Science.gov

Sample records for neutrino matter oscillation

  1. Nonadiabatic three-neutrino oscillations in matter

    SciTech Connect

    DOlivo, J.C.; Oteo, J.A.

    1996-07-01

    Oscillations of three neutrinos in matter are analyzed by using the Magnus expansion for the time-evolution operator. We derive a simple expression for the electron-neutrino survival probability which is applied to the examination of the effect of a third neutrino on the nonadiabatic flavor transformations. {copyright} {ital 1996 The American Physical Society.}

  2. Matter-antimatter oscillations and neutrino mass

    SciTech Connect

    Senjanovic, G.

    1982-01-01

    A discussion of neutron-antineutron (n- anti n) and hydrogen-antihydrogen (H- anti H) transitions is presented. An SU(2)/sub L/ x U(1) x SU(3)/sub c/ model with spontaneously broken global B-L symmetry is shown to predict the interesting connection between oscillation times T/sub n- anti n/, T/sub H- anti H/, neutrino mass and the mass of a doubly charged Higgs scalar. A case of B-L as a gauge symmetry is discussed in the context of SU(2)/sub L/ x SU(2)/sub R/ x U(1)/sub B-L/ x SU(3)/sub c/ gauge model, with the emphasis on matter oscillations. Finally, an analysis of Higgs mass scales in GUTS and their impact on such processes is offered.

  3. Earth matter effect on active-sterile neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Acero, Mario A.; Aguilar-Arevalo, Alexis A.; D'Olivo, J. C.

    2011-08-01

    Oscillations between active and sterile neutrinos remain as an open possibility to explain some experimental observations. In a four-neutrino mixing scheme, we use the Magnus expansion of the evolution operator to study the evolution of neutrino flavor amplitudes within the Earth. We apply this formalism to calculate the transition probabilities from active to sterile neutrinos taking into account the matter effect for a varying terrestrial density.

  4. Obtaining supernova directional information using the neutrino matter oscillation pattern

    SciTech Connect

    Scholberg, Kate; Wendell, Roger; Burgmeier, Armin

    2010-02-15

    A nearby core collapse supernova will produce a burst of neutrinos in several detectors worldwide. With reasonably high probability, the Earth will shadow the neutrino flux in one or more detectors. In such a case, for allowed oscillation parameter scenarios, the observed neutrino energy spectrum will bear the signature of oscillations in Earth matter. Because the frequency of the oscillations in energy depends on the path length traveled by the neutrinos in the Earth, an observed spectrum also contains information about the direction to the supernova. We explore here the possibility of constraining the supernova location using matter oscillation patterns observed in a detector. Good energy resolution (typical of scintillator detectors), well-known oscillation parameters, and optimistically large (but conceivable) statistics are required. Pointing by this method can be significantly improved using multiple detectors located around the globe. Although it is not competitive with neutrino-electron elastic scattering-based pointing with water Cherenkov detectors, the technique could still be useful.

  5. Compact perturbative expressions for neutrino oscillations in matter

    DOE PAGESBeta

    Denton, Peter B.; Minakata, Hisakazu; Parke, Stephen J.

    2016-06-08

    We further develop and extend a recent perturbative framework for neutrino oscillations in uniform matter density so that the resulting oscillation probabilities are accurate for the complete matter potential versus baseline divided by neutrino energy plane. This extension also gives the exact oscillation probabilities in vacuum for all values of baseline divided by neutrino energy. The expansion parameter used is related to the ratio of the solar to the atmosphericmore » $$\\Delta m^2$$ scales but with a unique choice of the atmospheric $$\\Delta m^2$$ such that certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using a mixing matrix formulation, this framework has the exceptional feature that the neutrino oscillation probability in matter has the same structure as in vacuum, to all orders in the expansion parameter. It also contains all orders in the matter potential and $$\\sin\\theta_{13}$$. It facilitates immediate physical interpretation of the analytic results, and makes the expressions for the neutrino oscillation probabilities extremely compact and very accurate even at zeroth order in our perturbative expansion. Furthermore, the first and second order results are also given which improve the precision by approximately two or more orders of magnitude per perturbative order.« less

  6. Compact perturbative expressions for neutrino oscillations in matter

    NASA Astrophysics Data System (ADS)

    Denton, Peter B.; Minakata, Hisakazu; Parke, Stephen J.

    2016-06-01

    We further develop and extend a recent perturbative framework for neutrino oscillations in uniform matter density so that the resulting oscillation probabilities are accurate for the complete matter potential versus baseline divided by neutrino energy plane. This extension also gives the exact oscillation probabilities in vacuum for all values of baseline divided by neutrino energy. The expansion parameter used is related to the ratio of the solar to the atmospheric ∆ m 2 scales but with a unique choice of the atmospheric ∆ m 2 such that certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using a mixing matrix formulation, this framework has the exceptional feature that the neutrino oscillation probability in matter has the same structure as in vacuum, to all orders in the expansion parameter. It also contains all orders in the matter potential and sin θ 13. It facilitates immediate physical interpretation of the analytic results, and makes the expressions for the neutrino oscillation probabilities extremely compact and very accurate even at zeroth order in our perturbative expansion. The first and second order results are also given which improve the precision by approximately two or more orders of magnitude per perturbative order.

  7. Simple and compact expressions for neutrino oscillation probabilities in matter

    DOE PAGESBeta

    Minakata, Hisakazu; Parke, Stephen J.

    2016-01-29

    We reformulate perturbation theory for neutrino oscillations in matter with an expansion parameter related to the ratio of the solar to the atmospheric Δm2 scales. Unlike previous works, use a renormalized basis in which certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using this perturbation theory we derive extremely compact expressions for the neutrino oscillations probabilities in matter. We find, for example, that the νe disappearance probability at this order is of a simple two flavor form with an appropriately identified mixing angle and Δm2. Furthermore, despite exceptional simplicity in their forms they accommodate all order effectsmore » θ13 and the matter potential.« less

  8. Simple and compact expressions for neutrino oscillation probabilities in matter

    SciTech Connect

    Minakata, Hisakazu; Parke, Stephen J.

    2015-05-07

    We reformulate perturbation theory for neutrino oscillations in matter with an expansion parameter related to the ratio of the solar to the atmospheric Δm2 scales. Unlike previous works, use a renormalized basis in which certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using this perturbation theory we derive extremely compact expressions for the neutrino oscillations probabilities in matter. We find, for example, that the νe disappearance probability at this order is of a simple two flavor form with an appropriately identified mixing angle and Δm2. Furthermore, despite exceptional simplicity in their forms they accommodate all order effects θ13 and the matter potential.

  9. First indication of terrestrial matter effects on solar neutrino oscillation.

    PubMed

    Renshaw, A; Abe, K; Hayato, Y; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakano, Y; Nakayama, S; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Tomura, T; Ueno, K; Yokozawa, T; Wendell, R A; Irvine, T; Kajita, T; Kaneyuki, K; Lee, K P; Nishimura, Y; Okumura, K; McLachlan, T; Labarga, L; Berkman, S; Tanaka, H A; Tobayama, S; Kearns, E; Raaf, J L; Stone, J L; Sulak, L R; Goldhabar, M; Bays, K; Carminati, G; Kropp, W R; Mine, S; Smy, M B; Sobel, H W; Ganezer, K S; Hill, J; Keig, W E; Hong, N; Kim, J Y; Lim, I T; Akiri, T; Himmel, A; Scholberg, K; Walter, C W; Wongjirad, T; Ishizuka, T; Tasaka, S; Jang, J S; Learned, J G; Matsuno, S; Smith, S N; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Takeuchi, Y; Bronner, C; Hirota, S; Huang, K; Ieki, K; Ikeda, M; Kikawa, T; Minamino, A; Nakaya, T; Suzuki, K; Takahashi, S; Fukuda, Y; Choi, K; Itow, Y; Mitsuka, G; Mijakowski, P; Hignight, J; Imber, J; Jung, C K; Yanagisawa, C; Ishino, H; Kibayashi, A; Koshio, Y; Mori, T; Sakuda, M; Yano, T; Kuno, Y; Tacik, R; Kim, S B; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Totsuka, Y; Yokoyama, M; Martens, K; Marti, Ll; Vagins, M R; Martin, J F; de Perio, P; Konaka, A; Wilking, M J; Chen, S; Zhang, Y; Wilkes, R J

    2014-03-01

    We report an indication that the elastic scattering rate of solar B8 neutrinos with electrons in the Super-Kamiokande detector is larger when the neutrinos pass through Earth during nighttime. We determine the day-night asymmetry, defined as the difference of the average day rate and average night rate divided by the average of those two rates, to be [-3.2 ± 1.1(stat) ± 0.5(syst)]%, which deviates from zero by 2.7 σ. Since the elastic scattering process is mostly sensitive to electron-flavored solar neutrinos, a nonzero day-night asymmetry implies that the flavor oscillations of solar neutrinos are affected by the presence of matter within the neutrinos' flight path. Super-Kamiokande's day-night asymmetry is consistent with neutrino oscillations for 4 × 10(-5)  eV(2) ≤ Δm 2(21) ≤ 7 × 10(-5) eV(2) and large mixing values of θ12, at the 68% C.L. PMID:24655245

  10. Matter Effects on Neutrino Oscillations in Different Supernova Models

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Hu, Li-Jun; Li, Rui-Cheng; Guo, Xin-Heng; Young, Bing-Lin

    2016-04-01

    In recent years, with the development of simulations about supernova explosion, we have a better understanding about the density profiles and the shock waves in supernovae than before. There might be a reverse shock wave, another sudden change of density except the forward shock wave, or even no shock wave, emerging in the supernova. Instead of using the expression of the crossing probability at the high resonance, PH, we have studied the matter effects on neutrino oscillations in different supernova models. In detail, we have calculated the survival probability of ve (Ps) and the conversion probability of vx (Pc) in the Schrödinger equation within a simplified two-flavor framework for a certain case, in which the neutrino transfers through the supernova matter from an initial flavor eigenstate located at the core of the supernova. Our calculations was based on the data of density in three different supernova models obtained from simulations. In our work, we do not steepen the density gradient around the border of the shock wave, which differs to what was done in most of the other simulations. It is found that the mass and the density distribution of the supernova do make a difference on the behavior of Ps and Pc. With the results of Ps and Pc, we can estimate the number of ve (and vx) remained in the beam after they go through the matter in the supernova. Supported by National Science Foundation of China under Grant Nos. 11175020 and 11275025

  11. Neutrino magnetic moment, CP violation, and flavor oscillations in matter

    NASA Astrophysics Data System (ADS)

    Pehlivan, Y.; Balantekin, A. B.; Kajino, Toshitaka

    2014-09-01

    We consider collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. We investigate the symmetries of the problem in the full three-flavor mixing scheme and in the exact many-body formulation by including the effects of CP violation and the neutrino magnetic moment. We show that, similar to the two-flavor scheme, several dynamical symmetries exist for three flavors in the single-angle approximation if the net electron background in the environment and the effects of the neutrino magnetic moment are negligible. Moreover, we show that these dynamical symmetries are present even when the CP symmetry is violated in neutrino oscillations. We explicitly write down the constants of motion through which these dynamical symmetries manifest themselves in terms of the generators of the SU(3) flavor transformations. We also show that the effects due to the CP-violating Dirac phase factor out of the many-body evolution operator and evolve independently of nonlinear flavor transformations if neutrino electromagnetic interactions are ignored. In the presence of a strong magnetic field, CP-violating effects can still be considered independently provided that an effective definition for the neutrino magnetic moment is used.

  12. Oscillations of Dirac and Majorana neutrinos in matter and a magnetic field

    SciTech Connect

    Dvornikov, Maxim; Maalampi, Jukka

    2009-06-01

    We study the evolution of massive mixed Dirac and Majorana neutrinos in matter under the influence of a transversal magnetic field. The analysis is based on relativistic quantum mechanics. We solve exactly the evolution equation for relativistic neutrinos, find the neutrino wave functions, and calculate the transition probability for spin-flavor oscillations. We analyze the dependence of the transition probability on the external fields and compare the cases of Dirac and Majorana neutrinos. The evolution of Majorana particles in vacuum is also studied and correction terms to the standard oscillation formula are derived and discussed. As a possible application of our results we discuss the spin-flavor transitions in supernovae.

  13. Analytical theory of neutrino oscillations in matter with C P violation

    NASA Astrophysics Data System (ADS)

    Johnson, Mikkel B.; Henley, Ernest M.; Kisslinger, Leonard S.

    2015-04-01

    We develop an exact analytical formulation of neutrino oscillations in matter within the framework of the standard neutrino model assuming three Dirac neutrinos. Our Hamiltonian formulation, which includes C P violation, leads to expressions for the partial oscillation probabilities that are linear combinations of spherical Bessel functions in the eigenvalue differences. The coefficients of these Bessel functions are polynomials in the neutrino CKM matrix elements, the neutrino mass differences squared, the strength of the neutrino interaction with matter, and the neutrino mass eigenvalues in matter. We give exact closed-form expressions for all partial oscillation probabilities in terms of these basic quantities. Adopting the standard neutrino model, we then examine how the exact expressions for the partial oscillation probabilities might simplify by expanding in one of the small parameters α and sin θ13 of this model. We show explicitly that for small α and sin θ13 , there are branch points in the analytic structure of the eigenvalues that lead to singular behavior of expansions near the solar and atmospheric resonances. We present numerical calculations that indicate how to use the small-parameter expansions in practice.

  14. Parametric resonance in neutrino oscillation: A guide to control the effects of inhomogeneous matter density

    NASA Astrophysics Data System (ADS)

    Koike, Masafumi; Ota, Toshihiko; Saito, Masako; Sato, Joe

    2016-08-01

    Effects of the inhomogeneous matter density on the three-generation neutrino oscillation probability are analyzed. Realistic profile of the matter density is expanded into a Fourier series. Taking in the Fourier modes one by one, we demonstrate that each mode has its corresponding target energy. The high Fourier mode selectively modifies the oscillation probability of the low-energy region. This rule is well described by the parametric resonance between the neutrino oscillation and the matter effect. The Fourier analysis gives a simple guideline to systematically control the uncertainty of the oscillation probability caused by the uncertain density of matter. Precise analysis of the oscillation probability down to the low-energy region requires accurate evaluation of the Fourier coefficients of the matter density up to the corresponding high modes.

  15. A New Neutrino Oscillation

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2011-07-01

    Starting in the late 1960s, neutrino detectors began to see signs that neutrinos, now known to come in the flavors electron ({nu}{sub e}), muon ({nu}{sub {mu}}), and tau ({nu}{sub {tau}}), could transform from one flavor to another. The findings implied that neutrinos must have mass, since massless particles travel at the speed of light and their clocks, so to speak, don't tick, thus they cannot change. What has since been discovered is that neutrinos oscillate at two distinct scales, 500 km/GeV and 15,000 km/GeV, which are defined by the baseline (L) of the experiment (the distance the neutrino travels) divided by the neutrino energy (E). Neutrinos of one flavor can oscillate into neutrinos of another flavor at both L/E scales, but the amplitude of these oscillations is different for the two scales and depends on the initial and final flavor of the neutrinos. The neutrino states that propogate unchanged in time, the mass eigenstates {nu}1, {nu}2, {nu}3, are quantum mechanical mixtures of the electron, muon, and tau neutrino flavors, and the fraction of each flavor in a given mass eigenstate is controlled by three mixing angles and a complex phase. Two of these mixing angles are known with reasonable precision. An upper bound exists for the third angle, called {theta}{sub 13}, which controls the size of the muon neutrino to electron neutrino oscillation at an L/E of 500 km/GeV. The phase is completely unknown. The existence of this phase has important implications for the asymmetry between matter and antimatter we observe in the universe today. Experiments around the world have steadily assembled this picture of neutrino oscillation, but evidence of muon neutrino to electron neutrino oscillation at 500 km/GeV has remained elusive. Now, a paper from the T2K (Tokai to Kamioka) experiment in Japan, reports the first possible observation of muon neutrinos oscillating into electron neutrinos at 500 km/GeV. They see 6 candidate signal events, above an expected background

  16. Implications of Neutrino Oscillations on the Dark-Matter World

    NASA Astrophysics Data System (ADS)

    Hwang, W.-Y. Pauchy

    2014-01-01

    According to my own belief that "The God wouldn't create a world that is so boring that a particle knows only the very feeble weak interaction.", maybe we underestimate the roles of neutrinos. We note that right-handed neutrinos play no roles, or don't exist, in the minimal Standard Model. We discuss the language to write down an extended Standard Model - using renormalizable quantum field theory as the language; to start with a certain set of basic units under a certain gauge group; in fact, to use the three right-handed neutrinos to initiate the family gauge group SUf (3). Specifically we use the left-handed and right-handed spinors to form the basic units together with SUc (3) × SUL (2) × U (1) × SUf (3) as the gauge group. The dark-matter SUf (3) world couples with the lepton world, but not with the quark world. Amazingly enough, the space of the Standard-Model Higgs Φ (1 , 2), the family Higgs triplet Φ(3, 1), and the neutral part of the mixed family Higgs Φ0 (3 , 2) undergoes the spontaneous symmetry breaking, i.e. the Standard-Model Higgs mechanism and the "project-out" family Higgs mechanism, to give rise to the weak bosons W± and Z0, one Standard-Model Higgs, the eight massive family gauge bosons, and the remaining four massive neutral family Higgs particles, and nothing more. Thus, the roles of neutrinos in this extended Standard Model are extremely interesting in connection with the dark-matter world.

  17. Consequences of an Abelian Z' for neutrino oscillations and dark matter

    NASA Astrophysics Data System (ADS)

    Plestid, Ryan

    2016-02-01

    The Standard Model's accidental and anomaly-free currents, B -L , Le-Lμ, Le-Lτ, and Lμ-Lτ, could be indicative of a hidden gauge structure beyond the Standard Model. Additionally, neutrino masses can be generated by a dimension-5 operator that generically breaks all of these symmetries. It is therefore important to investigate the compatibility of a gauged U'(1 ) and neutrino phenomenology. We consider gauging each of the symmetries above with a minimal extended matter content. This includes the Z', an order parameter to break the U'(1 ), and three right-handed neutrinos. We find all but B -L require additional matter content to explain the measured neutrino oscillation parameters. We also discuss the compatibility of the measured neutrino textures with a nonthermal dark matter production mechanism involving the decay of the Z'. Finally, we present a parametric relation that implies that any sterile neutrino dark matter candidate should not be expected to contribute to neutrino masses beyond ten parts per million.

  18. Analytical approximation of the neutrino oscillation matter effects at large θ 13

    NASA Astrophysics Data System (ADS)

    Agarwalla, Sanjib Kumar; Kao, Yee; Takeuchi, Tatsu

    2014-04-01

    We argue that the neutrino oscillation probabilities in matter are best understood by allowing the mixing angles and mass-squared differences in the standard parametrization to `run' with the matter effect parameter a = , where N e is the electron density in matter and E is the neutrino energy. We present simple analytical approximations to these `running' parameters. We show that for the moderately large value of θ 13, as discovered by the reactor experiments, the running of the mixing angle θ 23 and the CP violating phase δ can be neglected. It simplifies the analysis of the resulting expressions for the oscillation probabilities considerably. Approaches which attempt to directly provide approximate analytical expressions for the oscillation probabilities in matter suffer in accuracy due to their reliance on expansion in θ 13, or in simplicity when higher order terms in θ 13 are included. We demonstrate the accuracy of our method by comparing it to the exact numerical result, as well as the direct approximations of Cervera et al., Akhmedov et al., Asano and Minakata, and Freund. We also discuss the utility of our approach in figuring out the required baseline lengths and neutrino energies for the oscillation probabilities to exhibit certain desirable features.

  19. Berry phase in neutrino oscillations

    SciTech Connect

    He Xiaogang; McKellar, Bruce H.J.; Zhang Yue

    2005-09-01

    We study the Berry phase in neutrino oscillations for both Dirac and Majorana neutrinos. In order to have a Berry phase, the neutrino oscillations must occur in a varying medium, the neutrino-background interactions must depend on at least two independent densities, and also there must be CP violation. If the neutrino interactions with matter are mediated only by the standard model W and Z boson exchanges, these conditions imply that there must be at least three generations of neutrinos. The CP violating Majorana phases do not play a role in generating a Berry phase. We show that a natural way to satisfy the conditions for the generation of a Berry phase is to have sterile neutrinos with active-sterile neutrino mixing, in which case at least two active and one sterile neutrinos are required. If there are additional new CP violating flavor changing interactions, it is also possible to have a nonzero Berry phase with just two generations.

  20. Oscillations of solar atmosphere neutrinos

    SciTech Connect

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P. D.

    2006-11-01

    The Sun is a source of high-energy neutrinos (E(greater-or-similar sign)10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged vacuum oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23})

  1. Semiclassical treatment of matter-enhanced neutrino oscillations for an arbitrary density profile

    SciTech Connect

    Balantekin, A.B.; Beacom, J.F.

    1996-11-01

    The matter-enhanced oscillations of two neutrino flavors are studied using a uniform semiclassical approximation. Unlike some analytic studies which have focused on certain exactly solvable densities, this method can be used for an arbitrary monotonic density profile. The method is applicable to a wider range of mixing parameters than previous approximate methods for arbitrary densities. The approximation is excellent in the adiabatic regime and up to the extreme nonadiabatic limit. In particular, the range of validity for this approximation extends farther into the nonadiabatic regime than for the linear Landau-Zener result. This method also allows calculation of the source- and detector-dependent terms in the unaveraged survival probability, and analytic results for these terms are given. These interference terms may be important in studying neutrino mixing in the Sun or in supernovas. {copyright} {ital 1996 The American Physical Society.}

  2. A torsional completion of gravity for Dirac matter fields and its applications to neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fabbri, Luca; Vignolo, Stefano

    2016-01-01

    In this paper, we consider the torsional completion of gravitation for an underlying background filled with Dirac fields, applying it to the problem of neutrino oscillations: we discuss the effects of the induced torsional interactions as corrections to the neutrino oscillations mechanism.

  3. Paradoxes of neutrino oscillations

    SciTech Connect

    Akhmedov, E. Kh.; Smirnov, A. Yu.

    2009-08-15

    Despite the theory of neutrino oscillations being rather old, some of its basic issues are still being debated in the literature. We discuss a number of such issues, including the relevance of the 'same energy' and 'same momentum' assumptions, the role of quantum-mechanical uncertainty relations in neutrino oscillations, the dependence of the coherence and localization conditions that ensure the observability of neutrino oscillations on neutrino energy and momentum uncertainties, the question of (in)dependence of the oscillation probabilities on the neutrino production and detection processes, and the applicability limits of the stationary-source approximation. We also develop a novel approach to calculation of the oscillation probability in the wave-packet approach, based on the summation/integration conventions different from the standard one, which allows a new insight into the 'same energy' vs. 'same momentum' problem. We also discuss a number of apparently paradoxical features of the theory of neutrino oscillations.

  4. Neutrino Oscillations With Two Sterile Neutrinos

    NASA Astrophysics Data System (ADS)

    Kisslinger, Leonard S.

    2016-06-01

    This work estimates the probability of μ to e neutrino oscillation with two sterile neutrinos using a 5×5 U-matrix, an extension of the previous estimate with one sterile neutrino and a 4×4 U-matrix. The sterile neutrino-active neutrino mass differences and the mixing angles of the two sterile neutrinos with the three active neutrinos are taken from recent publications, and the oscillation probability for one sterile neutrino is compared to the previous estimate.

  5. Neutrino Oscillation Physics

    SciTech Connect

    Kayser, Boris

    2012-06-01

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures. Neutrinos and photons are by far the most abundant elementary particles in the universe. Thus, if we would like to comprehend the universe, we must understand the neutrinos. Of course, studying the neutrinos is challenging, since the only known forces through which these electrically-neutral leptons interact are the weak force and gravity. Consequently, interactions of neutrinos in a detector are very rare events, so that very large detectors and intense neutrino sources are needed to make experiments feasible. Nevertheless, we have confirmed that the weak interactions of neutrinos are correctly described by the Standard Model (SM) of elementary particle physics. Moreover, in the last 14 years, we have discovered that neutrinos have nonzero masses, and that leptons mix. These discoveries have been based on the observation that neutrinos can change from one 'flavor' to another - the phenomenon known as neutrino oscillation. We shall explain the physics of neutrino oscillation, deriving the probability of oscillation in a new way. We shall also provide a very brief guide to references that can be used to study some major neutrino-physics topics other than neutrino oscillation.

  6. Atmospheric neutrinos and discovery of neutrino oscillations

    PubMed Central

    Kajita, Takaaki

    2010-01-01

    Neutrino oscillation was discovered through studies of neutrinos produced by cosmic-ray interactions in the atmosphere. These neutrinos are called atmospheric neutrinos. They are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith-angle and energy dependent deficit of muon-neutrino events. Neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. Neutrino oscillations imply that neutrinos have small but non-zero masses. The small neutrino masses have profound implications to our understanding of elementary particle physics and the Universe. This article discusses the experimental discovery of neutrino oscillations. PMID:20431258

  7. Magnus approximation in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Acero, Mario A.; Aguilar-Arevalo, Alexis A.; D'Olivo, J. C.

    2011-04-01

    Oscillations between active and sterile neutrinos remain as an open possibility to explain some anomalous experimental observations. In a four-neutrino (three active plus one sterile) mixing scheme, we use the Magnus expansion of the evolution operator to study the evolution of neutrino flavor amplitudes within the Earth. We apply this formalism to calculate the transition probabilities from active to sterile neutrinos with energies of the order of a few GeV, taking into account the matter effect for a varying terrestrial density.

  8. Boxing with Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Wagner, Dj; Weiler, Thomas J.

    1998-03-01

    We have developed a model-independent ``box'' parameterization of neutrino oscillations. Oscillation probabilities are linear in these new parameters, so measurements can straighforwardly determine the box parameters which can then be manipulated to yield magnitudes of mixing matrix elements. We will present these new parameters and examine the effects of unitarity which reduce the number of independent parameters to the minimum set. The framework presented here will facilitate general analyses of neutrino oscillations among n >= 3 flavors.

  9. Coherence effects in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Kiers, Ken; Nussinov, Schmuel; Weiss, Nathan

    1996-01-01

    We study the effect of coherent and incoherent broadening on neutrino oscillations both in vacuum and in the presence of matter (the MSW effect). We show under very general assumptions that it is not possible to distinguish experimentally neutrinos produced in some region of space as wave packets from those produced in the same region of space as plane waves with the same energy distribution.

  10. CPand t violation in neutrino oscillations

    SciTech Connect

    Hisakazu Minakata; Hiroshi Nunokawa; Stephen Parke

    2003-09-18

    In this short lecture, we discuss some basic phenomenological aspects of CP and T violation in neutrino oscillation. Using CP/T trajectory diagrams in the bi-probability space, we try to sketch out some essential features of the interplay between the effect of CP/T violating phase and that of the matter in neutrino oscillation.

  11. Neutrino masses, neutrino oscillations, and cosmological implications

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1982-01-01

    Theoretical concepts and motivations for considering neutrinos having finite masses are discussed and the experimental situation on searches for neutrino masses and oscillations is summarized. The solar neutrino problem, reactor, deep mine and accelerator data, tri decay experiments and double beta-decay data are considered and cosmological implications and astrophysical data relating to neutrino masses are reviewed. The neutrino oscillation solution to the solar neutrino problem, the missing mass problem in galaxy halos and galaxy cluster galaxy formation and clustering, and radiative neutrino decay and the cosmic ultraviolet background radiation are examined.

  12. Neutrinos Matter

    NASA Astrophysics Data System (ADS)

    Freedman, Stuart

    2003-04-01

    The excitement about neutrinos is all about mass. Recent experiments have established that neutrino have mass and that the familiar weak interaction states ν_e, ν_μ, and ν_τ are not the states the quantum states with definite mass. These new discoveries require a major reassessment of the role of neutrinos in the universe and the first reformulation of the Standard Model of particle physics since the discovery of the third generation of quarks and leptons. Neutrino experiments are poised to answer many of the new questions raised by the recent discoveries. I will review the current status of the field and discuss what experiment is teaching us about neutrino mass and mixing.

  13. Neutrino Oscillations and the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Wark, David

    2001-04-01

    When the existence of the neutrino was almost apologetically first proposed by Wolfgang Pauli it was intended to explain the mysterious apparent absence of energy and momentum in beta decay. 70 years later the neutrino has indeed solved that mystery, but it has generated still more of its own. Are neutrinos massive? Is it possible to create a neutrino with its spin in the same direction as its momentum? What fraction of the mass of the Universe is made up of neutrinos? Are the flavour labels which we put on neutrinos, like electron and muon, really fixed or can they change? Why does no experiment see the predicted flux of neutrinos from the Sun? Why do there appear to be roughly equal numbers of muon and electron neutrinos created in our atmosphere, rather than the 2:1 ratio we would expect? Many of these questions were coupled when Bruno Pontecorvo first suggested that the shortfall in solar neutrino measurements were caused by neutrino oscillations - neutrinos spontaneously changing flavour as they travel from the Sun. 30 years later we still await definitive proof of that conjecture, and providing that proof is the reason for the Sudbury Neutrino Observatory. The talk will discuss the current state of neutrino oscillations studies, and show how the unique capabilities of the Sudbury Neutrino Observatory can provide definitive proof of whether neutrino oscillations are the long-sought answer to the solar neutrino problem.

  14. Running of oscillation parameters in matter with flavor-diagonal non-standard interactions of the neutrino

    NASA Astrophysics Data System (ADS)

    Agarwalla, Sanjib Kumar; Kao, Yee; Saha, Debashis; Takeuchi, Tatsu

    2015-11-01

    In this article we unravel the role of matter effect in neutrino oscillation in the presence of lepton-flavor-conserving, non-universal non-standard interactions (NSI's) of the neutrino. Employing the Jacobi method, we derive approximate analytical expressions for the effective mass-squared differences and mixing angles in matter. It is shown that, within the effective mixing matrix, the Standard Model (SM) W -exchange interaction only affects θ 12 and θ 13, while the flavor-diagonal NSI's only affect θ 23. The CP-violating phase δ remains unaffected. Using our simple and compact analytical approximation, we study the impact of the flavor-diagonal NSI's on the neutrino oscillation probabilities for various appearance and disappearance channels. At higher energies and longer baselines, it is found that the impact of the NSI's can be significant in the ν μ → ν μ channel, which can probed in future atmospheric neutrino experiments, if the NSI's are of the order of their current upper bounds. Our analysis also enables us to explore the possible degeneracy between the octant of θ 23 and the sign of the NSI parameter for a given choice of mass hierarchy in a simple manner.

  15. Boxing with neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Wagner, D. J.; Weiler, Thomas J.

    1999-06-01

    We develop a characterization of neutrino oscillations based on the coefficients of the oscillating terms. These coefficients are individually observable; although they are quartic in the elements of the unitary mixing matrix, they are independent of the conventions chosen for the angle and phase parametrization of the mixing matrix. We call these reparametrization-invariant observables ``boxes'' because of their geometric relation to the mixing matrix, and because of their association with the Feynman box diagram that describes oscillations in field theory. The real parts of the boxes are the coefficients for the CP- or T-even oscillation modes, while the imaginary parts are the coefficients for the CP- or T-odd oscillation modes. Oscillation probabilities are linear in the boxes, so measurements can straightforwardly determine values for the boxes (which can then be manipulated to yield magnitudes of mixing matrix elements). We examine the effects of unitarity on the boxes and discuss the reduction of the number of boxes to a minimum basis set. For the three-generation case, we explicitly construct the basis. Using the box algebra, we show that CP violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. The framework presented here will facilitate general analyses of neutrino oscillations among n>=3 flavors.

  16. Boxing with neutrino oscillations

    SciTech Connect

    Wagner, D.J.; Weiler, T.J.

    1999-06-01

    We develop a characterization of neutrino oscillations based on the coefficients of the oscillating terms. These coefficients are individually observable; although they are quartic in the elements of the unitary mixing matrix, they are independent of the conventions chosen for the angle and phase parametrization of the mixing matrix. We call these reparametrization-invariant observables {open_quotes}boxes{close_quotes} because of their geometric relation to the mixing matrix, and because of their association with the Feynman box diagram that describes oscillations in field theory. The real parts of the boxes are the coefficients for the {ital CP}- or {ital T}-even oscillation modes, while the imaginary parts are the coefficients for the {ital CP}- or {ital T}-odd oscillation modes. Oscillation probabilities are linear in the boxes, so measurements can straightforwardly determine values for the boxes (which can then be manipulated to yield magnitudes of mixing matrix elements). We examine the effects of unitarity on the boxes and discuss the reduction of the number of boxes to a minimum basis set. For the three-generation case, we explicitly construct the basis. Using the box algebra, we show that {ital CP} violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. The framework presented here will facilitate general analyses of neutrino oscillations among n{ge}3 flavors. {copyright} {ital 1999} {ital The American Physical Society}

  17. Calculating Neutrino Oscillations with Sterile Neutrinos

    NASA Astrophysics Data System (ADS)

    Linehan, Bryan

    2014-09-01

    In particle physics, it is currently known that three types of neutrinos exist that interact via the weak force. Referred to as ``flavors,'' they are distinguishable and named for the lepton they produce through charged current interactions: electron, muon, and tau. In a process called neutrino oscillation, one flavor of neutrino can change into another flavor as it propagates through space. At the moment, mild discrepancies between expected and measured neutrino oscillations suggest that more types of neutrinos that do not interact via the weak force exist: sterile neutrinos. The goal of this project was to calculate non-sterile flavor oscillation probabilities when 1, 2 or 3 sterile neutrinos were assumed to exist. An application has been written in Mathematica that calculates these probabilities with the neutrino masses, linear relationships between mass and flavor states, values of CP symmetry violating constants, and constant densities of media in which the neutrinos propagate set as parameters. The application was published online for researchers to use as a tool when considering the existence of sterile neutrinos. In the immediate future, the insights this application gives into neutrino oscillations will be studied and reported. In particle physics, it is currently known that three types of neutrinos exist that interact via the weak force. Referred to as ``flavors,'' they are distinguishable and named for the lepton they produce through charged current interactions: electron, muon, and tau. In a process called neutrino oscillation, one flavor of neutrino can change into another flavor as it propagates through space. At the moment, mild discrepancies between expected and measured neutrino oscillations suggest that more types of neutrinos that do not interact via the weak force exist: sterile neutrinos. The goal of this project was to calculate non-sterile flavor oscillation probabilities when 1, 2 or 3 sterile neutrinos were assumed to exist. An application

  18. Floquet Theory of Neutrino Oscillations in the Earth

    NASA Astrophysics Data System (ADS)

    Akhmedov, E. Kh.

    2001-05-01

    We review the Floquet theory of linear differential equations with periodic coefficients and discuss its applications to neutrino oscillations in matter of periodically varying density. In particular, we consider parametric resonance in neutrino oscillations which can occur in such media, and discuss implications for oscillations of neutrinos traversing the earth and passing through the earth's core.

  19. Neutrino oscillations refitted

    NASA Astrophysics Data System (ADS)

    Forero, D. V.; Tórtola, M.; Valle, J. W. F.

    2014-11-01

    Here, we update our previous global fit of neutrino oscillations by including the recent results that have appeared since the Neutrino 2012 conference. These include the measurements of reactor antineutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle θ23 is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with an emphasis on the increasing sensitivity to the C P phase, thanks to the interplay between accelerator and reactor data. In the Appendix, we present the updated results obtained after the inclusion of new reactor data presented at the Neutrino 2014 conference. We discuss their impact on the global neutrino analysis.

  20. Helicity oscillations of Dirac and Majorana neutrinos

    NASA Astrophysics Data System (ADS)

    Dobrynina, Alexandra; Kartavtsev, Alexander; Raffelt, Georg

    2016-06-01

    The helicity of a Dirac neutrino with mass m evolves under the influence of a B field because it has a magnetic dipole moment proportional to m . Moreover, it was recently shown that a polarized or anisotropic medium engenders the same effect for both Dirac and Majorana neutrinos. Because a B field polarizes a background medium, it instigates helicity oscillations even for Majorana neutrinos unless the medium is symmetric between matter and antimatter. Motivated by these observations, we review the impact of a B field and of an anisotropic or polarized medium on helicity oscillations for Dirac and Majorana neutrinos from the common perspective of in-medium dispersion.

  1. Neutrino oscillation studies with reactors

    PubMed Central

    Vogel, P.; Wen, L.J.; Zhang, C.

    2015-01-01

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos. PMID:25913819

  2. Neutrino oscillation studies with reactors

    SciTech Connect

    Vogel, P.; Wen, L.J.; Zhang, C.

    2015-04-27

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  3. Neutrino oscillation studies with reactors.

    PubMed

    Vogel, P; Wen, L J; Zhang, C

    2015-01-01

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos. PMID:25913819

  4. Neutrino oscillation studies with reactors

    DOE PAGESBeta

    Vogel, P.; Wen, L.J.; Zhang, C.

    2015-04-27

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  5. Generalized Boltzmann formalism for oscillating neutrinos

    SciTech Connect

    Strack, P.; Burrows, A.

    2005-05-01

    In the standard approaches to neutrino transport in the simulation of core-collapse supernovas, one will often start from the classical Boltzmann equation for the neutrino's spatial, temporal, and spectral evolution. For each neutrino species, and its antiparticle, the classical density in phase space, or the associated specific intensity, will be calculated as a function of time. The neutrino radiation is coupled to matter by source and sink terms on the 'right-hand side' of the transport equation and together with the equations of hydrodynamics this set of coupled partial differential equations for classical densities describes, in principle, the evolution of core collapse and explosion. However, with the possibility of neutrino oscillations between species, a purely quantum-physical effect, how to generalize this set of Boltzmann equations for classical quantities to reflect oscillation physics has not been clear. To date, the formalisms developed have retained the character of quantum operator physics involving complex quantities and have not been suitable for easy incorporation into standard supernova codes. In this paper, we derive generalized Boltzmann equations for quasiclassical, real-valued phase-space densities that retain all the standard oscillation phenomenology, including the matter-enhanced resonant flavor conversion (Mikheev-Smirnov-Wolfenstein effect), neutrino self-interactions, and the interplay between decohering matter coupling and flavor oscillations. With this formalism, any code(s) that can now handle the solution of the classical Boltzmann or transport equation can easily be generalized to include neutrino oscillations in a quantum-physically consistent fashion.

  6. Sterile neutrinos as dark matter

    SciTech Connect

    Dodelson, S.; Widrow, L.M. |

    1993-03-01

    The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed or sterile neutrinos. This model has been studied extensively in the context of the hot dark matter scenario. We reexamine this model and find that hot, warm, and cold dark matter are all possibilities. We focus on the case where sterile neutrinos are the dark matter. Since their only direct coupling is to left-handed or active neutrinos, the most efficient production mechanism is via neutrino oscillations. If the production rate is always less than the expansion rate, then these neutrinos will never be in thermal equilibrium. However, they may still play a significant role in the dynamics of the Universe and possibly provide the missing mass necessary for closure. We consider a single generation of neutrino fields ({nu}{sub L}, {nu}{sub R}) with a Dirac mass, {mu}, and a Majorana mass for the right-handed components only, M. For M {much_gt} {mu} we show that the number density of sterile neutrinos is proportional to {mu}{sup 2}/M so that the energy density today is independent of M. However M is crucial in determining the large scale structure of the Universe. In particular, M {approx_equal} 0.1--1.0 key leads to warm dark matter and a structure formation scenario that may have some advantages over both the standard hot and cold dark matter scenarios.

  7. Sterile neutrinos as dark matter

    SciTech Connect

    Dodelson, S. ); Widrow, L.M. . Dept. of Physics Toronto Univ., ON . Canadian Inst. for Theoretical Astrophysics)

    1993-03-01

    The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed or sterile neutrinos. This model has been studied extensively in the context of the hot dark matter scenario. We reexamine this model and find that hot, warm, and cold dark matter are all possibilities. We focus on the case where sterile neutrinos are the dark matter. Since their only direct coupling is to left-handed or active neutrinos, the most efficient production mechanism is via neutrino oscillations. If the production rate is always less than the expansion rate, then these neutrinos will never be in thermal equilibrium. However, they may still play a significant role in the dynamics of the Universe and possibly provide the missing mass necessary for closure. We consider a single generation of neutrino fields ([nu][sub L], [nu][sub R]) with a Dirac mass, [mu], and a Majorana mass for the right-handed components only, M. For M [much gt] [mu] we show that the number density of sterile neutrinos is proportional to [mu][sup 2]/M so that the energy density today is independent of M. However M is crucial in determining the large scale structure of the Universe. In particular, M [approx equal] 0.1--1.0 key leads to warm dark matter and a structure formation scenario that may have some advantages over both the standard hot and cold dark matter scenarios.

  8. Atmospheric neutrino oscillations for Earth tomography

    NASA Astrophysics Data System (ADS)

    Winter, Walter

    2016-07-01

    Modern proposed atmospheric neutrino oscillation experiments, such as PINGU in the Antarctic ice or ORCA in Mediterranean sea water, aim for precision measurements of the oscillation parameters including the ordering of the neutrino masses. They can, however, go far beyond that: Since neutrino oscillations are affected by the coherent forward scattering with matter, neutrinos can provide a new view on the interior of the earth. We show that the proposed atmospheric oscillation experiments can measure the lower mantle density of the earth with a precision at the level of a few percent, including the uncertainties of the oscillation parameters and correlations among different density layers. While the earth's core is, in principle, accessible by the angular resolution, new technology would be required to extract degeneracy-free information.

  9. Results from Neutrino Oscillations Experiments

    SciTech Connect

    Aguilar-Arevalo, Alexis

    2010-09-10

    The interpretation of the results of early solar and atmospheric neutrino experiments in terms of neutrino oscillations has been verified by several recent experiments using both, natural and man-made sources. The observations provide compelling evidence in favor of the existence of neutrino masses and mixings. These proceedings give a general description of the results from neutrino oscillation experiments, the current status of the field, and some possible future developments.

  10. Current trends in non-accelerator particle physics: 1, Neutrino mass and oscillation. 2, High energy neutrino astrophysics. 3, Detection of dark matter. 4, Search for strange quark matter. 5, Magnetic monopole searches

    SciTech Connect

    He, Yudong |

    1995-07-01

    This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.

  11. Spectrometry of the Earth using neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Taketa, Akimichi; Rott, Carsten

    2016-04-01

    Neutrinos have favorable properties for measuring the elemental composition deep inside the earth's interior. First, they propagate a long distance almost undisturbed through the earth due to their weak interactions with matter. Secondly, neutrino oscillations in matter are sensitive to the electron density of the medium traversed by them. Therefore, neutrinos can be used for a probe to determine the average atomic mass ratio Z/A of the earth's core by comparing with the earth's nucleus density distribution that is inferred from seismic observations. There is a little uncertainty in densities of the earth's core, but our knowledge of its main light element is still not fixed. With the advent of the new-generation megaton neutrino detectors, neutrino oscillation mass spectrometry will allow us to constrain directly the light elements in the earth's outer core. We report the detail of this novel technic and the sensitivity study.

  12. Neutrino Oscillations:. Hierarchy Question

    NASA Astrophysics Data System (ADS)

    Ernst, D. J.; Cogswell, B. K.; Burroughs, H. R.; Escamilla-Roa, J.; Latimer, D. L.

    2014-09-01

    The only experimentally observed phenomenon that lies outside the standard model of the electroweak interaction is neutrino oscillations. A way to try to unify the extensive neutrino oscillation data is to add a phenomenological mass term to the Lagrangian that is not diagonal in the flavor basis. The goal is then to understand the world's data in terms of the parameters of the mixing matrix and the differences between the squares of the masses of the neutrinos. An outstanding question is what is the correct ordering of the masses, the hierarchy question. We point out a broken symmetry relevant to this question, the symmetry of the simultaneous interchange of hierarchy and the sign of θ13. We first present the results of an analysis of data that well determine the phenomenological parameters but are not sensitive to the hierarchy. We find θ13 = 0.152±0.014, θ 23 = 0.25{ - 0.05}{ + 0.03} π and Δ32 = 2.45±0.14×10-3 eV2, results consistent with others. We then include data that are sensitive to the hierarchy and the sign of θ13. We find, unlike others, four isolated minimum in the χ2-space as predicted by the symmetry. Now that Daya Bay and RENO have determined θ13 to be surprisingly large, the Super-K atmospheric data produce meaningful symmetry breaking such that the inverse hierarchy is preferred at the 97.2 % level.

  13. Flavor oscillations with sterile neutrinos and in dense neutrino environments

    NASA Astrophysics Data System (ADS)

    Hollander, David

    that the mixing parameters for the three Standard Model neutrino flavors are well known, some implications of neutrino interactions for flavor oscillations are not well understood. Neutrinos can interact with one another in a similar way to how neutrinos interact with normal matter. Neutrino-neutrino forward scattering can lead to a flavor swap for the propagating neutrino, or the propagating neutrino can retain its original flavor. These interactions contribute an effective potential to the Hamiltonian describing the flavor evolution which depends on a background neutrino density. In normal matter the neutrino density is very low which allows for neutrino-neutrino interactions to be ignored, however these interactions can dominate over vacuum and normal matter interactions in very dense environments such as core-collapse supernovae and early universe scenarios. Neutrino-neutrino interactions give rise to terms quadratic in neutrino densities in the equations of motion, and can give rise to what is called collective oscillations resulting from interference with vacuum and normal matter effects. The non-linearity has made the problem of solving for collective oscillations analytically intractable without simplifying assumptions, and has made this a problem relegated to supercomputer simulations. This dissertation is concerned with analytic methods for solving the equations of motion for core-collapse neutrino propagation. It will be shown here that, by keeping only nunu-interactions at initial distances outward from the supernova core, it is possible to solve the equations of motion by factorizing vacuum oscillations and the effects of nunu-interactions. Furthermore, it will be shown how using this factorization scheme it is possible to predict where flavor oscillations become unstable. This is an important development because it can allow one to predict the neutrino flux in Earth experiments from core-collapse supernovae, while at the same time gaining an understanding

  14. Neutrino Oscillations in the Case of General Interaction

    NASA Astrophysics Data System (ADS)

    Syska, J.; Zajac, S.; Zrałek, M.

    2007-11-01

    The process of the neutrino production, oscillation in the vacuum or in matter, and detection in the case of interactions which are beyond the Standard Model is considered. Neutrino states are described by the density matrix. The final neutrino production rate does not factorize. The known Maki-Nakagawa-Sakata neutrino states and the factorized production rate are recovered in the nu SM regime.

  15. LSND neutrino oscillation results

    SciTech Connect

    Louis, W.C.; LSND Collaboration

    1996-10-01

    The LSND (Liquid Scintillator Neutrino Detector) experiment at Los Alamos has conducted a search for muon antineutrino {r_arrow} electron antineutrino oscillations using muon neutrinos from antimuon decay at rest. The electron antineutrinos are detected via the reaction electron antineutrino + proton {r_arrow} positron + neutron, correlated with the 2.2-MeV gamma from neutron + proton {r_arrow} deuteron + gamma. The use of tight cuts to identify positron events with correlated gamma rays yields 22 events with positron energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup -8}. A chi-squared fit to the entire positron sample results in a total excess of 51.8 {sup +18.7}{sub -16.9} {+-} 8.0 events with positron energy between 20 and 60 MeV. If attributed to muon antineutrino {r_arrow} electron antineutrino oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31 {+-} 0.12 {+-} 0.05){percent}. 10 refs., 7 figs., 1 tab.

  16. Neutrinos and dark matter

    SciTech Connect

    Ibarra, Alejandro

    2015-07-15

    Neutrinos could be key particles to unravel the nature of the dark matter of the Universe. On the one hand, sterile neutrinos in minimal extensions of the Standard Model are excellent dark matter candidates, producing potentially observable signals in the form of a line in the X-ray sky. On the other hand, the annihilation or the decay of dark matter particles produces, in many plausible dark matter scenarios, a neutrino flux that could be detected at neutrino telescopes, thus providing non-gravitational evidence for dark matter. More conservatively, the non-observation of a significant excess in the neutrino fluxes with respect to the expected astrophysical backgrounds can be used to constrain dark matter properties, such as the self-annihilation cross section, the scattering cross section with nucleons and the lifetime.

  17. Neutrino Oscillations with Three Active and Three Sterile Neutrinos

    NASA Astrophysics Data System (ADS)

    Kisslinger, Leonard S.

    2016-07-01

    This is an extension of estimates of the probability of μ to e neutrino oscillation with one sterile neutrino to three sterile neutrinos, using a 6x6 matrix. Since the mixing angle for only one sterile neutrino has been experimentally determined, we estimate the μ to e neutrino oscillation probability with different mixing angles for two of the sterile neutrinos.

  18. Prospects for detecting supernova neutrino flavor oscillations

    NASA Astrophysics Data System (ADS)

    Fuller, George M.; Haxton, Wick C.; McLaughlin, Gail C.

    1999-04-01

    The neutrinos from a type II supernova provide perhaps our best opportunity to probe cosmologically interesting muon and/or tauon neutrino masses. This is because matter enhanced neutrino oscillations can lead to an anomalously hot νe spectrum, and thus to enhanced charged current cross sections in terrestrial detectors. Two recently proposed supernova neutrino observatories, OMNIS and LAND, will detect neutrons spalled from target nuclei by neutral and charged current neutrino interactions. As this signal is not flavor specific, it is not immediately clear whether a convincing neutrino oscillation signal can be extracted from such experiments. To address this issue we examine the responses of a series of possible light and heavy mass targets, 9Be,23Na,35Cl, and 208Pb. We find that strategies for detecting oscillations which use only neutron count rates are problematic at best, even if cross sections are determined by ancillary experiments. Plausible uncertainties in supernova neutrino spectra tend to obscure rate enhancements due to oscillations. However, in the case of 208Pb, a signal emerges that is largely flavor specific and extraordinarily sensitive to the νe temperature, the emission of two neutrons. This signal and its flavor specificity are associated with the strength and location of the first-forbidden responses for neutral and charge current reactions, aspects of the 208Pb neutrino cross section that have not been discussed previously. Hadronic spin transfer experiments might be helpful in confirming some of the nuclear structure physics underlying our conclusions.

  19. Analytical approximations for matter effects on CP violation in the accelerator-based neutrino oscillations with E ≲ 1 GeV

    NASA Astrophysics Data System (ADS)

    Xing, Zhi-zhong; Zhu, Jing-yu

    2016-07-01

    Given an accelerator-based neutrino experiment with the beam energy E ≲ 1 GeV, we expand the probabilities of ν μ → ν e and {overline{ν}}_{μ}to {overline{ν}}_e oscillations in matter in terms of two small quantities Δ21 /Δ31 and A/Δ31, where Δ 21≡ m 2 2 - m 1 2 and Δ 31≡ m 3 2 - m 1 2 are the neutrino mass-squared differences, and A measures the strength of terrestrial matter effects. Our analytical approximations are numerically more accurate than those made by Freund in this energy region, and thus they are particularly applicable for the study of leptonic CP violation in the low-energy MOMENT, ESS νSM and T2K oscillation experiments. As a by-product, the new analytical approximations help us to easily understand why the matter-corrected Jarlskog parameter tilde{J} peaks at the resonance energy E ∗ ≃ 0 .14GeV (or 0 .12 GeV) for the normal (or inverted) neutrino mass hierarchy, and how the three Dirac unitarity triangles are deformed due to the terrestrial matter contamination. We also affirm that a medium-baseline neutrino oscillation experiment with the beam energy E lying in the E ∗ ≲ E ≲ 2 E ∗ range is capable of exploring leptonic CP violation with little matter-induced suppression.

  20. Analyzing Atmospheric Neutrino Oscillations

    SciTech Connect

    Escamilla, J.; Ernst, D. J.; Latimer, D. C.

    2007-10-26

    We provide a pedagogic derivation of the formula needed to analyze atmospheric data and then derive, for the subset of the data that are fully-contained events, an analysis tool that is quantitative and numerically efficient. Results for the full set of neutrino oscillation data are then presented. We find the following preliminary results: 1.) the sub-dominant approximation provides reasonable values for the best fit parameters for {delta}{sub 32}, {theta}{sub 23}, and {theta}{sub 13} but does not quantitatively provide the errors for these three parameters; 2.) the size of the MSW effect is suppressed in the sub-dominant approximation; 3.) the MSW effect reduces somewhat the extracted error for {delta}{sub 32}, more so for {theta}{sub 23} and {theta}{sub 13}; 4.) atmospheric data alone constrains the allowed values of {theta}{sub 13} only in the sub-dominant approximation, the full three neutrino calculations requires CHOOZ to get a clean constraint; 5.) the linear in {theta}{sub 13} terms are not negligible; and 6.) the minimum value of {theta}{sub 13} is found to be negative, but at a statistically insignificant level.

  1. Supernova neutrino oscillations: A simple analytical approach

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Montanino, D.; Palazzo, A.

    2002-04-01

    Analyses of observable supernova neutrino oscillation effects require the calculation of the electron (anti)neutrino survival probability Pee along a given supernova matter density profile. We propose a simple analytical prescription for Pee, based on a double-exponential form for the crossing probability and on the concept of maximum violation of adiabaticity. In the case of two-flavor transitions, the prescription is shown to reproduce accurately, in the whole neutrino oscillation parameter space, the results of exact numerical calculations for generic (realistic or power-law) profiles. The analytical approach is then generalized to cover three-flavor transitions with (direct or inverse) mass spectrum hierarchy, and to incorporate Earth matter effects. Compact analytical expressions, explicitly showing the symmetry properties of Pee, are provided for practical calculations.

  2. Neutrino oscillation results from MINOS

    SciTech Connect

    Sousa, Alexandre; /Oxford U.

    2007-08-01

    The Main Injector Neutrino Oscillation Search (MINOS) long-baseline experiment has been actively collecting beam data since 2005, having already accumulated 3 x 10{sup 20} protons-on-target (POT). MINOS uses the Neutrinos at the Main Injector (NuMI) neutrino beam measured in two locations: at Fermilab, close to beam production, and 735 km downstream, in Northern Minnesota. By observing the oscillatory structure in the neutrino energy spectrum, MINOS can precisely measure the neutrino oscillation parameters in the atmospheric sector. These parameters were determined to be |{Delta}m{sub 32}{sup 2}| = 2.74{sub -0.26}{sup +0.44} x 10{sup -3} eV{sup 2}/c{sup 4} and sin{sup 2}(2{theta}{sub 23}) > 0.87 (68% C.L.) from analysis of the first year of data, corresponding to 1.27 x 10{sup 20} POT.

  3. Oscillating asymmetric dark matter

    SciTech Connect

    Tulin, Sean; Yu, Hai-Bo; Zurek, Kathryn M. E-mail: haiboyu@umich.edu

    2012-05-01

    We study the dynamics of dark matter (DM) particle-antiparticle oscillations within the context of asymmetric DM. Oscillations arise due to small DM number-violating Majorana-type mass terms, and can lead to recoupling of annihilation after freeze-out and washout of the DM density. Asymmetric DM oscillations 'interpolate' between symmetric and asymmetric DM freeze-out scenarios, and allow for a larger DM model-building parameter space. We derive the density matrix equations for DM oscillations and freeze-out from first principles using nonequilibrium field theory, and our results are qualitatively different than in previous studies. DM dynamics exhibits particle-vs-antiparticle 'flavor' effects, depending on the interaction type, analogous to neutrino oscillations in a medium. 'Flavor-sensitive' DM interactions include scattering or annihilation through a new vector boson, while 'flavor-blind' interactions include scattering or s-channel annihilation through a new scalar boson. In particular, we find that flavor-sensitive annihilation does not recouple when coherent oscillations begin, and that flavor-blind scattering does not lead to decoherence.

  4. Spectrometry of the Earth using Neutrino Oscillations.

    PubMed

    Rott, C; Taketa, A; Bose, D

    2015-01-01

    The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth's inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth's electron density. The Earth's chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth's matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways. PMID:26489447

  5. Supernova neutrinos: production, oscillations and detection

    NASA Astrophysics Data System (ADS)

    Mirizzi, A.; Tamborra, I.; Janka, H.-Th.; Saviano, N.; Scholberg, K.; Bollig, R.; Hüdepohl, L.; Chakraborty, S.

    Neutrinos play a crucial role in the collapse and explosion of massive stars, governing the infall dynamics of the stellar core, triggering and fueling the explosion and driving the cooling and deleptonization of the newly formed neutron star. Due to their role neutrinos carry information from the heart of the explosion and, due to their weakly interacting nature, offer the only direct probe of the dynamics and thermodynamics at the center of a supernova. In this paper, we review the present status of modelling the neutrino physics and signal formation in collapsing and exploding stars. We assess the capability of current and planned large underground neutrino detectors to yield faithful information of the time and flavor-dependent neutrino signal from a future Galactic supernova. We show how the observable neutrino burst would provide a benchmark for fundamental supernova physics with unprecedented richness of detail. Exploiting the treasure of the measured neutrino events requires a careful discrimination of source-generated properties from signal features that originate on the way to the detector. As for the latter, we discuss self-induced flavor conversions associated with neutrino-neutrino interactions that occur in the deepest stellar regions; matter effects that modify the pattern of flavor conversions in the dynamical stellar envelope; neutrino-oscillation signatures that result from structural features associated with the shock-wave propagation as well as turbulent mass motions in post-shock layers. Finally, we highlight our current understanding of the formation of the diffuse supernova neutrino background and we analyse the perspectives for a detection of this relic signal that integrates the contributions from all past core-collapse supernovae in the Universe.

  6. An analytical treatment for three neutrino oscillations in the Earth

    NASA Astrophysics Data System (ADS)

    Aguilar-Arevalo, A. A.; D'Olivo, J. C.; Supanitsky, A. D.

