature of neutrinos and the mass spectrum by spectroscopic studies of 0νββ with ν-mass sensitivity of ≈ 30 meV. The solid scintillator option of the MOON detector is a super ensemble of multi-layer modules, each being composed by a scintillator plate and two tracking detector planes. Thin ββ source films are interleaved between the detector planes. High localization of the two β tracks enables one to select true signals and reject BG ones by spatial and time correlation analyses. MOON with detector ≠ ββ source is used for studying 0νββ decays from 100Mo, 82Se and other ββ isotopes with large nuclear sensitivity (large Qββ). Real-time exclusive measurements of low energy solar neutrinos can also be made by observing inverse β rays from solar-ν captures of 100Mo in delayed coincidence with the subsequent β decay of 100Tc.

  5. Beta-Decay Study of ^{150}Er, ^{152}Yb, and ^{156}Yb: Candidates for a Monoenergetic Neutrino Beam Facility

    SciTech Connect

    Estevez Aguado, M. E.; Algora, A.; Rubio, B.; Bernabeu, J.; Nacher, E.; Tain, J. L.; Gadea, A.; Agramunt, J.; Burkard, K.; Hueller, W.; Doring, J.; Kirchner, R.; Mukha, I.; Plettner, C.; Roeckl, E.; Grawe, H.; Collatz, R.; Hellstrom, M.; Cano-Ott, D.; Karny, M.; Janas, Z.; Gierlik, M.; Plochocki, A.; Rykaczewski, Krzysztof Piotr; Batist, L.; Moroz, F.; Wittman, V.; Blazhev, A.; Valiente, J. J.; Espinoza, C.

    2011-01-01

    The beta decays of ^{150}Er, ^{152}Yb, and ^{156}Yb nuclei are investigated using the total absorption spectroscopy technique. These nuclei can be considered possible candidates for forming the beam of a monoenergetic neutrino beam facility based on the electron capture (EC) decay of radioactive nuclei. Our measurements confirm that for the cases studied, the EC decay proceeds mainly to a single state in the daughter nucleus.

  6. 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.

  7. 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.

  8. Double beta decay: Calorimeters

    NASA Astrophysics Data System (ADS)

    Brofferio, Chiara

    2008-11-01

    Calorimeters or, with a more specific definition, low temperature detectors, have been used by now for more than 15 years in Double Beta Decay (DBD) searches, with excellent results: they compete with Ge diodes for the rank of detectors with the highest sensitivity to the effective neutrino mass, which is defined as a linear combination of the neutrino mass eigenvalues. After a brief introduction to the argument, with some notes on DBD and on bolometers, an update on the now closed experiment CUORICINO and on its successor, CUORE, is given. The fundamental role of background is then revealed and commented, introducing in this way the importance of the specific experiment now under construction, CUORE-0, that will precede CUORE to help optimizing the struggle against surface background. The possible future of this technique is then commented, quoting important R&D studies that are going on, for active shielding bolometers and for scintillating bolometers coupled with light detecting bolometers.

  9. beta. -decay asymmetry of the free neutron

    SciTech Connect

    Bopp, P.; Dubbers, D.; Klemt, E.; Last, J.; Schuetze, H.; Weibler, W.; Freedman, S.J.; Schaerpf, O.

    1983-01-01

    The ..beta..-decay of polarized neutrons has been studied with the new superconducting spectrometer PERKEO at the ILL. The energy dependence of the ..beta..-decay asymmetry has been measured for the first time. From the measured ..beta..-asymmetry parameter we obtain a new value for the ratio of weak coupling constants g/sub A//g/sub V/. 11 references.

  10. Experimental study of {sup 113}Cd {beta} decay using CdZnTe detectors

    SciTech Connect

    Goessling, C.; Kiel, H.; Muenstermann, D.; Oehl, S.; Junker, M.; Zuber, K.

    2005-12-15

    A search for the fourfold forbidden {beta} decay of {sup 113}Cd has been performed with CdZnTe semiconductors. With 0.86 kg {center_dot} d of statistics a half-life for the decay of T{sub 1/2}=[8.2{+-}0.2(stat.){sub -1.0}{sup +0.2}(sys.)]x10{sup 15} yr has been obtained. This is in good agreement with published values. A comparison of the spectral shape with the one given on the Table of Isotopes Web page shows a severe deviation.

  11. Beta Decay Studies of Proton Rich Nuclei, an Important Ingredient for rp-Process Calculations

    NASA Astrophysics Data System (ADS)

    Rubio, B.; Kucuk, L.; Orrigo, S. E. A.; Fujita, Y.; Gelletly, W.; Blank, B.; Adachi, T.; Aguilera, P.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; de France, G.; de Oliveira Santos, F.; Fujita, H.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kurtukian-Nieto, T.; Marqués, M.; Molina, F.; Nishimura, D.; Oikawa, H.; Oktem, Y.; Perrot, L.; Popescu, L.; Raabe, R.; Rogers, A. M.; Srivastava, P. C.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

    We have performed a series of beta-decay experiments at fragmentation facilities on Tz = -1/2, Tz = -1, and Tz = -2 nuclei. Most of these nuclei lie on the rp-process path and therefore some of the quantities we have measured such as T1/2 values are important ingredients in performing reaction flow calculations for light curve estimates and testing astrophysical models of X-ray bursters. At this conference we have presented the results of measurements of T1/2 values for 25 nuclei and compared with previous values.

  12. High Resolution Charge Exchange Reaction and Analogous {beta}-decay for the Study of Gamow-Teller Transition Strengths

    SciTech Connect

    Fujita, Y.; Rubio, B.

    2007-06-13

    Isospin symmetry is expected for the Tz = {+-}1 {yields} 0 isobaric analogous transitions in isobars with mass number A, where Tz is the z component of isospin T. Assuming this symmetry, strengths of analogous Gamow-Teller (GT) transitions within A = 50 isobars were determined from a high energy-resolution Tz = + 1 {yields} 0, 50Cr(3He,t)50Mn study at 0 deg. in combination with the decay Q-value and lifetime from the Tz = -1 {yields} 0, 50Fe{yields}50Mn {beta} decay. This method can be applied to other pf-shell nuclei and can be used to study GT strengths of astrophysical interest.

  13. MOON for spectroscopic studies of double beta decays and the present status of the MOON-1 prototype detector

    NASA Astrophysics Data System (ADS)

    Nakamura, H.; Ejiri, H.; Fushimi, K.; Ichihara, K.; Matsuoka, K.; Nomachi, M.; Hazama, R.; Umehara, S.; Yoshida, S.; Ogama, T.; Sakiuchi, T.; Hai, V. H.; Sugaya, Y.; Moon Collaboration

    2006-05-01

    The MOON (Molybdenum Observatory Of Neutrinos) project, as an extension of ELEGANT V, aims at spectroscopic studies of double beta decays from 100Mo with a sensitivity of the Majorana neutrino mass around 30 meV. Measurements with good energy and position resolutions enable one to select true signals and to reject background ones. A prototype MOON detector (MOON Phase-1A) with 142 g 100Mo was built and is running at the Oto underground laboratory. The present report describes briefly the outline of the MOON project and the present status of MOON-1.

  14. Beta decay studies with total absorption spectroscopy and the Lucrecia spectrometer at ISOLDE

    NASA Astrophysics Data System (ADS)

    Rubio, B.; Gelletly, W.; Algora, A.; Nacher, E.; Tain, J. L.

    2017-08-01

    Here we present the experimental activities carried out at ISOLDE with the total absorption spectrometer Lucrecia, a large 4π scintillator detector designed to absorb a full gamma cascade following beta decay. This spectrometer is designed to measure β-feeding to excited states without the systematic error called Pandemonium. The set up allows the measurement of decays of very short half life. Experimental results from several campaigns, that focus on the determination of the shapes of β-decaying nuclei by measuring their β decay strength distributions as a function of excitation energy in the daughter nucleus, are presented. This article belongs to the Focus on Exotic Beams at ISOLDE: A Laboratory Portrait special issue.

  15. 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.

  16. 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.

  17. A setup for Ba-ion extraction from high pressure Xe gas for double-beta decay studies with EXO

    NASA Astrophysics Data System (ADS)

    Brunner, T.; Fudenberg, D.; Sabourov, A.; Varentsov, V. L.; Gratta, G.; Sinclair, D.

    2013-12-01

    An experimental setup is being developed to extract Ba ions from a high-pressure Xe gas environment. It aims to transport Ba ions from 10 bar Xe to vacuum conditions. The setup utilizes a converging-diverging nozzle in combination with a radio-frequency (RF) funnel to move Ba ions into vacuum through the pressure drop of several orders of magnitude. This technique is intended for use in a future multi-ton detector investigating double-beta decay in 136Xe. Efficient extraction and detection of Ba ions, the decay product of 136Xe, would allow for a background-free measurement of the 136Xe double-beta decay.

  18. Simulation studies of muon-produced background events deep underground and consequences for double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Massarczyk, Ralph; Majorana Collaboration

    2015-10-01

    Cosmic radiation creates a significant background for low count rate experiments. The Majorana demonstrator experiment is located at the Sanford Underground Research Facility at a depth of 4850ft below the surface but it can still be penetrated by cosmic muons with initial energies above the TeV range. The interaction of muons with the rock, the shielding material in the lab and the detector itself can produce showers of secondary particles, like fast neutrons, which are able to travel through shielding material and can produce high-energy γ-rays via capture or inelastic scattering. The energy deposition of these γ rays in the detector can overlap with energy region of interest for the neutrino-less double beta decay. Recent studies for cosmic muons penetrating the Majorana demonstrator are made with the Geant4 code. The results of these simulations will be presented in this talk and an overview of the interaction of the shower particles with the detector, shielding and veto system will be given. 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. Supported by U.S. Department of Energy through the LANL/LDRD Program.

  19. Superallowed Fermi beta decay

    SciTech Connect

    Hardy, J. C.; Towner, I. S.

    1998-12-21

    Superallowed 0{sup +}{yields}0{sup +} nuclear beta decay provides a direct measure of the weak vector coupling constant, G{sub V}. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of {sup 10}C to that of {sup 54}Co, and demonstrate that the results confirm conservation of the weak vector current (CVC) but differ at the 98% confidence level from the unitarity condition for the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We examine the reliability of the small calculated corrections that have been applied to the data, and assess the likelihood of even higher quality nuclear data becoming available to confirm or deny the discrepancy. Some of the required experiments depend upon the availability of intense radioactive beams. Others are possible today.

  20. Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Fiorini, Ettore

    2007-06-01

    The recent results showing the presence of neutrino oscillations clearly indicate that the difference between the squared mass of neutrinos of different flavors is different from zero, but are unable to determine the nature and the absolute value of the neutrino mass. Neutrinoless double beta decay (DBD) is at present the most powerful tool to ascertain if the neutrino is a Majorana particle and to determine under this condition the absolute value of its mass. The results already obtained in this lepton violating process will be reported and the two presently running DBD experiments briefly discussed. The future second generation experiments will be reviewed with special emphasis to those already partially approved. In conclusion the peculiar and interdisciplinary nature of these searches will be stressed in their exciting aim to discover if neutrino is Dirac or Majorana particle.

  1. 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.

  2. Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Fiorini, Ettore

    2010-12-01

    Almost exactly seventy years ago and only one year before his tragic disappearance the ingenious idea of Ettore Majorana is becoming one of the most important step in the development of fundamental physics. The problem of the nature of the neutrino, namely if it is a massless Dirac particle different from its antineutrino or a Majorana particle with finite mass, is discussed. In fact the recent results showing the presence of neutrino oscillations clearly indicates that the difference between the squared mass of neutrinos of different flavours is finite. Neutrinoless double beta decay (DBD) is at present the most powerful tool to determine the effective value of the mass of a Majorana neutrino. The results already obtained in this lepton violating process will be reported and the two presently running DBD experiments briefly discussed. The future second generation experiments will be reviewed with special emphasis to those already at least partially approved. In conclusion the peculiar and interdisciplinary nature of these searches will be stressed in their exciting aim to discover if neutrino is indeed a Majorana particle.

  3. 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

  4. Total absorption spectroscopy study of the beta decay of fission products for reactor anti-neutrino energy spectra calculation

    NASA Astrophysics Data System (ADS)

    Fijalkowska, Aleksandra; MTAS Collaboration

    2016-09-01

    Thanks to its high efficiency for the detection of gamma-radiation, total absorption spectroscopy is an ideal technique to establish the true beta-decay feeding. The knowledge of the decay scheme is used to determine the distribution of anti-neutrino energy released in the decay. The anti-neutrino energy spectrum is used to calculate the total anti-neutrino flux emitted by reactor cores and the number of reactor anti-neutrino interactions with the detector matter. The number of measured anti-neutrino interactions with detector matter is about 6% smaller than the expected number of events. The measurements of beta decay of fission products by means of total absorption technique allow to verify expected number of anti-neutrino interactions with matter. In this contribution we would like to present the results of total absorption measurement of the beta decay of 86Br, 89Rb, 89Kr, 90gsRb, 90mRb, 90Kr and 139Xe, nuclei abundantly produced in the reactor core. The results and their impact on the anti-neutrino spectra reconstruction will be presented and discussed. This work was supported by the Office of Nuclear Physics, U. S. Department of Energy under Contracts DE-AC05-00OR22725 and by the Polish National Science Center under Contracts UMO2013/08/T/ST2/00624.

  5. Questions Students Ask: Beta Decay.

    ERIC Educational Resources Information Center

    Koss, Jordan; Hartt, Kenneth

    1988-01-01

    Answers a student's question about the emission of a positron from a nucleus. Discusses the problem from the aspects of the uncertainty principle, beta decay, the Fermi Theory, and modern physics. (YP)

  6. Questions Students Ask: Beta Decay.

    ERIC Educational Resources Information Center

    Koss, Jordan; Hartt, Kenneth

    1988-01-01

    Answers a student's question about the emission of a positron from a nucleus. Discusses the problem from the aspects of the uncertainty principle, beta decay, the Fermi Theory, and modern physics. (YP)

  7. New precision measurements of free neutron beta decay with cold neutrons

    DOE PAGES

    Baeßler, Stefan; Bowman, James David; Penttilä, Seppo I.; ...

    2014-10-14

    Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the standard model. This study describes the free neutron beta decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and finally puts it into the context of other recent and planned measurements of neutron beta decay observables.

  8. Comparative study of beta-decay data for eight nuclides measured at the Physikalisch-Technische Bundesanstalt

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Fischbach, E.; Javorsek, D.; Jenkins, J. H.; Lee, R. H.; Nistor, J.; Scargle, J. D.

    2014-07-01

    We present the results of time-series analyses of data, kindly provided by the Physikalisch-Technische Bundesanstalt, concerning the beta-decays of Ag108, Ba133, Cs137, Eu152, Eu154, Kr85, Ra226, and Sr90. From measurements of the detector currents, we find evidence of annual oscillations (especially for Ra226), and for several solar r-mode oscillations. It is notable that the frequencies of these r-mode oscillations correspond to exactly the same sidereal rotation rate (12.08 year-1) that we have previously identified in r-mode oscillations detected in both Mt Wilson solar diameter data and Lomonosov Moscow State University Sr90 beta-decay data. Ba133 is found to be anomalous in that current measurements for this nuclide have a much larger variation (by 4 σ) than those of the other nuclides. It is interesting that analysis of variability measurements in the PTB files yields strong evidence for an oscillation for Ba133 but only weak evidence for Ra226.

  9. Study of Weak Interactions with Beta-Alpha Angular Correlations and the Positive Beta Decay of NITROGEN-18 and OXYGEN-14.

    NASA Astrophysics Data System (ADS)

    Hernandez, Ana Maria

    1982-03-01

    A (beta)-(alpha) angular correlation measuring device has been designed and constructed. The apparatus will be used in a future experiment to measure the (beta)(E(,0) = 5.455 MeV) and (alpha)(2.148 MeV) directional correlation in the decay of ('20)Na as a function of the (beta) energy. Two (alpha) detectors and sixteen telescopic (beta) detectors allow for the simultaneous measurement of (beta)-(alpha) coincidences at 0(DEGREES), 25(DEGREES), 45(DEGREES), 65(DEGREES), 90(DEGREES), 115(DEGREES), 135(DEGREES), and 180(DEGREES) and their symmetrical counterparts with respect to the 0(DEGREES) (--->) 180(DEGREES) direction. A circulating gas system transports the ('20)Na activity produced by the ('20)Ne(p,n)('20)Na reaction to a shielded counting area. The angular correlation effect to be measured is small and amounts to only about 1% of the main, isotropic component of the decay. The high symmetry of the apparatus as well as the use of appropriate geometrical corrections provide the necessary high accuracy. Adequate statistics may be obtained in reasonable times. In addition, two different simpler but interesting experiments were carried out; one is the (beta)('+) decay of ('18)Ne and the other is the (beta) decay of ('14)O. The ('18)Ne (--->) ('18)F (beta) decay was studied by measuring the ('18)F de-excitation (gamma) rays relative intensities. Compton suppression shielding and magnetic positron deflection were used in order to improve the (gamma) spectrum from the ('18)F de-excitation states. The intensity of the O('-) (1081 keV) de-excitation (gamma) ray relative to the 1042 keV de-excitation was found to be (2.97 (+OR -) 0.22) x 10('-2)%. An absolute (beta) branch I(,(beta)) = (2.14 (+OR-) 0.26) x 10('-3)% and ft = (0.99 (+OR-) 0.12) x 10('7) sec for the O('+) (--->) O('-) (beta) decay branch were deduced. This value together with the existing upper limit on the parity mixing of the O('+), O('-) doublet in ('18)F allow the evaluation of the strength of the PNO

  10. Beyond low beta-decay Q values

    SciTech Connect

    Mustonen, M. T.; Suhonen, J.

    2010-11-24

    Beta decays with low Q values can be utilized in the quest to determine the neutrino mass scale. This is being realized in two experiments, KATRIN and MARE, using tritium and {sup 187}Re, respectively. The beta-decay of {sup 187}Re had the lowest known Q value until 2005, when the beta decay of {sup 115}In to the first excited state of {sup 115}Sn was discovered in Gran Sasso underground laboratory. Last year two independent ion trap measurements confirmed that this decay breaks the former record by an order of magnitude.Our theoretical study on this tiny decay channel complemented the experimental effort by the JYFLTRAP group in Finland and HADES underground laboratory in Belgium. A significant discrepancy between the experimental and theoretical results was found. This might be explained by various atomic contributions known to grow larger as the Q value decreases. However, the traditional recipes for taking these effects into account break down on this new ultra-low Q value regime, providing new challenges for theorists on the borderline between nuclear and atomic physics.

  11. Production of 82Se enriched Zinc Selenide (ZnSe) crystals for the study of neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Dafinei, I.; Nagorny, S.; Pirro, S.; Cardani, L.; Clemenza, M.; Ferroni, F.; Laubenstein, M.; Nisi, S.; Pattavina, L.; Schaeffner, K.; di Vacri, M. L.; Boyarintsev, A.; Breslavskii, I.; Galkin, S.; Lalayants, A.; Rybalka, I.; Zvereva, V.; Enculescu, M.

    2017-10-01

    High purity Zinc Selenide (ZnSe) crystals are produced starting from elemental Zn and Se to be used for the search of the neutrinoless double beta decay (0νDBD) of 82Se. In order to increase the number of emitting nuclides, enriched 82Se is used. Dedicated production lines for the synthesis and conditioning of the Zn82Se powder in order to make it suitable for crystal growth were assembled compliant with radio-purity constraints specific to rare event physics experiments. Besides routine check of impurities concentration, high sensitivity measurements are made for radio-isotope concentrations in raw materials, reactants, consumables, ancillaries and intermediary products used for ZnSe crystals production. Indications are given on the crystals perfection and how it is achieved. Since very expensive isotopically enriched material (82Se) is used, a special attention is given for acquiring the maximum yield in the mass balance of all production stages. Production and certification protocols are presented and resulting ready-to-use Zn82Se crystals are described.

  12. 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.

  13. Current double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Giuliani, A.

    2005-01-01

    After an introduction about double beta decay and the deep connections between the lepton-violating channel and the neutrino properties, the most sensitive experimental approaches to the search for this rare nuclear transition are described. An overview of the experiments presently running is then given, with particular emphasis on the adopted techniques and their possible extrapolation to next-generation, higher-sensitivity experiments. The present situation about the experimental determination of the Majorana neutrino mass is presented and discussed.

  14. Study of CdMoO4 crystal for a neutrinoless double beta decay experiment with 116Cd and 100Mo nuclides

    NASA Astrophysics Data System (ADS)

    Xue, Ming-Xuan; Zhang, Yun-Long; Peng, Hai-Ping; Xu, Zi-Zong; Wang, Xiao-Lian

    2017-04-01

    The scintillation properties of a CdMoO4 crystal have been investigated experimentally. The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO4 crystal is a good candidate for an absorber for a bolometer readout, for both heat and scintillation signals. The results from Monte Carlo studies, taking the backgrounds from 2ν2β of and internal trace nuclides 214Bi and 208Tl into account, show that the expected sensitivity of a CdMoO4 bolometer for neutrinoless double beta decay experiments with an exposure of 100 kg·years is one order of magnitude higher than those of the current sets of the of and Supported by National Natural Science Foundation of China (11275199)

  15. Study of excited states of {sup 31}S through beta-decay of {sup 31}Cl for nucleosynthesis in ONe novae

    SciTech Connect

    Saastamoinen, A.; Jokinen, A.; Aeystoe, J.; Trache, L.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Banu, A.; Bentley, M. A.; Davinson, T.; Woods, P. J.

    2011-11-30

    We have produced an intense and pure beam of {sup 31}Cl with the MARS Separator at the Texas A and M University and studied {beta}-decay of {sup 31}Cl by implanting the beam into a novel detector setup, capable of measuring {beta}-delayed protons and {gamma}-rays simultaneously. From our data, we have established decay scheme of {sup 31}Cl, found resonance energies with 1 keV precision, have measured its half-life with under 1% accuracy, found its Isobar Analog State decay and by using the IMME obtained an improved mass excess for its ground state. In this contribution, a description of the used method along with selected preliminary experimental results are given and their relevance for novae nucleosynthesis discussed.

  16. Neutrinoless Double Beta Decay:

    NASA Astrophysics Data System (ADS)

    Miramonti, Lino

    0ν2β decay is a very powerful tool for probing the physics beyond the particle Standard Model. After the recent discovery of neutrino flavor oscillation, we know that neutrinos must have a mass (at least two of them). The 0ν2β decay discovery could fix the neutrino mass scale and its nature (Majorana particle). The unique characteristics of the Borexino detector and its Counting Test Facility (CTF) can be employed for high sensitivity studies of 116Cd 0ν2β decay: the CAMEO project. A first step foresees 24 enriched 116CdWO4 crystals for a total mass of 65 kg in the Counting Test Facility; then, 370 enriched 116CdWO4 crystals, for a total mass of 1 ton in the Borexino detector. Measurements of 116CdWO4 crystals and Monte Carlo simulations have shown that the CAMEO experiment sensitivity will be T1/20ν > 1026 y, for the 65 kg phase, and T1/20ν > 1027 y for the 1 ton phase; consequently the limit on the effective neutrino mass will be ≤ 60 meV, and ≤ 20 meV, respectively. This work is based upon the experiments performed by the INR (Kiev) (and from 1998 also by the University of Florence) at the Solotvina Underground Laboratory (Ukraine). The current status of 0ν2β, and future projects of 0ν2β decay research are also briefly reviewed.

  17. {beta} decay of {sup 95}Ag

    SciTech Connect

    Harissopulos, S.; Galanopoulos, S.; Skouras, L. D.; Doering, J.; Schmidt, K.; Gorska, M.; Grawe, H.; Hellstroem, M.; Kirchner, R.; Roeckl, E.; La Commara, M.; Mazzocchi, C.; Borcea, R.; Janas, Z.; Johnstone, I.P.; Schwengner, R.

    2005-08-01

    We studied the {beta}-decay properties of the N=Z+1 nucleus {sup 95}Ag by measuring {beta}-delayed {gamma} rays and {beta}-{gamma}-{gamma} coincidences with a plastic scintillator as {beta} detector and a Ge-detector array. The {sup 95}Ag nuclei were produced by means of the {sup 58}Ni({sup 40}Ca,p2n) reaction and separated with the GSI online mass separator. The previously reported level scheme of the {sup 95}Pd daughter nucleus was extended considerably. The deduced level scheme is compared with different shell-model calculations with or without breaking the {sup 100}Sn core.

  18. 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.

  19. Neutrino mass spectrum and future beta decay experiments

    NASA Astrophysics Data System (ADS)

    Farzan, Y.; Peres, O. L. G.; Smirnov, A. Yu.

    2001-09-01

    We study the discovery potential of future beta decay experiments on searches for the neutrino mass in the sub-eV range, and, in particular, KATRIN experiment with sensitivity m>0.3 eV. Effects of neutrino mass and mixing on the beta decay spectrum in the neutrino schemes which explain the solar and atmospheric neutrino data are discussed. The schemes which lead to observable effects contain one or two sets of quasi-degenerate states. Future beta decay measurements will allow to check the three-neutrino scheme with mass degeneracy, moreover, the possibility appears to measure the CP-violating Majorana phase. Effects in the four-neutrino schemes which can also explain the LSND data are strongly restricted by the results of Bugey and CHOOZ oscillation experiments: apart from bending of the spectrum and the shift of the end point one expects appearance of small kink of (<2%) size or suppressed tail after bending of the spectrum with rate below 2% of the expected rate for zero neutrino mass. We consider possible implications of future beta decay experiments for the neutrino mass spectrum, the determination of the absolute scale of neutrino mass and for establishing the nature of neutrinos. We show that beta decay measurements in combination with data from the oscillation and double beta decay experiments will allow to establish the structure of the scheme (hierarchical or non-hierarchical), the type of the hierarchy or ordering of states (normal or inverted) and to measure the relative CP-violating phase in the solar pair of states.

  20. Double beta decays and neutrino nuclear responses

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    1999-05-01

    Neutrinos (ν) beyond the standard theory are studied by investigating double beta decays (ββ). The present status of ββ studies at RCNP is briefly reported. The ββ decays on 100Mo and 48Ca are studied at the Oto Cosmo Observatory. The Oto observatory is a new underground laboratory with low Rn and cosmic-ray backgrounds. The sensitivities expected there are 0.5 ˜ 1 eV for the Majorana ν-mass, 10 -6 ˜ 10 -8 for the right-handed weak currents, 2˜4.10 -5 for the ν-Majoron coupling, and so on. Nuclear axial weak responses for ββ-ν are investigated by charge-exchange spin-flip nuclear reactions.

  1. A massive neutrino in nuclear beta decay

    SciTech Connect

    Norman, E.B.; Chan, Yuen-Dat; Garcia, A.; Lesko, K.T.; Larimer, R.M.; Stokstad, R.G.; Sur, B.; Zlimen, I. ); da Cruz, M.T.F. Sao Paulo Univ., SP . Inst. of Physics); Hindi, M.M. Tennessee Technological Univ., Cookeville, TN . Dept. of Physics); Wietfeld

    1992-08-01

    We have continued our studies of the p-spectrum of [sup 14]C using a germanium detector doped with [sup 14]C. There is a feature in the [beta]-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the [beta]-decay of [sup 14]C with a mass of 17[plus minus]1 keV and an emission probability of 1.26[plus minus]0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of [sup 55]Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the kink'' that has been observed in some recent beta spectral measurements is not a neutrino.

  2. A massive neutrino in nuclear beta decay

    SciTech Connect

    Norman, E.B.; Chan, Y. ); da Cruz, M.F. Physics Institute, University of Sao Paulo, Sao Paulo ); Garcia, A. ); Hindi, M.M. Physics Department, Tennessee Technological University, Cookeville, Tennessee ); Lesko, K.T.; Larimer, R.; Stokstad, R.G.; Sur, B. ); Wietfeldt, F.E. Physics Department, University of California, Berkeley, California ); Zlimen, I. (Nuclear Science Division, Lawrence Berke

    1992-02-01

    We have continued our studies of the [beta]-spectrum of [sup 14]C using a germanium detector doped with [sup 14]C. There is a feature in the [beta]-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the [beta]-decay of [sup 14]C with a mass of 17[plus minus]1 keV and an emission probability of 1.26[plus minus]0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of [sup 55]Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the kink'' that has been observed in some recent beta spectral measurements is not a neutrino.

  3. A massive neutrino in nuclear beta decay?

    SciTech Connect

    Norman, E.B.; Chan, Yuen-Dat; Garcia, A.; Lesko, K.T.; Larimer, R.M.; Stokstad, R.G. Sur, B.; Zlimen, I.; da Cruz, M.T.F. |; Hindi, M.M. |; Wietfeldt, F.E. |

    1992-09-01

    We have continued our studies of the {beta}-spectrum of {sup 14}C using a germanium detector doped with {sup l4}C. There is a feature in the {beta}-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the {beta}-decay of {sup 14}C with a mass of 17{plus_minus}1 keV and an emission probability of 1.26{plus_minus}0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of {sup 55}Fe and find no indication of the emission of a {sup 17}-keV neutrino. We conclude that the origin of the ``kink`` that has been observed in some recent beta spectral measurements is not a neutrino.

  4. A massive neutrino in nuclear beta decay?

    SciTech Connect

    Norman, E.B.; Chan, Yuen-Dat; Garcia, A.; Lesko, K.T.; Larimer, R.M.; Stokstad, R.G.; Sur, B.; Zlimen, I.; da Cruz, M.T.F. |; Hindi, M.M. |; Wietfeldt, F.E.

    1992-08-01

    We have continued our studies of the p-spectrum of {sup 14}C using a germanium detector doped with {sup 14}C. There is a feature in the {beta}-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the {beta}-decay of {sup 14}C with a mass of 17{plus_minus}1 keV and an emission probability of 1.26{plus_minus}0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of {sup 55}Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the ``kink`` that has been observed in some recent beta spectral measurements is not a neutrino.

  5. A massive neutrino in nuclear beta decay

    SciTech Connect

    Norman, E.B.; Chan, Yuen-Dat; Garcia, A.; Lesko, K.T.; Larimer, R.M.; Stokstad, R.G. Sur, B.; Zlimen, I. ); da Cruz, M.T.F. University of Sao Paulo, Sao Paulo, Brazil . Physics Institute); Hindi, M.M. Tennessee Technological Univ., Cookeville, TN (United Stat

    1992-09-01

    We have continued our studies of the [beta]-spectrum of [sup 14]C using a germanium detector doped with [sup l4]C. There is a feature in the [beta]-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the [beta]-decay of [sup 14]C with a mass of 17[plus minus]1 keV and an emission probability of 1.26[plus minus]0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of [sup 55]Fe and find no indication of the emission of a [sup 17]-keV neutrino. We conclude that the origin of the kink'' that has been observed in some recent beta spectral measurements is not a neutrino.

  6. {beta} decay of {sup 32}Na

    SciTech Connect

    Mattoon, C. M.; Sarazin, F.; Hackman, G.; Ball, G. C.; Chakrawarthy, R. S.; Scraggs, H. C.; Smith, M. B.; Cunningham, E. S.; Walker, P. M.; Austin, R. A. E.; Finlay, P.; Grinyer, G. F.; Hyland, B.; Phillips, A. A.; Schumaker, M. A.; Svensson, C. E.; Garrett, P. E.; Koopmans, K. A.; Waddington, J. C.; Washbrook, B.

    2007-01-15

    The {beta}-decay of {sup 32}Na has been studied using {beta}-{gamma} coincidences. New transitions and levels are tentatively placed in the level scheme of {sup 32}Mg from an analysis of {gamma}-{gamma} and {beta}-{gamma}-{gamma} coincidences. The observation of the indirect feeding of the 2321 keV state in {sup 32}Mg removes some restrictions previously placed on the spin assignment for this state. No evidence of a state at 2117 keV in {sup 32}Mg is found. Previously unobserved weak transitions up to 5.4 MeV were recorded but could not be placed in the decay scheme of {sup 32}Na.

  7. 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.

  8. A binding energy study of the Atomic Mass Evaluation 2012 and an updated beta-decay study of neutron-rich 74Cu

    NASA Astrophysics Data System (ADS)

    Tracy, James L., Jr.

    A study of ground state binding energy values listed in the Atomic Mass Evaluation 2012 (AME2012) using an interpretive approach, as opposed to the exploratory methods of previous models, is presented. This model is based on a postulate requiring all protons to pair with available neutrons to form bound alpha clusters as the ground state for an N = Z core upon which excess neutrons are added. For each core, the trend of the binding energy as a function of excess neutrons in the isotopic chain can be fit with a three-term quadratic function. The quadratic parameter reveals a smooth decaying exponential function. By re-envisioning the determination of mass excess, the constant-term fit parameters, representing N = Z nuclei, reveal a near-symmetry around Z = 50. The linear fit parameters exhibit trends which are linear functions of core size. A neutron drip-line prediction is compared against current models. By considering the possibility of an alpha-cluster core, a new ground-state structure grouping scheme is presented; nucleon-nucleon pairing is shown to have a greater role in level filling. This model, referred to as the Alpha-Deuteron-Neutron Model, yields promising first results when considering root-mean-square variances from the AME2012. The beta-decay of the neutron-rich isotope 74Cu has been studied using three high-purity Germanium clover detectors at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. A high-resolution mass separator greatly improved the purity of the 74Cu beam by removing isobaric contaminants, thus allowing decay through its isobar chain to the stable 74Ge at the center of the LeRIBSS detector array without any decay chain member dominating. Using coincidence gating techniques, 121 gamma-rays associated with 74Cu were isolated from the collective singles spectrum. Eighty-seven of these were placed in an expanded level scheme, and updated beta-feeding level intensities and log( ft) values are presented based on

  9. Constraining neutrinoless double-beta decay matrix elements

    NASA Astrophysics Data System (ADS)

    Menendez, Javier

    2015-10-01

    Neutrinoless double-beta decay, if detected, would proof the Majorana nature of neutrinos. The decay lifetime is governed by the absolute neutrino masses and the nuclear matrix elements of the transition. Therefore accurate matrix elements are needed to asses the sensitivity of current and future experiments, and to determine the absolute neutrino masses and hierarchy with neutrinoless double-beta decay. However, present nuclear matrix element calculations show significant uncertainties. These affect the nuclear structure description of the mother and daughter nuclei, and also the treatment of the transition operator. In this talk I cover recent progress on neutrinoless double-beta decay nuclear matrix element calculations. On the one hand, I discuss the role of the size of the configuration space and of nuclear structure correlations. By comparing matrix elements obtained with different nuclear structure approaches and interactions, optimal strategies for improving the nuclear structure calculations capturing the most important correlations are identified. On the other hand, I describe first attempts to include two-body currents in the double-beta decay operator. They can be related to the ``quenching'' of the spin-isospin operator empirically found in nuclear structure studies.

  10. Experimental setup and commissioning baseline study in search of time-variations in beta-decay half-lives

    NASA Astrophysics Data System (ADS)

    Goddard, Braden; Hitt, George W.; Solodov, Alexander A.; Bridi, Dorian; Isakovic, A. F.; El-Khazali, Reyad; Abulail, Ayman

    2016-03-01

    Recently there have been a number of investigations into whether the decay constant of a radioactive isotope can be influenced by external factors, such as the Earth-Sun distance or Solar flare activity. Positive claims suggest that annual oscillations of ~0.1% and accelerations of ~0.4% in the relative activity of beta-emitters coincide with the Earth-Sun distance and solar flare activity, respectively. Results from replication experiments have so far been conflicting. The main criticism of the measurements used to trace and quantify these effects is that the data is of poor quality or limited in scope. Data have often been collected as part of short duration weekly calibration measurements, measured with a single type of low precision detector, only using one isotope, and having no environmental conditions information (temperature, pressure, humidity) accompanying the radiation measurements. This paper describes the setup of a series of counting experiments commissioned for addressing these criticisms. Six dedicated detector systems (four different types) measuring six different isotopes (14C, 54Mn, 60Co, 90Sr, 204Tl, and 226Ra) have been continuously collecting source activity synchronously with environmental data for a period of one month (April 2014). The results of this baseline commissioning study show that there are correlations between activity and environmental conditions for some detector types which are then quantified. The results also show that the one sigma counting uncertainties in all the detectors are less than 0.024% for a given 24 h period. After accounting for propagated uncertainties from corrections against correlations with environmental data, the ability to resolve 0.1% activity changes varies, from 8 min to 1.6 days, depending on the specific detector. All six experiments therefore, will have sufficient precision over the upcoming year to scrutinize claims of both annual activity oscillations and solar flare activity changes.

  11. Intermediate Nuclear Structure for 2v 2{beta} Decay of {sup 48}Ca Studied by (p, n) and (n, p) Reactions at 300 MeV

    SciTech Connect

    Sakai, H.; Yako, K.

    2009-08-26

    Angular distributions of the double differential cross sections for the {sup 48}Ca(p,n) and the {sup 48}Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) transition strengths. In the (n, p) spectrum beyond 8 MeV excitation energy extra B(GT{sup +}) strengths which are not predicted by the shell model calculation. This extra B(GT{sup +}) strengths significantly contribute to the nuclear matrix element of the 2v2{beta}-decay.

  12. Deformed quasiparticle random phase approximation formalism for single- and two-neutrino double {beta} decay

    SciTech Connect

    Alvarez-Rodriguez, R.; Sarriguren, P.; Moya de Guerra, E.; Pacearescu, L.; Faessler, Amand; Simkovic, F.

    2004-12-01

    We use a deformed quasiparticle random phase approximation formalism to describe simultaneously the energy distributions of the single {beta} Gamow-Teller strength and the two-neutrino double {beta} decay matrix elements. Calculations are performed in a series of double {beta} decay partners with A=48, 76, 82, 96, 100, 116, 128, 130, 136, and 150, using deformed Woods-Saxon potentials and deformed Skyrme Hartree-Fock mean fields. The formalism includes a quasiparticle deformed basis and residual spin-isospin forces in the particle-hole and particle-particle channels. We discuss the sensitivity of the parent and daughter Gamow-Teller strength distributions in single {beta} decay, as well as the sensitivity of the double {beta} decay matrix elements to the deformed mean field and to the residual interactions. Nuclear deformation is found to be a mechanism of suppression of the two-neutrino double {beta} decay. The double {beta} decay matrix elements are found to have maximum values for about equal deformations of parent and daughter nuclei. They decrease rapidly when differences in deformations increase. We remark on the importance of a proper simultaneous description of both double {beta} decay and single Gamow-Teller strength distributions. Finally, we conclude that for further progress in the field, it would be useful to improve and complete the experimental information on the studied Gamow-Teller strengths and nuclear deformations.

  13. Why search for double beta decay

    SciTech Connect

    Kayser, B.

    1988-04-20

    Searching for neutrinoless double beta decay is the only known practical method for trying to determine whether neutrinos are their own antiparticles. The theoretical motivation for supposing that they may indeed be their own antiparticles is described. The reason that it is so difficult to ascertain experimentally whether they are or are not is explained, as is the special sensitivity of neutrinoless double beta decay. The potential implications of the observation of this reaction for neutrino mass and for the physics of neutrinos is discussed.

  14. Problems and progress in tritium beta decay

    SciTech Connect

    Balke, B.; Fackler, O.; Mugge, M.; White, R.

    1988-04-01

    It has been nearly eight years since the group led by Lubimov first saw evidence for a finite neutrino mass in the tritium beta decay spectrum. Their measurement provided a great stimulus to the field; the number of experiments currently underway reflects the significance of their claim. The fact that further data are only now beginning to appear reflects the difficulty of this measurement. As an introduction to related papers in these proceedings, we briefly consider the key elements involved in neutrino-mass measurements using tritium beta decay and list the experiments currently underway in the field. 5 refs., 1 tab.

  15. Scintillating bolometers for Double Beta Decay search

    NASA Astrophysics Data System (ADS)

    Gironi, L.

    2010-05-01

    In the field of Double Beta Decay (DBD) searches, the use of high resolution detectors in which background can be actively discriminated is very appealing. Scintillating bolometers containing a Double Beta Decay emitter can largely fulfill this very interesting possibility. In this paper we present the latest results obtained with CdWO4 and CaMoO4 crystals. Moreover we report, for the first time, a very interesting feature of CaMoO4 bolometers: the possibility to discriminate β-γ events from those induced by α particles thanks to different thermal pulse shape.

  16. The double-beta decay: Theoretical challenges

    SciTech Connect

    Horoi, Mihai

    2012-11-20

    Neutrinoless double beta decay is a unique process that could reveal physics beyond the Standard Model of particle physics namely, if observed, it would prove that neutrinos are Majorana particles. In addition, it could provide information regarding the neutrino masses and their hierarchy, provided that reliable nuclear matrix elements can be obtained. The two neutrino double beta decay is an associate process that is allowed by the Standard Model, and it was observed for about ten nuclei. The present contribution gives a brief review of the theoretical challenges associated with these two process, emphasizing the reliable calculation of the associated nuclear matrix elements.

  17. Collective and noncollective states in {sup 116}Cd studied via the {beta} decays of {sup 116}Ag{sup m1,m2,gs}

    SciTech Connect

    Batchelder, J. C.; Carter, H. K.; Spejewski, E. H.; Garrett, P. E.; Green, K. L.; Rykaczewski, K. P.; Bilheux, J.-C.; Stracener, D. W.; Bingham, C. R.; Fong, D.; Hamilton, J. H.; Hwang, J. K.; Ramayya, A. V.; Grzywacz, R.; Larochelle, Y.; Tantawy, M. N.; Hartley, D. J.; Krolas, W.

    2009-11-15

    We have reinvestigated the {beta} decay of the three isomers of {sup 116}Ag at the Holifield Radioactive Ion Beam Facility (HRIBF). Through the use of half-life information, we have been able to construct individual decay schemes for each isomer and correct what was a puzzling inconsistency with the published data, namely the {beta} feeding of 2{sup +} states by a 5{sup +} isomer. Our results indicate that the feeding of these levels arises from a 3{sup +} isomer in {sup 116}Ag. A total of 271{gamma}-ray transitions (159 new) were assigned to 148 levels (94 new) from the {beta} decay of {sup 116}Ag{sup m1,m2,gs}. Significant deviations are observed from IBM-2 calculations for the decay of the 0{sup +} and 2{sup +} members of the previously assigned three-phonon quintuplet. Candidate states for the quadrupole-octupole quintuplet states and {pi}g{sub 9/2}-{pi}p{sub 1/2}, {pi}g{sub 9/2}-{pi}p{sub 3/2}, {nu}h{sub 11/2}-{nu}s{sub 1/2}, {nu}h{sub 11/2}-{nu}d{sub 3/2}, and {nu}h{sub 11/2}-{nu}d{sub 5/2} broken-pair states are assigned.

