WorldWideScience

Sample records for neutrino mass mechanism

  1. Neutrino Masses

    CERN Document Server

    Weinheimer, Christian

    2013-01-01

    The various experiments on neutrino oscillation evidenced that neutrinos have indeed non-zero masses but cannot tell us the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and the structure formation of the universe as well as for nuclear and particle physics beyond the present Standard Model. Complementary to deducing constraints on the sum of all neutrino masses from cosmological observations two different methods to determine the neutrino mass scale in the laboratory are pursued: the search for neutrinoless double $\\beta$-decay and the direct neutrino mass search by investigating single $\\beta$-decays or electron captures. The former method is not only sensitive to neutrino masses but also probes the Majorana character of neutrinos and thus lepton number violation with high sensitivity. Currently quite a few experiments with different techniques are being constructed, commissioned or are even running, which aim for a sensitivity on the neutrino ...

  2. Search for Neutrino Mass Generation Mechanisms with the ATLAS detector

    CERN Document Server

    Hamano, Kenji; The ATLAS collaboration

    2012-01-01

    There are two main theoretical frameworks to explain small but non-zero neutrino mass : seesaw mechanisms and radiative generation of neutrino masses. The Type II Seesaw models and the Zee-Babu two-loop mass generation model require new heavy scalars and the Type III Seesaw models predict a heavy fermion triplet. We search for those new particles in same-sign dilepton and three lepton final states. We present results with the data sample recorded in 2011 and/or 2012 by the ATLAS experiment at the LHC.

  3. How can we test the neutrino mass seesaw mechanism experimentally?

    Science.gov (United States)

    Buckley, Matthew R; Murayama, Hitoshi

    2006-12-01

    The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve data from the CERN Large Hadron Collider, International Linear Collider, cosmology, underground, and low-energy flavor experiments to establish the case.

  4. Leptoquark mechanism of neutrino masses within the grand unification framework

    Energy Technology Data Exchange (ETDEWEB)

    Dorsner, Ilja [University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB), Split (Croatia); Fajfer, Svjetlana; Kosnik, Nejc [University of Ljubljana, Department of Physics, Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, P. O. Box 3000, Ljubljana (Slovenia)

    2017-06-15

    We demonstrate the viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are S{sub 3}-R{sub 2} and S{sub 1,3}-R{sub 2}, respectively. We consider two distinct regimes for the LQ masses in our analysis. The first regime calls for very heavy LQs in the loop. It can be naturally realized with the S{sub 1,3}-R{sub 2} scenarios when the LQ masses are roughly between 10{sup 12} and 5 x 10{sup 13} GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the S{sub 3}-R{sub 2} scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the S{sub 3}-R{sub 2} scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of SU(5). We furthermore discuss several possible embeddings of this mechanism in SU(5) and SO(10) gauge groups. (orig.)

  5. Leptoquark mechanism of neutrino masses within the grand unification framework

    Science.gov (United States)

    Doršner, Ilja; Fajfer, Svjetlana; Košnik, Nejc

    2017-06-01

    We demonstrate the viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are S_3-R_2 and S_{1, 3}-\\tilde{R}_2, respectively. We consider two distinct regimes for the LQ masses in our analysis. The first regime calls for very heavy LQs in the loop. It can be naturally realized with the S_{1, 3}-\\tilde{R}_2 scenarios when the LQ masses are roughly between 10^{12} and 5 × 10^{13} GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the S_3-\\tilde{R}_2 scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the S_3-R_2 scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of SU(5). We furthermore discuss several possible embeddings of this mechanism in SU(5) and SO(10) gauge groups.

  6. Absolute neutrino mass update

    CERN Document Server

    Päs, H; P\\"as, Heinrich; Weiler, Thomas J.

    2002-01-01

    The determination of absolute neutrino masses is crucial for the understanding of theories underlying the standard model, such as SUSY. We review the experimental prospects to determine absolute neutrino masses and the correlations among approaches, using the Delta m^2's inferred from neutrino oscillation experiments and assuming a three neutrino Universe.

  7. ABSOLUTE NEUTRINO MASSES

    DEFF Research Database (Denmark)

    Schechter, J.; Shahid, M. N.

    2012-01-01

    We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos.......We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos....

  8. Testing neutrino mass generation mechanisms from the lepton flavor violating decay of the Higgs boson

    Science.gov (United States)

    Aoki, Mayumi; Kanemura, Shinya; Sakurai, Kodai; Sugiyama, Hiroaki

    2016-12-01

    We investigate how observations of the lepton flavor violating decay of the Higgs boson (h → ℓℓ‧) can narrow down models of neutrino mass generation mechanisms, which were systematically studied in Refs. [1,2] by focusing on the combination of new Yukawa coupling matrices with leptons. We find that a wide class of models for neutrino masses can be excluded if evidence for h → ℓℓ‧ is really obtained in the current or future collider experiments. In particular, simple models of Majorana neutrino masses cannot be compatible with the observation of h → ℓℓ‧. It is also found that some of the simple models to generate masses of Dirac neutrinos radiatively can be compatible with a significant rate of the h → ℓℓ‧ process.