    2012-08-01

    A simple, and at the same time accurate, description of the Earth matter effects on the oscillations between three neutrino flavors is given in terms of the Magnus expansion for the evolution operator.

  7. Why is the neutrino oscillation formula expanded in Δ m {21/2}/Δ m {31/2} still accurate near the solar resonance in matter?

    NASA Astrophysics Data System (ADS)

    Xu, Xun-Jie

    2015-10-01

    The conventional approximate formula for neutrino oscillation in matter which is obtained from the expansion in terms of the ratio of mass square differences α = Δ m 21 2 /Δ m 31 2 ≈ 0.03, first proposed by Cervera, et al. and Freund, turns out to be an accurate formula for accelerator neutrino experiments. Originally it required the neutrino energy to be well above the solar resonance to validate the expansion but it is found to be still very accurate when the formula is extrapolated to the resonance, which is practically important for the T2K experiment. This paper shows that the accuracy is guaranteed by cancellations of branch cut singularities and also, for the first time, analytically computes the actual error of the formula. The actual error implies that the original requirement can be safely removed in current experiments.

  8. Sterile neutrino dark matter production in the neutrino-phillic two Higgs doublet model

    NASA Astrophysics Data System (ADS)

    Adulpravitchai, Adisorn; Schmidt, Michael A.

    2015-12-01

    Sterile Neutrinos with a mass in the keV range form a good candidate for dark matter. They are naturally produced from neutrino oscillations via their mixing with the active neutrinos. However the production via non-resonant neutrino oscillations has recently been ruled out. The alternative production via Higgs decay is negligibly small compared to neutrino oscillations. We show that in the neutrino-phillic two Higgs doublet model, the contribution from Higgs decay can dominate over the contribution from neutrino oscillations and evade all constraints. We also study the free-streaming horizon and find that a sterile neutrino mass in the range of 4 to 53 keV leads to warm dark matter.

  9. Evidence for neutrino oscillations in the Sudbury Neutrino Observatory

    SciTech Connect

    Marino, Alysia Diane

    2004-08-10

    The Sudbury Neutrino Observatory (SNO) is a large-volume heavy water Cerenkov detector designed to resolve the solar neutrino problem. SNO observes charged-current interactions with electron neutrinos, neutral-current interactions with all active neutrinos, and elastic-scattering interactions primarily with electron neutrinos with some sensitivity to other flavors. This dissertation presents an analysis of the solar neutrino flux observed in SNO in the second phase of operation, while {approx}2 tonnes of salt (NaCl) were dissolved in the heavy water. The dataset here represents 391 live days of data. Only the events above a visible energy threshold of 5.5 MeV and inside a fiducial volume within 550 cm of the center of the detector are studied. The neutrino flux observed via the charged-current interaction is [1.71 {+-} 0.065(stat.){+-}{sub 0.068}{sup 0.065}(sys.){+-}0.02(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}, via the elastic-scattering interaction is [2.21{+-}0.22(stat.){+-}{sub 0.12}{sup 0.11}(sys.){+-}0.01(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}, and via the neutral-current interaction is [5.05{+-}0.23(stat.){+-}{sub 0.37}{sup 0.31}(sys.){+-}0.06(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}. The electron-only flux seen via the charged-current interaction is more than 7{sigma} below the total active flux seen via the neutral-current interaction, providing strong evidence that neutrinos are undergoing flavor transformation as they travel from the core of the Sun to the Earth. The most likely origin of the flavor transformation is matter-induced flavor oscillation.

  10. Neutrino oscillations as a probe of dark energy.

    PubMed

    Kaplan, David B; Nelson, Ann E; Weiner, Neal

    2004-08-27

    We consider a class of theories in which neutrino masses depend significantly on environment, as a result of interactions with the dark sector. Such theories of mass varying neutrinos were recently introduced to explain the origin of the cosmological dark energy density and why its magnitude is apparently coincidental with that of neutrino mass splittings. In this Letter we argue that in such theories neutrinos can exhibit different masses in matter and in vacuum, dramatically affecting neutrino oscillations. As an example of modifications to the standard picture, we consider simple models that may simultaneously account for the LSND anomaly, KamLAND, K2K, and studies of solar and atmospheric neutrinos, while providing motivation to continue to search for neutrino oscillations in short baseline experiments such as BooNE. PMID:15447091

  11. Measuring neutrino oscillation parameters using $\

    SciTech Connect

    Backhouse, Christopher James

    2011-01-01

    MINOS is a long-baseline neutrino oscillation experiment. It consists of two large steel-scintillator tracking calorimeters. The near detector is situated at Fermilab, close to the production point of the NuMI muon-neutrino beam. The far detector is 735 km away, 716m underground in the Soudan mine, Northern Minnesota. The primary purpose of the MINOS experiment is to make precise measurements of the 'atmospheric' neutrino oscillation parameters (Δmatm2 and sin2atm). The oscillation signal consists of an energy-dependent deficit of vμ interactions in the far detector. The near detector is used to characterize the properties of the beam before oscillations develop. The two-detector design allows many potential sources of systematic error in the far detector to be mitigated by the near detector observations. This thesis describes the details of the vμ-disappearance analysis, and presents a new technique to estimate the hadronic energy of neutrino interactions. This estimator achieves a significant improvement in the energy resolution of the neutrino spectrum, and in the sensitivity of the neutrino oscillation fit. The systematic uncertainty on the hadronic energy scale was re-evaluated and found to be comparable to that of the energy estimator previously in use. The best-fit oscillation parameters of the vμ-disappearance analysis, incorporating this new estimator were: Δm2 = 2.32-0.08+0.12 x 10-3 eV2, sin 2 2θ > 0.90 (90% C.L.). A similar analysis, using data from a period of running where the NuMI beam was operated in a configuration producing a predominantly $\\bar{v}$μ beam, yielded somewhat different best-fit parameters Δ$\\bar{m}${sup 2} = (3.36-0.40+0.46(stat.) ± 0.06(syst.)) x 10-3eV2, sin2 2$\\bar{θ}$ = 0.86-0.12_0.11

  12. Multipole expansion method for supernova neutrino oscillations

    SciTech Connect

    Duan, Huaiyu; Shalgar, Shashank E-mail: shashankshalgar@unm.edu

    2014-10-01

    We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.

  13. LSND neutrino oscillation results

    SciTech Connect

    White, D.H.; LSND Collaboration

    1997-11-01

    The LSND experiment at Los Alamos has conducted a search for {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations using {anti v}{sub {mu}} from {mu}{sup +} decay at rest. The {anti v}{sub e} are detected via the reaction {anti v}{sub e} p {yields} e{sup +}n, correlated with the 2.2 MeV {gamma} from n p {yields} d {gamma}. The use of tight cuts to identify e{sup +} events with correlated {gamma} rays yielded 22 events with e{sup +} energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup {minus}8}. A {chi}{sup 2} fit to the entire e{sup +} sample results in a total excess of 51.8{sub {minus}16.9}{sup +18.7} {+-} 8.0 events with e{sup +} energy between 20 and 60 MeV. If attributed to {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.31 {+-} 0.12 {+-} 0.05%.

  14. Atmospheric neutrinos in ice and measurement of neutrino oscillation parameters

    SciTech Connect

    Fernandez-Martinez, Enrique; Giordano, Gerardo; Mocioiu, Irina; Mena, Olga

    2010-11-01

    The main goal of the IceCube Deep Core array is to search for neutrinos of astrophysical origins. Atmospheric neutrinos are commonly considered as a background for these searches. We show that the very high statistics atmospheric neutrino data can be used to obtain precise measurements of the main oscillation parameters.

  15. Another look at synchronized neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny; Mirizzi, Alessandro

    2016-07-01

    In dense neutrino backgrounds present in supernovae and in the early Universe neutrino oscillations may exhibit complex collective phenomena, such as synchronized oscillations, bipolar oscillations and spectral splits and swaps. We consider in detail possible decoherence effects on the simplest of these phenomena - synchronized neutrino oscillations that can occur in a uniform and isotropic neutrino gas. We develop an exact formalism of spectral moments of the flavour spin vectors describing such a system and then apply it to find analytical approaches that allow one to study decoherence effects on its late-time evolution. This turns out to be possible in part due to the existence of the (previously unknown) exact conservation law satisfied by the quantities describing the considered neutrino system. Interpretation of the decoherence effects in terms of neutrino wave packet separation is also given, both in the adiabatic and non-adiabatic regimes of neutrino flavour evolution.

  16. Neutrino Oscillations: Eighty Years in Review

    NASA Astrophysics Data System (ADS)

    Bowers, Rebecca Lyn

    In order to discuss neutrino oscillations, it is necessary to have knowledge of the developments in the field spanning the last eighty years. The existence of the neutrino was posited by Wolfgang Pauli in 1930 to account for the mass defect in beta decay, and to this day physicists are still endeavoring to answer fundamental questions about this enigmatic particle. The scope of this thesis includes a historical background of neutrino physics and a discussion of neutrinos and the Standard Model; subsequent to this is a discussion of the Solar Neutrino Problem, which provided the impetus for the proposal of neutrino oscillations. Bolstering the theory of neutrino oscillations (which is developed in the body of this thesis) are neutrino detector experiments and their results; these include the Homestake experiment, SNO, Kamiokande and Super-Kamiokande, MINOS, and Double-Chooz. We also include relevant derivations, most particularly of the quantum mechanics of neutrino oscillations as treated in the wave packet formalism. We have amassed here the principle theories and experimental results -- a mere tip of the iceberg -- that have brought us to our current understanding of neutrino oscillations. We have also studied the quantum mechanics of neutrino oscillations and developed for ourselves the wave packet formalism describing the phenomenon.

  17. Subpanel on accelerator-based neutrino oscillation experiments

    SciTech Connect

    1995-09-01

    Neutrinos are among nature`s fundamental constituents, and they are also the ones about which we know least. Their role in the universe is widespread, ranging from the radioactive decay of a single atom to the explosions of supernovae and the formation of ordinary matter. Neutrinos might exhibit a striking property that has not yet been observed. Like the back-and-forth swing of a pendulum, neutrinos can oscillate to-and-from among their three types (or flavors) if nature provides certain conditions. These conditions include neutrinos having mass and a property called {open_quotes}mixing.{close_quotes} The phenomenon is referred to as neutrino oscillations. The questions of the origin of neutrino mass and mixing among the neutrino flavors are unsolved problems for which the Standard Model of particle physics holds few clues. It is likely that the next critical step in answering these questions will result from the experimental observation of neutrino oscillations. The High Energy Physics Advisory Panel (HEPAP) Subpanel on Accelerator-Based Neutrino Oscillation Experiments was charged to review the status and discovery potential of ongoing and proposed accelerator experiments on neutrino oscillations, to evaluate the opportunities for the U.S. in this area of physics, and to recommend a cost-effective plan for pursuing this physics, as appropriate. The complete charge is provided in Appendix A. The Subpanel studied these issues over several months and reviewed all the relevant and available information on the subject. In particular, the Subpanel reviewed the two proposed neutrino oscillation programs at Fermi National Accelerator Laboratory (Fermilab) and at Brookhaven National Laboratory (BNL). The conclusions of this review are enumerated in detail in Chapter 7 of this report. The recommendations given in Chapter 7 are also reproduced in this summary.

  18. FINAL NEUTRINO OSCILLATION RESULTS FROM LSND

    SciTech Connect

    W. LOUIS

    2000-10-01

    The LSND experiment provides evidence for neutrino oscillations from both the primary {bar {nu}}{sub {mu}} {r_arrow} {bar {nu}}{sub e} oscillation search and the secondary {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillation search. At present, this remains the only evidence for appearance neutrino oscillations and implies that at least one neutrino has a mass greater than 0.4 eV/c{sup 2} and that neutrinos comprise more than 1% of the mass of the universe. The MiniBooNE experiment at Fermilab, which is presently under construction, will provide a definitive test of the LSND results, and if the neutrino oscillation results are confirmed, will make a precision measurement of the oscillation parameters.

  19. NuCraft: Oscillation probabilities for atmospheric neutrinos calculator

    NASA Astrophysics Data System (ADS)

    Wallraff, Marius

    2016-02-01

    NuCraft calculates oscillation probabilities for atmospheric neutrinos, taking into account matter effects and the Earth's atmosphere, and supports an arbitrary number of sterile neutrino flavors with easily configurable continuous Earth models. Continuous modeling of the Earth instead of the often-used approximation of four layers with constant density and consideration of the smearing of baseline lengths due to the variable neutrino production heights in Earth's atmosphere each lead to deviations of 10% or more for conventional neutrinos between 1 and 10 GeV.

  20. Neutrino oscillation studies at LAMPF

    SciTech Connect

    Louis, W.C.; LSND Collaboration

    1994-09-01

    A search for {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations has been made by the Liquid Scintillator Neutrino Detector experiment at LAMPF after an initial month and a half run. The experiment observes eight events consistent with the reaction {anti v}{sub e}p {yields} e{sup +}n followed by np {yields} d{gamma} (2.2 MeV). The total estimated background is 0.9{plus_minus}0.2 events.

  1. Spectrometry of the Earth using Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Rott, C.; Taketa, A.; Bose, D.

    2015-10-01

    The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth’s inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth’s electron density. The Earth’s chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth’s matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways.

  2. Spectrometry of the Earth using Neutrino Oscillations

    PubMed Central

    Rott, C.; Taketa, A.; Bose, D.

    2015-01-01

    The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth’s inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth’s electron density. The Earth’s chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth’s matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways. PMID:26489447

  3. Neutrino clouds and dark matter

    SciTech Connect

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

    1996-12-31

    We have examined the consequences of assuming the existence of a light scalar boson, weakly coupled to neutrinos, and not coupled to any other light fermions. For a range of parameters, we find that this hypothesis leads to the development of neutrino clusters which form in the early Universe and which provide gravitational fluctuations on scales small compared to a parsec (i.e., the scale of solar systems). Under some conditions, this can produce anomalous gravitational acceleration within solar systems and lead to a vanishing of neutrino mass-squared differences, giving rise to strong neutrino oscillation effects.

  4. Neutrino oscillations and the seesaw origin of neutrino mass

    NASA Astrophysics Data System (ADS)

    Miranda, O. G.; Valle, J. W. F.

    2016-07-01

    The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, has brought neutrino physics to the precision era. We note that CP effects in oscillation phenomena could be difficult to extract in the presence of unitarity violation. As a result upcoming dedicated leptonic CP violation studies should take into account the non-unitarity of the lepton mixing matrix. Restricting non-unitarity will shed light on the seesaw scale, and thereby guide us towards the new physics responsible for neutrino mass generation.

  5. Neutrino oscillations in the presence of super-light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Divari, Paraskevi; Vergados, John

    2016-07-01

    In this paper, we study the effect of conversion of super-light sterile neutrino (SLSN) to electron neutrino in matter like that of the Earth. In the Sun the resonance conversion between SLSN and electron neutrino via the neutral current is suppressed due to the smallness of neutron number. On the other hand, neutron number density can play an important role in the Earth, making the scenario of SLSN quite interesting. The effect of CP-violating phases on active-SLSN oscillations is also discussed. Reactor neutrino experiments with medium or short baseline may probe the scenario of SLSN.

  6. Uncovering the matter-neutrino resonance

    NASA Astrophysics Data System (ADS)

    Väänänen, D.; McLaughlin, G. C.

    2016-05-01

    Matter-neutrino resonances (MNRs) can drastically modify neutrino flavor evolution in astrophysical environments and may significantly impact nucleosynthesis. Here we further investigate the underlying physics of MNR-type flavor transitions. We provide generalized resonance conditions and make analytical predictions for the behavior of the system. We discuss the adiabatic evolution of these transitions considering both symmetric and standard MNR scenarios. Symmetric MNR transitions differ from standard MNR transitions in that both neutrinos and antineutrinos can completely transform to other flavors simultaneously. We provide an example of the simplest system in which such transitions can occur with a neutrino and an antineutrino having a single energy and emission angle. We further apply linearized stability analysis to predict the location of self-induced nutation-type (or bipolar) oscillations due to ν ν interactions in the regions where MNR is ineffective. In all cases, we compare our analytical predictions to numerical calculations.

  7. Collective neutrino oscillations in supernovae

    SciTech Connect

    Duan, Huaiyu

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  8. Cosmological bounds on dark-matter-neutrino interactions

    SciTech Connect

    Mangano, Gianpiero; Melchiorri, Alessandro; Serra, Paolo; Cooray, Asantha; Kamionkowski, Marc

    2006-08-15

    We investigate the cosmological effects of a neutrino interaction with cold dark-matter. We postulate a neutrino that interacts with a ''neutrino-interacting dark-matter'' (NIDM) particle with an elastic-scattering cross section that either decreases with temperature as T{sup 2} or remains constant with temperature. The neutrino-dark-matter interaction results in a neutrino-dark-matter fluid with pressure, and this pressure results in diffusion-damped oscillations in the matter power spectrum, analogous to the acoustic oscillations in the baryon-photon fluid. We discuss the bounds from the Sloan Digital Sky Survey on the NIDM opacity (ratio of cross section to NIDM-particle mass) and compare with the constraint from observation of neutrinos from supernova 1987A. If only a fraction of the dark matter interacts with neutrinos, then NIDM oscillations may affect current cosmological constraints from measurements of galaxy clustering. We discuss how detection of NIDM oscillations would suggest a particle-antiparticle asymmetry in the dark-matter sector.

  9. Sterile neutrinos as the origin of dark and baryonic matter.

    PubMed

    Canetti, Laurent; Drewes, Marco; Shaposhnikov, Mikhail

    2013-02-01

    We demonstrate for the first time that three sterile neutrinos alone can simultaneously explain neutrino oscillations, the observed dark matter, and the baryon asymmetry of the Universe without new physics above the Fermi scale. The key new point of our analysis is leptogenesis after sphaleron freeze-out, which leads to resonant dark matter production, evading thus the constraints on sterile neutrino dark matter from structure formation and x-ray searches. We identify the range of sterile neutrino properties that is consistent with all known constraints. We find a domain of parameters where the new particles can be found with present day experimental techniques, using upgrades to existing experimental facilities. PMID:23432234

  10. Effects of Neutrino Decay on Oscillation Probabilities

    NASA Astrophysics Data System (ADS)

    Leonard, Kayla; de Gouvêa, André

    2016-01-01

    It is now well accepted that neutrinos oscillate as a quantum mechanical result of a misalignment between their mass-eigenstates and the flavor-eigenstates. We study neutrino decay—the idea that there may be new, light states that the three Standard Model flavors may be able to decay into. We consider what effects this neutrino decay would have on the observed oscillation probabilities.The Hamiltonian governs how the states change with time, so we use it to calculate an oscillation amplitude, and from that, the oscillation probability. We simplify the theoretical probabilities using results from experimental data, such as the neutrino mixing angles and mass differences. By exploring what values of the decay parameters are physically allowable, we can begin to understand just how large the decay parameters can be. We compare the probabilities in the case of no neutrino decay and in the case of maximum neutrino decay to determine how much of an effect neutrino decay could have on observations, and discuss the ability of future experiments to detect these differences.We also examine neutrino decay in the realm of CP invariance, and found that it is a new source of CP violation. Our work indicates that there is a difference in the oscillation probabilities between particle transitions and their corresponding antiparticle transitions. If neutrino decay were proven true, it could be an important factor in understanding leptogenesis and the particle-antiparticle asymmetry present in our Universe.

  11. Neutrino oscillations: From a historical perspective to the present status

    NASA Astrophysics Data System (ADS)

    Bilenky, S.

    2016-07-01

    The history of neutrino mixing and oscillations is briefly presented. Basics of neutrino mixing and oscillations and convenient formalism of neutrino oscillations in vacuum are given. The role of neutrino in the Standard Model and the Weinberg mechanism of the generation of the Majorana neutrino masses are discussed.

  12. Decoherence and oscillations of supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kersten, Jörn; Smirnov, Alexei Yu.

    2016-06-01

    Supernova neutrinos have several exceptional features which can lead to interesting physical consequences. At the production point their wave packets have an extremely small size σ x ˜ 10^{-11} cm; hence the energy uncertainty can be as large as the energy itself, σ E ˜ E, and the coherence length is short. On the way to the Earth the wave packets of mass eigenstates spread to macroscopic sizes and separate. Inside the Earth the mass eigenstates split into eigenstates in matter and oscillate again. The coherence length in the Earth is comparable with the radius of the Earth. We explore these features and their consequences. (1) We present new estimates of the wave packet size. (2) We consider the decoherence condition for the case of wave packets with spatial spread and show that it is not modified by the spread. (3) We study the coherence of neutrinos propagating in a multi-layer medium with density jumps at the borders of layers. In this case coherence can be partially restored due to a "catch-up effect", increasing the coherence length beyond the usual estimate. This catch-up effect can occur for supernova neutrinos as they cross the shock wave fronts in the exploding star or the core of the Earth.

  13. A study of neutrino oscillations in MINOS

    SciTech Connect

    Raufer, Tobias Martin; /Oxford U.

    2007-06-01

    MINOS is a long-baseline neutrino oscillations experiment located at Fermi National Accelerator Laboratory (FNAL), USA. It makes use of the NuMI neutrino beamline and two functionally identical detectors located at distances of {approx}1km and {approx}735km from the neutrino production target respectively. The Near Detector measures the composition and energy spectrum of the neutrino beam with high precision while the Far Detector looks for evidence of neutrino oscillations. This thesis presents work conducted in two distinct areas of the MINOS experiment: analysis of neutral current and charged current interactions. While charged current events are only sensitive to muon neutrino disappearance, neutral current events can be used to distinguish oscillations into sterile neutrinos from those involving only active neutrino species. A complete, preliminary neutral current study is performed on simulated data. This is followed by a more detailed investigation of neutral current neutrino interactions in the MINOS Near Detector. A procedure identifying neutral current interactions and rejecting backgrounds due to reconstruction failures is developed. Two distinct event classification methods are investigated. The selected neutral current events in the Near Detector are used to extract corrections to the neutral current cross-section in the MINOS Monte Carlo simulation as a function of energy. The resulting correction factors are consistent with unity. The main MINOS charged current neutrino disappearance analysis is described. We present the Monte Carlo tuning procedure, event selection, extrapolation from Near to Far Detector and fit for neutrino oscillations. Systematic errors on this measurement are evaluated and discussed in detail. The data are consistent with neutrino oscillations with the following parameters: 2.74 {sup +0.44}{sub -0.26} x 10{sup -3} eV{sup 2} and sin{sup 2}(2{theta}{sub 23}) > 0.87 at 68% confidence level.

  14. Nuclear effects in neutrino oscillation experiments

    SciTech Connect

    Chauhan, S.; Athar, M. Sajjad; Singh, S. K.

    2011-10-06

    We have studied the nuclear medium effects in the neutrino(antineutrino) induced interactions in nuclei which are relevant for present neutrino oscillation experiments in the few GeV energy region. The study is specially focused on calculating the cross sections and the event rates for atmospheric and accelerator neutrino experiments. The nuclear effects are found to be important for the quasielastic lepton production and the charged current incoherent and coherent pion production processes.

  15. Impact of Neutrino Oscillation Measurements on Theory

    SciTech Connect

    Murayama, Hitoshi

    2003-11-30

    Neutrino oscillation data had been a big surprise to theorists, and indeed they have ongoing impact on theory. I review what the impact has been, and what measurements will have critical impact on theory in the future.

  16. Neutrino mixing and oscillations in astrophysical environments

    SciTech Connect

    Balantekin, A. B.

    2014-05-02

    A brief review of the current status of neutrino mixing and oscillations in astrophysical environments, with particular emphasis on the Sun and core-collapse supernovae, is given. Implications of the existence of sterile states which mix with the active neutrinos are discussed.

  17. Nuclear Propelled Vessels and Neutrino Oscillation Experiments

    NASA Astrophysics Data System (ADS)

    Detwiler, J.; Gratta, G.; Tolich, N.; Uchida, Y.

    2002-10-01

    We study the effect of naval nuclear reactors on the study of neutrino oscillations. We find that the presence of naval reactors at unknown locations and times may limit the accuracy of future very long baseline reactor-based neutrino oscillation experiments. At the same time, we argue that a nuclear powered surface ship such as a large Russian icebreaker may provide an ideal source for precision experiments.

  18. Reproducing sterile neutrinos and the behavior of flavor oscillations with superconducting-magnetic proximity effects

    NASA Astrophysics Data System (ADS)

    Baker, Thomas E.

    2016-03-01

    The physics of a superconductor subjected to a magnetic field is known to be equivalent to neutrino oscillations. Examining the properties of singlet-triplet oscillations in the magnetic field, a sterile neutrino is suggested to be represented by singlet Cooper pairs and moderates flavor oscillations between three flavor neutrinos (triplet Cooper pairs). A superconductor-exchange spring system's rotating magnetization profile is used to simulate the mass-flavor oscillations in the neutrino case and the physics of neutrino oscillations are discussed. Connecting the condensed matter system and the particle physics system with this analogy may allow for the properties of the condensed matter system to inform neutrino experiments. Support is graciously acknowledged from the Pat Beckman Memorial Scholarship from the Orange County Chapter of the Achievement Rewards for College Scientists Foundation.

  19. Neutrino interactions in neutron matter

    NASA Astrophysics Data System (ADS)

    Cipollone, Andrea

    2012-12-01

    Neutrino flow is the dominant mechanism of energy transfer in the latest stages of supernovae explosions and in compact stars. The Standard Model of particle physics and accelerator data, provide a satisfactory description of neutrino physics in vacuum up to TeV scale. Nevertheless modeling the dynamics of neutrino interaction in the nuclear environment involves severe difficulties. This thesis in mainly aimed at obtaining the weak response of infinite matter, using both the Correlated Basis Function theory and Landau Theory of Fermi liquid to take into account properly nucleon-nucleon hard core potential and long range correlation (quasi-particle, collective modes, ecc.)

  20. Measuring Neutrino Oscillations with Nuclear Reactors

    SciTech Connect

    McKeown, R. D.

    2007-10-26

    Since the first direct observations of antineutrino events by Reines and Cowan in the 1950's, nuclear reactors have been an important tool in the study of neutrino properties. More recently, the study of neutrino oscillations has been a very active area of research. The pioneering observation of oscillations by the KamLAND experiment has provided crucial information on the neutrino mixing matrix. New experiments to study the remaining unknown mixing angle are currently under development. These recent studies and potential future developments will be discussed.

  1. Establishing atmospheric neutrino oscillations with Super-Kamiokande

    NASA Astrophysics Data System (ADS)

    Kajita, T.; Kearns, E.; Shiozawa, M.

    2016-07-01

    In this article we review the discovery of atmospheric neutrino oscillation by the Super-Kamiokande experiment. This review outlines the sequence of observations and their associated publications that solved the atmospheric neutrino anomaly and established the existence of neutrino oscillations with nearly maximal mixing of muon neutrinos and tau neutrinos. We also discuss subsequent and ongoing studies that use atmospheric neutrinos to continue to reveal the nature of the neutrino.

  2. Neutrino oscillation above a black hole accretion disk

    SciTech Connect

    Malkus, A.; Kneller, J. P.; McLaughlin, G. C.; Surman, R.

    2015-05-15

    We examine neutrino oscillations in the context of an accretion disk surrounding a black hole. Because accretion disks produce large quantities of neutrinos, they may be home to interesting neutrino oscillation as well. We model accretion disks associated with stellar collapse for the sake of understanding neutrino oscillations. We find that the neutrino oscillations include phenomena seen in the protoneutron star setting as well as phenomena not seen elsewhere.

  3. Connecting leptonic unitarity triangle to neutrino oscillation

    NASA Astrophysics Data System (ADS)

    He, Hong-Jian; Xu, Xun-Jie

    2014-04-01

    The leptonic unitarity triangle (LUT) provides a geometric description of CP violations in the lepton-neutrino sector and is directly measurable in principle. In this paper, we reveal that the angles in the LUT have definite physical meaning, and demonstrate the exact connection of the LUT to neutrino oscillations. For the first time, we prove that these leptonic angles act as phase shifts in neutrino oscillations, by shifting Δm2L/2E to Δm2L/2E +α, where (L,E,α) denote the baseline length, neutrino energy and corresponding angle of the LUT. Each LUT has three independent parameters and contains only partial information of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix. We demonstrate that the partial information in each LUT can describe the corresponding neutrino oscillation. Hence, for the first time, we uncover that any given kind of neutrino oscillations contains at most three (rather than four) independent degrees of freedom from the PMNS matrix, and this may provide a cleaner way for fitting the corresponding oscillation data.

  4. Relic neutrino decoupling with flavour oscillations revisited

    NASA Astrophysics Data System (ADS)

    de Salas, Pablo F.; Pastor, Sergio

    2016-07-01

    We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the neutrino density matrix, including for the first time the proper collision integrals for both diagonal and off-diagonal elements. This improved calculation modifies the evolution of the off-diagonal elements of the neutrino density matrix and changes the deviation from equilibrium of the frozen neutrino spectra. However, it does not vary the contribution of neutrinos to the cosmological energy density in the form of radiation, usually expressed in terms of the effective number of neutrinos, Neff. We find a value of Neff = 3.045, in agreement with previous theoretical calculations and consistent with the latest analysis of Planck data. This result does not depend on the ordering of neutrino masses. We also consider the effect of non-standard neutrino-electron interactions (NSI), predicted in many theoretical models where neutrinos acquire mass. For two sets of NSI parameters allowed by present data, we find that Neff can be reduced down to 3.040 or enhanced up to 3.059.

  5. Long-baseline neutrino oscillation experiments

    SciTech Connect

    Crane, D.; Goodman, M.

    1994-12-31

    There is no unambiguous definition for long baseline neutrino oscillation experiments. The term is generally used for accelerator neutrino oscillation experiments which are sensitive to {Delta}m{sup 2} < 1.0 eV{sup 2}, and for which the detector is not on the accelerator site. The Snowmass N2L working group met to discuss the issues facing such experiments. The Fermilab Program Advisory Committee adopted several recommendations concerning the Fermilab neutrino program at their Aspen meeting immediately prior to the Snowmass Workshop. This heightened the attention for the proposals to use Fermilab for a long-baseline neutrino experiment at the workshop. The plan for a neutrino oscillation program at Brookhaven was also thoroughly discussed. Opportunities at CERN were considered, particularly the use of detectors at the Gran Sasso laboratory. The idea to build a neutrino beam from KEK towards Superkamiokande was not discussed at the Snowmass meeting, but there has been considerable development of this idea since then. Brookhaven and KEK would use low energy neutrino beams, while FNAL and CERN would plan have medium energy beams. This report will summarize a few topics common to LBL proposals and attempt to give a snapshot of where things stand in this fast developing field.

  6. Accelerator-based neutrino oscillation experiments

    SciTech Connect

    Harris, Deborah A.; /Fermilab

    2007-12-01

    Neutrino oscillations were first discovered by experiments looking at neutrinos coming from extra-terrestrial sources, namely the sun and the atmosphere, but we will be depending on earth-based sources to take many of the next steps in this field. This article describes what has been learned so far from accelerator-based neutrino oscillation experiments, and then describe very generally what the next accelerator-based steps are. In section 2 the article discusses how one uses an accelerator to make a neutrino beam, in particular, one made from decays in flight of charged pions. There are several different neutrino detection methods currently in use, or under development. In section 3 these are presented, with a description of the general concept, an example of such a detector, and then a brief discussion of the outstanding issues associated with this detection technique. Finally, section 4 describes how the measurements of oscillation probabilities are made. This includes a description of the near detector technique and how it can be used to make the most precise measurements of neutrino oscillations.

  7. Parametric enhancement of flavor oscillation in a three-neutrino framework

    NASA Astrophysics Data System (ADS)

    Merfeld, Kara M.; Latimer, David C.

    2014-12-01

    When neutrinos travel through matter with a periodic density profile, the neutrino oscillation probability can be enhanced if certain conditions are satisfied. In a two-neutrino framework, the condition for parametric resonance is known. Herein, we consider the analogous parametric resonance condition within the context of a full three-neutrino framework with two oscillation scales. For energies in the range of hundreds of MeV to a few GeV, we find that neutrino oscillation can be parametrically enhanced if two approximate relations are satisfied. The first is similar to the two-neutrino parametric resonance condition while the second involves the other oscillation scale. Treating the Earth's density as piecewise constant, we show that oscillations in this energy range can be enhanced between two- and threefold.

  8. Neutrino Oscillations Effects in the Context of Accretion Disks

    NASA Astrophysics Data System (ADS)

    Malkus, Annelise

    2013-10-01

    Neutrino oscillation effects due to the interaction of neutrinos with one another are diverse and depend strongly on having high densities of neutrinos. Accretion disks, which can arise from neutron star mergers or certain supernovae, are a setting where neutrino emission is high enough to be home to many of the neutrino-neutrino interaction effects seen in the early universe and supernova settings. Meanwhile, they lend themselves to additional effects not seen in other settings. We look in depth at one such effect, where the neutrino-neutrino interaction occurs at the same scale as the neutrino-electron interaction that can also influence oscillation.

  9. Neutrino oscillations in a turbulent plasma

    SciTech Connect

    Mendonça, J. T.; Haas, F.

    2013-07-15

    A new model for the joint neutrino flavor and plasma oscillations is introduced, in terms of the dynamics of the neutrino flavor polarization vector in a plasma background. Fundamental solutions are found for both time-invariant and time-dependent media, considering slow and fast variations of the electron plasma density. The model is shown to be described by a generalized Hamiltonian formalism. In the case of a broad spectrum of electron plasma waves, a statistical approach indicates the shift of both equilibrium value and frequency oscillation of flavor coherence, due to the existence of a turbulent plasma background.

  10. OPERA neutrino oscillation search: Status and perspectives

    NASA Astrophysics Data System (ADS)

    Gornushkin, Yu.

    2016-07-01

    OPERA is a long-baseline neutrino experiment at the Gran Sasso laboratory (LNGS) designed to search for ν_{{μ}}^{} → ν_{{τ}}^{} oscillations in a direct appearance mode on an event by event basis. OPERA took data in 2008-2012 with the CNGS neutrino beam from CERN. The data analysis is ongoing, with the goal of establishing ν_{{τ}}^{} appearance with a high significance. Complementary studies of the ν_{{μ}}^{} → ν_{{e}}^{} oscillations and atmospheric muons fluxes were performed as well. Current results of the experiment are presented and perspectives discussed.

  11. Neutrino masses and sterile neutrino dark matter from the PeV scale

    NASA Astrophysics Data System (ADS)

    Roland, Samuel B.; Shakya, Bibhushan; Wells, James D.

    2015-12-01

    We show that active neutrino masses and a keV-GeV mass sterile neutrino dark matter candidate can result from a modified, low energy seesaw mechanism if right-handed neutrinos are charged under a new symmetry broken by a scalar field vacuum expectation value at the PeV scale. The dark matter relic abundance can be obtained through active-sterile oscillation, freeze-in through the decay of the heavy scalar, or freeze-in via nonrenormalizable interactions at high temperatures. The low energy effective theory maps onto the widely studied ν MSM framework.

  12. Supernova constraints on neutrino oscillation and EoS for proto-neutron star

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

    2014-05-01

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We here discuss how to determine the neutrino temperatures and propose a method to determine still unknown neutrino oscillation parameters, mass hierarchy and θ13, simultaneously. Combining the recent experimental constraints on θ13 with isotopic ratios of the light elements discovered in presolar grains from the Murchison meteorite, we show that our method suggests at a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  13. Supernova constraints on neutrino oscillation and EoS for proto-neutron star

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-02

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We here discuss how to determine the neutrino temperatures and propose a method to determine still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. Combining the recent experimental constraints on θ{sub 13} with isotopic ratios of the light elements discovered in presolar grains from the Murchison meteorite, we show that our method suggests at a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  14. Neutrinos, Dark Matter and Nuclear Detection

    SciTech Connect

    Goldstein, W H; Bernstein, A; Craig, W W; Johnson, M

    2007-05-29

    Solutions to problems in nuclear non-proliferation and counter-terrorism may be found at the forefront of modern physics. Neutrino oscillation experiments, dark matter searches, and high energy astrophysics, are based on technology advances that have may also have application to nuclear detection. The detection problems share many characteristics, including energy scales, time structures, particle-type, and, of course, the combination of high backgrounds and low signal levels. This convergence of basic and applied physics is realized in non-proliferation and homeland security projects at Lawrence Livermore National Laboratory. Examples described here include reactor anti-neutrino monitoring, dual-phase noble liquid TPC development, gamma-ray telescopes, and nuclear resonance fluorescence.

  15. Neutrino Propagation in Dense Magnetized Matter

    NASA Astrophysics Data System (ADS)

    Arbuzova, E. V.; Lobanov, A. E.; Murchikova, E. M.

    2009-01-01

    We obtained a complete system of solutions of the Dirac-Pauli equation for a massive neutrino interacting with dense matter and strong electromagnetic field. We demonstrated that these solutions can describe precession of the neutrino spin.

  16. KamLAND's precision neutrino oscillation measurements

    NASA Astrophysics Data System (ADS)

    Decowski, M. P.

    2016-07-01

    The KamLAND experiment started operation in the Spring of 2002 and is operational to this day. The experiment observes signals from electron antineutrinos from distant nuclear reactors. The program, spanning more than a decade, allowed the determination of LMA-MSW as the solution to the solar neutrino transformation results (under the assumption of CPT invariance) and the measurement of various neutrino oscillation parameters. In particular, the solar mass-splitting Δ m212 was determined to high precision. Besides the study of neutrino oscillation, KamLAND started the investigation of geologically produced antineutrinos (geo-ν‾e). The collaboration also reported on a variety of other topics related to particle and astroparticle physics.

  17. Collective neutrino oscillations in nonspherical geometry

    SciTech Connect

    Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro; Raffelt, Georg

    2008-08-01

    The rich phenomenology of collective neutrino oscillations has been studied only in one-dimensional or spherically symmetric systems. Motivated by the nonspherical example of coalescing neutron stars, presumably the central engines of short gamma-ray bursts, we use the Liouville equation to formulate the problem for general source geometries. Assuming the neutrino ensemble displays self-maintained coherence, the problem once more becomes effectively one-dimensional along the streamlines of the overall neutrino flux. This approach for the first time provides a formal definition of the 'single-angle approximation' frequently used for supernova neutrinos and allows for a natural generalization to nonspherical geometries. We study the explicit example of a disk-shaped source as a proxy for coalescing neutron stars.

  18. Higgs Boson Mass, Neutrino Oscillations and Inflation

    SciTech Connect

    Shafi, Qaisar

    2008-11-23

    Finding the Standard Model scalar (Higgs) boson is arguably the single most important mission of the LHC. I review predictions for the Higgs boson mass based on stability and perturbativity arguments, taking into account neutrino oscillations. Primordial inflation based on the Coleman-Weinberg potential is briefly discussed.

  19. High intensity neutrino oscillation facilities in Europe

    NASA Astrophysics Data System (ADS)

    Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chancé, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A. C.; Kravchuk, V. L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T. Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S. K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gómez Cadenas, J. J.; Hernández, P.; Martín-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernández Martinez, E.; Maltoni, M.; Menéndez, J.; Giunti, C.; González García, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; López Pavón, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L. J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J. J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J. S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-01

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ- beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  20. Influence of flavor oscillations on neutrino beam instabilities

    SciTech Connect

    Mendonça, J. T.; Haas, F.; Bret, A.

    2014-09-15

    We consider the collective neutrino plasma interactions and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual interaction between neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.

  1. Some comments on high precision study of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Bilenky, S. M.

    2015-07-01

    I discuss here some problems connected with the high precision study of neutrino oscillations. In the general case of n-neutrino mixing I derive a convenient expression for transition probability in which only independent terms (and mass-squared differences) enter. For three-neutrino mixing I discuss a problem of a definition of a large (atmospheric) neutrino mass-squared difference. I comment also possibilities to reveal the character of neutrino mass spectrum in future reactor neutrino experiments.

  2. Oscillations of very low energy atmospheric neutrinos

    SciTech Connect

    Peres, Orlando L. G.; Smirnov, A. Yu.

    2009-06-01

    There are several new features in the production, oscillations, and detection of the atmospheric neutrinos of low energies E < or approx. 100 MeV. The flavor ratio r of muon to electron neutrino fluxes is substantially smaller than 2 and decreases with energy, a significant part of events is due to the decay of invisible muons at rest, etc. Oscillations in a two-layer medium (atmosphere-Earth) should be taken into account. We derive analytical and semianalytical expressions for the oscillation probabilities of these 'sub-sub-GeV' neutrinos. The energy spectra of the e-like events in water Cherenkov detectors are computed, and the dependence of the spectra on the 2-3 mixing angle {theta}{sub 23}, the 1-3 mixing, and the CP-violation phase are studied. We find that variations of {theta}{sub 23} in the presently allowed region change the number of e-like events by about 15%-20% as well as lead to distortion of the energy spectrum. The 1-3 mixing and CP violation can lead to {approx}10% effects. Detailed study of the sub-sub-GeV neutrinos will be possible in future megaton-scale detectors.

  3. Short distance neutrino oscillations with Borexino

    NASA Astrophysics Data System (ADS)

    Caminata, A.; Agostini, M.; Altenmüller, K.; Appel, S.; Bellini, G.; Benziger, J.; Berton, N.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Cavalcante, P.; Chepurnov, A.; Cribier, M.; D'Angelo, D.; Davini, S.; Derbin, A.; di Noto, L.; Durero, M.; Empl, A.; Etenko, A.; Farinon, S.; Fischer, V.; Fomenko, K.; Franco, D.; Gabriele, F.; Gaffiot, J.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Göger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, Th.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonquères, N.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Lehnert, B.; Link, J.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Maneschg, W.; Marcocci, S.; Maricic, J.; Mention, G.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Rossi, N.; Schönert, S.; Scola, L.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Veyssière, C.; Vivier, M.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Winter, J.; Wojcik, M.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

    2016-07-01

    The Borexino detector has convincingly shown its outstanding performances in the low energy, sub-MeV regime through its unprecedented accomplishments in the solar and geo-neutrinos detection. These performances make it the ideal tool to accomplish a state-of-the-art experiment able to test unambiguously the long-standing issue of the existence of a sterile neutrino, as suggested by the several anomalous results accumulated over the past two decades, i.e. the outputs of the LSND and Miniboone experiments, the results of the source calibration of the two Gallium solar neutrino experiments, and the recently hinted reactor anomaly. The SOX project will exploit two sources, based on Chromium and Cerium, respectively, which deployed under the experiment, in a location foreseen on purpose at the time of the construction of the detector, will emit two intense beams of neutrinos (Cr) and anti-neutrinos (Ce). Interacting in the active volume of the liquid scintillator, each beam would create an unmistakable spatial wave pattern in case of oscillation of the νe (or ν̅e) into the sterile state: such a pattern would be the smoking gun proving the existence of the new sterile member of the neutrino family. Otherwise, its absence will allow setting a very stringent limit on its existence.

  4. Calculation of oscillation probabilities of atmospheric neutrinos using nuCraft

    NASA Astrophysics Data System (ADS)

    Wallraff, Marius; Wiebusch, Christopher

    2015-12-01

    NuCraft (nucraft.hepforge.org) is an open-source Python project that calculates neutrino oscillation probabilities for neutrinos from cosmic-ray interactions in the atmosphere for their propagation through Earth. The solution is obtained by numerically solving the Schrödinger equation. The code supports arbitrary numbers of neutrino flavors including additional sterile neutrinos, CP violation, arbitrary mass hierarchies, matter effects with a configurable continuous Earth model, and takes into account the production height distribution of neutrinos in the Earth's atmosphere.

  5. Quantum correlations in terms of neutrino oscillation probabilities

    NASA Astrophysics Data System (ADS)

    Alok, Ashutosh Kumar; Banerjee, Subhashish; Uma Sankar, S.

    2016-08-01

    Neutrino oscillations provide evidence for the mode entanglement of neutrino mass eigenstates in a given flavour eigenstate. Given this mode entanglement, it is pertinent to consider the relation between the oscillation probabilities and other quantum correlations. In this work, we show that all the well-known quantum correlations, such as the Bell's inequality, are directly related to the neutrino oscillation probabilities. The results of the neutrino oscillation experiments, which measure the neutrino survival probability to be less than unity, imply Bell's inequality violation.

  6. Solar neutrinos results and oscillation analysis from Super-Kamiokande

    NASA Astrophysics Data System (ADS)

    Koshio, Yusuke

    The results of the solar neutrino spectrum measurement in Super-Kamiokande is presented. The precise measurement of the solar neutrino enegy spectrum is one of the most important key issue to understand neutrino oscillations. In order to measure the spectrum, it is very important to precisely determin the energy scale of the detector. For this purpose, we have used an electron LINAC. This calibration can be done at several positions, directions and energy points, and it can reduce the systematic errors of energy scale less than 1. Neutrino oscillations are essentially energy dependent phenomena. Actually different solar neutrino oscillation solutions require the different energy dependece. In addition, such a measurement is independent the absolute flux results of solar models. Therefore an observation of the deviation from the expected energy spectrum not only show the definite evidence of the solar neutrino oscillation, but also differenciate the possible oscillation solutions. The results of the extensive analysis on neutrino oscillation is presented.

  7. Resolving Standard and Nonstandard CP Violation Phases in Neutrino Oscillations

    SciTech Connect

    Gago, A. M.; Minakata, H.; Uchinami, S.; Nunokawa, H.; Zukanovich Funchal, R.

    2010-03-30

    Neutrino oscillations can exhibit extra CP violation effects, beyond those expected from the standard Kobayashi-Maskawa phase delta, if non-standard neutrino interactions are at play. We show that it is possible to disentangle the two CP violating effects by measuring muon neutrino appearance using a near-far two detector setting in a neutrino factory experiment.

  8. Neutrino oscillations with MINOS and MINOS+

    NASA Astrophysics Data System (ADS)

    Whitehead, L. H.

    2016-07-01

    The MINOS experiment ran from 2003 until 2012 and collected a data sample including 10.71 ×1020 protons-on-target (POT) of beam neutrinos, 3.36 ×1020 POT of beam antineutrinos and an atmospheric neutrino exposure of 37.88 kt yrs. The final measurement of the atmospheric neutrino oscillation parameters, Δ m322 and θ23, came from a full three flavour oscillation analysis of the combined CC νμ and CC ν‾μ beam and atmospheric samples and the CC νe and CC ν‾e appearance samples. This analysis yielded the most precise measurement of the atmospheric mass splitting Δ m322 performed to date. The results are | Δ m322 | = [ 2.28- 2.46 ] ×10-3 eV2 (68%) and sin2 ⁡θ23 = 0.35- 0.65 (90%) in the normal hierarchy, and | Δ m322 | = [ 2.32- 2.53 ] ×10-3 eV2 (68%) and sin2 ⁡θ23 = 0.34- 0.67 (90%) in the inverted hierarchy. The successor to MINOS in the NOνA era at FNAL, MINOS+, is now collecting data mostly in the 3- 10 GeV region, and an analysis of νμ disappearance using the first 2.99 ×1020 POT of data produced results very consistent with those from MINOS. Future data will further test the standard neutrino oscillation paradigm and allow for improved searches for exotic phenomena including sterile neutrinos, large extra dimensions and non-standard interactions.

  9. Oscillation of Very Low Energy Atmospheric Neutrinos

    SciTech Connect

    Peres, Orlando L. G.

    2010-03-30

    We discuss the oscillation effects of sub-sub-GeV atmospheric neutrinos, the sample with energies E < or approx. 100 MeV. The energy spectra of the e-like events in water Cherenkov detectors are computed and dependence of the spectra on the 2-3 mixing angle, theta{sub 23}, the 1-3 mixing and CP-violation phase are studied.

  10. Massive neutrinos, Lorentz invariance dominated standard model and the phenomenological approach to neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Šoln, Josip

    2009-08-01

    For the electroweak interactions, the massive neutrino perturbative kinematical procedure is developed in the massive neutrino Fock space. The perturbation expansion parameter is the ratio of neutrino mass to its energy. This procedure, within the Pontecorvo-Maki-Nakagawa-Sakata (PMNS)-modified electroweak Lagrangian, calculates the cross-sections with the new neutrino energy projection operators in the massive neutrino Fock space, resulting in the dominant Lorentz invariant standard model massless flavor neutrino cross-sections. As a consequence of the kinematical relations between the massive and massless neutrinos, some of the neutrino oscillation cross-sections are Lorentz invariance violating. But all these oscillating cross-sections, some of which violate the flavor conservation, being proportional to the squares of neutrino masses are practically unobservable in the laboratory. However, these neutrino oscillating cross-sections are consistent with the original Pontecorvo neutrino oscillating transition probability expression at short time (baseline), as presented by Dvornikov. From these comparisons, by mimicking the time dependence of the original Pontecorvo neutrino oscillating transition probability, one can formulate the dimensionless neutrino intensity-probability I, by phenomenologically extrapolating the time t, or, equivalently the baseline distance L away from the collision point for the oscillating differential cross-section. For the incoming neutrino of 10 MeV in energy and neutrino masses from Fritzsch analysis with the neutrino mixing matrix of Harrison, Perkins and Scott, the baseline distances at the first two maxima of the neutrino intensity are Lsime281 and 9279 km. The intensity I at the first maximum conserves the flavor, while at the second maximum, the intensities violate the flavor, respectively, in the final and initial state. At the end some details are given as to how one should be able to verify experimentally these neutrino

  11. Astronomical constraints on properties of sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Chan, M. H.; Chu, M.-C.

    2011-04-01

    We consider sterile neutrinos as a component of dark matter in the Milky Way and clusters, and compare their rest mass, decay rate and the mixing angle. A radiative decaying rate of order Γ˜10-19 s-1 for sterile neutrino rest mass m s =18-19 keV can satisfactorily account for the cooling flow problem and heating source in Milky Way center simultaneously. Also, these ranges of decay rate and rest mass match the prediction of the mixing angle sin 22 θ˜10-3 with a low reheating temperature in the inflation model, which enables the sterile-active neutrino oscillation to be visible in future experiments. However, decaying sterile neutrinos have to be ruled out as a major component of dark matter because of the high decay rate.

  12. Radiative neutrino mass, dark matter, and leptogenesis

    SciTech Connect

    Gu Peihong; Sarkar, Utpal

    2008-05-15

    We propose an extension of the standard model, in which neutrinos are Dirac particles and their tiny masses originate from a one-loop radiative diagram. The new fields required by the neutrino mass generation also accommodate the explanation for the matter-antimatter asymmetry and dark matter in the Universe.

  13. Precision Measurements of Long-Baseline Neutrino Oscillation at LBNF

    DOE PAGESBeta

    Worcester, Elizabeth

    2015-08-06

    In a long-baseline neutrino oscillation experiment, the primary physics objectives are to determine the neutrino mass hierarchy, to determine the octant of the neutrino mixing angle θ23, to search for CP violation in neutrino oscillation, and to precisely measure the size of any CP-violating effect that is discovered. This presentation provides a brief introduction to these measurements and reports on efforts to optimize the design of a long-baseline neutrino oscillation experiment, the status of LBNE, and the transition to an international collaboration at LBNF.

  14. Precision Measurements of Long-Baseline Neutrino Oscillation at LBNF

    SciTech Connect

    Worcester, Elizabeth

    2015-08-06

    In a long-baseline neutrino oscillation experiment, the primary physics objectives are to determine the neutrino mass hierarchy, to determine the octant of the neutrino mixing angle θ23, to search for CP violation in neutrino oscillation, and to precisely measure the size of any CP-violating effect that is discovered. This presentation provides a brief introduction to these measurements and reports on efforts to optimize the design of a long-baseline neutrino oscillation experiment, the status of LBNE, and the transition to an international collaboration at LBNF.

  15. Testing nonstandard neutrino matter interactions in atmospheric neutrino propagation

    NASA Astrophysics Data System (ADS)

    Chatterjee, Animesh; Mehta, Poonam; Choudhury, Debajyoti; Gandhi, Raj

    2016-05-01

    We study the effects of nonstandard interactions on the oscillation pattern of atmospheric neutrinos. We use neutrino oscillograms as our main tool to infer the role of nonstandard interactions (NSI) parameters at the probability level in the energy range, E ∈[1 ,20 ] GeV and zenith angle range, cos θ ∈[-1 ,0 ] . We compute the event rates for atmospheric neutrino events in presence of NSI parameters in the energy range E ∈[1 ,10 ] GeV for two different detector configurations—a magnetized iron calorimeter and an unmagnetized liquid argon time projection chamber which have different sensitivities to NSI parameters due to their complementary characteristics.

  16. Diffuse supernova neutrinos: oscillation effects, stellar cooling and progenitor mass dependence

    SciTech Connect

    Lunardini, Cecilia; Tamborra, Irene E-mail: tamborra@mpp.mpg.de

    2012-07-01

    We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5–10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10% or less, small compared to the uncertainty of at least 25% of the normalization of the supernova rate. Therefore, assuming that the sign of the neutrino mass hierarchy will be determined within the next decade, the future detection of the DSNB will deliver approximate information on the MSW-oscillated neutrino spectra. With a reliable model for neutrino emission, its detection will be a powerful instrument to provide complementary information on the star formation rate and for learning about stellar physics.

  17. Probing the Dark Matter mass and nature with neutrinos

    SciTech Connect

    Blennow, Mattias; Carrigan, Marcus; Martinez, Enrique Fernandez E-mail: carri@kth.se

    2013-06-01

    We study the possible indirect neutrino signal from dark matter annihilations inside the Sun's core for relatively light dark matter masses in the O(10) GeV range. Due to their excellent energy reconstruction capabilities, we focus on the detection of this flux in liquid argon or magnetized iron calorimeter detectors, proposed for the next generation of far detectors of neutrino oscillation experiments and neutrino telescopes. The aim of the study is to probe the ability of these detectors to determine fundamental properties of the dark matter nature such as its mass or its relative annihilation branching fractions to different channels. We find that these detectors will be able to accurately measure the dark matter mass as long as the dark matter annihilations have a significant branching into the neutrino or at least the τ channel. We have also discovered degeneracies between different dark matter masses and annihilation channels, where a hard τ channel spectrum for a lower dark matter mass may mimic that of a softer quark channel spectrum for a larger dark matter mass. Finally, we discuss the sensitivity of the detectors to the different branching ratios and find that it is between one and two orders of magnitude better than the current bounds from those coming from analysis of Super-Kamiokande data.

  18. Neutrino oscillations and the Landau-Zener formula

    SciTech Connect

    Kim, C.W.; Sze, W.K.; Nussinov, S.

    1987-06-15

    We discuss solar-neutrino oscillations and the Landau-Zener probability using a heuristic picture in analogy with an electron spin in a time-dependent magnetic field. The extreme nonadiabatic resonant oscillation is also briefly investigated.

  19. New Ambiguity in Probing C P Violation in Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Miranda, O. G.; Tórtola, M.; Valle, J. W. F.

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new C P phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δC P, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δC P.

  20. Future long-baseline neutrino oscillations: View from Asia

    SciTech Connect

    Hayato, Yoshinari

    2015-07-15

    Accelerator based long-baseline neutrino oscillation experiments have been playing important roles in revealing the nature of neutrinos. However, it turned out that the current experiments are not sufficient to study two major remaining problems, the CP violation in the lepton sector and the mass hierarchy of neutrinos. Therefore, several new experiments have been proposed. Among of them, two accelerator based long-baseline neutrino oscillation experiments, the J-PARC neutrino beam and Hyper-Kamiokande, and MOMENT, have been proposed in Asia. These two projects are reviewed in this article.

  1. N-mode coherence in collective neutrino oscillations

    SciTech Connect

    Raffelt, Georg G.

    2011-05-15

    We study two-flavor neutrino oscillations in a homogeneous and isotropic ensemble under the influence of neutrino-neutrino interactions. For any density there exist forms of collective oscillations that show self-maintained coherence. They can be classified by a number N of linearly independent functions that describe all neutrino modes as linear superpositions. What is more, the dynamics is equivalent to another ensemble with the same effective density, consisting of N modes with discrete energies E{sub i} with i=1,...,N. We use this equivalence to derive the analytic solution for two-mode (bimodal) coherence, relevant for spectral-split formation in supernova neutrinos.

  2. New Ambiguity in Probing CP Violation in Neutrino Oscillations.

    PubMed

    Miranda, O G; Tórtola, M; Valle, J W F

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new CP phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δ_{CP}, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δ_{CP}. PMID:27541461

  3. Neutrino oscillations: Quantum mechanics vs. quantum field theory

    SciTech Connect

    Akhmedov, Evgeny Kh.; Kopp, Joachim

    2010-01-01

    A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between them. In particular, we derive expressions for the QM neutrino wave packets from QFT and relate the free parameters of the QM framework, in particular the effective momentum uncertainty of the neutrino state, to the more fundamental parameters of the QFT approach. We include in our discussion the possibilities that some of the neutrino's interaction partners are not detected, that the neutrino is produced in the decay of an unstable parent particle, and that the overlap of the wave packets of the particles involved in the neutrino production (or detection) process is not maximal. Finally, we demonstrate how the properly normalized oscillation probabilities can be obtained in the QFT framework without an ad hoc normalization procedure employed in the QM approach.

  4. Analytical description of quasivacuum oscillations of solar neutrinos

    NASA Astrophysics Data System (ADS)

    Lisi, E.; Marrone, A.; Montanino, D.; Palazzo, A.; Petcov, S. T.