  18. The Beta Decay of 32Cl

    NASA Astrophysics Data System (ADS)

    Aboud, E.; Wrede, C.; Bennett, M. B.; Liddick, S. N.; Pérez-Loureiro, D.; Brown, B. A.; Fry, C.; Glassman, B. E.; Langer, C.; Larson, N. R.; Ong, W.; Prokop, C. J.; Schwartz, S. B.; Suchyta, S.; Xu, X.; Bardayan, D. W.; Meisel, Z.; O'Malley, P. D.; Chen, A. A.; McNeice, E. I.; Walters, M.; Chipps, K. A.; Pain, S. D.; Thompson, P.

    2016-09-01

    32Cl is a neutron-deficient isotope with a β-decay half-life of 298 ms and a spin and parity of 1+. It lies close to stability; therefore it can be produced in large quantities at rare isotope beam facilities making its decay relatively straightforward to study. Previous measurements of 32Cl β-delayed γ rays have yielded β-decay schemes including allowed β decay transitions. In this study, we present the results of a more sensitive measurement of 32Cl beta decay using the CloverShare array of high-purity germanium detectors at the National Superconducting Cyclotron Laboratory. By acquiring the highest-resolution and highest-statistics 32Cl β-delayed γ ray data set to date, this experiment has allowed for the observation of several γ ray transitions that had only been previously observed in nuclear reaction experiments. A more complete decay scheme has been constructed, including the first observation of forbidden Gamow-Teller transitions in 32Cl β decay.

  19. Thermonuclear runaways investigated using drip line beta decays

    NASA Astrophysics Data System (ADS)

    Wrede, Christopher

    2016-09-01

    In close binary star systems, mass transfer onto the surface of a white dwarf or neutron star can lead to spectacular periodic emissions including classical novae and x-ray bursts. Accurate nuclear reaction rates are needed to model energy generation and nucleosynthesis in these thermonuclear runaways enabling meaningful comparisons to observations. An experimental program has been established at the National Superconducting Cyclotron Laboratory to constrain the most influential nuclear physics uncertainties using the beta decays of nuclides adjacent to the proton drip line. In particular, the beta decays of 20Mg, 26P, and 31Cl have been used to investigate the 15O(α,γ)19Ne, 25Al(p,γ)26Si, and 30P(p,γ)31S reaction rates, respectively. These studies relate to the shapes of x-ray burst light curves, the production of the radionuclide 26Al in the Milky Way, and the identification of presolar nova grains in meteoritic material.

  20. {beta}-decay of {sup 23}Al and nova nucleosynthesis

    SciTech Connect

    Saastamoinen, A.; Jokinen, A.; Aeystoe, J.; Trache, L.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Banu, A.; Bentley, M. A.; Jenkins, D. G.; Davinson, T.; Woods, P. J.

    2010-11-24

    We have studied the {beta}-decay of {sup 23}Al with a novel detector setup at the focal plane of the MARS separator at the Texas A and M University to resolve existing controversies about the proton intensities of the IAS in {sup 23}Mg and to determine the absolute proton branching ratios by combining our results to the latest {gamma}-decay data. Experimental technique, results and the relevance for nova nucleosynthesis are discussed.

  1. 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}

  2. Double beta decay: recent developments and projections

    SciTech Connect

    Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1983-08-01

    A report of recent events in both theoretical and experimental aspects of double beta decay is given. General theoretical considerations, recent developments in nuclear structure theory, geochronological determinations of half lives and ratios as well as laboratory experiments are discussed with emphasis on the past three years. Some projections are given. 28 references.

  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. Measuring pion beta decay with high-energy pion beams

    SciTech Connect

    McFarlane, W.K. Temple Univ., Philadelphia, PA ); Hoffman, C.M. )

    1993-01-01

    Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay [pi][sup +] [yields] [pi][sup 0]e[sup +]v[epsilon] is predicted by the Standard Model (SM) to be R([pi][sup +] [yields] [pi][sup 0]e[sup +]v[epsilon]) = 0.3999[plus minus]0.0005 s[sup [minus]1]. The best experimental number, obtained using in-flight decays, is R([pi][sup +] [yields] [pi][sup 0]e[sup +]v[epsilon]) = 0.394 [plus minus] 0.015 s[sup [minus]1]. A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required.

  5. Measuring pion beta decay with high-energy pion beams

    SciTech Connect

    McFarlane, W.K. |; Hoffman, C.M.

    1993-02-01

    Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay {pi}{sup +} {yields} {pi}{sup 0}e{sup +}v{epsilon} is predicted by the Standard Model (SM) to be R({pi}{sup +} {yields} {pi}{sup 0}e{sup +}v{epsilon}) = 0.3999{plus_minus}0.0005 s{sup {minus}1}. The best experimental number, obtained using in-flight decays, is R({pi}{sup +} {yields} {pi}{sup 0}e{sup +}v{epsilon}) = 0.394 {plus_minus} 0.015 s{sup {minus}1}. A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required.

  6. Beta-decay of {sup 40}Ti and its implication for solar-neutrino detection

    SciTech Connect

    Liu, W.; Hellstroem, M.; Collatz, R.; Benlliure, J.; Gil, D. Cortina; Farget, F.; Grawe, H.; Hu, Z.; Iwasa, N.; Roeckl, E.; Chulkov, L.; Pfuetzner, M.; Piechaczek, A.; Raabe, R.; Reusen, I.; Vancraeynest, G.; Woehr, A.

    1998-12-21

    The {beta}-decay of {sup 40}Ti was studied by measuring the {beta}-decayed proton- and {gamma}-emission. The half-life for {sup 40}Ti was determined to be 54(2) ms. The experimental {beta}-decay strength distribution is compared with shell-model calculations and results from other experiments. Based on the experimental {sup 40}Ti{beta}-decay strength, the neutrino absorption cross section and induced neutrino event rates for {sup 40}Ar were determined to be 14.3(3)x10{sup -43} cm{sup 2} and 9.4{+-}0.2(stat.){sub -1.6}{sup +13}(syst.) SNU, respectively.

  7. Double beta decay: yesterday, today, tomorrow

    SciTech Connect

    Fiorini, Ettore

    2011-12-16

    After a brief introduction on the main features of Double Beta Decay (DBD) and on its origin, its importance is stressed in view of the recent results of experiments on neutrino oscillations. The present experimental situation is reported with special reference to direct experiments and to the comparison of their results with theory. The expectations of the future experiments aiming to reach the sensitivity indicated by neutrino oscillations in the inverse hierarchy hypothesis are discussed.

  8. Forbidden beta decays of {sup 96}Zr and {sup 115}In: Implications for neutrino physics

    SciTech Connect

    Mustonen, M. T.; Suhonen, J.

    2009-11-09

    We summarize our theoretical results for two nuclides of interest for the double-beta decay and neutrino mass studies: {sup 96}Zr and {sup 115}In.The double-beta decay of {sup 96}Zr competes with three highly-forbidden beta-decay channels. Our microscopic nuclear-structure calculations imply that the half-life of the first-order beta-decay channels is an order of magnitude longer than that of the double-beta decay.In the work of C. T. Cattadori et al. it was discovered that {sup 115}In can beta decay to the first excited state of {sup 115}Sn. It was also suggested that this decay might provide a supplementary way of accessing the neutrino mass. The recent half-life measurement carried out in the underground laboratory HADES confirms the existence and refines the half-life of this decay channel. At the same time the precision mass measurements made at the University of Jyvaeskylae yield the record-setting ultra-low Q value of 0.35(17) keV. Our theoretical analysis of this decay suggests that atomic effects could play an important role in relating the measured half-life to the measured Q value.

  9. Double Beta Decays and Neutrinos - Experiments and MOON -

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    2008-01-01

    This is a brief review of the present and future experiments of neutrino-less double beta decays (0νββ) and the MOON (Mo Observatory Of Neutrinos) project. High sensitivity 0νββ experiments are unique and realistic probes for studying the Majorana nature of neutrinos and the absolute mass scale as suggested by neutrino oscillation experiments. MOON aims at spectroscopic 0νββ studies with the ν-mass sensitivity of 100-30 meV by means of a super ensemble of multilayer modules of scintillator plates and tracking detector planes.

  10. 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.

  11. 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.

  12. Double Beta Decay in Gauge Theories

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.

    2002-09-01

    Neutrinoless double beta decay is a very important process both from the particle and nuclear physics point of view. From the elementary particle point of view it pops up in almost every model, giving rise among others to the following mechanisms: a) The traditional contributions like the light neutrino mass mechanism as well as the jL - jR leptonic interference (λ and η terms). b) The exotic R-parity violating supersymmetric (SUSY) contributions. From the nuclear physics point of view it is challenging, because: 1) The nuclei, which can undergo double beta decay, have complicated nuclear structure. 2) The energetically allowed transitions are suppressed (exhaust a small part of all the strength). 3) Since in some mechanisms the intermediate particles are very heavy one must cope with the short distance behavior of the transition operators. 4) The intermediate momenta involved are quite high and one has to consider momentum dependent terms of the nucleon current. Taking the above effects into account from the experimental limits on the interesting nuclei A = 76, 82, 96, 100, 116, 128, 130, 136 and 150, we have extracted new limits on the various lepton violating parameters. In particular we get a stringent limit on the R-parity violating parameter λ '111 < 4.0 × 10-4.

  13. 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.

  14. Neutrino oscillation constraints on neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Bilenky, S. M.; Giunti, C.; Kim, C. W.; Monteno, M.

    1998-06-01

    We have studied the constraints imposed by the results of neutrino oscillation experiments on the effective Majorana mass \\|\\| that characterizes the contribution of Majorana neutrino masses to the matrix element of neutrinoless double-beta decay. We have shown that in a general scheme with three Majorana neutrinos and a hierarchy of neutrino masses (which corresponds to the standard seesaw mechanism) the results of neutrino oscillation experiments imply rather strong constraints on the parameter \\|\\|. From the results of the first reactor long-baseline experiment CHOOZ and the Bugey experiment it follows that \\|\\|<~3×10-2 eV if Δm2<~2 eV2 (Δm2 is the largest mass-squared difference). Hence, we conclude that the observation of neutrinoless double-beta decay with a probability that corresponds to \\|\\|>~10-1 eV would be a signal for a nonhierarchical neutrino mass spectrum and/or nonstandard mechanisms of lepton number violation.

  15. NuDot: Search for neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Santana, Jesse

    2015-10-01

    NuDot is a prototype, liquid scintillator detector, to demonstrate that the separation of directional Cherenkov light from isotropic scintillation light is possible using sub-nanosecond photodetectors. NuDot is currently being tested on a small scale before ramping up to a one-metric ton prototype in the next three years. A proof-of-concept setup for separating the light as well as calibrating the PMTs' timing has been designed. The setup consist of two LEDs, the first of which will mimic the cherenkov light while the second represents the scintillating light. NuDot's main application is the search for neutrinoless double beta decay, but it could also be used to reduce backgrounds in studies of geo-neutrinos, solar neutrinos, supernovae neutrinos and neutrino interactions. By being sensitive to the Cherenkov light a detector will have directionality for events and increase it's energy resolution- these two effects can provide methods to veto backgrounds- which then allow for a better analysis of rare phenomena such as neutrinoless double beta decay.

  16. 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.

  17. Self-consistent approach to beta decay and delayed neutron emission

    NASA Astrophysics Data System (ADS)

    Borzov, I. N.

    2016-11-01

    A brief overview of the recent self-consistent studies of nuclear beta decay is given including the relativistic quasi-particle random-phase approximation or QRPA and Finite Amplitude Method. The results of our self-consistent continuum QRPA model based on the density functional description of the ground states are presented. They are in a good agreement with the recent experimental beta-decay half-lives and delayed neutron emission branchings for the nuclei approaching (and beyond) the neutron closed shells N = 50 near 78Ni and N = 82 near 132Sn. A comparison with the recent calculations from relativistic QRPA model, Finite Amplitude Method and semi-microscopic finite-range droplet model is performed. An importance of the quasi-particle phonon coupling is stressed for the description of the beta decay and delayed multi-neutron emission rates. A strategy of extending our approach to the deformed nuclei and the open problems are discussed.

  18. Self-consistent approach to beta decay and delayed neutron emission

    SciTech Connect

    Borzov, I. N.

    2016-11-15

    A brief overview of the recent self-consistent studies of nuclear beta decay is given including the relativistic quasi-particle random-phase approximation or QRPA and Finite Amplitude Method. The results of our self-consistent continuum QRPA model based on the density functional description of the ground states are presented. They are in a good agreement with the recent experimental beta-decay half-lives and delayed neutron emission branchings for the nuclei approaching (and beyond) the neutron closed shells N = 50 near {sup 78}Ni and N = 82 near {sup 132}Sn. A comparison with the recent calculations from relativistic QRPA model, Finite Amplitude Method and semi-microscopic finite-range droplet model is performed. An importance of the quasi-particle phonon coupling is stressed for the description of the beta decay and delayed multi-neutron emission rates. A strategy of extending our approach to the deformed nuclei and the open problems are discussed.

  19. Nuclear matrix elements of the double beta decay for mass around 80

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Naotaka; Higashiyama, Koji; Teruya, Eri

    2014-09-01

    In nature there are 30 kinds of nuclei which are expected to have double beta decays. Among them ten nuclei are actually observed for the neutrino double beta decays. Still no observation is made for the neutrinoless double beta decays (0 νββ) . The 0 νββ decay is expected to occur only when neutrinos have masses and they are Majorana particles. In that respect observation of 0 νββ is to determine whether neutrinos are Majorana particles or not. In theoretical side in order to estimate the half life of 0 νββ determination of the nuclear matrix elements are essential. They were calculated in many theoretical frameworks, but the results are not consistent in various models. In this study we carry out shell model calculations for 82Se and 82Kr nuclei. After obtaining the wavefunctions, we calculate the nuclear matrix elements. For comparison we make pair truncated shell model calculations.

  20. Double beta decays of 100Mo and molybdenum observatory of neutrinos

    NASA Astrophysics Data System (ADS)

    Ejiri, H.; Engel, J.; Fushimi, K.; Hayashi, K.; Hazama, R.; Kishimoto, T.; Krastev, P.; Kudomi, N.; Kume, K.; Kuramoto, H.; Matsuoka, K.; Robertson, R. G. H.; Takahisa, K.; Yoshida, S.

    2002-07-01

    Exclusive measurements of neutrino-less double beta decays(0νββ) of 100Mo were made by means of ELEGANT V. The present status of the double beta decay experiment with ELEGANT V is presented. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on half-lives for 0νββ B and 0νββ. The multiton 100Mo detector, coincidence studies of correlated ββ from 0νββ, is now under development to study the neutrino mass with a sensitivity of ˜ 0.03eV.

  1. Neutrinos by double beta decays from 100Mo and nuclear spin-isospin responses

    NASA Astrophysics Data System (ADS)

    Kudomi, N.; Ejiri, H.; Fushimi, K.; Hayashi, K.; Kishimoto, T.; Komori, M.; Kume, K.; Kuramoto, H.; Matsuoka, K.; Ohsumi, H.; Takahisa, K.; Umehara, S.; Yoshida, S.

    2001-06-01

    Spectroscopic studies of neutrino-less double beta decays (0νββ) of 100Mo were made by means of ELEGANT V. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on the half-life of T1/2 for the 0νββ and the effective Majorana neutrino mass of <2.1 eV(90%C.L.). Spin-isospin responses for neutrinos associated with ββ of 100Mo are discussed. A perspective of double beta decay of 100Mo and a possible proposal of MOON are discussed. .

  2. MOON (Mo Observatory Of Neutrinos) for double beta decay

    NASA Astrophysics Data System (ADS)

    Nomachi, M.; Doe, P.; Ejiri, H.; Elliott, S. R.; Engel, J.; Finger, M.; Formaggio, J. A.; Fushimi, K.; Gehman, V.; Gorin, A.; Greenfield, M.; Hazama, R.; Ichihara, K.; Ikegami, Y.; Ishii, H.; Itahashi, T.; Kavitov, P.; Kekelidze, V.; Kuroda, K.; Kutsalo, V.; Manouilov, I.; Matsuoka, K.; Nakamura, H.; Ogama, T.; Para, A.; Rielage, K.; Rjazantsev, A.; Robertson, R. G. H.; Shichijo, Y.; Shima, T.; Shimada, Y.; Shirkov, G.; Sissakian, A.; Sugaya, Y.; Titov, A.; Vatulin, V.; Vilches, O. E.; Voronov, V.; Wilkerson, J. F.; Will, D. I.; Yoshida, S.

    2005-01-01

    The MOON (Molybdenum Observatory Of Neutrinos) project aims at studies of double beta decays with a high sensitivity of ˜0.03 eV and real-time studies of low-energy solar neutrinos. Two β rays from 100Mo are measured in coincidence for the 0νββ studies. The inverse β rays from solar neutrino captures of 100Mo are measured in delayed coincidence with the following β decay of 100Tc. Measurements with good energy resolution and good position resolution enable one to select true signals. A prototype MOON detector (MOON 1) is now under development. The present report describes briefly the outline of the MOON project and the status of MOON 1.

  3. Beta decay rates of neutron-rich nuclei

    SciTech Connect

    Marketin, Tomislav; Huther, Lutz; Martínez-Pinedo, Gabriel

    2015-10-15

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei.

  4. Optical pumping for nuclear beta decay

    NASA Astrophysics Data System (ADS)

    Behr, J. A.; Smale, S.; Craiciu, I.; Vantyghem, A.; Gorelov, A.; Anholm, M.; Behling, R. S.; Fenker, B.; Melconian, D.; Gwinner, G.; Friesen, D.

    2013-05-01

    For nuclear beta decay experiments to test the standard model, we must produce laser-cooled, polarized atoms with vector polarization of at least 99.9%, with knowledge of the polarization from atomic observables at 0.1% accuracy. We cycle on and off an AC MOT, and optically pump 37K atoms for 2 ms with trap off. We use circularly polarized light on the 4S1/2 --> 4P1/2 transition, using RF sidebands on a diode laser to excite transitions from both F=1 and F=2 ground states. We test techniques with stable 41K atoms, which have very similar hyperfine splitting to 37K. Optical pumping techniques include flipping spin state with liquid crystal variable retarders, 0.25 mm thick SiC substrate mirrors in front of the beta detectors, combining 769.9 D1 and 766.5 nm D2 with an angle-tuned narrow bandpass filter, relieving stress from conflat-compatible windows to minimize birefringence, and shifting the frequency of the light with the spin flips to compensate for Zeeman shifts. We must avoid coherent population trapping effects. The polarization is measured by the time dependence of the excited state population after optical pumping light is applied, probed by measuring fluorescence and by nonresonant photoionization. Supported by NSERC, NRC through TRIUMF.

  5. Neutrinoless double beta decay and neutrino mass

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    The observation of neutrinoless double beta decay (DBD) will have important consequences. First it will signal that lepton number is not conserved and the neutrinos are Majorana particles. Second, it represents our best hope for determining the absolute neutrino mass scale at the level of a few tens of meV. To achieve the last goal, however, certain hurdles have to be overcome involving particle, nuclear and experimental physics. Particle physics is important since it provides the mechanisms for neutrinoless DBD. In this review, we emphasize the light neutrino mass mechanism. Nuclear physics is important for extracting the useful information from the data. One must accurately evaluate the relevant nuclear matrix elements (NMEs), a formidable task. To this end, we review the recently developed sophisticated nuclear structure approaches, employing different methods and techniques of calculation. We also examine the question of quenching of the axial vector coupling constant, which may have important consequences on the size of the NMEs. From an experimental point of view it is challenging, since the life times are extremely long and one has to fight against formidable backgrounds. One needs large isotopically enriched sources and detectors with good energy resolution and very low background.

  6. Electron Capture Reactions and Beta Decays in Steller Environments

    SciTech Connect

    Suzuki, T.; Mao, H.; Honma, M.; Yoshida, T.; Kajino, T.; Otsuka, T.

    2011-10-28

    Electron capture reactions on Ni and Co isotopes are investigated by shell model calculations in steller environments. The capture rates depend sensitively on the distribution of the Gamow-Teller (GT) strength. The capture rates obtained by using GXPF1J Hamiltonian for fp-shell are found to be consistent with the rates obtained from experimental GT strength in {sup 58}Ni and {sup 60}Ni. Capture rates in Co isotopes, where there were large discrepancies among previous calculations, are also investigated. Beta decays of the N = 126 isotones are studied by shell model calculations taking into account both the GT and first-forbidden (FF) transitions. The FF transitions are found to be important to reduce the half-lives by twice to several times of those by the GT contributions only. Implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis are discussed for various astrophysical conditions.

  7. Beta-decay branching ratios of 62Ga

    NASA Astrophysics Data System (ADS)

    Bey, A.; Blank, B.; Canchel, G.; Dossat, C.; Giovinazzo, J.; Matea, I.; Elomaa, V.-V.; Eronen, T.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Moore, I.; Penttilä, H.; Rinta-Antila, S.; Saastamoinen, A.; Sonoda, T.; Äystö, J.; Adimi, N.; de France, G.; Thomas, J.-C.; Voltolini, G.; Chaventré, T.

    2008-05-01

    Beta-decay branching ratios of 62Ga have been measured at the IGISOL facility of the Accelerator Laboratory of the University of Jyväskylä. 62Ga is one of the heavier T z = 0 , 0+ → 0+ β -emitting nuclides used to determine the vector coupling constant of the weak interaction and the Vud quark-mixing matrix element. For part of the experimental studies presented here, the JYFLTRAP facility has been employed to prepare isotopically pure beams of 62Ga . The branching ratio obtained, BR = 99.893(24) %, for the super-allowed branch is in agreement with previous measurements and allows to determine the ft value and the universal Ft value for the super-allowed β -decay of 62Ga.

  8. Beta Decay of 101Sn

    SciTech Connect

    Kavatsyuk, O.; Mazzocchi, C.; Janas, Z.; Banu, A.; Batist, L.; Becker, F.; Blazhev, A.; Bruchle, W.; Doring, J.; Faestermann, T.; Gorska, M.; Grawe, H.; Jungclaus, A.; Karny, M.; Kavatsyuk, M.; Klepper, O.; Kirchner, R.; La Commara, M.; Miernik, K.; Mukha, I.; Plettner, C.; Plochocki, A.; Roeckl, E.; Romoli, M.; Rykaczewski, Krzysztof Piotr; Schadel, M.; Schmidt, K.; Schwengner, R.; Zylicz, J.

    2007-01-01

    The {beta} decay of the very neutron-deficient isotope 101Sn was studied at the GSI on-line mass separator using silicon detectors for recording charged particles and germanium detectors for {gamma}-ray spectroscopy. Based on the {beta}-delayed proton data the production cross-section of 101Sn in the 50Cr + 58Ni fusion-evaporation reaction was determined to be about 60nb. The half-life of 101Sn was measured to be 1.9(3)s. For the first time {beta}-delayed {gamma}-rays of 101Sn were tentatively identified, yielding weak evidence for a cascade of 352 and 1065keV transitions in 101In. The results for the 101Sn decay as well as those from previous work on the 103Sn decay are discussed by comparing them to predictions obtained from shell model calculations employing a new interaction in the 88Sr to 132Sn model space.

  9. Double beta decays and ELEGANT V and VI at Oto Cosmo Observatory

    NASA Astrophysics Data System (ADS)

    Kudomi, N.; Ejiri, H.; Fushimi, K.; Hayashi, K.; Hazama, R.; Kishimoto, T.; Komori, M.; Kume, K.; Kunitomi, G.; Matsuoka, T.; Miyawaki, H.; Nagata, K.; Ohsumi, H.; Okada, K.; Shima, T.; Shiomi, S.; Takahisa, K.; Tanaka, J.; Tasaka, K.; Watanabe, T.

    1998-02-01

    Exclusive measurements of neutrino-less double beta decays(0νββ) of 100Mo were made by means of ELEGANT V at Kamioka Underground Laboratory. Oto Cosmo Observatory has been constructed for underground laboratory for ELEGANT V and VI for the study of 0νββ of 100Mo and 48Ca, search for dark matters and so on.

  10. Neutrinoless double beta decay with Xe-136 in BOREXINO and the BOREXINO Counting Test Facility

    NASA Astrophysics Data System (ADS)

    Caccianiga, B.; Giammarchi, M. G.

    2000-08-01

    This article discusses the methods and sensitivity for a double beta decay experiment based on the Xe-136 candidate for BOREXINO or the BOREXINO Counting Test Facility. Different background assumptions and experimental configurations are studied, assuming a data obtaining period of one year. The related experimental problems are discussed, and summary tables containing the sensitivity estimates for the various configurations are presented.

  11. Current and future searches for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Dolinski, Michelle J.

    2016-09-01

    With the discovery of neutrino oscillations and neutrino mass, it has become a pressing question whether neutrinos have distinct antiparticle states. The most practical experimental approach to answering this question is the search for neutrinoless double beta decay, a version of a rare nuclear process that would violate lepton number conservation. The observation of neutrinoless double beta decay would prove that neutrinos are their own antiparticles. Neutrinoless double beta decay experiments deploy large source masses consisting of a select few (usually enriched) isotopes of interest. Detectors must achieve extremely low levels of radioactive background to detect this rare decay. I will report on recent searches for neutrinoless double beta decay and discuss the technical challenges that the next generation of experiments will overcome.

  12. 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.

  13. Forbidden unique beta-decays and neutrino mass

    NASA Astrophysics Data System (ADS)

    Dvornický, Rastislav; Šimkovic, Fedor

    2013-12-01

    The measurement of the electron spectrum in beta-decays provides a robust direct determination of the values of neutrino masses. The planned rhenium beta-decay experiment, called the "Microcalorimeter Arrays for a Rhenium Experiment" (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which is expected to collect data in a near future. In this contribution we discuss the spectrum of emitted electrons close to the end point in the case of the first unique forbidden beta-decay of 79Se, 107Pd and 187Re. It is found that the p3/2-wave emission dominates over the s1/2-wave. It is shown that the Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed beta-decay of 3H.

  14. 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.

  15. Neutrino-less double beta decays with ELEGANT V

    NASA Astrophysics Data System (ADS)

    Fushimi, Ken-Ichi; Ejiri, Hiroyasu; Kudomi, Nobuyuki; Kume, Kyo; Kuramoto, Hirofumi; Hayashi, Koutaro; Takahisa, Keiji; Yoshida, Sei; Kisimoto, Tadafumi; Matsuoka, Kenji; Ohsumi, Hideaki

    2001-10-01

    Exclusive measurements of neutrinoless double beta decay (0νββ) of ^100Mo were made by means of ELEGANT V. The present status of the double beta decay experiment by means of ELEGANT V is presented. The measurement has been made at Oto Cosmo Observatory in Nara Prefecture, Japan. The stringent limits on the values of , <λ>, <η> and will be reported.

  16. MOON for double-beta decays and neutrino nuclear responses

    NASA Astrophysics Data System (ADS)

    Fushimi, K.; Kameda, Y.; Harada, K.; Nakayama, S.; Ejiri, H.; Shima, T.; Yasuda, K.; Hazama, R.; Imagawa, K.

    2010-01-01

    Thin and wide area inorganic crystal was tested for double beta decay experiment. The thin NaI(Tl) whose dimension of 18cm×18cm×0.5cm was developed. The energy resolution at Q-value of 100Mo was obtained less than 3% in full-width-half-maximum. Although the backscattering of electrons suffers the detection efficiency, the NaI(Tl) has the advantage for double beta decay experiment.

  17. 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.

  18. 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.

  19. Beta-decay rate and beta-delayed neutron emission probability of improved gross theory

    NASA Astrophysics Data System (ADS)

    Koura, Hiroyuki

    2014-09-01

    A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for unmeasured nuclei are adopted from the KTUY nuclear mass formula, which is based on the spherical-basis method. Considering the properties of the integrated Fermi function, we can roughly categorized energy region of excited-state of a daughter nucleus into three regions: a highly-excited energy region, which fully affect a delayed neutron probability, a middle energy region, which is estimated to contribute the decay heat, and a region neighboring the ground-state, which determines the beta-decay rate. Some results will be given in the presentation. A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for

  20. 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

  1. 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

  2. Short-baseline electron neutrino disappearance, tritium beta decay, and neutrinoless double-beta decay

    SciTech Connect

    Giunti, Carlo; Laveder, Marco

    2010-09-01

    We consider the interpretation of the MiniBooNE low-energy anomaly and the gallium radioactive source experiments anomaly in terms of short-baseline electron neutrino disappearance in the framework of 3+1 four-neutrino mixing schemes. The separate fits of MiniBooNE and gallium data are highly compatible, with close best-fit values of the effective oscillation parameters {Delta}m{sup 2} and sin{sup 2}2{theta}. The combined fit gives {Delta}m{sup 2}(greater-or-similar sign)0.1 eV{sup 2} and 0.11(less-or-similar sign)sin{sup 2}2{theta}(less-or-similar sign)0.48 at 2{sigma}. We consider also the data of the Bugey and Chooz reactor antineutrino oscillation experiments and the limits on the effective electron antineutrino mass in {beta} decay obtained in the Mainz and Troitsk tritium experiments. The fit of the data of these experiments limits the value of sin{sup 2}2{theta} below 0.10 at 2{sigma}. Considering the tension between the neutrino MiniBooNE and gallium data and the antineutrino reactor and tritium data as a statistical fluctuation, we perform a combined fit which gives {Delta}m{sup 2}{approx_equal}2 eV and 0.01(less-or-similar sign)sin{sup 2}2{theta}(less-or-similar sign)0.13 at 2{sigma}. Assuming a hierarchy of masses m{sub 1}, m{sub 2}, m{sub 3}<beta} decay and neutrinoless double-{beta} decay are, respectively, between about 0.06 and 0.49 and between about 0.003 and 0.07 eV at 2{sigma}. We also consider the possibility of reconciling the tension between the neutrino MiniBooNE and gallium data and the antineutrino reactor and tritium data with different mixings in the neutrino and antineutrino sectors. We find a 2.6{sigma} indication of a mixing angle asymmetry.

  3. Beta Decay Measurements of Neutron Deficient Cesium Isotopes.

    NASA Astrophysics Data System (ADS)

    Parry, Roger Franklin

    The study of nuclei far from beta stability provides information on nuclear binding energies and nuclear structure. However, as one progresses away from the valley of stability, the associated half-lives and production cross sections decrease with increasing interference from the decays of adjacent nuclei. An experimental solution to these problems was the use of the He-jet fed on-line mass separator, RAMA. This instrument provided a fast and selective technique for the mass separation necessary for the investigation of exotic nuclei. Using this device, a beta decay Q-value study of the neutron deficient cesium isotopes, ('119-123)Cs, was conducted. Beta decay endpoint energy measurements of the neutron deficient cesium isotopes were done using an energy spectrum shape fitting technique. This was a departure from the typical method of endpoint energy analysis, the Fermi-Kurie plot. A discussion of the shape fitting procedure and its improved features are discussed. These beta endpoint measurements have led to total decay energies (Q(,EC)) of the neutron deficient ('119 -123)Cs isotopes. The total decay energies of ('122m)Cs (Q(,EC) = 6.95 (+OR-) 0.25 MeV) and ('119)Cs (Q(,EC) = 6.26 (+OR-) 0.29 MeV) were new measurements. The total decay energies of ('123)Cs (Q(,EC) = 4.05 (+OR-) 0.18 MeV), ('122g)Cs (Q(,EC) = 7.05 (+OR-) 0.18 MeV), ('121)Cs (Q(,EC) = 5.21 (+OR-) 0.22 MeV), and ('120)Cs (Q(,EC) = 7.38 (+OR -) 0.23 MeV) were measurements with significantly improved uncertainties as compared to the literature. Further, a combination of the energy levels derived from previous literature gamma-gamma coincident measurements and the experimental beta-coincident gamma decay energies has supported an improved level scheme for ('121)Xe and the proposal of three new energy levels in ('119)Xe. Comparison of the experimental cesium mass excesses (determined with our Q(,EC) values and known xenon mass excesses) with both the literature and theoretical predicted values showed

  4. 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

  5. Project 8 Phase II: Improved beta decay electrons reconstruction

    NASA Astrophysics Data System (ADS)

    Guigue, Mathieu; Project 8 Collaboration

    2017-01-01

    The Project 8 collaboration aims to measure the absolute neutrino mass scale using a cyclotron radiation emission spectroscopy technique on the beta decays of tritium. The second phase of the project will measure a differential spectrum of tritium beta decays and extract the tritium endpoint value with an eV or sub-eV scale precision. Monoenergetic electrons emitted by gaseous 83mKr atoms can be used to determine the coefficient between the cyclotron frequency and the electron energy and to optimize the instrument configuration for the tritium measurement. We present the progress on the processing of the electron cyclotron radiation signal to reconstruct the beta decay spectrum of krypton and tritium.

  6. Reinvestigation of the beta-decay of 110Mo

    NASA Astrophysics Data System (ADS)

    Wang, J. C.; Dendooven, P.; Hankonen, S.; Huikari, J.; Jokinen, A.; Kolhinen, V. S.; Lhersonneau, G.; Nieminen, A.; Peräjärvi, K.; Rinta-Antila, S.; Äystö, J.

    2004-01-01

    The beta-decay of the neutron-rich nucleus 110Mo, separated by the IGISOL on-line mass separator from other fission products, has been investigated by using beta-gamma and gamma-gamma coincidence techniques. The decay scheme of 110Mo has been revised, including 3 new excited states and 7 new γ transitions in 110Tc. The β -feedings were measured and log {ft} values and B(GT) values were deduced based on a Q_{β}-value from systematics. Three excited 1 + states in 110Tc fed by spin-flip allowed-unhindered beta transitions were identified. The deduced beta-decay strengths are compared with the Gamow-Teller strength distribution obtained from a macroscopic-microscopic calculation. The role of the asymptotic quantum numbers in the context of the allowed beta-decay is discussed.

  7. Searching for Double Beta Decay with the Enriched Xenon Observatory

    SciTech Connect

    Hall, C.; /SLAC

    2007-03-16

    The Enriched Xenon Observatory (EXO) Collaboration is building a series of experiments to search for the neutrinoless double beta decay of {sup 136}Xe. The first experiment, known as EXO-200, will utilize 200 kg of xenon enriched to 80% in the isotope of interest, making it the largest double beta decay experiment to date by one order of magnitude. This experiment is rapidly being constructed, and will begin data taking in 2007. The EXO collaboration is also developing a technique to identify on an event-by-event basis the daughter barium ion of the double beta decay. If successful, this method would eliminate all conventional radioactive backgrounds to the decay, resulting in an ideal experiment. We summarize here the current status of EXO-200 construction and the barium tag R&D program.

  8. Cold fusion: externally induced beta decay of the deuteron?

    SciTech Connect

    Driscoll, R.B.

    1995-04-01

    Plasma frequencies {nu}{sub e} of interstitial electrons in palladium crystals charged with deuterium by electrolysis can reach resonance with the beats of de Broglie group frequencies of deuterons. This frequency can occur during acoustic compressions of lattices due to (1) bubble formation at the Pd cathode, (2) particles from cosmic ray showers, and (3) beta decays of deuterons. Resonance perturbs the orbits of deuterons nucleon constituents with a finite probability of causing dissociation and beta decay -- that is the basic conjecture. The exponential tendency resulting from cause (3) of lattice compression is limited by melting of the lattice, whose integrity is essential for {nu}{sub e}, which drives the decays.

  9. Neutrinoless Double Beta Decay in Light of SNO Salt Data

    SciTech Connect

    Murayama, Hitoshi; Pena-Garay, Carlos

    2003-09-11

    In the SNO data from its salt run, probably the most significant result is the consistency with the previous results without assuming the 8B energy spectrum. In addition, they have excluded the maximal mixing at a very high confidence level. This has an important implication on the double beta decay experiments. For the inverted or degenerate mass spectrum, we find bar_ee bar> 0.013 eV at 95percent CL, and the next generation experiments can discriminate Majorana and Dirac neutrinos if the invertedor degenerate mass spectrum will be confirmed by the improvements in cosmology, tritium data beta decay, or long-baseline oscillation experiments.

  10. Proposed experimental test of Bell's inequality in nuclear beta decay

    SciTech Connect

    Skalsey, M.

    1986-04-15

    A ..beta.. decay experiment is proposed for testing Bell's inequality, related to hidden-variables alternatives to quantum mechanics. The experiment uses Mott scattering for spin polarization analysis of internal conversion electrons. Beta-decay electrons, in cascade with the conversion electrons, are longitudinally polarized due to parity violation in the weak interaction. So simply detecting the ..beta.. electron direction effectively measures the spin. A two-particle spin-spin correlation can thus be investigated and related, within certain assumptions, to Bell's inequality. The example of /sup 203/Hg decay is used for a calculation of expected results. Specific problems related to nuclear structure and experimental inconsistencies are also discussed.

  11. The Majorana Neutrinoless Double-beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Guiseppe, Vincente

    2008-04-01

    Neutrinoless double-beta decay searches play a major role in determining the effective Majorana neutrino mass, the Majorana nature of neutrinos, and a lepton violating process. The Majorana experiment proposes to assemble an array of HPGe detectors to search for neutrinoless double-beta decay in ^76Ge. Initially, Majorana aims to construct a prototype system containing 60 kg of Ge detectors to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of the prototype system will be presented. This talk will also discuss material purity, detector optimization, background rejection, identification of rare backgrounds, and other key technologies to be utilized in the Majorana experiment.

  12. Beta-decay rates: towards a self-consistent approach

    SciTech Connect

    Borzov, I. N.; Goriely, S.; Pearson, J. M.

    1998-02-15

    An approximation to a self-consistent model of the ground state properties and spin-isospin excitations of neutron-rich nuclides is outlined. The structure of the Gamow-Teller strength functions in stable nuclei and short-lived nuclides undergoing high-energy {beta}-decay is discussed. The results of large-scale calculations of the {beta}-decay rates for spherical and slightly deformed nuclides of relevance to the r-process are analysed and compared with the results of existing global calculations.

  13. Neutrinoless double beta decay and chiral SU(3)

    NASA Astrophysics Data System (ADS)

    Cirigliano, V.; Dekens, W.; Graesser, M.; Mereghetti, E.

    2017-06-01

    TeV-scale lepton number violation can affect neutrinoless double beta decay through dimension-9 ΔL = ΔI = 2 operators involving two electrons and four quarks. Since the dominant effects within a nucleus are expected to arise from pion exchange, the π- →π+ ee matrix elements of the dimension-9 operators are a key hadronic input. In this letter we provide estimates for the π- →π+ matrix elements of all Lorentz scalar ΔI = 2 four-quark operators relevant to the study of TeV-scale lepton number violation. The analysis is based on chiral SU (3) symmetry, which relates the π- →π+ matrix elements of the ΔI = 2 operators to the K0 →Kbar0 and K → ππ matrix elements of their ΔS = 2 and ΔS = 1 chiral partners, for which lattice QCD input is available. The inclusion of next-to-leading order chiral loop corrections to all symmetry relations used in the analysis makes our results robust at the 30% level or better, depending on the operator.

  14. Extended operator expansion method for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Hirsch, M.; Kadowaki, O.; Klapdor-Kleingrothaus, H. V.; Muto, K.; Oda, T.

    1995-03-01

    Reliable calculations of nuclear matrix elements are a prerequisite for the determination of the effective neutrino mass and other particle physics parameters from neutrinoless double beta decay. Here, the operator expansion method is improved by including Coulomb, tensor and central interactions simultaneously. Furthermore, the formalism of the OEM is extended to those matrix elements necessary to extract the right-handed parameters < λ > and < η > from 0 νββ decay. OEM includes the dependence of the nuclear matrix elements on the intermediate states implicitly and can therefore be understood as a step beyond the closure approximation. Numerical studies are carried out for the isotope76Ge combining the OEM expressions with ground-state wave functions calculated within a proton-neutron quasiparticle Random Phase Approximation (pn-QRPA) model. The influence and relative importance of central, tensor and Coulomb interactions is investigated. Within the OEM, contributions from the Coulomb force are found to be negligible in 0 νββ decay, while the tensor force leads to a moderate change of the results, of the order of (10 30)%, giving a better agreement between sets of calculations which employ different NN-interactions. Generally, results of the OEM+QRPA calculation are similar to previous calculations of 0 νββ decay matrix elements, indicating that 0 νββ decay is not sensitive to model approximations and might therefore be more accurately calculated than the strongly suppressed 2 νββ decay matrix elements.

  15. Evidence for the emission of a massive neutrino in nuclear beta decay

    SciTech Connect

    Norman, E.B.; Sur, B.; Lesko, K.T.; Larimer, R.M. California Univ., Berkeley, CA . Center for Particle Astrophysics); Hindi, M.M. Tennessee Technological Univ., Cookeville, TN . Dept. of Physics); Ho, T.R.; Luke, P.N.; Hansen, W.L. ); Witort, J.T. . Center

    1990-10-01

    We have studied the {beta}-spectrum of {sup 14}C using a germanium detector containing a crystal with {sup 14}C dissolved in it. We find a feature in the {beta}-spectrum 17 keV below the endpoint which can be explained by the hypothesis that there is a heavy neutrino emitted in the {beta}-decay of {sup 14}C with a mass of 17 {plus minus} 2 keV and an emission probability of 1.40 {plus minus} 0.45%. In addition, we have studied the inner bremsstrahlung spectrum of {sup 55}Fe and also find indications of the emission of a {approximately} 17-keV neutrino. These results are consistent with observations of similar anomalies in the {beta}-decays of {sup 3}H and {sup 35}S. 29 refs., 7 figs.

  16. 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.

  17. Sharpening Low-Energy, Standard-Model Tests via Correlation Coefficients in Neutron {beta} Decay

    SciTech Connect

    Gardner, S.; Zhang, C.

    2001-06-18

    The correlation coefficients a , A , and B in neutron {beta} decay are proportional to the ratio of the axial-vector-to-vector weak coupling constants, g{sub A}/g{sub V} , to leading recoil order. With the advent of the next generation of neutron-decay experiments, the recoil-order corrections to these expressions become experimentally accessible, admitting a plurality of standard model (SM) tests. The measurement of both a and A , e.g., allows one to test the conserved-vector-current (CVC) hypothesis and to search for second-class currents (SCC) independently. The anticipated precision of these measurements suggests that the bounds on CVC violation and SCC from studies of nuclear {beta} decay can be qualitatively bettered.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Searches for massive neutrinos in nuclear beta decay

    SciTech Connect

    Jaros, J.A.