    2001-05-01

    We propose a simple prescription to calculate the solar neutrino survival probability Pee in the quasivacuum oscillation (QVO) regime. Such a prescription is obtained by matching perturbative and exact analytical results, which effectively take into account the density distribution in the Sun as provided by the standard solar model. The resulting analytical recipe for the calculation of Pee is shown to reach its highest accuracy (\\|ΔPee\\|<=2.6×10-2 in the whole QVO range) when the familiar prescription of choosing the solar density scale parameter r0 at the Mikheyev-Smirnov-Wolfenstein (MSW) resonance point is replaced by a new one, namely, when r0 is chosen at the point of ``maximal violation of adiabaticity'' (MVA) along the neutrino trajectory in the Sun. The MVA prescription admits a smooth transition from the QVO regime to the MSW transition one. We discuss in detail the phase acquired by neutrinos in the Sun, and show that it might be of relevance for the studies of relatively short time scale variations of the fluxes of the solar ν lines in the future real-time solar neutrino experiments. Finally, we elucidate the role of matter effects in the convective zone of the Sun.

  5. On a theory of neutrino oscillations with entanglement

    SciTech Connect

    Kayser, Boris; Kopp, Joachim; Roberston, R.G.Hamish; Vogel, Petr; /Caltech, Kellogg Lab

    2010-06-01

    We show that the standard expression for the neutrino oscillation length can be confirmed even in theoretical approaches that take into account entanglement between the neutrino and its interaction partners. We show this in particular for the formalism developed in arXiv:1004.1847. Finally, we shed some light on the question why plane-wave approaches to the neutrino oscillation problem can yield the correct result for the oscillation length even though they do not explicitly account for the localization of the neutrino source and the detector.

  6. Approach to the propagation of massive neutrinos in dense matter by Wigner functions

    NASA Astrophysics Data System (ADS)

    Sirera Tomas, Miguel

    The problem of massive neutrinos comes from Grant Unification Theories but also from the so called Neutrino Solar Puzzle. The solution of this puzzle seems to be in the neutrinos physics and to need that the neutrinos are particles with mass. The possible mass of the neutrinos is not only important for Solar Neutrinos but also in other astrophysical environments such as Supernovae, Neutron Stars or The Early Universe. If the neutrinos are particles with mass, or at least one of their generations, oscillations are produced in both vacuum and matter. The oscillation in matter could cause the so called MSW effect, that transforms a neutrino flavour to another. The problem of the propagation of neutrinos in matter has been dealt with by many authors who have usually solved the covariant motion equations, and sometimes by Green Functions. In this work, this has been done using statistical techniques by Wigner Functions, which do not only allow us to study the propagation ways but also to know the behavior of the neutrinos field in equilibrium. On the other hand, the astrophysical systems, that we have commented above, yield a great amount of neutrinos which spread through them and are finally emitted to space, and so it is important to have a transport equation that explain how a neutrinos distribution is spread which is not in equilibrium. It is possible to achieve this equation by motion equations of the Wigner Functions.

  7. Effects of neutrino oscillations on nucleosynthesis and neutrino signals for an 18 M⊙ supernova model

    NASA Astrophysics Data System (ADS)

    Wu, Meng-Ru; Qian, Yong-Zhong; Martínez-Pinedo, Gabriel; Fischer, Tobias; Huther, Lutz

    2015-03-01

    In this paper, we explore the effects of neutrino flavor oscillations on supernova nucleosynthesis and on the neutrino signals. Our study is based on detailed information about the neutrino spectra and their time evolution from a spherically symmetric supernova model for an 18 M⊙ progenitor. We find that collective neutrino oscillations are not only sensitive to the detailed neutrino energy and angular distributions at emission, but also to the time evolution of both the neutrino spectra and the electron density profile. We apply the results of neutrino oscillations to study the impact on supernova nucleosynthesis and on the neutrino signals from a Galactic supernova. We show that in our supernova model, collective neutrino oscillations enhance the production of rare isotopes 138La and 180Ta but have little impact on the ν p -process nucleosynthesis. In addition, the adiabatic Mikheyev-Smirnov-Wolfenstein flavor transformation, which occurs in the C /O and He shells of the supernova, may affect the production of light nuclei such as 7Li and 11B. For the neutrino signals, we calculate the rate of neutrino events in the Super-Kamiokande detector and in a hypothetical liquid argon detector. Our results suggest the possibility of using the time profiles of the events in both detectors, along with the spectral information of the detected neutrinos, to infer the neutrino mass hierarchy.

  8. Detecting CP violation in a single neutrino oscillation channel at very long baselines

    SciTech Connect

    Latimer, D. C.; Escamilla, J.; Ernst, D. J.

    2007-11-15

    We propose a way of detecting CP violation in a single neutrino oscillation channel at very long baselines (on the order of several thousands of kilometers), given precise knowledge of the smallest mass-squared difference. It is shown that CP violation can be characterized by a shift in L/E of the peak oscillation in the {nu}{sub e}-{nu}{sub {mu}} appearance channel, both in vacuum and in matter. In fact, matter effects enhance the shift at a fixed energy. We consider the case in which sub-GeV neutrinos are measured with varying baseline and also the case of a fixed baseline. For the varied baseline, accurate knowledge of the absolute neutrino flux would not be necessary; however, neutrinos must be distinguishable from antineutrinos. For the fixed baseline, it is shown that CP violation can be distinguished if the mixing angle {theta}{sub 13} were known.

  9. Neutrino signals from dark matter decay

    SciTech Connect

    Covi, Laura; Grefe, Michael; Ibarra, Alejandro; Tran, David E-mail: michael.grefe@desy.de E-mail: david.tran@ph.tum.de

    2010-04-01

    We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the dark matter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and dark matter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different dark matter decay channels.

  10. Global analyses of neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Gonzalez-Garcia, M. C.; Maltoni, Michele; Schwetz, Thomas

    2016-07-01

    We summarize the determination of some neutrino properties from the global analysis of solar, atmospheric, reactor, and accelerator neutrino data in the framework of three-neutrino mixing as well as in some extended scenarios such as the mixing with eV-scale sterile neutrinos invoked for the interpretation of the short baseline anomalies, and the presence of non-standard neutrino interactions.

  11. Optical simulation of neutrino oscillations in binary waveguide arrays.

    PubMed

    Marini, Andrea; Longhi, Stefano; Biancalana, Fabio

    2014-10-10

    We theoretically propose and investigate an optical analogue of neutrino oscillations in a pair of vertically displaced binary waveguide arrays with longitudinally modulated effective refractive index. Optical propagation is modeled through coupled-mode equations, which in the continuous limit converge to two coupled Dirac equations for fermionic particles with different mass states, analogously to neutrinos. In addition to simulating neutrino oscillation in the noninteracting regime, our optical setting enables us to explore neutrino interactions in extreme regimes that are expected to play an important role in massive supernova stars. In particular, we predict the quenching of neutrino oscillations and the existence of topological defects, i.e., neutrino solitons, which in our photonic simulator should be observable as excitation of optical gap solitons propagating along the binary arrays at high excitation intensities. PMID:25375692

  12. Active-sterile neutrino oscillations in the early universe with dynamical neutrino asymmetries

    NASA Astrophysics Data System (ADS)

    Saviano, Ninetta

    2013-04-01

    In the last recent years different anomalies observed in short-baseline neutrino oscillation experiments seem to point towards the existence of light sterile neutrinos. These sterile neutrinos can also be produced in the early universe by oscillations of the active neutrinos and can affect different cosmological observables. In order to quantify the abundance of sterile neutrinos, we perform a detailed study of the flavor evolution in (3+1) and (2+1) oscillation schemes, in presence of dynamical primordial neutrino asymmetries L. We find that for |L|≲10-4 eV sterile neutrinos would be completely thermalized creating a tension with the cosmological data. An asymmetry of |L|≳10-3 is then required in order to suppress the sterile production and to reconcile them with cosmology.

  13. Three flavor oscillation analysis of atmospheric neutrinos in Super-Kamiokande

    NASA Astrophysics Data System (ADS)

    Wendell, Roger Alexandre

    In this dissertation atmospheric neutrino data from the 50 kiloton water-Cherenkov detector, Super-Kamiokande, are studied in the context of neutrino oscillations. Data presented here are taken from the 1489-day SK-I and 803-day SK-II exposures. Super-Kamiokande's atmospheric neutrino sample exhibits a zenith angle dependent deficit of numu interactions which is well explained by maximal two-flavor numu↔nutau oscillations. This analysis extends the two-flavor framework to include all active neutrino flavors and searches for sub-dominant oscillation effects in the oscillations of atmospheric neutrinos. If the last unknown mixing angle, theta 13, is non-zero there is enhancement (suppression) of the nu mu→nue three-flavor oscillation probability in matter for several GeV neutrinos with long baselines under the normal (inverted) mass hierarchy. At Super-Kamiokande this effect would manifest itself as an increase in the high energy nue event rate coming from below the detector. Searching the SK-I, SK-II and their combined data finds no evidence of a rate excess and yields a best fit to theta 13 of zero assuming either hierarchy. This extended analysis remains consistent with the current knowledge of two-flavor atmospheric mixing finding best fit values sin2theta23 = 0.5 and Delta m2 = 2.6 x 10-3 eV2. No preference for either the normal or inverted mass hierarchy is found in the data.

  14. Future long-baseline neutrino oscillations: View from Europe

    NASA Astrophysics Data System (ADS)

    Patzak, T.

    2015-07-01

    Since about a decade the european physics community interested in neutrino and neutrino-astrophysics develops a plan to conceive the next generation large underground neutrino observatory. Recently, the LAGUNA-LBNO collaboration made the outcome of the FP7 design study public which shows a clear path for the realization of such experiment. In this paper the LAGUNA and LAGUNA-LBNO Design studies, resulting in a proposal for the LBNO experiment, will be discussed. The author will focus on the long baseline neutrino oscillation search, especially on the potential to discover the neutrino mass ordering and the search for CP violation in the lepton sector.

  15. Future long-baseline neutrino oscillations: View from Europe

    SciTech Connect

    Patzak, T.

    2015-07-15

    Since about a decade the european physics community interested in neutrino and neutrino-astrophysics develops a plan to conceive the next generation large underground neutrino observatory. Recently, the LAGUNA-LBNO collaboration made the outcome of the FP7 design study public which shows a clear path for the realization of such experiment. In this paper the LAGUNA and LAGUNA-LBNO Design studies, resulting in a proposal for the LBNO experiment, will be discussed. The author will focus on the long baseline neutrino oscillation search, especially on the potential to discover the neutrino mass ordering and the search for CP violation in the lepton sector.

  16. Solar oscillation frequency and solar neutrino predictions

    SciTech Connect

    Cox, A.N.

    1990-07-05

    The light and velocity variations of the Sun and solar-like stars are unique among intrinsic variable stars. Unlike all other standard classes, such as Cepheids, B stars, and white dwarfs, the pulsation driving is caused by coupling with the acoustic noise in the upper convection zone. Each global pulsation mode is just another degree of freedom for the turbulent convection, and energy is shared equally between these g{sup {minus}}-modes and the solar oscillation modes. This driving and damping, together with the normal stellar pulsation mechanisms produce extremely low amplitude solar oscillations. Actually, the surface layer radiative damping is strong, and the varying oscillation mode amplitudes manifest the stochastic convection driving and the steady damping. Thus stability calculations for solar-like pulsations are difficult and mostly inconclusive, but calculations of pulsation periods are as straightforward as for all the other classes of intrinsic variable stars. The issue that is important for the Sun is its internal structure, because the mass, radius, and luminosity are extremely well known. Conventionally, we need the pulsation constants for each of millions of modes. Unknown parameters for constructing solar models are the composition and its material pressure, energy, and opacity, as well as the convection mixing length. We treat the nuclear energy and neutrino production formulas as sufficiently well known. The presence of weakly interacting massive particles (WIMPs) orbiting the solar center affects the predicted oscillation frequencies so that they do not agree with observations as well as those for models without WIMPs. 34 refs., 4 figs.

  17. Constraints on neutrino-dark matter interactions from cosmic microwave background and large scale structure data

    SciTech Connect

    Serra, Paolo; Cooray, Asantha; Zalamea, Federico; Mangano, Gianpiero; Melchiorri, Alessandro

    2010-02-15

    We update a previous investigation of cosmological effects of a nonstandard interaction between neutrinos and dark matter. Parametrizing the elastic-scattering cross section between the two species as a function of the temperature of the Universe, the resulting neutrino-dark matter fluid has a nonzero pressure, which determines diffusion-damped oscillations in the matter power spectrum similar to the acoustic oscillations generated by the photon-baryon fluid. Using cosmic microwave background data in combination with large scale structure experiment results, we then put constraints on the fraction of the interacting dark matter component as well as on the corresponding opacity.

  18. Neutrinos from Inert Doublet dark matter

    SciTech Connect

    Andreas, Sarah; Tytgat, Michel H.G.; Swillens, Quentin E-mail: mtytgat@ulb.ac.be

    2009-04-15

    We investigate the signatures of neutrinos produced in the annihilation of WIMP dark matter in the Earth, the Sun and at the Galactic centre within the framework of the Inert Doublet Model and extensions. We consider a dark matter candidate, that we take to be one of the neutral components of an extra Higgs doublet, in three distinct mass ranges, which have all been shown previously to be consistent with both WMAP abundance and direct detection experiments exclusion limits. Specifically, we consider a light WIMP with mass between 4 and 8 GeV (low), a WIMP with mass around 60-70 GeV (middle) and a heavy WIMP with mass above 500 GeV (high). In the first case, we show that capture in the Sun may be constrained using Super-Kamiokande data. In the last two cases, we argue that indirect detection through neutrinos is challenging but not altogether excluded. For middle masses, we try to make the most benefit of the proximity of the so-called 'iron resonance' that might enhance the capture of the dark matter candidate by the Earth. The signal from the Earth is further enhanced if light right-handed Majorana neutrinos are introduced, in which case the scalar dark matter candidate may annihilate into pairs of mono-energetic neutrinos. In the case of high masses, detection of neutrinos from the Galactic centre might be possible, provided the dark matter abundance is substantially boosted.

  19. Future Long-Baseline Neutrino Oscillations: View from North America

    SciTech Connect

    Wilson, R. J.

    2015-06-01

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE), that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  20. Future long-baseline neutrino oscillations: View from North America

    SciTech Connect

    Wilson, Robert J.

    2015-07-15

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE) that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  1. Future long-baseline neutrino oscillations: View from North America

    NASA Astrophysics Data System (ADS)

    Wilson, Robert J.

    2015-07-01

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE) that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  2. Neutrino oscillation studies with IceCube-DeepCore

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Abraham, K.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Ansseau, I.; Archinger, M.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Beiser, E.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Fuchs, T.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Gier, D.; Gladstone, L.; Glagla, M.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Góra, D.; Grant, D.; Griffith, Z.; Groß, A.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, B.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Holzapfel, K.; Homeier, A.; Hoshina, K.; Huang, F.; Huber, M.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Jurkovic, M.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kiryluk, J.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, G.; Kroll, M.; Krückl, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leuner, J.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mandelartz, M.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Middell, E.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Richter, S.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Sabbatini, L.; Sander, H.-G.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Schatto, K.; Schimp, M.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schulte, L.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stahlberg, M.; Stamatikos, M.; Stanev, T.; Stasik, A.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vallecorsa, S.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Santen, J.; Veenkamp, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.

    2016-07-01

    IceCube, a gigaton-scale neutrino detector located at the South Pole, was primarily designed to search for astrophysical neutrinos with energies of PeV and higher. This goal has been achieved with the detection of the highest energy neutrinos to date. At the other end of the energy spectrum, the DeepCore extension lowers the energy threshold of the detector to approximately 10 GeV and opens the door for oscillation studies using atmospheric neutrinos. An analysis of the disappearance of these neutrinos has been completed, with the results produced being complementary with dedicated oscillation experiments. Following a review of the detector principle and performance, the method used to make these calculations, as well as the results, is detailed. Finally, the future prospects of IceCube-DeepCore and the next generation of neutrino experiments at the South Pole (IceCube-Gen2, specifically the PINGU sub-detector) are briefly discussed.

  3. Neutrino signature of Inert Doublet Dark Matter

    NASA Astrophysics Data System (ADS)

    Andreas, Sarah

    2010-06-01

    In the framework of the Inert Doublet Model and extensions, the signature of neutrinos from dark matter annihilation in the Earth, the Sun and at the Galactic centre is presented. The model contains an extra Higgs doublet, a neutral component of which is chosen as dark matter candidate. There are three distinct mass ranges for which consistency both with WMAP abundance and direct searches can be obtained: a low (4-8 GeV), a middle (60-70 GeV) and a high (500-1500 GeV) WIMP mass range. The first case is of interest as we showed that the model can at the same time give the correct WMAP abundance and account for the positive DAMA results without contradicting other direct searches. We present how capture in the Sun can further constrain this scenario using Super-Kamiokande data. Indirect detection through neutrinos is challenging for the middle and high mass ranges. For the former, the presence of the so-called `iron resonance' gives rise to larger neutrino fluxes for WIMP masses around 60-70 GeV since capture by the Earth is enhanced. The addition of light right-handed Majo-rana neutrinos to the particle content of the model further increases the signal since it opens a direct annihilation channel into mono-energetic neutrinos. Neutrinos from the Galactic centre might be detected for heavy WIMPs if the dark matter density at the Galactic centre is substantially boosted.

  4. The Effects of Collective Neutrino Oscillations on Supernova Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Seadrow, Shaquann; Frohlich, C.; Duan, H.; Friedland, A.; McLaughlin, G.; Keohane, J. W.

    2014-01-01

    A core-collapse supernova originates from the implosion of the electron degenerate core inside a massive star. Runaway electron capture produces on the order of 1057 neutrinos containing about 1053 erg of energy in total. While the vast majority of neutrinos are eventually released, during the first few seconds these neutrinos drive both the dynamics, and likewise the nucleosynthesis, inside the supernova. Recently, our understanding of oscillations among the different flavors of neutrinos (electron, muon, and tau) has significantly improved, allowing us to ask if neutrino flavor change has a significant effect on nucleosynthesis in a core-collapse supernova. To investigate the effects of collective neutrino flavor oscillations, we use the hydrodynamic conditions from a spherically-symmetrical model of the implosion, bounce, and explosion of the 1.4 solar mass core that is inside an 8.8 solar mass star (Huedepohl et al. 2009). We select 20 mass tracers in the ejecta, varying in initial radii, and follow these trajectories for the first 9 seconds following bounce. We include these trajectories into a nuclear reaction network in order to calculate the detailed nucleosynthesis. We use three sets of neutrino reaction rates, all of which are calculated consistently with the conditions in the supernova model: (i) no collective flavor oscillations, (ii) collective oscillations for normal neutrino mass hierarchy, and (iii) collective oscillations for inverted neutrino mass hierarchy. We calculate the detailed nucleosynthesis for each trajectory for all three sets of neutrino rates. We find that the inclusion of collective oscillations (ii or iii) significantly increases the free neutron abundance; however, we obtain similar results regardless of which hierarchy is used. The increase in free neutrons also increases the subsequent rate of neutron capture, but has only a small effect on the predicted final abundances. This work was performed as part of North Carolina State

  5. NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER

    SciTech Connect

    Bacca, S.; Hally, K.; Liebendoerfer, M.; Perego, A.; Pethick, C. J.; Schwenk, A.

    2012-10-10

    We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

  6. Particle production with left-right neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Enomoto, Seishi; Matsuda, Tomohiro

    2016-03-01

    When the Higgs field starts oscillation after Higgs inflation, gauge bosons are produced nonperturbatively near the enhanced symmetry point (ESP). Just after the particle production, when the Higgs field is going away from the ESP, these gauge bosons gain mass and decay or annihilate into Standard Model (SM) fermions. Left-handed neutrinos can be generated in that way. If one assumes the seesaw mechanism, the mass matrix of a pair of left- and right-handed neutrinos is nondiagonal. Although their mixing in the mass eigenstates is negligible in the true vacuum, it could be significant near the edge of the Higgs oscillation, where the off-diagonal component is large. Therefore, the left-handed neutrinos generated from the gauge bosons can start neutrino oscillation between the right-handed neutrinos. We study the particle production when such left-right (L-R) neutrino oscillation is significant. For a working example, the nonthermal leptogenesis scenario after Higgs inflation is examined, which cannot be realized without the L-R neutrino oscillation. The same mechanism could be applied to other singlet particles whose abundance has been neglected.

  7. Pseudoscalar—sterile neutrino interactions: reconciling the cosmos with neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Archidiacono, Maria; Gariazzo, Stefano; Giunti, Carlo; Hannestad, Steen; Hansen, Rasmus; Laveder, Marco; Tram, Thomas

    2016-08-01

    The Short BaseLine (SBL) neutrino oscillation anomalies hint at the presence of a sterile neutrino with a mass of around 1 eV. However, such a neutrino is incompatible with cosmological data, in particular observations of the Cosmic Microwave Background (CMB) anisotropies. However, this conclusion can change by invoking new physics. One possibility is to introduce a secret interaction in the sterile neutrino sector mediated by a light pseudoscalar. In this pseudoscalar model, CMB data prefer a sterile neutrino mass that is fully compatible with the mass ranges suggested by SBL anomalies. In addition, this model predicts a value of the Hubble parameter which is completely consistent with local measurements.

  8. New results for muon neutrino to electron neutrino oscillations in the MINOS experiment

    SciTech Connect

    Evans, Justin; Whitehead, Lisa; /Brookhaven

    2010-01-01

    MINOS is a long-baseline neutrino oscillation experiment situated along Fermilab's high-intensity NuMI neutrino beam. MINOS has completed an updated search for muon neutrino to electron neutrino transitions, observation of which would indicate a non-zero value for the neutrino mixing angle {theta}{sub 13}. The present 7 x 10{sup 20} protons-on-target data set represents more than double the exposure used in the previous analysis. The new result and its implications are presented.

  9. Radiative neutrino mass generation from WIMP dark matter

    NASA Astrophysics Data System (ADS)

    Lineros, Roberto A.

    2016-05-01

    The minimal seesaw extension of the Standard Model requires two electroweak singlet fermions in order to accommodate the neutrino oscillation parameters at tree level. Here we consider a next to minimal extension where light neutrino masses are generated radiatively by two electroweak fermions: one singlet and one triplet under SU(2). These should be odd under a parity symmetry and their mixing gives rise to a stable weakly interactive massive particle dark matter candidate. For mass in the GeV-TeV range, it reproduces the correct relic density, and provides an observable signal in nuclear recoil direct detection experiments. The fermion triplet component of the dark matter has gauge interactions, making it also detectable at present and near future collider experiments.

  10. Self-induced parametric resonance in collective neutrino oscillations

    SciTech Connect

    Raffelt, Georg G.

    2008-12-15

    We identify a generic new form of collective flavor oscillations in dense neutrino gases that amounts to a self-induced parametric resonance. It occurs in a homogeneous and isotropic ensemble when a range of neutrino modes is prepared in a different flavor than the neighboring modes with lower and higher energies. The flavor content of the intermediate spectral part librates relative to the other parts with a frequency corresponding to a typical {delta}m{sup 2}/2E. This libration persists in the limit of an arbitrarily large neutrino density where one would have expected synchronized flavor oscillations.

  11. SOX: Short distance neutrino Oscillations with BoreXino

    NASA Astrophysics Data System (ADS)

    Bellini, G.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chavarria, A.; Chepurnov, A.; D'Angelo, D.; Davini, S.; Derbin, A.; Etenko, A.; Fernandes, G.; Fomenko, K.; Franco, D.; Galbiati, C.; Ghiano, C.; Göger-Neff, M.; Goretti, A.; Hagner, C.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Kobychev, V.; Korablev, D.; Korga, G.; Krasnicky, D.; Kryn, D.; Laubenstein, M.; Link, J. M.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Mosteiro, P.; Muratova, V.; Oberauer, L.; Obolensky, M.; Ortica, F.; Otis, K.; Pallavicini, M.; Pantic, E.; Papp, L.; Perasso, S.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Rossi, N.; Saldanha, R.; Salvo, C.; Schönert, S.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Unzhakov, E.; Vogelaar, R. B.; Wang, H.; Wojcik, M.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuzel, G.

    2013-08-01

    The very low radioactive background of the Borexino detector, its large size, and the well proved capability to detect both low energy electron neutrinos and antineutrinos make an ideal case for the study of short distance neutrino oscillations with artificial sources at Gran Sasso. This paper describes the possible layouts of 51Cr ( ν e ) and 144Ce-144Pr source experiments in Borexino and shows the expected sensitivity to eV mass sterile neutrinos for three possible different phases of the experiment. Expected results on neutrino magnetic moment, electroweak mixing angle, and couplings to axial and vector currents are shown too.

  12. Solar neutrino experiments and a test for neutrino oscillations with radioactive sources

    SciTech Connect

    Cleveland, B.T.; Davis, R. Jr.; Rowley, J.K.

    1980-01-01

    The results of the Brookhaven solar neutrino experiment are given and compared to the most recent standard solar model calculations. The observations are about a factor of 4 below theoretical expectations. In view of the uncertainties involved in the theoretical models of the sun, the discrepancy is not considered to be evidence for neutrino oscillations. The status of the development of a gallium solar neutrino detector is described. Radiochemical neutrino detectors can be used to search for ..nu../sub e/ oscillations by using megacurie sources of monoenergetic neutrinos like /sup 65/Zn. A quantitative evaluation of possible experiments using the Brookhaven chlorine solar neutrino detector and a gallium detector is given. 6 figures, 3 tables.

  13. Neutrino Oscillation Parameter Sensitivity in Future Long-Baseline Experiments

    SciTech Connect

    Bass, Matthew

    2014-01-01

    The study of neutrino interactions and propagation has produced evidence for physics beyond the standard model and promises to continue to shed light on rare phenomena. Since the discovery of neutrino oscillations in the late 1990s there have been rapid advances in establishing the three flavor paradigm of neutrino oscillations. The 2012 discovery of a large value for the last unmeasured missing angle has opened the way for future experiments to search for charge-parity symmetry violation in the lepton sector. This thesis presents an analysis of the future sensitivity to neutrino oscillations in the three flavor paradigm for the T2K, NO A, LBNE, and T2HK experiments. The theory of the three flavor paradigm is explained and the methods to use these theoretical predictions to design long baseline neutrino experiments are described. The sensitivity to the oscillation parameters for each experiment is presented with a particular focus on the search for CP violation and the measurement of the neutrino mass hierarchy. The variations of these sensitivities with statistical considerations and experimental design optimizations taken into account are explored. The effects of systematic uncertainties in the neutrino flux, interaction, and detection predictions are also considered by incorporating more advanced simulations inputs from the LBNE experiment.

  14. Basic oscillation measurables in the neutrino pair beam

    NASA Astrophysics Data System (ADS)

    Asaka, T.; Tanaka, M.; Yoshimura, M.

    2016-09-01

    It was recently shown that the neutrino-pair emission may occur with large rates, their energy being extended to GeV region, if appropriate heavy ions are circulated in a quantum state of mixture. In the present work it is further demonstrated that the vector current contribution of neutrino interaction with electrons in ion, not necessarily suppressed in high atomic number ions, gives rise to the oscillating component, even when a single neutrino is detected alone. On the other hand, the single neutrino detection in Z-boson decay does not show the oscillating component, as known for some time. CP violation measurements in the neutrino pair beam may become a possibility, along with determination of mass hierarchical patterns.

  15. Neutrino oscillations and uncertainty in the solar model

    NASA Astrophysics Data System (ADS)

    Dearborn, D. S.; Fuller, G. M.

    1989-06-01

    The Mikheyev-Smirnov-Wolfenstein (MSW) resonant neutrino oscillation mechanism is investigated for the Sun using a detailed numerical solar model and a modified version of the Parke-Walker technique for following the neutrino phases through the oscillation resonance. We present overall solar-neutrino spectra and the associated expected neutrino count rates for the 37Cl, 71Ga, and Kamiokande detectors for ranges of masses and vacuum mixing angles for two neutrino species. We also investigate the effects of uncertainties in the solar model. In particular, we examine the effect of opacity changes on the expected solar-neutrino spectrum and resulting parameter space for the MSW mechanism. We find that plausible uncertainties in the standard solar model, and in particular the opacity, translate into significant expansion in the constraints on neutrino masses and vacuum mixing angles from neutrino experiments. It is shown, however, that forthcoming results from the Kamiokande solar-neutrino experiment could put stringent constraints on even the expanded MSW parameter space.

  16. B-Meson and Neutrino Oscillation: A Unified Treatment

    SciTech Connect

    Kayser, Boris; /Fermilab

    2011-10-01

    We present a unified treatment of the quantum mechanics of B-factory and neutrino oscillation experiments. While our approach obtains the usual phenomenological predictions for these experiments, it does so without having to invoke perplexing Einstein-Podolsky-Rosen correlations or non-intuitive kinematical assumptions. The quantum mechanics of mixing during propagation is at the heart of both B-factory and neutrino oscillation experiments. In this paper, we will treat both these experiments in the same way. Our treatment has several advantages. In dealing with the B-factory experiments, it avoids having to invoke real but nonetheless puzzling Einstein-Podolsky-Rosen correlations. In dealing with neutrino oscillation, our approach avoids the non-intuitive assumption that all the interfering neutrino mass eigenstates in a beam have the same energy.

  17. Barr-Freire-Zee mechanism for the hydrogen-ionizing decaying neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Tommasini, Daniele

    1992-12-01

    We consider the scenario of the hydrogen-ionizing decaying neutrino dark matter, advocated by Sciama to solve several ionization problems in astrophysics and cosmology. We show that dangerously large neutrino oscillations are expected in general in the particle physics models introduced to provide the required neutrino masses and dark matter decay lifetime. However, the implementation of a mechanism recently discovered by Barr, Freire and Zee, allows to realize this scenario free of large neutrino oscillations. Furthermore, in this case a mass scale for the light neutrinos, which can be naturally the MSW solar neutrino scale ~ 10-3 eV, is automatically associated to the value ~ 1023 s of the dark matter decay lifetime, needed to solve the ionization problems. A realization of the mechanism in the supersymmetric standard model with broken R-parity is then considered as an example. In that case, the heavy neutrino providing the dark matter is made up mainly by the standard muon neutrino νμ.

  18. Sterile neutrinos as subdominant warm dark matter

    SciTech Connect

    Palazzo, A.; Cumberbatch, D.; Slosar, A.; Silk, J.

    2007-11-15

    In light of recent findings which seem to disfavor a scenario with (warm) dark matter entirely constituted of sterile neutrinos produced via the Dodelson-Widrow mechanism, we investigate the constraints attainable for this mechanism by relaxing the usual hypothesis that the relic neutrino abundance must necessarily account for all of the dark matter. We first study how to reinterpret the limits attainable from x-ray nondetection and Lyman-{alpha} forest measurements in the case that sterile neutrinos constitute only a fraction f{sub s} of the total amount of dark matter. Then, assuming that sterile neutrinos are generated in the early universe solely through the Dodelson-Widrow mechanism, we show how the x-ray and Lyman-{alpha} results jointly constrain the mass-mixing parameters governing their production. Furthermore, we show how the same data allow us to set a robust upper limit f{sub s} < or approx. 0.7 at the 2{sigma} level, rejecting the case of dominant dark matter (f{sub s}=1) at the {approx}3{sigma} level.

  19. Realistic Sterile Neutrino Dark Matter with KeV Mass does not Contradict Cosmological Bounds

    SciTech Connect

    Boyarsky, Alexey; Lesgourgues, Julien; Ruchayskiy, Oleg

    2009-05-22

    Previous fits of sterile neutrino dark matter (DM) models to cosmological data ruled out masses smaller than {approx}8 keV, assuming a production mechanism that is not the best motivated from a particle physics point of view. Here we focus on a realistic extension of the standard model with three sterile neutrinos, consistent with neutrino oscillation data and baryogenesis, with the lightest sterile neutrino being the DM particle. We show that for each mass {>=}2 keV there exists at least one model accounting for 100% of DM and consistent with Lyman-{alpha} and other cosmological, astrophysical, and particle physics data.

  20. The analysis of solar models: Neutrinos and oscillations

    NASA Technical Reports Server (NTRS)

    Ulrich, R. K.; Rhodes, E. J., Jr.; Tomczyk, S.; Dumont, P. J.; Brunish, W. M.

    1983-01-01

    Tests of solar neutrino flux and solar oscillation frequencies were used to assess standard stellar structure theory. Standard and non-standard solar models are enumerated and discussed. The field of solar seismology, wherein the solar interior is studied from the measurement of solar oscillations, is introduced.

  1. Landau-Zener approximations for resonant neutrino oscillations

    SciTech Connect

    Whisnant, K.

    1988-07-15

    A simple method for calculating the effects of resonant neutrino oscillations using Landau-Zener approximations is presented. For any given set of oscillation parameters, the method is to use the Landau-Zener approximation which works best in that region.

  2. Aspects of neutrino oscillation in alternative gravity theories

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sumanta

    2015-10-01

    Neutrino spin and flavour oscillation in curved spacetime have been studied for the most general static spherically symmetric configuration. Having exploited the spherical symmetry we have confined ourselves to the equatorial plane in order to determine the spin and flavour oscillation frequency in this general set-up. Using the symmetry properties we have derived spin oscillation frequency for neutrino moving along a geodesic or in a circular orbit. Starting from the expression of neutrino spin oscillation frequency we have shown that even in this general context, in high energy limit the spin oscillation frequency for neutrino moving along circular orbit vanishes. We have verified previous results along this line by transforming to Schwarzschild coordinates under appropriate limit. This finally lends itself to the probability of neutrino helicity flip which turns out to be non-zero. While for neutrino flavour oscillation we have derived general results for oscillation phase, which subsequently have been applied to three different gravity theories. One, of them appears as low-energy approximation to string theory, where we have an additional field, namely, dilaton field coupled to Maxwell field tensor. This yields a realization of Reissner-Nordström solution in string theory at low-energy. Next one corresponds to generalization of Schwarzschild solution by introduction of quadratic curvature terms of all possible form to the Einstein-Hilbert action. Finally, we have also discussed regular black hole solutions. In all these cases the flavour oscillation probabilities can be determined for solar neutrinos and thus can be used to put bounds on the parameters of these gravity theories. While for spin oscillation probability, we have considered two cases, Gauss-Bonnet term added to the Einstein-Hilbert action and the f(R) gravity theory. In both these cases we could impose bounds on the parameters which are consistent with previous considerations. In a nutshell, in

  3. Measurement of atmospheric neutrino oscillations with IceCube.

    PubMed

    Aartsen, M G; Abbasi, R; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Becker Tjus, J; Becker, K-H; Bell, M; Benabderrahmane, M L; Benzvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H-P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Cruz Silva, A H; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Desiati, P; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Haj Ismail, A; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kislat, F; Kläs, J; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Mészáros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Palazzo, A; Paul, L; Pepper, J A; Pérez de los Heros, C; Pfendner, C; Pieloth, D; Pinat, E; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Wasserman, R; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-08-23

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored. PMID:24010427

  4. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect

    Kajino, Toshitaka

    2012-11-20

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like {sup 7}Li, {sup 11}B, {sup 138}La, {sup 180}Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, {theta}{sub 13} and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process {sup 11}B and {sup 7}Li encapsulated in the grains. Combining the recent experimental constraints on {theta}{sub 13}, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  5. A measurement of neutrino oscillations with muon neutrinos in the MINOS experiment

    SciTech Connect

    Coleman, Stephen James

    2011-05-01

    Experimental evidence has established that neutrino flavor states evolve over time. A neutrino of a particular flavor that travels some distance can be detected in a different neutrino flavor state. The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline experiment that is designed to study this phenomenon, called neutrino oscillations. MINOS is based at Fermilab near Chicago, IL, and consists of two detectors: the Near Detector located at Fermilab, and the Far Detector, which is located in an old iron mine in Soudan, MN. Both detectors are exposed to a beam of muon neutrinos from the NuMI beamline, and MINOS measures the fraction of muon neutrinos that disappear after traveling the 734 km between the two detectors. One can measure the atmospheric neutrino mass splitting and mixing angle by observing the energy-dependence of this muon neutrino disappearance. MINOS has made several prior measurements of these parameters. Here I describe recently-developed techniques used to enhance our sensitivity to the oscillation parameters, and I present the results obtained when they are applied to a dataset that is twice as large as has been previously analyzed. We measure the mass splitting Δm232 = (2.32-0.08+0.12) x 10-3 eV2/c4 and the mixing angle sin2(2θ32) > 0.90 at 90% C.L. These results comprise the world's best measurement of the atmospheric neutrino mass splitting. Alternative disappearance models are also tested. The neutrino decay hypothesis is disfavored at 7.2σ and the neutrino quantum decoherence hypothesis is disfavored at 9.0σ.

  6. The effect of short-baseline neutrino oscillations on LBNE

    SciTech Connect

    Louis, William C.

    2015-10-15

    Short-baseline neutrino oscillations can have a relatively big effect on long-baseline oscillations, due to the cross terms that arise from multiple mass scales. The existing short-baseline anomalies suggest that short-baseline oscillations can affect the ν{sub μ} → ν{sub e} appearance probabilities by up to 20-40%, depending on the values of the CP-violating parameters.

  7. Neutrino oscillations in a model with a source and detector

    NASA Astrophysics Data System (ADS)

    Kiers, Ken; Weiss, Nathan

    1998-03-01

    We study the oscillations of neutrinos in a model in which the neutrino is coupled to a localized, idealized source and detector. By varying the spatial and temporal resolution of the source and detector we are able to model the full range of source and detector types ranging from coherent to incoherent. We find that this approach is useful in understanding the interface between the quantum mechanical nature of neutrino oscillations on the one hand and the production and detection systems on the other hand. This method can easily be extended to study the oscillations of other particles such as the neutral K and B mesons. We find that this approach gives a reliable way to treat the various ambiguities which arise when one examines the oscillations from a wave packet point of view. We demonstrate that the conventional oscillation formula is correct in the relativistic limit and that several recent claims of an extra factor of 2 in the oscillation length are incorrect. We also demonstrate explicitly that the oscillations of neutrinos which have separated spatially may be ``revived'' by a long coherent measurement.

  8. Flavor distribution of UHE cosmic neutrino oscillations at neutrino telescopes

    NASA Astrophysics Data System (ADS)

    Xing, Zhi-Zhong

    2009-04-01

    If the ultrahigh-energy (UHE) cosmic neutrinos produced from a distant astrophysical source can be measured at a km-size neutrino telescope such as the IceCube or KM3NeT, they will open a new window to understand the nature of flavor mixing and to probe possible new physics. Considering the conventional UHE cosmic neutrino source with the flavor ratio φe:φμ:φτ=1:2:0, I point out two sets of conditions for the flavor democracy φeT:φμT:φτT=1:1:1 to show up at neutrino telescopes: either θ13=0 and θ23=π/4 (CP invariance) or δ=±π/2 and θ23=π/4 (CP violation) in the standard parametrization of the 3×3 neutrino mixing matrix V. Allowing for slight μ-τ symmetry breaking effects characterized by Δ∈[-0.1,+0.1], I find φeT:φμT:φτT=(1-2Δ):(1+Δ):(1+Δ) as a good approximation. Another possibility to constrain Δ is to detect the ν flux of E≈6.3PeV via the Glashow resonance channel νe→W→anything. I also give some brief comments on (1) possible non-unitarity of V in the seesaw framework and its effects on the flavor distribution at neutrino telescopes and (2) a generic description and determination of the cosmic neutrino flavor composition at distant astrophysical sources.

  9. Self-interacting dark matter and sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Tang, Yong

    2016-05-01

    We discuss some possible astrophysical and cosmological connections between dark matter and sterile neutrinos. Both the controversies at small scales for traditional cold dark matter (CDM) and anomalies in neutrino experiments seem to suggest that there might be new self-interactions for dark matter and sterile neutrinos. Surprisingly, if the new interaction also mediates between dark matter and sterile neutrinos, “missing satellite problem” in CDM paradigm can also be solved. On the other hand, light sterile neutrinos with self-interacting can also satisfy the cosmological bounds.

  10. OscSNS: A Precision Short-Baseline Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Louis, William

    2012-03-01

    Short baseline neutrino experiments are consistent with neutrino oscillations at a δm^2 of approximately 1 eV^2, and world neutrino and antineutrino data fit reasonably well to a 3+2 (active+sterile) neutrino oscillation model with CP violation. The OscSNS experiment at ORNL would be able to make precision short-baseline neutrino oscillation measurements and prove that sterile neutrinos exist. The OscSNS experiment will be described and the corresponding neutrino oscillation sensitivities will be discussed.

  11. Diluted equilibrium sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Patwardhan, Amol V.; Fuller, George M.; Kishimoto, Chad T.; Kusenko, Alexander

    2015-11-01

    We present a model where sterile neutrinos with rest masses in the range ˜keV to ˜MeV can be the dark matter and be consistent with all laboratory, cosmological, and large-scale structure, as well as x-ray constraints. These sterile neutrinos are assumed to freeze out of thermal and chemical equilibrium with matter and radiation in the very early Universe, prior to an epoch of prodigious entropy generation ("dilution") from out-of-equilibrium decay of heavy particles. In this work, we consider heavy, entropy-producing particles in the ˜TeV to ˜EeV rest-mass range, possibly associated with new physics at high-energy scales. The process of dilution can give the sterile neutrinos the appropriate relic densities, but it also alters their energy spectra so that they could act like cold dark matter, despite relatively low rest masses as compared to conventional dark matter candidates. Moreover, since the model does not rely on active-sterile mixing for producing the relic density, the mixing angles can be small enough to evade current x-ray or lifetime constraints. Nevertheless, we discuss how future x-ray observations, future lepton number constraints, and future observations and sophisticated simulations of large-scale structure could, in conjunction, provide evidence for this model and/or constrain and probe its parameters.

  12. Nuclear weak interactions, supernova nucleosynthesis and neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Kajino, Toshitaka

    2013-07-01

    We study the nuclear weak response in light-to-heavy mass nuclei and calculate neutrino-nucleus cross sections. We apply these cross sections to the explosive nucleosynthesis in core-collapse supernovae and find that several isotopes of rare elements 7Li, 11B, 138La, 180Ta and several others are predominantly produced by the neutrino-process nucleosynthesis. We discuss how to determine the suitable neutrino spectra of three different flavors and their anti-particles in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. Light-mass nuclei like 7Li and 11B, which are produced in outer He-layer, are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect, while heavy-mass nuclei like 138La, 180Ta and r-process elements, which are produced in the inner O-Ne-Mg layer or the atmosphere of proto-neutron star, are likely to be free from the MSW effect. Using such a different nature of the neutrino-process nucleosynthesis, we study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the unknown neutrino oscillation parameters, θ13 and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process 11B and 7Li encapsulated in the grains. Combining the recent experimental constraints on θ13, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  13. Neutrino spin dynamics in dense matter and electromagnetic field

    NASA Astrophysics Data System (ADS)

    Arbuzova, E. V.; Lobanov, A. E.; Murchikova, E. M.

    2009-01-01

    A complete set of solutions to the Dirac-Pauli equation is derived for a massive neutrino that interacts with dense matter and a strong electromagnetic field. It is shown that these solutions may describe neutrino spin precession.

  14. The Effect of Neutrino Oscillations on Supernova Light Element Synthesis

    SciTech Connect

    Yoshida, Takashi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H.

    2006-07-12

    We investigate light element synthesis through the {nu}-process during supernova explosions considering neutrino oscillations and investigate the dependence of 7Li and 11B yields on neutrino oscillation parameters mass hierarchy and {theta}13. The adopted supernova explosion model for explosive nucleosynthesis corresponds to SN 1987A. The 7Li and 11B yields increase by about factors of 1.9 and 1.3 in the case of normal mass hierarchy and adiabatic 13-mixing resonance compared with the case without neutrino oscillations. In the case of inverted mass hierarchy or nonadiabatic 13-mixing resonance, the increase in 7Li and 11B yields is much smaller. Astronomical observations of 7Li/11B ratio in stars formed in regions strongly affected by prior generations of supernovae would constrain mass hierarchy and the range of {theta}13.

  15. Flavor entanglement in neutrino oscillations in the wave packet description

    NASA Astrophysics Data System (ADS)

    Blasone, Massimo; Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio

    2015-10-01

    The wave packet approach to neutrino oscillations provides an enlightening description of quantum decoherence induced, during propagation, by localization effects. Within this approach, we show that a deeper insight into the dynamical aspects of particle mixing can be obtained if one investigates the behavior of quantum correlations associated to flavor oscillations. By identifying the neutrino three-flavor modes with (suitably defined) three-qubit modes, the exploitation of tools of quantum information theory for mixed states allows a detailed analysis of the dynamical behavior of flavor entanglement during free propagation. This provides further elements leading to a more complete understanding of the phenomenon of neutrino oscillations, and a basis for possible applicative implementations. The analysis is carried out by studying the distribution of the flavor entanglement; to this aim, we perform combined investigations of the behaviors of the two-flavor concurrence and of the logarithmic negativities associated with specific bipartitions of the three flavors.

  16. Neutrino mass hierarchy, vacuum oscillations, and vanishing |U(e3)|

    SciTech Connect

    de Gouvea, Andre; Jenkins, James; Kayser, Boris; /Fermilab

    2005-03-01

    Is the relatively isolated member of the neutrino mass spectrum heavier or lighter than the two closely-spaced members? This question--the character of the neutrino mass hierarchy--is of great theoretical interest. All previously identified experiments for addressing it via neutrino oscillations require that the currently unknown size of the U{sub e3} element of the leptonic mixing matrix (parameterized by the unknown {theta}{sub 13} mixing angle) be sufficiently large, and will utterly fail in the limit {theta}{sub 13} {yields} 0. For this reason, we explore alternative oscillation approaches that would still succeed even if {theta}{sub 13} vanishes. We identify several alternatives that require neither a nonzero |U{sub e3}| nor the presence of significant matter effects. All include multiple percent-level neutrino oscillation measurements, usually involving muon-neutrino (or antineutrino) disappearance and very long baselines. We comment on the degree of promise that these alternative approaches show.

  17. Observing Muon Neutrino to Electron Neutrino Oscillations in the NOνA Experiment

    SciTech Connect

    Xin, Tian

    2016-01-01

    Neutrino oscillations offers an insight on new physics beyond the Standard Model. The three mixing angles (θ12, θ13 and θ23) and the two mass splittings (Δm2 and Αm2 ) have been measured by different neutrino oscillation experiments. Some other parameters including the mass ordering of different neutrino mass eigenstates and the CP violation phase are still unknown. NOνA is a long-baseline accelerator neutrino experiment, using neutrinos from the NuMI beam at Fermilab. The experiment is equipped with two functionally identical detectors about 810 kilometers apart and 14 mrad off the beam axis. In this configuration, the muon neutrinos from the NuMI beam reach the disappearance maximum in the far detector and a small fraction of that oscillates into electron neutrinos. The sensitivity to the mass ordering and CP viola- tion phase determination is greately enhanced. This thesis presents the νeappearance analysis using the neutrino data collected with the NOνA experiment between February 2014 and May 2015, which corresponds to 3.45 ×1020 protons-on-target (POT). The νe appearance analysis is performed by comparing the observed νe CC-like events to the estimated background at the far detector. The total background is predicted to be 0.95 events with 0.89 originated from beam events and 0.06 from cosmic ray events. The beam background is obtained by extrapolating near detector data through different oscillation channels, while the cosmic ray background is calculated based on out-of-time NuMI trigger data. A total of 6 electron neutrino candidates are observed in the end at the far detector which represents 3.3 σ excess over the predicted background. The NOνA result disfavors inverted mass hierarchy for δcp ϵ [0, 0.6π] at 90% C.L.

  18. Measuring Active-Sterile Neutrino Oscillations with a Stopped Pion Neutrino Source

    NASA Astrophysics Data System (ADS)

    van de Water, Richard; Louis, Bill; Mills, Geoff

    2007-04-01

    The question of the existence of light sterile neutrinos is of great interest in many areas of particle physics, astrophysics, and cosmology. Furthermore, should the MiniBooNE experiment at Fermilab confirm the LSND oscillation signal, then new measurements are required to identify the mechanism responsible for these oscillations. Possibilities include sterile neutrinos, CP or CPT violation, variable mass neutrinos, and Lorentz violation. Here we consider an experiment at a stopped pion neutrino source (the Spallation Neutron Source at ORNL) to determine if active-sterile neutrino oscillations with δm ^2 greater than 0.1 eV^2 can account for the signal. By exploiting stopped +circ decay to produce a monoenergetic νμ source, and measuring the rate of the neutral current reaction νx0.05in ^12C ->νx0.05in ^12C^*(15.11) as a function of distance from the source, we show that a convincing test for active-sterile neutrino oscillations can be performed.

  19. Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam.

    PubMed

    Abe, K; Adam, J; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, S W; Berardi, V; Berger, B E; Berkman, S; Bertram, I; Bhadra, S; Blaszczyk, F D M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Caravaca Rodríguez, J; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Curioni, A; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dufour, F; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery, S; Ereditato, A; Escudero, L; Finch, A J; Frank, E; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Gaudin, A; Giffin, S; Giganti, C; Gilje, K; Golan, T; Gomez-Cadenas, J J; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Ives, S J; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Joo, K K; Jung, C K; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; Kim, S B; Kisiel, J; Kitching, P; Kobayashi, T; Kogan, G; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kreslo, I; Kropp, W; Kubo, H; Kudenko, Y; Kumaratunga, S; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Laveder, M; Lawe, M; Lazos, M; Lee, K P; Licciardi, C; Lim, I T; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Lopez, G D; Ludovici, L; Macaire, M; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Maruyama, T; Marzec, J; Masliah, P; Mathie, E L; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Metelko, C; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Monfregola, L; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nagasaki, T; Nakadaira, T; Nakahata, M; Nakai, T; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Naples, D; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Otani, M; Owen, R A; Oyama, Y; Pac, M Y; Palladino, V; Paolone, V; Payne, D; Pearce, G F; Perevozchikov, O; Perkin, J D; Petrov, Y; Pinzon Guerra, E S; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J-M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Retiere, F; Robert, A; Rodrigues, P A; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smith, R J; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Szeglowski, T; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Taylor, I J; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Ueno, K; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2013-11-22

    The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability. PMID:24313479

  20. Decaying majoron dark matter and neutrino masses

    SciTech Connect

    Lattanzi, Massimiliano

    2008-01-03

    We review our recent proposal of the majoron as a suitable warm dark matter candidate. The majoron is the Goldstone boson associated to the spontaneous breaking of ungauged lepton number, one of the mechanisms proposed to give rise to neutrino masses. The majoron can acquire a mass through quantum gravity effects, and can possibly account for the observed dark matter component of the Universe. We present constraints on the majoron lifetime, mass and abundance obtained by the analysis of the cosmic microwave background data. We find that, in the case of thermal production, the limits for the majoron mass read 0.12 keV or approx. 250 Gyr. We also apply this results to a given seesaw model for the generation of neutrino masses, and find that this constraints the energy scale for the lepton number breaking phase transition to be > or approx. 10{sup 6} GeV. We thus find that the majoron decaying dark matter (DDM) scenario fits nicely in models where neutrino masses arise a la seesaw, and may lead to other possible cosmological implications.

  1. Measuring $\\theta_{13}$ via Muon Neutrino to Electron Neutrino Oscillations in the MINOS Experiment

    SciTech Connect

    Toner, Ruth B.

    2011-01-01

    One of the primary goals in neutrino physics at the present moment is to make a measurement of the neutrino oscillation parameter $\\theta_{13}$. This parameter, in addition to being unknown, could potentially allow for the introduction of CP violation into the lepton sector. The MINOS long-baseline neutrino oscillation experiment has the ability to make a measurement of this parameter, by looking for the oscillation of muon neutrinos to electron neutrinos between a Near and Far Detector over a distance of 735 km. This thesis discusses the development of an analysis framework to search for this oscillation mode. Two major improvements to pre-existing analysis techniques have been implemented by the author. First, a novel particle ID technique based on strip topology, known as the Library Event Matching (LEM) method, is optimized for use in MINOS. Second, a multiple bin likelihood method is developed to fit the data. These two improvements, when combined, increase MINOS' sensitivity to $\\sin^2(2\\theta_{13})$ by 27\\% over previous analyses. This thesis sees a small excess over background in the Far Detector. A Frequentist interpretation of the data rules out $\\theta_{13}=0$ at 91\\%. A Bayesian interpretation of the data is also presented, placing the most stringent upper boundary on the oscillation parameter to date, at $\\sin^2(2\\theta_{13})<0.09(0.015)$ for the Normal (Inverted) Hierarchy and $\\delta_{CP}=0$.

  2. The discovery reach of CP violation in neutrino oscillation with non-standard interaction effects

    NASA Astrophysics Data System (ADS)

    Rahman, Zini; Dasgupta, Arnab; Adhikari, Rathin

    2015-06-01

    We have studied the CP violation discovery reach in a neutrino oscillation experiment with superbeam, neutrino factory and monoenergetic neutrino beam from the electron capture process. For NSI satisfying model-dependent bound for shorter baselines (like CERN-Fréjus set-up) there is insignificant effect of NSI on the the discovery reach of CP violation due to δ. Particularly, for the superbeam and neutrino factory we have also considered relatively longer baselines for which there could be significant NSI effects on CP violation discovery reach for higher allowed values of NSI. For the monoenergetic beam only shorter baselines are considered to study CP violation with different nuclei as neutrino sources. Interestingly for non-standard interactions—{{\\varepsilon }eμ } and {{\\varepsilon }eτ } of neutrinos with matter during propagation in longer baselines in the superbeam, there is the possibility of better discovery reach of CP violation than that with only Standard Model interactions of neutrinos with matter. For complex NSI we have shown the CP violation discovery reach in the plane of Dirac phase δ and NSI phase {{φ }ij}. The CP violation due to some values of δ remain unobservable with present and near future experimental facilities in the superbeam and neutrino factory. However, in the presence of some ranges of off-diagonal NSI phase values there are some possibilities of discovering total CP violation for any {{δ }CP} value even at 5σ confidence level for neutrino factory. Our analysis indicates that for some values of NSI phases total CP violation may not be at all observable for any values of δ. Combination of shorter and longer baselines could indicate in some cases the presence of NSI. However, in general for NSIs ≲ 1 the CP violation discovery reach is better in neutrino factory set-ups. Using a neutrino beam from the electron capture process for nuclei 50110Sn and 152Yb, we have shown the discovery reach of CP violation in a neutrino

  3. Addendum to: Gen. Rel. Grav. 28 (1996) 1161, First Prize Essay for 1996: Neutrino Oscillations and Supernovae

    NASA Astrophysics Data System (ADS)

    Ahluwalia-Khalilova, D. V.

    2004-09-01

    In a 1996 JRO Fellowship Research Proposal (Los Alamos), the author suggested that neutrino oscillations may provide a powerful indirect energy transport mechanism to supernovae explosions. The principal aim of this addendum is to present the relevant unedited text of Section 1 of that proposal. We then briefly remind, (a) of an early suggestion of Mazurek on vacuum neutrino oscillations and their relevance to supernovae explosion, and (b) Wolfenstein's result on suppression of the effect by matter effects. We conclude that whether or not neutrino oscillations play a significant role in supernovae explosions shall depend if there are shells/regions of space in stellar collapse where matter effects play no essential role. Should such regions exist in actual astrophysical situations, the final outcome of neutrino oscillations on supernovae explosions shall depend, in part, on whether or not the LNSD signal is confirmed. Importantly, the reader is reminded that neutrino oscillations form a set of flavor-oscillation clocks and these clock suffer gravitational redshift which can be as large as 20 percent. This effect must be incorporated fully into any calculation of supernova explosion.

  4. PPPC 4 DMν: a Poor Particle Physicist Cookbook for Neutrinos from Dark Matter annihilations in the Sun

    SciTech Connect

    Baratella, Pietro; Cirelli, Marco; Hektor, Andi; Pata, Joosep; Piibeleht, Morten; Strumia, Alessandro

    2014-03-27

    We provide ingredients and recipes for computing neutrino signals of TeV-scale Dark Matter (DM) annihilations in the Sun. For each annihilation channel and DM mass we present the energy spectra of neutrinos at production, including: state-of-the-art energy losses of primary particles in solar matter, secondary neutrinos, electroweak radiation. We then present the spectra after propagation to the Earth, including (vacuum and matter) flavor oscillations and interactions in solar matter. We also provide a numerical computation of the capture rate of DM particles in the Sun. These results are available in numerical form http://www.marcocirelli.net/PPPC4DMID.html.

  5. PPPC 4 DMν: a Poor Particle Physicist Cookbook for Neutrinos from Dark Matter annihilations in the Sun

    NASA Astrophysics Data System (ADS)

    Baratella, Pietro; Cirelli, Marco; Hektor, Andi; Pata, Joosep; Piibeleht, Morten; Strumia, Alessandro

    2014-03-01

    We provide ingredients and recipes for computing neutrino signals of TeV-scale Dark Matter (DM) annihilations in the Sun. For each annihilation channel and DM mass we present the energy spectra of neutrinos at production, including: state-of-the-art energy losses of primary particles in solar matter, secondary neutrinos, electroweak radiation. We then present the spectra after propagation to the Earth, including (vacuum and matter) flavor oscillations and interactions in solar matter. We also provide a numerical computation of the capture rate of DM particles in the Sun. These results are available in numerical form.

  6. First neutrino oscillation measurements in NOvA

    NASA Astrophysics Data System (ADS)

    Messier, M. D.

    2016-07-01

    The NOvA experiment uses the Fermilab NuMI neutrino beam and a newly constructed 14 kt detector to address several open questions in neutrino oscillations including the neutrino mass hierarchy, the precise value of the angle θ23, and the CP-violating phase δCP. The experiment has been running since 2014 and has recently released its first results from an equivalent exposure of 2.74 ×1020 protons-on-target equal to 8% of the eventual data set. Measurements of νμ →νμ oscillations find Δ m322 = (2.52-0.18+0.20) ×10-3 eV2 and 0.38 neutrino mass hierarchy. The experiment has observed νμ →νe oscillations at 3.3 σ C.L. in this early data and disfavors the inverted neutrino mass hierarchy in the range 0.1 π <δCP < 0.5 π at the 90% C.L.

  7. Short baseline neutrino oscillations: When entanglement suppresses coherence

    NASA Astrophysics Data System (ADS)

    Boyanovsky, Daniel

    2011-09-01

    For neutrino oscillations to take place the entangled quantum state of a neutrino and a charged lepton produced via charged current interactions must be disentangled. Implementing a nonperturbative Wigner-Weisskopf method we obtain the correct entangled quantum state of neutrinos and charged leptons from the (two-body) decay of a parent particle. The source lifetime and disentanglement length scale lead to a suppression of the oscillation probabilities in short-baseline experiments. The suppression is determined by πLs/Losc where Ls is the smallest of the decay length of the parent particle or the disentanglement length scale. For Ls≥Losc coherence and oscillations are suppressed. These effects are more prominent in short base line experiments and at low neutrino energy. We obtain the corrections to the appearance and disappearance probabilities modified by both the lifetime of the source and the disentanglement scale and discuss their implications for accelerator and reactor experiments. These effects imply that fits to the experimental data based on the usual quantum mechanical formulation underestimate sin⁡2(2θ) and δm2, and are more dramatic for δm2≃eV2, the mass range for new generations of sterile neutrinos that could explain the short-baseline anomalies and long disentanglement length scales.

  8. Effects of Recent Reactor Anti-neutrino Spectra on Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Sterbenz, Ciara

    2015-10-01

    The β-decay of nuclear fission fragments produces a very large ve flux from nuclear reactions. The shape of the expected flux has previously been predicted by converting the measured β-electron spectrum to an ve spectrum. Recent reactor neutrino experiments, however, find a large shoulder in the observed ve spectrum relative to this prediction in the energy region 5 - 7 MeV. Accurate knowledge of the expected ve flux from reactors is important for oscillation experiments that only involve one neutrino detector. In this project, I examine the implications of these spectral changes on the ν oscillation result found by the KamLAND experiment. At the time of their finding, the spectral anomaly from 5 - 7 MeV had not be observed. I have re-derived the oscillation parameters Δm2 and sin2 (2 θ) using the anti-neutrino flux from Daya Bay and from nuclear database predictions. With these new expected fluxes, these oscillation parameters shifted and their uncertainties increased. I compare the new oscillation parameters with those derived from solar neutrino oscillation data.

  9. The Unruh effect and oscillating neutrinos

    NASA Astrophysics Data System (ADS)

    Vir Ahluwalia, Dharam; Labun, Lance; Torrieri, Giorgio

    2016-04-01

    We give an overview of the issues and ambiguities associated with the Unruh effect, and argue that, as well as a very interesting phenomenon, it can also be used as a probe of fundamental physics. In particular, We point out that, because the detectable neutrino is not a mass Eigenstate, the Unruh effect works in a qualitatively different way than for any inertial process. For inertial processes, neutrinoes are produced as charged eigenstates, rather than as mass Eigenstates as in the comoving frame. This makes the Unruh effect detectable in microscopic processes, via, for example, p→ nl^+\\barνl decays. Such an experiment would be invaluable both as a tool to measure neutrino masses and mixing angles, and to investigate the fundamental quantization of fields.

  10. Violation of the Leggett-Garg Inequality in Neutrino Oscillations.

    PubMed

    Formaggio, J A; Kaiser, D I; Murskyj, M M; Weiss, T E

    2016-07-29

    The Leggett-Garg inequality, an analogue of Bell's inequality involving correlations of measurements on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. The phenomenon of neutrino oscillations should adhere to quantum-mechanical predictions and provide an observable violation of the Leggett-Garg inequality. We demonstrate how oscillation phenomena can be used to test for violations of the classical bound by performing measurements on an ensemble of neutrinos at distinct energies, as opposed to a single neutrino at distinct times. A study of the MINOS experiment's data shows a greater than 6σ violation over a distance of 735 km, representing the longest distance over which either the Leggett-Garg inequality or Bell's inequality has been tested. PMID:27517759

  11. Violation of the Leggett-Garg Inequality in Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Formaggio, J. A.; Kaiser, D. I.; Murskyj, M. M.; Weiss, T. E.

    2016-07-01

    The Leggett-Garg inequality, an analogue of Bell's inequality involving correlations of measurements on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. The phenomenon of neutrino oscillations should adhere to quantum-mechanical predictions and provide an observable violation of the Leggett-Garg inequality. We demonstrate how oscillation phenomena can be used to test for violations of the classical bound by performing measurements on an ensemble of neutrinos at distinct energies, as opposed to a single neutrino at distinct times. A study of the MINOS experiment's data shows a greater than 6 σ violation over a distance of 735 km, representing the longest distance over which either the Leggett-Garg inequality or Bell's inequality has been tested.

  12. Oscillation degeneracy in non-standard neutrino interactions

    NASA Astrophysics Data System (ADS)

    Wright, Warren

    2016-06-01

    The standard theory describing neutrino oscillations only uses the interactions predicted by the Standard Model of particle physics. However, there is plenty of room for non-standard interactions (NSI) to exist. This is because extra interactions are allowed by experimental error bars and even expected at some level from effective theory arguments. This research is focused on examining the phenomenological consequences of the new physics of NSI at large atmospheric neutrino detectors like IceCube DeepCore. Of particular focus are the degeneracies between and within the standard neutrino oscillation parameters and the NSI parameters. These degeneracies will be explored both analytically and numerically, and strategies to lift them will also be discussed. This research is largely based on [1].

  13. Status of the Daya Bay Reactor Neutrino Oscillation Experiment

    SciTech Connect

    Daya Bay Collaboration; Lin, Cheng-Ju Stephen

    2010-12-15

    The last unknown neutrino mixing angle theta_13 is one of the fundamental parameters of nature; it is also a crucial parameter for determining the sensitivity of future long-baseline experiments aimed to study CP violation in the neutrino sector. Daya Bay is a reactor neutrino oscillation experiment designed to achieve a sensitivity on the value of sin^2(2*theta_13) to better than 0.01 at 90percent CL. The experiment consists of multiple identical detectors placed underground at different baselines to minimize systematic errors and suppress cosmogenic backgrounds. With the baseline design, the expected anti-neutrino signal at the far site is about 360 events per day and at each of the near sites is about 1500 events per day. An overview and current status of the experiment will be presented.

  14. Search for neutrino oscillations at the Brookhaven AGS

    SciTech Connect

    Ahrens, L.A.; Aronson, S.H.; Connolly, P.L.; Gibbard, B.G.; Murtagh, M.J.; Murtagh, S.J.; Terada, S.; White, D.H.; Callas, J.L.; Cutts, D.

    1985-02-20

    We report on a search for neutrino oscillations of the type nu/sub ..mu../ ..-->.. nu/sub e/ in a detector located an effective distance of 96m from the neutrino source in the wide band neutrino beam at the Brookhaven AGS. No excess of electron events was observed. The resulting upper limit on the strength of the mixing between nu/sub ..mu../ and nu/sub e/ in the case of large mass difference ..delta..m/sup 2/ = absolute value m/sub 1//sup 2/ - m/sub 2//sup 2/ between the neutrino mass eigenstates m/sub 1/ and m/sub 2/ is sin/sup 2/2..cap alpha.. less than or equal to 3.4 x 10/sup -3/ at 90% CL. The corresponding upper limit for small mass difference is ..delta..m/sup 2/sin2..cap alpha.. < 0.43 eV/sup 2/. 9 refs.

  15. Matter effect to T violation at a neutrino factory

    SciTech Connect

    Miura, Takahiro; Takasugi, Eiichi; Kuno, Yoshitaka; Yoshimura, Masaki

    2001-07-01

    We analyze T violation in neutrino oscillations by using perturbation methods with respect to {Delta}m{sub 21}{sup 2}L/2E and {delta}a(x)L/2E, where {delta}a(x) represents the matter density fluctuation from its average value. We find that the matter contribution to T violation arises from interference between {Delta}m{sub 21}{sup 2}L/2E and {delta}a(x)L/2E. To second order, the symmetric and asymmetric matter density fluctuations give effects to the sin{delta} (intrinsic) and the cos{delta} (fake) parts of T violation. We give their analytic forms and analyze the matter contribution to the sin{delta} and cos{delta} terms. We find that, for L=3000 km, both the symmetric and asymmetric matter density fluctuations give negligible contributions to T violation and that thus the constant (average) matter density gives a good approximation. On the other hand, we argue that, for L=7000 km or longer, T violation turns out to become very small due to the cancellation between the first and second order terms. This shows that the constant (average) matter approximation is not valid.

  16. Long baseline neutrino oscillation experiment at the AGS

    NASA Astrophysics Data System (ADS)

    Beavis, D.; Carroll, A.; Chiang, I.

    1995-04-01

    The authors present a design for a multidetector long baseline neutrino oscillation experiment at the BNL AGS. It has been approved by the BNL-HENP-PAC as AGS Experiment 889. The experiment will search for oscillations in the nu(sub mu) disappearance channel and the nu(sub mu) reversible reaction nu(sub e) appearance channel by means of four identical neutrino detectors located 1, 3, 24, and 68 km from the AGS neutrino source. Observed depletion of the nu(sub mu) flux (via quasi-elastic muon neutrino events, nu(sub mu)n yields mu(-)p) in the far detectors not attended by an observed proportional increase of the nu(sub e) flux (via quasi-elastic electron neutrino events, nu(sub e)n yields e(-)p) in those detectors will be prima facie evidence for the oscillation channel nu(sub mu) reversible reaction nu(sub tau). The experiment is directed toward exploration of the region of the neutrino oscillation parameters Delta m(exp 2) and sin(exp 2) 2 theta, suggested by the Kamiokande and IMB deep underground detectors but it will also explore a region more than two orders of magnitude larger than that of previous accelerator experiments. The experiment will run in a mode new to BNL. It will receive the fast extracted proton beam on the neutrino target approximately 20 hours per day when the AGS is not filling RHIC. A key aspect of the experimental design involves placing the detectors 1.5 degrees off the center line of the neutrino beam, which has the important advantage that the central value of the neutrino energy (approximately 1 GeV) and the beam spectral shape are, to a good approximation, the same in all four detectors. The proposed detectors are massive, imaging, water Cherenkov detectors similar in large part to the Kamiokande and IMB detectors. The design has profited from their decade-long experience, and from the detector designs of the forthcoming SNO and SuperKamiokande detectors.

  17. Experimental constraints on the neutrino oscillations and a simple model of three-flavor mixing

    SciTech Connect

    Raczka, P.A.; Szymacha, A. ); Tatur, S. )

    1994-02-01

    A simple model of neutrino mixing is considered which contains only one right-handed neutrino field coupled, via the mass term, to the three usual left-handed fields. This is the simplest model that allows for three-flavor neutrino oscillations. The existing experimental limits on the neutrino oscillations are used to obtain constraints on the two free-mixing parameters of the model. A specific sum rule relating the oscillation probabilities of different flavors is derived.

  18. Studying neutrino oscillations using quasi-elastic events in MINOS

    SciTech Connect

    Kumaratunga, Sujeewa Terasita; /Minnesota U.

    2008-02-01

    MINOS (Main Injector Neutrino Oscillation Search), is a long baseline neutrino experiment designed to search for neutrino oscillations using two detectors at Fermi National Accelerator Laboratory, IL (Near Detector) and Soudan, MN (Far Detector). It will study {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations and make a measurement on the oscillation parameters, {Delta}m{sub 23}{sup 2} and sin{sup 2} 2{theta}{sub 23}, via a {nu}{sub {mu}} beam made at Fermilab. Charge current neutrino interactions in the MINOS detectors are of three types: quasi-elastic scattering (QEL), resonance scattering (RES) and deep inelastic scattering (DIS). Of these, quasi-elastic scattering leaves the cleanest signal with just one {mu} and one proton in the final state, thus rendering the reconstruction of the neutrino energy more accurate. This thesis will outline a method to separate QEL events from the others in the two detectors and perform a calculation of {Delta}m{sub 23}{sup 2} and sin{sup 2} 2{theta}{sub 23} using those events. The period under consideration was May 2005 to February 2006. The number of observed quasi-elastic events with energies below 10 GeV was 29, where the expected number was 60 {+-} 3. A fit to the energy distribution of these events gives {Delta}m{sub 23}{sup 2} = 2.91{sub -0.53}{sup +0.49}(stat){sub -0.09}{sup +0.08}(sys) x 10{sup -3} eV{sup 2} and sin{sup 2} 2{theta}{sub 23} = 0.990{sub -0.180}(stat){sub -0.030}(sys).

  19. Cosmologically safe eV-scale sterile neutrinos and improved dark matter structure.

    PubMed

    Dasgupta, Basudeb; Kopp, Joachim

    2014-01-24

    We show that sterile neutrinos with masses ≳1  eV, as motivated by several short baseline oscillation anomalies, can be consistent with cosmological constraints if they are charged under a hidden sector force mediated by a light boson. In this case, sterile neutrinos experience a large thermal potential that suppresses mixing between active and sterile neutrinos in the early Universe, even if vacuum mixing angles are large. Thus, the abundance of sterile neutrinos in the Universe remains very small, and their impact on big bang nucleosynthesis, cosmic microwave background, and large-scale structure formation is negligible. It is conceivable that the new gauge force also couples to dark matter, possibly ameliorating some of the small-scale structure problems associated with cold dark matter. PMID:24484131

  20. A study of muon neutrino to electron neutrino oscillations in the MINOS experiment

    SciTech Connect

    Yang, Tingjun

    2009-03-01

    The observation of neutrino oscillations (neutrino changing from one flavor to another) has provided compelling evidence that the neutrinos have non-zero masses and that leptons mix, which is not part of the original Standard Model of particle physics. The theoretical framework that describes neutrino oscillation involves two mass scales (Δmatm2 and Δmsol2), three mixing angles (θ12, θ23, and θ13) and one CP violating phase (δCP). Both mass scales and two of the mixing angles (θ12 and θ23) have been measured by many neutrino experiments. The mixing angle θ13, which is believed to be very small, remains unknown. The current best limit on θ13 comes from the CHOOZ experiment: θ13 < 11° at 90% C.L. at the atmospheric mass scale. δCP is also unknown today. MINOS, the Main Injector Neutrino Oscillation Search, is a long baseline neutrino experiment based at Fermi National Accelerator Laboratory. The experiment uses a muon neutrino beam, which is measured 1 km downstream from its origin in the Near Detector at Fermilab and then 735 km later in the Far Detector at the Soudan mine. By comparing these two measurements, MINOS can obtain parameters in the atmospheric sector of neutrino oscillations. MINOS has published results on the precise measurement of Δmatm2 and θ23 through the disappearance of muon neutrinos in the Far Detector and on a search for sterile neutrinos by looking for a deficit in the number of neutral current interactions seen in the Far Detector. MINOS also has the potential to improve the limit on the neutrino mixing angle θ13 or make the first measurement of its value by searching for an electron neutrino appearance signal in the Far Detector. This is the focus of the study presented in this thesis. We developed a neural network based algorithm to

  1. Neutrino Mass Hierarchy and Neutrino Oscillation Parameters with One Hundred Thousand Reactor Events

    NASA Astrophysics Data System (ADS)

    Capozzi, F.; Lisi, E.; Marrone, A.

    High-statistics reactor neutrino experiments at medium baselines will probe mass-mixing parameters governing neutrino oscillations at long wavelength, driven by the (δm2, θ12) and at short wavelength, driven by (Δm2, θ13).The interference between these two oscillations will allow to probe the mass hierarchy. The determination of the neutrino mass spectrum hierarchy, however, will require an unprecedented level of detector performance and collected statistics, and the control of several systematics at (sub)percent level. In this work we perform accurate theoretical calculations of reactor event spectra and refined statistical analyses to show that with O(105) reactor events, a typical sensitivity of ∼ 2σ could be achieved by an experiment such as JUNO. We also show the impact of the energy scale and spectrum shape systematics on the determination of the hierarchy.

  2. Panofsky Prize Lecture: Evidence for Oscillation of Atmospheric Neutrinos

    NASA Astrophysics Data System (ADS)

    Totsuka, Yoji

    2002-04-01

    Atmospheric neutrinos are decay products of pions and kaons (and of their decay products muons) produced by nuclear interactions of cosmic rays with air nuclei. Though their flux is not known well, only within 20 %, physics quantities that are independent of the flux uncertainty exist. The ratio of the number of muon neutrinos to the number of electron neutrinos is estimated to be accurate within 5 %. The other quantity is the shape of the zenith-angle distribution. Kamiokande and Super-Kamiokande are water Cherenkov detectors with 3,000 ton and 50,000 ton pure water, respectively. Kamiokande was operational in 1983 - 1996, and Super-K in 1996 - 2001 and 2003 - in future. We had already noted in 1988 that the observed μ/e ratio, which represented ν_mu/ν_e, was smaller by about 40 %. Later in 1994 we noted that the zenith angle distribution of muon neutrinos was strongly distorted, namely much fewer muons observed in the upward direction, while downward-going muons were what we expected. Electrons were quite normal. In 1996 Super-Kamiokande was ready. Its fiducial volume is 22.5 kton, much larger than Kamiokande's 1.04 kton. In 1998 based on 25.5 kton years of data we presented convincing results on the small μ/e ratio which was caused by fewer number of muons in the upward direction. The essential feature of the observed anomaly was that the disappearance of muon neutrinos depended strongly on their path length and on their energies. Electrons showed no anomaly within the experimental limit. These results were quantitatively and almost uniquely explained by oscillation of muon neutrinos to tau neutrinos, thus evidence for the finite but tiny mass of neutrinos.

  3. Wave-packet treatment of reactor neutrino oscillation experiments and its implications on determining the neutrino mass hierarchy

    NASA Astrophysics Data System (ADS)

    Chan, Yat-Long; Chu, M.-C.; Tsui, Ka Ming; Wong, Chan Fai; Xu, Jianyi

    2016-06-01

    We derive the neutrino flavor transition probabilities with the neutrino treated as a wave packet. The decoherence and dispersion effects from the wave-packet treatment show up as damping and phase-shifting of the plane-wave neutrino oscillation patterns. If the energy uncertainty in the initial neutrino wave packet is larger than around 0.01 of the neutrino energy, the decoherence and dispersion effects would degrade the sensitivity of reactor neutrino experiments to mass hierarchy measurement to lower than 3 σ confidence level.

  4. A combined muon-neutrino and electron-neutrino oscillation search at MiniBooNE

    SciTech Connect

    Monroe, Jocelyn R.; /Columbia U.

    2006-07-01

    MiniBooNE seeks to corroborate or refute the unconfirmed oscillation result from the LSND experiment. If correct, the result implies that a new kind of massive neutrino, with no weak interactions, participates in neutrino oscillations. MiniBooNE searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations with the Fermi National Accelerator Laboratory 8 GeV beam line, which produces a {nu}{sub {mu}} beam with an average energy of {approx} 0.8 GeV and an intrinsic {nu}{sub e} content of 0.4%. The neutrino detector is a 6.1 m radius sphere filled with CH{sub 2}, viewed by 1540 photo-multiplier tubes, and located 541 m downstream from the source. This work focuses on the estimation of systematic errors associated with the neutrino flux and neutrino interaction cross section predictions, and in particular, on constraining these uncertainties using in-situ MiniBooNE {nu}{sub {mu}} charged current quasielastic (CCQE) scattering data. A data set with {approx} 100,000 events is identified, with 91% CCQE purity. This data set is used to measure several parameters of the CCQE cross section: the axial mass, the Fermi momentum, the binding energy, and the functional dependence of the axial form factor on four-momentum transfer squared. Constraints on the {nu}{sub {mu}} and {nu}{sub e} fluxes are derived using the {nu}{sub {mu}} CCQE data set. A Monte Carlo study of a combined {nu}{sub {mu}} disappearance and {nu}{sub e} appearance oscillation fit is presented, which improves the {nu}{sub {mu}} {yields} {nu}{sub e} oscillation sensitivity of MiniBooNE with respect to a {nu}{sub e} appearance-only fit by 1.2-1.5{sigma}, depending on the value of {Delta}m{sup 2}.

  5. Neutrino mass hierarchy and electron neutrino oscillation parameters with one hundred thousand reactor events

    NASA Astrophysics Data System (ADS)

    Capozzi, F.; Lisi, E.; Marrone, A.

    2014-01-01

    Proposed medium-baseline reactor neutrino experiments offer unprecedented opportunities to probe, at the same time, the mass-mixing parameters which govern νe oscillations both at long wavelength (δm2 and θ12) and at short wavelength (Δm2 and θ13), as well as their tiny interference effects related to the mass hierarchy (i.e., the relative sign of Δm2 and δm2). In order to take full advantage of these opportunities, precision calculations and refined statistical analyses of event spectra are required. In such a context, we revisit several input ingredients, including nucleon recoil in inverse beta decay and its impact on energy reconstruction and resolution, hierarchy and matter effects in the oscillation probability, spread of reactor distances, irreducible backgrounds from geoneutrinos and from far reactors, and degeneracies between energy scale and spectrum shape uncertainties. We also introduce a continuous parameter α, which interpolates smoothly between normal hierarchy (α =+1) and inverted hierarchy (α =-1). The determination of the hierarchy is then transformed from a test of hypothesis to a parameter estimation, with a sensitivity given by the distance of the true case (either α=+1 or α =-1) from the "undecidable" case (α=0). Numerical experiments are performed for the specific setup envisaged for the JUNO project, assuming a realistic sample of O(105) reactor events. We find a typical sensitivity of ˜2σ to the hierarchy in JUNO, which, however, can be challenged by energy scale and spectrum shape systematics, whose possible conspiracy effects are investigated. The prospective accuracy reachable for the other mass-mixing parameters is also discussed.

  6. Quantum simulations of neutrino oscillations and the Majorana equation

    NASA Astrophysics Data System (ADS)

    Noh, Changsuk; Rodriguez-Lara, Blas; Angelakis, Dimitris

    2013-03-01

    Two recent works on quantum simulations of relativistic equations are presented. The first is on neutrino oscillations with trapped ions as a generalization of Dirac equation simulation in 1 spatial dimension. It is shown that with two or more ion qubits it is possible to mimic the flavour oscillations of neutrinos. The second part is on quantum simulations of the Majorana equation based on the earlier work by Casanova et al. (PRX 1, 021018). We show that by decoupling the equation, it is possible to simulate with a smaller number of qubits given that one can perform complete tomography, including the spatial degrees of freedom. We acknowledge the financial support by the National Research Foundation and Ministry of Education, Singapore.

  7. Quantum mechanics of neutrino oscillations - hand waving for pedestrians.

    SciTech Connect

    Lipkin, H. J.

    1998-12-22

    Why Hand Waving? All calculations in books describe oscillations in time. But real experiments don't measure time. Hand waving is used to convert the results of a ''gedanken time experiment'' to the result of a real experiment measuring oscillations in space. Right hand waving gives the right answer; wrong hand waving gives the wrong answer. Many papers use wrong handwaving to get wrong answers. This talk explains how to do it right and also answers the following questions: (1) A neutrino which is a mixture of two mass eigenstates is emitted with muon in the decay of a pion at rest. This is a ''missing mass experiment'' where the muon energy determines the neutrino mass. Why are the two mass states coherent? (2) A neutrino which is a mixture of two mass eigenstates is emitted at time t=0. The two mass eigenstates move with different velocities and arrive at the detector at different times. Why are the two mass states coherent? (3) A neutrino is a mixture of two overlapping wave packets with different masses moving with different velocities. Will the wave packets eventually separate? If yes, when?

  8. Kinetic equations for baryogenesis via sterile neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Asaka, Takehiko; Eijima, Sintaro; Ishida, Hiroyuki

    2012-02-01

    We investigate baryogenesis in the νMSM (neutrino Minimal Standard Model), which is the SM extended by three right-handed neutrinos with masses below the electroweak scale. The baryon asymmetry of the universe can be generated by the mechanism via flavor oscillation of right-handed (sterile) neutrinos which are responsible to masses of active neutrinos confirmed by various experiments. We present the kinetic equations for the matrix of densities of leptons which describe the generation of asymmetries. Especially, the momentum dependence of the matrix of densities is taken into account. By solving these equations numerically, it is found that the momentum distribution is significantly distorted from the equilibrium one, since the production for the modes with lower momenta k << T (T is the temperature of the universe) is enhanced, while suppressed for higher modes. As a result, the most important mode for the yields of sterile neutrinos as well as the baryon asymmetry is k simeq 2T, which is smaller than langlekrangle inferred from the thermal average. The comparison with the previous works is also discussed.

  9. Long-Range Lepton Flavor Interactions and Neutrino Oscillations

    SciTech Connect

    Davoudiasl, H.; Lee, H-S; Marciano, W.

    2011-03-31

    Recent results from the MINOS accelerator neutrino experiment suggest a possible difference between {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance oscillation parameters, which one may ascribe to a new long distance potential acting on neutrinos. As a specific example, we consider a model with gauged B - L{sub e} - 2L{sub {tau}} number which contains an extremely light new vector boson, m{sub Z}, < 10{sup -18} eV and extraordinarily weak coupling {alpha}{prime} {approx}< 10{sup -52}. In that case, differences between {nu}{sub {mu}} {yields} {nu}{sub {tau}} and {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub {tau}} oscillations can result from a long-range potential due to neutrons in the Earth and the Sun that distinguishes {nu}{sub {mu}} and {nu}{sub {tau}} on Earth, with a potential difference of {approx} 6 x 10{sup -14} eV, and changes sign for anti-neutrinos. We show that existing solar, reactor, accelerator, and atmospheric neutrino oscillation constraints can be largely accommodated for values of parameters that help explain the possible MINOS anomaly by this new physics, although there is some tension with atmospheric constraints. A long-range interaction, consistent with current bounds, could have very pronounced effects on atmospheric neutrino disappearance in the 20-50 GeV range that will be studied with the IceCube DeepCore array, currently in operation, and can have a significant effect on future high-precision long-baseline oscillation experiments which aim for {+-}1% sensitivity, in {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance, separately. Together, these experiments can extend the reach for new long-distance effects well beyond current bounds and test their relevance to the aforementioned MINOS anomaly. We also point out that long-range potentials originating from the Sun could lead to annual modulations of neutrino data at the percent level, due to the variation of the Earth-Sun distance. A similar phenomenology is shown to apply to

  10. Novel Frameworks for Dark Matter and Neutrino Masses

    NASA Astrophysics Data System (ADS)

    Schmidt, Daniel

    2013-12-01

    The established light neutrino masses and the Dark Matter of the Universe both require physics beyond the Standard Model for their theoretical explanation. Models that provide a common framework for these two issues are very attractive. In particular, radiative mechanisms naturally yield light neutrino masses due to loop suppression factors. These corrections can comprise a link to the physics of Dark Matter. In most considerations, the Dark Matter relic density is produced by freeze-out. This thesis contributes to the elds of radiative neutrino masses and frozen-out Dark Matter. In detail, it is shown that in the Ma-model, right-handed neutrino Dark Matter can be directly detected by photon exchange at one-loop level. The Zee{Babu-model is extended such that it enjoys a global symmetry based on baryon and lepton number. This symmetry generates light neutrino masses and a mass for a stable Dark Matter particle by its spontaneous breaking. Moreover, this thesis provides a new production mechanism for keV sterile neutrino Dark Mattetr, which is based on the freeze-in scenario. In particular, keV sterile neutrino Dark Matter produced by the decay of a frozen-in scalar is investigated.

  11. Sterile neutrino dark matter: Weak interactions in the strong coupling epoch

    NASA Astrophysics Data System (ADS)

    Venumadhav, Tejaswi; Cyr-Racine, Francis-Yan; Abazajian, Kevork N.; Hirata, Christopher M.

    2016-08-01

    We perform a detailed study of the weak interactions of standard model neutrinos with the primordial plasma and their effect on the resonant production of sterile neutrino dark matter. Motivated by issues in cosmological structure formation on small scales, and reported x-ray signals that could be due to sterile neutrino decay, we consider 7 keV-scale sterile neutrinos. Oscillation-driven production of such sterile neutrinos occurs at temperatures T ≳100 MeV , where we study two significant effects of weakly charged species in the primordial plasma: (1) the redistribution of an input lepton asymmetry; (2) the opacity for active neutrinos. We calculate the redistribution analytically above and below the quark-hadron transition, and match with lattice QCD calculations through the transition. We estimate opacities due to tree-level processes involving leptons and quarks above the quark-hadron transition, and the most important mesons below the transition. We report final sterile neutrino dark matter phase space densities that are significantly influenced by these effects, and yet relatively robust to remaining uncertainties in the nature of the quark-hadron transition. We also provide transfer functions for cosmological density fluctuations with cutoffs at k ≃10 h Mpc-1 , that are relevant to galactic structure formation.

  12. Nonstandard neutrino-neutrino refractive effects in dense neutrino gases

    SciTech Connect

    Blennow, Mattias; Mirizzi, Alessandro; Serpico, Pasquale D.; /CERN /Fermilab

    2008-10-01

    We investigate the effects of nonstandard four-fermion neutrino-neutrino interactions on the flavor evolution of dense neutrino gases. We find that in the regions where the neutrino-neutrino refractive index leads to collective flavor oscillations, the presence of new neutrino interactions can produce flavor equilibration in both normal and inverted neutrino mass hierarchy. In realistic supernova environments, these effects are significant if the nonstandard neutrino-neutrino interaction strength is comparable to the one expected in the standard case, dominating the ordinary matter potential. However, very small nonstandard neutrino-neutrino couplings are enough to trigger the usual collective neutrino flavor transformations in the inverted neutrino mass hierarchy, even if the mixing angle vanishes exactly.

  13. SHM of galaxies embedded within condensed neutrino matter

    NASA Astrophysics Data System (ADS)

    Morley, P. D.; Buettner, D. J.

    2015-11-01

    We re-examine the question of condensed neutrino objects (degenerate neutrino matter) based on new calculations. The potential show-stopper issue of free-streaming light neutrinos inhibiting galaxy formation is addressed. We compute the period associated with simple harmonic motion (SHM) of galaxies embedded within condensed neutrino objects. For observational consequences, we examine the rotational velocities of embedded galaxies using Hickson 88A (N6978) as the prototype. Finally, we point out that degenerate neutrino objects repel each other in overlap and we compute directly the repulsive force between two interesting and relevant configurations. An outstanding issue is whether the accompanying tidal forces generated by condensed neutrino matter on embedded galaxies give rise to galactic bulges and halos.

  14. Adiabatic and nonadiabatic perturbation theory for coherence vector description of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Hollenberg, Sebastian; Päs, Heinrich

    2012-01-01

    The standard wave function approach for the treatment of neutrino oscillations fails in situations where quantum ensembles at a finite temperature with or without an interacting background plasma are encountered. As a first step to treat such phenomena in a novel way, we propose a unified approach to both adiabatic and nonadiabatic two-flavor oscillations in neutrino ensembles with finite temperature and generic (e.g., matter) potentials. Neglecting effects of ensemble decoherence for now, we study the evolution of a neutrino ensemble governed by the associated quantum kinetic equations, which apply to systems with finite temperature. The quantum kinetic equations are solved formally using the Magnus expansion and it is shown that a convenient choice of the quantum mechanical picture (e.g., the interaction picture) reveals suitable parameters to characterize the physics of the underlying system (e.g., an effective oscillation length). It is understood that this method also provides a promising starting point for the treatment of the more general case in which decoherence is taken into account.

  15. Neutrino oscillation physics potential of the T2K experiment

    NASA Astrophysics Data System (ADS)

    T2K Collaboration; Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bartet-Friburg, P.; Bass, M.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berger, B. E.; Berkman, S.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; de Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Escudero, L.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haegel, L.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; King, S.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Koga, T.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, J. P.; Ludovici, L.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Riccio, C.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaker, F.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2015-04-01

    The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ _{13} have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin ^22θ _{23}, the octant of θ _{23}, and the mass hierarchy, in addition to the measurements of δ _{CP}, sin ^2θ _{23}, and Δ m^2_{32}, for various combinations of ν-mode and bar {ν }-mode data-taking. With an exposure of 7.8× 10^{21} protons-on-target, T2K can achieve 1σ resolution of 0.050 (0.054) on sin ^2θ _{23} and 0.040 (0.045)× 10^{-3} {eV}^2 on Δ m^2_{32} for 100% (50%) neutrino beam mode running assuming sin ^2θ _{23}=0.5 and Δ m^2_{32} = 2.4× 10^{-3} eV^2. T2K will have sensitivity to the CP-violating phase δ _{CP} at 90% C.L. or better over a significant range. For example, if sin ^22θ _{23} is maximal (i.e. θ _{23}=45°) the range is -115° < δ _{CP}< -60° for normal hierarchy and +50° < δ _{CP}< +130° for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero δ _{CP} is substantially increased compared to if each experiment is analyzed alone.

  16. Residual Symmetries Applied to Neutrino Oscillations at NO ν A and T2K

    DOE PAGESBeta

    Hanlon, Andrew D.; Repko, Wayne W.; Dicus, Duane A.

    2014-01-01

    Tmore » he results previously obtained from the model-independent application of a generalized hidden horizontal Z 2 symmetry to the neutrino mass matrix are updated using the latest global fits for the neutrino oscillation parameters.he resulting prediction for the Dirac CP phase δ D is in agreement with recent results from2K.he distribution for the Jarlskog invariant J ν has become sharper and appears to be approaching a particular region.he approximate effects of matter on long-baseline neutrino experiments are explored, and it is shown how the weak interactions between the neutrinos and the particles that make up the Earth can help to determine the mass hierarchy. A similar strategy is employed to show how NO ν A and2K could determine the octant of θ a ( ≡ θ 23 ) . Finally, the exact effects of matter are obtained numerically in order to make comparisons with the form of the approximate solutions. From this analysis there emerge some interesting features of the effective mass eigenvalues.« less

  17. 11B and constraints on neutrino oscillations and spectra from neutrino nucleosynthesis.

    PubMed

    Austin, Sam M; Heger, Alexander; Tur, Clarisse

    2011-04-15

    We study the sensitivity to variations in the triple-alpha and 12C(α,γ)16O reaction rates, of the yield of the neutrino-process isotopes 7Li, 11B, 19F, 138La, and 180Ta in core-collapse supernovae. Compared to solar abundances, less than 15% of 7Li, about 25%-80% of 19F, and about half of 138La is produced in these stars. Over a range of ±2σ for each helium-burning rate, 11B is overproduced and the yield varies by an amount larger than the variation caused by the effects of neutrino oscillations. The total 11B yield, however, may eventually provide constraints on supernova neutrino spectra. PMID:21568548

  18. Neutrino mass, dark matter, and Baryon asymmetry via TeV-scale physics without fine-tuning.

    PubMed

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2009-02-01

    We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and the baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming a large hierarchy among the mass scales. Tiny neutrino masses are generated at the three-loop level due to the exact Z2 symmetry, by which the stability of the dark matter candidate is guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for successful electroweak baryogenesis. The model provides discriminative predictions especially in Higgs phenomenology, so that it is testable at current and future collider experiments. PMID:19257506

  19. Neutrino Oscillations, the Higgs Boson, and the Private Higgs Model

    NASA Astrophysics Data System (ADS)

    BenTov, Jonathan

    "CESR, PEP, PETRA, ISABELLE, p-bar p colliders, LEP, the tevatron, and ep machines are at various levels of design or construction. They will study the properties of b-matter, see weak intermediaries, and perhaps find the t-quark and the Higgs boson. Never before was there such a bestiary waiting to be discovered; and what surprises will be found!" - S. L. Glashow ("The Future of Elementary Particle Physics," Quarks and Leptons, NATO Advanced Study Institutes Series Volume 61, 1980, pp 687-713) The situation in 1980 was clearly different from the present situation in 2013, in which we face the very real possibilty that no new degrees of freedom will ever again be within reach of a collider. In an intriguing twist of fate, this very fact results in a sharp paradox for fundamental physics: the Higgs mass should be MP/m h ˜ 1017 times larger than it actually is, and the vacuum energy density of the universe should be (M P/A)4 ˜ (1031)4 times larger than it actually is, and apparently nature refuses to give us any more clues as to why. These together are what I would call the main problem of 21st century physics: despite all of the predictive success of particle physics so far, we must find a way to suitably modify the rules of quantum field theory, lest we accept the unproductive defeatist attitude that our universe is simply fine-tuned. In the meantime, there is much interesting work to be done in more "traditional" particle physics: we have learned that neutrinos actually have tiny but nonzero masses, which is clear and unambiguous evidence for physics beyond the Standard Model. I will allocate the first third of this document to phenomena related to neutrino oscillations. In particular, I would like to argue that some of the apparent differences between neutrino mixing and quark mixing are to an extent illusory, and actually many aspects of the two sectors can be understood in a coherent framework for extending the Standard Model. The remaining two-thirds of this

  20. Flavor evolution of supernova neutrinos in turbulent matter

    SciTech Connect

    Lund, Tina; Kneller, James P.

    2014-01-01

    The neutrino signal from the next galactic supernova carries with it an enormous amount of information on the explosion mechanism of a core-collapse supernova, as well as on the stellar progenitor and on the neutrinos themselves. In order to extract this information we need to know how the neutrino flavor evolves over time due to the interplay of neutrino self-interactions and matter effects. Additional turbulence in the supernova matter may impart its own signatures on the neutrino spectrum, and could partly obscure the imprints of collective and matter effects. We investigate the neutrino flavor evolution due to neutrino self-interactions, matter effects due to the shock wave propagation, and turbulence in three progenitors with masses of 8.8 M⊙, 10.8 M⊙ and 18.0 M⊙. In the lightest progenitor we find that the impact of moderate turbulence of the order 10% is limited and occurs only briefly early on. This makes the signatures of collective and matter interactions relatively straightforward to interpret. Similarly, with moderate turbulence the two heavier progenitors exhibit only minor changes in the neutrino spectrum, and collective and matter signatures persists. However, when the turbulence is increased to 30% and 50% the high density matter resonance features in the neutrino spectrum get obscured, while new features arise in the low density resonance channel and in the non-resonant channels. We conclude that with moderate amounts of turbulence spectral features of collective and matter interactions survive in all three progenitors. For the larger amounts of turbulence in the 10.8 M⊙ and 18.0 M⊙ progenitor new features arise, as others disappear.

  1. A search for muon neutrino to electron neutrino oscillations in the MINOS Experiment

    SciTech Connect

    Ochoa Ricoux, Juan Pedro

    2009-01-01

    We perform a search for vμ → ve oscillations, a process which would manifest a nonzero value of the θ13 mixing angle, in the MINOS long-baseline neutrino oscillation experiment. The analysis consists of searching for an excess of ve charged-current candidate events over the predicted backgrounds, made mostly of neutral-current events with high electromagnetic content. A novel technique to select electron neutrino events is developed, which achieves an improved separation between the signal and the backgrounds, and which consequently yields a better reach in θ13. The backgrounds are predicted in the Far Detector from Near Detector measurements. An excess is observed in the Far Detector data over the predicted backgrounds, which is consistent with the background-only hypothesis at 1.2 standard deviations.

  2. A measurement of the atmospheric neutrino flux and oscillation parameters at the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Sonley, Thomas John

    Through-going muon events are analyzed as a function of their direction of travel through the Sudbury Neutrino Observatory. Based on simulations and previous measurements, muons with a zenith angle of -1 < cos( [straight theta] zenith ) < 0.4 are selected as atmospheric neutrino-induced muons. A two- neutrino analysis of these events agrees with the oscillation parameters observed by the Super Kamiokande and Minos experiments, and places 2-D limits of [Special characters omitted.] at the 68% confidence level, and sin 2 (2 [straight theta] 23 ) > 0.33 at the 90% confidence level. In addition, the flux of atmospheric neutrinos is measured in 1-D with a 68% confidence level to be [Special characters omitted.] times the prediction of the BARTOL group based on SNO data alone, and 1.27± 0.09 times the prediction when the oscillation parameters are constrained by the Super Kamiokande and Minos results. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139- 4307. Ph. 617-253-5668; Fax 617-253-1690.)

  3. Neutrino spin dynamics in dense matter and electromagnetic field

    NASA Astrophysics Data System (ADS)

    Arbuzova, E. V.

    2008-11-01

    We discuss behavior of massive Dirac neutrino with anomalous magnetic moment propagating through dense magnetized matter on the basis of the obtained solutions of the Dirac-Pauli equation. This system of solutions demonstrates spin rotating properties and represents pure neutrino states.

  4. Light dark matter detection prospects at neutrino experiments

    NASA Astrophysics Data System (ADS)

    Kumar, Jason; Learned, John G.; Smith, Stefanie

    2009-12-01

    We consider the prospects for the detection of relatively light dark matter through direct annihilation to neutrinos. We specifically focus on the detection possibilities of water Cherenkov and liquid scintillator neutrino detection devices. We find, in particular, that liquid scintillator detectors may potentially provide excellent detection prospects for dark matter in the 4-10 GeV mass range. These experiments can provide excellent corroborative checks of the DAMA/LIBRA annual modulation signal, but may yield results for low mass dark matter in any case. We identify important tests of the ratio of electron to muon neutrino events (and neutrino versus antineutrino events), which discriminate against background atmospheric neutrinos. In addition, the fraction of events which arise from muon neutrinos or antineutrinos (Rμ and Rμ¯) can potentially yield information about the branching fractions of hypothetical dark matter annihilations into different neutrino flavors. These results apply to neutrinos from secondary and tertiary decays as well, but will suffer from decreased detectability.

  5. Neutrino oscillations: what do we know about θ13

    NASA Astrophysics Data System (ADS)

    Ernst, David

    2008-10-01

    The phenomenon of neutrino oscillations is reviewed. A new analysis tool for the recent, more finely binned Super-K atmospheric data is outlined. This analysis incorporates the full three-neutrino oscillation probabilities, including the mixing angle θ13 to all orders, and a full three- neutrino treatment of the Earth's MSW effect. Combined with the K2K, MINOS, and CHOOZ data, the upper bound on θ13 is found to arise from the Super-K atmospheric data, while the lower bound arises from CHOOZ. This is caused by the linear in θ13 terms which are of particualr importance in the region L/E>10^4 m/MeV where the sub-dominant expansion is not convergent. In addition, the enhancement of θ12 by the Earth MSW effect is found to be important for this result. The best fit value of θ13 is found to be (statistically insignificantly) negative and given by θ13=-0.07^+0.18-0.11. In collaboration with Jesus Escamilla, Vanderbilt University and David Latimer, University of Kentucky.

  6. Impact of Neutrino Flavor Oscillations on the Neutrino-Driven Wind Nucleosynthesis of an Electron-Capture Supernova

    NASA Astrophysics Data System (ADS)

    Pllumbi, Else; Tamborra, Irene; Wanajo, Shinya; Janka, Hans-Thomas; Hüdepohl, Lorenz

    2015-08-01

    Neutrino oscillations, especially to light sterile states, can affect nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of an 8.8 {M}⊙ electron-capture supernova (SN), whose hydrodynamic evolution was computed in spherical symmetry with sophisticated neutrino transport and whose Ye evolution was post-processed by including neutrino oscillations between both active and active-sterile flavors. We also take into account the α-effect as well as weak magnetism and recoil corrections in the neutrino absorption and emission processes. We observe effects on the Ye evolution that depend in a subtle way on the relative radial positions of the sterile Mikheyev-Smirnov-Wolfenstein resonances, on collective flavor transformations, and on the formation of α particles. For the adopted SN progenitor, we find that neutrino oscillations, also to a sterile state with eV mass, do not significantly affect the element formation and in particular cannot make the post-explosion wind outflow neutron-rich enough to activate a strong r-process. Our conclusions become even more robust when, in order to mimic equation-of-state-dependent corrections due to nucleon potential effects in the dense-medium neutrino opacities, six cases with reduced Ye in the wind are considered. In these cases, despite the conversion of active neutrinos to sterile neutrinos, Ye increases or is not significantly lowered compared to the values obtained without oscillations and active flavor transformations. This is a consequence of a complicated interplay between sterile-neutrino production, neutrino-neutrino interactions, and α-effect.

  7. Dark matter vs. neutrinos: the effect of astrophysical uncertainties and timing information on the neutrino floor

    SciTech Connect

    Davis, Jonathan H.

    2015-03-09

    Future multi-tonne Direct Detection experiments will be sensitive to solar neutrino induced nuclear recoils which form an irreducible background to light Dark Matter searches. Indeed for masses around 6 GeV the spectra of neutrinos and Dark Matter are so similar that experiments are said to run into a neutrino floor, for which sensitivity increases only marginally with exposure past a certain cross section. In this work we show that this floor can be overcome using the different annual modulation expected from solar neutrinos and Dark Matter. Specifically for cross sections below the neutrino floor the DM signal is observable through a phase shift and a smaller amplitude for the time-dependent event rate. This allows the exclusion power to be improved by up to an order of magnitude for large exposures. In addition we demonstrate that, using only spectral information, the neutrino floor exists over a wider mass range than has been previously shown, since the large uncertainties in the Dark Matter velocity distribution make the signal spectrum harder to distinguish from the neutrino background. However for most velocity distributions it can still be surpassed using timing information, and so the neutrino floor is not an absolute limit on the sensitivity of Direct Detection experiments.

  8. Constraint on neutrino decay with medium-baseline reactor neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    The experimental bound on lifetime of ν 3, the neutrino mass eigenstate with the smallest ν e component, is much weaker than those of ν 1 and ν 2 by many orders of magnitude to which the astrophysical constraints apply. We argue that the future reactor neutrino oscillation experiments with medium-baseline (˜50 km), such as JUNO or RENO-50, has the best chance of placing the most stringent constraint on ν3 lifetime among all neutrino experiments which utilize the artificial source neutrinos. Assuming decay into invisible states, we show by a detailed χ 2 analysis that the ν 3 lifetime divided by its mass, τ 3 /m 3, can be constrained to be τ 3 /m 3 > 7 .5 (5 .5) × 10-11 s/eV at 95% (99%) C.L. by 100 kt·years exposure by JUNO. It may be further improved to the level comparable to the atmospheric neutrino bound by its longer run. We also discuss to what extent ν 3 decay affects mass-ordering determination and precision measurements of the mixing parameters.

  9. Solar neutrinos and neutrino physics

    NASA Astrophysics Data System (ADS)

    Maltoni, Michele; Smirnov, Alexei Yu.

    2016-04-01

    Solar neutrino studies triggered and largely motivated the major developments in neutrino physics in the last 50 years. The theory of neutrino propagation in different media with matter and fields has been elaborated. It includes oscillations in vacuum and matter, resonance flavor conversion and resonance oscillations, spin and spin-flavor precession, etc. LMA MSW has been established as the true solution of the solar neutrino problem. Parameters θ_{12} and Δ m 2 21 have been measured; θ_{13} extracted from the solar data is in agreement with results from reactor experiments. Solar neutrino studies provide a sensitive way to test theory of neutrino oscillations and conversion. Characterized by long baseline, huge fluxes and low energies they are a powerful set-up to search for new physics beyond the standard 3 ν paradigm: new neutrino states, sterile neutrinos, non-standard neutrino interactions, effects of violation of fundamental symmetries, new dynamics of neutrino propagation, probes of space and time. These searches allow us to get stringent, and in some cases unique bounds on new physics. We summarize the results on physics of propagation, neutrino properties and physics beyond the standard model obtained from studies of solar neutrinos.

  10. Status of the San Onofre neutrino oscillation experiment

    SciTech Connect

    Hertenberger, R.; Chen, M.; Henrikson, H.; Mascarenhas, M.

    1993-10-01

    The San Onofre experiment is designed to investigate neutrino oscillations in the parameter space suggested by the atmospheric neutrino problem. A liquid-scintillator-based 12-ton detector will be installed at 650 m from the two units of the San Onofre power reactor. For the detection of the {anti v}{sub e}-induced inverse beta decay reaction a novel four-fold coincidence method is used allowing effective suppression of background at the relatively low shallow depth of 25 mwe. We report on the experimental method and demonstrate its feasibility by presenting results from recent test experiments performed with a prototype detector in the Tendon Gallery of the San Onofre Unit 2 reactor.

  11. Neutrinos from dark matter annihilations at the galactic center

    SciTech Connect

    Bertone, Gianfranco; Orloff, Jean; Silk, Joseph

    2004-09-15

    We discuss the prospects for detection of high energy neutrinos from dark matter (DM) annihilation at the galactic center (GC). Despite the large uncertainties associated with our poor knowledge of the distribution of dark matter in the innermost regions of the Galaxy, we determine an upper limit on the neutrino flux by requiring that the associated gamma-ray emission does not exceed the observed flux. We conclude that a neutrino flux from the GC will not be observable by Antares if dark matter is made of neutralinos with mass smaller than 650 GeV, while for heavier neutralinos, corresponding to models that will soon be probed by HESS (high energy stereoscopic system), the upper limit on the neutrino flux is barely above the Antares sensitivity. The detection of a larger flux would either require an alternative explanation, in terms of astrophysical processes, or the adoption of other dark matter candidates, disfavouring the case for neutralinos.

  12. Neutrino probes of the nature of light dark matter

    SciTech Connect

    Agarwalla, Sanjib Kumar; Mena, Olga; Blennow, Mattias; Martinez, Enrique Fernandez E-mail: blennow@mppmu.mpg.de E-mail: omena@ific.uv.es

    2011-09-01

    Dark matter particles gravitationally trapped inside the Sun may annihilate into Standard Model particles, producing a flux of neutrinos. The prospects of detecting these neutrinos in future multi-kt neutrino detectors designed for other physics searches are explored here. We study the capabilities of a 34/100 kt liquid argon detector and a 100 kt magnetized iron calorimeter detector. These detectors are expected to determine the energy and the direction of the incoming neutrino with unprecedented precision allowing for tests of the dark matter nature at very low dark matter masses, in the range of 10–25 GeV. By suppressing the atmospheric background with angular cuts, these techniques would be sensitive to dark matter-nucleon spin-dependent cross sections at the fb level, reaching down to a few ab for the most favorable annihilation channels and detector technology.

  13. Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter

    SciTech Connect

    Reddy, Sanjay

    2013-09-06

    It is now firmly established that neutrinos, which are copiously produced in the hot and dense core of the supernova, play a role in the supernova explosion mechanism and in the synthesis of heavy elements through a phenomena known as r-process nucleosynthesis. They are also detectable in terrestrial neutrino experiments, and serve as a probe of the extreme environment and complex dynamics encountered in the supernova. The major goal of the UW research activity relevant to this project was to calculate the neutrino interaction rates in hot and dense matter of relevance to core collapse supernova. These serve as key input physics in large scale computer simulations of the supernova dynamics and nucleosynthesis being pursued at national laboratories here in the United States and by other groups in Europe and Japan. Our calculations show that neutrino production and scattering rate are altered by the nuclear interactions and that these modifications have important implications for nucleosynthesis and terrestrial neutrino detection. The calculation of neutrino rates in dense matter are difficult because nucleons in the dense matter are strongly coupled. A neutrino interacts with several nucleons and the quantum interference between scattering off different nucleons depends on the nature of correlations between them in dense matter. To describe these correlations we used analytic methods based on mean field theory and hydrodynamics, and computational methods such as Quantum Monte Carlo. We found that due to nuclear effects neutrino production rates at relevant temperatures are enhanced, and that electron neutrinos are more easily absorbed than anti-electron neutrinos in dense matter. The latter, was shown to favor synthesis of heavy neutron-rich elements in the supernova.

  14. Emulsion chamber with big radiation length for detecting neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Asratyan, A. E.; Davidenko, G. V.; Dolgolenko, A. G.; Kaftanov, V. S.; Kubantsev, M. A.; Verebryusov, V. S.

    2000-08-01

    A conceptual scheme of a hybrid-emulsion spectrometer for investigating various channels of neutrino oscillations is proposed. The design emphasizes detection of τ leptons by detached vertices, reliable identification of electrons, and good spectrometry for all charged particles and photons. A distributed target is formed by layers of low- Z material, emulsion-plastic-emulsion sheets, and air gaps in which τ decays are detected. The tracks of charged secondaries, including electrons, are momentum-analyzed by curvature in magnetic field using hits in successive thin layers of emulsion. The τ leptons are efficiently detected in all major decay channels, including τ-→ e-νν¯. The performance of a model spectrometer, that contains 3 t of nuclear emulsion and 20 t of passive material, is estimated for different experimental environments. When irradiated by the ν μ beam of a proton accelerator over a medium baseline of ˜1 km/ GeV, the spectrometer will efficiently detect either the ν μ→ν τ or the ν μ→ν e transitions in the mass-difference region of Δm 2˜1 eV2, as suggested by the results of LSND. When exposed to the neutrino beam of a muon storage ring over a long baseline of < L/ Eν>˜10- 20 km/ GeV, the model detector will efficiently probe the entire pattern of neutrino oscillations in the region Δ m2˜10 -2- 10 -3 eV2, as suggested by the data on atmospheric neutrinos.

  15. Precision Measurement of Neutrino Oscillation Parameters with KamLAND

    SciTech Connect

    O'Donnell, Thomas

    2011-12-01

    This dissertation describes a measurement of the neutrino oscillation parameters m2 21, θ12 and constraints on θ13 based on a study of reactor antineutrinos at a baseline of ~ 180 km with the KamLAND detector. The data presented here was collected between April 2002 and November 2009, and amounts to a total exposure of 2.64 ± 0.07 × 1032 proton-years. For this exposure we expect 2140 ± 74(syst) antineutrino candidates from reactors, assuming standard model neutrino behavior, and 350±88(syst) candidates from background. The number observed is 1614. The ratio of background-subtracted candidates observed to expected is (NObs - NBkg)/ (NExp) = 0.59 ± 0.02(stat) ± 0.045(syst) which confirms reactor neutrino disappearance at greater than 5σ significance. Interpreting this deficit as being due to neutrino oscillation, the best-fit oscillation parameters from a three-flavor analysis are m2 21= 7.60+0.20 -0.19×10-5eV2, θ12 = 32.5 ± 2.9 degrees and sin2 θ13 = 0.025+0.035 -0.035, the 95% confidence-level upper limit on sin2 θ13 is sin2 θ13 < 0.083. Assuming CPT invariance, a combined analysis of KamLAND and solar neutrino data yields best-fit values: m2 21 = 7.60+0.20 -0.20 × 10-5eV2, θ12 = 33.5+1.0 -1.1 degrees, and sin2 θ13 = 0.013 ± 0.028 or sin2 θ13 < 0.06 at the 95% confidence level.

  16. Solar neutrino physics with low-threshold dark matter detectors

    NASA Astrophysics Data System (ADS)

    Billard, J.; Strigari, L. E.; Figueroa-Feliciano, E.

    2015-05-01

    Dark matter detectors will soon be sensitive to Solar neutrinos via two distinct channels: coherent neutrino-nucleus and neutrino-electron elastic scatterings. We establish an analysis method for extracting Solar model properties and neutrino properties from these measurements, including the possible effects of sterile neutrinos which have been hinted at by some reactor experiments and cosmological measurements. Even including sterile neutrinos, through the coherent scattering channel, a 1 ton-year exposure with a low-threshold background free Germanium detector could improve on the current measurement of the normalization of the B 8 Solar neutrino flux down to 3% or less. Combining with the neutrino-electron elastic scattering data will provide constraints on both the high- and low-energy survival probability and will improve on the uncertainty on the active-to-sterile mixing angle by a factor of 2. This sensitivity to active-to-sterile transitions is competitive and complementary to forthcoming dedicated short baseline sterile neutrino searches with nuclear decays. Finally, we show that such solar neutrino physics potentials can be reached as long as the signal-to-noise ratio is better than 0.1.

  17. Observing supernova neutrino light curve in future dark matter detectors

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sovan; Bhattacharjee, Pijushpani; Kar, Kamales

    2014-01-01

    The possibility of observing supernova (SN) neutrinos through the process of coherent elastic neutrino-nucleus scattering (CENNS) in future ton scale detectors designed primarily for direct detection of dark matter is investigated. In particular, we focus on the possibility of distinguishing the various phases of the SN neutrino emission. The neutrino emission rates from the recent long-term Basel/Darmstadt simulations are used to calculate the expected event rates. The recent state-of-the-art SN simulations predict closer fluxes among different neutrino flavors and lower average energies compared to the earlier simulation models. The estimated total event rates are found to be typically a factor of 2 lower than those predicted using older simulation models. We find that future 1-ton class Xe detectors will be able to detect neutrinos from a SN at a distance of 10 kpc provided they have relatively low nuclear recoil energy thresholds of ≲1 keV. At the same time, with an optimistic threshold of ˜1 keV, demarcating the neutrinos associated with the accretion phase of a SN at 10 kpc from the Earth will require 10-ton class Xe detectors, while distinguishing the neutrinos associated with the neutronization burst phase of the explosion would typically require several tens of ton detectors. We also comment on the possibility of studying the properties of nonelectron flavor neutrinos from the CENNS of SN neutrinos.

  18. Overview of the present status and challenges of neutrino oscillation physics

    SciTech Connect

    Mocioiu, Irina

    2012-11-20

    This is an overview of the current status of neutrino oscillation physics, including atmospheric, solar, reactor and accelerator neutrino experiments. After summarizing our present understanding of all data, I discuss the open questions and how they might be addressed in the future. I also discuss how neutrinos can be used to learn about new physics and astrophysics.