    1992-10-01

    The status of searches for massive neutrinos in nuclear beta decay is reviewed. The claim by an ITEP group that the electron antineutrino mass > 17eV has been disputed by all the subsequent experiments. Current measurements of the tritium beta spectrum limit m[sub [bar [nu

  4. Forbidden unique beta-decays and neutrino mass

    SciTech Connect

    Dvornický, Rastislav; Šimkovic, Fedor

    2013-12-30

    The measurement of the electron spectrum in beta-decays provides a robust direct determination of the values of neutrino masses. The planned rhenium beta-decay experiment, called the “Microcalorimeter Arrays for a Rhenium Experiment” (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which is expected to collect data in a near future. In this contribution we discuss the spectrum of emitted electrons close to the end point in the case of the first unique forbidden beta-decay of {sup 79}Se, {sup 107}Pd and {sup 187}Re. It is found that the p{sub 3/2}-wave emission dominates over the s{sub 1/2}-wave. It is shown that the Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed beta-decay of {sup 3}H.

  5. 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.

  6. The Majorana Demonstrator Neutrinoless Double-beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Guiseppe, V. E.

    2012-03-01

    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 HPGe detectors to search for neutrinoless double-beta decay in ^76Ge. 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-type point contact Ge detectors present advances in background rejection and a significantly lower energy threshold than conventional Ge detectors. 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. Initially, Majorana is constructing a prototype module to demonstrate the potential of a future 1-tonne experiment. The status and potential physics reach of the Majorana Demonstrator module will be presented.

  7. A calorimetric search on double beta decay of 130Te

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Brofferio, C.; Bucci, C.; Capelli, S.; Cremonesi, O.; Fiorini, E.; Giuliani, A.; Nucciotti, A.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Pobes, C.; Previtali, E.; Sisti, M.; Vanzini, M.

    2003-04-01

    We report on the final results of a series of experiments on double beta decay of 130Te carried out with an array of twenty cryogenic detectors. The set-up is made with crystals of TeO2 with a total mass of 6.8 kg, the largest operating one for a cryogenic experiment. Four crystals are made with isotopically enriched materials: two in 128Te and two others in 130Te. The remaining ones are made with natural tellurium, which contains 31.7% and 33.8% 128Te and 130Te, respectively. The array was run under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. By recording the pulses of each detector in anticoincidence with the others a lower limit of 2.1×1023 years has been obtained at the 90% C.L. on the lifetime for neutrinoless double beta decay of 130Te. In terms of effective neutrino mass this leads to the most restrictive limit in direct experiments, after those obtained with Ge diodes. Limits on other lepton violating decays of 130Te and on the neutrinoless double beta decay of 128Te to the ground state of 128Xe are also reported and discussed. An indication is presented for the two neutrino double beta decay of 130Te. Some consequences of the present results in the interpretation of geochemical experiments are discussed.

  8. Time reversal violation in radiative beta decay: experimental plans

    NASA Astrophysics Data System (ADS)

    Behr, J. A.; McNeil, J.; Anholm, M.; Gorelov, A.; Melconian, D.; Ashery, D.

    2017-01-01

    Some explanations for the excess of matter over antimatter in the universe involve sources of time reversal violation (TRV) in addition to the one known in the standard model of particle physics. We plan to search for TRV in a correlation between the momenta of the beta, neutrino, and the radiative gamma sometimes emitted in nuclear beta decay. Correlations involving three (out of four) momenta are sensitive at lowest order to different TRV physics than observables involving spin, such as electric dipole moments and spin-polarized beta decay correlations. Such experiments have been done in radiative kaon decay, but not in systems involving the lightest generation of quarks. An explicit low-energy physics model being tested produces TRV effects in the Fermi beta decay of the neutron, tritium, or some positron-decaying isotopes. We will present plans to measure the TRV asymmetry in radiative beta decay of laser-trapped 38mK at better than 0.01 sensitivity, including suppression of background from positron annihilation. Supported by NSERC, D.O.E., Israel Science Foundation. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

  9. 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.

  10. Cold equation of state in a strong magnetic field - Effects of inverse beta-decay

    NASA Technical Reports Server (NTRS)

    Lai, Dong; Shapiro, Stuart L.

    1991-01-01

    The influence of a high magnetic field (B is greater than 10 exp 12 G) on the degenerate matter equation of state appropriate to a neutron star is studied. The regime dominated by relativistic electrons up to the neutron drip density is highlighted. The equilibrium matter composition and equation of state, allowing for inverse beta-decay. Two different equilibrium models are determined: an ideal neutron-proton-electron (npe) gas and the more realistic model of Baym, Pethick, and Sutherland (1971) consisting of a Coulomb lattice of heavy nuclei embedded in an electron gas. For a sufficiently high field strength, the magnetic field has an appreciable effect, changing the adiabatic index of the matter and the nuclear transition densities. The influence of a strong field on some simple nonequilibrium processes, including beta-decay and inverse beta-decay (electron capture) is also considered. The effects produced by the magnetic field are mainly due to the changes in the transverse electron quantum orbits and the allowed electron phase space induced by the field.

  11. Charge-exchange reactions and nuclear matrix elements for {beta}{beta} decay

    SciTech Connect

    Frekers, D.

    2009-11-09

    Charge-exchange reactions of (n, p) and (p, n) type at intermediate energies are a powerful tool for the study of nuclear matrix element in {beta}{beta} decay. The present paper reviews some of the most recent experiments in this context. Here, the (n, p) type reactions are realized through (d, {sup 2}He), where {sup 2}He refers to two protons in a singlet {sup 1}S{sub 0} state and where both of these are momentum analyzed and detected by the same spectrometer and detector. These reactions have been developed and performed exclusively at KVI, Groningen (NL), using an incident deuteron energy of 183 MeV. Final state resolutions of about 100 keV have routinely been available. On the other hand, the ({sup 3}He, t) reaction is of (p, n) type and was developed at the RCNP facility in Osaka (JP). Measurements with an unprecedented high resolution of 30 keV at incident energies of 420 MeV are now readily possible. Using both reaction types one can extract the Gamow-Teller transition strengths B(GT{sup +}) and B(GT{sup -}), which define the two ''legs'' of the {beta}{beta} decay matrix elements for the 2v{beta}{beta} decay The high resolution available in both reactions allows a detailed insight into the excitations of the intermediate odd-odd nuclei and, as will be shown, some unexpected features are being unveiled.

  12. 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.

  13. 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.

  14. Extra dimensions and neutrinoless double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Góźdź, Marek; Kamiński, Wiesław 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 0ν2β 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. Searches for massive neutrinos in nuclear beta decay

    SciTech Connect

    Jaros, J.A.

    1992-10-01

    The status of searches for massive neutrinos in nuclear beta decay is reviewed. The claim by an ITEP group that the electron antineutrino mass > 17eV has been disputed by all the subsequent experiments. Current measurements of the tritium beta spectrum limit m{sub {bar {nu}}e} < 10 eV. The status of the 17 keV neutrino is reviewed. The strong null results from INS Tokyo and Argonne, and deficiencies in the experiments which reported positive effects, make it unreasonable to ascribe the spectral distortions seen by Simpson, Hime, and others to a 17keV neutrino. Several new ideas on how to search for massive neutrinos in nuclear beta decay are discussed.

  16. First NEXT prototypes for double-beta decay search

    NASA Astrophysics Data System (ADS)

    Yahlali, Nadia; Irastorza, Igor G.; NEXT Collaboration

    2011-02-01

    The NEXT collaboration aims at building a 100 kg high-pressure Xenon gas TPC enriched in 136Xe isotope, to measure its two double-beta decay modes and to explore the degenerate hierarchy of the neutrino mass. The high-pressure Xenon gas offers the possibility to record the event energy with near-intrinsic resolution using electroluminescence, as well as the event track and topology patterns. These are the key features of a robust double-beta decay experiment which are presently being investigated in the first NEXT prototypes, the so-called NEXT0 and NEXT1. In this paper, the prototypes being developed at IFIC and University of Zaragoza are described and preliminary results are outlined.

  17. 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.

  18. New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

    SciTech Connect

    Fairbank, William

    2016-06-08

    This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long-sought-after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x1025 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba

  19. 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.

  20. Branching ratio for sup 10 C superallowed Fermi. beta. decay

    SciTech Connect

    Nagai, Y.; Kunihiro, K.; Toriyama, T.; Harada, S.; Torii, Y.; Yoshida, A. ); Nomura, T.; Tanaka, J. ); Shinozuka, T. )

    1991-01-01

    The branching ratio for {sup 10}C superallowed Fermi {beta} decay has been measured accurately by a newly developed method. The result is 1.473{plus minus}0.007 %. The {ital Ft} value is derived as 3065.4{plus minus}14.7 sec, which is consistent with the {ital Ft} values determined accurately for heavier nuclei and with predictions of conserved vector current hypothesis. The method developed here can be applied to the high precision {beta}-{gamma} spectroscopy.

  1. EXO: A Next Generation Double Beta Decay Experiment

    SciTech Connect

    Hall, C.

    2004-10-28

    The Enriched Xenon Observatory (EXO) is an experiment designed to search for the neutrinoless double beta decay {sup 136}Xe {yields} {sup 136}Ba{sup 2}e{sup -}e{sup -}. To dramatically reduce radioactive backgrounds, the EXO collaboration proposes to tag the final state barium ion event-by-event through its unique atomic spectroscopy. We describe here the current status of the EXO R&D effort.

  2. Beta Decay: A Physics Garden of Earthly Delights

    NASA Astrophysics Data System (ADS)

    Robertson, R. G. Hamish

    2014-03-01

    From the beginning, beta decay has tormented and delighted us with puzzles and enlightenment. A significant part of our present understanding of subatomic physics has emerged from the experimental and theoretical struggle with its mysteries. We reflect on several of the epic victories in this struggle, and look ahead to where ongoing research might lead us in the understanding of fundamental symmetries and neutrinos. Research supported under DOE grant DE-FG02-97ER41020.

  3. 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.

  4. 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.

  5. 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.

  6. SPRT Analysis of Anomalies in Tritium Beta Decay Spectrum

    NASA Astrophysics Data System (ADS)

    Goldman, T.; Stephenson, G. J., Jr.

    1997-10-01

    The experimentally observed deviations from the Kurie plot near the endpoint of Tritium beta decay are opposite to those expected for the case of massive neutrinos. We reexamine(O. Kofoed-Hansen, Phil. Mag. 42), 1448 (1951). the possibility that these deviations are due to new hypoweak interactions. We find that enhancement above the massless neutrino beta spectrum does occur for all cases (scalar, pseudoscalar, tensor or right-handed currents), although it apparently cannot be large enough to explain the data and be consistent with other experimental constraints. Bounds on the strength of these non-standard model interactions are derived.

  7. 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.

  8. beta. -Decay in the Skyrme-Witten representation of QCD

    SciTech Connect

    Snyderman, N.J.

    1991-05-01

    The renormalized coupling strength of the {beta}-decay axial vector current is related to {pi}{plus minus} p cross sections through the Adler-Weisberger sum rule, that follows from chiral symmetry. We attempt to understand the Adler-Weisberger sum rule in the 1/N{sub c} expansion in QCD, and in the Skyrme-Witten model that realizes the 1/N{sub c} expansion in the low energy limit, using it to explicitly calculate both g{sub A} and the {pi}{plus minus} p cross sections. 32 refs.

  9. Limit on electron neutrino mass from observation of the beta decay of molecular tritium

    SciTech Connect

    Wilkerson, J.F.; Bowles, T.J.; Friar, J.L.; Robertson, R.G.H.; Stephenson, G.J. Jr.; Wark, D.L. ); Knapp, D.A. )

    1990-01-01

    We report the most sensitive upper limit set on the mass of the electron antineutrino. The upper limit of 9.4 eV (95% confidence level) was obtained from a study of the shape of the beta decay spectrum of free molecular tritium. Achieving such a level of sensitivity required precise determinations of all processes that modify the shape of the observed spectrum. This result is in clear disagreement with a reported value for the mass of 26(5) eV. 30 refs., 3 figs., 2 tabs.

  10. Beta decay and isomer spectroscopy in the 132Sn region: New results from EURICA

    NASA Astrophysics Data System (ADS)

    Jungclaus, A.; Taprogge, J.; Simpson, G. S.; Gey, G.; Nishimura, S.; Doornenbal, P.; Lorusso, G.; Söderström, P.-A.; Sumikama, T.; Xu, Z.; Baba, H.; Browne, F.; Fukuda, N.; Inabe, N.; Isobe, T.; Jung, H. S.; Kameda, D.; Kim, G. D.; Kim, Y.-K.; Kojouharov, I.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Li, Z.; Sakurai, H.; Schaffner, H.; Suzuki, H.; Takeda, H.; Vajta, Z.; Watanabe, H.; Wu, J.; Yagi, A.; Yoshinaga, K.; Bönig, S.; Daugas, J.-M.; Drouet, F.; Gernhäuser, R.; Ilieva, S.; Kröll, T.; Montaner-Pizá, A.; Moschner, K.; Mücher, D.; Nishibata, H.; Orlandi, R.; Steiger, K.; Wendt, A.

    2014-09-01

    The first EURICA campaign with high intensity Uranium beams took place at RIKEN in November/December 2012. Within this campaign experiment NP1112-RIBF85 was performed dedicated to the study of the isomeric and beta decays of neutron-rich Cd, In, Sn and Sb isotopes towards and beyond the N=82 neutron shell closure. In this contribution we will first provide information about the status of the analysis of the extensive data set obtained in this experiment and close with a short outlook.

  11. The SNO+ Experiment for Neutrinoless Double-Beta Decay

    NASA Astrophysics Data System (ADS)

    Lozza, V.; SNO+ Collaboration

    2016-04-01

    SNO+ is a large scale liquid scintillator based experiment located 2 km underground in a mine near Sudbury, Ontario, Canada. The detector is reusing the Sudbury Neutrino Observatory facility to investigate the Majorana nature of neutrinos through the search for neutrinoless double-beta decay of 130Te. In the double-beta phase about 0.3% natural tellurium will be loaded in the 780 tonnes of liquid scintillator. This corresponds to nearly 800 kg of 130Te. After several years of data taking, it is expected to reach a sensitivity on the effective Majorana neutrino mass below 100 meV. Recent development has suggested that higher loadings, up to few percent, of natural tellurium are possible by which SNO+ could approach, in the near future, the bottom of the inverted hierarchy. Additionally, designed as a general purpose neutrino experiment, SNO+ can measure reactor anti-neutrino oscillations, geo anti-neutrinos in a geologically-interesting location, solar neutrinos and watch supernova neutrinos. A first commissioning phase with the detector filled with water will start at the end of 2014, while the double-beta decay phase is foreseen for the beginning of 2016.

  12. Beta-decay, Bremsstrahlen, and the origin of molecular chirality

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.; Yi, L.

    1984-01-01

    A brief review is presented of the Vester-Ulbricht beta-decay Bremsstrahlen hypothesis for the origin of optical activity, and of subsequent experiments designed to test it. Certain experiments along these lines, begun in 1974 and involving the irradiation of racemic and optically active amino acids in a 61.7 KCi Sr-90-Y-90 Bremsstrahlen source, have now been completed and are described. After 10.89 years of irradiation with a total Bremsstrahlen dose of 2.5 x 10 to the 9th rads, crystalline DL-leucine, norleucine, and norvaline suffered 47.2, 33.6, and 27.4 percent radiolysis, respectively, but showed no evidence whatsoever of asymmetric degradation. Dand L-Leucine underwent about 48 percent radiolysis and showed 2.4-2.9 percent radioracemization. Other samples in solution were too severely degraded to analyze. Probable intrinsic reasons for the failure of the Vester-Ulbricht mechanism to afford asymmetric radiolysis in the present and related experiments involving beta-decay Bremsstrahlen are enumerated.

  13. Search for neutrino-less double beta decay with EXO

    NASA Astrophysics Data System (ADS)

    Gornea, Razvan; EXO Collaboration

    2010-11-01

    Neutrino oscillation experiments have shown that neutrinos have very small but non vanishing masses. These experiments however are not able to determine neither the absolute mass scale of neutrinos nor whether they are two-component Majorana particles, i.e. their own antiparticles. Neutrino-less double beta decay can only occur if the neutrinos are Majorana particles, a preferred scenario in most possible schemes leading to finite masses. Among several viable candidate isotopes, EXO has chosen Xe-136 to search for this decay. Its main advantage is that the final state, i.e. the barium ion, can be tagged using optical spectroscopy. The detection of the double beta decay daughter nucleus can be the key to a background free measurement of such a rare process. An intermediate size detector (EXO-200) of 200 kg enriched xenon (80% Xe-136) is about to take data at the WIPP underground site in New Mexico. A ton-scale experiment is being designed with Ba ion tagging capability. EXO-full will detect, in addition to the two electrons, the coincident appearance of a barium ion. This improved event signature is expected to provide total elimination of the background from radioactive impurities.

  14. Neutrinoless Double Beta Decay and Lepton Flavour Violation in Broken μ - τ Symmetric Neutrino Mass Models

    NASA Astrophysics Data System (ADS)

    Borgohain, Happy; Das, Mrinal Kumar

    2017-09-01

    We have studied neutrinoless double beta decay and charged lepton flavour violation in broken μ - τ symmetric neutrino masses in a generic left-right symmetric model (LRSM). The leading order μ - τ symmetric mass matrix originates from the type I (II) seesaw mechanism, whereas the perturbations to μ - τ symmetry in order for generation of non-zero reactor mixing angle 𝜃 13, as required by latest neutrino oscillation data, originates from the type II (I) seesaw mechanism. In our work, we considered four different realizations of μ - τ symmetry, viz. Tribimaximal Mixing (TBM), Bimaximal Mixing (BM), Hexagonal Mixing (HM) and Golden Ratio Mixing (GRM). We then studied the new physics contributions to neutrinoless double beta decay (NDBD) ignoring the left-right gauge boson mixing and the heavy-light neutrino mixing within the framework of LRSM. We have considered the mass of the gauge bosons and scalars to be around TeV and studied the effects of the new physics contributions on the effective mass and the NDBD half life and compared with the current experimental limit imposed by KamLAND-Zen. We further extended our analysis by correlating the lepton flavour violation of the decay processes, ( μ → 3 e) and ( μ → e γ) with the lightest neutrino mass and atmospheric mixing angle 𝜃 23 respectively.

  15. Neutrinoless Double Beta Decay and Lepton Flavour Violation in Broken μ - τ Symmetric Neutrino Mass Models

    NASA Astrophysics Data System (ADS)

    Borgohain, Happy; Das, Mrinal Kumar

    2017-06-01

    We have studied neutrinoless double beta decay and charged lepton flavour violation in broken μ - τ symmetric neutrino masses in a generic left-right symmetric model (LRSM). The leading order μ - τ symmetric mass matrix originates from the type I (II) seesaw mechanism, whereas the perturbations to μ - τ symmetry in order for generation of non-zero reactor mixing angle 𝜃 13, as required by latest neutrino oscillation data, originates from the type II (I) seesaw mechanism. In our work, we considered four different realizations of μ - τ symmetry, viz. Tribimaximal Mixing (TBM), Bimaximal Mixing (BM), Hexagonal Mixing (HM) and Golden Ratio Mixing (GRM). We then studied the new physics contributions to neutrinoless double beta decay (NDBD) ignoring the left-right gauge boson mixing and the heavy-light neutrino mixing within the framework of LRSM. We have considered the mass of the gauge bosons and scalars to be around TeV and studied the effects of the new physics contributions on the effective mass and the NDBD half life and compared with the current experimental limit imposed by KamLAND-Zen. We further extended our analysis by correlating the lepton flavour violation of the decay processes, (μ → 3e) and (μ → e γ) with the lightest neutrino mass and atmospheric mixing angle 𝜃 23 respectively.

  16. 31Cl beta decay and the 30P31S reaction rate in nova nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Bennett, Michael; Wrede, C.; Brown, B. A.; Liddick, S. N.; Pérez-Loureiro, D.; NSCL e12028 Collaboration

    2016-03-01

    The 30P31S reaction rate is critical for modeling the final isotopic abundances of ONe nova nucleosynthesis, identifying the origin of presolar nova grains, and calibrating proposed nova thermometers. Unfortunately, this rate is essentially experimentally unconstrained because the strengths of key 31S proton capture resonances are not known, due to uncertainties in their spins and parities. Using a 31Cl beam produced at the National Superconducting Cyclotron Laboratory, we have populated several 31S states for study via beta decay and devised a new decay scheme which includes updated beta feedings and gamma branchings as well as multiple states previously unobserved in 31Cl beta decay. Results of this study, including the unambiguous identification due to isospin mixing of a new l = 0 , Jπ = 3 /2+ 31S resonance directly in the middle of the Gamow Window, will be presented, and significance to the evaluation of the 30P31S reaction rate will be discussed. Work supported by U.S. Natl. Sci. Foundation (Grants No. PHY-1102511, PHY-1404442, PHY-1419765, and PHY-1431052); U.S. Dept. of Energy, Natl. Nucl. Security Administration (Award No. DE-NA0000979); Nat. Sci. and Eng. Research Council of Canada.

  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. Low energy photon mimic of the tritium beta decay energy spectrum

    NASA Astrophysics Data System (ADS)

    Malabre-O'Sullivan, Neville

    Tritium is a radioactive hydrogen isotope that is typically produced via neutron interaction with heavy water (D2O), producing tritiated water (DTO). As a result of this, tritium accounts for roughly a third of all occupational exposures at a CANDU type nuclear power plant. This identifies a need to study the biological effects associated with tritium (and low energy electrons in general). However, there are complications regarding the dosimetry of tritium, as well as difficulties in handling and using tritium for the purposes of biophysics experiments. To avoid these difficulties, an experiment has been proposed using photons to mimic the beta decay energy spectrum of tritium. This would allow simulation of the radiation properties of tritium, so that a surrogate photon source can be used for biophysics experiments. Through experimental and computational means, this work has explored the use of characteristic x-rays of various materials to modify the output spectrum of an x-ray source, such that it mimics the tritium beta decay spectrum. Additionally, the resultant primary electron spectrum generated in water from an x-ray source was simulated. The results from this research have indicated that the use of characteristic x-rays is not a viable method for simulating a tritium source. Also, the primary electron spectrum generated in water shows some promise for simulating tritium exposure, however further work must be done to investigate the slowing down electron spectrum. Keywords: Tritium, MCNP, low energy electrons, biophysics, characteristic x-rays.

  19. 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.

  20. 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),

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

    NASA Astrophysics Data System (ADS)

    Álvarez, V.; Bandac, I.; Bettini, A.; Borges, F. I. G. M.; Cárcel, S.; Castel, J.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Dias, T. H. V. T.; Díaz, J.; Egorov, M.; Esteve, R.; Evtoukhovitch, P.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Gil, A.; Goldschmidt, A.; Gómez, H.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Iguaz, F. J.; Irastorza, I. G.; Jinete, M. A.; Labarga, L.; Laing, A.; Liubarsky, I.; Lopes, J. A. M.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Miller, T.; Moiseenko, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; da Luz, H. Natal; Navarro, G.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; de Solórzano, A. Ortiz; Palma, R.; Pérez, J.; Pérez Aparicio, J. L.; Renner, J.; Ripoll, L.; Rodríguez, A.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Segui, L.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Tomás, A.; Torrent, J.; Tsamalaidze, Z.; Vázquez, D.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2013-08-01

    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 136Xe. 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.

  2. Neutrino Mass from Beta Decay of the Free Neutron

    NASA Astrophysics Data System (ADS)

    Tegen, R.; Miller, H. G.

    We calculate the beta decay rate of the free neutron including effects due to (i) a neutrino mass around 1 eV, (ii) deviations from the leptonic V-A structure, (iii) nucleon form factors F1,2V (q2), GA(q2), and (iv) W- propagation. At the end-point energies linear neutrino mass effects in n -> p + e- + ¯ {ν }e are almost exclusively kinematical. If the neutrino spectrum is (almost) degenerate, neutrino oscillations cannot uniquely determine the mass of the neutrino, and direct mass determinations become necessary. The traditional Kurie plot and a partially integrated decay rate are found to be sensitive to a neutrino mass between 1 eV and 3 eV.

  3. Beta decay and the origins of biological chirality - Experimental results

    NASA Technical Reports Server (NTRS)

    Gidley, D. W.; Rich, A.; Van House, J.; Zitzewitz, P. W.

    1982-01-01

    Preliminary experimental results are presented of an investigation of the possible role of preferential radiolysis by electrons emitted in the beta decay of radionuclides, a parity-nonconserving process, in the universal causation of the optical activity of biological compounds. Experiments were designed to measure the asymmetry in the production of triplet positronium upon the bombardment of an amino acid powder target by a collimated beam of positrons as positron helicity or target chirality is reversed. No asymmetry down to a level of 0.0007 is found in experiments on the D and L forms of cystine and tryptophan, indicating an asymmetry in positronium formation cross section of less than 0.01, while an asymmetry of 0.0031 is found for leucine, corresponding to a formation cross section asymmetry of about 0.04

  4. Measurement of Vud with 0+→0+ nuclear beta decays

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.; Towner, I. S.

    2013-10-01

    Results from superallowed 0+→0+ nuclear beta decays today provide the best value for Vud, with an uncertainty of ±0.02%. Some 150 independent measurements of 13 separate superallowed transitions covering a wide range of parent nuclei from 10C to 74Rb constitute a very robust data set. Excellent consistency among the average results for all 13 transitions - an expected consequence of the conservation of vector current (CVC) - also confirms the validity of the small transition-dependent theoretical corrections that have been applied to account for isospin-symmetry breaking. With CVC consistency established, the value of the vector coupling constant, GV, has been extracted from the data and used to determine |Vud| = 0.97425 (22).

  5. 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.

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

    SciTech Connect

    Gironi, L. Biassoni, M.; Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Ferri, E.; Gotti, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sala, E.; Sisti, M.; Terranova, F.; Zanotti, L.; Alduino, C.; and others

    2015-10-28

    The CUORE-0 experiment, a 52 bolometer array searching for neutrinoless double beta decay from {sup 130}Te, 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 {sup 130}Te) 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 (T{sub 1/2} > 4.0 × 10{sup 24} 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.

  7. Development of Micromegas for neutrinoless double beta decay searches

    NASA Astrophysics Data System (ADS)

    Tomás, A.; Carmona, J. M.; Cebrián, S.; Dafni, T.; Ferrer-Ribas, E.; Galán, J.; Giomataris, I.; Gómez, H.; Gorodetzky, P.; Iguaz, F. J.; Irastorza, I. G.; Jeanneau, F.; Luzón, G.; Morales, J.; Papaevangelou, T.; Rodríguez, A.; Ruz, J.; Salin, P.; Seguí, L.; Villar, J. A.

    2009-11-01

    The present paper is a summary of experimental tests performed with microbulk Micromegas for application in a neutrinoless double beta decay experiment based in a xenon TPC. No critical limitation related with high pressure has been detected for Micromegas, which has been tested up to 10 bar. No significant differences have been found between low energy X-rays and high energy alpha tracks regarding ionization yield and electronic transparency of Micromegas mesh. Using 5.5 MeV alphas in argon-isobutane mixtures, values as low as 1.8% FWHM have been obtained, with possible evidence that better resolutions are achievable. These results seems independent of pressure (probed up to 4.5 bar) or gas mixture (microbulks have run in xenon without quencher). The imperative necessity of high quality gas led to start on a new TPC and MPGD dedicated lab at Zaragoza.

  8. 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.

  9. The neutrinoless double beta decay from a modern perspective

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.

    2002-04-01

    Neutrinoless double beta decay is a very important process both from the particle and nuclear physics point of view. From the elementary particle point of view it pops up in almost every model, giving rise, among others, to the following mechanisms: (a) The traditional contributions like the light neutrino mass mechanism as well as the jL- jR leptonic interference ( λ and η terms). (b) The exotic R-parity violating supersymmetric (SUSY) contributions. In this scheme, the currents are only left handed and the intermediate particles normally are very heavy. There exists, however, the possibility of light intermediate neutrinos arising from the combination of V-A and P-S currents at the quark level. This leads to the same structure as the above λ term. Similar considerations apply to its sister lepton and muon number violating muon to positron conversion in the presence of nuclei. Anyway, regardless of the dominant mechanism, the observation of neutrinoless double betas decay, which is the most important of the two from an experimental point of view, will severely constrain the existing models and will signal that the neutrinos are massive Majorana particles. From the nuclear physics point of view it is challenging, because: (1) The nuclei, which can undergo double beta decay, have a complicated nuclear structure. (2) The energetically allowed transitions are suppressed (exhaust a small part of the entire strength). (3) Since in some mechanisms the intermediate particles are very heavy, one must cope with the short distance behavior of the transition operators. Thus novel effects, like the double beta decay of pions in flight between nucleons, have to be considered. In SUSY models this mechanism is more important than the standard two nucleon mechanism. (4) The intermediate momenta involved are quite high (about 100 MeV/c ). Thus, one has to take into account possible momentum-dependent terms of the nucleon current, like the modification of the axial current due to

  10. On improvements of Double Beta Decay using FQTDA Model

    NASA Astrophysics Data System (ADS)

    de Oliveira, L.; Samana, A. R.; Krmpotic, F.; Mariano, A. E.; Barbero, C. A.

    2015-07-01

    The Quasiparticle Tamm-Dancoff Approximation (QTDA) is applied to describe the nuclear double beta decay with two neutrinos. Several serious inconveniences found in the Quasiparticle Random Phase Approximation (QRPA) are not present in the QTDA, as such as the ambiguity in treating the intermediary states, and further approximations necessary for evaluation of the nuclear matrix elements (NMEs) or, the extreme sensitivity of NME with the ratio between the pn and pp + nn pairings. Some years ago, the decay 48Ca → 48Ti was discussed within the particle-hole limit of QTDA. We found some mismatch in the numerical calculations when the full QTDA was being implemented, and a new performance in the particle-hole limit of QTDA is required to guarantee the fidelity of the approximation.

  11. Standard Model and Beyond with Neutron Beta Decay Experiments

    NASA Astrophysics Data System (ADS)

    Liu, Jianglai

    2010-11-01

    The underlying charge-current weak interaction of the neutron beta decay connects together the Fermi constant GF, CKM matrix element Vud, the nucleon axial weak coupling constant gA, and the free neutron life time τn. Consequently, the combination of direct measurements of these provides stringent constraints to the Standard Model. At present, GF and Vud have been measured to a precision of 5 ppm and 225 ppm, respectively, whereas the data in gA and τn are less precise, and both exhibit significant inconsistency among measurements. With polarized neutrons, gA can be determined by measuring the angular correlation of the decay electrons with the neutron spin (so-called β-asymmetry). In the past, β-asymmetry have been measured in the cold neutron beam experiments, yielding a range of results much wider than the reported uncertainties. A new β-asymmetry measurement, UCNA (Ultracold Neutron Asymmetry), has been developed using the solid deuterium pulse spallation ultracold neutron (UCN) source at the Los Alamos Neutron Science Center, where UCN are transported in a guide system, fully polarized, then loaded into a decay trap within a solenoidal beta spectrometer. Utilizing UCN give this experiment very different systematics compared to cold neutron experiments. In this talk, I will give a brief review of the neutron beta decay measurements on the angular correlations as well as the life time. The main focus of this talk will be on the UCNA experiment. I will discuss the experimental techniques, and present the new results from the data in 2008 and 2009. The implication of the new results, combined with the world data on β-asymmetry, Vud, and τn, will also be discussed.

  12. 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.

  13. 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.

  14. The empirical connection between (p,n) cross sections and beta decay transition strengths

    SciTech Connect

    Taddeucci, T.N.

    1988-01-01

    A proportionality is assumed to exist between 0/degree/ (p,n) cross sections and the corresponding beta decay transition strengths. The validity of this assumption is tested by comparison of measured (p,n) cross sections and analogous beta decay strengths. Distorted waves impulse approximation calculations also provide useful estimates of the accuracy of the proportionality relationship. 14 refs., 10 figs.

  15. Search for neutrino-less double beta decay of 48Ca by CaF 2 scintillator

    NASA Astrophysics Data System (ADS)

    Ogawa, I.; Hazama, R.; Miyawaki, H.; Shiomi, S.; Suzuki, N.; Ishikawa, Y.; Kunitomi, G.; Tanaka, Y.; Itamura, M.; Matsuoka, K.; Ajimura, S.; Kishimoto, T.; Ejiri, H.; Kudomi, N.; Kume, K.; Ohsumi, H.; Fushimi, K.

    2004-01-01

    A CaF 2 scintillation detector system (ELEGANT VI) has been operating at Oto Cosmo Observatory to study double beta decays of 48Ca. No events were observed around the Q-value energy region after the analysis of 4.23 kg yr data. To derive the lower limit for the half-life of the neutrino-less double beta decay of 48Ca, the expected number of background events in that energy region was estimated by a Monte Carlo simulation using the measured activities of 214Bi and 220Rn inside CaF 2 crystals. A new lower limit is obtained to be 1.4×10 22 yr at the 90% C.L. An experimental sensitivity is 5.9×10 21 yr at the 90% C.L.

  16. High efficiency beta-decay spectroscopy using a planar germanium double-sided strip detector

    NASA Astrophysics Data System (ADS)

    Larson, N.; Liddick, S. N.; Bennett, M.; Bowe, A.; Chemey, A.; Prokop, C.; Simon, A.; Spyrou, A.; Suchyta, S.; Quinn, S. J.; Tabor, S. L.; Tai, P. L.; Tripathi, Vandana; VonMoss, J. M.

    2013-11-01

    Beta-decay spectroscopy experiments are limited by the detection efficiency of ions and electrons in the experimental setup. While there is a variety of different experimental setups in use for beta-decay spectroscopy, one popular choice is silicon double-sided strip detectors (DSSD). The higher Z of Ge and greater availability of thicker detectors as compared to Si potentially offer dramatic increases in the detection efficiency for beta-decay electrons. In this work, a planar GeDSSD has been commissioned for use in beta-decay spectroscopy experiments at the National Superconducting Cyclotron Laboratory (NSCL). The implantation response of the detector and its beta-decay detection efficiency is discussed.

  17. High-precision {beta} decay half-life measurements of proton-rich nuclei for testing the CVC hypothesis

    SciTech Connect

    Kurtukian-Nieto, T. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan , Universite Bordeaux 1, CNRS Collaboration: NEX Group of CENBG

    2011-11-30

    The experimental study of super-allowed nuclear {beta} decays serves as a sensitive probe of the conservation of the weak vector current (CVC) and allows tight limits to be set on the presence of scalar or right-handed currents. Once CVC is verified, it is possible to determine the V{sub ud} element of the CKM quark-mixing matrix. Similarly, the study of nuclear mirror {beta} decays allows to arrive at the same final quantity V{sub ud}. Whereas dedicated studies of 0{sup +}{yields}0{sup +} decays are performed for several decades now, the potential of mirror transitions was only rediscovered recently. Therefore, it can be expected that important progress is possible with high-precision studies of different mirror {beta} decays. In the present piece of work the half-life measurements performed by the CENBG group of the proton-rich nuclei {sup 42}Ti, {sup 38-39}Ca, {sup 30-31}S and {sup 29}P are summarised.

  18. Measurement of the two-neutrino double-beta decay half-life of ^{130}Te with the CUORE-0 experiment

    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.; 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.; D'Addabbo, A.; Dafinei, I.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Feintzeig, J.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; 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.; Leder, A.; Ligi, C.; 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.; Napolitano, T.; 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.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; 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.

    2017-01-01

    We report on the measurement of the two-neutrino double-beta decay half-life of ^{130}Te with the CUORE-0 detector. From an exposure of 33.4 kg year of TeO_2, the half-life is determined to be T_{1/2}^{2ν } = [8.2 ± 0.2 (stat.) ± 0.6 (syst.)] × 10^{20} year. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the ^{130}Te neutrinoless double-beta decay region of interest.

  19. Measurement of the two-neutrino double-beta decay half-life of $$^{130}$$Te with the CUORE-0 experiment

    DOE PAGES

    Alduino, C.; Alfonso, K.; Artusa, D. R.; ...

    2017-01-06

    Here, we report on the measurement of the two-neutrino double-beta decay half-life of 130Te with the CUORE-0 detector. From an exposure of 33.4 kg year of TeO2, the half-life is determined to be T2ν1/2 = [8.2 ± 0.2 (stat.) ± 0.6 (syst.)] × 1020 year. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the 130Te neutrinoless double-beta decay region of interest.

  20. Beta-decay half-lives and beta-delayed neutron emisison probabilities of nuclei in the region A. 110, relevant for the r-process

    SciTech Connect

    Moller, Peter; Pereira, J; Hennrich, S; Aprahamian, A; Arndt, O; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Kessler, R; Kratz, K - L; Lorusso, G; Mantica, P F; Matos, M; Montes, F; Pfeiffer, B; Schatz, F; Schnorrenberger, L; Smith, E; Stolz, A; Quinn, M; Walters, W B; Wohr, A

    2009-01-01

    Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

  1. {beta}-decay half-lives and {beta}-delayed neutron emission probabilities of nuclei in the region A < or approx. 110, relevant for the r process

    SciTech Connect

    Pereira, J.; Galaviz, D.; Matos, M.; Montes, F.; Hennrich, S.; Kessler, R.; Schertz, F.; Aprahamian, A.; Quinn, M.; Woehr, A.; Arndt, O.; Pfeiffer, B.; Becerril, A.; Elliot, T.; Estrade, A.; Lorusso, G.; Schatz, H.; Kratz, K.-L.; Mantica, P. F.; Moeller, P.

    2009-03-15

    Measurements of {beta}-decay properties of A < or approx. 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr, and {sup 111}Mo, along with {beta}-delayed neutron emission probabilities of {sup 104}Y, {sup 109,110}Mo and upper limits for {sup 105}Y, {sup 103-107}Zr, and {sup 108,111}Mo have been measured for the first time. Studies on the basis of the quasi-random-phase approximation are used to analyze the ground-state deformation of these nuclei.

  2. Precise branching-ratio measurement for the superallowed Fermi beta decay of 34Ar at NIRS-HIMAC

    NASA Astrophysics Data System (ADS)

    Kinno, Shumpei; Himac H312 Collaboration

    2014-09-01

    The precise measurement of the ft values for superallowed Fermi beta decays is a valuable tool to explore weak interactions. The resulting ft values can confirm the CVC hypothesis, the unitarity of CKM matrix, and the existence of large isospin-symmetry breaking. Recently, the mirror superallowed Fermi beta decays, 38Ca --> 38mK and 38mK --> 38Ar, have been reported as a sensitive test of the isospin-symmetry breaking. In order to study the mirror superallowed Fermi beta decays in A = 34 systems, the precise measurement for the branching ratios of 34Ar emitter has been performed.The experiment was carried out at NIRS-HIMAC. The secondary beam including 34Ar was produced with the projectile fragmentation of a 500-MeV/u 36Ar beam on a CH2 target. The secondary beam was separated and identified by passing through the secondary beam line. After decreasing the beam energy with an Al degrader of variable thickness, the beam was implanted in the center of a 6-mm thick GSO scintillator surrounded by four clover Ge detectors. The beta and gamma rays were detected by the GSO stopper and the clover Ge detectors, respectively. By analyzing the beta- and gamma-rays energy and time spectra, the branching ratios of 34Ar have been determined.

  3. Dilepton bounds on left-right symmetry at the LHC run II and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Lindner, Manfred; Queiroz, Farinaldo S.; Rodejohann, Werner

    2016-11-01

    In the light of the new 13 TeV dilepton data set with 3.2 fb-1 integrated luminosity from the ATLAS Collaboration, we derive limits on the Z‧ mass in the context of left-right symmetric models and exploit the complementarity with dijet and lljj data, as well as neutrinoless double beta decay. We keep the ratio of the left- and right-handed gauge coupling free in order to take into account different patterns of left-right symmetry breaking. By combining the dielectron and dimuon data we can exclude Z‧ masses below 3 TeV for gR =gL, and for gR ∼ 1 we rule out masses up to ∼ 4 TeV. Those comprise the strongest direct bounds on the Z‧ mass from left-right models up to date. We show that in the usual plane of right-handed neutrino and charged gauge boson mass, dilepton data can probe a region of parameter space inaccessible to neutrinoless double beta decay and lljj studies. Lastly, through the mass relation between WR and Z‧ we present an indirect bound on the lifetime of neutrinoless double beta decay using dilepton data. Our results prove that the often ignored dilepton data in the context of left-right models actually provide important complementary limits.

  4. Search for the Neutrino Less Double Beta Decay

    SciTech Connect

    Efremenko, Yuri

    2016-07-11

    During the past few years our understanding of neutrino properties has reached a new level, with experiments such as Super-K, SNO, KamLAND, and others obtaining exciting results. Major questions such as “Do neutrinos have mass?” and “Do neutrinos oscillate?” now have positive answers. However, an extensive program of neutrino research remains. Undoubtedly, the most important of these is the question pointed out by the National Research Council in its February 2002 report “Connecting Quarks with the Cosmos”, specifically: What are the masses of neutrinos and how have they shaped the evolution of the Universe? The MAJORANA collaboration has proposed to build the world’s most sensitive one-ton scale experiment to search for neutrino less double beta decay to answer this question. In its initial stage, the collaboration is building a prototype MAJORANA DEMONSTRATOR (MJD) experiment consisting of detectors made out of enriched Ge76 with a total sensitive mass of ~30 kg. This will accomplish two goals. First, it will test not yet confirmed claim for observation of neutrino-less double beta decay. Second, it will establish that the selected technology is capable of extension to a one-ton experiment with sufficient sensitivity to measure neutrino mass mββ down to 10 meV. To achieve the last goal, collaboration must demonstrate that a background level of 1 count per year per 4 keV per ton of detector is achievable. The University of Tennessee (UT) neutrino group has made a major commitment to the MJD. P.I. accepted the responsibility for one of the major tasks of the experiment, “Materials and Assay Task” which is crucial to the achievement of low background levels required for the experiment. In addition, the UT group is committed to construct, commission, and operate the MJD active veto system. Those activities were supported by NP-DOE via program funding for “Search for the Neutrino Less Double Beta Decay” at the University

  5. MOON for double beta decays and X-rays from WIMP nuclear interactions

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    2006-07-01

    Neutrino-less double beta decays (0νββ) and direct observation of cold dark matter (DM) are of great interest for studying fundamental properties of neutrinos and weakly interacting massive particles (WIMPs). These are crucial for particle physics and cosmology beyond the standard electro-weak theory. The present seminar in the Erice neutrino school reports briefly (1) the effective neutrino mass studied by 0νββ, (2) the unique features and the present status of MOON (Molybdenum Observatory Of Neutrinos) for high-sensitivity 0νββ studies with 100Mo in the quasi-degenerate and inverted hierarchy regions, and (3) the direct detection of WIMPs by measuring atomic X-rays following inner-shell ionization by WIMPs nuclear interactions. The MOON project is carried out in collaboration with the MOON collaboration, and the X-ray work from WIMPs is done with Ch.C. Moustakidis and J.D. Vergados.