  19. The case for mixed dark matter from sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Lello, Louis; Boyanovsky, Daniel

    2016-06-01

    Sterile neutrinos are SU(2) singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the cosmological production of heavy neutrinos via standard model charged and neutral current vertices under a minimal set of assumptions: i) the mass basis contains a hierarchy of heavy neutrinos, ii) these have very small mixing angles with the active (flavor) neutrinos, iii) standard model particles, including light (active-like) neutrinos are in thermal equilibrium. If kinematically allowed, the same weak interaction processes that produce active-like neutrinos also produce the heavier species. We introduce the quantum kinetic equations that describe their production, freeze out and decay and discuss the various processes that lead to their production in a wide range of temperatures assessing their feasibility as dark matter candidates. The final distribution function at freeze-out is a mixture of the result of the various production processes. We identify processes in which finite temperature collective excitations may lead to the production of the heavy species. As a specific example, we consider the production of heavy neutrinos in the mass range Mh lesssim 140 MeV from pion decay shortly after the QCD crossover including finite temperature corrections to the pion form factors and mass. We consider the different decay channels that allow for the production of heavy neutrinos showing that their frozen distribution functions exhibit effects from ``kinematic entanglement'' and argue for their viability as mixed dark matter candidates. We discuss abundance, phase space density and stability constraints and argue that heavy neutrinos with lifetime τ> 1/H0 freeze out of local thermal equilibrium, and conjecture that those with lifetimes τ ll 1/H0 may undergo cascade decay into lighter DM candidates and/or inject non-LTE neutrinos into the cosmic neutrino background. We provide a

  20. The Effect of Spontaneous Collapses on Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Donadi, Sandro; Bassi, Angelo; Ferialdi, Luca; Curceanu, Catalina

    2013-09-01

    We compute the effect of collapse models on neutrino oscillations. The effect of the collapse is to modify the evolution of the spatial part of the wave function and we will show that this indirectly amounts to a change on the flavor components. For the analysis we use the mass proportional CSL model, and perform the calculation to second order perturbation theory. As we will show, the CSL effect is very small—mainly due to the very small mass of neutrinos—and practically undetectable.

  1. Exploring flavor-dependent long-range forces in long-baseline neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sabya Sachi; Dasgupta, Arnab; Agarwalla, Sanjib Kumar

    2015-12-01

    The Standard Model gauge group can be extended with minimal matter content by introducing anomaly free U(1) symmetry, such as L e - L μ or L e - L τ . If the neutral gauge boson corresponding to this abelian symmetry is ultra-light, then it will give rise to flavor-dependent long-range leptonic force, which can have significant impact on neutrino oscillations. For an instance, the electrons inside the Sun can generate a flavor-dependent long-range potential at the Earth surface, which can suppress the ν μ → ν e appearance probability in terrestrial experiments. The sign of this potential is opposite for anti-neutrinos, and affects the oscillations of (anti-)neutrinos in different fashion. This feature invokes fake CP-asymmetry like the SM matter effect and can severely affect the leptonic CP-violation searches in long-baseline experiments. In this paper, we study in detail the possible impacts of these long-range flavor-diagonal neutral current interactions due to L e - L μ symmetry, when (anti-)neutrinos travel from Fermilab to Homestake (1300 km) and CERN to Pyhäsalmi (2290 km) in the context of future high-precision superbeam facilities, DUNE and LBNO respectively. If there is no signal of long-range force, DUNE (LBNO) can place stringent constraint on the effective gauge coupling α eμ < 1.9 × 10-53 (7.8 × 10-54) at 90% C.L., which is almost 30 (70) times better than the existing bound from the Super-Kamiokande experiment. We also observe that if α eμ ≥ 2 × 10-52, the CP-violation discovery reach of these future facilities vanishes completely. The mass hierarchy measurement remains robust in DUNE (LBNO) if α eμ < 5 × 10-52 (10-52).

  2. Experimental evidence of electron neutrino oscillations and validation of MSW-LMA model with Borexino

    NASA Astrophysics Data System (ADS)

    Avanzini, M. Buizza

    2011-04-01

    We report the real time measurements of 7Be and 8B solar neutrino fluxes performed with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. The achievement of these measurements was possible thanks to the excellent levels of the radiopurity reached. The measurement of the 7Be in real time is the first direct measurements of the survival probability for solar electron neutrinos in the vacuum region. For 8B we reached a threshold energy of 3MeV which is the lowest achieved so far in real time. For the first time, the same apparatus can measure two different oscillation regions (vacuum-driven and matter-enhanced) predicted by the MSW-LMA model. Borexino also quotes the ratio between the survival probabilities, corresponding to 1.93 ± 0.75, and validates the presence of the transition region between the two oscillation regimes, according to the MSW-LMA solution.In addition, a preliminary result on the Day-Night Asymmetry (ADN) for the 7Be neutrino flux is presented and corresponds to 0.007 ± 0.073. This measurement makes Borexino able to give once more an independent confirmation of the MSW-LMA solution.

  3. Neutrino-nucleus interaction models and their impact on oscillation analyses

    NASA Astrophysics Data System (ADS)

    Coloma, P.; Huber, P.; Jen, C.-M.; Mariani, C.

    2014-04-01

    In neutrino oscillation experiments, neutrino interactions at the detector are simulated using event generators which attempt to reflect our understanding of nuclear physics. We study the impact of different neutrino interactions and nuclear models on the determination of neutrino oscillation parameters. We use two independent neutrino event generators, Generates Events for Neutrino Interaction Experiments (GENIE) 2.8.0 and Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) 2.6, and apply them to a setup with a conventional neutrino beam aiming at a water Čerenkov detector, for which only the charged-current quasielastic-like sample is selected. Subsequently, we perform a fit to the oscillation parameters in the νμ disappearance channel.

  4. Los Alamos Science, Number 25 -- 1997: Celebrating the Neutrino

    DOE R&D Accomplishments Database

    Cooper, N. G. ed.

    1997-01-01

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  5. Los Alamos Science, Number 25 -- 1997: Celebrating the neutrino

    SciTech Connect

    Cooper, N.G.

    1997-12-31

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  6. Dirac neutrino mass from a neutrino dark matter model for the galaxy cluster Abell 1689

    NASA Astrophysics Data System (ADS)

    Nieuwenhuizen, Theodorus Maria

    2016-03-01

    The dark matter in the galaxy cluster Abell 1689 is modelled as an isothermal sphere of neutrinos. New data on the 2d mass density allow an accurate description of its core and halo. The model has no “missing baryon problem” and beyond 2.1 Mpc the baryons have the cosmic mass abundance. Combination of cluster data with the cosmic dark matter fraction - here supposed to stem from the neutrinos - leads to a solution of the dark matter riddle by left and right handed neutrinos with mass (1.861 ± 0.016)h 70 -2eV/c 2. The thus far observed absence of neutrinoless double beta decay points to (quasi-) Dirac neutrinos: uncharged electrons with different flavour and mass eigenbasis, as for quarks. Though the cosmic microwave background spectrum is matched up to some 10% accuracy only, the case is not ruled out because the plasma phase of the early Universe may be turbulent.

  7. Physics from solar neutrinos in dark matter direct detection experiments

    NASA Astrophysics Data System (ADS)

    Cerdeño, David G.; Fairbairn, Malcolm; Jubb, Thomas; Machado, Pedro A. N.; Vincent, Aaron C.; Bœhm, Céline

    2016-05-01

    The next generation of dark matter direct detection experiments will be sensitive to both coherent neutrino-nucleus and neutrino-electron scattering. This will enable them to explore aspects of solar physics, perform the lowest energy measurement of the weak angle sin2 θ W to date, and probe contributions from new theories with light mediators. In this article, we compute the projected nuclear and electron recoil rates expected in several dark matter direct detection experiments due to solar neutrinos, and use these estimates to quantify errors on future measurements of the neutrino fluxes, weak mixing angle and solar observables, as well as to constrain new physics in the neutrino sector. Our analysis shows that the combined rates of solar neutrino events in second generation experiments (SuperCDMS and LZ) can yield a measurement of the pp flux to 2.5% accuracy via electron recoil, and slightly improve the 8B flux determination. Assuming a low-mass argon phase, projected tonne-scale experiments like DARWIN can reduce the uncertainty on both the pp and boron-8 neutrino fluxes to below 1%. Finally, we use current results from LUX, SuperCDMS and CDMSlite to set bounds on new interactions between neutrinos and electrons or nuclei, and show that future direct detection experiments can be used to set complementary constraints on the parameter space associated with light mediators.

  8. Neutrino oscillations with IceCube DeepCore and PINGU

    SciTech Connect

    DeYoung, T.; Collaboration: IceCube-PINGU Collaboration

    2014-11-18

    The IceCube neutrino telescope was augmented with the DeepCore infill array, completed in the 2010/11 austral summer, to enhance its response to neutrinos below 100 GeV. At these energies, neutrino oscillation effects are visible in the flux of atmospheric neutrinos traversing path lengths comparable to the Earth's diameter. Initial measurements of muon neutrino disappearance parameters using data from DeepCore are presented, as well as an estimate of potential future precision. In addition, plans for a Precision IceCube Next Generation Upgrade (PINGU), which could permit determination of the neutrino mass hierarchy within the coming decade, are discussed.

  9. SOLAR NEUTRINO PHYSICS: SENSITIVITY TO LIGHT DARK MATTER PARTICLES

    SciTech Connect

    Lopes, Ilidio; Silk, Joseph E-mail: ilopes@uevora.pt

    2012-06-20

    Neutrinos are produced in several neutrino nuclear reactions of the proton-proton chain and carbon-nitrogen-oxygen cycle that take place at different radii of the Sun's core. Hence, measurements of solar neutrino fluxes provide a precise determination of the local temperature. The accumulation of non-annihilating light dark matter particles (with masses between 5 GeV and 16 GeV) in the Sun produces a change in the local solar structure, namely, a decrease in the central temperature of a few percent. This variation depends on the properties of the dark matter particles, such as the mass of the particle and its spin-independent scattering cross-section on baryon-nuclei, specifically, the scattering with helium, oxygen, and nitrogen among other heavy elements. This temperature effect can be measured in almost all solar neutrino fluxes. In particular, by comparing the neutrino fluxes generated by stellar models with current observations, namely {sup 8}B neutrino fluxes, we find that non-annihilating dark matter particles with a mass smaller than 10 GeV and a spin-independent scattering cross-section with heavy baryon-nuclei larger than 3 Multiplication-Sign 10{sup -37} cm{sup -2} produce a variation in the {sup 8}B neutrino fluxes that would be in conflict with current measurements.

  10. Summary: Neutrinos and nonaccelerator physics

    SciTech Connect

    Hoffman, C.M.

    1991-01-01

    This paper contains brief synopsis of the following major topics discussed in the neutrino and nonaccelerator parallel sessions: dark matter; neutrino oscillations at accelerators and reactors; gamma-ray astronomy; double beta decay; solar neutrinos; and the possible existence of a 17-KeV neutrino. (LSP)

  11. Asymmetric dark matter and effective number of neutrinos

    NASA Astrophysics Data System (ADS)

    Kitabayashi, Teruyuki; Kurosawa, Yoshihiro

    2016-02-01

    We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos Neff at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter χ couples more strongly to the neutrinos ν than to the photons γ and electrons e-, Γχ γ ,χ e≪Γχ ν , or Γχ γ ,χ e≫Γχ ν, the lower mass limit on the asymmetric dark matter is about 18 MeV for Neff≃3.0 .

  12. Consistency of WIMP Dark Matter as radiative neutrino mass messenger

    NASA Astrophysics Data System (ADS)

    Merle, Alexander; Platscher, Moritz; Rojas, Nicolás; Valle, José W. F.; Vicente, Avelino

    2016-07-01

    The scotogenic scenario provides an attractive approach to both Dark Matter and neutrino mass generation, in which the same symmetry that stabilises Dark Matter also ensures the radiative seesaw origin of neutrino mass. However the simplest scenario may suffer from inconsistencies arising from the spontaneous breaking of the underlying ℤ 2 symmetry. Here we show that the singlet-triplet extension of the simplest model naturally avoids this problem due to the presence of scalar triplets neutral under the ℤ 2 which affect the evolution of the couplings in the scalar sector. The scenario offers good prospects for direct WIMP Dark Matter detection through the nuclear recoil method.

  13. Indirect Search for Dark Matter with the ANTARES Neutrino Telescope

    SciTech Connect

    Loucatos, S.

    2010-02-10

    One of the goals of the ANTARES underwater neutrino telescope is the search for dark matter in the universe. In this paper the first results on the search for dark matter in the Sun with ANTARES in its 5 line configuration, as well as sensitivity studies with the full ANTARES detector are presented.

  14. Properties of resonantly produced sterile neutrino dark matter subhaloes

    NASA Astrophysics Data System (ADS)

    Horiuchi, Shunsaku; Bozek, Brandon; Abazajian, Kevork N.; Boylan-Kolchin, Michael; Bullock, James S.; Garrison-Kimmel, Shea; Onorbe, Jose

    2016-03-01

    The anomalous 3.55 keV X-ray line recently detected towards a number of massive dark matter objects may be interpreted as the radiative decays of 7.1 keV mass sterile neutrino dark matter. Depending on its parameters, the sterile neutrino can range from cold to warm dark matter with small-scale suppression that differs in form from commonly adopted thermal warm dark matter. Here, we numerically investigate the subhalo properties for 7.1 keV sterile neutrino dark matter produced via the resonant Shi-Fuller mechanism. Using accurate matter power spectra, we run cosmological zoom-in simulations of a Milky Way-sized halo and explore the abundance of massive subhaloes, their radial distributions, and their internal structure. We also simulate the halo with thermal 2.0 keV warm dark matter for comparison and discuss quantitative differences. We find that the resonantly produced sterile neutrino model for the 3.55 keV line provides a good description of structures in the Local Group, including the number of satellite dwarf galaxies and their radial distribution, and largely mitigates the too-big-to-fail problem. Future searches for satellite galaxies by deep surveys, such as the Dark Energy Survey, Large Synoptic Survey Telescope, and Wide Field Infrared Survey Telescope, will be a strong direct test of warm dark matter scenarios.

  15. On the Degeneracies of the Mass-Squared Differences for Three-Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Latimer, D. C.; Ernst, D. J.

    Using an algebraic formulation, we explore two well-known degeneracies involving the mass-squared differences for three-neutrino oscillations assuming CP symmetry is conserved. For vacuum oscillation, we derive the expression for the mixing angles that permit invariance under the interchange of two mass-squared differences. This symmetry is most easily expressed in terms of an ascending mass order. This can be used to reduce the parameter space by one half in the absence of the MSW effect. For oscillations in matter, we derive within our formalism the known approximate degeneracy between the standard and inverted mass hierarchies in the limit of vanishing θ13. This is done with a mass ordering that permits the map Δ31↦-Δ31. Our techniques allow us to translate mixing angles in this mass order convention into their values for the ascending order convention. Using this dictionary, we demonstrate that the vacuum symmetry and the approximate symmetry invoked for oscillations in matter are distinctly different.

  16. Exotic charges, multicomponent dark matter and light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Heeck, Julian; Zhang, He

    2013-05-01

    Generating small sterile neutrino masses via the same seesaw mechanism that suppresses active neutrino masses requires a specific structure in the neutral fermion mass matrix. We present a model where this structure is enforced by a new U(1)' gauge symmetry, spontaneously broken at the TeV scale. The additional fermions necessary for anomaly cancellation need to carry exotic charges in order not to spoil the neutrino structure and turn out to form multicomponent cold dark matter. The active-sterile mixing then connects the new particles and the Standard Model — opening a new portal in addition to the usual Higgs- and kinetic-mixing portals — which leads to dark matter annihilation almost exclusively into neutrinos.

  17. The matter-neutrino resonance around thick disks

    NASA Astrophysics Data System (ADS)

    Deaton, Michael

    2016-03-01

    We are studying neutrino flavor transformations in typical neutron star merger environments. Here a dominance of νe over νe fluxes introduces transformation behaviors qualitatively different from those seen in supernovae. Discovered in thin disk models, the matter neutrino resonance (MNR) may behave differently around thick disks, or not appear at all. I'll present what we have learned about the MNR using a phenomenological model motivated by hydrodynamical simulations of post-merger disks. JINA-CEE.

  18. Relativistic Wigner function approach to neutrino propagation in matter

    NASA Astrophysics Data System (ADS)

    Sirera, M.; Pérez, A.

    1999-06-01

    In this work we study the propagation of massive Dirac neutrinos in matter with flavor mixing, using statistical techniques based on relativistic Wigner functions. First, we consider neutrinos in equilibrium within the Hartree approximation, and obtain the corresponding dispersion relations and effective masses. After this, we analyze the same system out of equilibrium. We verify that, under the appropriate physical conditions, the well-known equations for the MSW effect are recovered.

  19. Tight bonds between sterile neutrinos and dark matter

    SciTech Connect

    Bringmann, Torsten; Hasenkamp, Jasper; Kersten, Jörn E-mail: Jasper.Hasenkamp@nyu.edu

    2014-07-01

    Despite the astonishing success of standard ΛCDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both cold dark matter (DM) and sterile neutrinos are charged under a new U(1){sub X} gauge interaction. The resulting DM self-interactions resolve the tension with the observed abundances and internal density structures of dwarf galaxies. At the same time, the sterile neutrinos can account for both the small hot DM component favored by cosmological observations and the neutrino anomalies found in short-baseline experiments.

  20. Radiative model of neutrino mass with neutrino interacting MeV dark matter

    NASA Astrophysics Data System (ADS)

    Arhrib, Abdesslam; Bœhm, Céline; Ma, Ernest; Yuan, Tzu-Chiang

    2016-04-01

    We consider the radiative generation of neutrino mass through the interactions of neutrinos with MeV dark matter. We construct a realistic renormalizable model with one scalar doublet (in additional to the standard model doublet) and one complex singlet together with three light singlet Majorana fermions, all transforming under a dark U(1)D symmetry which breaks softly to Z2. We study in detail the scalar sector which supports this specific scenario and its rich phenomenology.

  1. Some uncertainties of neutrino oscillation effect in the NOνA experiment

    NASA Astrophysics Data System (ADS)

    Kolupaeva, Lyudmila D.; Kuzmin, Konstantin S.; Petrova, Olga N.; Shandrov, Igor M.

    2016-04-01

    Uncertainties related to the effect of neutrino coherent forward scattering in Earth’s matter (MSW mechanism) and with the cross-sections of quasi-elastic (QE) neutrino scattering on nuclear targets of the NOνA detectors are studied. The NOνA sensitivity to the neutrino mass hierarchy and the CP violating phase is discussed.

  2. Neutrino-Antineutrino Mass Splitting in the Standard Model: Neutrino Oscillation and Baryogenesis

    NASA Astrophysics Data System (ADS)

    Fujikawa, Kazuo; Tureanu, Anca

    By adding a neutrino mass term to the Standard Model, which is Lorentz and SU(2) × U(1) invariant but nonlocal to evade CPT theorem, it is shown that nonlocality within a distance scale of the Planck length, that may not be fatal to unitarity in generic effective theory, can generate the neutrino-antineutrino mass splitting of the order of observed neutrino mass differences, which is tested in oscillation experiments, and non-negligible baryon asymmetry depending on the estimate of sphaleron dynamics. The one-loop order induced electron-positron mass splitting in the Standard Model is shown to be finite and estimated at ˜ 10-20 eV, well below the experimental bound < 10-2 eV. The induced CPT violation in the K-meson in the Standard Model is expected to be even smaller and well below the experimental bound |m_{K} - m_{bar{K}}| < 0.44 × 10^{-18} GeV.

  3. Determining neutrino oscillation parameters from atmospheric muon neutrino disappearance with three years of IceCube DeepCore data

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Brunner, J.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Classen, L.; Clevermann, F.; Coenders, S.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eichmann, B.; Eisch, J.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Felde, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Gier, D.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grant, D.; Gretskov, P.; Groh, J. C.; Groß, A.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Hebecker, D.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hellwig, D.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huang, F.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Jurkovic, M.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Koob, A.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kriesten, A.; Krings, K.; Kroll, G.; Kroll, M.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larsen, D. T.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Lünemann, J.; Madsen, J.; Maggi, G.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meli, A.; Meures, T.; Miarecki, S.; Middell, E.; Middlemas, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Palczewski, T.; Paul, L.; Penek, Ö.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Pütz, J.; Quinnan, M.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Rees, I.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Riedel, B.; Robertson, S.; Rodrigues, J. P.; Rongen, M.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Sander, H.-G.; Sandroos, J.; Santander, M.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Shanidze, R.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stanisha, N. A.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Tosi, D.; Tselengidou, M.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Vandenbroucke, J.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallraff, M.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Whitehorn, N.; Wichary, C.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.; IceCube Collaboration

    2015-04-01

    We present a measurement of neutrino oscillations via atmospheric muon neutrino disappearance with three years of data of the completed IceCube neutrino detector. DeepCore, a region of denser IceCube instrumentation, enables the detection and reconstruction of atmospheric muon neutrinos between 10 and 100 GeV, where a strong disappearance signal is expected. The IceCube detector volume surrounding DeepCore is used as a veto region to suppress the atmospheric muon background. Neutrino events are selected where the detected Cherenkov photons of the secondary particles minimally scatter, and the neutrino energy and arrival direction are reconstructed. Both variables are used to obtain the neutrino oscillation parameters from the data, with the best fit given by Δ m322=2.72-0.20+0.19×10-3 eV2 and sin2θ23=0.53-0.12+0.09 (normal mass ordering assumed). The results are compatible, and comparable in precision, to those of dedicated oscillation experiments.

  4. Synchronization versus decoherence of neutrino oscillations at intermediate densities

    SciTech Connect

    Raffelt, Georg G.; Tamborra, Irene

    2010-12-15

    We study collective oscillations of a two-flavor neutrino system with arbitrary but fixed density. In the vacuum limit, modes with different energies quickly dephase (kinematical decoherence), whereas in the limit of infinite density they lock to each other (synchronization). For intermediate densities, we find different classes of solutions. There is always a phase transition in the sense of partial synchronization occurring only above a density threshold. For small mixing angles, partial or complete decoherence can be induced by a parametric resonance, introducing a new time scale to the problem, the final outcome depending on the spectrum and mixing angle. We derive an analytic relation that allows us to calculate the late-time degree of coherence based on the spectrum alone.

  5. Recent Results from the K2K - Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Hill, James E.

    2002-12-01

    The K2K Long-Baseline neutrino oscillation experiment has been aquiring data since mid-1999 and has analysed those up to July of 2001. Fifty-six fully contained events are observed in the fiducial volume of the far detector where 80.6-8.0+7.3 are expected based partly on measurements near the beam production point. There is virtually no background for the contained event search. The methods established in this experiment are crucial for operation of future similar experiments to probe the nature of mixing in the neutral lepton sector, a necessary step in understanding the nature of family structure and of mass itself. A brief history and a few notes about the future and direction of the field precede the description of the experiment and its results.

  6. Heavy right-handed neutrino dark matter and PeV neutrinos at IceCube

    NASA Astrophysics Data System (ADS)

    Bhupal Dev, P. S.; Kazanas, D.; Mohapatra, R. N.; Teplitz, V. L.; Zhang, Yongchao

    2016-08-01

    We discuss a simple non-supersymmetric model based on the electroweak gauge group SU(2)L × SU(2)' × U(1)B–L where the lightest of the right-handed neutrinos, which are part of the leptonic doublet of SU(2)', play the role of a long-lived unstable dark matter with mass in the multi-PeV range. We use a resonant s-channel annihilation to obtain the correct thermal relic density and relax the unitarity bound on dark matter mass. In this model, there exists a 3-body dark matter decay mode producing tau leptons and neutrinos, which could be the source for the PeV cascade events observed in the IceCube experiment. The model can be tested with more precise flavor information of the highest-energy neutrino events in future data.

  7. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    SciTech Connect

    Jen, C.-M.

    2015-10-15

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (∼ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  8. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Jen, C.-M.

    2015-10-01

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (˜ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  9. Dark matter signals at neutrino telescopes in effective theories

    SciTech Connect

    Catena, Riccardo

    2015-04-29

    We constrain the effective theory of one-body dark matter-nucleon interactions using neutrino telescope observations. We derive exclusion limits on the 28 coupling constants of the theory, exploring interaction operators previously considered in dark matter direct detection only, and using new nuclear response functions recently derived through nuclear structure calculations. We determine for what interactions neutrino telescopes are superior to current direct detection experiments, and show that Hydrogen is not the most important element in the exclusion limit calculation for the majority of the spin-dependent operators.

  10. Tachyon field non-minimally coupled to massive neutrino matter

    NASA Astrophysics Data System (ADS)

    Ahmad, Safia; Myrzakulov, Nurgissa; Myrzakulov, R.

    2016-07-01

    In this paper, we consider rolling tachyon, with steep run-away type of potentials non-minimally coupled to massive neutrino matter. The coupling dynamically builds up at late times as neutrino matter turns non-relativistic. In case of scaling and string inspired potentials, we have shown that non-minimal coupling leads to minimum in the field potential. Given a suitable choice of model parameters, it is shown to give rise to late-time acceleration with the desired equation of state.

  11. Can decaying sterile neutrinos account for all dark matter?

    NASA Astrophysics Data System (ADS)

    Chan, Man Ho

    2016-04-01

    The recent discovery of unexplained X-ray line of 3.5-3.6 keV emitted from the Perseus cluster of galaxies and M31 and the excess X-ray line of 8.7 keV emitted from the Milky Way center may indicate that dark matter would decay. In this article, I show that approximately 80 % of dark matter being 7.1 keV sterile neutrinos and 20 % of dark matter being 17.4 keV sterile neutrinos can satisfactorily explain the observed X-ray lines and account for all missing mass. No free parameter is needed in this model. This scenario is also compatible with current robust observational constraints from the matter power spectrum in large-scale structures and would alleviate the challenges faced by the existing dark matter models.

  12. WIMP dark matter and supersymmetry searches with neutrino telescopes

    NASA Astrophysics Data System (ADS)

    Fornengo, N.

    2011-01-01

    The particle physics interpretation of the missing-mass, or dark-matter, a problem of cosmological and astrophysical nature, is going to be placed under strong scrutiny in the next years. From the particle physics side, accelerator physics will deeply test theoretical ideas about new physics beyond the Standard Model, where a particle physics candidate to dark matter is often naturally obtained. From the astrophysical side, many probes are already providing a great deal of independent information on signals which can be produced by the galactic or extra-galactic dark matter. The current and new-generation experimental efforts are therefore going to place under deep scrutiny the theoretical explanations of the relevant signals. The ultimate hope is in fact to be able to disentangle a dark matter signal from the various sources of backgrounds. Neutrino telescopes are one of the prominent tools for looking at dark matter and search for a signal, the neutrino flux from Earth and Sun. In this neutrino dark matter searches share properties with both direct dark matter searches and cosmic-ray indirect dark matter searches, and therefore complement these different detection techniques.

  13. Neutrino oscillation parameter sampling with MonteCUBES

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Fernandez-Martinez, Enrique

    2010-01-01

    We present MonteCUBES ("Monte Carlo Utility Based Experiment Simulator"), a software package designed to sample the neutrino oscillation parameter space through Markov Chain Monte Carlo algorithms. MonteCUBES makes use of the GLoBES software so that the existing experiment definitions for GLoBES, describing long baseline and reactor experiments, can be used with MonteCUBES. MonteCUBES consists of two main parts: The first is a C library, written as a plug-in for GLoBES, implementing the Markov Chain Monte Carlo algorithm to sample the parameter space. The second part is a user-friendly graphical Matlab interface to easily read, analyze, plot and export the results of the parameter space sampling. Program summaryProgram title: MonteCUBES (Monte Carlo Utility Based Experiment Simulator) Catalogue identifier: AEFJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 69 634 No. of bytes in distributed program, including test data, etc.: 3 980 776 Distribution format: tar.gz Programming language: C Computer: MonteCUBES builds and installs on 32 bit and 64 bit Linux systems where GLoBES is installed Operating system: 32 bit and 64 bit Linux RAM: Typically a few MBs Classification: 11.1 External routines: GLoBES [1,2] and routines/libraries used by GLoBES Subprograms used:Cat Id ADZI_v1_0, Title GLoBES, Reference CPC 177 (2007) 439 Nature of problem: Since neutrino masses do not appear in the standard model of particle physics, many models of neutrino masses also induce other types of new physics, which could affect the outcome of neutrino oscillation experiments. In general, these new physics imply high-dimensional parameter spaces that are difficult to explore using classical methods such as multi-dimensional projections and minimizations, such as those

  14. Predictive model for radiatively induced neutrino masses and mixings with dark matter.

    PubMed

    Gustafsson, Michael; No, Jose M; Rivera, Maximiliano A

    2013-05-24

    A minimal extension of the standard model to naturally generate small neutrino masses and provide a dark matter candidate is proposed. The dark matter particle is part of a new scalar doublet field that plays a crucial role in radiatively generating neutrino masses. The symmetry that stabilizes the dark matter also suppresses neutrino masses to appear first at three-loop level. Without the need of right-handed neutrinos or other very heavy new fields, this offers an attractive explanation of the hierarchy between the electroweak and neutrino mass scales. The model has distinct verifiable predictions for the neutrino masses, flavor mixing angles, colliders, and dark matter signals. PMID:23745861

  15. Latest results on atmospheric neutrino oscillations from IceCube/DeepCore

    NASA Astrophysics Data System (ADS)

    de André, J. P. A. M.; IceCube Collaboration

    2016-05-01

    The IceCube Neutrino Observatory, located at the South Pole, is the world’s largest neutrino detector. DeepCore, the low energy extension for IceCube, with a threshold of about ten GeV is well suited to study neutrino oscillations using neutrinos produced in the Earth’s atmosphere and traveling distances as large as the Earth’s diameter before being detected. Using these neutrinos DeepCore makes measurements of the neutrino oscillation parameters θ23 and |Δm 2 32| with precisions approaching that of dedicated experiments, and based on preliminary studies these results can still be further improved. These new studies as well as the current results obtained in DeepCore are discussed here.

  16. A search for oscillation of atmospheric neutrinos with the IMB detector

    NASA Astrophysics Data System (ADS)

    Gajewski, W.

    1992-07-01

    Neutrino oscillations have been studied using a flux of atmospheric neutrinos and the IMB water C¯erenkov detector. The study is based on: 1) a sample of 935 events in the detector volume during 7.7 kton-yrs exposure. About 70% of events have a single track which allows identification of the parent neutrino flavor. 2) a sample of 593 up-going muon tracks from neutrino interactions in rock below the detector. These studies are sensitive to δm2 down to 10-4eV2 and sin2(2θ) > 0.4, a region unexplored in previous experiments. Future plans of long baseline neutrino oscillation studies using the IMB detector and neutrinos from artificial sources are described. They include νe from a power reactor 13 km from the detector and νμ produced by the Main Injector at Fermilab at a distance of 570 km.

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

    SciTech Connect

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

    2001-07-01

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

  18. Neutrino Coannihilation on Dark-Matter Relics?

    SciTech Connect

    Barenboim, Gabriela; Mena Requejo, Olga; Quigg, Chris; /Fermilab

    2006-04-01

    High-energy neutrinos may resonate with relic background neutralinos to form short-lived sneutrinos. In some circumstances, the decay chain that leads back to the lightest supersymmetric particle would yield few-GeV gamma rays or charged-particle signals. Although resonant coannihilation would occur at an appreciable rate in our galaxy, the signal in any foreseeable detector is unobservably small.

  19. Probing neutrino oscillations in supersymmetric models at the Large Hadron Collider

    SciTech Connect

    Campos, F. de; Eboli, O. J. P.; Hirsch, M.; Valle, J. W. F.; Porod, W.

    2010-10-01

    The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation.

  20. On possible tachyonic state of neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Makukov, Maxim A.; Mychelkin, Eduard G.; Saveliev, Vladimir L.

    2016-03-01

    We revive the historically first neutrino dark matter model, but with an additional assumption that neutrinos might exist in tachyonic almost sterile states. To this end we propose a group-theoretical algorithm for the description of tachyons. The key point is that we employ a distinct tachyon Lorentz group with another (superluminal) parametrization which does not require traditional introduction of imaginary masses and negative energies, and therefore does not lead to violation of causality and unitarity. Our dark matter model represents effectively scalar tachyonic neutrino-antineutrino conglomerate. Distributed all over the universe, such fluid behaves as stable isothermal/stiff medium which produces somewhat denser regions (‘smoothed halos’) around galaxies and clusters. It is shown to be consistent with observational effects (galactic rotation curves).

  1. Monoenergetic neutrinos from dark matter annihilation: Issues of exposure

    NASA Astrophysics Data System (ADS)

    Kumar, Jason

    2016-06-01

    We consider searches for dark matter annihilation in the Sun resulting in monoenergetic neutrinos, produced either directly or through the decay of stopped pions and kaons. We find that this strategy is very successful at increasing the signal-to-background ratio, but that current experiments may be signal limited. We discuss the exposures need to fully exploit this search strategy.

  2. Neutrino physics with dark matter experiments and the signature of new baryonic neutral currents

    SciTech Connect

    Pospelov, Maxim

    2011-10-15

    New neutrino states {nu}{sub b}, sterile under the standard model interactions, can be coupled to baryons via the isoscalar vector currents that are much stronger than the standard model weak interactions. If some fraction of solar neutrinos oscillate into {nu}{sub b} on their way to Earth, the coherently enhanced elastic {nu}{sub b}-nucleus scattering can generate a strong signal in the dark matter detectors. For the interaction strength a few hundred times stronger than the weak force, the elastic {nu}{sub b}-nucleus scattering via new baryonic currents may account for the existing anomalies in the direct detection dark matter experiments at low recoil. We point out that for solar-neutrino energies, the baryon-current-induced inelastic scattering is suppressed, so that the possible enhancement of a new force is not in conflict with signals at dedicated neutrino detectors. We check this explicitly by calculating the {nu}{sub b}-induced deuteron breakup, and the excitation of a 4.4 MeV {gamma} line in {sup 12}C. A stronger-than-weak force coupled to the baryonic current implies the existence of a new Abelian gauge group U(1){sub B} with a relatively light gauge boson.

  3. Neutrino physics with dark matter experiments and the signature of new baryonic neutral currents

    NASA Astrophysics Data System (ADS)

    Pospelov, Maxim

    2011-10-01

    New neutrino states νb, sterile under the standard model interactions, can be coupled to baryons via the isoscalar vector currents that are much stronger than the standard model weak interactions. If some fraction of solar neutrinos oscillate into νb on their way to Earth, the coherently enhanced elastic νb-nucleus scattering can generate a strong signal in the dark matter detectors. For the interaction strength a few hundred times stronger than the weak force, the elastic νb-nucleus scattering via new baryonic currents may account for the existing anomalies in the direct detection dark matter experiments at low recoil. We point out that for solar-neutrino energies, the baryon-current-induced inelastic scattering is suppressed, so that the possible enhancement of a new force is not in conflict with signals at dedicated neutrino detectors. We check this explicitly by calculating the νb-induced deuteron breakup, and the excitation of a 4.4 MeV γ line in C12. A stronger-than-weak force coupled to the baryonic current implies the existence of a new Abelian gauge group U(1)B with a relatively light gauge boson.

  4. NEUTRINOS OSCILLATIONS WITH LONG-BASE-LINE BEAMS:. Past, Present and very near Future

    NASA Astrophysics Data System (ADS)

    Stanco, L.

    2011-03-01

    We overview the status of the studies on neutrino oscillations with accelerators at the present running experiments. Past and present results enlighten the path towards the observation of massive neutrinos and the settling of their oscillations. The very near future may still have addiction from the outcome of the on-going experiments. OPERA is chosen as a relevant example justified by the very recent results released.

  5. Future sensitivity of neutrino telescopes to dark matter annihilations from the cosmic diffuse neutrino signal

    NASA Astrophysics Data System (ADS)

    Moliné, Ángeles; Ibarra, Alejandro; Palomares-Ruiz, Sergio

    2015-06-01

    Cosmological observations and cold dark matter N-body simulations indicate that our Universe is populated by numerous halos, where dark matter particles annihilate, potentially producing Standard Model particles. In this paper we calculate the contribution to the diffuse neutrino background from dark matter annihilations in halos at all redshifts and we estimate the future sensitivity to the annihilation cross section of neutrino telescopes such as IceCube or ANTARES. We consider various parametrizations to describe the internal halo properties and for the halo mass function in order to bracket the theoretical uncertainty in the limits from the modeling of the cosmological annihilation flux. We find that observations of the cosmic diffuse neutrino flux at large angular distances from the galactic center lead to constraints on the dark matter annihilation cross section which are complementary to (and for some extrapolations of the astrophysical parameters, better than) those stemming from observations of the Milky Way halo, especially for neutrino telescopes not pointing directly to the Milky Way center, as is the case of IceCube.

  6. Propagation of high-energy neutrinos in a background of ultralight scalar dark matter

    NASA Astrophysics Data System (ADS)

    Reynoso, Matías M.; Sampayo, Oscar A.

    2016-09-01

    If high-energy neutrinos propagate in a background of ultralight scalar field particles of dark matter (mφ ∼10-23 eV), neutrino-dark matter interactions can play a role and affect the neutrino flux. In this work we analyse this effect using transport equations that account for the neutrino regeneration as well as absorption, and we consider the neutrino flux propagation in the extragalactic medium and also through the galactic halo of dark matter. We show the results for the final flux to arrive on Earth for different cases of point and diffuse neutrino fluxes. We conclude that this type of neutrino interactions with ultralight scalar particles as dark matter can yield very different results in the neutrino flux and in the flavor ratios that can be measured in neutrino detectors such as IceCube.

  7. Quantum-gravity decoherence effects in neutrino oscillations: Expected constraints from CNGS and J-PARC

    SciTech Connect

    Mavromatos, Nick E.; Sarkar, Sarben; Meregaglia, Anselmo; Sakharov, Alexander S.

    2008-03-01

    Quantum decoherence, the evolution of pure states into mixed states, may be a feature of quantum-gravity models. In most cases, such models lead to fewer neutrinos of all active flavors being detected in a long-baseline experiment as compared to three-flavor standard neutrino oscillations. We discuss the potential of the CNGS and J-PARC beams in constraining models of quantum-gravity induced decoherence using neutrino oscillations as a probe. We use as much as possible model-independent parametrizations, even though they are motivated by specific microscopic models, for fits to the expected experimental data which yield bounds on quantum-gravity decoherence parameters.

  8. Spontaneous Oscillations in an Active Matter System

    NASA Astrophysics Data System (ADS)

    Hayes, Robert; Tsang, Boyce; Granick, Steve

    Active matter (which consumes energy to move about) can organize into dynamic structures more interesting than those possible at steady-state. Here we show spontaneous periodic self-assembly in a simple three-component system of water, oil phase, and surfactant at constant room temperature, with emphasis on one model system. Benchtop experiments show that liquid crystal oil droplets spontaneously and collectively oscillate like a `beating heart' for several hours; contract, relax, and subsequently re-contract in a petri dish at a rate of a few `beats' per minute. These oscillations, emergent from the cooperative interaction of the three components, are driven by the competition between positive and negative feedback processes. This illustration of feedback in action reveals a new way to program self-assembled structures to vary with time.

  9. Special Issue on "Neutrino Oscillations: Celebrating the Nobel Prize in Physics 2015" in Nuclear Physics B

    NASA Astrophysics Data System (ADS)

    Ohlsson, Tommy

    2016-07-01

    In 2015, the Nobel Prize in Physics was awarded jointly to Takaaki Kajita from the Super-Kamiokande Collaboration and Arthur B. McDonald from the SNO Collaboration "for the discovery of neutrino oscillations, which shows that neutrinos have mass". Furthermore, the Daya Bay, K2K and T2K, KamLAND, SNO, and Super-Kamiokande Collaborations shared the Fundamental Physics Breakthrough Prize the same year. In order to celebrate this successful and fruitful year for neutrino oscillations, the editors and the publisher of Nuclear Physics B decided to publish a Special Issue on neutrino oscillations. We invited prominent scientists in the area of neutrino physics that relates to neutrino oscillations to write contributions for this Special Issue, which was open to both original research articles as well as review articles. The authors of this Special Issue consist of e.g. the two Nobel Laureates, International Participants of the Nobel Symposium 129 on Neutrino Physics at Haga Slott in Enköping, Sweden (August 19-24, 2004), selected active researchers, and members from large experimental collaborations with major results in the last ten years. In total, this Special Issue consists of 28 contributions. Please note that the cover of this Special Issue contains a figure from each of the 26 contributions that have figures included.

  10. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    NASA Astrophysics Data System (ADS)

    Chen, Jiunn-Wei; Chi, Hsin-Chang; Lin, Shin-Ted; Liu, C.-P.; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

    2016-05-01

    The transition magnetic moment of a sterile neutrino can give rise to its conversion to an active neutrino through radiative decay or nonstandard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic x-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with low-threshold low-background germanium detectors, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations.

  11. Can sterile neutrinos be ruled out as warm dark matter candidates?

    PubMed

    Viel, Matteo; Lesgourgues, Julien; Haehnelt, Martin G; Matarrese, Sabino; Riotto, Antonio

    2006-08-18

    We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey Lyman-alpha flux power spectrum at 2.2neutrinos and mWDM greater than or similar to 2 keV (2sigma) for early decoupled thermal relics. If we combine this bound with the constraint derived from x-ray flux observations of the Coma cluster, we find that the allowed sterile neutrino mass is approximately 10 keV (in the standard production scenario). Adding constraints based on x-ray fluxes from the Andromeda galaxy, we find that dark matter particles cannot be sterile neutrinos, unless they are produced by a nonstandard mechanism (resonant oscillations, coupling with the inflation) or get diluted by a large entropy release. PMID:17026219

  12. Can Sterile Neutrinos Be Ruled Out as Warm Dark Matter Candidates?

    SciTech Connect

    Viel, Matteo; Lesgourgues, Julien; Haehnelt, Martin G.; Matarrese, Sabino; Riotto, Antonio

    2006-08-18

    We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey Lyman-{alpha} flux power spectrum at 2.2neutrinos and m{sub WDM}(greater-or-similar sign)2 keV (2{sigma}) for early decoupled thermal relics. If we combine this bound with the constraint derived from x-ray flux observations of the Coma cluster, we find that the allowed sterile neutrino mass is {approx}10 keV (in the standard production scenario). Adding constraints based on x-ray fluxes from the Andromeda galaxy, we find that dark matter particles cannot be sterile neutrinos, unless they are produced by a nonstandard mechanism (resonant oscillations, coupling with the inflaton) or get diluted by a large entropy release.

  13. Plots and Figures from the Main Injector Neutrino Oscillation Search (MINOS) at Fermilab

    DOE Data Explorer

    MINOS, or Main Injector Neutrino Oscillation Search, is an experiment at Fermilab designed to study the phenomena known as neutrino oscillations. It uses a beam of neutrino particles produced by the NuMI beamline facility - Neutrinos at the Main Injector. The beam of neutrinos is sent through the two MINOS detectors, one at Fermilab and one in the Soudan Mine in northern Minnesota. The Minos for Scientists page provides a link to the data plots that are available to the public and also provides explanations for some of the recent results of the experiment. Another links leads to a long listing of MINOS publications in refereed journals. Photo galleries are found by checking the links on the left menu.

  14. A search for muon neutrino to electron neutrino oscillations at delta(m^2)>0.1 eV^2

    SciTech Connect

    Patterson, Ryan Benton; /Princeton U.

    2007-11-01

    The evidence is compelling that neutrinos undergo flavor change as they propagate. In recent years, experiments have observed this phenomenon of neutrino oscillations using disparate neutrino sources: the sun, fission reactors, accelerators, and secondary cosmic rays. The standard model of particle physics needs only simple extensions - neutrino masses and mixing - to accommodate all neutrino oscillation results to date, save one. The 3.8{sigma}-significant {bar {nu}}{sub e} excess reported by the LSND collaboration is consistent with {bar {nu}}{sub {mu}} {yields}{bar {nu}}{sub e} oscillations with a mass-squared splitting of {Delta}m{sup 2} {approx} 1 eV{sup 2}. This signal, which has not been independently verified, is inconsistent with other oscillation evidence unless more daring standard model extensions (e.g. sterile neutrinos) are considered.

  15. Neutrino-oscillation experiments at Brookhaven National Laboratory

    SciTech Connect

    Ahrens, L.A.; Aronson, S.A.; Connolly, P.L.; Gibbard, B.G.; Maeda, Y.; Murtagh, M.J.; Murtagh, S.J.; Terada, S.; Callas, J.; Cutts, D.

    1983-01-01

    Two groups have submitted major proposals for neutrino oscillation searches at BNL. Both are two detector experiments with a close detector at approx. = 100m and a far detector at approx. = 900m. While the details of the experiments are quite different, both groups expect to obtain nu/sub ..mu../ disappearance limits of delta m/sup 2/sin2 theta approx. = 0.1 - 0.2 for small mass difference and sin/sup 2/2 theta at the few percent level for the most sensitive delta m/sup 2/(approx. = 25eV/sup 2/). Since both detectors are designed to identify electrons as well as muons they expect to obtain significant limits on nu/sub e/ appearance (nu/sub ..mu../ ..-->.. nu/sub e/). Each has received approval for a single detector (Phase I) experiment with the two detector phase (Phase II) still pending. The present status of the single detector experiments is detailed. (WHK)

  16. Solar neutrinos: Near-far asymmetry and just-so oscillations

    SciTech Connect

    Faied, B.; Fogli, G.L.; Montanino, D.

    1997-02-01

    We propose to study possible signals of just-so oscillations in new-generation solar neutrino experiments by separating the events detected when the Earth is nearest to the Sun (perihelion {plus_minus} 3 months) from those detected when the Earth is farthest from the Sun (aphelion {plus_minus} 3 months). We introduce a solar-model-independent near-far asymmetry, which is nonzero if just-so oscillations occur. We apply our calculations to the kinetic energy spectra of electrons induced by {sup 8}B solar neutrino interactions in the SuperKamiokande and Sudbury Neutrino Observatory experiments. We show that the sensitivity to the neutrino oscillation parameters can be increased by probing the near-far asymmetry in selected parts of the electron energy spectra. {copyright} {ital 1997} {ital The American Physical Society}

  17. Cold dark matter from heavy right-handed neutrino mixing

    SciTech Connect

    Anisimov, Alexey; Di Bari, Pasquale

    2009-10-01

    We show that, within the seesaw mechanism, an almost decoupled right-handed (RH) neutrino species N{sub DM} with mass M{sub DM} > or approx. 100 GeV can play the role of dark matter (DM). The N{sub DM}'s can be produced from nonadiabatic conversions of thermalized (source) RH neutrinos with mass M{sub S} lower than M{sub DM}. This is possible if a nonrenormalizable operator is added to the minimal type I seesaw Lagrangian. The observed DM abundance can be reproduced for M{sub DM}{delta}{sup 1/4}{approx}10{sup -13}{lambda}{sub eff}{xi}, where {lambda}{sub eff} is a very high energy new physics scale, {delta}{identical_to}(M{sub DM}-M{sub S})/M{sub DM}, and {xi} < or approx. 1 is a parameter determined by the RH neutrino couplings.

  18. Role of dense matter in collective supernova neutrino transformations

    SciTech Connect

    Esteban-Pretel, A.; Pastor, S.; Mirizzi, A.; Tomas, R.; Raffelt, G. G.; Serpico, P. D.; Sigl, G.

    2008-10-15

    For neutrinos streaming from a supernova core, dense matter suppresses self-induced flavor transformations if the electron density n{sub e} significantly exceeds the neutrino density n{sub {nu}} in the conversion region. If n{sub e} is comparable to n{sub {nu}}, one finds multiangle decoherence, whereas the standard self-induced transformation behavior requires that in the transformation region n{sub {nu}} is safely above n{sub e}. This condition need not be satisfied in the early phase after the supernova core bounce. Our new multiangle effect is a subtle consequence of neutrinos traveling on different trajectories when streaming from a source that is not pointlike.

  19. Sterile neutrino dark matter from freeze-in

    NASA Astrophysics Data System (ADS)

    Shakya, Bibhushan

    2016-01-01

    A sterile neutrino is a well-motivated and widely studied dark matter (DM) candidate. The most straightforward realization of sterile neutrino DM, through the Dodelson-Widrow (DW) mechanism, is now ruled out by a combination of X-ray and Lyman-α measurements. An alternative production mechanism that is becoming increasingly popular in the literature is the freeze-in mechanism, involving frameworks where a feeble coupling to a particle — usually a scalar beyond the Standard Model — in the thermal bath results in a gradual accumulation of the sterile neutrino DM abundance. This paper reviews the various motivations for realizing such frameworks in the literature, their common characteristic features and phenomenological signatures.

  20. The effect of collective flavor oscillations on the diffuse supernova neutrino background

    SciTech Connect

    Chakraborty, Sovan; Kar, Kamales; Dasgupta, Basudeb E-mail: sandhya@hri.res.in E-mail: basudeb@theory.tifr.res.in

    2008-09-15

    Collective flavor oscillations driven by neutrino-neutrino interactions inside core-collapse supernovae have now been shown to drastically alter the resultant neutrino fluxes. This would in turn significantly affect the diffuse supernova neutrino background (DSNB), created by all core-collapse supernovae that have exploded in the past. In view of these collective effects, we re-analyze the potential for detecting the DSNB in currently running and planned large scale detectors meant for detecting both {nu}-bar{sub e} and {nu}{sub e}. We find that the event rate can be different from previous estimates by up to 50%, depending on the value of {theta}{sub 13}. The next generation detectors should be able to observe DSNB fluxes. Under certain conducive conditions, one could learn about neutrino parameters. For instance, it might be possible to determine the neutrino mass hierarchy, even if {theta}{sub 13}{yields}0.

  1. Neutrino experiments: Hierarchy, CP, CPT

    NASA Astrophysics Data System (ADS)

    Gupta, Manmohan; Randhawa, Monika; Singh, Mandip

    2016-07-01

    We present an overview of our recent investigations regarding the prospects of ongoing neutrino experiments as well as future experiments in determining few of the most important unknowns in the field of neutrino physics, specifically the neutrino mass ordering and leptonic CP-violation phase. The effect of matter oscillations on the neutrino oscillation probabilities has been exploited in resolving the degeneracy between the neutrino mass ordering and the CP violation phase in the leptonic sector. Further, we estimate the extent of extrinsic CP and CPT violation in the experiments with superbeams as well as neutrino factories.

  2. Neutrinos from Kaluza-Klein dark matter in the Sun

    SciTech Connect

    Blennow, Mattias; Melbéus, Henrik; Ohlsson, Tommy E-mail: melbeus@kth.se

    2010-01-01

    We investigate indirect neutrino signals from annihilations of Kaluza-Klein dark matter in the Sun. Especially, we examine a five- as well as a six-dimensional model, and allow for the possibility that boundary localized terms could affect the spectrum to give different lightest Kaluza-Klein particles, which could constitute the dark matter. The dark matter candidates that are interesting for the purpose of indirect detection of neutrinos are the first Kaluza-Klein mode of the gauge boson and the neutral component of the gauge bosons. Using the DarkSUSY and WimpSim packages, we calculate muon fluxes at an Earth-based neutrino telescope, such as IceCube. For the five-dimensional model, the results that we obtained agree reasonably well with the results that have previously been presented in the literature, whereas for the six-dimensional model, we find that, at tree-level, the results are the same as for the five-dimensional model. Finally, if the first Kaluza-Klein mode of the gauge boson constitutes the dark matter, IceCube can constrain the parameter space. However, in the case that the neutral component of the gauge bosons is the LKP, the signal is too weak to be observed.

  3. Neutrino refraction by the cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Díaz, J. S.; Klinkhamer, F. R.

    2016-03-01

    We have determined the dispersion relation of a neutrino test particle propagating in the cosmic neutrino background. Describing the relic neutrinos and antineutrinos from the hot big bang as a dense medium, a matter potential or refractive index is obtained. The vacuum neutrino mixing angles are unchanged, but the energy of each mass state is modified. Using a matrix in the space of neutrino species, the induced potential is decomposed into a part which produces signatures in beta-decay experiments and another part which modifies neutrino oscillations. The low temperature of the relic neutrinos makes a direct detection extremely challenging. From a different point of view, the identified refractive effects of the cosmic neutrino background constitute an ultralow background for future experimental studies of nonvanishing Lorentz violation in the neutrino sector.

  4. Astrophysical constraints on resonantly produced sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Schneider, Aurel

    2016-04-01

    Resonantly produced sterile neutrinos are considered an attractive dark matter (DM) candidate only requiring a minimal, well motivated extension to the standard model of particle physics. With a particle mass restricted to the keV range, sterile neutrinos are furthermore a prime candidate for warm DM, characterised by suppressed matter perturbations at the smallest observable scales. In this paper we take a critical look at the validity of the resonant scenario in the context of constraints from structure formation. We compare predicted and observed number of Milky-Way satellites and we introduce a new method to generalise existing Lyman-α limits based on thermal relic warm DM to the case of resonant sterile neutrino DM . The tightest limits come from the Lyman-α analysis, excluding the entire parameter space (at 2-σ confidence level) still allowed by X-ray observations. Constraints from Milky-Way satellite counts are less stringent, leaving room for resonant sterile neutrino DM most notably around the suggested line signal at 7.1 keV.

  5. Compatibility of high-{delta}m{sup 2} {nu}{sub e} and {nu}{sub e} neutrino oscillation searches

    SciTech Connect

    Aguilar-Arevalo, A. A.; Bugel, L.; Coney, L.; Conrad, J. M.; Djurcic, Z.; Karagiorgi, G.; Mahn, K. B. M.; Monroe, J.; Nguyen, V. T.; Schmitz, D.; Shaevitz, M. H.; Sorel, M.; Anderson, C. E.; Curioni, A.; Fleming, B. T.; Linden, S. K.; Soderberg, M.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.

    2008-07-01

    This article presents the compatibility of experimental data from neutrino oscillation experiments with a high-{delta}m{sup 2} two-neutrino oscillation hypothesis. Data is provided by the Bugey, Karlsruhe Rutherford Medium Energy Neutrino Experiment 2 (KARMEN2), Los Alamos Liquid Scintillator Neutrino Detector (LSND), and MiniBooNE experiments. The LSND, KARMEN2, and MiniBooNE results are 25.36% compatible within a two-neutrino oscillation hypothesis. However, the point of maximal compatibility is found in a region that is excluded by the Bugey data. A joint analysis of all four experiments, performed in the sin{sup 2}2{theta} vs {delta}m{sup 2} region common to all data, finds a maximal compatibility of 3.94%. This result does not account for additions to the neutrino oscillation model from sources such as CP violation or sterile neutrinos.

  6. SIMULATION OF A WIDE-BAND LOW-ENERGY NEUTRINO BEAM FOR VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS.

    SciTech Connect

    BISHAI, M.; HEIM, J.; LEWIS, C.; MARINO, A.D.; VIREN, B.; YUMICEVA, F.

    2006-08-01

    We present simulations of a wide-band low-energy neutrino beam for a future very long baseline neutrino oscillation (VLBNO) program using the proton beam from the Main Injector (MI) proton accelerator at Fermi National Accelerator Laboratory (Fermilab). The target and horn designs previously developed for Brookhaven Laboratory's Alternating Gradient Synchrotron (AGS) VLBNO program are used without modifications. The neutrino flux distributions for various MI proton beam energies and new high-intensity neutrino beam-line designs possible at Fermilab are presented. The beam-line siting and design parameters are chosen to match the requirements of an on-axis beam from Fermilab to one of the two possible sites for the future Deep Underground Science and Engineering Laboratory (DUSEL). A preliminary estimate of the observable event rates and spectra at a detector located in DUSEL for different beam configurations has been performed. Our preliminary conclusions are that a 40-60 GeV 0.5 to 1 MW beam from the Fermilab Main Injector to a DUSEL site has the potential to reach the desired intensity for the next generation of neutrino oscillation experiments. Recent studies indicate that the Fermilab MI can reach a beam power of 0.5 MW at 60 GeV with incremental upgrades to the existing accelerator complex.

  7. Precision measurement of solar neutrino oscillation parameters by a long-baseline reactor neutrino experiment in Europe

    NASA Astrophysics Data System (ADS)

    Petcov, S. T.; Schwetz, T.

    2006-11-01

    We consider the determination of the solar neutrino oscillation parameters Δm212 and θ12 by studying oscillations of reactor anti-neutrinos emitted by nuclear power plants (located mainly in France) with a detector installed in the Frejus underground laboratory. The performances of a water Čerenkov detector of 147 kt fiducial mass doped with 0.1% of gadolinium (MEMPHYS-Gd) and of a 50 kt scale liquid scintillator detector (LENA) are compared. In both cases 3σ uncertainties below 3% on Δm212 and of about 20% on sin2θ12 can be obtained after one year of data taking. The gadolinium doped Super-Kamiokande detector (SK-Gd) in Japan can reach a similar precision if the SK/MEMPHYS fiducial mass ratio of 1 to 7 is compensated by a longer SK-Gd data taking time. Several years of reactor neutrino data collected by MEMPHYS-Gd or LENA would allow a determination of Δm212 and sin2θ12 with uncertainties of approximately 1% and 10% at 3σ, respectively. These accuracies are comparable to those that can be reached in the measurement of the atmospheric neutrino oscillation parameters Δm312 and sin2θ23 in long-baseline superbeam experiments.

  8. Topical Collaboration "Neutrinos and Nucleosynthesis in Hot and Dense Matter"

    SciTech Connect

    Allahverdi, Rouzbeh

    2015-09-18

    This is the final technical report describing contributions from the University of New Mexico to Topical Collaboration on "Neutrinos and Nucleosynthesis in Hot and Dense Matter" in the period June 2010 through May 2015. During the funding period, the University of New Mexico successfully hired Huaiyu Duan as a new faculty member with the support from DOE, who has contributed to the Topical Collaboration through his research and collaborations.

  9. Peccei-Quinn symmetry, dark matter, and neutrino mass

    SciTech Connect

    Ma, Ernest

    2014-06-24

    It is pointed out that a residual Z{sub 2} symmetry of the usual anomalous Peccei-Quinn U(1){sub PQ} symmetry (which solves the strong CP problem) may be used for an absolutely stable heavy dark-matter particle in addition to the long-lived axion. The same Z{sub 2} symmetry may also be used to generate radiative neutrino mass.

  10. Shifts of neutrino oscillation parameters in reactor antineutrino experiments with non-standard interactions

    NASA Astrophysics Data System (ADS)

    Li, Yu-Feng; Zhou, Ye-Ling

    2014-11-01

    We discuss reactor antineutrino oscillations with non-standard interactions (NSIs) at the neutrino production and detection processes. The neutrino oscillation probability is calculated with a parametrization of the NSI parameters by splitting them into the averages and differences of the production and detection processes respectively. The average parts induce constant shifts of the neutrino mixing angles from their true values, and the difference parts can generate the energy (and baseline) dependent corrections to the initial mass-squared differences. We stress that only the shifts of mass-squared differences are measurable in reactor antineutrino experiments. Taking Jiangmen Underground Neutrino Observatory (JUNO) as an example, we analyze how NSIs influence the standard neutrino measurements and to what extent we can constrain the NSI parameters. Long baseline reactor antineutrino experiments, such as KamLAND [10,11]. The aim of these experiments is to observe the slow oscillation with Δ21 and measure the corresponding oscillation parameters Δm212 and θ12. Short baseline reactor antineutrino experiments, such as Daya Bay [1-3], Double CHOOZ [4], RENO [5]. They are designed to observe the fast oscillation with Δ31 and Δ32 (or equivalently, Δee[3]) and measure the corresponding oscillation parameters Δmee2, θ13. Medium baseline reactor antineutrino experiments. They stand for the next generation experiments of reactor antineutrinos, with typical representatives of Jiangmen Underground Neutrino Observatory (JUNO) [12] and RENO-50 [13]. They can determine the neutrino mass ordering (m1oscillations and become a bridge between short baseline and long baseline reactor antineutrino experiments. High-dimensional operators originating from new physics can contribute to the neutrino oscillation in the form of non-standard interactions (NSIs) [14

  11. Charged-current weak interaction processes in hot and dense matter and its impact on the spectra of neutrinos emitted from protoneutron star cooling.

    PubMed

    Martínez-Pinedo, G; Fischer, T; Lohs, A; Huther, L

    2012-12-21

    We perform three-flavor Boltzmann neutrino transport radiation hydrodynamics simulations covering a period of 3 s after the formation of a protoneutron star in a core-collapse supernova explosion. Our results show that a treatment of charged-current neutrino interactions in hot and dense matter as suggested by Reddy et al. [Phys. Rev. D 58, 013009 (1998)] has a strong impact on the luminosities and spectra of the emitted neutrinos. When compared with simulations that neglect mean-field effects on the neutrino opacities, we find that the luminosities of all neutrino flavors are reduced while the spectral differences between electron neutrinos and antineutrinos are increased. Their magnitude depends on the equation of state and in particular on the symmetry energy at subnuclear densities. These modifications reduce the proton-to-nucleon ratio of the outflow, increasing slightly their entropy. They are expected to have a substantial impact on nucleosynthesis in neutrino-driven winds, even though they do not result in conditions that favor an r process. Contrary to previous findings, our results show that the spectra of electron neutrinos remain substantially different from those of other (anti)neutrino flavors during the entire deleptonization phase of the protoneutron star. The obtained luminosity and spectral changes are also expected to have important consequences for neutrino flavor oscillations and neutrino detection on Earth. PMID:23368446

  12. Measurement of neutrino oscillation with KamLAND: evidence of spectral distortion.

    PubMed

    Araki, T; Eguchi, K; Enomoto, S; Furuno, K; Ichimura, K; Ikeda, H; Inoue, K; Ishihara, K; Iwamoto, T; Kawashima, T; Kishimoto, Y; Koga, M; Koseki, Y; Maeda, T; Mitsui, T; Motoki, M; Nakajima, K; Ogawa, H; Owada, K; Ricol, J-S; Shimizu, I; Shirai, J; Suekane, F; Suzuki, A; Tada, K; Tajima, O; Tamae, K; Tsuda, Y; Watanabe, H; Busenitz, J; Classen, T; Djurcic, Z; Keefer, G; McKinny, K; Mei, D-M; Piepke, A; Yakushev, E; Berger, B E; Chan, Y D; Decowski, M P; Dwyer, D A; Freedman, S J; Fu, Y; Fujikawa, B K; Goldman, J; Gray, F; Heeger, K M; Lesko, K T; Luk, K-B; Murayama, H; Poon, A W P; Steiner, H M; Winslow, L A; Horton-Smith, G A; Mauger, C; McKeown, R D; Vogel, P; Lane, C E; Miletic, T; Gorham, P W; Guillian, G; Learned, J G; Maricic, J; Matsuno, S; Pakvasa, S; Dazeley, S; Hatakeyama, S; Rojas, A; Svoboda, R; Dieterle, B D; Detwiler, J; Gratta, G; Ishii, K; Tolich, N; Uchida, Y; Batygov, M; Bugg, W; Efremenko, Y; Kamyshkov, Y; Kozlov, A; Nakamura, Y; Gould, C R; Karwowski, H J; Markoff, D M; Messimore, J A; Nakamura, K; Rohm, R M; Tornow, W; Wendell, R; Young, A R; Chen, M-J; Wang, Y-F; Piquemal, F

    2005-03-01

    We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date. PMID:15783875

  13. Bruno Pontecorvo: From slow neutrons to oscillating neutrinos

    NASA Astrophysics Data System (ADS)

    Bonolis, Luisa

    2005-06-01

    Bruno Pontecorvo's work in neutrino physics is examined and due emphasis is given to the audacity of his ideas both theoretically and experimentally. The account ends with the first solar neutrinos detected by Raymond Davis in 1967 using the radiochemical method developed by Pontecorvo in 1945.

  14. Recent Results in Solar Neutrinos

    NASA Astrophysics Data System (ADS)

    Saldanha, Richard

    2011-10-01

    Solar neutrinos are an invaluable tool for studying neutrino oscillations in matter as well as probing the nuclear reactions that fuel the Sun. In this talk I will give an overview of solar neutrinos and discuss the latest results in the field. I will highlight the recent precision measurement of the ^7Be solar neutrino interaction rate with the Borexino solar neutrino detector and present the status of the analysis of pep and CNO neutrinos. I will also briefly describe future experiments and their potential to detect low energy solar neutrinos.

  15. Sterile neutrinos and indirect dark matter searches in IceCube

    SciTech Connect

    Argüelles, Carlos A.; Kopp, Joachim E-mail: jkopp@fnal.gov

    2012-07-01

    If light sterile neutrinos exist and mix with the active neutrino flavors, this mixing will affect the propagation of high-energy neutrinos from dark matter annihilation in the Sun. In particular, new Mikheyev-Smirnov-Wolfenstein resonances can occur, leading to almost complete conversion of some active neutrino flavors into sterile states. We demonstrate how this can weaken IceCube limits on neutrino capture and annihilation in the Sun and how potential future conflicts between IceCube constraints and direct detection or collider data might be resolved by invoking sterile neutrinos. We also point out that, if the dark matter-nucleon scattering cross section and the allowed annihilation channels are precisely measured in direct detection and collider experiments in the future, IceCube can be used to constrain sterile neutrino models using neutrinos from the dark matter annihilation.

  16. Active-sterile neutrino oscillations in the early Universe with full collision terms

    SciTech Connect

    Hannestad, Steen; Hansen, Rasmus Sloth; Tram, Thomas; Wong, Yvonne Y.Y.

    2015-08-11

    Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.

  17. Measurement of neutrino oscillations with the MINOS detectors in the NuMI beam.

    PubMed

    Adamson, P; Andreopoulos, C; Arms, K E; Armstrong, R; Auty, D J; Ayres, D S; Baller, B; Barnes, P D; Barr, G; Barrett, W L; Becker, B R; Belias, A; Bernstein, R H; Bhattacharya, D; Bishai, M; Blake, A; Bock, G J; Boehm, J; Boehnlein, D J; Bogert, D; Bower, C; Buckley-Geer, E; Cavanaugh, S; Chapman, J D; Cherdack, D; Childress, S; Choudhary, B C; Cobb, J H; Coleman, S J; Culling, A J; de Jong, J K; Dierckxsens, M; Diwan, M V; Dorman, M; Dytman, S A; Escobar, C O; Evans, J J; Harris, E Falk; Feldman, G J; Frohne, M V; Gallagher, H R; Godley, A; Goodman, M C; Gouffon, P; Gran, R; Grashorn, E W; Grossman, N; Grzelak, K; Habig, A; Harris, D; Harris, P G; Hartnell, J; Hatcher, R; Heller, K; Himmel, A; Holin, A; Hylen, J; Irwin, G M; Ishitsuka, M; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Kim, J J; Kim, M S; Koizumi, G; Kopp, S; Kordosky, M; Koskinen, D J; Kotelnikov, S K; Kreymer, A; Kumaratunga, S; Lang, K; Ling, J; Litchfield, P J; Litchfield, R P; Loiacono, L; Lucas, P; Ma, J; Mann, W A; Marchionni, A; Marshak, M L; Marshall, J S; Mayer, N; McGowan, A M; Meier, J R; Merzon, G I; Messier, M D; Metelko, C J; Michael, D G; Miller, J L; Miller, W H; Mishra, S R; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Murgia, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nicholls, T C; Ochoa-Ricoux, J P; Oliver, W P; Ospanov, R; Paley, J; Paolone, V; Para, A; Patzak, T; Pavlović, Z; Pawloski, G; Pearce, G F; Peck, C W; Peterson, E A; Petyt, D A; Pittam, R; Plunkett, R K; Rahaman, A; Rameika, R A; Raufer, T M; Rebel, B; Reichenbacher, J; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Ruddick, K; Ryabov, V A; Sanchez, M C; Saoulidou, N; Schneps, J; Schreiner, P; Seun, S-M; Shanahan, P; Smart, W; Smith, C; Sousa, A; Speakman, B; Stamoulis, P; Strait, M; Symes, P; Tagg, N; Talaga, R L; Tavera, M A; Thomas, J; Thompson, J; Thomson, M A; Thron, J L; Tinti, G; Trostin, I; Tsarev, V A; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Ward, C P; Ward, D R; Watabe, M; Weber, A; Webb, R C; Wehmann, A; West, N; White, C; Wojcicki, S G; Wright, D M; Yang, T; Zois, M; Zhang, K; Zwaska, R

    2008-09-26

    This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively. PMID:18851439

  18. Measurement of Neutrino Oscillations with the MINOS Detectors in the NuMI Beam

    SciTech Connect

    Adamson, P.; Baller, B.; Bernstein, R. H.; Bock, G. J.; Boehnlein, D. J.; Bogert, D.; Buckley-Geer, E.; Childress, S.; Choudhary, B. C.; Grossman, N.; Harris, D.; Hatcher, R.; Hylen, J.; James, C.; Jensen, D.; Koizumi, G.; Kreymer, A.; Lucas, P.; Marchionni, A.; Moore, C. D.

    2008-09-26

    This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |{delta}m{sup 2}|=(2.43{+-}0.13)x10{sup -3} eV{sup 2} (68% C.L.) and mixing angle sin{sup 2}(2{theta})>0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively.

  19. Active-sterile neutrino oscillations in the early Universe with full collision terms

    NASA Astrophysics Data System (ADS)

    Hannestad, Steen; Sloth Hansen, Rasmus; Tram, Thomas; Wong, Yvonne Y. Y.

    2015-08-01

    Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.

  20. Revising the solution of the neutrino oscillation parameter degeneracies at neutrino factories

    SciTech Connect

    Gago, A. M.; Jones Perez, J.

    2007-02-01

    In the context of neutrino factories, we review the solution of the degeneracies in the neutrino oscillation parameters. In particular, we have set limits to sin{sup 2}2{theta}{sub 13} in order to accomplish the unambiguous determination of {theta}{sub 23} and {delta}. We have performed two different analysis. In the first, at a baseline of 3000 km, we simulate a measurement of the channels {nu}{sub e}{yields}{nu}{sub {mu}}, {nu}{sub e}{yields}{nu}{sub {tau}}, and {nu}{sub {mu}}{yields}{nu}{sub {mu}}, combined with their respective conjugate ones, with a muon energy of 50 GeV and a running time of five years. In the second, we merge the simulated data obtained at L=3000 km with the measurement of {nu}{sub e}{yields}{nu}{sub {mu}} channel at 7250 km, the so-called 'magic baseline.' In both cases, we have studied the impact of varying the {nu}{sub {tau}} detector efficiency-mass product ({epsilon}{sub {nu}{tau}xM{tau}}), at 3000 km, keeping unchanged the {nu}{sub {mu}} detector mass and its efficiency. At L=3000 km, we found the existence of degenerate zones, that correspond to values of {theta}{sub 13}, which are equal or almost equal to the true ones. These zones are extremely difficult to discard, even when we increase the number of events. However, in the second scenario, this difficulty is overcome, demonstrating the relevance of the 'magic baseline'. From this scenario, the best limits of sin{sup 2}2{theta}{sub 13}, reached at 3{sigma}, for sin{sup 2}2{theta}{sub 23}=0.95, 0.975, and 0.99 are: 0.008, 0.015, and 0.045, respectively, obtained at {delta}=0, and considering ({epsilon}{sub {nu}{tau}xM{tau}}){approx_equal}125, which is 5 times the initial efficiency-mass combination.

  1. Collective flavor oscillations of supernova neutrinos and r-process nucleosynthesis

    SciTech Connect

    Chakraborty, Sovan; Kar, Kamales; Goswami, Srubabati E-mail: sandhya@hri.res.in E-mail: kamales.kar@saha.ac.in

    2010-06-01

    Neutrino-neutrino interactions inside core-collapse supernovae may give rise to collective flavor oscillations resulting in swap between flavors. These oscillations depend on the initial energy spectra, and relative fluxes or relative luminosities of the neutrinos. It has been observed that departure from energy equipartition among different flavors can give rise to one or more sharp spectral swap over energy, termed as splits. We study the occurrence of splits in the neutrino and antineutrino spectra, varying the initial relative fluxes for different models of initial energy spectrum, in both normal and inverted hierarchy. These initial relative flux variations give rise to several possible split patterns whereas variation over different models of energy spectra give similar results. We explore the effect of these spectral splits on the electron fraction, Y{sub e}, that governs r-process nucleosynthesis inside supernovae. Since spectral splits modify the electron neutrino and antineutrino spectra in the region where r-process is postulated to happen, and since the pattern of spectral splits depends on the initial conditions of the spectra and the neutrino mass hierarchy, we show that the condition Y{sub e} < 0.5 required for successful r-process nucleosynthesis will lead to constraints on the initial spectral conditions, for a given neutrino mass hierarchy.

  2. Hidden MeV-scale dark matter in neutrino detectors

    SciTech Connect

    Kile, Jennifer; Soni, Amarjit

    2009-12-01

    The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction fp{yields}e{sup +}n, where f is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the f lifetime and its decays which produce visible {gamma} rays or electrons. We find one operator which would allow fp{yields}e{sup +}n at interesting rates in neutrino detectors, as long as m{sub f} < or approx. m{sub {pi}}. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross section for fp{yields}e{sup +}n in neutrino detectors implied by this operator, and find that Super-Kamiokande can probe the new physics scale {lambda} for this interaction up to O(100 TeV)

  3. Method of wave equations exact solutions in studies of neutrinos and electrons interaction in dense matter

    NASA Astrophysics Data System (ADS)

    Studenikin, A. I.

    2008-04-01

    We present quite a powerful method in investigations of different phenomena that can appear when neutrinos and electrons propagate in background matter. This method implies use of exact solutions of modified Dirac equations that contain the correspondent effective potentials accounting for the matter influence on particles. For several particular cases the exact solutions of modified Dirac and Dirac-Pauli equations for a neutrino and an electron in the background environment of different composition are obtained (the case of magnetized matter is also considered). Neutrino reflection, trapping, neutrino pair creation and annihilation in matter and neutrino energy quantization in a rotating medium are discussed. The neutrino Green functions in matter are also derived. The two recently proposed mechanisms of electromagnetic radiation by a neutrino and an electron in matter (the spin light of neutrino and electron, SLν and SLe) are considered. A possibility to introduce an effective 'matter-induced Lorentz force' acting on a neutrino and an electron is discussed. A new mechanism of electromagnetic radiation that can be emitted by an electron moving in the neutrino background with nonzero gradient of density is predicted.

  4. Magnetically induced neutrino oscillations and neutrino refractive effects in the early universe

    NASA Technical Reports Server (NTRS)

    Fukugita, Masataka; Noetzold, Dirk; Raffelt, Georg; Silk, Joseph

    1988-01-01

    The interrelation between hypothetical neutrino magnetic dipole moments (MDMs) and primeval magnetic fields is discussed. The parameter range over which these possibilities are mutually exclusive is determined, taking into account for the first time neutrino refractive effects in the early universe. It is shown that an independent determination of either the neutrino MDMs or the primeval magnetic field strength would set powerful bounds on the other quantity.

  5. Observing a light dark matter beam with neutrino experiments

    NASA Astrophysics Data System (ADS)

    Deniverville, Patrick; Pospelov, Maxim; Ritz, Adam

    2011-10-01

    We consider the sensitivity of fixed-target neutrino experiments at the luminosity frontier to light stable states, such as those present in models of MeV-scale dark matter. To ensure the correct thermal relic abundance, such states must annihilate via light mediators, which in turn provide an access portal for direct production in colliders or fixed targets. Indeed, this framework endows the neutrino beams produced at fixed-target facilities with a companion “dark matter beam,” which may be detected via an excess of elastic scattering events off electrons or nuclei in the (near-)detector. We study the high-luminosity proton fixed-target experiments at LSND and MiniBooNE, and determine that the ensuing sensitivity to light dark matter generally surpasses that of other direct probes. For scenarios with a kinetically-mixed U(1)' vector mediator of mass mV, we find that a large volume of parameter space is excluded for mDM˜1-5MeV, covering vector masses 2mDM≲mV≲mη and a range of kinetic mixing parameters reaching as low as κ˜10-5. The corresponding MeV-scale dark matter scenarios motivated by an explanation of the galactic 511 keV line are thus strongly constrained.

  6. Using Quasi-Elastic Events to Measure Neutrino Oscillations with MINOS Detectors in the NuMI Neutrino Beam

    SciTech Connect

    Watabe, Masaki

    2010-05-01

    MINOS (Main Injector Neutrino Oscillation Search) experiment has been designed to search for a change in the avor composition of a beam of muon neutrinos as they travel between the Near Detector at Fermi National Accelerator Laboratory and the Far Detector in the Soudan mine in Minnesota, 735 km from the target. The MINOS oscillation analysis is mainly performed with the charged current (CC) events and sensitive to constrain high- Δm2 values. However, the quasi-elastic (QEL) charged current interaction is dominant in the energy region important to access low- m2 values. For further improvement, the QEL oscillation analysis is performed in this dissertation. A data sample based on a total of 2.50 x 1020 POT is used for this analysis. In summary, 55 QEL-like events are observed at the Far detector while 87.06 ± 13.17 (syst:) events are expected with null oscillation hypothesis. These data are consistent with disappearance via oscillation with m2 = 2:10 0.37 (stat:) ± 0.24 (syst:) eV2 and the maximal mixing angle.

  7. FIRST STUDY OF DARK MATTER PROPERTIES WITH DETECTED SOLAR GRAVITY MODES AND NEUTRINOS

    SciTech Connect

    Turck-Chieze, S.; Garcia, R. A.; Ballot, J.; Couvidat, S.; Mathur, S.; Salabert, D.; Silk, J.

    2012-02-10

    We derive new limits on the cold dark matter properties for weakly interacting massive particles (WIMPs), potentially trapped in the solar core by using for the first time the central temperature constrained by boron neutrinos and the central density constrained by the dipolar gravity modes detected with the Global Oscillations at Low Frequency/Solar Helioseismic Observatory instrument. These detections disfavor the presence of non-annihilating WIMPs for masses {<=}10 GeV and spin dependent cross-sections >5 Multiplication-Sign 10{sup -36} cm{sup 2} in the solar core but cannot constrain WIMP annihilation models. We suggest that in the coming years helio- and asteroseismology will provide complementary probes of dark matter.

  8. SOX: search for short baseline neutrino oscillations with Borexino

    NASA Astrophysics Data System (ADS)

    Vivier, M.; Agostini, M.; Altenmüller, K.; Appel, S.; Bellini, G.; Benziger, J.; Berton, N.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; Choi, K.; Cribier, M.; D’Angelo, D.; Davini, S.; Derbin, A.; Di Noto, L.; Drachnev, I.; Durero, M.; Etenko, A.; Farinon, S.; Fischer, V.; Fomenko, K.; Franco, D.; Gabriele, F.; Gaffliot, J.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, T.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonquàres, N.; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kornoukhov, V.; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Lehnert, B.; Link, J.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Maricic, J.; Mention, G.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Scola, L.; Semenov, D.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Veyssiére, C.; Unzhakov, E.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.; Borexino collaboration

    2016-05-01

    The Borexino detector has convincingly shown its outstanding performances in the low energy regime through its accomplishments in the observation and study of the solar and geo neutrinos. It is then an ideal tool to perform a state of the art source-based experiment for testing the longstanding hypothesis of a fourth sterile neutrino with ~ eV2 mass, as suggested by several anomalies accumulated over the past three decades in source, reactor, and accelerator-based experiments. The SOX project aims at successively deploying two intense radioactive sources, made of Cerium (antineutrino) and Chromium (neutrino), respectively, in a dedicated pit located beneath the detector. The existence of such an ~ eV2 sterile neutrino would then show up as an unambiguous spatial and energy distortion in the count rate of neutrinos interacting within the active detector volume. This article reports on the latest developments about the first phase of the SOX experiment, namely CeSOX, and gives a realistic projection of CeSOX sensitivity to light sterile neutrinos in a simple (3+1) model.

  9. Distinguishing neutrino mass hierarchies using dark matter annihilation signals at IceCube

    SciTech Connect

    Allahverdi, Rouzbeh; Dutta, Bhaskar; Ghosh, Dilip Kumar; Knockel, Bradley; Saha, Ipsita

    2015-12-01

    We explore the possibility of distinguishing neutrino mass hierarchies through the neutrino signal from dark matter annihilation at neutrino telescopes. We consider a simple extension of the standard model where the neutrino masses and mixing angles are obtained via the type-II seesaw mechanism as an explicit example. We show that future extensions of IceCube neutrino telescope may detect the neutrino signal from DM annihilation at the Galactic Center and inside the Sun, and differentiate between the normal and inverted mass hierarchies, in this model.

  10. BBN with electron-sterile neutrino oscillations — the finest leptometer

    SciTech Connect

    Kirilova, Daniela

    2012-06-01

    A relic lepton asymmetry orders of magnitude bigger than the baryon one may hide in the relic neutrino background. No direct theoretical or experimental limitations on its magnitude and sign are known. Only indirect cosmological constraints exist ranging from |L| < 0.01 to L < 10. Here we discuss a Big Bang Nucleosynthesis (BBN) model with late electron-sterile neutrino oscillations. The influence of L on neutrino oscillations and on nucleons freezing in the pre-BBN epoch is numerically analyzed in the full range of the oscillation parameters of the model and for |L| ≥ 10{sup −10}. The asymmetry-oscillations interplay is studied in detail and the behavior of L for different oscillation parameters is found. L effect on the primordially produced {sup 4}He is precisely studied. It is shown that this BBN model is a fine leptometer, capable of feeling extremely small relic lepton asymmetry — |L| > 10{sup −8}. The case of oscillations generated asymmetry by late electron-sterile oscillations and its effect on the primordial {sup 4}He is also briefly discussed. The instability region of the asymmetry growth is obtained.

  11. Neutrino masses, leptogenesis, and dark matter in a hybrid seesaw model

    SciTech Connect

    Gu Peihong; Hirsch, M.; Valle, J. W. F.

    2009-02-01

    We suggest a hybrid seesaw model where relatively light right-handed neutrinos give no contribution to neutrino mass matrix due to a special symmetry. This allows their Yukawa couplings to the standard model particles to be relatively strong, so that the standard model Higgs boson can decay dominantly to a left- and a right-handed neutrino, leaving another stable right-handed neutrino as cold dark matter. In our model neutrino masses arise via the type-II seesaw mechanism, the Higgs triplet scalars being also responsible for the generation of the matter-antimatter asymmetry via the leptogenesis mechanism.

  12. Leptogenesis, radiative neutrino masses and inert Higgs triplet dark matter

    NASA Astrophysics Data System (ADS)

    Lu, Wen-Bin; Gu, Pei-Hong

    2016-05-01

    We extend the standard model by three types of inert fields including Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic Higgs doublets. In the presence of a softly broken lepton number and an exactly conserved Z2 discrete symmetry, these inert fields together can mediate a one-loop diagram for a Majorana neutrino mass generation. The heavier inert fields can decay to realize a successful leptogenesis while the lightest inert field can provide a stable dark matter candidate. As an example, we demonstrate the leptogenesis by the inert Higgs doublet decays. We also perform a systematic study on the inert Higgs triplet dark matter scenario where the interference between the gauge and Higgs portal interactions can significantly affect the dark matter properties.

  13. Neutrino Experiments

    SciTech Connect

    McKeown, R. D.

    2010-08-04

    Recent studies of neutrino oscillations have established the existence of finite neutrino masses and mixing between generations of neutrinos. The combined results from studies of atmospheric neutrinos, solar neutrinos, reactor antineutrinos and neutrinos produced at accelerators paint an intriguing picture that clearly requires modification of the standard model of particle physics. These results also provide clear motivation for future neutrino oscillation experiments as well as searches for direct neutrino mass and nuclear double-beta decay. I will discuss the program of new neutrino oscillation experiments aimed at completing our knowledge of the neutrino mixing matrix.

  14. New or ν missing energy: Discriminating dark matter from neutrino interactions at the LHC

    NASA Astrophysics Data System (ADS)

    Franzosi, Diogo Buarque; Frandsen, Mads T.; Shoemaker, Ian M.

    2016-05-01

    Missing energy signals such as monojets are a possible signature of dark matter (DM) at colliders. However, neutrino interactions beyond the Standard Model may also produce missing energy signals. In order to conclude that new "missing particles" are observed, the hypothesis of beyond the Standard Model neutrino interactions must be rejected. In this paper, we first derive new limits on these nonstandard neutrino interactions (NSIs) from LHC monojet data. For heavy NSI mediators, these limits are much stronger than those coming from traditional low-energy ν scattering or ν oscillation experiments for some flavor structures. Monojet data alone can be used to infer the mass of the missing particle from the shape of the missing energy distribution. In particular, 13 TeV LHC data will have sensitivity to DM masses greater than ˜1 TeV . In addition to the monojet channel, NSI can be probed in multilepton searches which we find to yield stronger limits at heavy mediator masses. The sensitivity offered by these multilepton channels provides a method to reject or confirm the DM hypothesis in missing energy searches.

  15. Neutrino and axion hot dark matter bounds after WMAP-7

    SciTech Connect

    Hannestad, Steen; Mirizzi, Alessandro; Raffelt, Georg G.; Wong, Yvonne Y.Y. E-mail: alessandro.mirizzi@desy.de E-mail: yvonne.wong@physik.rwth-aachen.de

    2010-08-01

    We update cosmological hot dark matter constraints on neutrinos and hadronic axions. Our most restrictive limits use 7-year data from the Wilkinson Microwave Anisotropy Probe for the cosmic microwave background anisotropies, the halo power spectrum (HPS) from the 7th data release of the Sloan Digital Sky Survey, and the Hubble constant from Hubble Space Telescope observations. We find 95% CL upper limits of Σm{sub ν} < 0.44 eV (no axions), m{sub a} < 0.91 eV (assuming Σm{sub ν} = 0), and Σm{sub ν} < 0.41 eV and m{sub a} < 0.72 eV for two hot dark matter components after marginalising over the respective other mass. CMB data alone yield Σm{sub ν} < 1.19 eV (no axions), while for axions the HPS is crucial for deriving m{sub a} constraints. This difference can be traced to the fact that for a given hot dark matter fraction axions are much more massive than neutrinos.

  16. First Detection of the Acoustic Oscillation Phase Shift Expected from the Cosmic Neutrino Background.

    PubMed

    Follin, Brent; Knox, Lloyd; Millea, Marius; Pan, Zhen

    2015-08-28

    The unimpeded relativistic propagation of cosmological neutrinos prior to recombination of the baryon-photon plasma alters gravitational potentials and therefore the details of the time-dependent gravitational driving of acoustic oscillations. We report here a first detection of the resulting shifts in the temporal phase of the oscillations, which we infer from their signature in the cosmic microwave background temperature power spectrum. PMID:26371637

  17. Double Chooz and the search for short range anti-neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Hartmann, Francis X.

    2009-06-01

    The Double Chooz Experiment seeks to search for short range antineutrino oscillations from the nuclear reactors at the Chooz Nuclear Power Station operated by Electricite de France in Northeastern France. The measurements are of interest to constraining the value for θ13 in current neutrino oscillation models. New scintillator types based on beta-diketone and pH stabilized carboxylic acid chemistry are described. New results from the study of these scintillators in the context of the detector design are reported.

  18. Status and neutrino oscillation physics potential of the Hyper-Kamiokande Project in Japan

    NASA Astrophysics Data System (ADS)

    De Rosa, Gianfranca; Hyper-Kamiokande Protocollaboration

    2016-05-01

    Hyper-Kamiokande (Hyper-K), a proposed one-megaton water Cherenkov detector to be built in Japan, is the logical continuation of the highly successful program of neutrino (astro) physics and proton decay using the water Cherenkov technique. In its baseline design, the Hyper-K detector consists of two cylindrical tanks lying side-by-side, the outer dimensions of each tank being 48m × 54m × 250m. The inner detector region will be instrumented with 99,000 20-inch photo-sensors. An international proto-collaboration has been intensively working on the R&D of key components such as optimization of cavern, tank construction, development of high performance photo-sensors, design of new near detectors and improvements to the J-PARC neutrino beam. Hyper-K will study the CP asymmetry in neutrino oscillations using the neutrino and anti-neutrino beams produced at J-PARC. With an exposure of 7.5 MW × 107 seconds, CP violating parameter delta can be measured to better than 19 degrees at all values of delta, and CP violation can be detected with more than 3 sigma significance for 76% of the values. An overview of the status of project and the studies of the sensitivity of this detector to physics quantities governing neutrino oscillation is presented.

  19. Nearly degenerate heavy sterile neutrinos in cascade decay: Mixing and oscillations

    NASA Astrophysics Data System (ADS)

    Boyanovsky, Daniel

    2014-11-01

    Some extensions beyond the Standard Model propose the existence of nearly degenerate heavy sterile neutrinos. If kinematically allowed these can be resonantly produced and decay in a cascade to common final states. The common decay channels lead to mixing of the heavy sterile neutrino states and interference effects. We implement nonperturbative methods to study the dynamics of the cascade decay to common final states, which features similarities but also noteworthy differences with the case of neutral meson mixing. We show that mixing and oscillations among the nearly degenerate sterile neutrinos can be detected as quantum beats in the distribution of final states produced from their decay. These oscillations would be a telltale signal of mixing between heavy sterile neutrinos. We study in detail the case of two nearly degenerate sterile neutrinos produced in the decay of pseudoscalar mesons and decaying into a purely leptonic "visible" channel: νh→e+e-νa. Possible cosmological implications for the effective number of neutrinos Neff are discussed.

  20. Relic abundance of dark matter in universal extra dimension models with right-handed neutrinos

    SciTech Connect

    Matsumoto, Shigeki; Sato, Joe; Yamanaka, Masato; Senami, Masato

    2009-04-17

    Relic abundance of dark matter is investigated in the framework of universal extra dimension models with right-handed neutrinos. These models are free from the serious Kaluza-Klein (KK) graviton problem that the original universal extra dimension model possesses. The first KK particle of the right-handed neutrino is a candidate for dark matter in this framework. When ordinary neutrino masses are large enough such as the degenerate mass spectrum case, the dark matter relic abundance can change significantly. The scale of the extra dimension consistent with cosmological observations can be 500 GeV in the minimal setup of universal extra dimension models with right-handed neutrinos.

  1. New Limits on Thermally Annihilating Dark Matter from Neutrino Telescopes

    NASA Astrophysics Data System (ADS)

    Lopes, J.; Lopes, I.

    2016-08-01

    We used a consistent and robust solar model to obtain upper limits placed by neutrino telescopes, such as IceCube and Super-Kamiokande, on the dark matter-nucleon scattering cross-section, for a general model of dark matter with a velocity dependent (p-wave) thermally averaged cross-section. In this picture, the Boltzmann equation for the dark matter abundance is numerically solved, satisfying the dark matter density measured from the cosmic microwave background. We show that for lower cross-sections and higher masses, the dark matter annihilation rate drops sharply, resulting in upper bounds on the scattering cross-section that are one order of magnitude above those derived from a velocity independent (s-wave) annihilation cross-section. Our results show that upper limits on the scattering cross-section obtained from dark matter annihilating in the Sun are sensible to the uncertainty in current standard solar models, fluctuating by a maximum of 20% depending on the annihilation channel.

  2. Noncommutative spectral geometry, Bogoliubov transformations and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Vittoria Gargiulo, Maria; Sakellariadou, Mairi; Vitiello, Giuseppe

    2015-07-01

    In this report we show that neutrino mixing is intrinsically contained in Connes’ noncommutatives pectral geometry construction, thanks to the introduction of the doubling of algebra, which is connected to the Bogoliubov transformation. It is known indeed that these transformations are responsible for the mixing, turning the mass vacuum state into the flavor vacuum state, in such a way that mass and flavor vacuum states are not unitary equivalent. There is thus a red thread that binds the doubling of algebra of Connes’ model to the neutrino mixing.

  3. SOLAR NEUTRINO PHYSICS OSCILLATIONS: SENSITIVITY TO THE ELECTRONIC DENSITY IN THE SUN'S CORE

    SciTech Connect

    Lopes, Ilidio; Turck-Chieze, Sylvaine E-mail: ilopes@uevora.pt

    2013-03-01

    Solar neutrinos coming from different nuclear reactions are now detected with high statistics. Consequently, an accurate spectroscopic analysis of the neutrino fluxes arriving on Earth's detectors becomes available, in the context of neutrino oscillations. In this work, we explore the possibility of using this information to infer the radial profile of the electronic density in the solar core. So, we discuss the constraints on the Sun's density and chemical composition that can be determined from solar neutrino observations. This approach constitutes an independent and alternative diagnostic to the helioseismic investigations already done. The direct inversion method, which we propose to obtain the radial solar electronic density profile, is almost independent of the solar model.

  4. Preliminary Measurement of Neutrino Oscillation Parameters By NuMI/MINOS and Calibration Studies for Improving this Measurement

    SciTech Connect

    Symes, Philip Andrew

    2005-11-01

    This thesis explains the origins of neutrinos and their interactions, and the phenomenon of neutrino oscillations. Experiments for measuring neutrino oscillations are mentioned and the experiment investigated in this thesis, the ''Main Injector Neutrino Oscillation Search'', and its neutrino beam, the Fermi National Accelerator Laboratory's ''Neutrinos At The Main Injector'', are described. MINOS is a long baseline (735 km) neutrino oscillation experiment with a near and a far detector, intended to make precision measurements of the atmospheric sector neutrino oscillation parameters. A measurement is made of the ''atmospheric'' neutrino oscillation parameters, {Delta}m{sub 23}{sup 2} and sin {sup 2}(2{theta}{sub 23}), using neutrinos from the NuMI beam. The results of this analysis are compared to measurements at MINOS using neutrinos from the atmosphere and with other experiments. A more detailed method of beam neutrino analysis is discussed, and the extra calibrations needed to perform that analysis properly are described, with special attention paid to two aspects of the calibration, which comprise the bulk of work for this thesis. The light injection calibration system uses LEDs to illuminate the detector readout and provides a normalization of the stability of the detector over time. The hardware and different modi operandi of the system are described. There is a description of installation and commissioning of the system at one of the MINOS detectors. The response normalization of each detector with cosmic ray muons is described. Special attention is paid to the explanation of necessary corrections that must be made to the muon sample in order for the sample to be used to calibrate each detector to the specified accuracy. The performance of the calibration is shown.

  5. Closing in on minimal dark matter and radiative neutrino masses

    NASA Astrophysics Data System (ADS)

    Sierra, D. Aristizabal; Simoes, C.; Wegman, D.

    2016-06-01

    We study one-loop radiative neutrino mass models in which one of the beyond-the-standard model fields is either a hypercharge-zero fermion quintet (minimal dark matter) or a hypercharge-zero scalar septet. By systematically classifying all possible one-loop such models we identify various processes that render the neutral component of these representations (dark matter) cosmologically unstable. Thus, our findings show that these scenarios are in general not reconcilable with dark matter stability unless tiny couplings or additional ad hoc symmetries are assumed, in contrast to minimal dark matter models where stability is entirely due to the standard model gauge symmetry. For some variants based on higher-order loops we find that α2 reaches a Landau pole at rather low scales, a couple orders of magnitude from the characteristic scale of the model itself. Thus, we argue that some of these variations although consistent with dark matter stability and phenomenological constraints are hard to reconcile with perturbativity criteria.

  6. Sterile neutrino oscillations in MINOS and hadron production in pC collisions

    SciTech Connect

    Tinti, Gemma Maria

    2010-01-01

    MINOS is a long baseline neutrino oscillation experiment, starting with a muon-neutrino beam, for the precise measurement of the atmospheric neutrino oscillation parameters |Δm2| and θ23. The Near Detector measures the neutrino flux and spectra before oscillations. The beam propagates for 735 km to the Far Detector, which measures the depleted spectrum after oscillations. The depletion can be interpreted as vμ → vτ oscillations. Subdominant vμ → ve oscillations may be allowed if the mixing angle θ13 ≠ 0. The two detectors are functionally identical in order to cancel systematic errors when using the Near Detector data to constrain the Far Detector prediction. A crucial part of the analysis is the relative calibration between the two detectors, which is known at the 2% level. A calibration procedure to remove the time and temperature dependence of the detector response using through-going cosmic muons is presented here. Although the two-detector approach reduces the systematic uncertainties related to the neutrino flux, a cross check on the neutrino parent meson ratios is performed in this thesis. The cross sections of mesons produced in proton-carbon interactions from the NA49 experiment have been measured and the results have been compared to the MINOS expectations. A neutrino oscillation analysis allowing mixing to a sterile neutrino is performed, under the assumption that the additional mass splitting is Ο(1 eV2). The analysis uses the energy spectrum of the neutral current interaction products, as neutral current interactions are sensitive to sterile neutrino mixing but not to the active flavour neutrino mixing. The neutrino oscillation parameters have been found to be: |Δm2| = 2.43-0.18+0.21 x 10-3 eV2, θ23 = 40.27°-5.17+14.64, θ24 = 0.00°+5.99 and

  7. Long baseline neutrino oscillation experiment at the AGS. Physics design report

    SciTech Connect

    Beavis, D.; Carroll, A.; Chiang, I.; E889 Collaboration

    1995-04-01

    The authors present a design for a multi-detector long baseline neutrino oscillation experiment at the BNL AGS. It has been approved by the BNL-HENP-PAC as AGS Experiment 889. The experiment will search for oscillations in the {nu}{sub {mu}}, disappearance channel and the {nu}{sub {mu}} {leftrightarrow} {nu}{sub e} appearance channel by means of four identical neutrino detectors located 1, 3, 24, and 68km from the AGS neutrino source. Observed depletion of the {nu}{sub {mu}} flux (via quasi-elastic muon neutrino events, {nu}{sub {mu}}n {yields} {mu}{sup {minus}}p) in the far detectors not attended by an observed proportional increase of the {nu}{sub e} flux (via quasi-elastic electron neutrino events, {nu}{sub e}n {yields} e{sup {minus}}p) in those detectors will be prima facie evidence for the oscillation channel {nu}{sub {mu}} {leftrightarrow} {nu}{sub {tau}}. The experiment is directed toward exploration of the region of the neutrino oscillation parameters {Delta}m{sup 2} and sin{sup 2}2{theta}, suggested by the Kamiokande and IMB deep underground detectors but it will also explore a region more than two orders of magnitude larger than that of previous accelerator experiments. The experiment will run in a mode new to BNL. It will receive the fast extracted proton beam on the neutrino target approximately 20 hours per day when the AGS is not filling RHIC. A key aspect of the experimental design involves placing the detectors 1.5 degrees off the center line of the neutrino beam, which has the important advantage that the central value of the neutrino energy ({approx} 1 GeV) and the beam spectral shape are, to a good approximation, the same in all four detectors. The proposed detectors are massive, imaging, water Cherenkov detectors similar in large part to the Kamiokande and IMB detectors. The design has profited from their decade-long experience, and from the detector designs of the forthcoming SNO and SuperKamiokande detectors.

  8. Search for neutrino oscillations in the MINOS experiment by using quasi-elastic interactions

    SciTech Connect

    Piteira, Rodolphe; /Paris U., VI-VII

    2005-09-01

    The enthusiasm of the scientific community for studying oscillations of neutrinos is equaled only by the mass of their detectors. The MINOS experiment determines and compares the near spectrum of muonic neutrinos from the NUMI beam to the far one, in order to measure two oscillation parameters: {Delta}m{sub 23}{sup 2} and sin{sup 2} (2{theta}{sub 23}). The spectra are obtained by analyzing the charged current interactions which difficulty lies in identifying the interactions products (e.g. muons). An alternative method identifying the traces of muons, bent by the magnetic field of the detectors, and determining their energies is presented in this manuscript. The sensitivity of the detectors is optimal for the quasi-elastic interactions, for which a selection method is proposed, to study their oscillation. Even though it reduces the statistics, such a study introduces fewer systematic errors, constituting the ideal method on the long range.

  9. 2540 km: bimagic baseline for neutrino oscillation parameters.

    PubMed

    Dighe, Amol; Goswami, Srubabati; Ray, Shamayita

    2010-12-31

    We show that a source-to-detector distance of 2540 km, motivated recently [S. K. Raut, R. S. Singh, and S. U. Sankar, arXiv:0908.3741] for a narrow band superbeam, offers multiple advantages for a low energy neutrino factory with a detector that can identify muon charge. At this baseline, for any neutrino hierarchy, the wrong-sign muon signal is almost independent of CP violation and θ(13) in certain energy ranges. This allows the identification of the hierarchy in a clean way. In addition, part of the muon spectrum is also sensitive to the CP violating phase and θ(13), so that the same setup can be used to probe these parameters as well. PMID:21231644

  10. Slow control systems of the Reactor Experiment for Neutrino Oscillation

    NASA Astrophysics Data System (ADS)

    Choi, J. H.; Jang, H. I.; Choi, W. Q.; Choi, Y.; Jang, J. S.; Jeon, E. J.; Joo, K. K.; Kim, B. R.; Kim, H. S.; Kim, J. Y.; Kim, S. B.; Kim, S. Y.; Kim, W.; Kim, Y. D.; Ko, Y. J.; Lee, J. K.; Lim, I. T.; Pac, M. Y.; Park, I. G.; Park, J. S.; Park, R. G.; Seo, H. K.; Seo, S. H.; Shin, C. D.; Siyeon, K.; Yeo, I. S.; Yu, I.

    2016-02-01

    The RENO experiment has been in operation since August 2011 to measure reactor antineutrino disappearance using identical near and far detectors. For accurate measurements of neutrino mixing parameters and efficient data taking, it is crucial to monitor and control the detector in real time. Environmental conditions also need to be monitored for stable operation of detectors as well as for safety reasons. In this paper, we report the design, hardware, operation, and performance of the slow control system.

  11. Pairing effects on neutrino transport in low-density stellar matter

    NASA Astrophysics Data System (ADS)

    Burrello, S.; Colonna, M.; Matera, F.

    2016-07-01

    We investigate the impact of pairing correlations on neutrino transport in stellar matter. Our analysis is extended to nuclear matter conditions where large density fluctuations may develop, associated with the onset of the liquid-vapor phase transition, and where clustering phenomena occur. Within a thermodynamical treatment, we show that at moderate temperatures, where pairing effects are still active, the scattering of neutrinos in the nuclear medium is significantly affected by pairing correlations, which increase the neutrino trapping, thus modifying the cooling mechanism, by neutrino emission, of protoneutron stars.

  12. A search for Secluded Dark Matter in the Sun with the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Albert, A.; André, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bou-Cabo, M.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Fehn, K.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaš, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Riccobene, G.; Roensch, K.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Sánchez-Losa, A.; Taiuti, M.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.

    2016-05-01

    A search for Secluded Dark Matter annihilation in the Sun using 2007–2012 data of the ANTARES neutrino telescope is presented. Three different cases are considered: a) detection of dimuons that result from the decay of the mediator, or neutrino detection from: b) mediator that decays into a dimuon and, in turn, into neutrinos, and c) mediator that decays directly into neutrinos. As no significant excess over background is observed, constraints are derived on the dark matter mass and the lifetime of the mediator.

  13. Chaos, determinacy and fractals in active-sterile neutrino oscillations in the early universe

    SciTech Connect

    Abazajian, Kevork N; Agrawal, Prateek E-mail: apr@umd.edu

    2008-10-15

    The possibility of light sterile neutrinos allows for the resonant production of lepton number in the early universe through matter-affected neutrino mixing. For a given mixing of the active and sterile neutrino states it has been found that the lepton number generation process is chaotic and strongly oscillatory. We undertake a new study of the sensitivity of this process to initial conditions through the quantum rate equations. We confirm the chaoticity of the process in this solution, and moreover find that the resultant lepton number and the sign of the asymmetry produce a fractal in the parameter space of mass, mixing angle and initial baryon number. This has implications for future searches for sterile neutrinos, where arbitrarily high sensitivity may not be determinate in forecasting the lepton number of the universe.

  14. Neutrino Scattering Uncertainties and their Role in Long Baseline Oscillation Experiments

    SciTech Connect

    D.A. Harris; G. Blazey; Arie Bodek; D. Boehnlein; S. Boyd; William Brooks; Antje Bruell; Howard S. Budd; R. Burnstein; D. Casper; A. Chakravorty; Michael Christy; Jesse Chvojka; M.A.C. Cummings; P. deBarbaro; D. Drakoulakos; J. Dunmore; Rolf Ent; Hugh Gallagher; David Gaskell; Ronald Gilman; Charles Glashausser; Wendy Hinton; Xiaodong Jiang; T. Kafka; O. Kamaev; Cynthia Keppel; M. Kostin; Sergey Kulagin; Gerfried Kumbartzki; Steven Manly; W.A. Mann; Kevin Mcfarland-porter; Wolodymyr Melnitchouk; Jorge Morfin; D. Naples; John Nelson; Gabriel Niculescu; Maria-ioana Niculescu; W. Oliver; Michael Paolone; Emmanuel Paschos; A. Pla-Dalmau; Ronald Ransome; C. Regis; P. Rubinov; V. Rykalin; Willis Sakumoto; P. Shanahan; N. Solomey; P. Spentzouris; P. Stamoulis; G. Tzanakos; Stephen Wood; F.X. Yumiceva; B. Ziemer; M. Zois

    2004-10-01

    The field of oscillation physics is about to make an enormous leap forward in statistical precision: first through the MINOS experiment in the coming year, and later through the NOvA and T2K experiments. Because of the relatively poor understanding of neutrino interactions in the energy ranges of these experiments, there are systematics that can arise in interpreting far detector data that can be as large as or even larger than the expected statistical uncertainties. We describe how these systematic errors arise, and how specific measurements in a dedicated neutrino scattering experiment like MINERvA can reduce the cross section systematic errors to well below the statistical errors.

  15. Numerical implementation of lepton-nucleus interactions and its effect on neutrino oscillation analysis

    NASA Astrophysics Data System (ADS)

    Jen, C.-M.; Ankowski, A. M.; Benhar, O.; Furmanski, A. P.; Kalousis, L. N.; Mariani, C.

    2014-11-01

    We discuss the implementation of the nuclear model based on realistic nuclear spectral functions in the GENIE neutrino interaction generator. Besides improving on the Fermi gas description of the nuclear ground state, our scheme involves a new prescription for Q2 selection, meant to efficiently enforce energy-momentum conservation. The results of our simulations, validated through comparison to electron scattering data, have been obtained for a variety of target nuclei, ranging from carbon to argon, and cover the kinematical region in which quasielastic scattering is the dominant reaction mechanism. We also analyze the influence of the adopted nuclear model on the determination of neutrino oscillation parameters.

  16. VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS FOR PRECISE MEASURMENTS OF OSCILLATION PARAMETERS AND SEARCH FOR N MU YIELDS N EPSILON.

    SciTech Connect

    DIWAN,M.; MARCIANO,W.; WENG,W.; BEAVIS,D.; BRENNAN,M.; CHEN,M.C.; FERNOW,R.; ET AL

    2002-10-18

    Brookhaven National Laboratory and collaborators started a neutrino working group to identify new opportunities in the field of neutrino oscillations and explore how our laboratory facilities can be used to explore this field of research. The memo to the working group and the charge are included in Appendix I. This report is the result of the deliberations of the working group. Previously, we wrote a letter of intent to build a new high intensity neutrino beam at BNL. A new intense proton beam will be used to produce a conventional horn focused neutrino beam directed at a detector located in either the Homestake mine in Lead, South Dakota at 2540 km or the Waste Isolation Pilot Plant (WIPP) in Carlsbad, NM at 2880 km. As a continuation of the study that produced the letter of intent, this report examines several items in more detail. We mainly concentrate on the use of water Cherenltov detectors because of their size, resolution, and background rejection capability, and cost. We examine the prospects of building such a detector in the Homestake mine. The accelerator upgrade will be carried out in phases. We expect the first phase to yield a 0.4 MW proton beam and the second phase to result in a 1.0 MW beam. The details of this upgrade will be reported in a companion report. In this report we assume accelerator intensity of 1 MW for calculating event rates and spectra. We also assume a total experimental duration of 5 years with running time of 10{sup 7} seconds per year. We examine the target station and the horn produced neutrino beam with focus on two topics: target and horn design for a 1 MW beam and the broad band spectrum of neutrinos from a 28 GeV proton beam.

  17. Precise study of the atmospheric neutrino oscillation pattern using Super-Kamiokande I and II

    NASA Astrophysics Data System (ADS)

    Dufour, Fanny Maude

    Neutrino oscillation arises because the mass eigenstates of neutrinos are not identical to the flavor eigenstates, and it is described by the PMNS (Pontecorvo, Maki, Nakagawa and Sakata) flavor mixing matrix. This matrix contains 6 parameters: 3 angles, 2 mass splittings and one CP violating phase. Using the atmospheric neutrino data collected by the Super-Kamiokande water Cherenkov detector, we can measure two of these parameters, Dm223 and sin2 2theta23, which govern the oscillation of numu → nutau. The L/E analysis studies the ratio of flight length (L) to energy (E) and is the only analysis which is able to resolve the expected oscillatory pattern of the survival probability: P(numu → numu) = 1 - sin 2 (2theta) x sin2 (1.27 x Deltam 2 LkmE GeV ). To observe this oscillation pattern, we divide the L/E distribution of muon neutrino data by a normalized unoscillated set of Monte Carlo. Events used in this analysis need good flight length and energy resolution, therefore strict resolution cuts are applied. Hence, the data sample is smaller than the sample used in the other Super-Kamiokande analysis [1]. Despite the smaller sample, the L/E analysis gives a stronger constraint on Dm223 . This thesis covers the L/E analysis of the Super-Kamiokande atmospheric data collected during the Super-Kamiokande I (SK1: 1996-2001, 1489 days) and Super-Kamiokande II (SK2: 2003-2005, 804 days) data-taking periods. The final values of the oscillation parameters for the combined SK1+SK2 datasets, at 90% confidence level, are sin2 2theta 23 > 0.94 and 1.85 x 10-3 eV 2 < Dm223 < 2.65 x 10-3 eV2. The chi2 obtained with the oscillation hypothesis is lower than when we assume other models like neutrino decay (3.7sigma) or neutrino decoherence (4.7sigma). A significant part of this work was the improvement of the partially contained (PC) event sample. This sample consists of neutrino events in which the outgoing charged lepton exits the inner detector and deposits energy in the outer

  18. Detecting electron neutrinos from solar dark matter annihilation by JUNO

    NASA Astrophysics Data System (ADS)

    Guo, Wan-Lei

    2016-01-01

    We explore the electron neutrino signals from light dark matter (DM) annihilation in the Sun for the large liquid scintillator detector JUNO. In terms of the spectrum features of three typical DM annihilation channels χχ → νbar nu, τ+τ-, bbar b, we take two sets of selection conditions to calculate the expected signals and atmospheric neutrino backgrounds based on the Monte Carlo simulation data. Then the JUNO sensitivities to the spin independent DM-nucleon and spin dependent DM-proton cross sections are presented. It is found that the JUNO projected sensitivities are much better than the current spin dependent direct detection experimental limits for the νbar nu and τ+τ- channels. In the spin independent case, the JUNO will give the better sensitivity to the DM-nucleon cross section than the LUX and CDMSlite limits for the νbar nu channel with the DM mass lighter than 6.5 GeV . If the νbar nu or τ+τ- channel is dominant, the future JUNO results are very helpful for us to understand the tension between the DAMA annual modulation signal and other direct detection exclusions.

  19. Neutrinos and dark matter in the Black Hills

    NASA Astrophysics Data System (ADS)

    McMahan Norris, Margaret; Sayler, Bentley

    2010-02-01

    Where in the U.S. could you walk into a hardware store and be asked about neutrinos? It happens regularly in the Black Hills of South Dakota, where preliminary design is in progress for the Deep Underground Science and Engineering Laboratory (DUSEL), a planned NSF Major Research Experimental Facility Construction (MREFC) initiative to be located at the former Homestake gold mine in Lead, SD. DUSEL has physicists buzzing too, as the particle, astro-, and nuclear physics communities have all identified the need for a new laboratory deep beneath the Earth's surface to address some of the most compelling, transformational science at the frontiers of their disciplines. Elusive particles such as neutrinos and WIMPS (a possible candidate for dark matter) -- though they spark the imagination - are equally elusive when trying to explain to students and the public. That will be the task of the Sanford Center for Science Education, planned to be the education arm of DUSEL. Early prototypes of future programs at the education center are now under development, ranging from professional development for teachers to classroom tours to working with American Indian educators. These programs, which are building capacity for the future education center, will be discussed. )

  20. Results on θ13 Neutrino Oscillations from Reactor Experiments

    NASA Astrophysics Data System (ADS)

    Kim, Soo-Bong

    2014-03-01

    Definitive measurements of the smallest neutrino mixing angle θ13 were made by Daya Bay, Double Chooz and RENO in 2012, based on the disappearance of electron antineutrinos emitted from reactors. The new generation reactor experiments have significantly improved a sensitivity for θ13 down to the sin2(2θ13)~0.01 level using two identical detectors of 10 ~ 40 tons at near (300 ~ 400 m) and far (1 ~ 2 km) locations. The θ13 measurements by the three reactor experiments are presented with their future expected sensitivities.

  1. Neutrino Tomography Learning About The Earth's Interior Using The Propagation Of Neutrinos

    NASA Astrophysics Data System (ADS)

    Winter, Walter

    2006-12-01

    Because the propagation of neutrinos is affected by the presence of Earth matter, it opens new possibilities to probe the Earth’s interior. Different approaches range from techniques based upon the interaction of high energy (above TeV) neutrinos with Earth matter, to methods using the MSW effect on the oscillations of low energy (MeV to GeV) neutrinos. In principle, neutrinos from many different sources (sun, atmosphere, supernovae, beams etc.) can be used. In this talk, we summarize and compare different approaches with an emphasis on more recent developments. In addition, we point out other geophysical aspects relevant for neutrino oscillations.

  2. Study of muon neutrino and muon antineutrino disappearance with the NOvA neutrino oscillation experiment

    SciTech Connect

    Pawloski, Gregory

    2014-06-30

    The primary goal of this working group is to study the disappearance rate of νμ charged current events in order to measure the mixing angle θ23 and the magnitude of the neutrino mass square splitting Δm 232.

  3. Dark matter from PeV physics and the neutrino sector

    NASA Astrophysics Data System (ADS)

    Shakya, Bibhushan; Roland, Samuel B.; Wells, James D.

    2016-06-01

    It is well known that the neutrino sector can provide a dark matter candidate in the form of a light sterile neutrino. This note discusses a framework that naturally leads to light (keV-GeV) sterile neutrino dark matter produced via the freeze-in mechanism: a modified, low energy seesaw with the right-handed neutrinos charged under a new symmetry broken by a PeV scale vacuum expectation value. This framework can accommodate the recently observed 3.5 keV X-ray line, while a straightforward extension, using the new symmetry and the PeV energy scale, can explain the PeV energy neutrino events at IceCube. Together, these can therefore be taken as hints of the existence of a PeV scale neutrino sector.