  6. Nuclear responses for double-beta decays by hadron, photon, and neutrino probes and MOON experiment

    NASA Astrophysics Data System (ADS)

    Ejiri, H.

    2006-05-01

    Neutrino-less double-beta decays (0νββ) with the mass sensitivities of the solar and atmospheric ν masses are of great interest for studying the Majorana nature of neutrinos and the absolute mass spectrum as suggested by recent ν oscillation experiments. Here nuclear responses (nuclear matrix elements) for 0νββ are crucial. They are well studied experimentally by using charge-exchange, photo-nuclear and neutrino reactions. MOON(Mo Observatory Of Neutrinos) is a high sensitivity 0νβ β experiment with the mass sensitivity of an order of 30 meV. Experimental studies of the nuclear responses and the present status of MOON are briefly discussed.

  7. 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.

  8. Production and beta decay of rp-process nuclei 96Cd, 98In, and 100Sn.

    PubMed

    Bazin, D; Montes, F; Becerril, A; Lorusso, G; Amthor, A; Baumann, T; Crawford, H; Estrade, A; Gade, A; Ginter, T; Guess, C J; Hausmann, M; Hitt, G W; Mantica, P; Matos, M; Meharchand, R; Minamisono, K; Perdikakis, G; Pereira, J; Pinter, J; Portillo, M; Schatz, H; Smith, K; Stoker, J; Stolz, A; Zegers, R G T

    2008-12-19

    The beta-decay properties of the N=Z nuclei 96Cd, 98In, and 100Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory by fragmenting a 120 MeV/nucleon 112Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10-30. The half-life of 96Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp process, is 1.03_{-0.21};{+0.24} s. The implications of the experimental T_{1/2} value of 96Cd on the abundances predicted by rp process calculations and the origin of A=96 isobars such as 96Ru are explored.

  9. Standard-Model Tests with Superallowed {beta} Decay: Nuclear Data Applied to Fundamental Physics

    SciTech Connect

    Hardy, J.C.

    2005-05-24

    The study of superallowed nuclear {beta} decay currently provides the most precise and convincing confirmation of the conservation of the vector current (CVC) and is a key component of the most demanding available test of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, a basic pillar of the Electroweak Standard Model. Experimentally, the Q-value, half-life, and branching ratio for superallowed transitions must be determined with a precision better than 0.1%. This demands metrological techniques be applied to short-lived ({approx}1 s) activities and that strict standards be employed in surveying the body of world data. The status of these fundamental studies is summarized and recent work described.

  10. Determination of the direction to a source of antineutrinos via inverse beta decay in Double Chooz

    NASA Astrophysics Data System (ADS)

    Nikitenko, Ya.

    2016-11-01

    To determine the direction to a source of neutrinos (and antineutrinos) is an important problem for the physics of supernovae and of the Earth. The direction to a source of antineutrinos can be estimated through the reaction of inverse beta decay. We show that the reactor neutrino experiment Double Chooz has unique capabilities to study antineutrino signal from point-like sources. Contemporary experimental data on antineutrino directionality is given. A rigorous mathematical approach for neutrino direction studies has been developed. Exact expressions for the precision of the simple mean estimator of neutrinos' direction for normal and exponential distributions for a finite sample and for the limiting case of many events have been obtained.

  11. 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.

  12. 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.

  13. Superallowed fermi beta decay and Coulomb mixing in nuclei

    SciTech Connect

    Hardy, J. C.; Towner, I. S.

    1999-09-02

    Superallowed 0{sup +}{yields}0{sup +} nuclear beta decay provides a direct measure of the weak vector coupling constant, G{sub v}. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of {sup 10}C to that of {sup 54}Co, and demonstrate that the results confirm conservation of the weak vector current (CVC) but differ at the 98% confidence level from the unitarity condition for the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We examine the reliability of the small calculated corrections that have been applied to the data, and conclude that there are no evident defects although the Coulomb correction, {delta}{sub C}, depends sensitively on nuclear structure and thus needs to be constrained independently. The potential importance of a result in disagreement with unitarity, clearly indicates the need for further work to confirm or deny the discrepancy. We examine the options and recommend priorities for new experiments and improved calculations. Some of the required experiments depend upon the availability of intense radioactive beams. Others are possible with existing facilities. (c) 1999 American Institute of Physics.

  14. The beta decay asymmetry parameter of /sup 35/Ar

    SciTech Connect

    Garnett, J.D.

    1987-11-01

    The beta decay asymmetry parameter for /sup 35/Ar = /sup 35/Cl + e/sup +/ + nu/sub e/ has been remeasured in order to resolve a long standing puzzle. Previous asymmetry measurements, when combined with the comparative half-life, yield a value for the vector coupling constant, G/sub v/, that is in serious disagreement with the accepted value. We produced polarized /sup 35/Ar by a (p,n) reaction on /sup 35/Cl using the polarized proton beam provided by Lawrence Berkeley Laboratory's 88-Inch Cyclotron. The polarization of the /sup 35/Ar was determined by measuring the asymmetry of the positrons produced in /sup 35/Ar decay to the first excited state in /sup 35/Cl (branching ratio = 1.3%) in coincidence with a 1219.4 keV gamma ray. Our result, A/sub 0/ = 0.49 +- 0.10, combined with the comparative half-life yields a value for G/sub v/ in agreement with the accepted value.

  15. QCD-improved limits from neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Arbeláez, C.; González, M.; Kovalenko, S. G.; Hirsch, M.

    2017-07-01

    We analyze the impact of QCD corrections on limits derived from neutrinoless double beta decay (0 ν β β ). As demonstrated previously, the effect of the color mismatch arising from loops with gluons linking the quarks from different color-singlet currents participating in the effective operators has a dramatic impact on the predictions for some particular Wilson coefficients. Here, we consider all possible contributions from heavy particle exchange, i.e. the so-called short-range mechanism of 0 ν β β decay. All high-scale models (HSM) in this class match at some scale around a ˜ few TeV with the corresponding effective theory, containing a certain set of effective dimension-9 operators. Many of these HSM receive contributions from more than one of the basic operators and we calculate limits on these models using the latest experimental data. We also show with one nontrivial example, how to derive limits on more complicated models, in which many different Feynman diagrams contribute to 0 ν β β decay, using our general method.

  16. Commissioning and calibrating the CUORE neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Cushman, Jeremy S.; Cuore Collaboration

    2015-04-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double beta decay (0 νββ) of 130 Te. The experiment consists of 988 ultracold TeO2 bolometric crystals, which act as both the source and detector of this decay. We have completed the CUORE detector construction, and commissioning of the CUORE cryostat is ongoing, with the cryostat having reached a stable base temperature below 10 mK. Due to the large number of crystals and extensive shielding around the detector, calibration sources will need to be placed inside the CUORE cryostat during calibration periods to uniformly irradiate the detectors. We have verified that we can deploy room-temperature calibration sources into the cryostat, cool them to this base temperature, and extract them, all with minimal effects on the cryostat. I will present the status of the cryostat commissioning and the commissioning of the CUORE Detector Calibration System, including the results of the first calibration string deployment to 10 mK.

  17. Status of the EXO-200 double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Mackay, Derek

    2008-10-01

    The EXO collaboration is presently constructing and commissioning the world's largest search for neutrinoless double beta decay. The centerpiece of this experiment, known as EXO-200, is 200 kilograms of xenon enriched to 80% in Xenon-136. The xenon is cooled to 170 K, where it liquefies, and is held in a thin copper vessel inside several layers radioactive shielding. Ionizing events in the liquid xenon produce a charge signal which we observe on a segmented anode and a scintillation signal which is collected by array of avalanche photodiodes (APDs). The detector measures the three dimensional event location and the energy of the individual charge deposits, and it can distinguish between multiple-site Compton scattering events and single-site signal candidates. The experiment is located underground at the WIPP facility in Carlsbad, New Mexico, and is currently undergoing final commissioning in preparation for physics data taking. We will present in this talk the current status of our preparations and our expected neutrino mass sensitivity.

  18. Neutrinoless Double Beta Decay from a Modern Perspective

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.

    2002-04-01

    Neutrinoless double beta decay is important both from the particle and nuclear physics point of view. From the elementary particle point of view it pops up everywhere , giving rise to the following: The light and heavy neutrino average mass, the right handed λ and η couplings, the SUSY R-parity breaking lepton violating parameter as well as that arising from physics in extra dimensions (branes) etc. Regardless of the dominant mechanism its observation will signal that the neutrinos are massive Majorana particles. From the nuclear physics point of view it is challenging because: 1) The relevant nuclei have complicated nuclear structure. 2) The energetically allowed transitions are suppressed . 3) The intermediate particles in some mechanisms are so heavy that the short distance behavior must be tackled. 4) The momentum dependent terms of the nucleon current cannot be ignored. Taking such effects into account the nuclear matrix elements for A = 76, 82, 96, 100, 116, 128, 130, 136 and 150 have become reliable. From the presently available experimental limits on the half-lives, new limits on the relevant lepton violating parameters have been extracted imposing stringent constraints on the fashionable particle models.

  19. 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.

  20. A Novel Approach to β-delayed Neutron Spectroscopy Using the Beta-decay Paul Trap

    NASA Astrophysics Data System (ADS)

    Scielzo, N. D.; Yee, R. M.; Bertone, P. F.; Buchinger, F.; Caldwell, S. A.; Clark, J. A.; Czeszumska, A.; Deibel, C. M.; Greene, J. P.; Gulick, S.; Lascar, D.; Levand, A. F.; Li, G.; Norman, E. B.; Padgett, S.; Pedretti, M.; Perez Galvan, A.; Savard, G.; Segel, R. E.; Sharma, K. S.; Sternberg, M. G.; Van Schelt, J.; Zabransky, B. J.

    2014-06-01

    A new approach to β-delayed neutron spectroscopy has been demonstrated that circumvents the many limitations associated with neutron detection by instead inferring the decay branching ratios and energy spectra of the emitted neutrons by studying the nuclear recoil. Using the Beta-decay Paul Trap, fission-product ions were trapped and confined to within a 1-mm3 volume under vacuum using only electric fields. Results from recent measurements of 137I+ and plans for development of a dedicated ion trap for future experiments using the intense fission fragment beams from the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory are summarized. The improved nuclear data that can be collected is needed in many fields of basic and applied science such as nuclear energy, nuclear astrophysics, and stockpile stewardship.

  1. A Novel Approach to β-delayed Neutron Spectroscopy Using the Beta-decay Paul Trap

    SciTech Connect

    Scielzo, N.D.; Yee, R.M.; Bertone, P.F.; Buchinger, F.; Caldwell, S.A.; Clark, J.A.; Czeszumska, A.; Deibel, C.M.; Greene, J.P.; Gulick, S.; Lascar, D.; Levand, A.F.; and others

    2014-06-15

    A new approach to β-delayed neutron spectroscopy has been demonstrated that circumvents the many limitations associated with neutron detection by instead inferring the decay branching ratios and energy spectra of the emitted neutrons by studying the nuclear recoil. Using the Beta-decay Paul Trap, fission-product ions were trapped and confined to within a 1-mm{sup 3} volume under vacuum using only electric fields. Results from recent measurements of {sup 137}I{sup +} and plans for development of a dedicated ion trap for future experiments using the intense fission fragment beams from the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory are summarized. The improved nuclear data that can be collected is needed in many fields of basic and applied science such as nuclear energy, nuclear astrophysics, and stockpile stewardship.

  2. 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.

  3. 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.

  4. 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.

  5. Superconducting solenoid magnet of the DCBA-T3 experiment searching for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Kawai, M.; Kondou, Y.; Makida, Y.; Haruyama, T.; Ishihara, N.; Kobayashi, Y.; Iwai, G.; Iwase, H.; Ohama, T.; Takahashi, K.; Yamada, Y.; Kato, Y.; Tanaka, K.; Tonooka, M.; Kitamura, S.; Ishikawa, T.; Igarashi, H.; Kakuno, H.; Sumiyoshi, T.; Tajima, T.; Ishizuka, T.; Ito, R.; Tamura, N.

    2014-03-01

    The experiment of neutrinoless double beta decay (0ν β β) is the only realistic method for investigating the Majorana nature and the absolute mass scale of neutrinos. An R&D project called Drift Chamber Beta-ray Analyzer (DCBA) has been developing a magnetic tracking detector for 0ν β β experiments at KEK. A superconducting solenoid magnet (SCSM) has been constructed to produce a uniform magnetic field for the prototype test facility called DCBA-T3. The results of SCSM test runs are described, as well as its design studies. Since the SCSM is a prototype magnet for a future detector temporarily called Magnetic Tracking Detector (MTD), it is essential to understand its long-term operation. The experience of about two years of operation is also described.

  6. Non-collapsing renormalized QRPA with proton-neutron pairing for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Simkovic, F.; Schwieger, J.; Veselský, M.; Pantis, G.; Faessler, Amand

    1997-02-01

    Using the renormalized quasiparticle random phase approximation (RQRPA), we calculate the light neutrino mass mediated mode of neutrinoless double beta decay (0νββ-decay) of 76Ge, 100Mo, 128Te and 130Te. Our results indicate that the simple quasiboson approximation is not good enough to study the 0νββ-decay, because its solutions collapse for physical values of gpp. We find that extension of the Hilbert space and inclusion of the Pauli principle in the QRPA with proton-neutron pairing, allows us to extend our calculations beyond the point of collapse, for physical values of the nuclear force strength. As a consequence one might be able to extract more accurate values on the effective neutrino mass by using the best available experimental limits on the half-life of 0νββ-decay.

  7. Present and future of double-beta decay searches with bolometric detectors

    NASA Astrophysics Data System (ADS)

    Cardani, L.

    2016-01-01

    Thanks to the excellent energy resolution, high efficiency and versatility, bolometric detectors are primed for the search of neutrinoless double-beta decay (0 ν DBD). The most advanced bolometric experiment, CUORE, is studying the 0 ν DBD of 130Te using a 741kg array of TeO2 crystals. CUORE points to a 90% CL sensitivity on the half-life of 0 ν DBD of 9.5×1025 yr in 5yr, corresponding to an upper limit on the neutrino Majorana mass of 50-130meV. This sensitivity will allow to touch, but not to explore, the region corresponding to the inverted hierarchy mass scenario. In this document I present the status of CUORE and the possible upgrades of the bolometric technology in view of a next generation experiment.

  8. Large Area APDs in the EXO-200 neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Neilson, Russell

    2009-10-01

    EXO (Enriched Xenon Observatory) is a program aimed at building a ton-class neutrinoless double beta decay detector using xenon enriched to 80% in the isotope 136 as the source and detection medium. The first EXO experiment, known as EXO-200, is currently being commissioned in its underground location at the WIPP facility in Carlsbad, New Mexico. The centerpiece of EXO-200 is a liquid xenon TPC containing 200 kg of enriched xenon with simultaneous readout of ionization and scintallation. Scintallation photons are detected by 468 large area avalanche photodiodes (LAAPDs). This talk will briefly summarize the current status of EXO-200 and describe our study and characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.

  9. A search for neutrinoless double beta decay of [sup 130]Te with a low temperature calorimeter

    SciTech Connect

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

    1992-02-05

    Possible impacts of the bolometric technique on Neutrinoless Double Beta Decay (0[nu]-DVD) search are discussed. In this approach, the performances of two TeO[sub 2] low temperature calorimeters with masses of 73 g and 340 g are reported: the FWHM resolutions are respectively 6 keV and 20 keV at 2614 keV. The operation of these detectors in a low background environment in the Gran Sasso underground laboratory has allowed to set a limit on the half-life of [sup 130]Te 2[nu]-DBD of about 2.5[times]10[sup 21] and to study the residual radioactive background components.

  10. Spin dipole nuclear matrix elements for double beta decay nuclei by charge-exchange reactions

    NASA Astrophysics Data System (ADS)

    Ejiri, H.; Frekers, D.

    2016-11-01

    Spin dipole (SD) strengths for double beta-decay (DBD) nuclei were studied experimentally for the first time by using measured cross sections of (3He, t) charge-exchange reactions (CERs). Then SD nuclear matrix elements (NMEs) {M}α ({{SD}}) for low-lying 2- states were derived from the experimental SD strengths by referring to the experimental α = GT (Gamow-Teller) and α = F (Fermi) strengths. They are consistent with the empirical NMEs M({{SD}}) based on the quasi-particle model with the empirical effective SD coupling constant. The CERs are used to evaluate the SD NME, which is associated with one of the major components of the neutrino-less DBD NME.

  11. 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.

  12. 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.

  13. Fundamental processes in the interacting boson model: 0{nu}{beta}{beta} decay

    SciTech Connect

    Iachello, F.; Barea, J.

    2011-05-06

    A program to calculate nuclear matrix elements for fundamental processes in the interacting boson model has been initiated. Results for the nuclear matrix elements in neutrinoless double beta decay 0{nu}{beta}{beta} are presented.

  14. Internal Energy Loss of the Electrons Ejected in Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Drukarev, E. G.; Amusia, M. Ya.; Chernysheva, L. V.

    2017-01-01

    The excitations of the electron shell in neutrinoless double beta decay shifts the limiting energy available for ejected electrons. We present the general equations for this shift and make computations for the decays of two nuclei—germanium and xenon.

  15. Absolute mass of neutrinos and the first unique forbidden {beta} decay of {sup 187}Re

    SciTech Connect

    Dvornicky, Rastislav; Simkovic, Fedor; Muto, Kazuo; Faessler, Amand

    2011-04-15

    The planned rhenium {beta}-decay experiment, called the ''Microcalorimeter Arrays for a Rhenium Experiment'' (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which will take commissioning data in 2011 and will proceed for 5 years. We present the energy distribution of emitted electrons for the first unique forbidden {beta} decay of {sup 187}Re. It is found that the p-wave emission of electron dominates over the s wave. By assuming mixing of three neutrinos, the Kurie function for the rhenium {beta} decay is derived. It is shown that the Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed {beta} decay of {sup 3}H.

  16. Beta-decay spectroscopy relevant to the r-process nucleosynthesis

    SciTech Connect

    Nishimura, Shunji; Collaboration: RIBF Decay Collaboration

    2012-11-12

    A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

  17. Superallowed nuclear beta decay: Precision measurements for basic physics

    SciTech Connect

    Hardy, J. C.

    2012-11-20

    For 60 years, superallowed 0{sup +}{yields}0{sup +} nuclear beta decay has been used to probe the weak interaction, currently verifying the conservation of the vector current (CVC) to high precision ({+-}0.01%) and anchoring the most demanding available test of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix ({+-}0.06%), a fundamental pillar of the electroweak standard model. Each superallowed transition is characterized by its ft-value, a result obtained from three measured quantities: the total decay energy of the transition, its branching ratio, and the half-life of the parent state. Today's data set is composed of some 150 independent measurements of 13 separate superallowed transitions covering a wide range of parent nuclei from {sup 10}C to {sup 74}Rb. Excellent consistency among the average results for all 13 transitions - a prediction of CVC - also confirms the validity of the small transition-dependent theoretical corrections that have been applied to account for isospin symmetry breaking. With CVC consistency established, the value of the vector coupling constant, G{sub V}, has been extracted from the data and used to determine the top left element of the CKM matrix, V{sub ud}. With this result the top-row unitarity test of the CKM matrix yields the value 0.99995(61), a result that sets a tight limit on possible new physics beyond the standard model. To have any impact on these fundamental weak-interaction tests, any measurement must be made with a precision of 0.1% or better - a substantial experimental challenge well beyond the requirements of most nuclear physics measurements. I overview the current state of the field and outline some of the requirements that need to be met by experimentalists if they aim to make measurements with this high level of precision.

  18. Testing CVC and CKM Unitarity via superallowed nuclear beta decay

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.; Towner, I. S.; Park, H. I.; Iacob, V. E.; Chen, L.; Horvat, V.; Nica, N.; Bencomo, M.

    2015-05-01

    Currently, the most restrictive test of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is anchored by nuclear beta decay. Precise measurements of the ft-values for superallowed beta transitions between analog 0+ states are used to determine GV, the vector coupling constant; this, in turn, yields Vud, the up-down quark-mixing element of the CKM matrix. The determination of a transition's ft-value requires the measurement of three quantities: its Q value, branching ratio and parent half-life. To achieve 0.1% precision on the final result, each of these quantities must be measured to substantially better precision, for which special techniques have had to be developed. A new survey and analysis of world data reveals that there are now fourteen such transitions with ft-values known to ˜ 0.1% precision or better, and that they span a wide range of nuclear masses, from 10C, the lightest parent, to 74Rb, the heaviest. Of particular interest is the recent completion of the first mirror pair of 0+ → 0+ transitions, 38Ca → 38mK and 38mK → 38Ar, which provides a valuable constraint on the calculated isospin-symmetry-breaking corrections needed to derive GV from the experimental data. As anticipated by the Conserved Vector Current hypothesis, CVC, all fourteen transitions yield consistent values for GV. The value of Vud derived from their average makes it by far the most precisely known element of the CKM matrix, which, when combined with the other top-row elements, Vus and Vub, leads to the most demanding test available of the unitarity of that matrix. Since CKM unitarity is a key pillar of the Electroweak Standard Model, this test is of fundamental significance.

  19. Superallowed nuclear beta decay: Precision measurements for basic physics

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.

    2012-11-01

    For 60 years, superallowed 0+→0+ nuclear beta decay has been used to probe the weak interaction, currently verifying the conservation of the vector current (CVC) to high precision (±0.01%) and anchoring the most demanding available test of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix (±0.06%), a fundamental pillar of the electroweak standard model. Each superallowed transition is characterized by its ft-value, a result obtained from three measured quantities: the total decay energy of the transition, its branching ratio, and the half-life of the parent state. Today's data set is composed of some 150 independent measurements of 13 separate superallowed transitions covering a wide range of parent nuclei from 10C to 74Rb. Excellent consistency among the average results for all 13 transitions - a prediction of CVC - also confirms the validity of the small transition-dependent theoretical corrections that have been applied to account for isospin symmetry breaking. With CVC consistency established, the value of the vector coupling constant, GV, has been extracted from the data and used to determine the top left element of the CKM matrix, Vud. With this result the top-row unitarity test of the CKM matrix yields the value 0.99995(61), a result that sets a tight limit on possible new physics beyond the standard model. To have any impact on these fundamental weak-interaction tests, any measurement must be made with a precision of 0.1% or better - a substantial experimental challenge well beyond the requirements of most nuclear physics measurements. I overview the current state of the field and outline some of the requirements that need to be met by experimentalists if they aim to make measurements with this high level of precision.

  20. Development of detector technologies for neutron beta decay measurements

    NASA Astrophysics Data System (ADS)

    Choi, Jin Ha; Cude-Woods, Chris; Young, Albert; Los Alamos UCN Collaboration Collaboration

    2016-09-01

    In the past year we have developed two detector technologies for neutron beta decay measurements. The first is designed specifically to detect the recoil proton from neutron decay. In particular, the PERKEO III experiments planned for the Institut Laue Langevin require detectors with active area greater than about 600 cm2 area to achieve the targeted statistical sensitivity. We have developed an implementation of transmission foil detectors utilizing free standing foils of roughly 100 nm thickness and 700 cm2 area, coated with LiF converting crystal. These foils are placed in an accelerating electric field geometry to first accelerate the protons to 30 kV and then convert them to an electron shower which can be detected with conventional semiconductor or scintillator detectors. We've also begun development of technology that is designed to detect charged particles from neutron-capture reaction on 10B. The UCNtau experiment at the Los Alamos National Laboratories requires non-magnetic neutron sensors that can be used to measure the density of neutrons in a magnetic trap. We are employing a multilayer surface detector recently developed at Los Alamos for the UCN flux monitoring, adapting it for a compact, 1 cm2 detector and ultralow dark rates. The detector consists of 10B on ZnS scintillating sheet that will be adhered to both faces of an acrylic plate with scintillating optical fibers embedded into it. The optical fibers will be coupled to 2, Hamamatsu micro-PMTs for coincident detection of a neutron event.

  1. Beta-decay measurements of neutron-deficient cesium isotopes

    SciTech Connect

    Parry, R.F.

    1983-03-01

    Beta decay endpoint energy measurements of the neutron deficient cesium isotopes were done using an energy spectrum shape fitting technique. This was a departure from the typical method of endpoint energy analysis, the Fermi-Kurie plot. A discussion of the shape fitting procedure and its improved features are discussed. These beta endpoint measurements have led to total decay energies (Q/sub EC/) of the neutron deficient /sup 119/ /sup 123/Cs isotopes. The total decay energies of /sup 122m/Cs (Q/sub EC/ = 6.95 +- 0.25 MeV) and /sup 119/Cs (Q/sub EC/ = 6.26 +- 0.29 MeV) were new measurements. The total decay energies of /sup 123/Cs (Q/sub EC/ = 4.05 +- 0.18 MeV), /sup 122g/Cs (Q/sub EC/ = 7.05 +- 0.18 MeV), /sup 121/Cs (Q/sub EC/ = 5.21 +- 0.22 MeV), and /sup 120/Cs (Q/sub EC/ = 7.38 +- 0.23 MeV) were measurements with significantly improved uncertainties as compared to the literature. Further, a combination of the energy levels derived from previous literature gamma-gamma coincident measurements and the experimental beta-coincident gamma decay energies has supported an improved level scheme for /sup 121/Xe and the proposal of three new energy levels in /sup 119/Xe. Comparison of the experimental cesium mass excesses (determined with our Q/sub EC/ values and known xenon mass excesses) with both the literature and theoretical predicted values showed general agreement except for /sup 120/Cs. Possible explanations for this deviation are discussed.

  2. Double Beta Decays of 100Mo by ELEGANT V at Oto Cosmo Observatory

    NASA Astrophysics Data System (ADS)

    Kudomi, N.; Ejiri, H.; Fushimi, K.; Hayashi, K.; Kishimoto, T.; Kume, K.; Kuramoto, H.; Ohsumi, H.; Takahisa, K.; Tsujimoto, Y.; Yoshida, S.

    2003-04-01

    Exclusive measurements of neutrino-less double beta decays(0νββ) of 100Mo were made by means of ELEGANT V. The present status of the double beta decay experiment with ELEGANT V is presented. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on half-lives for 0νββ and < 1.8eV for the Majorana neutrino mass.

  3. Double beta decays of 100Mo by ELEGANT V at Oto Cosmo Observatory

    NASA Astrophysics Data System (ADS)

    Kudomi, N.; Ejiri, H.; Fushimi, K.; Hayashi, K.; Hazama, R.; Kishimoto, T.; Kume, K.; Kuramoto, H.; Matsuoka, T.; Ohsumi, H.; Takahisa, K.; Tsujimoto, Y.; Yoshida, S.

    2000-06-01

    Exclusive measurements of neutrino-less double beta decays (0νββ) of 100Mo were made by means of ELEGANT V. The present status of the double beta decay experiment with ELEGANT V is presented. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on half-lives for 0νββ and < mν> < 1.7eV.

  4. Molecular effects in the neutrino mass determination from beta-decay of the tritium molecule

    SciTech Connect

    Fackler, O.; Jeziorski, B.; Kolos, W.; Szalewicz, K.; Monkhorst, H.J.; Mugge, M.

    1986-03-01

    Molecular final state energies and transition probabilities have been computed for beta-decay of the tritium molecule. The results are of sufficient accuracy to make a determination of the electron neutrino rest mass with an error not exceeding a few tenths of an electron volt. Effects of approximate models of tritium beta-decay on the neutrino mass determination are discussed. 14 refs., 3 figs., 1 tab.

  5. Neutrinoless double beta decay in the left-right symmetric models for linear seesaw

    NASA Astrophysics Data System (ADS)

    Gu, Pei-Hong

    2016-09-01

    In a class of left-right symmetric models for linear seesaw, a neutrinoless double beta decay induced by the left- and right-handed charged currents together will only depend on the breaking details of left-right and electroweak symmetries. This neutrinoless double beta decay can reach the experimental sensitivities if the right-handed charged gauge boson is below the 100TeV scale.

  6. Signal modeling of high-purity Ge detectors with a small read-out electrode and application to neutrinoless double beta decay search in Ge-76

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Ur, C. A.; Budjáš, D.; Bellotti, E.; Brugnera, R.; Cattadori, C. M.; di Vacri, A.; Garfagnini, A.; Pandola, L.; Schönert, S.

    2011-03-01

    The GERDA experiment searches for the neutrinoless double beta decay of 76Ge using high-purity germanium detectors enriched in 76Ge. The analysis of the signal time structure provides a powerful tool to identify neutrinoless double beta decay events and to discriminate them from gamma-ray induced backgrounds. Enhanced pulse shape discrimination capabilities of Broad Energy Germanium detectors with a small read-out electrode have been recently reported. This paper describes the full simulation of the response of such a detector, including the Monte Carlo modeling of radiation interaction and subsequent signal shape calculation. A pulse shape discrimination method based on the ratio between the maximum current signal amplitude and the event energy applied to the simulated data shows quantitative agreement with the experimental data acquired with calibration sources. The simulation has been used to study the survival probabilities of the decays which occur inside the detector volume and are difficult to assess experimentally. Such internal decay events are produced by the cosmogenic radio-isotopes 68Ge and 60Co and the neutrinoless double beta decay of 76Ge. Fixing the experimental acceptance of the double escape peak of the 2.614 MeV photon to 90%, the estimated survival probabilities at Qββ = 2.039 MeV are (86+/-3)% for 76Ge neutrinoless double beta decays, (4.5+/-0.3)% for the 68Ge daughter 68Ga, and (0.9+0.4-0.2)% for 60Co decays.

  7. 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.

  8. 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

  9. Special features of the inverse-beta-decay reaction proceeding on a proton in a reactor-antineutrino flux

    NASA Astrophysics Data System (ADS)

    Kopeikin, V. I.; Skorokhvatov, M. D.

    2017-03-01

    The evolution of the reactor-antineutrino spectrum and the evolution of the spectrum of positrons from the inverse-beta-decay reaction in the course of reactor operation and after reactor shutdown are considered. The present-day status in determining the initial reactor-antineutrino spectrum on the basis of spectra of beta particles from mixtures of products originating from uranium and plutonium fission is described. A local rise of the experimental spectrum of reactor antineutrinos with respect to the expected spectrum is studied.

  10. 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.

  11. Evidence for the emission of a 17-keV neutrino in the. beta. decay of sup 14 C

    SciTech Connect

    Sur, B.; Norman, E.B.; Lesko, K.T.; Hindi, M.M.; Larimer, R.; Luke, P.N.; Hansen, W.L.; Haller, E.E. Department of Physics, Tennessee Technological University, Cookeville, Tennessee 38505 Engineering Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720)

    1991-05-13

    We have studied the {beta} spectrum of {sup 14}C using a germanium detector containing a crystal with {sup 14}C dissolved in it. We find a feature in the {beta} spectrum 17 keV below the end point which can be explained by the hypothesis that there is a heavy neutrino emitted in the {beta} decay of {sup 14}C with a mass of 17{plus minus}2 keV and an emission probability of (1.40{plus minus}0.45{plus minus}0.14)%.

  12. First results of a search for double beta decay of {sup 100}Mo with the NEMO 2 detector

    SciTech Connect

    NEMO Collaboration

    1993-06-15

    Double beta decay of {sup 100}Mo (172g) is studied with the NEMO 2 detector in the Frejus Underground Laboratory. The experiment has now accumulated 2485 hours of data taking. A clear signal of 380 events for 2{beta}2{nu} decay has been obtained corresponding to a half-life of T{sub {1/2}} = 1.0 {plus_minus} 0.08 (syst.) 10{sup 19} y. Limits are presented for 2{beta}(0{nu}, {chi}), 2{beta}0{nu} (ground state and excited states 2{sub 1}{sup +} and 0{sub 1}{sup +}). The experiment will run til October 1993.

  13. Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

    NASA Astrophysics Data System (ADS)

    Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

    2012-04-01

    The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

  14. Beta Decay Study of the T{sub z}=−2{sup 56}Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei

    SciTech Connect

    Rubio, B.; Orrigo, S.E.A.; Kucuk, L.; Montaner-Pizá, A.; Fujita, Y.; Fujita, H.; Blank, B.; Adachi, T.; Agramunt, J.; Algora, A.; Ascher, P.; Cáceres, L.; France, G. de; Gerbaux, M.; Giovinazzo, J.; Grevy, S. [CENBG, Université Bordeaux 1, UMR 5797 CNRS and others

    2014-06-15

    This paper concerns the experimental study of the β decay properties of few proton-rich fp-shell nuclei. The nuclei were produced at GANIL in fragmentation reactions, separated with the LISE spectrometer and stopped in an implantation detector surrounded by Ge detectors. The β-delayed gammas, β-delayed protons and the exotic β-delayed gamma-proton emission have been studied. Preliminary results are presented. The decay of the T{sub z}=−2 nucleus {sup 56}Zn has been studied in detail. Information from the β-delayed protons and β-delayed gammas has been used to deduce the decay scheme. The exotic beta-delayed gamma-proton decay has been observed for the first time in the fp-shell. The interpretation of the data was made possible thanks to the detailed knowledge of the mirror Charge Exchange (CE) process and the gamma de-excitation of the states in {sup 56}Co, the mirror nucleus of {sup 56}Cu.

  15. The MAJORANA DEMONSTRATOR: A Search for Neutrino less Double-beta Decay of Ge-76

    SciTech Connect

    Xu, W.; Abgrall, N.; Avignone, III, F. T.; Bertrand, F. E.; Efremenko, Yuri; Galindo-Uribarri, Alfredo {nmn}; Green, M. P.; Radford, D. C.; Romero-Romero, E.; White, B. R.; Wilkerson, J. F.

    2015-01-01

    Neutrino less double-beta (Ov beta beta) 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 Ov beta beta decay of Ge-76 and to demonstrate a background rate at or below 3 counts/ (ROI.t.y) in the 4 keV region of interest (ROT) around the 2039 keV Q-value for Ge-76 Ov beta beta 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.

  16. Second unique forbidden {beta} decay of {sup 115}In and neutrino mass

    SciTech Connect

    Dvornicky, R.; Simkovic, F.

    2011-12-16

    The measurement of the electron spectrum in {beta} decays close to the end point provides a robust direct determination of the values of neutrino masses. The most sensitive experiments use tritium and rhenium {beta} decays because these transitions have low Q value. Recent measurement with Penning traps established that the {beta} decay of {sup 115}In(9/2{sup +}) to the first excited state of {sup 115}Sn(3/2{sup +}) is a transition with the smallest Q value among {beta} decays. The decay is associated with a change of spin and parity {Delta}J{sup {pi}} = 3{sup +} ({Delta}L = 2, {Delta}S = 1) of nucleus, i.e., classified as unique second forbidden {beta} decay. Our investigation shows that in this transition electrons are predominantly emitted in d{sub 5/2} partial waves. In addition, it is found that the Kurie function associated with this transition near the end point within a good accuracy reflects a behavior the Kurie function of superallowed {beta} transitions.

  17. The Search for 17-KEV Neutrino Emission in the Beta-Decay Spectrum of SULFUR-35.

    NASA Astrophysics Data System (ADS)

    Berman, Gregg Evan

    For this work, the electron momentum spectrum resulting from the beta-decay of ^{35}S, ^{35}{rm S} to ^ {35}{rm Cl} + {rm e }^- + |nu_{rm e}quad (E_0 - m_{e} = 167 {rm keV, T}_{1/2 } = 87.4 {rm days}), has been measured in order to search for the presence of 17-keV electron neutrino emission. Originally observed by J. Simpson in 1985, evidence supporting a 1% 17-keV neutrino branch in the decay spectra of ^3 H, ^{35}S, ^{63}Ni, ^{55 }Fe, ^{14}C and ^{71}Ge has since been reported. However, other groups observing these nuclei have not seen any evidence of 17-keV neutrino emission, and very stringent limits ruling out a 1% branch have been published. Therefore, an important goal of this work is to reduce and/or understand experimental systematic errors that can mask or mimic the effects of a 17-keV neutrino. This ^{35}S spectrum measurement was performed using Princeton's extensively renovated, iron-free, intermediate-image, magnetic spectrometer. To ensure radio-chemical purity, the ^{35 }S source was prepared by ion-implantation using an isotope separator. To accurately determine the overall response of the spectrometer, electron data was accumulated over the very wide energy range of 40-167 keV. In addition, a detailed study of the spectrometer response using various ^{111}In calibration sources was undertaken, and the effects of source positioning and background magnetic fields have been explored. Furthermore, new computer codes for electron orbit raytracing and Monte-Carlo simulations have been developed to help further study the response of the spectrometer as well as to predict the effects of electron backscattering in both the source and detector substrates. To analyze the experimental data for the presence of a 17-keV neutrino branch, the measured ^ {35}S spectrum was convolved with the overall response of the spectrometer, and then fit by least -squares reduction to a theoretical beta -decay shape that allows heavy-neutrino mixing. The results show that the

  18. Shell model analysis of the neutrinoless double-{beta} decay of {sup 48}Ca

    SciTech Connect

    Horoi, Mihai; Stoica, Sabin

    2010-02-15

    The neutrinoless double-{beta} (0{nu}{beta}{beta}) decay process could provide crucial information to determine the absolute scale of neutrino masses, and it is the only one that can establish whether a neutrino is a Dirac or a Majorana particle. A key ingredient for extracting the absolute neutrino masses from 0{nu}{beta}{beta} decay experiments is a precise knowledge of the nuclear matrix elements (NMEs) describing the half-life of this process. We developed a shell model approach for computing the 0{nu}{beta}{beta} decay NME, and we used it to analyze the 0{nu}{beta}{beta} mode of {sup 48}Ca. The dependence of the NME on the short-range correlation parameters, on the average energy of the intermediate states, on the finite-size cutoff parameters, and on the effective interaction used for many-body calculations is discussed.

  19. Observation of the acceleration by an electromagnetic field of nuclear beta decay

    NASA Astrophysics Data System (ADS)

    Reiss, H. R.

    2008-02-01

    Measurements are reported of the acceleration of the first-forbidden beta decay of 137Cs by exposure to intense, low-frequency electromagnetic fields. Two separate experiments were done: one in a coaxial cavity, and the other in a coaxial transmission line. The first showed an increase in the beta decay rate of (6.8±3.2)×10-4 relative to the natural rate, and the other resulted in an increase of (6.5±2.0)×10- 4. In addition, a Fourier analysis of the rate of 662 keV gamma emission following from the beta decay in the standing-wave experiment showed a clear indication of the frequency with which the external field was switched on and off. A simultaneously detected gamma emission from a placebo nucleus showed no such peak.

  20. Maria Goeppert Mayer's work on beta-decay and pairing, and its relevance today

    NASA Astrophysics Data System (ADS)

    Moszkowski, Steven

    2013-04-01

    Maria Goeppert Mayer's work on beta-decay and pairing is not as well known as her Nobel Prize winning work on the nuclear shell model, but it attests to her wide range of accomplishments. Her paper on double beta decay was the first one written on the subject. Later she also worked on the application of beta decay as a test of the nuclear shell model. Due to its very long half-life, double beta-decay was not found experimentally until the 1980's. This involves emission of two neutrinos along with the two electrons. However, in principle it is also possible to have double beta decay with no neutrinos, a process which was identified about 10 years ago, though this is still quite controversial. Currently, there are several groups working on this problem, which has significant implications for particle physics and for cosmology. It was known from the earliest days of nuclear physics that nuclei with even Z and even N are more stable than others due to the pairing effect. Indeed, all nuclei in which double beta-decay is looked for are even-even and this would not be possible were it not for pairing. In MGM's paper on pairing, published shortly after the ones on the magic numbers and role of spin-orbit coupling, she used a very simplified zero range nuclear interaction. There has been considerable work on pairing in the meantime. It is still an open problem how to understand the details of how pairing works in nuclei, in terms of realistic nucleon-nucleon interactions.

  1. Double Beta Decays of 100Mo by ELEGANT V at Oto Cosmo Observatory

    NASA Astrophysics Data System (ADS)

    Kudomi, N.; Ejiri, H.; Fushimi, K.; Hayashi, K.; Hazama, R.; Kishimoto, T.; Kume, K.; Kuramoto, H.; Matsuoka, T.; Ohsumi, H.; Takahisa, K.; Tsujimoto, Y.; Yoshida, S.

    2002-09-01

    Exclusive measurements of neutrino-less double beta decays (0νββ) of 100Mo were made by means of ELEGANT V. ELEGANT V was moved to Oto Cosmo Observatory from Kamioka underground lab. The present status of the double beta decay experiment with ELEGANT V is presented. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on half-lives for 0νββ and < 1.9eV for the Majorana neutrino mass.

  2. Tracking electrons from double beta decay - How far can you push the TPC?

    NASA Astrophysics Data System (ADS)

    Moe, M. K.; Nelson, M. A.; Vient, M. A.

    New results are reported from time-projection-chamber measurements of the double beta decay of 100Mo and 150Nd. A previously-observed high-energy anomaly has been eliminated by improved energy resolution. Kurie plots of the two-neutrino spectra show end-point energies close to the reported parent-daughter mass differences. The 150Nd source has produced a new direct-counting 90% confidence neutrino-majoron coupling limit of < gν, χ> < 7.0 × 10 -5. The strengths and weaknesses of the TPC, and the feasibility of a larger TPC for neutrinoless double beta decay are discussed.

  3. Determination of the weak magnetism matrix element in {sup 14}C beta decay

    SciTech Connect

    Zeuli, A.R.; Ahmad, I.; Coulter, K.P.; Greene, J.P.; Schiffer, J.P.; Freedman, S.J.; Fujikawa, B.K.; Mortara, J.L.

    1993-10-01

    Higher order beta decay matrix elements, such as weak magnetism, will introduce small departures (a shape factor) from the allowed beta decay electron energy spectrum. The value of the weak magnetism matrix element is predicted by the Conserved Vector Current (CVC) hypothesis and an experimental determination of the weak magnetism matrix element can be interpreted as a test of CVC. We have determined the weak magnetism matrix element from the {sup 14}C shape factor, which was measured using an apparatus incorporating a high resolution solid state detector and a super conducting solenoid. The results of our measurement will be presented.

  4. 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.

  5. 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.

  6. The influence of pairing correlations on the isospin symmetry breaking corrections of superallowed Fermi beta decays

    SciTech Connect

    Cal Latin-Small-Letter-Dotless-I k, A. E.; Gerceklioglu, M.; Selam, C.