  4. Chiral gauge theories and a dirac neutrino - Dark matter connection

    NASA Astrophysics Data System (ADS)

    Hernandez, Daniel

    2016-06-01

    It is proposed that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. A new gauge symmetry U(1)ν is required if light fermionic new states are to exist. Anomaly cancellations mandate the existence of several new fields with nontrivial U(1)ν charges. A general technique to write down chiral-fermions-only models that are at least anomaly-free under a U(1) gauge symmetry is described. A concrete example that provides a Dark Matter candidate and leads to parametrically small Dirac neutrino masses is further developed.

  5. Missing energy and the measurement of the CP-violating phase in neutrino oscillations

    SciTech Connect

    Ankowski, Artur M.; Coloma, Pilar; Huber, Patrick; Mariani, Camillo; Vagnoni, Erica

    2015-11-30

    In the next generation of long-baseline neutrino oscillation experiments aiming to determine the charge-parity-violating phase δCP in the appearance channel, fine-grained time-projection chambers are expected to play an important role. In this study, we analyze an influence of realistic detector capabilities on the δCP sensitivity for a setup similar to that of the Deep Underground Neutrino Experiment. We find that the effect of the missing energy carried out by undetected particles is sizable. Although the reconstructed neutrino energy can be corrected for the missing energy, the accuracy of such procedure has to exceed 20%, to avoid a sizable bias in the extracted δCP value.

  6. Missing energy and the measurement of the CP-violating phase in neutrino oscillations

    DOE PAGESBeta

    Ankowski, Artur M.; Coloma, Pilar; Huber, Patrick; Mariani, Camillo; Vagnoni, Erica

    2015-11-30

    In the next generation of long-baseline neutrino oscillation experiments aiming to determine the charge-parity-violating phase δCP in the appearance channel, fine-grained time-projection chambers are expected to play an important role. In this study, we analyze an influence of realistic detector capabilities on the δCP sensitivity for a setup similar to that of the Deep Underground Neutrino Experiment. We find that the effect of the missing energy carried out by undetected particles is sizable. Although the reconstructed neutrino energy can be corrected for the missing energy, the accuracy of such procedure has to exceed 20%, to avoid a sizable bias inmore » the extracted δCP value.« less

  7. Solar neutrinos as background in dark matter searches involving electron detection

    NASA Astrophysics Data System (ADS)

    Thomas, A. W.; Vergados, J. D.

    2016-07-01

    In the present work we estimate the potential background of solar neutrinos on electron detectors. These detectors are considered relevant for detecting light dark matter particles in the MeV region, currently sought by experiments. We find that the copious low energy pp neutrinos are a dangerous background at the energies involved in these experiments, in fact close to the anticipated event rate, while the more energetic Boron neutrinos are harmless.

  8. IceCube Events from Decaying Dark Matter with Neutrino Portal

    NASA Astrophysics Data System (ADS)

    Ko, P.; Tang, Yong

    2016-07-01

    IceCube has observed several PeV neutrino events whose astrophysical origin has not been identified. In this proceeding, we discuss heavy decaying dark matter may be responsible for these neutrinos. Dark matter χ is constructed to communicate with standard model particles through the neutrino-portal interaction. We calculate both total and differential decay width for the dominant three-body decay of dark matter and show that to fit the data, the required mass is around 𝒪(10 PeV) and lifetime is about 1028s.

  9. Probing dark matter annihilation to primary neutrinos with IceCube

    SciTech Connect

    Allahverdi, Rouzbeh

    2014-06-24

    We investigate the prospects for discovery and discrimination of dark matter annihilation into primary neutrinos from other final states at IceCube/DeepCore. By taking detector considerations into account, we perform a fit to obtain sensitivity limits for the primary neutrino final states from annihilation of dark matter particles gravitationally captured inside the Sun. We show that for dark matter in the 50 GeV–1 TeV mass range, primary neutrinos can be distinguished from other final states at a statistically significant level with multi-year data from IceCube/DeepCore.

  10. Systematic uncertainties in long-baseline neutrino oscillations for large θ₁₃

    SciTech Connect

    Coloma, Pilar; Huber, Patrick; Kopp, Joachim; Winter, Walter

    2013-02-01

    We study the physics potential of future long-baseline neutrino oscillation experiments at large θ₁₃, focusing especially on systematic uncertainties. We discuss superbeams, \\bbeams, and neutrino factories, and for the first time compare these experiments on an equal footing with respect to systematic errors. We explicitly simulate near detectors for all experiments, we use the same implementation of systematic uncertainties for all experiments, and we fully correlate the uncertainties among detectors, oscillation channels, and beam polarizations as appropriate. As our primary performance indicator, we use the achievable precision in the measurement of the CP violating phase $\\deltacp$. We find that a neutrino factory is the only instrument that can measure $\\deltacp$ with a precision similar to that of its quark sector counterpart. All neutrino beams operating at peak energies ≳2 GeV are quite robust with respect to systematic uncertainties, whereas especially \\bbeams and \\thk suffer from large cross section uncertainties in the quasi-elastic regime, combined with their inability to measure the appearance signal cross sections at the near detector. A noteworthy exception is the combination of a γ =100 \\bbeam with an \\spl-based superbeam, in which all relevant cross sections can be measured in a self-consistent way. This provides a performance, second only to the neutrino factory. For other superbeam experiments such as \\lbno and the setups studied in the context of the \\lbne reconfiguration effort, statistics turns out to be the bottleneck. In almost all cases, the near detector is not critical to control systematics since the combined fit of appearance and disappearance data already constrains the impact of systematics to be small provided that the three active flavor oscillation framework is valid.

  11. Improved search for muon-neutrino to electron-neutrino oscillations in MINOS

    DOE PAGESBeta

    Adamson, P.

    2011-10-27

    The authors report the results of a search for νe appearance in νμ beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 x 1020 protons on the NuMI target at Fermilab, they find that 2 sin2 (θ23 sin2 (θ13) < 0.12 (0.20) at 90% confidence level for δ = 0 and the normal (inverted) neutrino mass hierarchy, with a best fit of 2 sin2θ23) sin 2 (2θ13) = 0.041-0.031 +0.047 (0.079-0.053 +0.071). The θ13= 0 hypothesis is disfavored by the MINOS data at the 89% confidence level.

  12. Particle physics confronts the solar neutrino problem

    SciTech Connect

    Pal, P.B.

    1991-06-01

    This review has four parts. In Part I, we describe the reactions that produce neutrinos in the sun and the expected flux of those neutrinos on the earth. We then discuss the detection of these neutrinos, and how the results obtained differ from the theoretical expectations, leading to what is known as the solar neutrino problem. In Part II, we show how neutrino oscillations can provide a solution to the solar neutrino problem. This includes vacuum oscillations, as well as matter enhanced oscillations. In Part III, we discuss the possibility of time variation of the neutrino flux and how a magnetic moment of the neutrino can solve the problem. WE also discuss particle physics models which can give rise to the required values of magnetic moments. In Part IV, we present some concluding remarks and outlook for the recent future.

  13. Neutrino oscillations with a proton driver upgrade and an off-axis detector: A Case study

    SciTech Connect

    Barenboim, Gabriela; De Gouvea, Andre; Szleper, Michal; Velasco, Mayda

    2002-04-01

    We study the physics capabilities of the NuMI beamline with an off-axis highly-segmented iron scintillator detector and with the inclusion of the currently under study proton driver upgrade. We focus on the prospects for the experimental determination of the remaining neutrino oscillation parameters, assuming different outcomes for experiments under way or in preparation. An optimization of the beam conditions and detector location for the detection of the nu_mu to nu_e transitions is discussed. Different physics scenarios were considered, depending on the actual solution of the solar neutrino puzzle. If KamLAND measures Delta m^2_solar, we find it possible to measure both |U_{e3}|^2 and the CP violating phase delta within a viable exposure time, assuming a realistic detector and a complete data analysis. Exposure to both neutrino and antineutrino beams is necessary. We can, in addition, shed light on Delta m^2_solar if its value is at the upper limit of KamLAND sensitivity (i.e. the precise value of Delta m^2_solar remains unknown even after KamLAND). If the solar neutrino solution is not in the LMA region, we can measure |U_{e3}|^2 and determine the neutrino mass hierarchy. The existence of the proton driver is vital for the feasibility of most of these measurements.

  14. Neutrinos: Nature's Identity Thieves?

    SciTech Connect

    Lincoln, Don

    2013-07-11

    The oscillation of neutrinos from one variety to another has long been suspected, but was confirmed only about 15 years ago. In order for these oscillations to occur, neutrinos must have a mass, no matter how slight. Since neutrinos have long been thought to be massless, in a very real way, this phenomena is a clear signal of physics beyond the known. In this video, Fermilab's Dr Don Lincoln explains how we know it occurs and hints at the rich experimental program at several international laboratories designed to understand this complex mystery.

  15. Neutrinos: Nature's Identity Thieves?

    ScienceCinema

    Lincoln, Don

    2014-08-07

    The oscillation of neutrinos from one variety to another has long been suspected, but was confirmed only about 15 years ago. In order for these oscillations to occur, neutrinos must have a mass, no matter how slight. Since neutrinos have long been thought to be massless, in a very real way, this phenomena is a clear signal of physics beyond the known. In this video, Fermilab's Dr Don Lincoln explains how we know it occurs and hints at the rich experimental program at several international laboratories designed to understand this complex mystery.

  16. Neutrinos: Nature's Identity Thieves?

    ScienceCinema

    Dr. Don Lincoln

    2013-07-22

    The oscillation of neutrinos from one variety to another has long been suspected, but was confirmed only about 15 years ago. In order for these oscillations to occur, neutrinos must have a mass, no matter how slight. Since neutrinos have long been thought to be massless, in a very real way, this phenomena is a clear signal of physics beyond the known. In this video, Fermilab's Dr Don Lincoln explains how we know it occurs and hints at the rich experimental program at several international laboratories designed to understand this complex mystery.

  17. Investigation of alternative mechanisms to neutrino oscillations in the MINOS experiment; Investigacao de Mecanismos Alternativos a Oscilacao de Neutrinos no Experimentos MINOS

    SciTech Connect

    de Abreu Barbosa Coelho, Joao

    2012-01-01

    The neutrino oscillation model is very successful in explaining a large variety of experiments. The model is based on the premise that the neutrinos that interact through the weak force via charged current are not mass eigenstates, but a superposition of them. In general, a quantum superposition is subject to loss of coherence, so that pure states tend toward mixed states. This type of evolution is not possible within the context of isolated quantum systems because the evolution is unitary and, therefore, is invariant under time reversal. By breaking unitarity, an arrow of time is introduced and the characteristic effect for neutrinos is a damping of oscillations. In this thesis, some phenomenological decoherence and decay models are investigated, which could be observed by MINOS, a neutrino oscillation experiment that consists of measuring the neutrino flux produced in a particle accelerator 735 km away. We analyse the disappearance of muon neutrinos in MINOS. Information from other experiments is used to constrain the number of parameters, leaving only one extra parameter in each model. We assume a power law energy dependence of the decoherence parameter. The official MINOS software and simulation are used to obtain the experiment's sensitivities to the effects of unitarity breaking considered.

  18. Neutrino and dark matter physics with sub-KeV Germanium detectors

    NASA Astrophysics Data System (ADS)

    Li, Hau Bin; (TEXONO collaboration

    2016-05-01

    Germanium detectors with sub-keV sensitivities [1, 2, 3] offer a unique opportunity to study neutrino interactions and properties [4] as well as to search for light WIMP Dark Matter [5, 6]. The TEXONO and CDEX Collaborations have been pursuing this research program at the Kuo-Sheng Neutrino Laboratory in Taiwan and in the China Jinping Underground Laboratory in China. We will present highlights of the detector R&D program which allow us to experimental probe this new energy window. The results, status and plans of our neutrino physics program will be discussed, with focus on the quest on neutrino-nucleus coherent scattering.

  19. Theory of neutrino emission from nucleon-hyperon matter in neutron stars: angular integrals

    NASA Astrophysics Data System (ADS)

    Kaminker, A. D.; Yakovlev, D. G.; Haensel, P.

    2016-08-01

    Investigations of thermal evolution of neutron stars with hyperon cores require neutrino emissivities for many neutrino reactions involving strongly degenerate particles (nucleons, hyperons, electrons, muons). We calculate the angular integrals In (over orientations of momenta of n degenerate particles) for major neutrino reactions with n=3, 4, 5 at all possible combinations of particle Fermi momenta. The integrals In are necessary ingredients for constructing a uniform database of neutrino emissivities in dense nucleon-hyperon matter. The results can also be used in many problems of physical kinetics of strongly degenerate systems.

  20. Influence of ~7 keV sterile neutrino dark matter on the process of reionization

    NASA Astrophysics Data System (ADS)

    Rudakovskyi, Anton; Iakubovskyi, Dmytro

    2016-06-01

    Recent reports of a weak unidentified emission line at ~3.5 keV found in spectra of several matter-dominated objects may give a clue to resolve the long-standing problem of dark matter. One of the best physically motivated particle candidate able to produce such an extra line is sterile neutrino with the mass of ~7 keV . Previous works show that sterile neutrino dark matter with parameters consistent with the new line measurement modestly affects structure formation compared to conventional cold dark matter scenario. In this work, we concentrate for the first time on contribution of the sterile neutrino dark matter able to produce the observed line at ~3.5 keV, to the process of reionization. By incorporating dark matter power spectra for ~7 keV sterile neutrinos into extended semi-analytical `bubble' model of reionization we obtain that such sterile neutrino dark matter would produce significantly sharper reionization compared to widely used cold dark matter models, impossible to `imitate' within the cold dark matter scenario under any reasonable choice of our model parameters, and would have a clear tendency of lowering both the redshift of reionization and the electron scattering optical depth (although the difference is still below the existing model uncertainties). Further dedicated studies of reionization (such as 21 cm measurements or studies of kinetic Sunyaev-Zeldovich effect) will thus be essential for reconstruction of particle candidate responsible the ~3.5 keV line.

  1. Measurement of Neutrino Oscillation Parameters Using Anti-fiducial Charged Current Events in MINOS

    SciTech Connect

    Strait, Matthew Levy

    2010-09-01

    Abstract The Main Injector Neutrino Oscillation Search (MINOS) obse rves the disappearance of muon neutrinos as they propagate in the long baseline Neutri nos at the Main Injector (NuMI) beam. MINOS consists of two detectors. The near detector sam ples the initial composition of the beam. The far detector, 735 km away, looks for an energy-d ependent deficit in the neutrino spectrum. This energy-dependent deficit is interpreted as q uantum mechanical oscillations be- tween neutrino flavors. A measurement is made of the effective two-neutrino mixing parameters ∆ m 2 ≈ ∆ m 2 23 and sin 2 2 θ ≈ sin 2 2 θ 23 . The primary MINOS analysis uses charged current events in the fiducial volume of the far detector. This analysis uses the roughly equal-sized sample of events that fails the fiducial cut, consisting of interact ions outside the fiducial region of the detector and in the surrounding rock. These events provide a n independent and complementary measurement, albeit weaker due to incomplete reconstructi on of the events. This analysis reports on an exposure of 7 . 25 × 10 20 protons-on-target. Due to poor energy resolution, the meas urement of sin 2 2 θ is much weaker than established results, but the measuremen t of sin 2 2 θ > 0 . 56 at 90% confidence is consistent with the accepted value. The measur ement of ∆ m 2 is much stronger. Assuming sin 2 2 θ = 1 , ∆ m 2 = (2 . 20 ± 0 . 18[stat] ± 0 . 14[syst]) × 10 − 3 eV 2 .

  2. Constraining sterile neutrino warm dark matter with Chandra observations of the Andromeda galaxy

    SciTech Connect

    Watson, Casey R.; Polley, Nicholas K.; Li, Zhiyuan E-mail: zyli@astro.ucla.edu

    2012-03-01

    We use the Chandra unresolved X-ray emission spectrum from a 12'–28' (2.8–6.4 kpc) annular region of the Andromeda galaxy to constrain the radiative decay of sterile neutrino warm dark matter. By excising the most baryon-dominated, central 2.8 kpc of the galaxy, we reduce the uncertainties in our estimate of the dark matter mass within the field of view and improve the signal-to-noise ratio of prospective sterile neutrino decay signatures relative to hot gas and unresolved stellar emission. Our findings impose the most stringent limit on the sterile neutrino mass to date in the context of the Dodelson-Widrow model, m{sub s} < 2.2 keV (95% C.L.). Our results also constrain alternative sterile neutrino production scenarios at very small active-sterile neutrino mixing angles.

  3. Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Albert, A.; André, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Fehn, K.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Riccobene, G.; Roensch, K.; Saldaña, M.; Samtleben, D. F. E.; Sánchez-Losa, A.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tönnis, C.; Trovato, A.; Tselengidou, M.; Turpin, D.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.

    2016-08-01

    A search for muon neutrinos originating from dark matter annihilations in the Sun is performed using the data recorded by the ANTARES neutrino telescope from 2007 to 2012. In order to obtain the best possible sensitivities to dark matter signals, an optimisation of the event selection criteria is performed taking into account the background of atmospheric muons, atmospheric neutrinos and the energy spectra of the expected neutrino signals. No significant excess over the background is observed and 90% C.L. upper limits on the neutrino flux, the spin-dependent and spin-independent WIMP-nucleon cross-sections are derived for WIMP masses ranging from 50 GeV to 5 TeV for the annihilation channels WIMP + WIMP → b b bar ,W+W- and τ+τ-.

  4. Quantum dissipation in a neutrino system propagating in vacuum and in matter

    NASA Astrophysics Data System (ADS)

    Guzzo, Marcelo M.; de Holanda, Pedro C.; Oliveira, Roberto L. N.

    2016-07-01

    Considering the neutrino state like an open quantum system, we analyze its propagation in vacuum or in matter. After defining what can be called decoherence and relaxation effects, we show that in general the probabilities in vacuum and in constant matter can be written in a similar way, which is not an obvious result for such system. From this result, we analyze the situation where neutrino evolution satisfies the adiabatic limit and use this formalism to study solar neutrinos. We show that the decoherence effect may not be bounded by the solar neutrino data and review some results in the literature, in particular the current results where solar neutrinos were used to put bounds on decoherence effects through a model-dependent approach. We conclude explaining how and why these models are not general and we reinterpret these constraints.

  5. Improved search for muon-neutrino to electron-neutrino oscillations in MINOS

    SciTech Connect

    Adamson, P.

    2011-10-27

    The authors report the results of a search for νe appearance in νμ beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 x 1020 protons on the NuMI target at Fermilab, they find that 2 sin223 sin213) < 0.12 (0.20) at 90% confidence level for δ = 0 and the normal (inverted) neutrino mass hierarchy, with a best fit of 2 sin2θ23) sin 2 (2θ13) = 0.041-0.031 +0.047 (0.079-0.053 +0.071). The θ13= 0 hypothesis is disfavored by the MINOS data at the 89% confidence level.

  6. Parameter degeneracy in neutrino oscillation — Solution network and structural overview

    NASA Astrophysics Data System (ADS)

    Minakata, Hisakazu; Uchinami, Shoichi

    2010-04-01

    It is known that there is a phenomenon called “parameter degeneracy” in neutrino oscillation measurement of lepton mixing parameters; A set of the oscillation probabilities, e.g., P( ν μ → ν e ) and its CP-conjugate Pleft( {{{bar ν }_μ } to {{bar ν }_e}} right) at a particular neutrino energy does not determine uniquely the values of θ 13 and δ. With use of the approximate form of the oscillation probability á la Cervera et al., a complete analysis of the eightfold parameter degeneracy is presented. We propose a unified view of the various types of the degeneracy as invariance of the oscillation probabilities under discrete mappings of the mixing parameters. Explicit form of the mapping is obtained either by symmetry argument, or by deriving exact analytic expressions of all the degeneracy solutions for a given true solution. Due to the one-to-one mapping structure the degeneracy solutions are shown to form a network. We extend our analysis into the parameter degeneracy in T- and CPT-conjugate measurement as well as to the setup with the golden and the silver channels, P( ν e → ν μ ) and P( ν e → ν τ ). Some characteristic features of the degeneracy solutions in CP-conjugate measurement, in particular their energy dependences, are illuminated by utilizing the explicit analytic solutions.

  7. Matter Power Spectrum in f(R) Gravity with Massive Neutrinos

    NASA Astrophysics Data System (ADS)

    Motohashi, H.; Starobinsky, A. A.; Yokoyama, J.

    2010-09-01

    The effect of massive neutrinos on matter power spectrum is discussed in the context of f(R) gravity. It is shown that the anomalous growth of density fluctuations on small scales due to the scalaron force can be compensated by the free streaming of neutrinos. As a result, models that predict observable deviation of the equation-of-state parameter w_{DE} from w_{DE} = -1 can be reconciled with observations of matter clustering if the total neutrino mass is O (0.5 eV).

  8. Coupled Dirac fermions and neutrino-like oscillations in twisted bilayer graphene.

    PubMed

    Xian, Lede; Wang, Z F; Chou, M Y

    2013-11-13

    The low-energy quasiparticles in graphene can be described by a Dirac-Weyl Hamiltonian for massless fermions, hence graphene has been proposed to be an effective medium to study exotic phenomena originally predicted for relativistic particle physics, such as Klein tunneling and Zitterbewegung. In this work, we show that another important particle-physics phenomenon, the neutrino oscillation, can be studied and observed in a particular graphene system, namely, twisted bilayer graphene. It has been found that graphene layers grown epitaxially on SiC or by the chemical vapor deposition method on metal substrates display a stacking pattern with adjacent layers rotated by an angle with respect to each other. The quasiparticle states in two distinct graphene layers act as neutrinos with two flavors, and the interlayer interaction between them induces an appreciable coupling between these two "flavors" of massless fermions, leading to neutrino-like oscillations. In addition, our calculation shows that anisotropic transport properties manifest in a specific energy window, which is accessible experimentally in twisted bilayer graphene. Combining two graphene layers enables us to probe the rich physics involving multiple interacting Dirac fermions. PMID:24079848

  9. Prospects for reconstruction of leptonic unitarity quadrangle and neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Verma, Surender; Bhardwaj, Shankita

    2016-06-01

    After the observation of non-zero θ13 the goal has shifted to observe CP violation in the leptonic sector. Neutrino oscillation experiments can, directly, probe the Dirac CP phases. Alternatively, one can measure CP violation in the leptonic sector using Leptonic Unitarity Quadrangle (LUQ). The existence of Standard Model (SM) gauge singlets - sterile neutrinos - will provide additional sources of CP violation. We investigate the connection between neutrino survival probability and rephasing invariants of the 4 × 4 neutrino mixing matrix. In general, LUQ contain eight geometrical parameters out of which five are independent. We obtain CP asymmetry (Pνf→νf‧ -Pνbarf→νbarf‧) in terms of these independent parameters of the LUQ and search for the possibilities of extracting information on these independent geometrical parameters in short baseline (SBL) and long baseline (LBL) experiments, thus, looking for constructing LUQ and possible measurement of CP violation. We find that it is not possible to construct LUQ using data from LBL experiments because CP asymmetry is sensitive to only three of the five independent parameters of LUQ. However, for SBL experiments, CP asymmetry is found to be sensitive to all five independent parameters making it possible to construct LUQ and measure CP violation.

  10. Prospects for detecting dark matter with neutrino telescopes in intermediate mass black hole scenarios

    SciTech Connect

    Bertone, Gianfranco

    2006-05-15

    Current strategies of indirect dark matter detection with neutrino telescopes are based on the search for high-energy neutrinos from the solar core or from the center of the Earth. Here, we propose a new strategy based on the detection of neutrinos from dark matter annihilations in mini-spikes around intermediate mass black holes. Neutrino fluxes, in this case, depend on the annihilation cross-section of dark matter particles, whereas solar and terrestrial fluxes are sensitive to the scattering cross-section off nucleons, a circumstance that makes the proposed search complementary to the existing ones. We discuss the prospects for detection with upcoming underwater and under-ice experiments such as ANTARES and IceCube, and show that several, up to many, sources could be detected with both experiments. A kilometer-scale telescope in the Mediterranean appears to be ideally suited for the proposed search.

  11. Neutrino mean free paths in cold symmetric nuclear matter

    SciTech Connect

    Cowell, S.; Pandharipande, V.R.

    2004-09-01

    The neutrino mean free paths (NMFP) for scattering and absorption in cold symmetric nuclear matter (SNM) are calculated using two-body effective interactions and one-body effective weak operators obtained from realistic models of nuclear forces using correlated basis theory. The infinite system is modeled in a box with periodic boundary conditions and the one particle-hole (p-h) response functions are calculated using the Tamm-Dancoff approximation (TDA). For the densities {rho}=(1/2), 1 (3/2){rho}{sub 0}, where {rho}{sub 0} is the equilibrium density of SNM, the strength of the response is shifted to higher energy transfers when compared to a noninteracting Fermi gas (FG). This and the weakness of effective operators compared to the bare operators, significantly reduces the cross sections, enhancing the NMFP by factors of {approx}2.5-3.5 at the densities considered. The NMFP at the equilibrium density {rho}{sub 0} are also calculated using the TDA and random phase approximation (RPA) using zero range Skyrme-like effective interactions with parameters chosen to reproduce the equation of state and spin-isospin susceptibilities of matter. Their results indicate that RPA corrections to correlated TDA may further increase the NMFP by {approx}25% to 3-4 times those in a noninteracting FG. Finally, the sums and the energy weighted sums of the Fermi and Gamow-Teller responses obtained from the correlated ground state are compared with those of the 1 p-h response functions to extract the sum and mean energies of multi p-h contributions to the weak response. The relatively large mean energy of the multi p-h excitations suggests that they may not contribute significantly to low energy NMFP.

  12. Effective field theory treatment of the neutrino background in direct dark matter detection experiments

    NASA Astrophysics Data System (ADS)

    Dent, James B.; Dutta, Bhaskar; Newstead, Jayden L.; Strigari, Louis E.

    2016-04-01

    Distinguishing a dark matter interaction from an astrophysical neutrino-induced interaction will be major challenge for future direct dark matter searches. In this paper, we consider this issue within nonrelativistic effective field theory (EFT), which provides a well-motivated theoretical framework for determining nuclear responses to dark matter scattering events. We analyze the nuclear energy recoil spectra from the different dark matter-nucleon EFT operators, and compare them to the nuclear recoil energy spectra that are predicted to be induced by astrophysical neutrino sources. We determine that for 11 of the 14 possible operators, the dark matter-induced recoil spectra can be cleanly distinguished from the corresponding neutrino-induced recoil spectra with moderate-size detector technologies that are now being pursued, e.g., these operators would require 0.5 tonne years to be distinguished from the neutrino background for low mass dark matter. Our results imply that in most models detectors with good energy resolution will be able to distinguish a dark matter signal from a neutrino signal, without the need for much larger detectors that must rely on additional information from timing or direction. In addition we calculate up-to-date exclusion limits in the EFT model space using data from the LUX experiment.

  13. Are collapse models testable with quantum oscillating systems? The case of neutrinos, kaons, chiral molecules

    NASA Astrophysics Data System (ADS)

    Bahrami, M.; Donadi, S.; Ferialdi, L.; Bassi, A.; Curceanu, C.; di Domenico, A.; Hiesmayr, B. C.

    2013-06-01

    Collapse models provide a theoretical framework for understanding how classical world emerges from quantum mechanics. Their dynamics preserves (practically) quantum linearity for microscopic systems, while it becomes strongly nonlinear when moving towards macroscopic scale. The conventional approach to test collapse models is to create spatial superpositions of mesoscopic systems and then examine the loss of interference, while environmental noises are engineered carefully. Here we investigate a different approach: We study systems that naturally oscillate-creating quantum superpositions-and thus represent a natural case-study for testing quantum linearity: neutrinos, neutral mesons, and chiral molecules. We will show how spontaneous collapses affect their oscillatory behavior, and will compare them with environmental decoherence effects. We will show that, contrary to what previously predicted, collapse models cannot be tested with neutrinos. The effect is stronger for neutral mesons, but still beyond experimental reach. Instead, chiral molecules can offer promising candidates for testing collapse models.

  14. Are collapse models testable with quantum oscillating systems? The case of neutrinos, kaons, chiral molecules.

    PubMed

    Bahrami, M; Donadi, S; Ferialdi, L; Bassi, A; Curceanu, C; Di Domenico, A; Hiesmayr, B C

    2013-01-01

    Collapse models provide a theoretical framework for understanding how classical world emerges from quantum mechanics. Their dynamics preserves (practically) quantum linearity for microscopic systems, while it becomes strongly nonlinear when moving towards macroscopic scale. The conventional approach to test collapse models is to create spatial superpositions of mesoscopic systems and then examine the loss of interference, while environmental noises are engineered carefully. Here we investigate a different approach: We study systems that naturally oscillate-creating quantum superpositions-and thus represent a natural case-study for testing quantum linearity: neutrinos, neutral mesons, and chiral molecules. We will show how spontaneous collapses affect their oscillatory behavior, and will compare them with environmental decoherence effects. We will show that, contrary to what previously predicted, collapse models cannot be tested with neutrinos. The effect is stronger for neutral mesons, but still beyond experimental reach. Instead, chiral molecules can offer promising candidates for testing collapse models. PMID:23739609

  15. Neutrino

    NASA Astrophysics Data System (ADS)

    Han, Yongquan

    2015-04-01

    The most basic Quantum are the particles who mutual rotation, quantum is composed of basic quantum.Quantum convergence or divergence is conditional, the faster the particle rotates, the smaller the orbiting radius will be, the greater quality is, the more density will be. The orbiting radius of less than 10-15 meters in the order of convergence, convergence of neutron, proton, and then they are in the formation of the nucleus, and the convergence of quantum can make extra nuclear electron and the formation of atomic; if rotation radius is more than 10-15 meters of magnitude, the internal quantum atoms diverge to outer space in the form of electromagnetic waves. The quality of magnetic wave particle is composed of the rotation speed of the particle which is internal of the electromagnetic, it doesn't matter about the electromagnetic wave propagation velocity of particles. Neutrinos are orbiting particles, the orbiting radius is about 10-15 meters, is a special kind of radiation. Neutrino is between the virtual particles (according to modern science, the electromagnetic wave doesn't have quality) and modern scientific (the particle who has quality) special particles

  16. Measurement of neutrino and antineutrino oscillations using beam and atmospheric data in MINOS.

    PubMed

    Adamson, P; Anghel, I; Backhouse, C; Barr, G; Bishai, M; Blake, A; Bock, G J; Bogert, D; Cao, S V; Castromonte, C M; Childress, S; Coelho, J A B; Corwin, L; Cronin-Hennessy, D; de Jong, J K; Devan, A V; Devenish, N E; Diwan, M V; Escobar, C O; Evans, J J; Falk, E; Feldman, G J; Frohne, M V; Gallagher, H R; Gomes, R A; Goodman, M C; Gouffon, P; Graf, N; Gran, R; Grzelak, K; Habig, A; Hahn, S R; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Hylen, J; Irwin, G M; Isvan, Z; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kordosky, M; Kreymer, A; Lang, K; Ling, J; Litchfield, P J; Lucas, P; Mann, W A; Marshak, M L; Mathis, M; Mayer, N; McGowan, A M; Medeiros, M M; Mehdiyev, R; Meier, J R; Messier, M D; Michael, D G; Miller, W H; Mishra, S R; Moed Sher, S; Moore, C D; Mualem, L; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nowak, J A; O'Connor, J; Oliver, W P; Orchanian, M; Pahlka, R B; Paley, J; Patterson, R B; Pawloski, G; Phan-Budd, S; Plunkett, R K; Qiu, X; Radovic, A; Rebel, B; Rosenfeld, C; Rubin, H A; Sanchez, M C; Schneps, J; Schreckenberger, A; Schreiner, P; Sharma, R; Sousa, A; Tagg, N; Talaga, R L; Thomas, J; Thomson, M A; Tinti, G; Tognini, S C; Toner, R; Torretta, D; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Weber, A; Webb, R C; White, C; Whitehead, L; Whitehead, L H; Wojcicki, S G; Zwaska, R

    2013-06-21

    We report measurements of oscillation parameters from ν(μ) and ν(μ) disappearance using beam and atmospheric data from MINOS. The data comprise exposures of 10.71×10(20) protons on target in the ν(μ)-dominated beam, 3.36×10(20) protons on target in the ν(μ)-enhanced beam, and 37.88 kton yr of atmospheric neutrinos. Assuming identical ν and ν oscillation parameters, we measure |Δm2| = (2.41(-0.10)(+0.09))×10(-3)  eV2 and sin2(2θ) = 0.950(-0.036)(+0.035). Allowing independent ν and ν oscillations, we measure antineutrino parameters of |Δm2| = (2.50(-0.25)(+0.23))×10(-3)  eV2 and sin2(2θ) = 0.97(-0.08)(+0.03), with minimal change to the neutrino parameters. PMID:23829728

  17. Gamma-ray and Neutrino Fluxes from Heavy Dark Matter in the Galactic Center

    NASA Astrophysics Data System (ADS)

    Gammaldi, V.; Cembranos, J. A. R.; de la Cruz-Dombriz, A.; Lineros, R. A.; Maroto, A. L.

    We present a study of the Galactic Center region as a possible source of both secondary gamma-ray and neutrino fluxes from annihilating dark matter. We have studied the gamma-ray flux observed by the High Energy Stereoscopic System (HESS) from the J1745-290 Galactic Center source. The data are well fitted as annihilating dark matter in combination with an astrophysical background. The analysis was performed by means of simulated gamma spectra produced by Monte Carlo event generators packages. We analyze the differences in the spectra obtained by the various Monte Carlo codes developed so far in particle physics. We show that, within some uncertainty, the HESS data can be fitted as a signal from a heavy dark matter density distribution peaked at the Galactic Center, with a power-law for the background with a spectral index which is compatible with the Fermi-Large Area Telescope (LAT) data from the same region. If this kind of dark matter distribution generates the gamma-ray flux observed by HESS, we also expect to observe a neutrino flux. We show prospective results for the observation of secondary neutrinos with the Astronomy with a Neutrino Telescope and Abyss environmental RESearch project (ANTARES), Ice Cube Neutrino Observatory (Ice Cube) and the Cubic Kilometer Neutrino Telescope (KM3NeT). Prospects solely depend on the device resolution angle when its effective area and the minimum energy threshold are fixed.

  18. Neutrino mass, proton decay, and neutron oscillations as crucial tests of unification models (A Review)

    PubMed Central

    Marshak, R. E.

    1982-01-01

    Several crucial tests of three popular unification models (of strong, electromagnetic, and weak interactions) are described. The models are SU(5) and SO(10) at the grand unification theory (GUT) level and SU(4)C × SU(2)L × SU(2)R at the partial unification theory (PUT) level. The tests selected for discussion are the finiteness of the neutrino mass in the electron volt region, the decay of protons into antileptons in the range of 1031± yr, and the detectability of neutron oscillations at all. The PUT group can also be tested by establishing the existence of four generations of quarks and leptons.

  19. Resurrecting hot dark matter - Large-scale structure from cosmic strings and massive neutrinos

    NASA Technical Reports Server (NTRS)

    Scherrer, Robert J.

    1988-01-01

    These are the results of a numerical simulation of the formation of large-scale structure from cosmic-string loops in a universe dominated by massive neutrinos (hot dark matter). This model has several desirable features. The final matter distribution contains isolated density peaks embedded in a smooth background, producing a natural bias in the distribution of luminous matter. Because baryons can accrete onto the cosmic strings before the neutrinos, the galaxies will have baryon cores and dark neutrino halos. Galaxy formation in this model begins much earlier than in random-phase models. On large scales the distribution of clustered matter visually resembles the CfA survey, with large voids and filaments.

  20. Non-thermal production of minimal dark matter via right-handed neutrino decay

    SciTech Connect

    Aoki, Mayumi; Toma, Takashi; Vicente, Avelino

    2015-09-29

    Minimal Dark Matter (MDM) stands as one of the simplest dark matter scenarios. In MDM models, annihilation and co-annihilation processes among the members of the MDM multiplet are usually very efficient, pushing the dark matter mass above O(10) TeV in order to reproduce the observed dark matter relic density. Motivated by this little drawback, in this paper we consider an extension of the MDM scenario by three right-handed neutrinos. Two specific choices for the MDM multiplet are studied: a fermionic SU(2){sub L} quintuplet and a scalar SU(2){sub L} septuplet. The lightest right-handed neutrino, with tiny Yukawa couplings, never reaches thermal equilibrium in the early universe and is produced by freeze-in. This creates a link between dark matter and neutrino physics: dark matter can be non-thermally produced by the decay of the lightest right-handed neutrino after freeze-out, allowing to lower significantly the dark matter mass. We discuss the phenomenology of the non-thermally produced MDM and, taking into account significant Sommerfeld corrections, we find that the dark matter mass must have some specific values in order not to be in conflict with the current bounds from gamma-ray observations.

  1. Non-thermal production of minimal dark matter via right-handed neutrino decay

    NASA Astrophysics Data System (ADS)

    Aoki, Mayumi; Toma, Takashi; Vicente, Avelino

    2015-09-01

    Minimal Dark Matter (MDM) stands as one of the simplest dark matter scenarios. In MDM models, annihilation and co-annihilation processes among the members of the MDM multiplet are usually very efficient, pushing the dark matter mass above Script O(10) TeV in order to reproduce the observed dark matter relic density. Motivated by this little drawback, in this paper we consider an extension of the MDM scenario by three right-handed neutrinos. Two specific choices for the MDM multiplet are studied: a fermionic SU(2)L quintuplet and a scalar SU(2)L septuplet. The lightest right-handed neutrino, with tiny Yukawa couplings, never reaches thermal equilibrium in the early universe and is produced by freeze-in. This creates a link between dark matter and neutrino physics: dark matter can be non-thermally produced by the decay of the lightest right-handed neutrino after freeze-out, allowing to lower significantly the dark matter mass. We discuss the phenomenology of the non-thermally produced MDM and, taking into account significant Sommerfeld corrections, we find that the dark matter mass must have some specific values in order not to be in conflict with the current bounds from gamma-ray observations.

  2. Low Energy Neutrino and Dark Matter Physics with sub-keV Germanium Detectors

    SciTech Connect

    Singh, L.; Singh, V.; Soma, A. K.; Singh, M. K.; Wong, H. T.

    2011-10-06

    A TEXONO collaboration research program on low energy neutrino and dark matter physics is going on at the Kuo-Sheng Neutrino Laboratory (KSNL). Collaboration main goals are to measure the neutrino-nucleus coherent scattering cross section, neutrino magnetic moments, and the searches of WIMP dark matter. To achieve these goals various prototype detectors and their sub-keV background are under study. A threshold of 220 eV was achieved with prototype detectors at the KSNL. New limits were set for WIMPs with mass between 3-6 GeV. Data are being taken with a 500 g Point Contact Germanium detector, where a threshold of {approx}350 eV was demonstrated. A 20 g ULEGe detector is taking data at CJPL in Sichuan, China.

  3. Readout strategies for directional dark matter detection beyond the neutrino background

    NASA Astrophysics Data System (ADS)

    O'Hare, Ciaran A. J.; Green, Anne M.; Billard, Julien; Figueroa-Feliciano, Enectali; Strigari, Louis E.

    2015-09-01

    The search for weakly interacting massive particles (WIMPs) by direct detection faces an encroaching background due to coherent neutrino-nucleus scattering. As the sensitivity of these experiments improves, the question of how to best distinguish a dark matter signal from neutrinos will become increasingly important. A proposed method of overcoming this so-called "neutrino floor" is to utilize the directional signature that both neutrino- and dark-matter-induced recoils possess. We show that directional experiments can indeed probe WIMP-nucleon cross sections below the neutrino floor with little loss in sensitivity due to the neutrino background. In particular we find at low WIMP masses (around 6 GeV) the discovery limits for directional detectors penetrate below the nondirectional limit by several orders of magnitude. For high WIMP masses (around 100 GeV), the nondirectional limit is overcome by a factor of a few. Furthermore we show that even for directional detectors which can only measure one- or two-dimensional projections of the three-dimensional recoil track, the discovery potential is only reduced by a factor of 3 at most. We also demonstrate that while the experimental limitations of directional detectors, such as sense recognition and finite angular resolution, have a detrimental effect on the discovery limits, it is still possible to overcome the ultimate neutrino background faced by nondirectional detectors.

  4. Dynamical framework for KeV Dirac neutrino warm dark matter

    NASA Astrophysics Data System (ADS)

    Robinson, Dean J.; Tsai, Yuhsin

    2014-08-01

    If the source of the reported 3.5 keV x-ray line is a sterile neutrino, comprising an O(1) fraction of the dark matter (DM), then it exhibits the property that its mass times mixing angle is ˜ few×10-2 eV, a plausible mass scale for the active neutrinos. This property is a common feature of Dirac neutrino mixing. We present a framework that dynamically produces light active and keV sterile Dirac neutrinos, with appropriate mixing angles to be the x-ray line source. The central idea is that the right-handed active neutrino is a composite state, while elementary sterile neutrinos gain keV masses similarly to the quarks in extended technicolor. The entire framework is fixed by just two dynamical scales and may automatically exhibit a warm dark matter (WDM) production mechanism—dilution of thermal relics from late decays of a heavy composite neutrino—such that the keV neutrinos may comprise an O(1) fraction of the DM. In this framework, the WDM is typically quite cool and within structure formation bounds, with temperature ˜ few×10-2Tν and free-streaming length ˜ few kpc. A toy model that exhibits the central features of the framework is also presented.

  5. Testing the Big Bang: Light elements, neutrinos, dark matter and large-scale structure

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1991-01-01

    Several experimental and observational tests of the standard cosmological model are examined. In particular, a detailed discussion is presented regarding: (1) nucleosynthesis, the light element abundances, and neutrino counting; (2) the dark matter problems; and (3) the formation of galaxies and large-scale structure. Comments are made on the possible implications of the recent solar neutrino experimental results for cosmology. An appendix briefly discusses the 17 keV thing and the cosmological and astrophysical constraints on it.

  6. Accounting for the Unresolved X-ray Background with Sterile Neutrino Dark Matter

    SciTech Connect

    Cumberbatch, D.T.; Silk, Joseph

    2007-11-20

    We consider a scenario where keV sterile neutrinos constitute all of the currently inferred dark matter abundance, whose radiative decays could potentially account for the flux contributions to the X-ray background (XRB) by unresolved sources. Here we apply integrated flux methods to results from the observations of the North/South Chandra deep fields (CDF-N/S) in order to deduce constraints on the sterile neutrino mass-mixing parameters.

  7. New U(1) gauge model of radiative lepton masses with sterile neutrino and dark matter

    NASA Astrophysics Data System (ADS)

    Adhikari, Rathin; Borah, Debasish; Ma, Ernest

    2016-04-01

    An anomaly-free U(1) gauge extension of the standard model (SM) is presented. Only one Higgs doublet with a nonzero vacuum expectation is required as in the SM. New fermions and scalars as well as all SM particles transform nontrivially under this U(1), resulting in a model of three active neutrinos and one sterile neutrino, all acquiring radiative masses. Charged-lepton masses are also radiative as well as the mixing between active and sterile neutrinos. At the same time, a residual Z2 symmetry of the U(1) gauge symmetry remains exact, allowing for the existence of dark matter.

  8. Effect of the 2 p 2 h cross-section uncertainties on an analysis of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Ankowski, Artur M.; Benhar, Omar; Mariani, Camillo; Vagnoni, Erica

    2016-06-01

    We report the results of a study aimed at quantifying the impact on the oscillation analysis of the uncertainties associated with the description of the neutrino-nucleus cross section in the two-particle-two-hole sector. The results of our calculations, based on the kinematic method of energy reconstruction and carried out comparing two data-driven approaches, show that the existing discrepancies in the neutrino cross sections have a sizable effect on the extracted oscillation parameters, particularly in the antineutrino channel.

  9. Supernova neutrinos and explosive nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

    2014-05-01

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes 7Li, 11B, 92Nb, 138La and 180Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ13, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements 11B and 7Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ13, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  10. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  11. Higher order corrections to the large scale matter power spectrum in the presence of massive neutrinos

    SciTech Connect

    Wong, Yvonne Y Y

    2008-10-15

    We present the first systematic derivation of the one-loop correction to the large scale matter power spectrum in a mixed cold + hot dark matter cosmology with subdominant massive neutrino hot dark matter. Starting with the equations of motion for the density and velocity fields, we derive perturbative solutions to these quantities and construct recursion relations for the interaction kernels, noting and justifying all approximations along the way. We find interaction kernels similar to those for a cold dark matter only universe, but with additional dependences on the neutrino energy density fraction f{sub {nu}} and the linear growth functions of the incoming wavevectors. Compared with the f{sub {nu}} = 0 case, the one-loop corrected matter power spectrum for a mixed dark matter cosmology exhibits a decrease in small scale power exceeding the canonical {approx}8f{sub {nu}} suppression predicted by linear theory, a feature also seen in multi-component N-body simulations.

  12. Probing the stability of superheavy dark matter particles with high-energy neutrinos

    SciTech Connect

    Esmaili, Arman; Peres, Orlando L.G.; Ibarra, Alejandro E-mail: ibarra@tum.de

    2012-11-01

    Two of the most fundamental properties of the dark matter particle, the mass and the lifetime, are only weakly constrained by the astronomical and cosmological evidence of dark matter. We derive in this paper lower limits on the lifetime of dark matter particles with masses in the range 10TeV−10{sup 15}TeV from the non-observation of ultrahigh energy neutrinos in the AMANDA, IceCube, Auger and ANITA experiments. For dark matter particles which produce neutrinos in a two body or a three body leptonic decay, we find that the dark matter lifetime must be longer than O(10{sup 26}−10{sup 28})s for masses between 10 TeV and the Grand Unification scale. Finally, we also calculate, for concrete particle physics scenarios, the limits on the strength of the interactions that induce the dark matter decay.

  13. Neutrino physics with JUNO

    NASA Astrophysics Data System (ADS)

    An, Fengpeng; An, Guangpeng; An, Qi; Antonelli, Vito; Baussan, Eric; Beacom, John; Bezrukov, Leonid; Blyth, Simon; Brugnera, Riccardo; Buizza Avanzini, Margherita; Busto, Jose; Cabrera, Anatael; Cai, Hao; Cai, Xiao; Cammi, Antonio; Cao, Guofu; Cao, Jun; Chang, Yun; Chen, Shaomin; Chen, Shenjian; Chen, Yixue; Chiesa, Davide; Clemenza, Massimiliano; Clerbaux, Barbara; Conrad, Janet; D'Angelo, Davide; De Kerret, Hervé; Deng, Zhi; Deng, Ziyan; Ding, Yayun; Djurcic, Zelimir; Dornic, Damien; Dracos, Marcos; Drapier, Olivier; Dusini, Stefano; Dye, Stephen; Enqvist, Timo; Fan, Donghua; Fang, Jian; Favart, Laurent; Ford, Richard; Göger-Neff, Marianne; Gan, Haonan; Garfagnini, Alberto; Giammarchi, Marco; Gonchar, Maxim; Gong, Guanghua; Gong, Hui; Gonin, Michel; Grassi, Marco; Grewing, Christian; Guan, Mengyun; Guarino, Vic; Guo, Gang; Guo, Wanlei; Guo, Xin-Heng; Hagner, Caren; Han, Ran; He, Miao; Heng, Yuekun; Hsiung, Yee; Hu, Jun; Hu, Shouyang; Hu, Tao; Huang, Hanxiong; Huang, Xingtao; Huo, Lei; Ioannisian, Ara; Jeitler, Manfred; Ji, Xiangdong; Jiang, Xiaoshan; Jollet, Cécile; Kang, Li; Karagounis, Michael; Kazarian, Narine; Krumshteyn, Zinovy; Kruth, Andre; Kuusiniemi, Pasi; Lachenmaier, Tobias; Leitner, Rupert; Li, Chao; Li, Jiaxing; Li, Weidong; Li, Weiguo; Li, Xiaomei; Li, Xiaonan; Li, Yi; Li, Yufeng; Li, Zhi-Bing; Liang, Hao; Lin, Guey-Lin; Lin, Tao; Lin, Yen-Hsun; Ling, Jiajie; Lippi, Ivano; Liu, Dawei; Liu, Hongbang; Liu, Hu; Liu, Jianglai; Liu, Jianli; Liu, Jinchang; Liu, Qian; Liu, Shubin; Liu, Shulin; Lombardi, Paolo; Long, Yongbing; Lu, Haoqi; Lu, Jiashu; Lu, Jingbin; Lu, Junguang; Lubsandorzhiev, Bayarto; Ludhova, Livia; Luo, Shu; Lyashuk, Vladimir; Möllenberg, Randolph; Ma, Xubo; Mantovani, Fabio; Mao, Yajun; Mari, Stefano M.; McDonough, William F.; Meng, Guang; Meregaglia, Anselmo; Meroni, Emanuela; Mezzetto, Mauro; Miramonti, Lino; Mueller, Thomas; Naumov, Dmitry; Oberauer, Lothar; Ochoa-Ricoux, Juan Pedro; Olshevskiy, Alexander; Ortica, Fausto; Paoloni, Alessandro; Peng, Haiping; Peng, Jen-Chieh; Previtali, Ezio; Qi, Ming; Qian, Sen; Qian, Xin; Qian, Yongzhong; Qin, Zhonghua; Raffelt, Georg; Ranucci, Gioacchino; Ricci, Barbara; Robens, Markus; Romani, Aldo; Ruan, Xiangdong; Ruan, Xichao; Salamanna, Giuseppe; Shaevitz, Mike; Sinev, Valery; Sirignano, Chiara; Sisti, Monica; Smirnov, Oleg; Soiron, Michael; Stahl, Achim; Stanco, Luca; Steinmann, Jochen; Sun, Xilei; Sun, Yongjie; Taichenachev, Dmitriy; Tang, Jian; Tkachev, Igor; Trzaska, Wladyslaw; van Waasen, Stefan; Volpe, Cristina; Vorobel, Vit; Votano, Lucia; Wang, Chung-Hsiang; Wang, Guoli; Wang, Hao; Wang, Meng; Wang, Ruiguang; Wang, Siguang; Wang, Wei; Wang, Yi; Wang, Yi; Wang, Yifang; Wang, Zhe; Wang, Zheng; Wang, Zhigang; Wang, Zhimin; Wei, Wei; Wen, Liangjian; Wiebusch, Christopher; Wonsak, Björn; Wu, Qun; Wulz, Claudia-Elisabeth; Wurm, Michael; Xi, Yufei; Xia, Dongmei; Xie, Yuguang; Xing, Zhi-zhong; Xu, Jilei; Yan, Baojun; Yang, Changgen; Yang, Chaowen; Yang, Guang; Yang, Lei; Yang, Yifan; Yao, Yu; Yegin, Ugur; Yermia, Frédéric; You, Zhengyun; Yu, Boxiang; Yu, Chunxu; Yu, Zeyuan; Zavatarelli, Sandra; Zhan, Liang; Zhang, Chao; Zhang, Hong-Hao; Zhang, Jiawen; Zhang, Jingbo; Zhang, Qingmin; Zhang, Yu-Mei; Zhang, Zhenyu; Zhao, Zhenghua; Zheng, Yangheng; Zhong, Weili; Zhou, Guorong; Zhou, Jing; Zhou, Li; Zhou, Rong; Zhou, Shun; Zhou, Wenxiong; Zhou, Xiang; Zhou, Yeling; Zhou, Yufeng; Zou, Jiaheng

    2016-03-01

    . Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ˜400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the {θ }23 mixing angle. Detection of the 7Be and 8B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with {10}-5 {{{eV}}}2\\lt {{Δ }}{m}412\\lt {10}-2 {{{eV}}}2 and a sufficiently large mixing angle {θ }14 could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the p\\to {K}++\\bar{ν } decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one

  14. PREFACE: Nobel Symposium 129 on Neutrino Physics

    NASA Astrophysics Data System (ADS)

    Bergström, Lars; Botner, Olga; Carlson, Per; Hulth, Per Olof; Ohlsson, Tommy

    2005-01-01

    Nobel Symposium 129 on Neutrino Physics was held at Haga Slott in Enköping, Sweden during August 19 24, 2004. Invited to the symposium were around 40 globally leading researchers in the field of neutrino physics, both experimental and theoretical. In addition to these participants, some 30 local researchers and graduate students participated in the symposium. The dominant theme of the lectures was neutrino oscillations, which after several years were recently verified by results from the Super-Kamiokande detector in Kamioka, Japan and the SNO detector in Sudbury, Canada. Discussion focused especially on effects of neutrino oscillations derived from the presence of matter and the fact that three different neutrinos exist. Since neutrino oscillations imply that neutrinos have mass, this is the first experimental observation that fundamentally deviates from the standard model of particle physics. This is a challenge to both theoretical and experimental physics. The various oscillation parameters will be determined with increased precision in new, specially designed experiments. Theoretical physics is working intensively to insert the knowledge that neutrinos have mass into the theoretical models that describe particle physics. It will probably turn out that the discovery of neutrino oscillations signifies a breakthrough in the description of the very smallest constituents of matter. The lectures provided a very good description of the intensive situation in the field right now. The topics discussed also included mass models for neutrinos, neutrinos in extra dimensions as well as the `seesaw mechanism', which provides a good description of why neutrino masses are so small. Also discussed, besides neutrino oscillations, was the new field of neutrino astronomy. Among the questions that neutrino astronomy hopes to answer are what the dark matter in the Universe consists of and where cosmic radiation at extremely high energies comes from. For this purpose, large neutrino

  15. Neutrinos

    PubMed Central

    Besson, Dave; Cowen, Doug; Selen, Mats; Wiebusch, Christopher

    1999-01-01

    Neutrinos represent a new “window” to the Universe, spanning a large range of energy. We discuss the science of neutrino astrophysics and focus on two energy regimes. At “lower” energies (≈1 MeV), studies of neutrinos born inside the sun, or produced in interactions of cosmic rays with the atmosphere, have allowed the first incontrovertible evidence that neutrinos have mass. At energies typically one thousand to one million times higher, sources further than the sun (both within the Milky Way and beyond) are expected to produce a flux of particles that can be detected only through neutrinos. PMID:10588680

  16. Long-range forces: atmospheric neutrino oscillation at a magnetized detector

    SciTech Connect

    Samanta, Abhijit

    2011-09-01

    Among the combinations L{sub e}-L{sub μ}, L{sub e}-L{sub τ} and L{sub μ}-L{sub τ} any one can be gauged in anomaly free way with the standard model gauge group. The masses of these gauge bosons can be so light that it can induce long-range forces on the Earth due to the electrons in the Sun. This type of forces can be constrained significantly from neutrino oscillation. As the sign of the potential is opposite for neutrinos and antineutrinos, a magnetized iron calorimeter detector (ICAL) would be able to produce strong constraint on it. We have made conservative studies of these long-range forces with atmospheric neutrinos at ICAL considering only the muons of charge current interactions. We find stringent bounds on the couplings α{sub eμ,eτ} ∼< 1.65 × 10{sup −53} at 3σ CL with an exposure of 1 Mton·yr if there is no such force. For nonzero input values of the couplings we find that the potential V{sub eμ} opposes and V{sub eτ} helps to discriminate the mass hierarchy. However, both potentials help significantly to discriminate the octant of θ{sub 23}. The explanation of the anomaly in recent MINOS data (the difference of Δm{sub 32}{sup 2} for neutrinos and antineutrinos), using long-range force originated from the mixing of the gauge boson Z' of L{sub μ}-L{sub τ} with the standard model gauge boson Z, can be tested at ICAL at more than 5σ CL. We have also discussed how to disentangle this from the solution with CPT violation using the seasonal change of the distance between the Earth and the Sun.

  17. Coherent neutrino interactions in a dense medium

    NASA Astrophysics Data System (ADS)

    Kiers, Ken; Weiss, Nathan

    1997-11-01

    Motivated by the effect of matter on neutrino oscillations (the MSW effect) we study in more detail the propagation of neutrinos in a dense medium. The dispersion relation for massive neutrinos in a medium is known to have a minimum at nonzero momentum p~GFρ/2. We study in detail the origin and consequences of this dispersion relation for both Dirac and Majorana neutrinos both in a toy model with only neutral currents and a single neutrino flavor and in a realistic ``standard model'' with two neutrino flavors. We find that for a range of neutrino momenta near the minimum of the dispersion relation, Dirac neutrinos are trapped by their coherent interactions with the medium. This effect does not lead to the trapping of Majorana neutrinos.

  18. Toward a full test of the ν MSM sterile neutrino dark matter model with Athena

    NASA Astrophysics Data System (ADS)

    Neronov, A.; Malyshev, D.

    2016-03-01

    We discuss the potential of Athena x-ray telescope, in particular of its x-ray integral field unit (X-IFU), for detection of the signal from the light-weight decaying dark matter with mass in the keV range. We show that high energy resolution and large collection area of X-IFU will provide an improvement of sensitivity which will be sufficient for the full test of the neutrino minimal extension of the standard model (ν MSM ). Search for the narrow spectral line produced by the decay of the dark matter sterile neutrino in the spectra of dwarf spheroidal galaxies with X-IFU will explore the whole allowed range masses and mixing angles of the ν MSM lightest sterile neutrino and in this way either to find the dark matter signal or rule out the ν MSM model.

  19. Searching for dark matter annihilation to monoenergetic neutrinos with liquid scintillation detectors

    SciTech Connect

    Kumar, J.; Sandick, P.

    2015-06-22

    We consider searches for dark matter annihilation to monoenergetic neutrinos in the core of the Sun. We find that liquid scintillation neutrino detectors have enhanced sensitivity to this class of dark matter models, due to the energy and angular resolution possible for electron neutrinos and antineutrinos that scatter via charged-current interactions. In particular we find that KamLAND, utilizing existing data, could provide better sensitivity to such models than any current direct detection experiment for m{sub X}≲15 Gev. KamLAND’s sensitivity is signal-limited, and future liquid scintillation or liquid argon detectors with similar energy and angular resolution, but with larger exposure, will provide significantly better sensitivity. These detectors may be particularly powerful probes of dark matter with mass O(10) GeV.