    2013-05-15

    Within the framework of quasi-particle random phase approximation, the isospin breaking correction of superallowed 0{sup +} {yields} 0{sup +} beta decay and unitarity of Cabibbo-Kobayashi-Maskawa mixing matrix have been investigated. The broken isotopic symmetry of nuclear part of Hamiltonian has been restored by Pyatov's method. The isospin symmetry breaking correction with pairing correlations has been compared with the previous results without pairing. The effect of pairing interactions has been examined for nine superallowed Fermi beta decays; their parent nuclei are {sup 26}Al, {sup 34}Cl, {sup 38}K, {sup 42}Sc, {sup 46}V, {sup 50}Mn, {sup 54}Co, {sup 62}Ga, {sup 74}Rb.

  7. 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.

  8. beta-decay properties of neutron-rich Zr and Mo isotopes

    SciTech Connect

    Sarriguren, P.; Pereira, J.

    2010-06-15

    Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron emission are investigated in neutron-rich Zr and Mo isotopes within a deformed quasiparticle random-phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. Comparison with recent measurements of half-lives stresses the important role that nuclear deformation plays in the description of beta-decay properties in this mass region.

  9. 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.

  10. Line-shape analysis of Doppler-broadened {gamma} lines following the {beta} decay of {sup 11}Li

    SciTech Connect

    Mattoon, C. M.; Sarazin, F.; Andreoiu, C.; Cross, D.; Ressler, J. J.; Andreyev, A. N.; Ball, G. C.; Chakrawarthy, R. S.; Cunningham, E. S.; Daoud, J.; Hackman, G.; Morton, C.; Pearson, C.; Smith, M. B.; Austin, R. A. E.; Garrett, P. E.; Grinyer, G. F.; Svensson, C. E.; Melconian, D.; Schwarzenberg, J.

    2009-09-15

    The {beta} decay of {sup 11}Li is studied at the TRIUMF Isotope Separation and Acceleration (ISAC) facility using the 8{pi} {gamma}-ray spectrometer coupled with an inner array of 20 plastic scintillators for {beta} detection. Doppler-broadened line shapes resulting from the decay of the excited states in {sup 10}Be populated by {beta}-delayed one-neutron emission are analyzed using Monte Carlo simulations. New {beta}-delayed neutron decay branches are shown to contribute to the complex decay of {sup 11}Li. The half-lives of all but one bound excited state in {sup 10}Be are also deduced from this work. Among them, the half-life of the 2{sup -} state in {sup 10}Be is shown to be much shorter than previously thought, yielding a new experimental B(E1) now well within the range of theoretical predictions and providing further evidence that the 2{sup -} state in {sup 10}Be is an excited halo state. The nature of the 8.82-MeV state in {sup 11}Be and its decay paths to excited states in {sup 10}Be are found to be consistent with the {beta} decay of the core proceeding through this particular state.

  11. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Decoding {beta}-decay systematics: A global statistical model for {beta}{sup -} half-lives

    SciTech Connect

    Costiris, N. J.; Mavrommatis, E.; Gernoth, K. A.; Clark, J. W.

    2009-10-15

    Statistical modeling of nuclear data provides a novel approach to nuclear systematics complementary to established theoretical and phenomenological approaches based on quantum theory. Continuing previous studies in which global statistical modeling is pursued within the general framework of machine learning theory, we implement advances in training algorithms designed to improve generalization, in application to the problem of reproducing and predicting the half-lives of nuclear ground states that decay 100% by the {beta}{sup -} mode. More specifically, fully connected, multilayer feed-forward artificial neural network models are developed using the Levenberg-Marquardt optimization algorithm together with Bayesian regularization and cross-validation. The predictive performance of models emerging from extensive computer experiments is compared with that of traditional microscopic and phenomenological models as well as with the performance of other learning systems, including earlier neural network models as well as the support vector machines recently applied to the same problem. In discussing the results, emphasis is placed on predictions for nuclei that are far from the stability line, and especially those involved in r-process nucleosynthesis. It is found that the new statistical models can match or even surpass the predictive performance of conventional models for {beta}-decay systematics and accordingly should provide a valuable additional tool for exploring the expanding nuclear landscape.

  13. 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.

  14. Pulse-shape discrimination techniques for the COBRA double beta-decay experiment at LNGS

    NASA Astrophysics Data System (ADS)

    Zatschler, S.; COBRA collaboration

    2017-09-01

    In modern elementary particle physics several questions arise from the fact that neutrino oscillation experiments have found neutrinos to be massive. Among them is the so far unknown nature of neutrinos: either they act as so-called Majorana particles, where one cannot distinguish between particle and antiparticle, or they are Dirac particles like all the other fermions in the Standard Model. The study of neutrinoless double beta-decay (0νββ-decay), where the lepton number conservation is violated by two units, could answer the question regarding the underlying nature of neutrinos and might also shed light on the mechanism responsible for the mass generation. So far there is no experimental evidence for the existence of 0νββ-decay, hence, existing experiments have to be improved and novel techniques should be explored. One of the next-generation experiments dedicated to the search for this ultra-rare decay is the COBRA experiment. This article gives an overview of techniques to identify and reject background based on pulse-shape discrimination.

  15. 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.

  16. Radiopurity assessment of the energy readout for the NEXT double beta decay experiment

    NASA Astrophysics Data System (ADS)

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

    2017-08-01

    The "Neutrino Experiment with a Xenon Time-Projection Chamber" (NEXT) experiment intends to investigate the neutrinoless double beta decay of 136Xe, and therefore requires a severe suppression of potential backgrounds. An extensive material screening and selection process was undertaken to quantify the radioactivity of the materials used in the experiment. Separate energy and tracking readout planes using different sensors allow us to combine the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. The design of radiopure readout planes, in direct contact with the gas detector medium, was especially challenging since the required components typically have activities too large for experiments demanding ultra-low background conditions. After studying the tracking plane, here the radiopurity control of the energy plane is presented, mainly based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain). All the available units of the selected model of photomultiplier have been screened together with most of the components for the bases, enclosures and windows. According to these results for the activity of the relevant radioisotopes, the selected components of the energy plane would give a contribution to the overall background level in the region of interest of at most 2.4×10-4 counts keV-1 kg-1 y-1, satisfying the sensitivity requirements of the NEXT experiment.

  17. LBL/UCSB /sup 76/Ge double beta decay experiment: first results

    SciTech Connect

    Goulding, F.S.; Cork, C.P.; Landis, D.A.; Luke, P.N.; Madden, N.W.; Malone, D.F.; Pehl, R.H.; Smith, A.R.; Caldwell, D.O.; Eisberg, R.M.

    1984-10-01

    A paper given at the IEEE Nuclear Science Symposium last year presented the scientific justification for this experiment and discussed the design of the detector system. At the present time two of the dual detector systems (i.e., four out of a final total of eight detectors) are operating in the complete active/passive shield in the low background laboratory at LBL. Early results (1620 h) of an experiment using two detectors yield a limit of 4 x 10/sup 22/ years (68% confidence) for the half life of the neutrinoless double beta decay (..beta beta../sub o nu/) of /sup 76/Ge. Although this experiment was carried out above ground, the result approaches those achieved by other groups in deep underground laboratories. Based on studies of the origins of background in our system, we hope to reach a limit of 3 x 10/sup 23/ years (or more) in a two month/four detector experiment to be carried out soon in an underground facility.

  18. Neutrinoless double beta decay in LRSM with natural type-II seesaw dominance

    NASA Astrophysics Data System (ADS)

    Pritimita, Prativa; Dash, Nitali; Patra, Sudhanwa

    2016-10-01

    We present a detailed discussion on neutrinoless double beta decay within a class of left-right symmetric models where neutrino mass originates by natural type-II seesaw dominance. The spontaneous symmetry breaking is implemented with doublets, triplets and bidoublet scalars. The fermion sector is extended with an extra sterile neutrino per generation that helps in implementing the seesaw mechanism. The presence of extra particles in the model exactly cancels type-I seesaw and allows large value for Dirac neutrino mass matrix M D . The key feature of this work is that all the physical masses and mixing are expressed in terms of neutrino oscillation parameters and lightest neutrino mass thereby facilitating to constrain light neutrino masses from 0ν ββ decay. With this large value of M D new contributions arise due to; i) purely left-handed current via exchange of heavy right- handed neutrinos as well as sterile neutrinos, ii) the so called λ and η diagrams. New physics contributions also arise from right-handed currents with right-handed gauge boson W R mass around 3 TeV. From the numerical study, we find that the new contributions to 0 νββ decay not only saturate the current experimental bound but also give lower limit on absolute scale of lightest neutrino mass and favor NH pattern of light neutrino mass hierarchy.

  19. Measurement of the two-neutrino double-beta decay half-life of $^{130}$ Te with the CUORE-0 experiment

    SciTech Connect

    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.; 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.; D’Addabbo, A.; Dafinei, I.; Davis, C. J.; Dell’Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Feintzeig, J.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; 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.; Leder, A.; Ligi, C.; 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.; Napolitano, T.; 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.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; 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.

    2017-01-01

    We report on the measurement of the two-neutrino double-beta decay half-life of 130 Te with the CUORE-0 detector. From an exposure of 33.4 kg year of TeO 22 , the half-life is determined to be T$2ν\\atop{1/2}$ = [8.2 ± 0.2 (stat.) ± 0.6 (syst.)] ×× 10 20 year. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the 130130 Te neutrinoless double-beta decay region of interest.

  20. What neutrinoless double beta decay would tell us about neutrino mass

    SciTech Connect

    Kayser, B. )

    1992-02-01

    We identify several types of gauge theories, which together comprise a very broad range, in which the observation of neutrinoless double beta decay would imply a significant lower bound on neutrino mass. We explain why these gauge theories have this property.

  1. Status of the Battelle-Carolina /sup 76/Ge double beta decay experiment

    SciTech Connect

    Moore, R.S.; Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1983-09-01

    A new detector for the measurement of /sup 76/Ge double beta decay is described. The detector system will consist of a 1440 cm/sup 3/ mosaic Ge detector with anticoincidence shielding, and the experiment will be performed deep underground. 12 references. (WHK)

  2. 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.

  3. About some of the theoretical approaches used in double-beta decay calculations

    SciTech Connect

    Civitarese, O.

    2007-10-12

    The calculations of nuclear matrix elements, corresponding to nuclear double beta decay transitions, rely upon several approximations. The impact of these approximations upon final estimations of the nuclear matrix elements is illustrated. We pay attention to mean field (symmetry violations) and to approximate diagonalizations (pn-QRPA, renormalized pn-QRPA and fully renormalized pn-QRPA)

  4. About some of the theoretical approaches used in double-beta decay calculations

    NASA Astrophysics Data System (ADS)

    Civitarese, O.

    2007-10-01

    The calculations of nuclear matrix elements, corresponding to nuclear double beta decay transitions, rely upon several approximations. The impact of these approximations upon final estimations of the nuclear matrix elements is illustrated. We pay attention to mean field (symmetry violations) and to approximate diagonalizations (pn-QRPA, renormalized pn-QRPA and fully renormalized pn-QRPA).

  5. I. Atomic Effects in Tritium Beta-Decay II. Muon to Electron Conversion in Atoms.

    NASA Astrophysics Data System (ADS)

    Wampler, Kevin Dean

    I. The final-state, atomic effects in the low energy end of the tritium beta decay spectrum are studied in detail. I treat the instantaneous, two-electron repulsion in the final state, effectively to all orders in perturbation theory, by solving the eigenvalue problem with a discretized and truncated form of the Hamiltonian. I find that these effects fail to explain the distortion in the spectrum observed by Simpson (Phys. Rev. Lett. 54, 649 (1985)). Simpson attributed this distortion to the admixture of a heavy mass antineutrino in the outgoing electron antineutrino state. In fact, the final-state Coulomb effects enhance the distortion. This calculation clears up some of the ambiguities of other theoretical analyses based on considerations of screening functions and perturbation theory. II. I present a phenomenological study of separate lepton number violating muon to electron conversion in atoms. Previous work on this process has concentrated on elastic transitions where the nucleus remains in the ground state. I present an analysis of the branching ratios of inelastic to elastic transitions. This analysis uses realistic muon wavefunctions and electron plane waves. A multipole analysis is used for the nuclear matrix elements. The particular case of ^{32}S is studied in detail. It is found that, if anomalous muon capture occurs, the coherent (ground-state to ground-state) transition dominates the rate, if this transition is allowed by the coupling constants. However, incoherent (excited state) transitions could be significant in some cases, particularly if coupling to the nuclear pseudo-scalar current occurs, and would permit one to obtain stringent limits on the corresponding couplings that mediate muon number violation.

  6. {beta} decay of proton-rich nucleus {sup 23}Al and astrophysical consequences

    SciTech Connect

    Iacob, V. E.; Zhai, Y.; Al-Abdullah, T.; Fu, C.; Hardy, J. C.; Nica, N.; Park, H. I.; Tabacaru, G.; Trache, L.; Tribble, R. E.

    2006-10-15

    We present the first study of the {beta} decay of {sup 23}Al undertaken with pure samples. The study was motivated by nuclear astrophysics questions. Pure samples of {sup 23}Al were obtained from the momentum achromat recoil separator (MARS) of Texas A and M University, collected on a fast tape-transport system, and moved to a shielded location where {beta} and {beta}-{gamma} coincidence measurements were made. We deduced {beta} branching ratios and log ft values for transitions to states in {sup 23}Mg, and from them determined unambiguously the spin and parity of the {sup 23}Al ground state to be J{sup {pi}}=5/2{sup +}. We discuss how this excludes the large increases in the radiative proton capture cross section for the reaction {sup 22}Mg(p,{gamma}){sup 23}Al at astrophysical energies, which were implied by claims that the spin and parity is J{sup {pi}}=1/2{sup +}. The log ft for the Fermi transition to its isobaric analog state (IAS) in {sup 23}Mg is also determined for the first time. This IAS and a state 16 keV below it are observed, well separated in the same experiment for the first time. We can now solve a number of inconsistencies in the literature, exclude strong isospin mixing claimed before, and obtain a new determination of the resonance strength. Both states are resonances in the {sup 22}Na(p,{gamma}){sup 23}Mg reaction at energies important in novae. The reactions {sup 22}Mg(p,{gamma}){sup 23}Al and {sup 22}Na(p,{gamma}){sup 23}Mg have both been suggested as possible candidates for diverting some of the flux in oxygen-neon novae explosions from the A=22 into the A=23 mass 0011cha.

  7. Monte Carlo Simulations of Scattering and Energy Loss in Beta Decay for the Nab and UCNB Experiments

    NASA Astrophysics Data System (ADS)

    Wexler, Jonathan; Nab Collaboration; UCNB Collaboration

    2017-01-01

    Measurements of beta decay spectra are sensitive to both Standard Model physics and modifications of the Standard Model through extraction of correlation parameters. Extraction of these parameters requires accurate energy reconstruction of measured particles stemming a precise understanding of the energy loss. Simulations of neutron decay products in a magnetic spectrometer, per the design of the UCNB and Nab experiments, and energy collection in thick, segmented silicon wafer detectors have been performed to probe the effects of silicon dead layers, sub-threshold events, bremsstrahlung in order to generate Monte Carlo corrections from the simulated spectra. In addition, simulations with sources implanted on foils allow characterization of the detector response and performing fundamental weak interaction studies, such as measuring the beta spectra from 45Ca decays. We present an overview of simulations for the UCNB and Nab experiments as well as the current status of the Monte Carlo corrections.

  8. Extending two Higgs doublet models for two-loop neutrino mass generation and one-loop neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Gu, Pei-Hong

    2017-02-01

    We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.

  9. 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.

  10. Influence of the tritium beta(-) decay on low-temperature thermonuclear burn-up in deuterium-tritium mixtures

    PubMed

    Frolov

    2000-09-01

    Low-temperature (Tstudied for the critical burn-up parameter x(c)=rhor(c) upon the initial temperature T, density rho(0), and tritium molar concentration y for the [D]:y[T]:(1-y)[3He] mixture. In particular, it is shown that, if the tritium concentration y decreases, then the critical burn-up parameter x(c)(T,rho(0),y) grows very quickly (at fixed T and rho(0)). This means that tritium beta(-) decay significantly complicates thermonuclear burn-up in deuterium-tritium mixtures.

  11. 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.

  12. Search for Neutrinoless Double-Beta Decay in Xe136 with EXO-200

    NASA Astrophysics Data System (ADS)

    Auger, M.; Auty, D. J.; Barbeau, P. S.; Beauchamp, E.; Belov, V.; Benitez-Medina, C.; Breidenbach, M.; Brunner, T.; Burenkov, A.; Cleveland, B.; Cook, S.; Daniels, T.; Danilov, M.; Davis, C. G.; Delaquis, S.; deVoe, R.; Dobi, A.; Dolinski, M. J.; Dolgolenko, A.; Dunford, M.; Fairbank, W., Jr.; Farine, J.; Feldmeier, W.; Fierlinger, P.; Franco, D.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Hall, C.; Hall, K.; Hargrove, C.; Herrin, S.; Hughes, M.; Johnson, A.; Johnson, T. N.; Karelin, A.; Kaufman, L. J.; Kuchenkov, A.; Kumar, K. S.; Leonard, D. S.; Leonard, F.; Mackay, D.; MacLellan, R.; Marino, M.; Mong, B.; Montero Díez, M.; Müller, A. R.; Neilson, R.; Nelson, R.; Odian, A.; Ostrovskiy, I.; O'Sullivan, K.; Ouellet, C.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rowson, P. C.; Russell, J. J.; Sabourov, A.; Sinclair, D.; Slutsky, S.; Stekhanov, V.; Tolba, T.; Tosi, D.; Twelker, K.; Vogel, P.; Vuilleumier, J.-L.; Waite, A.; Walton, T.; Weber, M.; Wichoski, U.; Wodin, J.; Wright, J. D.; Yang, L.; Yen, Y.-R.; Zeldovich, O. Ya.

    2012-07-01

    We report on a search for neutrinoless double-beta decay of Xe136 with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ˜1.5×10-3kg-1yr-1keV-1 in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T1/20νββ(Xe136)>1.6×1025yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.

  13. Search for neutrinoless double-beta decay in 136Xe with EXO-200.

    PubMed

    Auger, M; Auty, D J; Barbeau, P S; Beauchamp, E; Belov, V; Benitez-Medina, C; Breidenbach, M; Brunner, T; Burenkov, A; Cleveland, B; Cook, S; Daniels, T; Danilov, M; Davis, C G; Delaquis, S; deVoe, R; Dobi, A; Dolinski, M J; Dolgolenko, A; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Franco, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Hall, C; Hall, K; Hargrove, C; Herrin, S; Hughes, M; Johnson, A; Johnson, T N; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Mackay, D; MacLellan, R; Marino, M; Mong, B; Montero Díez, M; Müller, A R; Neilson, R; Nelson, R; Odian, A; Ostrovskiy, I; O'Sullivan, K; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rowson, P C; Russell, J J; Sabourov, A; Sinclair, D; Slutsky, S; Stekhanov, V; Tolba, T; Tosi, D; Twelker, K; Vogel, P; Vuilleumier, J-L; Waite, A; Walton, T; Weber, M; Wichoski, U; Wodin, J; Wright, J D; Yang, L; Yen, Y-R; Zeldovich, O Ya

    2012-07-20

    We report on a search for neutrinoless double-beta decay of 136Xe with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ∼1.5×10(-3)  kg(-1) yr(-1)  keV(-1) in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νββ)(136Xe)>1.6×10(25)  yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.

  14. Correlation measurements in nuclear {beta}-decay using traps and polarized low energy beams

    SciTech Connect

    Naviliat-Cuncic, Oscar

    2013-05-06

    Precision measurements in nuclear {beta}-decay provide sensitive means to test discrete symmetries in the weak interaction and to determine some of the fundamental constants in semi-leptonic decays, like the coupling of the lightest quarks to charged weak bosons. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. In this contribution I will focus on two topics related to precision measurements in nuclear {beta}-decay: i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and ii) the search for exotic scalar or tensor contributions from {beta}{nu} angular correlations. The purpose is to underline the role being played by experimental techniques based on the confinement of radioactive species with atom and ion traps as well as the plans to use low energy polarized beams.

  15. Electron capture decay of {sup 116}In and nuclear structure of double {beta} decays

    SciTech Connect

    Bhattacharya, M.; Garcia, A.; Ortiz, C.E.; Kaloskamis, N.I.; Hindi, M.M.; Norman, E.B.; Davids, C.N.; Civitarese, O.; Suhonen, J.

    1998-08-01

    Quasiparticle-random-phase-approximation (QRPA) calculations of double {beta} decays have not been able to reproduce data in the A=100 system. We propose the A=116 system{emdash}because of its smaller deformation{emdash}as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of {sup 116}In to be (2.27{plus_minus}0.63){times}10{sup {minus}2}{percent}, from which we deduce logft=4.39{sub {minus}0.15}{sup +0.10}. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2{nu} double-{beta}-decay rate of {sup 116}Cd to the ground and excited states of {sup 116}Sn. {copyright} {ital 1998} {ital The American Physical Society}

  16. The next generation neutrinoless double-beta decay experiment nEXO

    NASA Astrophysics Data System (ADS)

    MacLellan, Ryan; nEXO Collaboration

    2017-01-01

    The nEXO Collaboration is actively engaged in R&D towards a very large detector for neutrinoless double beta decay of 136Xe. The nEXO detector is rooted in the current EXO-200 program, which has reached a sensitivity for the half-life of the decay of 1 . 9 ×1025 y with an exposure of 99.8 kg-y. The baseline nEXO design assumes 5 tonnes of liquid xenon, enriched in the mass 136 isotope, within a large monolithic time projection chamber. The initial goal for nEXO is a neutrinoless double-beta decay half-life sensitivity of 1 ×1028 y, covering the inverted neutrino mass hierarchy with 5 years of data. We present the conceptual nEXO detector design, the current status of R&D efforts, and the physics case for the experiment.

  17. 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.

  18. Beta-Decay and Delayed Neutron Emission of Very Neutron-Rich Nuclei

    NASA Astrophysics Data System (ADS)

    Borzov, I. N.

    2014-09-01

    Extended self-consistent beta-decay model has been applied for beta-decay rates and delayed multi-neutron emission probabilities of quasi-spherical neutron-rich isotopes. The Gamow-Teller and first-forbidden decays are treated within the coordinate-space formalism of the continuum QRPA based on the density functional theory description of the ground state. A new set of the Fayans density functional parameters (DF3a) have been employed giving a better spin-orbit splitting due to a stronger tensor term. A provision has been included to fix the odd particle in the proper orbit (before variation). This accounts for ground-state spin inversion effect which has been shown to exist in the region of the most neutron-rich doubly-magic nucleus 78Ni.

  19. Beta-decay half-lives and level ordering of 102m,gRh.

    PubMed

    Shibata, M; Satoh, Y; Itoh, S; Yamamoto, H; Kawade, K; Kasugai, Y; Ikeda, Y

    1998-12-01

    Beta-decay half-lives of the ground state and an isomer of 102Rh have been determined 207.3(17) d and 3,742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2-) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.

  20. Electron Shake-up and Shake-off Following 6He Beta Decay

    NASA Astrophysics Data System (ADS)

    Schulhoff, Eva; Drake, G. W. F.

    2016-03-01

    Probabilities for electron shake-up and shake-off are calculated as relaxation processes following the beta decay of 6He to form 6Li, including corrections due to nuclear recoil. Within the sudden approximation, it is found that the correction due to nuclear recoil is nearly an order of magnitude less than that measured by Carlson et al. Phys. Rev. 129, 2220 (1963).

  1. Five Sample Proposals for Next Generation Neutrinoless Double-Beta Decay Experiments

    NASA Astrophysics Data System (ADS)

    Avignone, F. T., III; King, G. S., III

    2005-06-01

    Five next generation zero-neutrino double-beta decay experimental proposals are discussed. They propose to utilize cryogenic, ionization, time-projection chamber, and tracking chamber techniques. The representative experiments are: CUORE/CUORICINO, EXO, Majorana, MOON, and NEMO. We make no claim that this selection of experiments is the best or in any way a complete listing. It is limited by the available space.

  2. 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.

  3. Calculating beta decay in the deformed self-consistent quasiparticle random phase approximation

    SciTech Connect

    Engel, Jonathan; Mustonen, M. T.

    2016-06-21

    We discuss a recent global calculation of beta-decay rates in the self-consistent Skyrme quasiparticle random phase approximation (QRPA), with axially symmetric nuclear deformation treated explicitly. The calculation makes makes use of the finite-amplitude method, first proposed by Nakatsukasa and collaborators, to reduce computation time. The results are comparable in quality to those of several other global QRPA calculations. The QRPA may have reached the limit of its accuracy.

  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. Single molecule fluorescence imaging as a technique for barium tagging in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Jones, B. J. P.; McDonald, A. D.; Nygren, D. R.

    2016-12-01

    Background rejection is key to success for future neutrinoless double beta decay experiments. To achieve sensitivity to effective Majorana lifetimes of ~ 1028 years, backgrounds must be controlled to better than 0.1 count per ton per year, beyond the reach of any present technology. In this paper we propose a new method to identify the birth of the barium daughter ion in the neutrinoless double beta decay of 136Xe. The method adapts Single Molecule Fluorescent Imaging, a technique from biochemistry research with demonstrated single ion sensitivity. We explore possible SMFI dyes suitable for the problem of barium ion detection in high pressure xenon gas, and develop a fiber-coupled sensing system with which we can detect the presence of bulk Ba++ ions remotely. We show that our sensor produces signal-to-background ratios as high as 85 in response to Ba++ ions when operated in aqueous solution. We then describe the next stage of this R&D program, which will be to demonstrate chelation and fluorescence in xenon gas. If a successful barium ion tag can be developed using SMFI adapted for high pressure xenon gas detectors, the first essentially zero background, ton-scale neutrinoless double beta decay technology could be realized.

  6. 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.

  7. First results on 76Ge neutrinoless double beta decay from CDEX-1 experiment

    NASA Astrophysics Data System (ADS)

    Wang, Li; Yue, Qian; Kang, KeJun; Cheng, JianPing; Li, YuanJing; Wong, TszKing Henry; Lin, ShinTed; Chang, JianPing; Chen, JingHan; Chen, QingHao; Chen, YunHua; Deng, Zhi; Du, Qiang; Gong, Hui; He, Li; He, QingJu; Hu, JinWei; Huang, HanXiong; Huang, TengRui; Jia, LiPing; Jiang, Hao; Li, HauBin; Li, Hong; Li, JianMin; Li, Jin; Li, Jun; Li, Xia; Li, XueQian; Li, YuLan; Lin, FongKay; Liu, ShuKui; Ma, Hao; Ma, JingLu; Pan, XingYu; Ren, Jie; Ruan, XiChao; Shen, ManBin; Sharma, Vivek; Singh, Lakhwinder; Singh, Manoj Kumar; Singh, Manoj Kumar; Soma, Arun Kumar; Tang, ChangJian; Tang, WeiYou; Tseng, ChaoHsiung; Wang, JiMin; Wang, Qing; Wu, ShiYong; Wu, YuCheng; Xing, HaoYang; Xu, Yin; Xue, Tao; Yang, LiTao; Yang, SongWei; Yi, Nan; Yu, ChunXu; Yu, HaiJun; Zeng, WeiHe; Zeng, XiongHui; Zeng, Zhi; Zhang, Lan; Zhang, YunHua; Zhao, MingGang; Zhao, Wei; Zhou, JiFang; Zhou, ZuYing; Zhu, JingJun; Zhu, WeiBin; Zhu, ZhongHua

    2017-07-01

    We report the first results on 76Ge neutrinoless double beta decay from stage one of the China dark-matter experiment (CDEX). A p-type point-contact high-purity germanium detector with a mass of 994 g has been installed to detect neutrinoless double beta decay events, as well as to directly detect dark matter particles. An exposure of 304 kg d has been analyzed over a wide spectral band from 500 keV to 3 MeV. The average event rate obtained was about 0.012 counts per keV per kg per day over the 2.039 MeV energy range. The half-life of 76Ge neutrinoless double beta decay derived based on this result is T 1/2 0ν >6.4×1022 yr (90% C.L.). An upper limit on the effective Majorana-neutrino mass of 5.0 eV has been achieved.

  8. 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.

  9. Analytic heating rate of neutron star merger ejecta derived from Fermi's theory of beta decay

    NASA Astrophysics Data System (ADS)

    Hotokezaka, Kenta; Sari, Re'em; Piran, Tsvi

    2017-06-01

    Macronovae (kilonovae) that arise in binary neutron star mergers are powered by radioactive beta decay of hundreds of r-process nuclides. We derive, using Fermi's theory of beta decay, an analytic estimate of the nuclear heating rate. We show that the heating rate evolves as a power law ranging between t-6/5 and t-4/3. The overall magnitude of the heating rate is determined by the mean values of nuclear quantities, e.g. the nuclear matrix elements of beta decay. These values are specified by using nuclear experimental data. We discuss the role of higher order beta transitions and the robustness of the power law. The robust and simple form of the heating rate suggests that observations of the late-time bolometric light curve ∝ t-4/3 would be direct evidence of a r-process driven macronova. Such observations could also enable us to estimate the total amount of r-process nuclei produced in the merger.

  10. [sup 223]Ra levels fed in the [sup 223]Fr [beta] decay

    SciTech Connect

    Abdul-Hadi, A.; Barci, V.; Weiss, B.; Maria, H.; Ardisson, G. ); Hussonnois, M.; Constantinescu, O. )

    1993-01-01

    The [sup 223]Fr [beta] decay was reinvestigated using high-resolution single [gamma] spectrometry as well as [gamma]-[gamma] coincidence techniques. For single [gamma]-spectra measurements, radiochemically pure [sup 223]Fr sources were obtained by chromatographic separation from a 75 MBq activity [sup 227]Ac parent source and continuously purified of [sup 223]Ra and daughters. The analysis of the [gamma] spectra of 30 sources showed the existence of 131 [gamma] lines, of which 87 are reported for the first time in the [sup 223]Fr [beta] decay although many of them are observed following the [sup 227]Th [alpha] decay. The [sup 223]Fr half-life was remeasured and found to be [ital T][sub 1/2]=22.00[plus minus]0.07 min. [gamma]-[gamma]-[ital t] coincidence measurements were also carried out with [sup 223]Fr purified sources. The [sup 223]Ra level scheme was built on the basis of our [gamma] data, as well as [sup 227]Th [alpha]-decay data. Among the 32 excited [sup 223]Ra levels, of which 22 were also known from [sup 227]Th [alpha] decay, 13 are newly reported from [sup 223]Fr [beta] decay. Low energy levels ([ital E][lt]400 keV) may be classified as parity doublet bands according to the predictions of the reflection asymmetric rotor model. Above a 700 keV gap, a coexistence of symmetric and asymmetric shapes including both static and dynamic octupole correlations is suggested.

  11. Complex beta-decay schemes: Pandemonium lost and paradise regained

    NASA Astrophysics Data System (ADS)

    Firestone, R. B.

    1982-06-01

    The β-decay of 145Gd has been studied in sufficient detail for comparison with the decay of its fictional analogue Pandemonium. It is shown that >98% of the 145Gd decay intensity was observed. This result casts doubt on the value of decay schemes determined solely by statistical techniques.

  12. Quasiparticle random phase approximation uncertainties and their correlations in the analysis of 0{nu}{beta}{beta} decay

    SciTech Connect

    Faessler, Amand; Rodin, V.; Fogli, G. L.; Rotunno, A. M.; Lisi, E.; Simkovic, F.

    2009-03-01

    The variances and covariances associated to the nuclear matrix elements of neutrinoless double beta decay (0{nu}{beta}{beta}) are estimated within the quasiparticle random phase approximation. It is shown that correlated nuclear matrix elements uncertainties play an important role in the comparison of 0{nu}{beta}{beta} decay rates for different nuclei, and that they are degenerate with the uncertainty in the reconstructed Majorana neutrino mass.

  13. Active and sterile neutrino mass effects on beta decay spectra

    SciTech Connect

    Boillos, Juan Manuel; Moya de Guerra, Elvira

    2013-06-10

    We study the spectra of the emitted charged leptons in charge current weak nuclear processes to analyze the effect of neutrino masses. Standard active neutrinos are studied here, with masses of the order of 1 eV or lower, as well as sterile neutrinos with masses of a few keV. The latter are warm dark matter (WDM) candidates hypothetically produced or captured as small mixtures with the active neutrinos. We compute differential decay or capture rates spectra in weak charged processes of different nuclei ({sup 3}H, {sup 187}Re, {sup 107}Pd, {sup 163}Ho, etc) using different masses of both active and sterile neutrinos and different values of the mixing parameter.

  14. {beta}-Decay probing the electron bulk correlations

    SciTech Connect

    Kondratyev, V.N.; Ayik, S.

    1994-12-31

    The theoretical approach based on the Boltzman-Langevin model is applied to study the thermal properties of the excitation phenomena in condensed matter. This approach making use of the advantages of the thermodynamic Green`s function method provides a tool for the self-consistent description of the many-body correlations. It is demonstrated that such a correlation modifies significantly the excitation strength properties of the electron gas. The resonant thermal effects in electron bulk excitation accompanying a radioactive decay in solids are discussed.

  15. CP violation in beta decay and electric dipole moments

    NASA Astrophysics Data System (ADS)

    Ng, John; Tulin, Sean

    2012-02-01

    The T-odd correlation coefficient D in nuclear β decay probes CP violation in many theories beyond the standard model. We provide an analysis for how large D can be in light of constraints from electric dipole moment (EDM) searches. We argue that the neutron EDM dn currently provides the strongest constraint on D, which is 10-103 times stronger than current direct limits on D (depending on the model). In particular, contributions to D in leptoquark models (previously regarded as “EDM safe”) are more constrained than previously thought. Bounds on D can be weakened only by fine-tuned cancellations or if theoretical uncertainties are larger than estimated in dn. We also study implications for D from mercury and deuteron EDMs.

  16. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    SciTech Connect

    Marrs, R

    2002-11-13

    In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many more satellites in orbit, and it is important to understand their vulnerability to radiation belt pumping from nuclear explosions at high altitude or in space. This report presents the results of a calculation of the contribution of neutron beta decay to artificial belt pumping. For most high altitude nuclear explosions, neutrons are expected to make a smaller contribution than fission products to the total trapped electron inventory, and their contribution is usually neglected. However, the neutron contribution may dominate in cases where the fission product contribution is suppressed due to the altitude or geomagnetic latitude of the nuclear explosion, and for regions of the radiation belts with field lines far from the detonation point. In any case, an accurate model of belt pumping from high altitude nuclear explosions, and a self-consistent explanation of the 1962 data, require inclusion of the neutron contribution. One recent analysis of satellite measurements of electron flux from the 1962 tests found that a better fit to the data is obtained if the neutron contribution to the trapped electron inventory was larger than that of the fission products [l]. Belt pumping from high altitude nuclear explosions is a complicated process. Fission fragments are dispersed as part of the ionized bomb debris, which is constrained and guided by the earth's magnetic field. Those fission products that beta decay before being lost to the earth's atmosphere can contribute trapped energetic electrons to the earth's radiation belts. There has been a large effort to develop computer models for the contribution of

  17. Background constrains of the SuperNEMO experiment for neutrinoless double beta-decay searches

    NASA Astrophysics Data System (ADS)

    Povinec, Pavel P.

    2017-02-01

    The SuperNEMO experiment is a new generation of experiments dedicated to the search for neutrinoless double beta-decay, which if observed, would confirm the existence of physics beyond the Standard Model. It is based on the tracking and calorimetry techniques, which allow the reconstruction of the final state topology, including timing and kinematics of the double beta-decay transition events, offering a powerful tool for background rejection. While the basic detection strategy of the SuperNEMO detector remains the same as of the NEMO-3 detector, a number of improvements were accomplished for each of detector main components. Upgrades of the detector technologies and development of low-level counting techniques ensure radiopurity control of construction parts of the SuperNEMO detector. A reference material made of glass pellets has been developed to assure quality management and quality control of radiopurity measurements. The first module of the SuperNEMO detector (Demonstrator) is currently under construction in the Modane underground laboratory. No background event is expected in the neutrinoless double beta-decay region in 2.5 years of its operation using 7 kg of 82Se. The half-life sensitivity of the Demonstrator is expected to be >6.5·1024 y, corresponding to an effective Majorana neutrino mass sensitivity of |0.2-0.4| eV (90% C.L.). The full SuperNEMO experiment comprising of 20 modules with 100 kg of 82Se source should reach an effective Majorana neutrino mass sensitivity of |0.04-0.1| eV, and a half-life limit 1·1026 y.

  18. Combining and comparing neutrinoless double beta decay experiments using different nuclei

    NASA Astrophysics Data System (ADS)

    Bergström, Johannes

    2013-02-01

    We perform a global fit of the most relevant neutrinoless double beta decay experiments within the standard model with massive Majorana neutrinos. Using Bayesian inference makes it possible to take into account the theoretical uncertainties on the nuclear matrix elements in a fully consistent way. First, we analyze the data used to claim the observation of neutrinoless double beta decay in 76Ge, and find strong evidence (according to Jeffrey's scale) for a peak in the spectrum and moderate evidence for that the peak is actually close to the energy expected for the neutrinoless decay. We also find a significantly larger statistical error than the original analysis, which we include in the comparison with other data. Then, we statistically test the consistency between this claim with that of recent measurements using 136Xe. We find that the two data sets are about 40 to 80 times more probable under the assumption that they are inconsistent, depending on the nuclear matrix element uncertainties and the prior on the smallest neutrino mass. Hence, there is moderate to strong evidence of incompatibility, and for equal prior probabilities the posterior probability of compatibility is between 1.3% and 2.5%. If one, despite such evidence for incompatibility, combines the two data sets, we find that the total evidence of neutrinoless double beta decay is negligible. If one ignores the claim, there is weak evidence against the existence of the decay. We also perform approximate frequentist tests of compatibility for fixed ratios of the nuclear matrix elements, as well as of the no signal hypothesis. Generalization to other sets of experiments as well as other mechanisms mediating the decay is possible.

  19. Status and future of nuclear matrix elements for neutrinoless double-beta decay: a review

    NASA Astrophysics Data System (ADS)

    Engel, Jonathan; Menéndez, Javier

    2017-04-01

    The nuclear matrix elements that govern the rate of neutrinoless double beta decay must be accurately calculated if experiments are to reach their full potential. Theorists have been working on the problem for a long time but have recently stepped up their efforts as ton-scale experiments have begun to look feasible. Here we review past and recent work on the matrix elements in a wide variety of nuclear models and discuss work that will be done in the near future. Ab initio nuclear-structure theory, which is developing rapidly, holds out hope of more accurate matrix elements with quantifiable error bars.

  20. Experiments on the origin of molecular chirality by parity non-conservation during beta-decay

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.

    1974-01-01

    Experiments are described to test a theory for the origin of optical activity wherein the longitudinally polarized electrons resulting from parity violation during radioactive beta-decay, and their resulting circularly polarized bremsstrahlung, might interact asymmetrically with organic matter to yield optically active products. The historical background to this subject is briefly reviewed. Our experiments involve subjecting a number of racemic and optically active amino acid samples to a beta-radiation source for a period of 1.34 years (total dose: 411 Mrads), then examining them for any asymmetric effects by means of optical rotatory dispersion and analytical gas chromatography.

  1. IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments

    NASA Astrophysics Data System (ADS)

    Aalseth, C. E.; Avignone, F. T.; Brodzinski, R. L.; Cebrian, S.; Garcia, E.; Gonzalez, D.; Hensley, W. K.; Irastorza, I. G.; Kirpichnikov, I. V.; Klimenko, A. A.; Miley, H. S.; Morales, A.; Morales, J.; de Solorzano, A. Ortiz; Osetrov, S. B.; Pogosov, V. S.; Puimedon, J.; Reeves, J. H.; Sarsa, M. L.; Smolnikov, A. A.; Starostin, A. S.; Tamanyan, A. G.; Vasenko, A. A.; Vasiliev, S. I.; Villar, J. A.

    2002-05-01

    The International Germanium Experiment (IGEX) has analyzed 117 mol yr of 76Ge data from its isotopically enriched (86% 76Ge) germanium detectors. Applying pulse-shape discrimination to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of 76Ge is T1/2(0ν)>1.57×1025 yr (90% C.L.). This corresponds to an upper bound in the Majorana neutrino mass parameter, , between 0.33 and 1.35 eV, depending on the choice of theoretical nuclear matrix elements used in the analysis.

  2. 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.

  3. 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.

  4. 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.

  5. Measurement of the asymmetry parameter for sup 29 P. beta. decay

    SciTech Connect

    Masson, G.S.; Quin, P.A. )

    1990-09-01

    The asymmetry parameter for the ground state, mirror decay of polarized {sup 29}P has been measured. The {sup 29}P were produced with the {sup 28}Si({rvec d},{ital p}) reaction, and the sample polarization was determined from a simultaneous measurement of the asymmetry for the pure Gamow-Teller transition to the first excited state in {sup 29}Si at 1.27 MeV. The result, {ital A}{sub g.s.}=0.681{plus minus}0.086, is in good agreement with the {ital V}{minus}{ital A} theory of nuclear {beta} decay.

  6. Experiments on the origin of molecular chirality by parity non-conservation during beta-decay

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.

    1974-01-01

    Experiments are described to test a theory for the origin of optical activity wherein the longitudinally polarized electrons resulting from parity violation during radioactive beta-decay, and their resulting circularly polarized bremsstrahlung, might interact asymmetrically with organic matter to yield optically active products. The historical background to this subject is briefly reviewed. Our experiments involve subjecting a number of racemic and optically active amino acid samples to a beta-radiation source for a period of 1.34 years (total dose: 411 Mrads), then examining them for any asymmetric effects by means of optical rotatory dispersion and analytical gas chromatography.

  7. Shell-model calculations of beta-decay rates for s- and r-process nucleosyntheses

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Mathews, G. J.; Bloom, S. D.

    1985-10-01

    Examples of large-basis shell-model calculations of Gamow-Teller (BETA)-decay properties of specific interest in the astrophysical s- and r- processes are presented. Numerical results are given for: (1) the GT-matrix elements for the excited state decays of the unstable s-process nucleus Tc-99; and (2) the GT-strength function for the neutron-rich nucleus Cd-130, which lies on the r-process path. The results are discussed in conjunction with the astrophysics problems.

  8. Limit on. nu. sub e mass from observation of the. beta. decay of molecular tritium

    SciTech Connect

    Robertson, R.G.H.; Bowles, T.J.; Stephenson, G.J. Jr.; Wark, D.L.; Wilkerson, J.F. ); Knapp, D.A. )

    1991-08-19

    We report the most sensitive direct upper limit set on the mass {ital m}{sub {nu}} of the electron antineutrino. Our measurements of the shape of the {beta} decay spectrum of free molecular tritium yield, under the assumption of no new physics other than that of mass, a central value for {ital m}{sub {nu}}{sup 2} of {minus}147{plus minus}68{plus minus}41 eV{sup 2}, which corresponds to an upper limit of 9.3 eV (95% confidence level) on {ital m}{sub {nu}}. The result is in clear disagreement with a reported value of 26(5) eV.