  20. Dark matter searches for monoenergetic neutrinos arising from stopped meson decay in the Sun

    SciTech Connect

    Rott, Carsten; In, Seongjin; Kumar, Jason; Yaylali, David

    2015-11-24

    Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark matter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub-GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scintillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.

  1. Dark matter searches for monoenergetic neutrinos arising from stopped meson decay in the Sun

    NASA Astrophysics Data System (ADS)

    Rott, Carsten; In, Seongjin; Kumar, Jason; Yaylali, David

    2015-11-01

    Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark matter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub-GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scintillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.

  2. Solar neutrinos: Theoretical status

    NASA Astrophysics Data System (ADS)

    Haxton, W. C.

    I review the standard solar model, the disparities between its predictions and the solar neutrino flux measurements of the Homestake and Kamioka 2 collaborations, and possible particle physics resolutions of this puzzle. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained by building analogies with more familiar atomic physics phenomena. These and other mechanisms are considered as possible explanations for time variations in the solar neutrino flux. Finally, I consider possible outcomes and implications of the SAGE/GALLEX gallium experiments.

  3. Dark matter annihilation into right-handed neutrinos and the galactic center gamma-ray excess

    NASA Astrophysics Data System (ADS)

    Tang, Yi-Lei; Zhu, Shou-hua

    2016-03-01

    In this paper, we will discuss a specific case that the dark matter particles annihilate into right-handed neutrinos. We calculate the predicted gamma-ray excess from the galactic center and compare our results with the data from the Fermi-LAT. An approximately 10-60 GeV right-handed neutrino with heavier dark matter particle can perfectly explain the observed spectrum. The annihilation cross section <σ v> falls within the range 0 .5-4 × 10-26 cm3 /s, which is roughly compatible with the WIMP annihilation cross section.

  4. Resonant oscillations of GeV-TeV neutrinos in internal shocks from gamma-ray burst jets inside stars

    NASA Astrophysics Data System (ADS)

    Fraija, Nissim

    2015-07-01

    High-energy neutrinos generated in collimated jets inside the progenitors of gamma-ray bursts (GRBs) have been related to the events detected by IceCube. These neutrinos, produced by hadronic interactions of Fermi-accelerated protons with thermal photons and hadrons in internal shocks, are the only signature when the jet has not broken out or failed. Taking into account that the photon field is thermalized at keV energies and the standard assumption that the magnetic field maintains a steady value throughout the shock region (with a width of 1010-1011 cm in the observed frame), we study the effect of thermal and magnetized plasma generated in internal shocks on the neutrino oscillations. We calculate the neutrino effective potential generated by this plasma, the effects of the envelope of the star, and the vacuum on the path to Earth. By considering these three effects, the two (solar, atmospheric and accelerator parameters) and three neutrino mixing, we show that although GeV-TeV neutrinos can oscillate resonantly from one flavour to another, a non-significant deviation of the standard flavour ratio (1: 1: 1) could be expected on Earth.

  5. Constraints on sterile neutrino dark matter production in the light of Planck

    NASA Astrophysics Data System (ADS)

    Popa, Lucia Aurelia

    Distortions of CMB temperature and polarization anisotropy maps caused by gravitational lensing, observable with high angular resolution and sensitivity of the Planck mission are used to constrain the Dark Matter (DM) sterile neutrino mass. This analysis offers several advantages against the analysis based on the combination of CMB, LSS and Ly-alpha forest power spectra. As the gravitational lensing effect depends on the matter distribution, no assumption on light-to-mass bias is required. In addition, unlike the galaxy clustering and Ly-alpha forest power spectra, the projected gravitational potential power spectrum probes a larger range of angular scales, the non-linear corrections being required only at very small scales. Taking into account the changes in the time-temperature relation of the primordial plasma and the modification of the neutrino thermal potential, we compute the projected gravitational potential power spectrum and its correlation with the temperature in the presence of DM sterile neutrino. We show that the cosmological parameters are generally not biased when DM sterile neutrino is included. From this analysis we placed lower limits on DM sterile neutrino for both resonant and non-resonant production. We conclude that although the information that can be obtained from lensing extraction is rather limited due to the high level of the lensing noise of Planck experiment, weak lensing of CMB offers a valuable alternative to constrain the DM sterile neutrino mass.

  6. Recent results from the ANTARES deep sea neutrino telescope

    NASA Astrophysics Data System (ADS)

    Coyle, Paschal

    2013-02-01

    The ANTARES deep sea neutrino telescope has acquired over four years of high quality data. This data has been used to measure the oscillation parameters of atmospheric neutrinos and also to search for neutrinos of a nonterrestrial origin. Competitive upper limits on the fluxes of neutrinos from dark matter annihilation in the Sun, a variety of Galactic and extra-galactic sources, both steady and transient, are presented.

  7. Small scale aspects of warm dark matter: Power spectra and acoustic oscillations

    SciTech Connect

    Boyanovsky, Daniel; Wu Jun

    2011-02-15

    We provide a semianalytic derivation of approximate evolution equations for density perturbations of warm dark matter candidates that decoupled while relativistic with arbitrary distribution functions, their solutions at small scales, and a simple numerical implementation that yields their transfer functions and power spectra. Density perturbations evolve through three stages: radiation domination when the particle is relativistic and nonrelativistic and matter domination. An early integrated Sachs-Wolfe effect during the first stage leads to an enhancement of density perturbations and a plateau in the transfer function for k < or approx. k{sub fs}, the free-streaming wave vector. An effective fluid description emerges at small scales which includes the effects of free streaming in initial conditions and inhomogeneities. The transfer function features warm dark matter acoustic oscillations at scales k > or approx. 2k{sub fs}. A simple analytic interpolation of the power spectra between large and small scales and a numerical implementation valid for arbitrary distribution functions is provided. As an application we study the power spectra for two models of sterile neutrinos with m{approx}keV produced nonresonantly and compare our results to those obtained from Boltzmann codes.

  8. Subdominant Dark Matter sterile neutrino resonant production in the light of PLANCK

    NASA Astrophysics Data System (ADS)

    Popa, L. A.; Tonoiu, D.

    2015-09-01

    Few independent detections of a weak X-ray line at an energy of ~ 3.5 keV seen toward a number of astrophysical sites have been reported. If this signal will be confirmed to be the signature of decaying DM sterile neutrino with a mass of ~ 7.1 keV, then the cosmological observables should be consistent with its properties. In this paper we make a coupled treatment of the weak decoupling, primordial nucleosynthesis and photon decoupling epochs in the sterile neutrino resonant production scenario, including the extra radiation energy density via Neff. We compute the radiation and matter perturbations including the full resonance sweep solution for να/bar nuα → νs flavor conversion in the expanding Universe.We show that the cosmological measurements are in agreement with subdominant Dark Matter sterile neutrino resonant production with following parameters (errors at 95% CL): mass mνs=6.08 ± 3.22 keV, mixing angle sin2 2θ < 5.61 × 10-10, lepton number per flavor L4 = 1.23 ± 0.04 (L4 ≡ 104 Lνa) and sterile neutrino mass fraction fνs< 0.078.Our results are in good agreement with the sterile neutrino resonant production parameters inferred in ref. [1] from the linear large scale structure constraints to produce full Dark Matter density.

  9. Solar and Terrestrial Neutrino Results from Borexino

    NASA Astrophysics Data System (ADS)

    Calaprice, Frank; Borexino Collaboration

    2012-08-01

    Borexino is a low background liquid scintillation detector currently acquiring solar and terrestrial neutrino data at the LNGS underground laboratory in Italy. In the three years since the start of operations in 2007, Borexino has produced measurements of 7Be and 8B solar neutrinos, as well as measurements of terrestrial and long-baseline reactor anti-neutrinos. The measurements of sub-MeV neutrinos were possible owing to a breakthrough in low background methods. Current results and prospects for future measurements with lower background and higher accuracy are discussed in the context of exploring the transition from vacuum to matter enhanced neutrino oscillations.

  10. Correction of dephasing oscillations in matter-wave interferometry

    NASA Astrophysics Data System (ADS)

    Rembold, A.; Schütz, G.; Chang, W. T.; Stefanov, A.; Pooch, A.; Hwang, I. S.; Günther, A.; Stibor, A.

    2014-03-01

    Vibrations, electromagnetic oscillations, and temperature drifts are among the main reasons for dephasing in matter-wave interferometry. Sophisticated interferometry experiments, e.g., with ions or heavy molecules, often require integration times of several minutes due to the low source intensity or the high velocity selection. Here we present a scheme to suppress the influence of such dephasing mechanisms—especially in the low-frequency regime—by analyzing temporal and spatial particle correlations available in modern detectors. Such correlations can reveal interference properties that would otherwise be washed out due to dephasing by external oscillating signals. The method is shown experimentally in a biprism electron interferometer where a perturbing oscillation is artificially introduced by a periodically varying magnetic field. We provide a full theoretical description of the particle correlations where the perturbing frequency and amplitude can be revealed from the disturbed interferogram. The original spatial fringe pattern without the perturbation can thereby be restored. The technique can be applied to lower the general noise requirements in matter-wave interferometers. It allows for the optimization of electromagnetic shielding and decreases the efforts for vibrational or temperature stabilization.

  11. Propagation and neutrino oscillations in the base of a highly magnetized gamma-ray burst fireball flow

    SciTech Connect

    Fraija, N.

    2014-06-01

    Neutrons play an important role in the dynamics of gamma-ray bursts. The presence of neutrons in the baryon-loaded fireball is expected. If the neutron abundance is comparable to that of protons, important features may be observed, such as quasi-thermal multi-GeV neutrinos in coincidence with a subphotospheric γ-ray emission, nucleosynthesis at later times, and rebrightening of the afterglow emission. Additionally, thermal MeV neutrinos are created by electron-positron annihilation, electron (positron) capture on protons (neutrons), and nucleonic bremsstrahlung. Although MeV neutrinos are difficult to detect, quasi-thermal GeV neutrinos are expected in cubic kilometer detectors and/or DeepCore and IceCube. In this paper, we show that neutrino oscillations have outstanding implications for the dynamics of the fireball evolution and also that they can be detected through their flavor ratio on Earth. For that, we derive the resonance and charged-neutrality conditions as well as the neutrino self-energy and effective potential up to the order of m{sub W}{sup −4} at strong, moderate, and weak magnetic field approximations to constrain the dynamics of the fireball. We found important implications: (1) resonant oscillations are suppressed for high baryon densities as well as neutron abundance larger than that of protons, and (2) the effect of magnetic field is to decrease the proton-to-neutron ratio aside from the number of multi-GeV neutrinos expected in the DeepCore detector. Also, we estimate the GeV neutrino flavor ratios along the jet and on Earth.

  12. Neutrino Physics and Dark Matter Physics with Ultra-Low-Energy Germanium Detector

    SciTech Connect

    Shin-Ted, Lin

    2008-10-10

    The status and plans of the TEXONO Collaboration on the development of ultra-low-energy germanium detectors with sub-keV sensitivities are reported. We survey the scientific goals which include the observation of neutrino-nucleus coherent scattering, the studies of neutrino magnetic moments, as well as the searches of WIMP dark matter. In particular, an energy threshold of 220{+-}10 eV at an efficiency of 50% were achieved with a four-channel prototype detectors each of an active mass of 5 g. New limits were set for WIMPs with mass between 3-6 GeV. The prospects of the realization of full-scale experiments are discussed. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.

  13. Dark Matter and neutrino masses from global U(1) B - L symmetry breaking

    NASA Astrophysics Data System (ADS)

    Lindner, Manfred; Schmidt, Daniel; Schwetz, Thomas

    2011-11-01

    We present a scenario where neutrino masses and Dark Matter are related due to a global U(1) B - L symmetry. Specifically we consider neutrino mass generation via the Zee-Babu two-loop mechanism, augmented by a scalar singlet whose VEV breaks the global U(1) B - L symmetry. In order to obtain a Dark Matter candidate we introduce two Standard Model singlet fermions. They form a Dirac particle and are stable because of a remnant Z2 symmetry. Hence, in this model the stability of Dark Matter follows from the global U(1) B - L symmetry. We discuss the Dark Matter phenomenology of the model, and compare it to similar models based on gauged U(1) B - L. We argue that in contrast to the gauged versions, the model based on the global symmetry does not suffer from severe constraints from Z‧ searches.

  14. Development of a scintillating fiber tracking detector for the K2K neutrino oscillation experiment

    SciTech Connect

    Suzuki, Atsumu

    1998-11-09

    We are preparing a scintillating fiber tracking detector as a part of the near fine-grained detector in the K2K long baseline neutrino oscillation experiment between KEK and Super-Kamiokande. We use Kuraray SCSF-78, 0.7 mm diameter fiber with Hamamatsu IIT-CCD camera read out system. The choice of the fiber is based on a series of measurements of the light yield and aging of the candidate fibers under various conditions. It was found that SCSF-78 has enough light yield and lifetime for our purposes. We have also checked the performance of the SCIFI sheet-IIT-CCD system by source ({sup 90}Sr) and cosmic rays. The detection efficiency was found to be more than 99%. The full SCIFI detector construction is current under way.

  15. Development of a scintillating fiber tracking detector for the K2K neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsumu

    1998-11-01

    We are preparing a scintillating fiber tracking detector as a part of the near fine-grained detector in the K2K long baseline neutrino oscillation experiment between KEK and Super-Kamiokande. We use Kuraray SCSF-78, 0.7 mm diameter fiber with Hamamatsu IIT-CCD camera read out system. The choice of the fiber is based on a series of measurements of the light yield and aging of the candidate fibers under various conditions. It was found that SCSF-78 has enough light yield and lifetime for our purposes. We have also checked the performance of the SCIFI sheet-IIT-CCD system by source (90Sr) and cosmic rays. The detection efficiency was found to be more than 99%. The full SCIFI detector construction is current under way.

  16. Neutrino mean free path in neutron matter with Brussels-Montreal Skyrme functionals

    NASA Astrophysics Data System (ADS)

    Pastore, A.; Martini, M.; Davesne, D.; Navarro, J.; Chamel, N.; Goriely, S.

    2016-01-01

    We calculate the neutrino mean free path in cold neutron matter with some modern Brussels-Montreal functionals. The three typical functionals used in this article produce quite different results implying a possible impact on the cooling mechanism of neutron stars.

  17. Dark matter, {mu} problem, and neutrino mass with gauged R symmetry

    SciTech Connect

    Choi, Ki-Young; Chun, Eung Jin; Lee, Hyun Min

    2010-11-15

    We show that the {mu} problem and the strong CP problem can be resolved in the context of the gauged U(1){sub R} symmetry, realizing an automatic Peccei-Quinn symmetry. In this scheme, right-handed neutrinos can be introduced to explain small Majorana or Dirac neutrino mass. The U(1){sub R} D-term mediated supersymmetry (SUSY) breaking, called the U(1){sub R} mediation, gives rise to a specific form of the flavor-conserving superpartner masses. For the given solution to the {mu} problem, electroweak symmetry breaking condition requires the superpartners of the standard model at low energy to be much heavier than the gravitino. Thus, the dark matter candidate can be either gravitino or right-handed sneutrino. In the Majorana neutrino case, only gravitino is a natural dark matter candidate. On the other hand, in the Dirac neutrino case, the right-handed sneutrino can be also a dark matter candidate as it gets mass only from SUSY breaking. We discuss the non-thermal production of our dark matter candidates from the late decay of stau and find that the constraints from the big bang nucleosynthesis can be evaded for a TeV-scale stau mass.

  18. Neutrinos from the terrestrial passage of supersymmetric dark-matter Q-balls

    SciTech Connect

    Kusenko, Alexander; Shoemaker, Ian M.

    2009-07-15

    Supersymmetry implies that stable nontopological solitons, Q-balls, could form in the early universe and could make up all or part of dark matter. We show that the relic Q-balls passing through Earth can produce a detectable neutrino flux. The peculiar zenith angle dependence and a small annual modulation of this flux can be used as signatures of dark-matter Q-balls.

  19. Multimomentum and multiflavor active-sterile neutrino oscillations in the early universe: Role of neutrino asymmetries and effects on nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Saviano, Ninetta; Mirizzi, Alessandro; Pisanti, Ofelia; Serpico, Pasquale Dario; Mangano, Gianpiero; Miele, Gennaro

    2013-04-01

    We perform a study of the flavor evolution in the early universe of a multiflavor active-sterile neutrino system with parameters inspired by the short-baseline neutrino anomalies. In a neutrino-symmetric bath a “thermal” population of the sterile state would quickly grow, but in the presence of primordial neutrino asymmetries a self-suppression as well as a resonant sterile neutrino production can take place, depending on temperature and chosen parameters. In order to characterize these effects, we go beyond the usual average momentum and single-mixing approximations and consider a multimomentum and multiflavor treatment of the kinetic equations. We find that the enhancement obtained in this case with respect to the average momentum approximation is significant, up to ˜20% of a degree of freedom. Such a detailed and computationally demanding treatment further raises the asymmetry values required to significantly suppress the sterile neutrino production, up to |Lν|≳O(10-2). For such asymmetries, however, the active-sterile flavor conversions happen so late that significant distortions are produced in the electron (anti)neutrino spectra. The larger |Lν|, the more the impact of these distortions takes over as a dominant cosmological effect, notably increasing the He4 abundance in primordial nucleosynthesis. The standard expression of the primordial yields in terms of the effective number of neutrinos and asymmetries is also greatly altered. We numerically estimate the magnitude of such effects for a few representative cases and comment on the implications for current cosmological measurements.

  20. Searching for keV Sterile Neutrino Dark Matter with X-Ray Microcalorimeter Sounding Rockets

    NASA Astrophysics Data System (ADS)

    Figueroa-Feliciano, E.; Anderson, A. J.; Castro, D.; Goldfinger, D. C.; Rutherford, J.; Eckart, M. E.; Kelley, R. L.; Kilbourne, C. A.; McCammon, D.; Morgan, K.; Porter, F. S.; Szymkowiak, A. E.; XQC Collaboration

    2015-11-01

    High-resolution X-ray spectrometers onboard suborbital sounding rockets can search for dark matter candidates that produce X-ray lines, such as decaying keV-scale sterile neutrinos. Even with exposure times and effective areas far smaller than XMM-Newton and Chandra observations, high-resolution, wide field of view observations with sounding rockets have competitive sensitivity to decaying sterile neutrinos. We analyze a subset of the 2011 observation by the X-ray Quantum Calorimeter instrument centered on Galactic coordinates l=165°,b=-5° with an effective exposure of 106 s, obtaining a limit on the sterile neutrino mixing angle of {{sin}}22θ < 7.2× {10}-10 at 95% CL for a 7 keV neutrino. Better sensitivity at the level of {{sin}}22θ ∼ 2.1× {10}-11 at 95% CL for a 7 keV neutrino is achievable with future 300-s observations of the galactic center by the Micro-X instrument, providing a definitive test of the sterile neutrino interpretation of the reported 3.56 keV excess from galaxy clusters.

  1. Dodelson-Widrow production of sterile neutrino Dark Matter with non-trivial initial abundance

    NASA Astrophysics Data System (ADS)

    Merle, Alexander; Schneider, Aurel; Totzauer, Maximilian

    2016-04-01

    The simplest way to create sterile neutrinos in the early Universe is by their admixture to active neutrinos. However, this mechanism, connected to the Dark Matter (DM) problem by Dodelson and Widrow (DW), cannot simulatenously meet the relic abundance constraint as well as bounds from structure formation and X-rays. Nonetheless, unless a symmetry forces active-sterile mixing to vanish exactly, the DW mechanism will unavoidably affect the sterile neutrino DM population created by any other production mechanism. We present a semi-analytic approach to the DW mechanism acting on an arbitrary initial abundance of sterile neutrinos, allowing to combine DW with any other preceeding production mechanism in a physical and precise way. While previous analyses usually assumed that the spectra produced by DW and another mechanism can simply be added, we use our semi-analytic results to discuss the validity of this assumption and to quantify its accurateness, thereby also scrutinising the DW spectrum and the derived mass bounds. We then map our results to the case of sterile neutrino DM from the decay of a real SM singlet coupled to the Higgs. Finally, we will investigate aspects of structure formation beyond the usual simple free-streaming estimates in order to judge on the effects of the DW modification on the sterile neutrino DM spectra generated by scalar decay.

  2. Possible capture of keV sterile neutrino dark matter on radioactive β-decaying nuclei

    NASA Astrophysics Data System (ADS)

    Li, Y. F.; Xing, Zhi-Zhong

    2011-01-01

    There exists an observed “desert” spanning six orders of magnitude between O(0.5) eV and O(0.5) MeV in the fermion mass spectrum. We argue that it might accommodate one or more keV sterile neutrinos as a natural candidate for warm dark matter. To illustrate this point of view, we simply assume that there is one keV sterile neutrino ν and its flavor eigenstate ν weakly mixes with three active neutrinos. We clarify different active-sterile neutrino mixing factors for the radiative decay of ν and β decays in a self-consistent parametrization. A direct detection of this keV sterile neutrino dark matter in the laboratory is in principle possible since the ν component of ν can leave a distinct imprint on the electron energy spectrum when it is captured on radioactive β-decaying nuclei. We carry out an analysis of its signatures in the capture reactions ν+H3→He3+e- and ν+Ru106→Rh106+e- against the β-decay backgrounds, and conclude that this experimental approach might not be hopeless in the long run.

  3. Hidden gauged U (1 ) model: Unifying scotogenic neutrino and flavor dark matter

    NASA Astrophysics Data System (ADS)

    Yu, Jiang-Hao

    2016-06-01

    In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario where the scotogenic neutrino and a flavored mediator share the same inert Higgs doublet and all are charged under a hidden gauged U (1 ) symmetry. The dark Z2 symmetry in the dark sector is regarded as the remnant of this hidden U (1 ) symmetry breaking. In particular, we investigate a dark U (1 )D [and also U (1 )B-L] model which unifies the scotogenic neutrino and top-flavored mediator. Thus dark tops and dark neutrinos are the standard model fermion partners, and the dark matter could be the inert Higgs or the lightest dark neutrino. We note that this model has rich collider signatures on dark tops, the inert Higgs and the Z' gauge boson. Moreover, the scalar associated to the U (1 )D [and also U (1 )B -L ] symmetry breaking could explain the 750 GeV diphoton excess reported by ATLAS and CMS recently.

  4. Nonlinear growing neutrino cosmology

    NASA Astrophysics Data System (ADS)

    Ayaita, Youness; Baldi, Marco; Führer, Florian; Puchwein, Ewald; Wetterich, Christof

    2016-03-01

    The energy scale of dark energy, ˜2 ×10-3 eV , is a long way off compared to all known fundamental scales—except for the neutrino masses. If dark energy is dynamical and couples to neutrinos, this is no longer a coincidence. The time at which dark energy starts to behave as an effective cosmological constant can be linked to the time at which the cosmic neutrinos become nonrelativistic. This naturally places the onset of the Universe's accelerated expansion in recent cosmic history, addressing the why-now problem of dark energy. We show that these mechanisms indeed work in the growing neutrino quintessence model—even if the fully nonlinear structure formation and backreaction are taken into account, which were previously suspected of spoiling the cosmological evolution. The attractive force between neutrinos arising from their coupling to dark energy grows as large as 106 times the gravitational strength. This induces very rapid dynamics of neutrino fluctuations which are nonlinear at redshift z ≈2 . Nevertheless, a nonlinear stabilization phenomenon ensures only mildly nonlinear oscillating neutrino overdensities with a large-scale gravitational potential substantially smaller than that of cold dark matter perturbations. Depending on model parameters, the signals of large-scale neutrino lumps may render the cosmic neutrino background observable.

  5. The Effect of Very Low Energy Solar Neutrinos on the MSW Mechanism

    NASA Astrophysics Data System (ADS)

    Esposito, S.

    We study some implications on standard matter oscillations of solar neutrinos induced by a background of extremely low energy thermal neutrinos trapped inside the Sun by means of coherent refractive interactions. Possible experimental tests are envisaged and current data on solar neutrinos detected at Earth are briefly discussed.

  6. Testing the big bang: Light elements, neutrinos, dark matter and large-scale structure

    SciTech Connect

    Schramm, D.N. Fermi National Accelerator Lab., Batavia, IL )

    1991-06-01

    In this series of lectures, several experimental and observational tests of the standard cosmological model are examined. In particular, detailed discussion is presented regarding nucleosynthesis, the light element abundances and neutrino counting; the dark matter problems; and the formation of galaxies and large-scale structure. Comments will also be made on the possible implications of the recent solar neutrino experimental results for cosmology. An appendix briefly discusses the 17 keV thing'' and the cosmological and astrophysical constraints on it. 126 refs., 8 figs., 2 tabs.

  7. Restrictions on parameters of sterile neutrino dark matter from observations of galaxy clusters

    SciTech Connect

    Boyarsky, A.; Shaposhnikov, M.; Ruchayskiy, O.

    2006-11-15

    We find restrictions on the mass and mixing angle of the dark matter sterile neutrinos using x-ray observations of Coma and Virgo galaxy clusters with XMM-Newton satellite. In the absence of clearly detectable line, we present detailed analysis of various methods of putting restrictions on mass and mixing angle of sterile neutrino. Our analysis provides significant improvement over our previous results, coming from XRB background measurements. We also discuss restrictions from Virgo cluster by other authors and compare our results with them.

  8. Supernova matter at subnuclear densities as a resonant Fermi gas: enhancement of neutrino rates.

    PubMed

    Bartl, A; Pethick, C J; Schwenk, A

    2014-08-22

    At low energies nucleon-nucleon interactions are resonant and therefore supernova matter at subnuclear densities has many similarities to atomic gases with interactions dominated by a Feshbach resonance. We calculate the rates of neutrino processes involving nucleon-nucleon collisions and show that these are enhanced in mixtures of neutrons and protons at subnuclear densities due to the large scattering lengths. As a result, the rate for neutrino pair bremsstrahlung and absorption is significantly larger below 10(13) g cm(-3) compared to rates used in supernova simulations. PMID:25192083

  9. AMEND: A Model Explaining Neutrino masses and Dark matter testable at the LHC and MEG

    NASA Astrophysics Data System (ADS)

    Farzan, Yasaman; Pascoli, Silvia; Schmidt, Michael A.

    2010-10-01

    Despite being very successful in explaining the wide range of precision experimental results obtained so far, the Standard Model (SM) of elementary particles fails to address two of the greatest observations of the recent decades: tiny but nonzero neutrino masses and the well-known problem of missing mass in the Universe. Typically the new models beyond the SM explain only one of these observations. Instead, in the present article, we take the view that they both point towards the same new extension of the Standard Model. The new particles introduced are responsible simultaneously for neutrino masses and for the dark matter of the Universe. The stability of dark matter and the smallness of neutrino masses are guaranteed by a U(1) global symmetry, broken to a remnant {mathbb{Z}_2} . The canonical seesaw mechanism is forbidden and neutrino masses emerge at the loop level being further suppressed by the small explicit breaking of the U(1) symmetry. The new particles and interactions are invoked at the electroweak scale and lead to rich phenomenology in colliders, in lepton flavour violating rare decays and in direct and indirect dark matter searches, making the model testable in the coming future.

  10. Dark matter decay to a photon and a neutrino: The double monochromatic smoking gun scenario

    NASA Astrophysics Data System (ADS)

    El Aisati, Chaïmae; Gustafsson, Michael; Hambye, Thomas; Scarna, Tiziana

    2016-02-01

    In the energy range from a few TeV to 25 TeV, upper bounds on the dark matter decay rate into high-energy monochromatic neutrinos have recently become comparable to those on monochromatic gamma-ray lines. This implies the clear possibility of a future double "smoking gun" as evidence of the dark matter particle, from the observation of both a gamma and a neutrino line at the same energy. In particular, we show that a scenario where both lines are induced from the same dark matter particle decay leads to correlations that can already be tested. We study this "double monochromatic" scenario by considering the complete list of lowest-dimensional effective operators that could induce such a decay. Furthermore, we argue that, on top of lines from decays into two-body final states, three-body final states can also be highly relevant. In addition to producing a distinct hard photon spectrum, three-body final states also produce a linelike feature in the neutrino spectrum that can be searched for with neutrino telescopes.

  11. Large-θ 13 perturbation theory of neutrino oscillation for long-baseline experiments

    NASA Astrophysics Data System (ADS)

    Asano, Katsuhiro; Minakata, Hisakazu

    2011-06-01

    The Cervera et al. formula, the best known approximate formula of neutrino oscillation probability for long-baseline experiments, can be regarded as a second-order perturbative formula with small expansion parameter ɛ ≡ ∆ m {21/2} ∆ m {31/2} ≃ 0 .03 under the 21assumption s 13 ≃ ɛ. If θ 13 is large, as suggested by a candidate ν e event at T2K as well as the recent global analyses, higher order corrections of s 13 to the formula would be needed for better accuracy. We compute the corrections systematically by formulating a perturbative framework by taking θ 13 as {s_{13}} ˜ sqrt { in } ˜eq 0.18 , which guarantees its validity in a wide range of θ 13 below the Chooz limit. We show on general ground that the correction terms must be of order ɛ2. Yet, they nicely fill the mismatch between the approximate and the exact formulas at low energies and relatively long baselines. General theorems are derived which serve for better understanding of δ-dependence of the oscillation probability. Some interesting implications of the large θ 13 hypothesis are discussed.

  12. Testing the Dark Matter Scenario for PeV Neutrinos Observed in IceCube.

    PubMed

    Murase, Kohta; Laha, Ranjan; Ando, Shin'ichiro; Ahlers, Markus

    2015-08-14

    Late time decay of very heavy dark matter is considered as one of the possible explanations for diffuse PeV neutrinos observed in IceCube. We consider implications of multimessenger constraints, and show that proposed models are marginally consistent with the diffuse γ-ray background data. Critical tests are possible by a detailed analysis and identification of the sub-TeV isotropic diffuse γ-ray data observed by Fermi and future observations of sub-PeV γ rays by observatories like HAWC or Tibet AS+MD. In addition, with several-year observations by next-generation telescopes such as IceCube-Gen2, muon neutrino searches for nearby dark matter halos such as the Virgo cluster should allow us to rule out or support the dark matter models, independently of γ-ray and anisotropy tests. PMID:26317706

  13. Dark matter and the solar neutrino problem: Can particle physics provide a single solution

    SciTech Connect

    West, G.B. )

    1989-01-01

    We show how a relatively simple extension of the standard model can give a natural'' explanation for both the solar neutrino and dark matter problems. What is required is a new stable neutral lepton with a mass in the 4--8 GeV range. One possibility is a fourth generation neutrino interacting with matter either electromagnetically or via higgs-exchange (in addition, of course, to Z{degree}-exchange). In the former case, a new charged lepton with mass {approximately}10GeV would be required in order to generate a sufficiently large magnetic moment. The present experimental situation makes this possibility rather doubtful. In the latter case, a light higgs with mass {approximately}1GeV is required; this is still not ruled out experimentally. In any case, direct (or indirect) detection of dark matter will, during the next year, seal the fate of this model. 29 refs.

  14. Is it possible to explain neutrino masses with scalar dark matter?

    SciTech Connect

    Boehm, Celine; Farzan, Yasaman; Hambye, Thomas; Palomares-Ruiz, Sergio; Pascoli, Silvia

    2008-02-15

    We present a scenario in which a remarkably simple relation linking dark matter properties and neutrino masses naturally emerges. This framework points towards a low energy theory where the neutrino mass originates from the existence of a light scalar dark matter particle in the keV-MeV mass range. We discuss different ways to constrain and test this scenario by means of astrophysical and cosmological observations as well as laboratory experiments. Finally, we point out that one interesting aspect is that the implied mass range is compatible with the one required for the explanation of the mysterious emission of 511 keV photons from the center of our galaxy in terms of dark matter annihilation into e{sup +}e{sup -} pairs.

  15. Satellite galaxies in semi-analytic models of galaxy formation with sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Lovell, Mark R.; Bose, Sownak; Boyarsky, Alexey; Cole, Shaun; Frenk, Carlos S.; Gonzalez-Perez, Violeta; Kennedy, Rachel; Ruchayskiy, Oleg; Smith, Alex

    2016-09-01

    The sterile neutrino is a viable dark matter candidate that can be produced in the early Universe via non-equilibrium processes, and would therefore possess a highly non-thermal spectrum of primordial velocities. In this paper we analyse the process of structure formation with this class of dark matter particles. To this end we construct primordial dark matter power spectra as a function of the lepton asymmetry, L6, that is present in the primordial plasma and leads to resonant sterile neutrino production. We compare these power spectra with those of thermally produced dark matter particles and show that resonantly produced sterile neutrinos are much colder than their thermal relic counterparts. We also demonstrate that the shape of these power spectra is not determined by the free-streaming scale alone. We then use the power spectra as an input for semi-analytic models of galaxy formation in order to predict the number of luminous satellite galaxies in a Milky Way-like halo. By assuming that the mass of the Milky Way halo must be no more than 2 × 1012 M⊙ (the adopted upper bound based on current astronomical observations) we are able to constrain the value of L6 for Ms ≤ 8 keV. We also show that the range of L6 that is in best agreement with the 3.5 keV line (if produced by decays of 7 keV sterile neutrino) requires that the Milky Way halo has a mass no smaller than 1.5 × 1012 M⊙. Finally, we compare the power spectra obtained by direct integration of the Boltzmann equations for a non-resonantly produced sterile neutrino with the fitting formula of Viel et al. and find that the latter significantly underestimates the power amplitude on scales relevant to satellite galaxies.

  16. Satellite galaxies in semi-analytic models of galaxy formation with sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Lovell, Mark R.; Bose, Sownak; Boyarsky, Alexey; Cole, Shaun; Frenk, Carlos S.; Gonzalez-Perez, Violeta; Kennedy, Rachel; Ruchayskiy, Oleg; Smith, Alex

    2016-06-01

    The sterile neutrino is a viable dark matter candidate that can be produced in the early Universe via non-equilibrium processes, and would therefore possess a highly non-thermal spectrum of primordial velocities. In this paper we analyse the process of structure formation with this class of dark matter particles. To this end we construct primordial dark matter power spectra as a function of the lepton asymmetry, L6, that is present in the primordial plasma and leads to resonant sterile neutrino production. We compare these power spectra with those of thermally produced dark matter particles and show that resonantly produced sterile neutrinos are much colder than their thermal relic counterparts. We also demonstrate that the shape of these power spectra are not determined by the free-streaming scale alone. We then use the power spectra as an input for semi-analytic models of galaxy formation in order to predict the number of luminous satellite galaxies in a Milky Way-like halo. By assuming that the mass of the Milky Way halo must be no more than 2 × 1012M⊙ (the adopted upper bound based on current astronomical observations) we are able to constrain the value of L6 for Ms ≤ 8 keV. We also show that the range of L6 that is in best agreement with the 3.5 keV line (if produced by decays of 7 keV sterile neutrino) requires that the Milky Way halo has a mass no smaller than 1.5 × 1012M⊙. Finally, we compare the power spectra obtained by direct integration of the Boltzmann equations for a non-resonantly produced sterile neutrino with the fitting formula of Viel et al. (2005) and find that the latter significantly underestimates the power amplitude on scales relevant to satellite galaxies.

  17. Leptonic CP violation studies at MiniBooNE in the (3+2) sterile neutrino oscillation hypothesis

    SciTech Connect

    Karagiorgi, G.; Aguilar-Arevalo, A.; Conrad, J. M.; Shaevitz, M. H.; Whisnant, K.; Sorel, M.; Barger, V.

    2007-01-01

    We investigate the extent to which leptonic CP-violation in (3+2) sterile neutrino models leads to different oscillation probabilities for {nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub e} oscillations at MiniBooNE. We are using a combined analysis of short-baseline (SBL) oscillation results, including the LSND and null SBL results, to which we impose additional constraints from atmospheric oscillation data. We obtain the favored regions in MiniBooNE oscillation probability space for both (3+2) CP-conserving and (3+2) CP-violating models. We further investigate the allowed CP-violation phase values and the MiniBooNE reach for such a CP violation measurement. The analysis shows that the oscillation probabilities in MiniBooNE neutrino and antineutrino running modes can differ significantly, with the latter possibly being as much as 3 times larger than the first. In addition, we also show that all possible values of the single CP-violation phase measurable at short baselines in (3+2) models are allowed within 99% CL by existing data.

  18. Highlights on gamma rays, neutrinos and antiprotons from TeV Dark Matter

    NASA Astrophysics Data System (ADS)

    Gammaldi, Viviana

    2016-07-01

    It has been shown that the gamma-ray flux observed by HESS from the J1745-290 Galactic Center source is well fitted as the secondary gamma-rays photons generated from Dark Matter annihilating into Standard Model particles in combination with a simple power law background. The neutrino flux expected from such Dark Matter source has been also analyzed. The main results of such analyses for 50 TeV Dark Matter annihilating into W+W- gauge boson and preliminary results for antiprotons are presented.

  19. Limits on dark matter proton scattering from neutrino telescopes using micrOMEGAs

    SciTech Connect

    Bélanger, G.; Silva, J. Da; Perrillat-Bottonet, T.; Pukhov, A.

    2015-12-17

    Limits on dark matter spin dependent elastic scattering cross section on protons derived from IceCube data are obtained for different dark matter annihilation channels using micrOMEGAs. The uncertainty on the derived limits, estimated by using different neutrino spectra, can reach a factor two. For all dark matter annihilation channels except for quarks, the limits on the spin dependent cross section are more stringent than those obtained in direct detection experiments. The new functions that allow to derive those limits are described.

  20. Cosmological and supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Shibagaki, S.; Suzuki, T.

    2014-06-01

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial 7Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and 7Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and 180Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ13 with predicted and observed supernova-produced abundance ratio 11B/7Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  1. Cosmological and supernova neutrinos

    SciTech Connect

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Suzuki, T.

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  2. Heavy right-handed neutrinos and dark matter in the {nu}CMSSM

    SciTech Connect

    Kadota, Kenji; Olive, Keith A.

    2009-11-01

    We perform a systematic study of the effects of the type-I seesaw mechanism on the dark matter abundance in the constrained minimal supersymmetric standard model (CMSSM) which includes three right-handed neutrinos (the {nu}CMSSM). For large values of m{sub 0}, m{sub 1/2}, we exploit the effects of large neutrino Yukawa couplings on the renormalization group evolution of the up-type Higgs. In particular, we show that the focus point scale can greatly exceed the electroweak scale resulting in the absence of a focus point region for which the relic density of neutralinos is within the range determined by WMAP. We also discuss the effects of the right-handed neutrinos on the so-called funnel region, where the relic density is controlled by s-channel annihilations through a heavy Higgs. For small values of m{sub 0}, m{sub 1/2}, we discuss the possibility of sneutrino coannihilation regions with an emphasis on the suppression of the left-handed slepton doublet masses due to the neutrino Yukawa coupling. We consider two types of toy models consistent with either the normal or inverted hierarchy of neutrino masses.

  3. New chiral fermions, a new gauge interaction, Dirac neutrinos, and dark matter

    NASA Astrophysics Data System (ADS)

    de Gouvêa, André; Hernández, Daniel

    2015-10-01

    We propose that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard-model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. Hypercharge, for example, plays this role for the SM fermions. We introduce a new symmetry, U(1) ν , for all new light fermionic states. Anomaly cancellations mandate the existence of several new fermion fields with nontrivial U(1) ν charges. We develop a concrete model of this type, for which we show that (i) some fermions remain massless after U(1) ν breaking — similar to SM neutrinos — and (ii) accidental global symmetries translate into stable massive particles — similar to SM protons. These ingredients provide a solution to the dark matter and neutrino mass puzzles assuming one also postulates the existence of heavy degrees of freedom that act as "mediators" between the two sectors. The neutrino mass mechanism described here leads to parametrically small Dirac neutrino masses, and the model also requires the existence of at least four Dirac sterile neutrinos. Finally, we describe a general technique to write down chiral-fermions-only models that are at least anomaly-free under a U(1) gauge symmetry.

  4. Resonant sterile neutrino dark matter in the local and high-z Universe

    NASA Astrophysics Data System (ADS)

    Bozek, Brandon; Boylan-Kolchin, Michael; Horiuchi, Shunsaku; Garrison-Kimmel, Shea; Abazajian, Kevork; Bullock, James S.

    2016-06-01

    Sterile neutrinos comprise an entire class of dark matter models that, depending on their production mechanism, can be hot, warm, or cold dark matter (CDM). We simulate the Local Group and representative volumes of the Universe in a variety of sterile neutrino models, all of which are consistent with the possible existence of a radiative decay line at ˜3.5 keV. We compare models of production via resonances in the presence of a lepton asymmetry (suggested by Shi & Fuller 1999) to `thermal' models. We find that properties in the highly non-linear regime - e.g. counts of satellites and internal properties of haloes and subhaloes - are insensitive to the precise fall-off in power with wavenumber, indicating that non-linear evolution essentially washes away differences in the initial (linear) matter power spectrum. In the quasi-linear regime at higher redshifts, however, quantitative differences in the 3D matter power spectra remain, raising the possibility that such models can be tested with future observations of the Lyman-α forest. While many of the sterile neutrino models largely eliminate multiple small-scale issues within the CDM paradigm, we show that these models may be ruled out in the near future via discoveries of additional dwarf satellites in the Local Group.

  5. A critical analysis of one-loop neutrino mass models with minimal dark matter

    NASA Astrophysics Data System (ADS)

    Ahriche, Amine; McDonald, Kristian L.; Nasri, Salah; Picek, Ivica

    2016-06-01

    A recent paper investigated minimal RνMDM models with the type T1-iii and T3 one-loop topologies. However, the candidate most-minimal model does not possess an accidental symmetry - the scalar potential contains an explicit symmetry breaking term, rendering the dark matter unstable. We present two models that cure this problem. However, we further show that all of the proposed minimal one-loop RνMDM models suffer from a second problem - an additional source of explicit Z2 symmetry breaking in the Yukawa sector. We perform a more-general analysis to show that neutrino mass models using either the type T3 or type T1-iii one-loop topologies do not give viable minimal dark matter candidates. Consequently, one-loop models of neutrino mass with minimal dark matter do not appear possible. Thus, presently there remains a single known (three-loop) model of neutrino mass that gives stable dark matter without invoking any new symmetries.

  6. Matter power spectra in viable f (R) gravity models with massive neutrinos

    NASA Astrophysics Data System (ADS)

    Geng, Chao-Qiang; Lee, Chung-Chi; Shen, Jia-Liang

    2015-01-01

    We investigate the matter power spectra in the power law and exponential types of viable f (R) theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, ∑mν, is allowed in the viable f (R) models than that in the ΛCDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get ∑mν < 0.451 (0.214) eV at 95% C.L. in the Starobinsky (exponential) model, while the corresponding one for the ΛCDM model is ∑mν < 0.200 eV. Furthermore, by treating the effective number of neutrino species Neff as a free parameter along with ∑mν, we find that Neff =3.78-0.84+0.64 (3.47-0.60+0.74) and ∑mν =0.533-0.411+0.254 (< 0.386) eV at 95% C.L. in the Starobinsky (exponential) model.

  7. High Energy Neutrino Astronomy and Neutrino Telescopes

    NASA Astrophysics Data System (ADS)

    Kouchner, A.

    2015-04-01

    Neutrinos constitute a unique probe since they escape from their sources, travel undisturbed on cosmological distances and are produced in high-energy (HE) hadronic processes. In particular they would allow a direct detection and unambiguous identification of the acceleration sites of HE baryonic cosmic rays (CR), which remain unknown. Recent results from the ICECUBE collaboration present the first highly significant indication for the detection of high-energy extraterrestrial neutrinos, after several decades of instrumental efforts. We briefly report on this important results which open the route for the high-energy neutrino astronomy era. We then focus on the ANTARES detector, which despite its modest size with respect to ICECUBE is the largest deep-sea neutrino telescope in the world. The primary goal is to search for astrophysical neutrinos in the TeV-PeV range. This comprises generic searches for any diffuse cosmic neutrino flux as well as more specific searches for astrophysical sources such as active galactic nuclei or Galactic sources. The search program also includes multi-messenger analyses based on time and/or space coincidences with other cosmic probes. The ANTARES observatory is sensitive to a wide-range of other phenomena, from atmospheric neutrino oscillations to dark matter annihilation or potential exotics such as nuclearites and magnetic monopoles. The most recent results are reported.

  8. High-energy neutrino signals from the Sun in dark matter scenarios with internal bremsstrahlung

    SciTech Connect

    Ibarra, Alejandro; Totzauer, Maximilian; Wild, Sebastian E-mail: maximilian.totzauer@mytum.de

    2013-12-01

    We investigate the prospects to observe a high energy neutrino signal from dark matter annihilations in the Sun in scenarios where the dark matter is a Majorana fermion that couples to a quark and a colored scalar via a Yukawa coupling. In this minimal scenario, the dark matter capture and annihilation in the Sun can be studied in a single framework. We find that, for small and moderate mass splitting between the dark matter and the colored scalar, the two-to-three annihilation q q-bar g plays a central role in the calculation of the number of captured dark matter particles. On the other hand, the two-to-three annihilation into q q-bar Z gives, despite its small branching fraction, the largest contribution to the neutrino flux at the Earth at the highest energies. We calculate the limits on the model parameters using IceCube observations of the Sun and we discuss their interplay with the requirement of equilibrium of captures and annihilations in the Sun and with the requirement of thermal dark matter production. We also compare the limits from IceCube to the limits from direct detection, antiproton measurements and collider searches.

  9. Sterile neutrino dark matter with gauged U(1){sub B-L} and a low reheating temperature

    SciTech Connect

    Khalil, Shaaban; Seto, Osamu

    2009-04-17

    Sterile right-handed neutrinos can be naturally embedded in a low scale gauged U(1){sub B-L} extension of the standard model. We show that, within a low reheating scenario, such a neutrino can be produced via a novel manner, namely scattering through Z' gauge boson, and becomes an interesting dark matter candidate. In addition, we show that if the neutrino mass is of the order of MeV, then it accounts for the measured dark matter relic density and also accommodates the observed flux of 511 keV photons from the galactic bulge.

  10. Cosmological constraints on neutrino plus axion hot dark matter: update after WMAP-5

    SciTech Connect

    Hannestad, S; Mirizzi, A; Raffelt, G G; Wong, Y Y Y E-mail: amirizzi@mppmu.mpg.de E-mail: ywong@mppmu.mpg.de

    2008-04-15

    We update our previous constraints on two-component hot dark matter (axions and neutrinos), including the recent WMAP five-year data release. Marginalizing over {Sigma}m{sub {nu}} provides m{sub a}<1.02 eV (95% C.L.) for the axion mass. In the absence of axions we find {Sigma}m{sub {nu}}<0.63 eV (95% C.L.)

  11. Testing nonunitarity of neutrino mixing matrices at neutrino factories

    SciTech Connect

    Goswami, Srubabati; Ota, Toshihiko

    2008-08-01

    In this paper we explore the effect of nonunitary neutrino mixing on neutrino oscillation probabilities both in vacuum and matter. In particular, we consider the {nu}{sub {mu}}{yields}{nu}{sub {tau}} channel and, using a neutrino factory as the source for {nu}{sub {mu}}'s, discuss the constraints that can be obtained on the moduli and phases of the parameters characterizing the violation of unitarity. We point out how the new CP violation phases present in the case where the nonunitary mixings give rise to spurious ''degenerate'' solutions in the parameter space. We also discuss how the true solutions can be extricated by combining measurements at several baselines.

  12. Neutrinos

    NASA Astrophysics Data System (ADS)

    Winter, K.; Murdin, P.

    2000-11-01

    Neutrinos are electrically neutral ELEMENTARY PARTICLES which experience only the weak nuclear force and gravity. Their existence was introduced as a hypothesis by Wolfgang Pauli in 1930 to explain the apparent violation of energy conservation in radioactive beta decay. Chadwick had discovered in 1914 that the energy spectrum of electrons emitted in beta decay was not monoenergetic but continuous...

  13. Constraining dark matter-neutrino interactions using the CMB and large-scale structure

    NASA Astrophysics Data System (ADS)

    Wilkinson, Ryan J.; Bœhm, Céline; Lesgourgues, Julien

    2014-05-01

    We present a new study on the elastic scattering cross section of dark matter (DM) and neutrinos using the latest cosmological data from Planck and large-scale structure experiments. We find that the strongest constraints are set by the Lyman-α forest, giving σDM-ν lesssim 10-33(mDM/GeV) cm2 if the cross section is constant and a present-day value of σDM-ν lesssim 10-45(mDM/GeV) cm2 if it scales as the temperature squared. These are the most robust limits on DM-neutrino interactions to date, demonstrating that one can use the distribution of matter in the Universe to probe dark (``invisible") interactions. Additionally, we show that scenarios involving thermal MeV DM and a constant elastic scattering cross section naturally predict (i) a cut-off in the matter power spectrum at the Lyman-α scale, (ii) Neff ~ 3.5 ± 0.4, (iii) H0 ~ 71 ± 3km s-1Mpc-1 and (iv) the possible generation of neutrino masses.

  14. Constraining dark matter-neutrino interactions using the CMB and large-scale structure

    SciTech Connect

    Wilkinson, Ryan J.; Boehm, Céline; Lesgourgues, Julien E-mail: julien.lesgourgues@cern.ch

    2014-05-01

    We present a new study on the elastic scattering cross section of dark matter (DM) and neutrinos using the latest cosmological data from Planck and large-scale structure experiments. We find that the strongest constraints are set by the Lyman-α forest, giving σ{sub DM−ν} ∼< 10{sup −33}(m{sub DM}/GeV) cm{sup 2} if the cross section is constant and a present-day value of σ{sub DM−ν} ∼< 10{sup −45}(m{sub DM}/GeV) cm{sup 2} if it scales as the temperature squared. These are the most robust limits on DM-neutrino interactions to date, demonstrating that one can use the distribution of matter in the Universe to probe dark (''invisible{sup )} interactions. Additionally, we show that scenarios involving thermal MeV DM and a constant elastic scattering cross section naturally predict (i) a cut-off in the matter power spectrum at the Lyman-α scale, (ii) N{sub eff} ∼ 3.5 ± 0.4, (iii) H{sub 0} ∼ 71 ± 3km s{sup −1}Mpc{sup −1} and (iv) the possible generation of neutrino masses.

  15. An improved Neutrino Oscillations Analysis of the MiniBooNE Data

    SciTech Connect

    Aguilar-Arevalo, Alexis Armando

    2008-01-01

    We calculate the exclusion region in the parameter space of vμ → v oscillations of the LSND type using a combined fit to the reconstructed energy distributions of neutrino candidate samples from the MiniBooNE data obtained with two different particle identification methods. The two ve candidate samples are included together with a high statistics sample of vμ events in the definition of a X2 statistic which includes the correlations between the energy intervals of all three samples and handles the event overlap between the ve samples. The vμ sample is introduced to constrain the effect of systematic uncertainties. This analysis increases the exclusion limit in the region Δm2≲ 1eV2 when compared with the result previously published by the collaboration, which used a different technique.

  16. CONCEPT DESIGN OF THE TARGET/HORN SYSTEM FOR THE BNL NEUTRINO OSCILLATION EXPERIMENT.

    SciTech Connect

    SIMOS,N.KIRK,H.KAHN,S.CARROL,A.LUDEWIG,H.WENG,W.T.DIWAN,M.RAPARIA,D.MCDONALD,K.EVANGELAKIS,G.

    2003-05-12

    The design concept for the integration of the target and the focusing horn system for the proposed BNL neutrino oscillation experiment is described in this paper. Also presented are issues associated with the functionality and thermo-mechanical response of the selected target intercepting the 28 GeV protons of the 1 MW upgraded AGS beam, the loading and mechanical response of the focusing horn subjected to high currents and energy deposited due to beam/target interaction, the integration of the two systems, and the heat removal schemes. The proposed target intercepts the 8.9 x 10{sup 13}, 28 GeV protons with a 2.5 Hz cycle time over a spot that encloses the 3{sigma} of the beam. In the baseline. design the inner conductor of the aluminum horn encloses the target while allowing for an annular space for forced cooling. Approximately 250 kA pulse of current of 20{micro}s duration will flow through the horn at 2.5 Hz repetition rate inducing high compressive forces, vibration and heat. The paper addresses these issues of horn mechanical response, heat removal scenario, and useful life estimation including radiation damage.

  17. Background Characterization for PROSPECT: a US Short-baseline Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Langford, Thomas

    2014-03-01

    Segmented antineutrino detectors placed near compact research reactors provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. The PROSPECT collaboration has developed a conceptual design for an experiment covering the favored reactor anomaly parameter space using two detectors located within 4-20 m of an existing reactor. Research reactors offer the benefits of compact cores, distinct reactor-off periods, and single-isotope fuel. However, they are typically located at ground level, providing little to no overburden to shield detectors. This talk will present the background requirements of the PROSPECT experiment and discuss feasibility studies that have been performed for three potential locations: NIST, INL, and ORNL. Two fast neutron detectors, a muon telescope, and HPGE and NaI gamma detectors have been deployed at the sites to measure reactor-related and cosmogenic backgrounds. The results of background measurements at each site during reactor operation and shutdown will be shown. Additionally, the planned techniques to reduce the impact of each background on the physics reach of the full experiment will also be discussed.

  18. Search for neutrino emission from relic dark matter in the sun with the Baikal NT200 detector

    NASA Astrophysics Data System (ADS)

    Avrorin, A. D.; Avrorin, A. V.; Aynutdinov, V. M.; Bannasch, R.; Belolaptikov, I. A.; Bogorodsky, D. Yu.; Brudanin, V. B.; Budnev, N. M.; Danilchenko, I. A.; Demidov, S. V.; Domogatsky, G. V.; Doroshenko, A. A.; Dyachok, A. N.; Dzhilkibaev, Zh.-A. M.; Fialkovsky, S. V.; Gafarov, A. R.; Gaponenko, O. N.; Golubkov, K. V.; Gress, T. I.; Honz, Z.; Kebkal, K. G.; Kebkal, O. G.; Konischev, K. V.; Konstantinov, E. N.; Korobchenko, A. V.; Koshechkin, A. P.; Koshel, F. K.; Kozhin, A. V.; Kulepov, V. F.; Kuleshov, D. A.; Ljashuk, V. I.; Milenin, M. B.; Mirgazov, R. A.; Osipova, E. R.; Panfilov, A. I.; Pan'kov, L. V.; Perevalov, A. A.; Pliskovsky, E. N.; Poleschuk, V. A.; Rozanov, M. I.; Rubtzov, V. F.; Rjabov, E. V.; Shaybonov, B. A.; Sheifler, A. A.; Shkurihin, A. V.; Smagina, A. A.; Suvorova, O. V.; Tarashansky, B. A.; Yakovlev, S. A.; Zagorodnikov, A. V.; Zhukov, V. A.; Zurbanov, V. L.

    2015-03-01

    We have analyzed a data set taken over 2.76 years live time with the Baikal neutrino telescope NT200. The goal of the analysis is to search for neutrinos from dark matter annihilation in the center of the Sun. Apart from the conventional annihilation channels b b bar , W+W- and τ+τ- we consider also the annihilation of dark matter particles into monochromatic neutrinos. From the absence of any excess of events from the direction of the Sun over the expected background, we derive 90% upper limits on the fluxes of muons and muon neutrinos from the Sun, as well as on the elastic cross sections of dark matter scattering on protons.

  19. Abelian gauge extension of the standard model: Dark matter and radiative neutrino mass

    NASA Astrophysics Data System (ADS)

    Borah, Debasish; Adhikari, Rathin

    2012-05-01

    We study a simple extension of the standard model where the gauge group is extended by an additional U(1)X gauge symmetry. Neutrino mass arises both at tree level as well as radiatively by the anomaly-free addition of one singlet fermion NR and two triplet fermions Σ1R, Σ2R with suitable Higgs scalars. The spontaneous gauge symmetry breaking is achieved in a way that results in a residual Z2 symmetry and hence provides a stable cold dark matter candidate. We study the possible dark matter candidates in this model by incorporating the constraints from cosmology as well as direct detection experiments. We discuss both low- and high-mass (from GeV to the TeV scale) regimes of fermionic and scalar dark matter candidates in the model. We show that scalar dark matter relic density, although not significantly affected by the presence or absence of annihilation into U(1)X gauge boson pairs, is however affected by choice of U(1)X gauge charges. We discuss the neutrino mass phenomenology and its compatibility with the allowed dark matter mass ranges and we also comment on the implications of the model on Higgs signatures at colliders including those related to the fourth fermion generation.

  20. Reproducing neutrino effects on the matter power spectrum through a degenerate Fermi gas approach

    NASA Astrophysics Data System (ADS)

    Perico, E. L. D.; Bernardini, A. E.

    2011-06-01

    Modifications on the predictions about the matter power spectrum based on the hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid to some dominant cosmological scenario are investigated. Reporting about the systematic way of accounting for all the cosmological perturbations, through the Boltzmann equation we obtain the analytical results for density fluctuation, δ, and fluid velocity divergence, θ, of the DFG. Small contributions to the matter power spectrum are analytically obtained for the radiation-dominated background, through an ultra-relativistic approximation, and for the matter-dominated and Λ-dominated eras, through a non-relativistic approximation. The results can be numerically reproduced and compared with those of considering non-relativistic and ultra-relativistic neutrinos into the computation of the matter power spectrum. Lessons concerning the formation of large scale structures of a DFG are depicted, and consequent deviations from standard ΛCDM predictions for the matter power spectrum (with and without neutrinos) are quantified.