  9. 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.

  10. Status and future of nuclear matrix elements for neutrinoless double-beta decay: a review.

    PubMed

    Engel, Jonathan; Menéndez, Javier

    2017-04-01

    The nuclear matrix elements that govern the rate of neutrinoless double beta decay must be accurately calculated if experiments are to reach their full potential. Theorists have been working on the problem for a long time but have recently stepped up their efforts as ton-scale experiments have begun to look feasible. Here we review past and recent work on the matrix elements in a wide variety of nuclear models and discuss work that will be done in the near future. Ab initio nuclear-structure theory, which is developing rapidly, holds out hope of more accurate matrix elements with quantifiable error bars.

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

    DOE PAGES

    Moggi, N.; Artusa, D. R.; F. T. Avignone; ...

    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.

  12. AXEL : Neutrinoless double beta decay search with a high pressure xenon gas Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Ban, Sei; AXEL collaboration

    2017-09-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. It is operated at the proportional scintillation mode. We have developed 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 to reduce background. The project is in a R&D phase, and we report the current status of our prototype chamber with 10 L and 4 bar Xe gas.

  13. A novel approach for measuring the beta-neutrino angular correlation in nuclear beta decay

    NASA Astrophysics Data System (ADS)

    Beck, M.; Ames, F.; Beck, D.; Delauré, B.; Deutsch, J.; Bollen, G.; Forstner, O.; Phalet, T.; Quint, W.; Schmidt, P.; Schuurmans, P.; Severijns, N.; Vereecke, B.; Versyck, S.

    2000-12-01

    The experiment described here will search for deviations from the V-A structure of the standard electroweak model. It is based on measuring the recoil energy spectrum in nuclear beta decay which is determined by the electron-neutrino angular correlation. For pure Fermi decays this is exactly known in the standard model and any deviation will point to additional scalar interaction. The experiment consists of a Penning trap coupled to a retardation spectrometer to measure the energy of the recoiling daughter nuclei. The current status will be presented.

  14. 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

  15. {beta} decay of the 21/2{sup +} isomer in {sup 93}Mo and level structure of {sup 93}Nb

    SciTech Connect

    Hori, T.; Masue, T.; Odahara, A.; Kura, K.; Tajiri, K.; Shimoda, T.; Fukuchi, T.; Suzuki, T.; Wakabayashi, Y.; Gono, Y.; Ogawa, K.

    2009-09-15

    The {gamma} rays associated with {beta} decay of the 21/2{sup +} isomer in {sup 93}Mo (E{sub x}=2.425 MeV, T{sub 1/2}=6.85 h) were measured with a selective sensitivity to long-lived isomer decays. A new 1262-keV transition was found in the {gamma}-{gamma} coincidence measurement, and it was attributed to a transition in {sup 93}Nb, which is the daughter nucleus of the {beta} decay of the {sup 93}Mo isomer, from the 2.753- to the 1.491-MeV levels. Accurate {gamma}-ray intensity balances have determined the {beta}-decay intensity from the {sup 93}Mo isomer to the 2.753-MeV level in {sup 93}Nb and placed no appreciable intensity for the previously reported {beta}-decay branching to the 2.180-MeV level, for which a recent in-beam {gamma}-ray experiment assigned to be I{sup {pi}} = 17/2{sup -}. Based on the {gamma}-ray intensities from the 2.753-MeV level, spin-parity assignment of this level was revised from 21/2{sup +} to 19/2{sup +}. The observed {beta}-decay intensity and the spin-parity assignment were explained by the jj-coupling shell model calculations.

  16. 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.

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

    DOE PAGES

    Xu, W.; Abgrall, N.; Avignone, F. T.; ...

    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

  18. Cryogenic detectors for dark matter search and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Münster, Andrea; Schönert, Stefan; Willers, Michael

    2017-02-01

    The search for the neutrinoless double beta decay and the direct search for dark matter particles are amongst the most fundamental questions in astroparticle physics and cosmology. To achieve a high sensitivity, detectors with an excellent energy resolution and highly efficient particle identification capabilities are required. In recent years, cryogenic particle detectors have become one of the driving technologies in these fields. Future direct dark matter search experiments aim to improve the sensitivity for low mass dark matter particles (≲ 10 GeV /c2) down to the neutrino floor and the next generation of neutrinoless double beta decay experiments aims to improve the sensitivity on the half-life to ∼1026 -1027 years, corresponding to the parameter space predicted for the inverted mass ordering and degenerate mass range. To achieve these goals, significant improvements in detector performance and in radiopurity are required and both classes of experiments can benefit from the strong synergies in the fields of detector development and in the production of high purity single-crystals.

  19. The {beta}-Decay Properties of Scissors Mode 1{sup +} States in {sup 164}Er

    SciTech Connect

    Yildirim, Z.; Kuliev, A.; Ozkan, S.; Guliyev, E.

    2008-11-11

    The beta decay properties of collective I{sup {pi}}K = 1{sup +}1 states in doubly even deformed {sup 164}Er nuclei are investigated in the framework of the rotational invariant random-phase approximation. It is shown that an essential decrease of the rate of the allowed {beta}-decay to the excited 1{sup +}-states as compared with that to the ground state may be due to the orbital nature of the states. The model Hamiltonian includes restoring rotational invariance of the deformed single particle Hamiltonian forces and the spin-spin interactions. The analytical expressions for the Gamov-Teller (G-T) and Fermi (F) decay matrix elements are derived. The single-particle energies were obtained from the Warsaw deformed Woods-Saxon potential with deformation parameter {delta}{sub 2} = 0.24. The numerical results for {beta}{sup +} transition from {sup 164}Tm to {sup 164}Er indicate the importance of using rotational invariant Hamiltonian to explain experimental data.

  20. 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.

  1. Extracting Majorana properties from strong bounds on neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Ge, Shao-Feng; Lindner, Manfred

    2017-02-01

    Assuming that neutrinos are Majorana particles, we explore what information can be inferred from future strong limits (i.e. nonobservation) for neutrinoless double beta decay. Specifically we consider the case where the mass hierarchy is normal and the different contributions to the effective mass ⟨m ⟩e e partly cancel. We discuss how this fixes the two Majorana C P phases simultaneously from the Majorana triangle and how it limits the lightest neutrino mass m1 within a narrow window. The two Majorana C P phases are in this case even better determined than in the usual case for larger ⟨m ⟩ee. We show that the uncertainty in these predictions can be significantly reduced by the complementary measurement of reactor neutrino experiments, especially the medium baseline version JUNO/RENO-50. We also estimate the necessary precision on ⟨m ⟩ee to infer nontrivial Majorana C P phases and the upper limit ⟨m ⟩ee≲1 meV sets a target for the design of future neutrinoless double beta decay experiments.

  2. The Current Status of Precision Superallowed Fermi {beta}-Decay Measurements at TRIUMF-ISAC

    SciTech Connect

    Leach, K. G.

    2011-06-28

    Recent experimental work at the TRIUMF-ISAC radioactive ion-beam facility in Vancouver Canada, has produced several new results related to precise experimental tests of fundamental symmetries. The nature of these programs range from campaigns using existing setups, to the development of new apparats to further the experimental reach. One of the primary goals has been the investigation of superallowed Fermi {beta}-decay, and its relation to Standard Model tests of CVC and CKM unitarity The extraction of experimental {beta}-decay ft values requires the measurement of three quantities: the half-life, the superallowed branching ratio, and the parent-daughter mass difference. TRIUMF-ISAC has the ability to measure each of these values with very high precision, using a gas-proportional-counter, the 8{pi}{gamma}-ray spectrometer, and TITAN, respectively. This report focuses on the recent experimental progress of the superallowed program, as well as highlighting some results from the successful halo-nucleus mass-measurement program at TITAN.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Failure of the gross theory of beta decay in neutron deficient nuclei

    SciTech Connect

    Firestone, R. B.; Schwengner, R.; Zuber, K.

    2015-05-28

    The neutron deficient isotopes 117-121Xe, 117-124Cs, and 122-124Ba were produced by a beam of 28Si from the LBNL SuperHILAC on a target of natMo. The isotopes were mass separated and their beta decay schemes were measured with a Total Absorption Spectrometer (TAS). The beta strengths derived from these data decreased dramatically to levels above ≈1 MeV for the even-even decays; 3–4 MeV for even-Z, odd-N decays; 4–5 MeV for the odd-Z, even-N decays; and 7–8 MeV for the odd-Z, odd-N decays. The decreasing strength to higher excitation energies in the daughters contradicts the predictions of the Gross Theory of Beta Decay. The integrated beta strengths are instead found to be consistent with shell model predictions where the single-particle beta strengths are divided amoung many low-lying levels. The experimental beta strengths determined here have been used calculate the half-lives of 143 neutron deficient nuclei with Z=51–64 to a precision of 20% with respect to the measured values.

  8. Constraining Majorana CP phase in the precision era of cosmology and the double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Minakata, Hisakazu; Nunokawa, Hiroshi; Quiroga, Alexander A.

    2015-03-01

    We show that precision measurement of (1) the sum of neutrino masses by cosmological observation and (2) the lifetime of neutrinoless double beta decay in ton-scale experiments, with supplementary use of (3) effective mass measured in a single beta decay experiment, would allow us to obtain information on the Majorana phase of neutrinos. To quantify the sensitivity to the phase, we use the CP exclusion fraction, a fraction of the CP phase parameter space that can be excluded for a given set of assumed input parameters, a global measure for CP violation. We illustrate the sensitivity under varying assumptions, from modest to optimistic ones, on experimental errors and theoretical uncertainty of nuclear matrix elements. Assuming that the latter can be reduced to a factor of {˜eq }1.5, we find that one of the two Majorana phases (denoted as α _{21}) can be constrained by excluding {˜eq }10-40{%} of the phase space at the 2σ confidence level even with a modest choice of experimental error for the lowest neutrino mass of 0.1 eV. The characteristic features of the sensitivity to α _{21}, such as dependences on the true values of α _{21}, are addressed.

  9. The Physics of Ultracold Neutrons and Fierz Interference in Beta Decay

    NASA Astrophysics Data System (ADS)

    Hickerson, Kevin Peter

    In the first component of this thesis, we investigate the physics of ultacold neutrons (UCN). UCN are neutrons so cold they can be stored inside of material, magnetic and gravitational bottles. Using this property we use UCN nonimaging optics to design a type of reflector that directs UCN upward in to vertical paths. Next we examine UCN passing through thin, multilayered foils. In the remaining sections we investigate the so-called Fierz interference term of free neutron beta decay, denoted bn. It is theorized that contributions to scalar and tensor interactions from physics beyond the Standard Model could be detectable in the spectrum of neutron beta decay, manifest as a nonzero value for bn. We investigate three techniques for measuring bn. The first is to use the primordial helium abundance fraction and compare that to predictive Big Bang nucleosynthesis calculations. Second we extract bn from the spectral shape generated by the 2010 data set of the UCNA experiment. Third, we discuss progress toward constructing the UCNb experimental prototype. We present the design of this new experiment that uses the UCN source at LANSCE for measuring bn, in which UCN are guided into a shielded 4π calorimeter where they are stored and decay. From Big Bang nucleosynthesis we can place the limit 0.021 < bn < 0.277 (90% C.L.) on the neutron Fierz term and from the UCNA 2010 data we set -0.044 < bn < 0.218 (90% C.L.).

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

    DOE PAGES

    Alfonso, K.; Artusa, D.  R.; F. T. Avignone; ...

    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, T0more » $$_1$$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.« less

  11. {beta} decay of the even-even {sup 124}Ba nucleus: A test for the interacting boson-fermion-fermion model

    SciTech Connect

    Brant, S.; Yoshida, N.; Zuffi, L.

    2006-08-15

    The interacting boson-fermion-fermion model approach to {beta} decay is applied to the decay from the even-even {sup 124}Ba to the odd-odd {sup 124}Cs nucleus. The theoretical results for energy levels, electromagnetic properties and {beta} decay rates are compared with experimental data for {sup 124}Cs. The calculated {beta}-decay rates demonstrate that the interacting boson approximation can be applied in the description of {beta} decays from even-even to odd-odd nuclei.

  12. Gaseous time projection chambers for rare event detection: results from the T-REX project. I. Double beta decay

    SciTech Connect

    Irastorza, I.G.; Aznar, F.; Castel, J. E-mail: faznar@unizar.es [Grupo de Física Nuclear y Astropartículas, Departamento de Física Teórica, Universidad de Zaragoza, C and others

    2016-01-01

    As part of the T-REX project, a number of R and 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 {sup 136}Xe 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 @ Q{sub ββ}. 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

  13. 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

  14. Realistic fission models, new beta-decay half-lives and the r-process in neutron star mergers

    SciTech Connect

    Shibagaki, S.; Kajino, T.; Chiba, S.; Lorusso, G.; Nishimura, S.; Mathews, G. J.

    2014-05-02

    Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission on abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process.

  15. 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.

  16. Precise absolute gamma-ray and beta(-)-decay branching intensities in the decay of Cu-67(29)

    SciTech Connect

    Chen, J.; Kondev, F. G.; Ahmad, I.; Carpenter, M. P.; Greene, J. P.; Janssens, R. V. F.; Zhu, S.; Ehst, D.; Makarashvili, V.; Rotsch, D.; Smith, N. A.

    2015-10-28

    Absolute gamma-ray emission probabilities in the beta(-)decay of Cu-67 weremeasured by means of gamma-ray and beta(-)-decay singles and beta(-)-gamma coincidences. The new results, together with the known decay scheme of Cu-67, were used to determine absolute beta(-)-decay branching intensities. The present data differ significantly from previously published values. In addition, the half-life of the I-pi = 1/2(-) isomer in Zn-67 was measured as T-1/2 = 9.37( 4) mu s, in a good agreement with earlier measurements. From the analysis of the Fermi-Kurie plots, Q(beta-)(g.s.) = 560.3( 10) keV was deduced, which differs from the previously measured value of 577( 8) keV but is in good agreement with Q(beta-)(g.s.) = 561.3(15) keV recommended in the latest Atomic Mass Evaluation.

  17. Observation of Two-Neutrino Double-Beta Decay in Xe136 with the EXO-200 Detector

    NASA Astrophysics Data System (ADS)

    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.; Danilov, M. V.; Davis, C. G.; Davis, J.; Devoe, R.; Djurcic, Z.; Dobi, A.; Dolgolenko, A. G.; Dolinski, M. J.; Donato, K.; Dunford, M.; Fairbank, W., Jr.; Farine, J.; Fierlinger, P.; Franco, D.; Freytag, D.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Green, M. P.; Hägemann, C.; Hall, C.; Hall, K.; Haller, G.; Hargrove, C.; Herbst, R.; Herrin, S.; Hodgson, J.; Hughes, M.; Johnson, A.; Karelin, A.; Kaufman, L. J.; Koffas, T.; Kuchenkov, A.; Kumar, A.; Kumar, K. S.; Leonard, D. S.; Leonard, F.; Leport, F.; Mackay, D.; MacLellan, R.; Marino, M.; Martin, Y.; Mong, B.; Montero Díez, M.; Morgan, P.; Müller, A. R.; Neilson, R.; Nelson, R.; Odian, A.; O'Sullivan, K.; Ouellet, C.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rivas, A.; Rollin, E.; Rowson, P. C.; Russell, J. J.; Sabourov, A.; Sinclair, D.; Skarpaas, K.; Slutsky, S.; Stekhanov, V.; Strickland, V.; Swift, M.; Tosi, D.; Twelker, K.; Vogel, P.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; Waite, A.; Waldman, S.; Walton, T.; Wamba, K.; Weber, M.; Wichoski, U.; Wodin, J.; Wright, J. D.; Yang, L.; Yen, Y.-R.; Zeldovich, O. Ya.

    2011-11-01

    We report the observation of two-neutrino double-beta decay in Xe136 with T1/2=2.11±0.04(stat)±0.21(syst)×1021yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for Xe136. 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.

  18. Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector.

    PubMed

    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; Danilov, M V; Davis, C G; Davis, J; deVoe, R; Djurcic, Z; Dobi, A; Dolgolenko, A G; Dolinski, M J; Donato, K; Dunford, M; Fairbank, W; Farine, J; Fierlinger, P; Franco, D; Freytag, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Green, M P; Hägemann, C; Hall, C; Hall, K; Haller, G; Hargrove, C; Herbst, R; Herrin, S; Hodgson, J; Hughes, M; Johnson, A; Karelin, A; Kaufman, L J; Koffas, T; Kuchenkov, A; Kumar, A; Kumar, K S; Leonard, D S; Leonard, F; LePort, F; Mackay, D; MacLellan, R; Marino, M; Martin, Y; Mong, B; Díez, M Montero; Morgan, P; Müller, A R; Neilson, R; Nelson, R; Odian, A; O'Sullivan, K; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rivas, A; Rollin, E; Rowson, P C; Russell, J J; Sabourov, A; Sinclair, D; Skarpaas, K; Slutsky, S; Stekhanov, V; Strickland, V; Swift, M; Tosi, D; Twelker, K; Vogel, P; Vuilleumier, J-L; Vuilleumier, J-M; Waite, A; Waldman, S; Walton, T; Wamba, K; Weber, M; Wichoski, U; Wodin, J; Wright, J D; Yang, L; Yen, Y-R; Zeldovich, O Ya

    2011-11-18

    We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (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.

  19. Production and {beta} Decay of rp-Process Nuclei {sup 96}Cd, {sup 98}In, and {sup 100}Sn

    SciTech Connect

    Bazin, D.; Baumann, T.; Ginter, T.; Hausmann, M.; Minamisono, K.; Pereira, J.; Portillo, M.; Stolz, A.; Montes, F.; Matos, M.; Perdikakis, G.; Schatz, H.; Smith, K.; Becerril, A.; Lorusso, G.; Amthor, A.; Estrade, A.; Gade, A.; Crawford, H.; Mantica, P.

    2008-12-19

    The {beta}-decay properties of the N=Z nuclei {sup 96}Cd, {sup 98}In, and {sup 100}Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory by fragmenting a 120 MeV/nucleon {sup 112}Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10-30. The half-life of {sup 96}Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp process, is 1.03{sub -0.21}{sup +0.24} s. The implications of the experimental T{sub 1/2} value of {sup 96}Cd on the abundances predicted by rp process calculations and the origin of A=96 isobars such as {sup 96}Ru are explored.

  20. Analysis of the {sup 6}He {beta} decay into the {alpha}+d continuum within a three-body model

    SciTech Connect

    Tursunov, E.M.; Baye, D.; Descouvemont, P.

    2006-01-15

    The {beta}-decay process of the {sup 6}He halo nucleus into the {alpha}+d continuum is studied in a three-body model. The {sup 6}He nucleus is described as an {alpha}+n+n system in hyperspherical coordinates on a Lagrange mesh. The convergence of the Gamow-Teller matrix element requires the knowledge of wave functions up to about 30 fm and of hypermomentum components up to K=24. The shape and absolute values of the transition probability per time and energy units of a recent experiment can be reproduced very well with an appropriate {alpha}+d potential. A total transition probability of 1.6x10{sup -6} s{sup -1} is obtained in agreement with that experiment. Halo effects are shown to be very important because of a strong cancellation between the internal and halo components of the matrix element, as observed in previous studies. The forbidden bound state in the {alpha}+d potential is found essential to reproduce the order of magnitude of the data. Comments are made on R-matrix fits.

  1. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of 21Na with improved laser trapping techniques

    SciTech Connect

    Rowe, Mary Anderson

    1999-05-01

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive 21Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88 in. cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of 21Na to the experiment. Efficient manipulation of the 21Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of 21Na. She measured the 3S1/2(F=1,m=0)-3S1/2(F=2,m=0) atomic level splitting of 21Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.

  2. {beta} decay of {sup 11}Li into {sup 9}Li and a deuteron within a three-body model

    SciTech Connect

    Baye, D.; Tursunov, E. M.; Descouvemont, P.

    2006-12-15

    The {beta}-decay process of the {sup 11}Li halo nucleus into {sup 9}Li and d is studied in a three-body model. The {sup 11}Li nucleus is described as a {sup 9}Li+n+n system in hyperspherical coordinates on a Lagrange mesh. Various {sup 9}Li+d potentials involving a forbidden state, a physical bound state, and a resonance near 0.25 MeV in the s wave are compared. With an added surface absorption, they are compatible with elastic scattering data. The transition probability per time unit is quite sensitive to the location of the resonance. For a fixed resonance location, it does not depend much on the potential choice at variance with the {sup 6}He delayed deuteron decay. The calculated transition probability per time unit is larger than the experimental value but the difference can be explained by a slightly higher resonance location and/or by absorption from the {sup 9}Li+d final channel.

  3. Beta-Decay Spectroscopy of Neutron-Rich Isotopes Utilizing a Planar Ge Double-Sided Strip Detector

    NASA Astrophysics Data System (ADS)

    Larson, N.; Liddick, S. N.; Prokop, C. J.; Kondev, F. G.; Kumar, S.; Crider, B. P.; Paulauskas, S. V.; Suchyta, S.

    2015-10-01

    In nuclear science, rapid changes in the structure of the atomic nucleus have been inferred with small changes in the neutron and proton numbers. These changes are manifested in variations of the low-energy level schemes of exotic isotopes. One region of the nuclear chart where rapid changes in deformation have been suggested based on the behavior of the first excited 2 + states is in neutron-rich nuclei near A = 110. Beta-decay spectroscopy is a sensitive and selective technique that can be used to investigate the low-energy level schemes exotic nuclei at low production rates. At the National Superconducting Cyclotron Laboratory (NSCL), a recently commissioned planar Ge double-sided strip detector (GeDSSD) is used in a novel application for these studies. Preliminary results from the decay of Tc isotopes in an experiment aimed at nuclei near A = 110 will be presented. This work was supported by the DOE NNSA DE-NA0000979 and the NSF Grant PHY1102511.

  4. Beta Decay of the Proton-Rich Nuclei 102Sn and 104Sn

    SciTech Connect

    Karny, M.; Batist, L.; Banu, A.; Becker, F.; Blazhev, A.; Brown, B. A.; Bruchle, W.; Doring, J.; Faestermann, T.; Gorska, M.; Grawe, H.; Janas, Z.; Jungclaus, A.; Kavatsyuk, M.; Kavatsyuk, O.; Kirchner, R.; La Commara, M.; Mandal, S.; Mazzocchi, C.; Miernik, K.; Mukha, I.; Muralithar, S.; Plettner, C.; Plochocki, A.; Roeckl, E.; Romoli, M.; Rykaczewski, Krzysztof Piotr; Schadel, M.; Schmidt, K.; Schwengner, R.; Zylicz, J.

    2006-01-01

    The {beta} decays of {sup 102}Sn and {sup 104}Sn were studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). For {sup 104}Sn, with three new {beta}-delayed {gamma}-rays identified, the total Gamow-Teller strength (BGT) value of 2.7(3) was obtained. For {sup 102}Sn, the {gamma}-{gamma} coincidence data were collected for the first time, allowing us to considerably extend the decay scheme. This scheme was used to unfold the TAS data and to deduce a BGT value of 4.2(8) for this decay. This result is compared to shell model predictions, yielding a hindrance factor of 3.6(7) in agreement with those obtained previously for {sup 98}Cd and {sup 100}In. Together with the latter two, {sup 102}Sn completes the triplet of Z {le} 50, N {ge} 50 nuclei with two proton holes, one proton hole and one neutron particle, and two neutron particles with respect to the doubly magic {sup 100}Sn core.

  5. Double beta decays into excited states in 110Pd and 102Pd

    NASA Astrophysics Data System (ADS)

    Lehnert, B.; Andreotti, E.; Degering, D.; Hult, M.; Laubenstein, M.; Wester, T.; Zuber, K.

    2016-11-01

    A search for double beta decays of {}110{Pd} and {}102{Pd} into excited states of the daughter nuclides has been performed using three ultra-low background gamma-spectrometry measurements in the Felsenkeller laboratory, Germany, the HADES laboratory, Belgium and at the LNGS, Italy. The combined Bayesian analysis of the three measurements sets improved half-life limits for the 2νββ and 0νββ decay modes of the {2}1+, {0}1+ and {2}2+ transitions in {}110{Pd} to 2.9\\cdot {10}20 yr, 4.0\\cdot {10}20 yr and 3.0\\cdot {10}20 yr, respectively, and in {}102{Pd} to 7.6\\cdot {10}18 yr, 8.8\\cdot {10}18 yr and 1.4\\cdot {10}19 yr, respectively, with 90% credibility.

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

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.

    2011-12-01

    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 0νββ-decay in three different nuclei, e.g. 76Ge, 100Mo and 130Te, 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.

  7. A Measurement of the Electron-Antineutrino Correlation in Free Neutron Beta Decay

    NASA Astrophysics Data System (ADS)

    Komives, Alexander; aCORN Collaboration

    2016-09-01

    The aCORN Collaboration has analyzed data taken on the NG-6 beamline at the NIST (National Institute of Standards and Technology) Center for Neutron Research and achieved the most precise measurement to date of the angular correlation (a-coefficient) between the electron and antineutrino emitted in free neutron beta decay. Such a measurement provides a test of the Electroweak Standard Model and, with the neutron lifetime, a determination of the weak vector and axial vector coupling constants that does not require a precise determination of the neutron polarization. aCORN employs a novel asymmetry method that leads to smaller systematic uncertainties compared to previous experiments that obtained the a-coefficient from the shape of the recoil proton energy spectrum. A brief description of the aCORN method, apparatus, result, and systematic effects will be presented. This work supported by NSF, NIST and DOE.

  8. 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.

  9. The DCBA/MTD Experiments for Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Iwase, H.; Kakuno, H.; Ishihara, N.; Kawai, M.; Kondou, Y.; Makida, Y.; Iwai, G.; Ohama, T.; Takahashi, K.; Yamada, Y.; Inagaki, T.; Kato, Y.; Tanaka, K.; Tonooka, M.; Kitamura, S.; Sumiyoshi, T.; Tajima, T.; Ishizuka, T.; Ito, R.; Tamura, N.; Nakano, I.; Nagasaka, Y.; Sakamoto, Y.; Teramoto, Y.

    Both experiments Drift Chamber Beta-ray Analyzer and Magnetic Tracking Detector (DCBA/MTD) aim at searches for neutrinoless double beta decay (0νββ) in several nuclei. If 0νββ would be observed, Majorana nature of neutrino would be confirmed. This means that the See-saw mechanism would be supported and Leptogenesis would be hopeful in early universe. And also the half-life measurement of 0νββ would determine the absolute mass scale of neutrinos. DCBA can obtain four-momentum of each beta-ray so that not only the energy of two beta-rays each, but also the angular correlations are measured directly. Since the method has a large number of new experimental techniques, DCBA has been placed as an R&D experiment for a future large scale experiment MTD. This paper describes the present status of DCBA and the design of MTD.

  10. Magnetic tracking detector DCBA/MTD for neutrinoless double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Ishihara, Nobuhiro; DCBA Collaboration

    2012-07-01

    Magnetic tracking detector is being developed at KEK for neutrinoless double beta decay experiments. Drift Chamber Beta-ray Analyzer (DCBA) is an R&D program to confirm the detection principle of the magnetic tracking detector. A prototype called DCBA-T2 has been constructed and operated to investigate its energy resolution and operation problems. Another new prototype DCBA-T3 is now under construction to improve the energy resolution and the amount of decay source. On the basis on DCBA-T2&T3, we have designed a future project temporarily called Magnetic Tracking Detector (MTD). One module of MTD will be able to accommodate a lot of decay source, so that several ten modules will give us a chance to investigate the effective neutrino mass down to 30 meV.

  11. Early results from the Battelle-Carolina /sup 76/Ge double-beta-decay project

    SciTech Connect

    Brodzinski, R.L.; Avignone, F.T.; Brown, D.P.; Evans, J.C.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1982-10-01

    A search for no-neutrino double beta decay of /sup 76/Ge using an anticoincidence shielded Ge spectrometer is reported. A new lower limit of T/sub 1/2/ greater than or equal to 1.7 x 10/sup 22/ y at a 90% CL was determined using a maximum likelihood analysis on a 5 keV wide energy bin centered at 2041 keV. Combining this result with the shell model calculations of Haxton, Stephenson and Strottman, we obtain average m/sub nu/ less than or equal to 10 eV and parallel eta parallel less than or equal to 2.4 x 10/sup -5/.

  12. Early results from the Battelle-Carolina /sup 76/Ge double beta decay project

    SciTech Connect

    Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1983-01-01

    A search for no-neutrino double beta decay of /sup 76/Ge using an anticoincidence shielded Ge spectrometer is reported. A new lower limit of T/sub 1/2/ greater than or equal to 1.7 x 10/sup 22/ y at a 90% CL was determined using a maximum likelihood analysis on a 5 keV wide energy bin centered at 2041 keV. Combining this result with the shell model calculations of Haxton, Stephenson and Strottman, we obtain anti m/sub nu/ less than or equal to 10 eV and absolute value eta less than or equal to 2.4 x 10/sup -5/.

  13. 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.

  14. Experimental evidence for beta-decay as a source of chirality by enantiomer analysis

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.

    1984-01-01

    Earlier experiments testing the Vester-Ulbricht beta-decay hypothesis for the origin of molecular chirality are reviewed, followed by descriptions of experiments involving attempted asymmetric radiolysis of DL-amino acids using quantitative gas chromotography as a probe for optical activity. The radiation sources included Sr-90-Y-90, C-14, and P-32 Bremsstrahlen, longitudinally polarized electrons from a linear accelerator and longitudinally polarized protons from a cyclotron. With the possible exception of the linear accelerator irradiations, these experiments failed to produce g.c.-detectable enantiomeric excesses, even at 50-70 percent gross radiolysis. Thus no unambiguous support for the Vester-Ulbricht hypothesis is found in any of the attempted asymmetric radiolyses performed to date. Radioracemization, a possible reason for these failures, is discussed.

  15. AXEL-a high pressure xenon gas TPC for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Nakamura, Kiseki; Ichikawa, Atsuko K.; Nakaya, Tsuyoshi; Minamino, Akihiro; Ban, Sei; Yanagita, Saori; Tanaka, Shunsuke; Hirose, Masanori; Sekiya, Hiroyuki; Ueshima, Kota; Miuchi, Kentaro

    2017-02-01

    To search for neutrinoless double beta decay, we have started developing a high pressure xenon gas time projection chamber as the AXEL (A Xenon ElectroLuminescence detector) project since 2014. We proposed a new scheme to measure energy deposit using electroluminescence lights to achieve high energy resolution, large mass and strong background rejection power. Important performances of compositions of our new readout scheme are shown: electric field simulation, VUV sensitivity of MPPC in high pressure gaseous xenon, response of MPPC for large amount of photons. To demonstrate as a whole system, we constructed a small prototype detector using 64 MPPCs filled with 4 bar xenon gas. Result of measurement with a 57Co gamma-ray source are shown.

  16. Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass

    SciTech Connect

    Dorofeev, O.F.; Lobanov, A.E.

    2005-06-01

    Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'.

  17. Tritium beta decay, neutrino mass matrices, and interactions beyond the standard model

    NASA Astrophysics Data System (ADS)

    Stephenson, G. J., Jr.; Goldman, T.; McKellar, B. H. J.

    2000-11-01

    The interference of charge changing interactions, weaker than the V-A standard model (SM) interaction and having a different Lorentz structure, with that SM interaction, can, in principle, produce effects near the end point of the tritium beta decay spectrum which are of a different character from those produced by the purely kinematic effect of neutrino mass expected in the simplest extension of the SM. We show that the existence of more than one mass eigenstate can lead to interference effects at the end point that are stronger than those occurring over the entire spectrum. We discuss these effects both for the special case of Dirac neutrinos and the more general case of Majorana neutrinos and show that, for the present precision of the experiments, one formula should suffice to express the interference effects in all cases. Implications for ``sterile'' neutrinos are noted.

  18. On the origin of biological chirality via natural beta-decay

    NASA Technical Reports Server (NTRS)

    Noyes, H. P.; Bonner, W. A.; Tomlin, J. A.

    1977-01-01

    An hypothesis to account for the chirality (handedness) of some biological molecules is given. Experimental evidence suggests that longitudinally polarized electrons having the chirality of terrestrial beta-decay electrons remove dextro-leucine from a racemic mixture. If, by a similar mechanism, the terrestrial environment provided more levo- than dextro-amino acids, that would account for the chirality now observed in organic molecules. An isotope of potassium has been proposed as the natural beta-emitter responsible for biomolecular chirality; however, Carbon 14 may be an even more plausible candidate. Ready availability of the carbon isotope in the terrestrial environment of 4.5 aeons ago, and the role of leucine in protein synthesis indicate that these two agents may have been chief factors in the evolution of biomolecular chirality. Suggestions for further research in this area are made.

  19. Experimental evidence for beta-decay as a source of chirality by enantiomer analysis.

    PubMed

    Bonner, W A

    1984-01-01

    Earlier experiments testing the Vester-Ulbricht beta-decay hypothesis for the origin of molecular chirality are reviewed, followed by descriptions of our own experiments involving attempted asymmetric radiolysis of DL-amino acids using quantitative gas chromotography as a probe for optical activity. Our radiation sources included 90Sr-90Y, 14C and 32P Bremsstrahlen, longitudinally polarized electrons from a linear accelerator and longitudinally polarized protons from a cyclotron. With the possible exception of the linear accelerator irradiations, these experiments failed to produce g.c.-detectable enantiomeric excesses, even at 50-70% gross radiolysis. We thus find no unambiguous support for the Vester-Ulbricht hypothesis in any of the attempted asymmetric radiolyses performed to date. Radioracemization, a possible reason for these failures, is discussed.

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

    SciTech Connect

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

    2013-08-08

    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.

  1. Precise half-life values for two-neutrino double-beta decay

    SciTech Connect

    Barabash, A. S.

    2010-03-15

    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 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, {sup 130}Te, and {sup 130}Ba are proposed. Given the measured half-life values, nuclear matrix elements were calculated. I recommend the use of these results as the most currently reliable values for the half-lives and nuclear matrix elements.

  2. On the origin of biological chirality via natural beta-decay

    NASA Technical Reports Server (NTRS)

    Noyes, H. P.; Bonner, W. A.; Tomlin, J. A.

    1977-01-01

    An hypothesis to account for the chirality (handedness) of some biological molecules is given. Experimental evidence suggests that longitudinally polarized electrons having the chirality of terrestrial beta-decay electrons remove dextro-leucine from a racemic mixture. If, by a similar mechanism, the terrestrial environment provided more levo- than dextro-amino acids, that would account for the chirality now observed in organic molecules. An isotope of potassium has been proposed as the natural beta-emitter responsible for biomolecular chirality; however, Carbon 14 may be an even more plausible candidate. Ready availability of the carbon isotope in the terrestrial environment of 4.5 aeons ago, and the role of leucine in protein synthesis indicate that these two agents may have been chief factors in the evolution of biomolecular chirality. Suggestions for further research in this area are made.

  3. 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.

  4. Pions in nuclei and manifestations of supersymmetry in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Faessler, Amand; Kovalenko, Sergey; Šimkovic, Fedor

    1998-12-01

    We examine the pion realization of the short-ranged supersymmetric (SUSY) mechanism of neutrinoless double beta decay (0νββ decay). It originates from the R-parity violating quark-lepton interactions of the SUSY extensions of the standard model of the electroweak interactions. We argue that pions are dominant SUSY mediators in 0νββ decay. The corresponding nuclear matrix elements for potentially 0νββ-decaying isotopes are calculated within the proton-neutron renormalized quasiparticle random-phase approximation (pn-RQRPA). We define those isotopes which are most sensitive to the SUSY signal and provide an outlook on the present experimental situation with the 0νββ-decay searches for SUSY. Upper limits on the R-parity violating first-generation Yukawa coupling λ'111 are derived from various 0νββ experiments.

  5. Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments

    SciTech Connect

    Sisti, M.; 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.; Moggi, N.; Morganti, S.; Napolitano, T.; Nastasi, M.; 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.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; 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.

    2016-05-31

    CUORE is a 741 kg array of TeO2 bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/(keV·kg·y) will be reached, in five years of data taking CUORE will have a 1σ half life sensitivity of 1026y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.

  6. Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments

    DOE PAGES

    Sisti, M.; Artusa, D. R.; Avignone, F. T.; ...

    2016-05-31

    CUORE is a 741 kg array of TeO2 bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/(keV·kg·y) will be reached, in five years of data taking CUORE will have a 1σ half life sensitivity of 1026y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The statusmore » and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.« less

  7. 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.

  8. Mass and beta decay of the N = Z isotope {sup 68}Se

    SciTech Connect

    Blumenthal, D.J.; Davids, C.N.; Lister, C.J.

    1995-08-01

    An experiment to measure the mass and beta decay of the N = Z nuclide {sup 68}Se was performed. The properties of {sup 68}Se are important for determining the abundance of proton-rich nuclei such as {sup 60}Ni and {sup 64}Zn, which are thought to be formed in the alpha-rich freezeout stage of a giant star. The abundances of the even-even N = Z nuclei such as {sup 60}Zn, {sup 64}Ge, and {sup 68}Se depend on the competition between ({alpha},{gamma}) and ({gamma},{alpha}) reactions, whose rates depend sensitively on the reaction Q-values. In addition, the half-life of {sup 68}Se is important in determining the path of the explosive rp-process, since reactions such as (p,{gamma}) must compete with beta decay in order to push the rp path to heavier nuclei. Using the moving tape collector system and the {sup 12}C({sup 58}Ni,2n){sup 68}Se reaction at 200 MeV, recoils were mass-selected by a slit at the FMA focal plane and implanted into the tape. After a 50-second collection period, the accumulated activity was moved to the counting position between two Ge gamma-ray detectors or a plastic scintillator beta detector and a Ge detector. The half-life of {sup 68}Se was determined to be 37 {plus_minus} 5 s, in agreement with other measurements. Gamma-gamma and beta-gamma coincidence data are under analysis, to produce the decay scheme and the electron capture decay energy.

  9. 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.

  10. 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.

  11. MOON for a next-generation neutrino-less double-beta decay experiment; present status and perspective

    NASA Astrophysics Data System (ADS)

    Shima, T.; Doe, P. J.; Ejiri, H.; Elliot, S. R.; Engel, J.; Finger, M.; Finger, M., Jr.; Fushimi, K.; Gehman, V. M.; Greenfield, M. B.; Hazama, R.; Imaseki, H.; Kavitov, P.; Kekelidze, V. D.; Kitamura, H.; Matsuoka, K.; Nakamura, H.; Nomachi, M.; Para, A.; Robertson, R. G. H.; Slunecka, M.; Shirkov, G. D.; Sissakian, A. N.; Titov, A. I.; Uchihori, Y.; Umehara, S.; Vaturin, V.; Voronov, V. V.; Wilkerson, J. F.; Will, D. I.; Yasuda, K.; Yoshida, S.

    2008-07-01

    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.

  12. 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.

  13. (Beta)-decay experiments and the unitarity of the CKM matrix

    SciTech Connect

    Garrett, P E

    2005-12-01

    The goal of this project was to perform very precise measurements of super-allowed Fermi {beta} decay in order to investigate a possible non-unitarity in the CKM matrix of the Standard Model of particle physics. Current data from 9 precisely measured {beta} decays indicated that the sum-of-squares of the first row of the CKM matrix differs from 1.0 at the 2.2{sigma} (or 98% confidence) level. If true, it would be the first firm indication of physics beyond the Standard Model--the model that has been the backbone of the worldwide physics community for more than 30 years. The physics goal of the project was to test and constrain the calculated correction factors that must be applied to the experimental data by performing measurements at the TRIUMF radioactive ion beam facility ISAC. Accurate and precise (precision goal >99.9%) half lives and decay branching ratios were measured for nuclei where different sets of calculated corrections give divergent results thereby allowing us to determine which theory, if any, gives the correct result. The LLNL contribution was to design and build the data acquisition system that will enable the experiments, and to provide theoretical calculations necessary for the interpretation of the results. The first planned measurement was {sup 34}Ar, to be followed by {sup 62}Ga and {sup 74}Rb. However, there were major problems in creating a suitable, intense beam of radioactive {sup 34}Ar. The collaboration decided to proceed with measurements on {sup 62}Ga and {sup 18}Ne. These experiments were performed in a series of measurements in the summer and fall of 2004. The LLNL team also is leading the effort to perform measurements on {sup 66}As and {sup 70}Br that are expected during 2006-2008. While the definitive experiments to meet the goals of the LDRD were not conducted during the funding period, the involvement in the radioactive program at TRIUMF has lead to a number of new initiatives, and has attracted new staff to LLNL. This LDRD has

  14. Shell-model calculations of isovector electromagnetic transitions and Gamow-Teller beta decays in the N~=28 region

    NASA Astrophysics Data System (ADS)

    Yokoyama, Atsushi; Horie, Hisashi

    1988-08-01

    Isovector E2 and M1 transitions from isobaric analog states of the N=29 isotones to low-lying states in the N=28 isotones are discussed by making use of the shell model. The fn-17/2j and the fn7/2+fn-17/2j configurations are assumed for the N=29 and N=28 isotones, respectively, where j denotes one of the p3/2, p1/2, and f5/2 orbits. First, the model space is restricted to j=p3/2 only, and it is extended to include all the p3/2, p1/2, and f5/2 orbits, in order to study stepwise the role of the various wave function components. For the isovector E2 transitions, it is confirmed that the major components of the wave functions play a decisive role for the allowed transitions in the single-particle shell model and the use of the good isospin wave functions is indispensable for the forbidden ones. For the isovector M1 transitions, it is shown that the spin-nonflip f7/2-->f7/2 transition, which is introduced by the neutron-excited components in the wave functions of the N=28 isotones, plays a very significant role: It gives rise to the important cancellation which is responsible for the strong suppression of the M1 transition strength in comparison with the simple shell-model prediction, and it becomes the leading term in the l- and j-forbidden M1 transitions. Similar discussion holds for the Gamow-Teller beta decays between the levels of the N=28 and N=29 nuclei.

  15. 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.

  16. 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.

  17. A Solution to Inductive Power Coupling in a Time-Cycled Atom Trap for Beta Decay

    NASA Astrophysics Data System (ADS)

    Lawrence, Liam; Behr, John; Anholm, Melissa; McNeil, James

    2016-09-01

    The TRINAT group at TRIUMF uses lasers and magnetic fields to confine, cool, and polarize a cloud of beta-decaying neutral alkali atoms to test weak force asymmetry. To alternate between trapping and polarizing the atoms, the trapping magnetic field must be switched on and off. This time-changing magnetic field, created by a pair of co-axial coils, produces eddy currents-and consequentially resistive heating-in nearby conductors. This heating may cause undesirable effects, including damage to the delicate pellicle mirrors which are to be used in future experiments. Previously, the current waveform in the coils consisted of two periods of a sinusoid during the on time of the trapping field (this reduces leftover field from eddy currents during the polarization time). We have calculated the relative power coupled to the pellicle mirror mount for various waveforms, and determined that using half a period of a lower-frequency sinusoid couples an order of magnitude less power than the original waveform, and approximately 2 times less than a trapezoidal wave. We measured the lifetime of the trap subject to this new waveform and found it is possible to achieve a lifetime comparable to that of a continuous trap, our best result differing by less than 5 percent.

  18. 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.

  19. 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.

  20. 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.

  1. Experiments on the origin of molecular chirality by parity non-conservation during beta-decay

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.

    1973-01-01

    Experiments are described to test a theory for the origin of optical activity wherein the longitudinally polarized electrons resulting from parity violation during radioactive beta decay, and their resulting circularly polarized Bremsstrahlung, might interact asymmetrically with organic matter to yield optically active products. Experiments involve subjecting a number of racemic and optically active amino acid samples to irradiation in a 61700 Ci90SR-90Y beta radiation source for a period of 1.34 years, then examining them for any asymmetric effects by means of optical rotatory dispersion and analytical gas chromatography. In the cases of D,L-leucine, norleucine, norvaline and proline as solids, of D,L-leucine in solution and of D,L-tyrosine in alkaline solution no optical rotation was observed during CRD measurements in the 250-630 nm spectral region. While slight differences were noted in the percent radiolysis of solid D- (12.7%) and L-leucine (16.2%) as determined by GC, no enrichment of either enantiomer was found.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Online Data Quality and Bad Interval Detection for the CUORE Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Welliver, Bradford; Cuore Collaboration

    2016-09-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a large neutrinoless double beta decay (0 νββ) search being installed underground at the Laboratori Nazionali del Gran Sasso (LNGS). 0 νββ searches can address fundamental questions about the nature of the neutrino, such as whether it is a Dirac or MAJORANA fermion, its mass scale, and may provide insight into the observed matter-antimatter asymmetry in the universe. CUORE is the largest array of bolometer instrumented crystals in the world, nineteen times larger than the previous implementation used in CUORE-0, and contains a total of 988 TeO2 crystals with a mass of 741kg and is expected to achieve a sensitivity on the 130Te 0 νββ half-life of T1 / 2 = 9 . 5 x 1025 years (90 % C.L.) after 5 years of operation. The large number of individual crystals in CUORE presents challenges for monitoring data quality and the determination of bad intervals of time in detector operation. We will discuss the work being performed to provide expanded online detector quality monitoring tools as well as the development of automated algorithms to test and identify periods of abnormal behavior across all of the individual detectors.

  7. 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.

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

    DOE PAGES

    Artusa, D. R.; Azzolini, O.; Balata, M.; ...

    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

  10. Precision long-term measurements of beta-decay-rate ratios in a controlled environment

    NASA Astrophysics Data System (ADS)

    Bergeson, S. D.; Peatross, J.; Ware, M. J.

    2017-04-01

    We report on measurements of relative beta-decay rates of Na-22, Cl-36, Co-60, Sr-90, Cs-137 monitored for more than one year. The radioactive samples are mounted in an automated sample changer that sequentially positions the five samples in turn, with high spatial precision, in front of each of four Geiger-Müller tubes. The sample wheel, detectors, and associated electronics are housed inside a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The statistical uncertainty in the count rate approaches a few times 0.01% with two weeks of averaging. Other sources of error are on a similar scale. The data are analyzed in variety of ways, comparing count rates of the various samples on one or more detectors, and comparing count rates of a particular sample across multiple detectors. We observe no statistically significant variations in the ratios of decay rates, either annual or at higher-frequency, at a level above 0.01%.

  11. Measurement of the asymmetry parameter in the {beta}-decay of {sup 35}Ar

    SciTech Connect

    Converse, A.; Haeberli, W.; Miller, M.

    1992-12-01

    The authors measured the asymmetry parameter, A{sub o}, for the beta decay of {sup 35}Ar to test the CVC hypothesis. Theory predicts A{sub o} =0.420{plus_minus}0.007 for the ground state decay of {sup 35}Ar. While early measurements disagree with this prediction (A{sub o}=0.22{plus_minus}0.03), a recent experiment gave A{sub o}= 0.49{plus_minus}0.10. The polarized sample was produced by {sup 35}Cl(p,n){sup 35}Ar, with the polarization deduced from the asymmetry in the decay to the first excited state of {sup 35}Cl. Excited state decays were identified by coincidences between {beta}`s and {gamma}`s observed in Ge detectors. The present experiment used a pure Cl{sub 2} target, higher beam current (80 nA vs. 5nA), and higher beam polarization (70% vs. 50%). Preliminary analysis of the data yields the value A{sub o} = 0.42{plus_minus}0.03. The error is dominated by the statistical uncertainty.

  12. Failure of the gross theory of beta decay in neutron deficient nuclei

    DOE PAGES

    Firestone, R. B.; Schwengner, R.; Zuber, K.

    2015-05-28

    The neutron deficient isotopes 117-121Xe, 117-124Cs, and 122-124Ba were produced by a beam of 28Si from the LBNL SuperHILAC on a target of natMo. The isotopes were mass separated and their beta decay schemes were measured with a Total Absorption Spectrometer (TAS). The beta strengths derived from these data decreased dramatically to levels above ≈1 MeV for the even-even decays; 3–4 MeV for even-Z, odd-N decays; 4–5 MeV for the odd-Z, even-N decays; and 7–8 MeV for the odd-Z, odd-N decays. The decreasing strength to higher excitation energies in the daughters contradicts the predictions of the Gross Theory of Betamore » Decay. The integrated beta strengths are instead found to be consistent with shell model predictions where the single-particle beta strengths are divided amoung many low-lying levels. The experimental beta strengths determined here have been used calculate the half-lives of 143 neutron deficient nuclei with Z=51–64 to a precision of 20% with respect to the measured values.« less

  13. 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.

  14. A neutrino mass-mixing sum rule from SO(10) and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Buccella, F.; Chianese, M.; Mangano, G.; Miele, G.; Morisi, S.; Santorelli, P.

    2017-04-01

    Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter < m ee >, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained ( m lightest ≳ 7 .5 × 10 -4 eV, at 3 σ level).

  15. The MAJORANA DEMONSTRATOR: A search for neutrinoless double-beta decay of germanium-76

    NASA Astrophysics Data System (ADS)

    Schubert, Alexis; Majorana Collaboration

    2011-04-01

    Observation of neutrinoless double-beta decay (0 νββ) could determine whether the neutrino is a Majorana particle and may provide information on neutrino mass. The MAJORANA Collaboration will search for 0 νββ of 76Ge in an array of germanium detectors enriched to 86% in 76Ge. Germanium detectors are a well-understood technology and have the benefits of excellent energy resolution, a high Q-value, and the ability to act as source and detector. The p-type point contact germanium detectors chosen by the MAJORANA Collaboration provide low noise, low energy threshold, and some ability to distinguish between the signal and background events. MAJORANA is constructing the DEMONSTRATOR, which will be used to conduct research and development toward a tonne-scale Ge experiment. The DEMONSTRATOR will be installed deep underground and will contain 40 kg of Ge deployed in an ultra-low-background shielded environment. Research supported by DOE under contracts DE-AC05-00OR22725 and DE-FG02-97ER41020.

  16. Development of liquid scintillator containing a zirconium complex for neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Fukuda, Yoshiyuki; Moriyama, Shigetaka; Ogawa, Izumi

    2013-12-01

    An organic liquid scintillator containing a zirconium complex has been developed for a new neutrinoless double beta decay experiment. In order to produce a detector that has good energy resolution (4% at 2.5 MeV) and low background (0.1 counts/(t·year)) and that can monitor tons of target isotope, we chose a zirconium β-diketone complex having high solubility (over 10 wt%) in anisole. However, the absorption peak of the diketone ligand overlaps with the luminescence of anisole. Therefore, the light yield of the liquid scintillator decreases in proportion to the concentration of the complex. To avoid this problem, we synthesized a β-keto ester complex introducing -OC3H7 or -OC2H5 substituent groups in the β-diketone ligand, which shifted the absorption peak to around 245 nm, which is shorter than the emission peak of anisole (275 nm). However, the shift of the absorption peak depends on the polarity of the scintillation solvent. Therefore we must choose a low polarity solvent for the liquid scintillator. We also synthesized a Zr-ODZ complex, which has a high quantum yield (30%) and good emission wavelength (425 nm) with a solubility 5 wt% in benzonitrile. However, the absorption peak of the Zr-ODZ complex was around 240 nm. Therefore, it is better to use the scintillation solvent which has shorter luminescence wavelength than that of the aromatic solvent.

  17. 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.

  18. The beta-decay properties in the vicinity of 78Ni

    NASA Astrophysics Data System (ADS)

    Borzov, Ivan

    2011-10-01

    The beta-decay properties of neutron-rich Cu to Ga nuclei in the vicinity of the doubly magic 78Ni have been calculated within the density-functional approach plus continuum QRPA (DF+CQRPA). The framework allows for a fully microscopic description of the Gamow-Teller (GT) and first forbidden (FF) transitions between dsgh and fpp shells. The new theoretical predictions are compared with our previous ones, with the standard FRDM calculations and recent experimental data. Of particular importance are new high quality gamma ray spectroscopy data obtained for Zn to Ga isotopes with N > 50 at Holifield Radioactive Ion Beam Facility (HRIBF). In 78Ni region, the half-lives calculated with blocking of the odd-proton on the 1pf5/2-orbital agrees with the data better than the ones with no blocking as well as the ones from standard FRDM calculations used for the r-process modeling. The high-energy first forbidden transitions in the nuclei with N > 50 populating low lying excited levels in the daughter nuclei produce a strong impact on the total half- lives and especially on the delayed neutron emission. The effect of reduction of the Pn-values compared to the pure GT- approximation in N > 50 isotopes will be discussed. This work was supported by JIHIR (ORNL, Oak Ridge).

  19. Double-beta decay in pn-QRPA model with isospin and SU(4) symmetry constraints

    NASA Astrophysics Data System (ADS)

    Krmpotić, F.; Sharma, S. Shelly

    1994-05-01

    The transition matrix elements for the 0 + → 0 + double-beta decays are calculated for 48Ca, 76Ge, 82Se, 100Mo, 128Te and 130Te nuclei, using a δ-interaction. As a guide, to fix the particle-particle interaction strengths, we exploit the fact that the missing symmetries of the mean-field approximation are restored in the random phase approximation by the residual interaction. Thus, the T = 1, S = 0 and T = 0, S = 1 coupling strengths have been estimated by invoking the partial restoration of the isospin and Wigner SU(4) symmetries, respectively. When this recipe is strictly applied, the calculation is consistent with the experimental limit for the 2ν lifetime of 48Ca and it also correctly reproduces the 2ν lifetime of 82Se. In this way, however, the two-neutrino matrix elements for the remaining nuclei are either underestimated (for 76Ge and 100Mo) or overestimated (for 128Te and 130Te) approximately by a factor of 3. With a comparatively small variation (< 10%) of the spin-triplet parameter, near the value suggested by the SU(4) symmetry, it is possible to reproduce the measured T 2ν{1}/{2} all the cases. The upper limit for the effective neutrino mass, as obtained from the theoretical estimates of 0ν matrix elements, is < m> ˜- 1 eV. The dependence of the nuclear matrix elements on the size of the configuration space has been also analyzed.

  20. 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.

  1. Precise Branching Ratios to Unbound 12C States from 12N and 12B (beta)-Decays

    SciTech Connect

    Hyldegaard, S; Forssen, C; Alcorta, M; Barker, F C; Bastin, B; Borge, M G; Boutami, R; Brandenburg, S; Buscher, J; Dendooven, P; Diget, C A; Van Duppen, P; Eronen, T; Fox, S; Fulton, B R; Fynbo, H U; Huikari, J; Huyse, M; Jeppesen, H B; Jokinen, A; Jonson, B; Jungmann, K; Kankainen, A; Kirsebom, O; Madurga, M; Moore, I; Navratil, P; Nilsson, T; Nyman, G; Onderwater, G G; Penttila, H; Perajarvi, K; Raabe, R; Riisager, K; Rinta-Antila, S; Rogachevskiy, A; Saastamoinen, A; Sohani, M; Tengblad, O; Traykov, E; Vary, J P; Wang, Y; Wilhelmsen, K; Wilschut, H W; Aysto, J

    2008-08-20

    Two complementary experimental techniques have been used to extract precise branching ratios to unbound states in {sup 12}C from {sup 12}N and {sup 12}B {beta}-decays. In the first the three {alpha}-particles emitted after {beta}-decay are measured in coincidence in separate detectors, while in the second method {sup 12}N and {sup 12}B are implanted in a detector and the summed energy of the three {alpha}-particles is measured directly. For the narrow states at 7.654 MeV (0{sup +}) and 12.71 MeV (1{sup +}) the resulting branching ratios are both smaller than previous measurements by a factor of {approx_equal} 2. The experimental results are compared to no-core shell model calculations with realistic interactions from chiral perturbation theory, and inclusion of three-nucleon forces is found to give improved agreement.

  2. Dominance of Pion Exchange in {ital {ital R}}-Parity-Violating Supersymmetric Contributions to Neutrinoless Double Beta Decay

    SciTech Connect

    Faessler, A.; Kovalenko, S.; Simkovic, F.; Schwieger, J.; Kovalenko, S.; Simkovic, F.; Simkovic, F.

    1997-01-01

    We present a new contribution of the R-parity-violating (R/{sub p}) supersymmetry (SUSY) to neutrinoless double beta decay (0{nu}{beta}{beta}) via the pion exchange between decaying neutrons. The pion coupling to the final state electrons is induced by the R/{sub p} SUSY interactions. We have found this pion-exchange mechanism to dominate over the conventional two-nucleon one. The latter corresponds to direct interaction between quarks from two decaying neutrons without any light hadronic mediator like {pi} meson. The constraints on the certain R/{sub p} SUSY parameters are extracted from the current experimental 0{nu}{beta}{beta}-decay half-life limit. These constraints are significantly stronger than those previously known or expected from the ongoing accelerator experiments. {copyright} {ital 1997} {ital The American Physical Society}

  3. Neutrinoless double-{beta} decay of deformed nuclei within quasiparticle random-phase approximation with a realistic interaction

    SciTech Connect

    Fang Dongliang; Faessler, Amand; Rodin, Vadim; Simkovic, Fedor

    2011-03-15

    In this paper a microscopic approach to calculation of the nuclear matrix element M{sup 0{nu}} for neutrinoless double-{beta} decay with an account for nuclear deformation is presented in length and applied for {sup 76}Ge, {sup 150}Nd, and {sup 160}Gd. The proton-neutron quasiparticle random-phase approximation with a realistic residual interaction (the Brueckner G matrix derived from the charge-depending Bonn nucleon-nucleon potential) is used as the underlying nuclear structure model. The effects of the short-range correlations and the quenching of the axial vector coupling constant g{sub A} are analyzed. The results suggest that neutrinoless double-{beta} decay of {sup 150}Nd, to be measured soon by the SNO+ Collaboration, may provide one of the best probes of the Majorana neutrino mass. This confirms our preliminary conclusion in Fang et al. [Phys. Rev. C 82, 051301(R) (2010)].

  4. Calibration and optimization of the Project 8 Phase II apparatus toward a tritium beta decay spectrum measurement

    NASA Astrophysics Data System (ADS)

    Guigue, Mathieu; Project 8 Collaboration

    2016-09-01

    The Project 8 collaboration aims to measure the absolute neutrino mass scale using a Cyclotron Radiation Emission Spectroscopy technique on the beta decays of tritium. With the recent developments achieved in the Phase II of the experiment such as a molecular tritium gas handling system and a larger effective decay volume, we will be able to measure the differential-energy spectrum of tritium beta decays for the very first time and be sensitive to extract the tritium endpoint value on an eV or sub-eV scale. The measured frequency of monoenergetic electrons emitted by gaseous metastable Krypton 83 atoms can be used as an energy calibration and to optimize the instrument configuration for the tritium measurement. Here we present the status of this calibration procedure and the tritium data-taking plan.

  5. Pulse Shape Analysis Techniques in Liquid Scintillator for the Identification and Suppression of Radioactive Backgrounds to Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Dunger, J.; SNO+ Collaboration

    2017-09-01

    Spatial/temporal patterns of light produced in large scintillator experiments like SNO+ are sensitive to particle ID/count. Here we set out rules for choosing a test statistic for hypothesis testing based on timing and demonstrate two applications to the SNO+ [1] neutrinoless double beta decay (0νββ) experiment: constraining internal 60Co contamination, and suppressing the 2.6 MeV γ background created by 208Tl decay on the acrylic vessel.

  6. Gamow-Teller strength distributions for {beta}{beta}-decaying nuclei within continuum quasiparticle random-phase approximation

    SciTech Connect

    Igashov, S. Yu.; Urin, M. H.; Rodin, Vadim; Faessler, Amand

    2011-04-15

    An isospin-self-consistent pn-continuum-QRPA approach is formulated and applied to describe the Gamow-Teller strength distributions for {beta}{beta}-decaying open-shell nuclei. Calculation results obtained for the pairs of nuclei {sup 76}Ge-Se, {sup 100}Mo-Ru, {sup 116}Cd-Sn, and {sup 130}Te-Xe are compared with available experimental data.

  7. 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.

  8. A search for double beta decays of 136Xe to the excited state of 136Ba with EXO-200

    NASA Astrophysics Data System (ADS)

    Yen, Yung-Ruey; EXO-200 Collaboration

    2015-10-01

    EXO-200 is one of the most sensitive searches for neutrinoless double beta decay of 136Xe in the world. The experiment uses 110 kg of active enriched liquid xenon in an ultralow background time projection chamber installed at the Waste Isolation Pilot Plant, a salt mine with a 1600 m water equivalent overburden. This detector has demonstrated excellent energy resolution and background rejection capabilities. While the experiment is designed to search for the double beta decays of 136Xe to the ground state of 136Ba, transitions to the excited states of 136Ba are also plausible. The ββ 2 ν decay to the first 0+ excited state of the daughter nuclei has been observed for 100Mo and 150Nd; this particular transition for 136Xe has a theoretical lifetime on the order of 1025 year, which is right around the sensitivity of EXO-200. We present the results from the search of double beta decays to the excited state using two years of EXO-200 data.

  9. Nuclear and particle physics aspects of the 2{nu}{beta}{beta}-decay of {sup 150}Nd

    SciTech Connect

    Dvornicky, R.; Simkovic, F.; Faessler, A.

    2007-10-12

    A discussion is given on possible realization of the Single State Dominance (SSD) hypothesis in the case of the two-neutrino double beta decay (2{nu}{beta}{beta}-decay) of {sup l50}Nd with 1{sup -} ground state of the intermediate nucleus. We conclude that the SSD hypothesis is expected to be ruled out by precision measurement of differential characteristics of this process in running NEMO 3 or planed SuperNEMO experiments unlike some unknown low-lying 1{sup +} state of {sup 150}Pm does exist. This problem can be solved via (d,{sup 2}He) charge-exchange experiment on {sup l50}Sm. Further, we address the question about possible violation of the Pauli exclusion principle for neutrinos and its consequences for the energy distributions of the 2{nu}{beta}{beta}-decay of {sup l50}Nd. This phenomenon might be a subject of interest of NEMO 3 and SuperNEMO experiments as well.

  10. Sensitivity of the NEXT-100 detector to neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    López-March, N.; NEXT Collaboration

    2017-09-01

    A high pressure xenon gas time projection chamber with electroluminescent amplification (EL HPGXe TPC) searching for the neutrinoless double beta (0νββ) decay offers: excellent energy resolution [1, 2] (0.5 ‑ 0.7% FWHM at the Qββ ), by amplifying the ionization signal with electroluminescent light, and tracking capabilities [3], as demonstrated by the NEXT collaboration using two kg-scale prototypes. The NEXT collaboration is building an EL HPGXe TPC capable of holding 100 kg (NEXT-100) of xenon isotopically enriched in 136Xe. The installation and commissioning of the NEXT-100 detector at the Laboratorio Subterráneo de Canfranc (LSC) is planned for 2018. The current estimated background level for the NEXT-100 detector is of 4 × 10‑4 counts/keV-kg-yr or less in the energy region of interest [4]. Assuming an energy resolution of 0.75% FWHM at the Qνββ and a 0νββ signal efficiency of about 28%, this gives an expected sensitivity (at 90% CL) to the 0νββ decay half life of {T}1/20ν > 6.0× {10}25 yr for an exposure of 275 kg yr. A first phase of the NEXT experiment, called NEW, is currently being commissioned at the LSC. The NEW detector is a scale 1:2 in size (1:10 in mass) of the NEXT-100 detector using the same materials and photosensors and will be used to perform a characterization of the 0νββ backgrounds and a measurement of the standard double beta decay with neutrinos (2ν ββ). An 8 sigma significance for the 2νββ signal in the NEW detector has been estimated for a 100-day run.

  11. An investigation of proton pair correlations relevant to the neutrinoless double beta decay of 76Ge

    NASA Astrophysics Data System (ADS)

    Ticehurst, David R.

    The observation of neutrinoless double beta decay (0nubetabeta ) would demonstrate that the neutrino is a Majorana particle and allow determination of its mass by comparing the measured decay rate to the calculated rate. The main uncertainty in the calculation of the 0 nubetabeta rate is due to uncertainties in the nuclear structure models used in the computation of the nuclear matrix elements for the decay process. This project tested the validity of using wavefunctions for the nuclear states involved in the 0nubetabeta process that are based on a first-order application of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In the BCS approximation, most of the strength for two-nucleon transfer reactions should be for transitions to the 0 + ground state of the final nucleus (i.e., little strength should go to the 0+ excited states). This experiment measured the strength to the first 0+ excited state for the 74Ge( 3He,n)76Se and 76Ge( 3He,n)78Se reactions relative to the strength for transition to the 0+ ground state in selenium. For both nuclei, and at 3He beam energies of 15 and 21 MeV, the observed relative strength for transfer to the first 0+ excited state was less than 13%. This result supports the validity of using the BCS approximation to describe the ground state of both 76Se and 78Se and is consistent with the results of recent ( 3He,n) cross section measurements on 74Ge and 76Ge. In addition, the magnitude and shape of the measured angular distributions suggest that contribution of the sequential two-nucleon transfer process, which is an indicator of long-range nucleon-nucleon correlations, is over-predicted by the DWBA code FRESCO.

  12. 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.

  13. On the measurement of the electron-neutrino correlation in neutron beta decay

    SciTech Connect

    Bowman, J. D.

    2004-01-01

    A new approach to the measurement of A, the electron-neutrino correlation, in neutron beta decay is presented. A precise measurement of A can lead to a precise determination of G{sub A}/G{sub V}. Coincidences between electrons and protons are detected in a field-expansion spectrometer. Both electrons and protons are detected in segmented Si detectors. The spectrometer configuration has a long, {approx} 1 meter, drift distance for the proton. The electron energy and time of flight between the electron and proton are measured. We show that by sorting the data on proton time of flight and electron energy, A can be determined with a statistical accuracy of {approx} 5.1/{radical}n, where n is the number of decays observed. The approach has a number of advantages. Thin-dead-layer segmented Si detectors are commercially available. There are no material apertures to determine the acceptance of the apparatus. The charged particles interact only with electric and magnetic fields before striking the detectors. Coincident detection of electrons and protons reduces backgrounds, and allows the in situ determination of backgrounds. In the analysis, it is not necessary to sort on the relative electron and proton direction and hence electron back scattering does not cause systematic uncertainties. A time of flight spectrum is obtained for each electron energy. Different parts of the spectra have different sensitivities to A. The parts of the spectra that are insensitive to A can be used to verify the accuracy of the electric and magnetic field determinations.

  14. Constraints on general SU(2)/sub L/ x SU(2)/sub R/ x U(1) electroweak models from nuclear beta decay

    SciTech Connect

    Herczeg, P.

    1986-01-01

    The implications of beta-decay experiments for more general versions of SU(2)/sub L/ x SU(2)/sub R/ x U(1) models are analyzed, including the most general one which allows for CP-violation, unequal left- and right-handed quark mixing angles, and mixing in the leptonic sector. For each scenario, the constraints on the pertinent parameters from beta-decay measurements are compared with the constraints provided on them by other data.

  15. Electron capture branching ratio measurements in an ion trap for double beta decay experiments at TITAN

    NASA Astrophysics Data System (ADS)

    Brunner, T.; Brodeur, M.; Champagne, C.; Frekers, D.; Krücken, R.; Lapierre, A.; Delheij, P.; Ringle, R.; Ryjkov, V.; Smith, M.; Tanihata, I.; Dilling, J.

    2008-10-01

    Double beta decay (ββ) is a nuclear decay mode expected to appear in at least two varieties, the double-neutrino (2ν) and the zero-neutrino (0ν) mode. The 0νββ-decay is of particular interest as it requires the neutrino to be a Majorana particle. The search for such a decay is presently being carried out or planned in a number of experiments, such as EXO, MAJORANA, GERDA, CUORE, COBRA, NEMO-III and SNO+. The 0ν-decay rate depends on the neutrino mass but, unfortunately, also on a rather complex nuclear matrix element, making the extraction of the mass heavily dependent on the underlying theoretical nuclear model. However, all theoretical models can readily be tested against the 2ν mode, which, unlike its 0ν counterpart, only involves simple Gamow Teller nuclear matrix elements. These elements can be determined experimentally either through charge-exchange reactions or, for the ground-state transition, through the electron capture (EC) or single β-decay of the intermediate odd odd nucleus. The present program is geared towards the measurement of the EC branching ratios (BR). In most cases, these ratios are poorly known or not known at all, because EC is usually suppressed by several orders of magnitude compared to the β-decay counterpart due to energy considerations. Traditional methods for measuring these ratios have so far suffered from overwhelming background generated by these high-energy electrons. Recently, a unique background-free method for measuring EC branching ratios was proposed using the TITAN ion trap at the TRIUMF ISAC (Isotope Separator and ACcelerator) radioactive beam facility. The measurements will make use of the EBIT (Electron Beam Ion Trap) operating in Penning mode where electrons from the β--decay will be confined by the magnetic field. K-shell X-rays from EC will be detected by seven X-ray detectors located around the trap, thus providing orders of magnitude background suppression and thus ideal low-BR measurement environment.

  16. Double-beta decay investigation with highly pure enriched [Formula: see text]Se for the LUCIFER experiment.

    PubMed

    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

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of [Formula: see text]Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched [Formula: see text]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 [Formula: see text]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 [Formula: see text]Th, [Formula: see text]U and [Formula: see text]U are respectively: [Formula: see text]61, [Formula: see text]110 and [Formula: see text]74 [Formula: see text]Bq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the [Formula: see text]Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of [Formula: see text]Se to 0[Formula: see text], 2[Formula: see text] and 2[Formula: see text] excited states of [Formula: see text]Kr of 3.4[Formula: see text]10[Formula: see text], 1.3[Formula: see text]10[Formula: see text] and 1.0[Formula: see text]10[Formula: see text] y, respectively, with a 90 % C.L.

  17. 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.

  18. Comparative tests of isospin-symmetry-breaking corrections to superallowed 0{sup +}{yields}0{sup +} nuclear {beta} decay

    SciTech Connect

    Towner, I. S.; Hardy, J. C.

    2010-12-15

    We present a test with which to evaluate the calculated isospin-symmetry-breaking corrections to superallowed 0{sup +}{yields}0{sup +} nuclear {beta} decay. The test is based on the corrected experimental Ft values being required to satisfy conservation of the vector current (CVC). When applied to six sets of published calculations, the test demonstrates quantitatively that only one set, the one based on the shell model with Saxon-Woods radial wave functions, provides satisfactory agreement with CVC. This test can easily be applied to any sets of calculated correction terms that are produced in future.

  19. Electron-capture decay of [sup 100]Tc and the double-[beta] decay of [sup 100]Mo

    SciTech Connect

    Garcia, A.; Chan, Y.; da Cruz, M.T.F.; Larimer, R.M.; Lesko, K.T.; Norman, E.B.; Stokstad, R.G.; Wietfeldt, F.E.; Zlimen, I.; Moltz, D.M.; Batchelder, J.; Ognibene, T.J. ); Hindi, M.M. )

    1993-06-01

    We have measured the electron-capture decay branch of [sup 100]Tc to be (1.8[plus minus]0.9)[times]10[sup [minus]3]%, from which we deduce log[ital ft]=4.45[sub [minus]0.30][sup +0.18]. This indicates that a two-step process connecting only the ground states of [sup 100]Mo-[sup 100]Tc-[sup 100]Ru can account for the measured 2[nu] double-[beta]-decay rate of [sup 100]Mo.

  20. {beta} decay of odd-A As to Ge isotopes in the interacting boson-fermion model

    SciTech Connect

    Brant, S.; Yoshida, N.; Zuffi, L.

    2004-11-01

    The structure of odd-mass isotopes of As and Ge is described in the framework of the proton-neutron interacting boson-fermion model. The energy levels and the electromagnetic properties of {sup 69,71,73}As and {sup 69,71,73}Ge are calculated and compared with the experiment. The {beta}-decay rates from the As isotopes to the Ge isotopes are calculated. The calculated decays tend to be stronger than the observed ones. This may indicate a mixture of components outside the model space in the wave functions of actual nuclei. The effect of the higher-order terms in the decay operators seems small.

  1. Low-energy structure of Co-66(27)39 and Co-68(27)41 populated through beta decay

    SciTech Connect

    Liddick, S. N.; Abromeit, B.; Bolla, M; Larson, N.; Suchyta, S.; Ayres, A; Bey, A.; Bingham, C. R.; Cartegni, L.; Grzywacz, R.; Madurga, M; Miller, D; Padgett, Stephen; Paulauskas, S.; Crawford, H. L.; Darby, I. G.; Rajabali, M. M.; Ilyushkin, S.; Rykaczewski, Krzysztof Piotr

    2012-01-01

    The low-energy level structures for the neutron-rich Co isotopes at N = 39 and N = 41 are constructed following the beta decay of the respective even-even Fe isotopes. Spin and parity assignments of the lowest energy populated state in {sup 66}Co and {sup 68}Co are consistent with a 1{sup +} spin and parity assignment and attributed to the coupling of the deformed proton configurations identified in {sup 67}Co and deformed neutron configurations inferred from neighboring Fe isotones. Comparisons along the N = 39 and N = 41 isotonic chains reveal a similarity in the structures of the Co and Mn isotopes.

  2. Analysis of beta-decay data acquired at the Physikalisch-Technische Bundesanstalt: Evidence of a solar influence

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Parkhomov, A.; Scargle, J. D.

    2016-11-01

    According to an article entitled Disproof of solar influence on the decay rates of 90Sr/90Y by Kossert and Nähle of the Physikalisch-Technische Bundesanstalt (PTB) [1], the PTB measurements show no evidence of variability. We show that, on the contrary, those measurements reveal strong evidence of variability, including an oscillation at 11 year-1 that is suggestive of an influence of internal solar rotation. An analysis of radon beta-decay data acquired at the Geological Survey of Israel (GSI) Laboratory for the same time interval yields strong confirmation of this oscillation.

  3. 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).

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

    NASA Astrophysics Data System (ADS)

    Kogler, Laura Katherine

    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 (2nubetabeta). 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 2nubetabeta 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 2nubetabeta half-life was measured to be T1/2 = [9.81 +/- 0.96(stat) +/- 0.49(syst)] x 1020 y.

  5. Quasiparticle random phase approximation analysis of the double beta decay of [sup 100]Mo to the ground state and excited states of [sup 100]Ru

    SciTech Connect

    Suhonen, J. ); Civitarese, O. )

    1994-06-01

    The beta decay rate of the 1[sup +] ground state of [sup 100]Tc to the ground and excited states of [sup 100]Mo and [sup 100]Ru has been calculated using a combination of the charge-conserving and charge-nonconserving modes of the quasiparticle random phase approximation theory. These results, as well as the calculated [ital E]2 decay properties of [sup 100]Mo and [sup 100]Ru, are compared with data. In addition, the two-neutrino double beta decay rates of [sup 100]Mo to the ground state and excited states of [sup 100]Ru are evaluated and analyzed using available experimental data. For completeness, the neutrinoless double beta decay rate of [sup 100]Mo is calculated and used to extract the value of the effective neutrino mass and the parameters of a general weak-interaction Hamiltonian.

  6. Study of the double beta decays of 96Ru and 104Ru.

    PubMed

    Andreotti, Erica; Hult, Mikael; Marissens, Gerd; de Orduña, Raquel González; Vermaercke, Peter

    2012-09-01

    In this work we present new improved experimental limits for the partial half-lives of the double beta processes of (96)Ru and (104)Ru, obtained by means of a γ-ray spectrometry measurement. A disc of metallic Ru of natural isotopic abundance was sandwiched between two HPGe-detectors in the 225 m deep underground laboratory HADES. After 108 days of measurement, the lower bounds for the partial half-lives were up to 6.9×10(19) yr for (96)Ru and 1.9×10(20) yr for (104)Ru.

  7. Study of the $\\beta $ Decay of Fission Products with the DTAS Detector

    SciTech Connect

    Guadilla, V.; Algora, A.; Tain, J. L.; Agramunt, J.; Aysto, J.; Briz, J. A.; Cucoanes, A.; Eronen, T.; Estienne, M.; Fallot, M.; Fraile, L. M.; Ganioglu, E.; Gelletly, W.; Gorelov, D.; Hakala, J.; Jokinen, A.; Jordan, D.; Kankainen, A.; Kolhinen, V.; Koponen, J.; Lebois, M.; Martinez, T.; Monserrate, M.; Montaner-Piza, A.; Moore, I.; Nacher, E.; Orrigo, S. E. A.; Penttila, H.; Pohjalainen, I.; Porta, A.; Reinikainen, J.; Reponen, M.; Rinta-Antila, S.; Rubio, B.; Rytkonen, K.; Shiba, T.; Sonnenschein, V.; Sonzogni, A. A.; Valencia, E.; Vedia, V.; Voss, A.; Wilson, J. N.; Zakari-Issoufou, A. -A.

    2017-01-01

    Total Absorption Spectroscopy measurements of the β decay of 103Mo and 103Tc, important contributors to the decay heat summation calculation in reactors, are reported in this work. Furthermore, the analysis of the experiment, performed at IGISOL with the new DTAS detector, show new β intensity that was not detected in previous measurements with Ge detectors.

  8. A Diffusion Cloud Chamber Study of Very Slow Mesons. II. Beta Decay of the Muon

    DOE R&D Accomplishments Database

    Lederman, L. M.; Sargent, C. P.; Rinehart, M.; Rogers, K.

    1955-03-01

    The spectrum of electrons arising from the decay of the negative mu meson has been determined. The muons are arrested in the gas of a high pressure hydrogen filled diffusion cloud chamber. The momenta of the decay electrons are determined from their curvature in a magnetic field of 7750 gauss. The spectrum of 415 electrons has been analyzed according to the theory of Michel.

  9. Background Studies of CANDLES for Double Beta Decays of 48Ca

    NASA Astrophysics Data System (ADS)

    Kakubata, Hidekazu; Candles Collaboration

    2014-09-01

    An underground observatory is the most effective to perform low background experiments because an underground environment avoids cosmic muon. Backgrounds still remain in this environment, so to grasp their origin and intensity is necessary. We perform the CANDLES experiment in the Kamioka Underground Laboratory to search for 0 νββ of 48Ca, which has the highest Q-value (4.27 MeV) of all ββ nuclides. Here we must consider backgrounds in the energy region around the Q-value. On the CANDLES detector, internal backgrounds from radial contamination in CaF2 crystal scintillators can be restrained to a level free from problems. However, other backgrounds were observed in the energy region higher than the Q-value and peak structure is found in 7 ~ 8 MeV. We inferred that γ-rays emitted by neutron capture reactions on Fe is the main origin of backgrounds. To confirm this hypothesis, we carried out special run using 252Cf neutron source set outside the detector. As a result, we found that the source of these backgrounds is γ-ray from neutron capture on the surrounding material of the detector, especially on the rock and the stainless. For further background reduction, we plan to install additional passive neutron and γ-ray shields. An underground observatory is the most effective to perform low background experiments because an underground environment avoids cosmic muon. Backgrounds still remain in this environment, so to grasp their origin and intensity is necessary. We perform the CANDLES experiment in the Kamioka Underground Laboratory to search for 0 νββ of 48Ca, which has the highest Q-value (4.27 MeV) of all ββ nuclides. Here we must consider backgrounds in the energy region around the Q-value. On the CANDLES detector, internal backgrounds from radial contamination in CaF2 crystal scintillators can be restrained to a level free from problems. However, other backgrounds were observed in the energy region higher than the Q-value and peak structure is found in 7 ~ 8 MeV. We inferred that γ-rays emitted by neutron capture reactions on Fe is the main origin of backgrounds. To confirm this hypothesis, we carried out special run using 252Cf neutron source set outside the detector. As a result, we found that the source of these backgrounds is γ-ray from neutron capture on the surrounding material of the detector, especially on the rock and the stainless. For further background reduction, we plan to install additional passive neutron and γ-ray shields. T. Kishimoto, S. Yoshida, S. Umehara, K. Nakajima, T. Iida, T. Ohata, K. Tetsuno, M. Nomachi, D. Tanaka, T. Maeda, N. Nakatani for the CANDLES Collaboration.

  10. Beta decay of very neutron-rich110Mo studied at the new IGISOL facility

    NASA Astrophysics Data System (ADS)

    Lhersonneau, G.; Honkanen, A.; Huhta, M.; Jauho, P. P.; Jokinen, A.; Leino, M.; Oinonen, M.; Ollikainen, E.; Parmonen, J. M.; Aysto, J.

    1994-06-01

    The decay of the new activity110Mo (t1/2=0.30(4).s) has been observed at the new IGISOL separator. Multiscaled singles, β-γ-t and γ- y-t coincidences were recorded. The decay scheme suggests Iπ=2+ for the ground state of the daughter nucleus110Tc. Three 1+ levels are fed with logft values below 5, indicating no drastic change among Mo and Ru decays at the middle of the neutron shell. This experiment confirms the expectation that the new IGISOL facility will allow the identification of one or two new more neutron-rich isotopes per element in this region.

  11. Study of the $$\\beta $$ Decay of Fission Products with the DTAS Detector

    DOE PAGES

    Guadilla, V.; Algora, A.; Tain, J. L.; ...

    2017-01-01

    Total Absorption Spectroscopy measurements of the β decay of 103Mo and 103Tc, important contributors to the decay heat summation calculation in reactors, are reported in this work. Furthermore, the analysis of the experiment, performed at IGISOL with the new DTAS detector, show new β intensity that was not detected in previous measurements with Ge detectors.

  12. Electron emission and recoil effects following the beta decay of He6

    NASA Astrophysics Data System (ADS)

    Schulhoff, Eva E.; Drake, G. W. F.

    2015-11-01

    Probabilities for atomic electron excitation (shake-up) and ionization (shake-off) are studied following the beta-decay process →Li+6He6+e-+ν¯e , and in particular, recoil-induced contributions to the shake-off probability are calculated within the nonrelativistic sudden approximation. A pseudostate expansion method together with Stieltjes imaging is used to represent the complete two-electron spectrum of final Li+6 ,Li26+, and Li36+ states. Results for the recoil correction show a 7 σ disagreement with the experiment of Carlson et al. [Phys. Rev. 129, 2220 (1963), 10.1103/PhysRev.129.2220]. A variety of sum rules, including a newly derived Thomas-Reich-Kuhn oscillator strength sum rule for dipole recoil terms, provides tight constraints on the accuracy of the results. Calculations are performed for the helium 1 s 2 s 3S metastable state, as well as for the 1 s21S ground state. Our results would reduce the recoil-induced correction to the measured electroneutrino coupling constant ae μ from the apparent 0.6% used in the experiments to 0.09%.

  13. 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.

  14. The LUCIFER/CUPID-0 demonstrator: searching for the neutrinoless double-beta decay with Zn82Se scintillating bolometers

    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. S.; Nastasi, M.; Nisi, S.; Nones, C.; 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.

    2017-09-01

    Future experiments on neutrinoless double beta-decay with the aim of exploring the inverted hierarchy region have to employ detectors with excellent energy resolution and zero background in the energy region of interest. Cryogenic scintillating bolometers turn out to be a suitable candidate since they offer particle discrimination: the dual channel detection of the heat and the scintillation light signal allows for particle identification. In particular such detectors permit for a suppression of α-induced backgrounds, a key-issue for next-generation tonne-scale bolometric experiments. We report on the progress and current status of the LUCIFER/CUPID-0 demonstrator, the first array of scintillating bolometers based on enriched Zn82Se crystals which is expected to start data taking in 2016 and the potential of this detection technique for a future tonne-scale bolometric experiment after CUORE.

  15. Deformed shell model results for two-neutrino positron double-{beta} decay of {sup 74}Se

    SciTech Connect

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

    2009-11-15

    Half-lives T{sub 1/2}{sup 2{nu}} for two-neutrino positron double-{beta} decay modes {beta}{sup +} EC/ECEC are calculated for {sup 74}Se, a nucleus of current experimental interest, using the deformed shell model based on Hartree-Fock states and employing a modified Kuo interaction in ({sup 2}p{sub 3/2}, {sup 1}f{sub 5/2}, {sup 2}p{sub 1/2}, {sup 1}g{sub 9/2}) space. The calculated half-life for the ECEC mode is {approx}10{sup 26}yr, and it may be possible to observe this in future experiments.

  16. New limits on the neutrino mass, lepton conservation, and no-neutrino double beta decay of /sup 76/Ge

    SciTech Connect

    Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

    1983-03-07

    A continuing search for the no-neutrino mode of the double beta decay of /sup 76/Ge has resulted in a new lower limit T/sub 1/2//sup 0nu/ > or =1.7 x 10/sup 22/ yr. This value corresponds to a 90% confidence level determined with a maximum-likelihood analysis of the energy interval 2041 +- 2 keV. Combined with recent shell-model calculations, the data imply m/sub ..nu../< or =10 eV and a limit on lepton nonconservation Vertical BaretaVertical Bar< or =2.4 x 10/sup -5/. In the context of the shell model, the data imply that the electron neutrino is not a Majorana mass eigenstate.

  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. Search for the l-forbidden beta decay /sup 207/Tl. -->. /sup 207/Pb(570 keV)

    SciTech Connect

    Hindi, M.M.; Adelberger, E.G.; Kellogg, S.E.; Murakami, T.

    1988-09-01

    We have searched for the l-forbidden beta decay of /sup 207/Tl to the first excited state of /sup 207/Pb by looking for 570-keV ..gamma.. rays following the decay of /sup 207/Tl. We find a branching ratio of (2.4 +- 5.6) x 10/sup -7/ per /sup 207/Tl decay. This limit could provide a test for calculations of core polarization, meson exchange, and ..delta.. excitation effects. We also find a branch of (0.54 +- 0.05)% for the l-forbidden M1 transition /sup 207/Pb(898,(3/2/sup -/..-->..570,(5/2/sup -/) and measure the intensities of ..gamma.. rays emitted following the decay of /sup 211/Pb.

  19. 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.

  20. 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 .

  1. TRINAT apparatus for measurements of correlations from the beta decay of magneto-optically trapped polarized alkali atoms

    NASA Astrophysics Data System (ADS)

    Gorelov, Alexandre; Behr, J. A.; Kurchaninov, L.; Olchanski, K.; Smale, S.; Behling, S.; Melconian, D.; Fenker, B.; Mehlman, M.; Shilding, P. D.; Anholm, M.; Ashery, D.; Gwinner, G.; Trinat Collaboration

    2013-10-01

    Measurements of correlations from beta decay of highly polarized atoms from MOT requires a fast transition between trapping and polarization/measurement cycles to reduce an unwanted expansion of decaying atoms. To achieve this, we have developed an apparatus employing AC MOT, which required placing high-current and low-inductance coils of magnetic quadrupole inside the stainless steel vacuum vessel and allowed us to reduce a time gap between trapping and measurement cycles (the quadrupole magnetic field in the trap region has to become less than 50 mG) to less than 100 μs. The nuclear detection system consists of an electrostatic spectrometer of recoiling ions and shake-off electrons with MCP based detectors in back-to-back geometry as well as two scintillator based β - telescopes, normal to the MCP-MCP axis. This system allowed us to successfully measure the beta asymmetry in the β+ decay of polarized 37K atoms with significantly reduced backgrounds. Time-varying magnetic field from the AC MOT and stationary guiding electric field allowed us to probe the energy distribution of the shakeoff electrons in the range 5 -30 eV. NSERC, NRC through TRIUMF, DOE ER40773 and ER41747, State of Texas, Israel Science Foundation.

  2. Scintillating bolometric technique for the neutrino-less double beta decay search: The LUCIFER/CUPID-0 experiment

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    CUPID is a proposed future tonne-scale bolometric neutrino-less double beta decay (0 νββ) experiment to probe the Majorana nature of neutrinos and discover lepton number violation in the so-called inverted hierarchy region of the neutrino mass. In order to improve the sensitivity with respect to the current bolometric experiments, the source mass must be increased and the backgrounds in the region of interest must be dramatically reduced. The background suppression can be achieved discriminating β / γ against α events by means of the different light yield produced in the interactions within a scintillating bolometer. The increase in the number of 0 νββ emitters demands for crystals grown with enriched material. LUCIFER/CUPID-0, the first demonstrator of CUPID, aims at running the first array of enriched scintillating Zn82Se bolometers (total mass of about 7 kg of 82Se) with a background level as low as 10-3 counts/(keV kg y) in the energy region of interest. We present the results of the first measurement performed on three Zn82Se enriched scintillating bolometers operated deep underground in the Hall C of the Laboratori Nazionali del Gran Sasso.

  3. 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.

  4. Spectroscopy of ^86,87,88Se levels populated through beta decay of ^86,87,88As

    NASA Astrophysics Data System (ADS)

    Pereira, J.; Walters, W. B.; Smith, M. K.; Aprahamian, A.; Chiara, C. J.; Gade, A.; Ginter, T.; Hackman, G.; Larson, N.; Liddick, S. N.; Prokop, C.; Schatz, H.; Tarasov, O. B.

    2013-04-01

    The overabundances of Sr, Y and Zr elements observed in some r-process-enriched, metal-poor stars complicate the quest for the r-process site. Jones et al. [Phys. Rev. C73, (2006)] reported an anomalously high 886-keV E(2+) in ^88Se54 , which may be related to a doubly-magic ^90Se56. This new waiting point might explain the Sr, Y, Zr overabundances. A new experiment was carried out at NSCL to measure the structure of neutron-rich Se isotopes. New spectroscopic information of ^86,87,88Se has been obtained through the beta decay of ^86,87,88As nuclei. A gamma ray at 93 keV has been observed in the decay of ^87As that could arise from the transition 5/2^+ to 3/2^+, as observed in the higher-Z N = 53 isotones. A gamma-ray transition at 651 keV has been observed in the decay of ^88As that could be a part of the yrast cascade in ^88Se. The 886 keV gamma-ray observed by Jones et al. could not be verified.

  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. PandaX-III: Searching for neutrinoless double beta decay with high pressure 136Xe gas time projection chambers

    NASA Astrophysics Data System (ADS)

    Chen, Xun; Fu, ChangBo; Galan, Javier; Giboni, Karl; Giuliani, Franco; Gu, LingHui; Han, Ke; Ji, XiangDong; Lin, Heng; Liu, JiangLai; Ni, KaiXiang; Kusano, Hiroki; Ren, XiangXiang; Wang, ShaoBo; Yang, Yong; Zhang, Dan; Zhang, Tao; Zhao, Li; Sun, XiangMing; Hu, ShouYang; Jian, SiYu; Li, XingLong; Li, XiaoMei; Liang, Hao; Zhang, HuanQiao; Zhao, MingRui; Zhou, Jing; Mao, YaJun; Qiao, Hao; Wang, SiGuang; Yuan, Ying; Wang, Meng; Khan, Amir N.; Raper, Neill; Tang, Jian; Wang, Wei; Dong, JiaNing; Feng, ChangQing; Li, Cheng; Liu, JianBei; Liu, ShuBin; Wang, XiaoLian; Zhu, DanYang; Castel, Juan F.; Cebrián, Susana; Dafni, Theopisti; Garza, Javier G.; Irastorza, Igor G.; Iguaz, Francisco J.; Luzón, Gloria; Mirallas, Hector; Aune, Stephan; Berthoumieux, Eric; Bedfer, Yann; Calvet, Denis; d'Hose, Nicole; Delbart, Alain; Diakaki, Maria; Ferrer-Ribas, Esther; Ferrero, Andrea; Kunne, Fabienne; Neyret, Damien; Papaevangelou, Thomas; Sabatié, Franck; Vanderbroucke, Maxence; Tan, AnDi; Haxton, Wick; Mei, Yuan; Kobdaj, Chinorat; Yan, Yu-Peng

    2017-06-01

    Searching for the neutrinoless double beta decay (NLDBD) is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments. PandaX-III (particle and astrophysical xenon experiment III) will search for the NLDBD of 136Xe at the China Jin Ping Underground Laboratory (CJPL). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90% 136Xe enriched gas operated at 10 bar. Fine pitch micro-pattern gas detector (Microbulk Micromegas) will be used at both ends of the TPC for the charge readout with a cathode in the middle. Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution. The detector will be immersed in a large water tank to ensure 5 m of water shielding in all directions. The second phase, a ton-scale experiment, will consist of five TPCs in the same water tank, with improved energy resolution and better control over backgrounds.

  7. 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.

  8. 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.

  9. Thick-target yields of iodine isotopes from proton interactions in Te, and the double-[beta] decays of [sup 128,130]Te

    SciTech Connect

    da Cruz, M.T.F.; Bardayan, D.W.; Chan, Y.; Garcia, A.; Hindi, M.M.; Larimer, R.; Lesko, K.T.; Norman, E.B.; Rossi, D.F.; Stokstad, R.G.; Wietfeldt, F.E.; Zlimen, I. Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 Physics Department, University of California, Berkeley, California 94720 )

    1993-12-01

    We measured thick-target yields of [sup 126,128,130]I from bombardments of natural Te targets with 15-, 30-, 45-, and 50-MeV protons, together with iodine production cross sections for 1.85- and 5.0-GeV protons. Using these data, we have estimated the relative cosmic-ray induced production of [sup 126]Xe, [sup 128]Xe, and [sup 130]Xe in Te ores. These quantities are significantly different from those used previously in a determination of the ratio of the double-[beta] decay half-lives of [sup 130]Te and [sup 128]Te, and as a result the cosmic-ray correction is smaller than previously assumed. A revised correction of cosmic-ray produced xenon can change the half-life ratio by about 6%. This quantity is of importance because it can be used to set a limit on the 0-[nu] double-[beta] decay mode.

  10. New branching ratio measurement of the pion beta - decay. pi. /sup +/. -->. pi. /sup 0/ + e/sup +/ + nu/sub e/

    SciTech Connect

    Gaille, F.C.

    1983-01-01

    A new measurement of the branching ratio R of the pion beta-decay mode ..pi../sup +/..--> pi../sup 0/ + e/sup +/ + nu/sub e/ was made at the High Energy Pion channel P/sup 3/ of the LAMPF accelerator at Los Alamos. The measurement used a completely new ''decay-in-flight technique'' which differs from all the previous experiments based on a ''decay-at-rest technique''. The two gamma rays from the decay of the neutral pion ..pi../sup 0/ were detected in coincidence using a modified version of the LAMPF ..pi../sup 0/ spectrometer. The number of analyzed pion beta-decay events (after background subtraction) was 1127.14 +/- 33.92. Great care was taken to make an accurate measurement of the absolute number of charged pions in the beam and yielded (2.1457 +/- 0.0223) X 10/sup 14/. A Monte Carlo program was then used to simulate the pion beta-decay process and the response of the apparatus to this decay. The resulting value of the pion beta-decay branching ratio R = GAMMA(..pi../sup +/..--> pi../sup 0/ + e/sup +/ + nu/sub e/)/GAMMA(..pi../sup +/..-->..all) is R/sub EXP/ = (1.021 +/- 0.039) X 10/sup -8/, whereas the current CVC theory predicts R/sub THE/ = (1.047 +/- 0.008) X 10/sup -8/. Within the uncertainties, the experimental and theoretical values agree. Thus, the newly measured value of R is consistent with the theory and CVC hypothesis.

  11. ({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.

  12. 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.

  13. The {sup 150}Nd({sup 3}He,t) and {sup 150}Sm(t,{sup 3}He) reactions with applications to {beta}{beta} decay of {sup 150}Nd

    SciTech Connect

    Guess, C. J.; Brown, B. A.; Deaven, J. M.; Hitt, G. W.; Meharchand, R.; Zegers, R. G. T.; Adachi, T.; Fujita, H.; Hatanaka, K.; Hirota, K.; Ishikawa, D.; Matsubara, H.; Okamura, H.; Ong, H. J.; Suzuki, T.; Tamii, A.; Yosoi, M.; Zenihiro, J.; Akimune, H.; Algora, A.

    2011-06-15

    The {sup 150}Nd({sup 3}He,t) reaction at 140 MeV/u and {sup 150}Sm(t,{sup 3}He) reaction at 115 MeV/u were measured, populating excited states in {sup 150}Pm. The transitions studied populate intermediate states of importance for the (neutrinoless) {beta}{beta} decay of {sup 150}Nd to {sup 150}Sm. Monopole and dipole contributions to the measured excitation-energy spectra were extracted by using multipole decomposition analyses. The experimental results were compared with theoretical calculations obtained within the framework of the quasiparticle random-phase approximation, which is one of the main methods employed for estimating the half-life of the neutrinoless {beta}{beta} decay (0{nu}{beta}{beta}) of {sup 150}Nd. The present results thus provide useful information on the neutrino responses for evaluating the 0{nu}{beta}{beta} and 2{nu}{beta}{beta} matrix elements. The 2{nu}{beta}{beta} matrix element calculated from the Gamow-Teller transitions through the lowest 1{sup +} state in the intermediate nucleus is maximally about half that deduced from the half-life measured in 2{nu}{beta}{beta} direct counting experiments, and at least several transitions through 1{sup +} intermediate states in {sup 150}Pm are required to explain the 2{nu}{beta}{beta} half-life. Because Gamow-Teller transitions in the {sup 150}Sm(t,{sup 3}He) experiment are strongly Pauli blocked, the extraction of Gamow-Teller strengths was complicated by the excitation of the 2({h_bar}/2{pi}){omega}, {Delta}L=0, {Delta}S=1 isovector spin-flip giant monopole resonance (IVSGMR). However, the near absence of Gamow-Teller transition strength made it possible to cleanly identify this resonance, and the strength observed is consistent with the full exhaustion of the non-energy-weighted sum rule for the IVSGMR.

  14. XAX: A multi-ton, multi-target detection system for dark matter, double beta decay and pp solar neutrinos

    NASA Astrophysics Data System (ADS)

    Arisaka, K.; Wang, H.; Smith, P. F.; Cline, D.; Teymourian, A.; Brown, E.; Ooi, W.; Aharoni, D.; Lam, C. W.; Lung, K.; Davies, S.; Price, M.

    2009-03-01

    A multi-target detection system XAX, comprising concentric 10 ton targets of 136Xe and 129/131Xe, together with a geometrically similar or larger target of liquid Ar, is described. Each is configured as a two-phase scintillation/ionization TPC detector, enhanced by a full 4π array of ultra-low radioactivity quartz photon intensifying detectors (QUPIDs) replacing the conventional photomultipliers for detection of scintillation light. It is shown that background levels in XAX can be reduced to the level required for dark matter particle (WIMP) mass measurement at a 10-10 pb WIMP-nucleon cross-section, with single-event sensitivity below 10-11 pb. The use of multiple target elements allows for confirmation of the A2 dependence of a coherent cross-section, and the different Xe isotopes provide information on the spin-dependence of the dark matter interaction. The event rates observed by Xe and Ar would modulate annually with opposite phases from each other for WIMP mass >˜100 GeV/c2. The large target mass of 136Xe and high degree of background reduction allow neutrinoless double beta decay to be observed with lifetimes of 1027 1028 years, corresponding to the Majorana neutrino mass range 0.01 0.1 eV, the most likely range from observed neutrino mass differences. The use of a 136Xe-depleted 129/131Xe target will also allow measurement of the pp solar neutrino spectrum to a precision of 1 2%.

  15. 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.

  16. Predictions for the Majorana CP violation phases in the neutrino mixing matrix and neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Girardi, I.; Petcov, S. T.; Titov, A. V.

    2016-10-01

    We obtain predictions for the Majorana phases α21 / 2 and α31 / 2 of the 3 × 3 unitary neutrino mixing matrix U = Ue† Uν, Ue and Uν being the 3 × 3 unitary matrices resulting from the diagonalisation of the charged lepton and neutrino Majorana mass matrices, respectively. We focus on forms of Ue and Uν permitting to express α21 / 2 and α31 / 2 in terms of the Dirac phase δ and the three neutrino mixing angles of the standard parametrisation of U, and the angles and the two Majorana-like phases ξ21 / 2 and ξ31 / 2 present, in general, in Uν. The concrete forms of Uν considered are fixed by, or associated with, symmetries (tri-bimaximal, bimaximal, etc.), so that the angles in Uν are fixed. For each of these forms and forms of Ue that allow to reproduce the measured values of the three neutrino mixing angles θ12, θ23 and θ13, we derive predictions for phase differences (α21 / 2 -ξ21 / 2), (α31 / 2 -ξ31 / 2), etc., which are completely determined by the values of the mixing angles. We show that the requirement of generalised CP invariance of the neutrino Majorana mass term implies ξ21 = 0 or π and ξ31 = 0 or π. For these values of ξ21 and ξ31 and the best fit values of θ12, θ23 and θ13, we present predictions for the effective Majorana mass in neutrinoless double beta decay for both neutrino mass spectra with normal and inverted ordering.

  17. Gamow-Teller strength in the beta decay of mirror nuclides

    NASA Astrophysics Data System (ADS)

    Honkanen, J.; ńystö, J.; Koponen, V.; Taskinen, P.; Eskola, K.; Messelt, S.; Ogawa, K.

    1987-12-01

    Distribution of the Gamow-Teller strength has been studied both experimentally and theoretically in the f7/2 shell mirror nuclides over a wide energy range. Experimental studies were performed using light ion induced reactions and the He-jet transport method or the ion-guide on-line isotope separation, IGISOL. Several transitions were observed to excited states in the decays of 43Ti and 51Fe and some in the decays of 47Cr, 49Mn, 43Co and 55Ni. Theoretical calculations were made by a shell model code using fn7/2+(P3/2, f5/2, P1/2)1 shell space. The β-feeding has been predicted for all transitions up to about 4 MeV excitation in each daughter nucleus. The quenching of the Gamow-Teller strength has been studied by comparing the experimental strength with the calculation. The formation of the giant Gamow-Teller resonance has been studied theoretically as a function of the mass number.

  18. {beta}-decay in neutron-deficient Hg, Pb, and Po isotopes

    SciTech Connect

    Moreno, O.; Sarriguren, P.; Alvarez-Rodriguez, R.; Guerra, E. Moya de

    2006-05-15

    The effect of nuclear deformation on the energy distributions of the Gamow-Teller strength is studied in neutron-deficient Hg, Pb, and Po even isotopes. The theoretical framework is based on a self-consistent deformed Skyrme Hartree-Fock mean field with pairing correlations between like nucleons in BCS approximation and residual spin-isospin interactions treated in the proton-neutron quasiparticle random-phase approximation. After a systematic study of the Gamow-Teller strength distributions in the low-excitation-energy region, relevant for {beta}{sup +} decay, we have identified the best candidates to look for deformation signatures in their {beta}{sup +}-decay patterns. {beta}{sup +} half-lives and total Gamow-Teller strengths B(GT{sup {+-}}) are analyzed as well.

  19. Improved limit on the mass of. nu. sub e from the beta decay of molecular tritium

    SciTech Connect

    Bowles, T.J.; Robertson, R.G.H.; Wark, D.L.; Wilkerson, J.F.; Stephenson, G.J.; Friar, J.L. ); Knapp, D.A. )

    1990-01-01

    We report a new upper limit of 13.4 eV (95% confidence level) on the mass of the electron antineutrino from a study of the shape of the beta spectrum of free molecular tritium. This result appears to be inconsistent with a reported value for the mass of 26(5) eV. The electron neutrino is evidently not massive enough to close the universe by itself. 21 refs., 1 fig., 2 tabs.

  20. Astrophysical(α,γ) reaction in inverse kinematics; Electron screening effect in the beta-decay

    NASA Astrophysics Data System (ADS)

    Ujić, P.; de Oliveira, F.; Lagoyannis, A.; Mertzimekis, T. J.; Harissopulos, S.; Demetriou, P.; Spyrou, A.; Stodel, C.; Saint-Laurent, M. G.; Kamalou, O.; Lefebvre-Schuhl, A.; Grevy, S.; Caceres, L.; Lewitowicz, M.; Amthor, M. A.; Perot, L.; Coc, A.; Tatischeff, V.; Kiener, J.; Sorlin, O.; Lepailleur, A.; Assié, M.; Bastin, B.; Achouri, L.; Borcea, R.; Borcea, C.; Stanoiu, M.; de France, G.; Clement, E.; Pautrat, A.; Buta, A.; Gaudefroy, L.; Meot, V.; Deloncle, I.

    2012-02-01

    The abundance calculations of the p-nuclei produced in explosive stellar sites rely on the Hauser-Feshbach (HF) theory with the alpha-article optical model potential (α-OMP) one of its major ingredients. To date, most of the (α, γ) cross sections measured show that HF calculations can be wrong by a factor of ten or more especially when phenomenological α-OMP are employed. To investigate the relevant uncertainties entering the HF calculations and furthermore develop global microscopic α-OMPs, systematic (α, γ) cross-section measurements are necessary. This led us to perform a feasibility study of (α, γ) measurements in inverse kinematics that will allow us to employ also radioactive beams in the future. Hence, the 4He(78Kr,γ)82Sr reaction was studied using the LISE3 spectrometer to separate the 82Sr recoils from the primary 78Kr beam. Although an excellent rejection factor > 1010 was achieved, the position of the ions of interest was unexpectedly masked by a secondary beam of high intensity. Given these, new setup improvements are proposed to remove the pollutant ions. Recently, many experiments were conducted in order to study the influence of the environment (especially in a metallic material) on the decay probability of radioactive nuclei. Additionally, hydrogen-like fusion reactions were performed indicating a change in the cross-section due to the influence of the Coulomb field screening induced by quasi-free electrons in metals. This was explained by the Debye screening model which treats metallic electrons within Maxwell-Boltzmann statistics. We measured the decay rate of 19O in metallic, insulating and superconducting environments whereas the electrons in the superconductors should obey the Bose-Einstein statistics. The decay rate measurement was supported by a branching ratios measurement. We found that the effect on the decay rate, if any, is less than the 0.1%, far below the theoretical predictions.

  1. Recoil effects due to electron shake-off following the beta decay of 6 He

    NASA Astrophysics Data System (ADS)

    Drake, Gordon W. F.; Schulhoff, Eva

    2016-05-01

    There are currently several experiments in progress to search for new physics beyond the Standard Model by high precision studies of angular correlations in the β decay of the helium isotope 6He to form 6Li +e- +νe. After the β decay process, the atomic electrons of 6 Li+ adjust to the sudden change of nuclear charge from 2 to 3. We calculate the probabilities for electron shake-up and shake-off, including recoil effects, by the use of a Stieltjes imaging representation of the final states. A variety of sum rules provides tight consistency checks on the accuracy of the results. Results obtained previously indicate that there is a 7 σ disagreement between theory and experiment for the additional nuclear recoil induced by the emission of atomic shake-off electrons. This disagreement will be further studied, and the results extended to the 1 s 2 p3 P and metastable 1 s 2 s3 S states as initial states of 6 He before β-decay. Research supported by the Natural Sciences and Engineering Research Council of Canada.

  2. Protocol for maximising light signal of metallic magnetic calorimeters for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Oh, S. Y.; Kim, G. B.; Kim, H. L.; Kim, I.; Kim, S. R.; Lee, H. J.; Lee, M. K.; Kim, Y. H.

    2017-08-01

    We report on a systematic study for maximising the signal size of metallic magnetic calorimeters (MMCs) used for large-area light detectors operating at milli-Kelvin temperatures. These light detectors are to be used for phonon-scintillation detection using a scintillating crystal for rare event search experiments. The light detector is composed of a 2 inch wafer as an absorber for scintillation light from a crystal, and an MMC as its sensor. A systematic calculation for the expected signal size is made with different SQUID selections, Er concentrations of an MMC sensor, dimensions of the meander-shaped pick-up coil, field currents and operating temperatures. The optimisation study finds that more than five times larger signals can be achieved compared with that of a reference condition in which 90 eV root-mean-squared threshold is obtained. We also describe the inductance measurement for several MMC devices with different size of the pick-up coil to be applied for an optimal condition. This optimisation protocol is also valid for MMC applications of x-ray, alpha and beta spectroscopies.

  3. Beta-decay spectroscopy of r-process nuclei around N = 126

    NASA Astrophysics Data System (ADS)

    Hirayama, Y.; Miyatake, H.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Jung, H. S.; Oyaizu, M.; Mukai, M.; Kimura, S.; Sonoda, T.; Wada, M.; Kim, Y. H.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

    2016-02-01

    KEK Isotope Separation System (KISS) has been developed at RIKEN to study the β-decay properties of neutron-rich isotopes with neutron numbers around N = 126 to understand the astrophysical site of r-process. These nuclei will be produced by multi-nucleon transfer reactions in neutron-rich heavy ion collisions between 136Xe beam and 198Pt target. The KISS consists of an argon gas cell combined with a laser resonance ionization technique for atomic number selection, of an ISOL mass-separation system and of a detector system for the β-decay spectroscopy of nuclei around N = 126. The argon gas cell of KISS is a key component for thermalizing (stopping and neutralizing) and accumulating the unstable nuclei, and selectively ionizing them by using laser. We have performed off-and on-line experiments to study the basic properties of the gas cell as well as KISS. We successfully extracted the laser-ionized stable 198Pt atoms from the KISS at the commissioning on-line experiments. We furthermore extracted laser-ionized unstable 199Pt atoms and confirmed that the measured half-life was in good agreement with the reported value. Now KISS is ready for lifetime measurements of Pt, Ir, and Os isotopes around N = 126.

  4. The nature of massive neutrinos and multiple mechanisms in neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Meroni, Aurora

    2015-11-01

    Determining the nature -Dirac or Majorana- of massive neutrinos is one of the most pressing and challenging problems in the field of neutrino physics. We discuss how one can possibly extract information on the couplings, if any, which might be involved in (ββ)_{0ν}-decay using a multi-isotope approach. We investigate as well the potential of combining data on the half-lives of nuclides with largely different Nuclear Matrix Elements such as 136Xe and of one or more of the four nuclei 76Ge, 82Se, 100Mo and 130Te, for discriminating between different pairs of noninterfering or interfering mechanisms of (ββ)_{0ν}-decay. The case studies do not extend to the evaluation of the theoretical uncertainties of the results, due to the nuclear matrix elements calculations and other causes.

  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. Very Low Energy Protons From the Beta Decay of Proton Rich Nuclei For Nuclear Astrophysics

    SciTech Connect

    Simmons, E.; Trache, L.; Banu, A.; McCleskey, M.; Roeder, B.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Aysto, J.; Davinson, T.; Woods, P. J.; Lotay, G. J.

    2010-03-01

    We have developed a new experimental technique to measure very low energy protons from beta-delayed p-decay of proton-rich nuclei produced and separated with the MARS recoil spectrometer at TAMU. Recently we have investigated the beta-delayed p-decays of {sup 23}Al and {sup 31}Cl and obtained information on the resonances in the reactions {sup 22}Na(p,gamma){sup 23}Mg and {sup 30}P(p,gamma){sup 31}S, respectively. These reactions are important in explosive H-burning in Novae. A simple setup consisting of a telescope made of a thin double sided Si strip detector (p-detector) backed or sandwiched between two thick Si detectors (beta-detectors) was designed. We studied two different p-detectors and found that the thinner detectors with a small cell size are best to measure proton energies as low as 2-300 keV.

  7. Beta-decay of proton-rich nucleus ^23Al and astrophysical consequences

    NASA Astrophysics Data System (ADS)

    Zhai, Y. J.; Iacob, V. E.; Al-Abdullah, T.; Fu, C.; Hardy, J. C.; Nica, N.; Park, H. I.; Tabacaru, G.; Trache, L.; Tribble, R. E.

    2006-04-01

    We will present the results of a β-decay study that was motivated by a nuclear astrophysics problem. For the first time γ-rays have been observed following the β decay of pure samples of ^23Al. We used the ^1H(^24Mg,2n)^23Al reaction and the MARS recoil separator of Texas A&M University. β and β-γ coincidence measurements were made with a fast tape-transport system and β and γ-ray detectors. The experiment allowed us to measure β branching ratios and deduce logft values for transitions to 14 final states in ^23Mg, including the isobaric analog state, and from them to determine unambigously the spin and parity of ^23Al ground state to be J^π=5/2^+. We will discuss how this excludes the large increase in the radiative proton-capture cross section for the reaction ^22Mg(p,γ)^23Al at astrophysical energies which was implied by claims that the spin and parity is J^π=1/2^+ [1,2], claims that motivated this study in the first place. The reaction is possible candidate to explain why space-based gamma-ray telescopes do not observe γ-rays from the decay of long-lived ^22Na formed in ONe novae explosions [3]: a larger cross section would be required to divert significant flux from the A=22 into the A=23 mass chain. [1] X. Z. Cai et al, Phys. Rev. C 65, 024610 (2002). [2] H.-Y. Zhang et al., Chin. Phys. Lett. 19, 1599 (2002). [3] M. Wiescher et al., Astrophys. J. 343, 352 (1989).

  8. Sensitivity of the LUX detector to the possible neutrinoless double beta decay of 134Xe

    NASA Astrophysics Data System (ADS)

    Pease, Evan; LUX Collaboration Collaboration

    2017-01-01

    The Large Underground Xenon (LUX) detector is a 370-kg liquid xenon (LXe) time-projection chamber designed primarily for the direct detection of weakly-interacting massive particles (WIMPs), a leading dark matter candidate. LUX operates on the 4850-foot level of the Sanford Underground Research Facility in Lead, SD. The unenriched xenon of LUX contains the natural 10.4% abundance of the isotope 134Xe, a candidate for the lepton-number-violating process of neutrinoless double beta (0 νββ) decay. If observed, this process would confirm the existence of massive Majorana neutrinos and would be a possible path to the measurement of neutrino mass and other studies of new weak-interaction physics. Given its xenon mass and the length of exposure for the LUX detector, there is an opportunity to improve upon the T1 / 2 > 5 . 8 ×1022 yr sensitivity of the 6.5-kg DAMA experiment (enriched to 17.1%134Xe) from 2002 (Bernabei, et al., Phys. Lett. B 527, 182-186, 2002.). Building upon previous LUX measurements of the energy resolution and signal yields up to 662 keV, this talk will go over the response of the LUX detector at 826 keV, the 134Xe Q-value, and the current status of the LUX 134Xe 0 νββ analysis.

  9. MOON for neutrino-less {beta}{beta} decays and {beta}{beta} nuclear matrix elements

    SciTech Connect

    Ejiri, H.

    2009-11-09

    The MOON project aims at spectroscopic 0v{beta}{beta} studies with the v-mass sensitivity of 100-30 meV by measuring two beta rays from {sup 100}Mo and/or {sup 82}Se. The detector is a compact super-module of multi-layer PL scintillator plates. R and D works made by the pro to-type MOON-1 and the small PL plate show the possible energy resolution of around {sigma}{approx}2.2%, as required for the mass sensitivity. Nuclear matrix elements M{sup 2v} for 2v{beta}{beta} are shown to be given by the sum {sigma}{sub L}M{sub k} of the 2v{beta}{beta} matrix elements M{sub k} through intermediate quasi-particle states in the Fermi-surface, where Mi is obtained experimentally by using the GT(J{sup {pi}} = 1{sup +}) matrix elements of M{sub i}(k) and M{sub f}(k) for the successive single-{beta} transitions through the k-th intermediate state.

  10. Beta decay of 125Sb and level structures in 125Te

    NASA Astrophysics Data System (ADS)

    Sainath, M.; Venkataramaniah, K.; Sood, P. C.

    1999-08-01

    The decay of 2.76y 125 Sb to levels of 125 Te has been studied using an HPGe de-tector for gamma-ray and a mini orange electron spectrometer for conversion electron measure-ments. We identify 38 transitions in this decay, including 13 gamma rays and 4 conversion electron lines being reported for the first time. New results also include E1 multipolarity assignments to 3 newly observed transitions and M-shell conversion coefficient for the 109 keV M4 transition. A revised 125 Te level scheme is constructed using Ritz combination principle. While confirming the existence of 10 well established levels below 700 keV excitation, we introduce 3 other levels at 402.0, 538.6 and 652.9 keV. Interpretation of the observed levels in terms of various theoretical approaches is briefly discussed. The newly introduced 538.6 keV (1/2 + ) and 652.9 keV (3/2 + ) levels are seen as the two missing members of the (s1Ä 2 + ) and (d3Ä 2 + ) sextuplet in the quasiparticle-phonon coupling scheme.

  11. Two-neutrino double-beta decay of 150Nd to excited final states

    NASA Astrophysics Data System (ADS)

    Kidd, Mary; Esterline, James; Finch, Sean; Tornow, Werner

    2013-10-01

    This study yields the first detection of the coincidence gamma rays from the 01+excited state of 150Sm. These gamma rays have energies of 333.97 keV and 406.52 keV, and are emitted in coincidence through a 01+--> 21+--> 0gs+transition. The enriched Nd2O3 sample obtained from Oak Ridge National Laboratory consists of 40.13 g 150Nd. This sample was observed for 642.8 days at the Kimballton Underground Research Facility, producing 21.6 net events in the region of interest. This count rate gives a half life of T1 / 2 = 1 .07-0.25+0.45 (stat) +/- 0 . 07 (syst .) years, which agrees within uncertainties with another recent measurement in which no coincidence was employed. Lower limits were also obtained for decays to higher excited final states. Finally, the nuclear matrix element was extracted from this half life with a value of 0.0232-0.0037+0.0032. This work was supported in part by the US Department of Energy, Office of Nuclear Physics under grant No. DE-FG02-97ER41033.

  12. Improvement of gross theory of beta-decay for application to nuclear data

    NASA Astrophysics Data System (ADS)

    Koura, Hiroyuki; Yoshida, Tadashi; Tachibana, Takahiro; Chiba, Satoshi

    2017-09-01

    A theoretical study of β decay and delayed neutron has been carried out with a global β-decay model, the gross theory. The gross theory is based on a consideration of the sum rule of the β-strength function, and gives reasonable results of β-decay rates and delayed neutron in the entire nuclear mass region. In a fissioning nucleus, neutrons are produced by β decay of neutron-rich fission fragments from actinides known as delayed neutrons. The average number of delayed neutrons is estimated based on the sum of the β-delayed neutron-emission probabilities multiplied by the cumulative fission yield for each nucleus. Such a behavior is important to manipulate nuclear reactors, and when we adopt some new high-burn-up reactors, properties of minor actinides will play an important roll in the system, but these data have not been sufficient. We re-analyze and improve the gross theory. For example, we considered the parity of neutrons and protons at the Fermi surface, and treat a suppression for the allowed transitions in the framework of the gross theory. By using the improved gross theory, underestimated half-lives in the neutron-rich indium isotopes and neighboring region increase, and consequently follow experimental trend. The ability of reproduction (and also prediction) of the β-decay rates, delayed-neutron emission probabilities is discussed. With this work, we have described the development of a programming code of the gross theory of β-decay including the improved parts. After preparation finished, this code can be released for the nuclear data community.

  13. Positron-neutrino correlation measurements in the beta decay of magneto-optically trapped potassium-38m atoms

    NASA Astrophysics Data System (ADS)

    Gorelov, Alexandre I.

    This thesis describes the measurement of the angular correlation between the positron and the neutrino emitted in the beta decay of the isomer 38mK. This is a superallowed transition between nuclear states of the same spin and parity (0+) which is known to result primarily from the vector component of the weak interaction. The angular correlation involves two parameters. In the Standard Model of the weak interaction these have the values a = 1 and b = 0. Any meaningful deviation from this result can be interpreted as evidence for the existence of a scalar component in the weak interaction. The fundamentally new method that was used involved selectively confining neutral atoms of the isomer in a magneto-optical trap located between two detectors, one to measure the energy and direction of the positron and the other to detect the 38Ar nuclei that recoil with a momentum pR = -(pe + pnu). The 38mK atoms were produced using the TRIUMF/ISAC facility. The trap provided a pure, cold, compact source essential to avoid distortion of the recoil momenta. For those events in which the positron was detected, the recoil momenta were deduced by measuring the time of flight from the trap to the recoil detector. About 500,000 positron-recoil coincident events were recorded. When the analysis, based on detailed Monte Carlo simulations, was restricted to positrons with kinetic energy > 2.5 MeV, it showed that the angular correlation could be characterized by a "reduced" correlation parameter a = 0.9988 +/- 0.0028(stat) +/- 0.0034(syst) (68% CL) where a = a/(1 + 0.1503 b). This measurement is consistent with the Standard Model and is 33% more restrictive than the only comparable previous measurement for such a transition. In the most general form, the strength of a possible scalar interaction can be specified in terms of two complex numbers, L and R, which define, respectively, the coupling to left- and right-handed neutrinos. This experiment did not usefully restrict the value of Re

  14. a Measurement of the Beta Decay Asymmetry of Neon -19 as a Test of the Standard Model

    NASA Astrophysics Data System (ADS)

    Jones, Gordon Lyman

    We have performed an accurate measurement of the parity-violating beta asymmetry of ^{19 }Ne decay. This asymmetry can be calculated in the standard electro-weak model using the measured ft value for ^{19}Ne and a value of G_{V}V_{ud }, where G_{V} is the Fermi coupling constant and V_{ud } is the u-d element of the Cabibbo-Kobayashi -Maskawa mass mixing matrix. The asymmetry is particularly sensitive to the existence of right-handed weak currents. In addition, if we assume that right-handed currents do not exist, the ^{19}Ne asymmetry and ft value provide an independent measurement of G _{V}V_{ud}.. The zero energy intercept of the asymmetry was measured to be A_0=-{0.0360} _sp{-0.0006}{+0.0008}+/-0.0003. The errors are systematic and statistical, respectively. The measured value is in good agreement with the value predicted by the standard model together with the ft values for ^{19}Ne decay and the 0^+ to 0^+ decays (A_0=-{0.0361}+/-0.0007). However, the value of V_{ud } derived from the measured asymmetry, the ^{19}Ne ft value, and mu decay violates unitarity by 1.5 sigma.. The slope of the asymmetry as a function of beta energy was measured to be {dAover dE }=(-{4.2}+/-0.7+/-0.8) times 10^{-3}/MeV. The standard model prediction for the slope is -3.5(1) times 10^{-3}/MeV. The slope is sensitive to second class currents which are not present in the standard model. The implied value of the second class form factor, d^ {II} is -60 +/- 54 +/- 60 which is consistent with the standard model value of 0. The beta asymmetry was measured from the difference in the beta emission rate parallel to and anti-parallel to the polarization of the decaying ^{19 }Ne. Polarized ^{19} Ne atoms were trapped in a thin walled cell at the center of a solenoidal magnetic field. Positrons from ^{19}Ne beta decay spiraled along the magnetic field lines and were detected in Si(Li) detectors at either end of the solenoid. The asymmetry was determined from the ratio of the rates in these two

  15. 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.

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

    DOE PAGES

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; ...

    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

  17. Limits of Majorana neutrino mass from combined analysis of data from 76Ge and 136Xe neutrinoless double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Klimenko, A. A.; Rumyantseva, N. S.

    2017-01-01

    We present effective Majorana neutrino mass limits < m ββ> obtained from the joint analysis of the recently published results of 76Ge and 136Xe neutrinoless double beta decay (0νββ) experiments, which was carried out by using the Bayesian calculations. Nuclear matrix elements (NMEs) used for the analysis are taken from the works, in which NMEs of 76Ge and 136Xe were simultaneously calculated. This reduced systematic errors connected with NME calculation techniques. The new effective Majorana neutrino mass limits < m ββ> less than [85.4-197.0] meV are much closer to the inverse neutrino mass hierarchy region.

  18. Total absorption studies of high priority decays for reactor applications: 86Br and 91Rb

    NASA Astrophysics Data System (ADS)

    Algora, A.; Rice, S.; Guadilla, V.; Tain, J. L.; Valencia, E.; Zakari-Issoufou, A.-A.; Agramunt, J.; Äystö, J.; Batist, L.; Briz, J. A.; Bowry, M.; Bui, V. M.; Caballero-Folch, R.; Cano-Ott, D.; Cucoanes, A.; Eronen, T.; Elomaa, V. V.; Estevez, E.; Estienne, M.; Fallot, M.; Farrelly, G. F.; Fraile, L. M.; Fleming, M.; Ganioglu, E.; Garcia, A. R.; Gelletly, W.; Gómez-Hornillos, B.; Gorelov, D.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, D.; Kankainen, A.; Kolhinen, V. S.; Kondev, F. G.; Koponen, J.; Lebois, M.; Martinez, T.; Mason, P.; Mendoza, E.; Monserrate, M.; Montaner-Pizá, A.; Moore, I.; Nácher, E.; Orrigo, S. E. A.; Penttilä, H.; Podolyák, Z.; Pohjalainen, I.; Porta, A.; Regan, P. H.; Reinikainen, J.; Reponen, M.; Rinta-Antila, S.; Rissanen, J.; Rubio, B.; Rytkönen, K.; Shiba, T.; Sonnenschein, V.; Sonzogni, A. A.; Sublet, J.-Ch.; Vedia, V.; Voss, A.; Wilson, J. N.

    2017-09-01

    Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the JYFLTRAP system at the IGISOL facility of the University of Jyväskylä.

  19. Physics reach of the Global Neutrinoless Double-Beta Decay Program and systematic uncertainties of the MAJORANA Project

    NASA Astrophysics Data System (ADS)

    Gehman, Victor M.

    2007-08-01

    We present a global analysis technique for extracting information about the mechanism underlying neutrinoless double-beta decay (0nbb) by continuing the decay rate to the ground state across a number of isotopes. To this end, we also present work in support of the MAJORANA experiment, which will look for 0nbb in 76 Ge, aimed at pushing down systematic uncertainties to the level where the inclusion of 76 Ge from MAJORANA in this analysis is possible (statistical uncertainty in any 0nbb experiment will of course be set by the exposure and half-life, [Special characters omitted.] for the isotope of interest). We proceed to enumerate likely sources of systematic uncertainty, paying particular attention to the efficacy and uncertainties for background and signal tagging via pulse shape and segmentation analysis, and background fluctuations in the MAJORANA experiment. We will also detail a proposed MAJORANA calibration program designed to reduce these systematic uncertainties. We find that this global analysis for five different 0nbb models is possible if the total uncertainty budget is less than 30% for four isotopes. If these four experiments were to reach an uncertainty budget (statistical plus systematic) of [approximate] 20%, then this analysis would require matrix element uncertainties of only [approximate] 12%. If we restrict this analysis to only light Majorana n exchange (thus testing the different matrix element calculation methods), the total uncertainty budget increases to [approximate] 64%. This leaves [approximate] 31% for the matrix element uncertainty, assuming 20% from the experimental measurement. This global analysis technique is interesting because it is independent of the absolute scale of [Special characters omitted.] for different isotopes. This means that whatever the actual level of lepton number violation in nature, we can extract information about the exchange mechanism underlying 0nbb from the pattern of the decay rates for a variety of

  20. Double beta decay of Uranium-238: Proton reactions of {sup 238}U in 5--12 MeV range. Final report, April 15, 1987--March 31, 1992

    SciTech Connect

    Turkevich, A.; Economou, T.E.

    1993-06-01

    This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of {sup 238}U to {sup 238}PU to be (2.0 {plus_minus} 0.6) {times} 10{sup 21} years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 10{sup 6} times slower than spontaneous fission, which itself is about 10{sup 6} times slower than alpha decay. The implication of this double beta decay to neutrino masses depends on uncertain theoretical calculations of the rate for such a heavy nucleus. The second part reports on yields of principal fission products from 5.6, 7.3, 9.4, and 11.5 MeV proton interactions with {sup 238}U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of {sup 238}U. At the same time, the production cross sections of {sup 238}Np at the same energies are determined. This nuclide is produced as often as fission at the lowest energy but only 3.8% as often at the highest energy.