  9. Testing neutrino mass generation mechanisms from the lepton flavor violating decay of the Higgs boson

    CERN Document Server

    Aoki, Mayumi; Sakurai, Kodai; Sugiyama, Hiroaki

    2016-01-01

    We investigate how observations of the lepton flavor violating decay of the Higgs boson ($h \\to \\ell\\ell^\\prime$) can narrow down models of neutrino mass generation mechanisms, which were systematically studied in Refs. [1,2] by focusing on the combination of new Yukawa coupling matrices with leptons. We find that a wide class of models for neutrino masses can be excluded if evidence for $h \\to \\ell\\ell^\\prime$ is really obtained in the current or future collider experiments. In particular, simple models of Majorana neutrino masses cannot be compatible with the observation of $h \\to \\ell\\ell^\\prime$. It is also found that some of the simple models to generate masses of Dirac neutrinos radiatively can be compatible with a significant rate of the $h \\to \\ell\\ell^\\prime$ process.

  10. Neutrino Masses and Flavor Mixing

    Science.gov (United States)

    Xing, Zhi-zhong

    2010-06-01

    I give a theoretical overview of some basic properties of massive neutrinos in these lectures. Particular attention is paid to the origin of neutrino masses, the pattern of lepton flavor mixing, the feature of leptonic CP violation and the electromagnetic properties of massive neutrinos. I highlight the TeV seesaw mechanisms as a possible bridge between neutrino physics and collider physics in the era characterized by the Large Hadron Collider.

  11. Neutrino Oscillations with Nil Mass

    CERN Document Server

    Floyd, Edward R

    2016-01-01

    An alternative neutrino oscillation process is presented as a counterexample for which the neutrino may have nil mass consistent with the standard model. The process is developed in a quantum trajectories representation of quantum mechanics, which has a Hamilton-Jacobi foundation. This process has no need for mass differences between mass eigenstates. Flavor oscillations and $\\bar{\

  12. Neutrino Oscillations with Nil Mass

    Science.gov (United States)

    Floyd, Edward R.

    2016-09-01

    An alternative neutrino oscillation process is presented as a counterexample for which the neutrino may have nil mass consistent with the standard model. The process is developed in a quantum trajectories representation of quantum mechanics, which has a Hamilton-Jacobi foundation. This process has no need for mass differences between mass eigenstates. Flavor oscillations and ν ,bar{ν } oscillations are examined.

  13. Scaling in the Neutrino Mass Matrix, mu-tau Symmetry and the See-Saw Mechanism

    CERN Document Server

    Joshipura, Anjan S

    2009-01-01

    The scaling hypothesis postulates proportionality of two columns of the Majorana neutrino mass matrix in the flavor basis. This Ansatz was shown to lead to an inverted hierarchy and U_{e3} = 0. We discuss theoretical and phenomenological properties of this hypothesis. We show that (i) the neutrino mass matrix with scaling follows as a consequence of a generalized mu-tau symmetry imposed on the type-I see-saw model; (ii) there exists a unique texture for the Dirac mass matrix m_D which leads to scaling for arbitrary Majorana matrix M_R in the context of the type-I see-saw mechanism; (iii) unlike in the mu-tau symmetric case, a simple model with two right-handed neutrinos and scaling can lead to successful leptogenesis both with and without the inclusion of flavor effects.

  14. Scaling in the neutrino mass matrix, {mu}-{tau} symmetry and the see-saw mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Joshipura, Anjan S. [Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, Gujarat (India)], E-mail: anjan@prl.res.in; Rodejohann, Werner [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)], E-mail: werner.rodejohann@mpi-hd.mpg.de

    2009-07-20

    The scaling hypothesis postulates proportionality of two columns of the Majorana neutrino mass matrix in the flavor basis. This ansatz was shown to lead to an inverted hierarchy and U{sub e3}=0. We discuss theoretical and phenomenological properties of this hypothesis. We show that (i) the neutrino mass matrix with scaling follows as a consequence of a generalized {mu}-{tau} symmetry imposed on the type-I see-saw model; (ii) there exists a unique texture for the Dirac mass matrix m{sub D} which leads to scaling for arbitrary Majorana matrix M{sub R} in the context of the type-I see-saw mechanism; (iii) unlike in the {mu}-{tau} symmetric case, a simple model with two right-handed neutrinos and scaling can lead to successful leptogenesis both with and without the inclusion of flavor effects.

  15. Multiple seesaw mechanisms of neutrino masses at the TeV scale

    CERN Document Server

    Xing, Zhi-zhong

    2009-01-01

    In pursuit of a balance between theoretical naturalness and experimental testability, we propose two classes of multiple seesaw mechanisms at the TeV scale to understand the origin of tiny neutrino masses. They are novel extensions of the canonical and double seesaw mechanisms, respectively, by introducing even and odd numbers of gauge-singlet fermions and scalars. It is thanks to a proper implementation of the global U(1)xZ_2N symmetry that the overall neutrino mass matrix in either class has a suggestive nearest-neighbor-interaction pattern. We briefly discuss possible consequences of these TeV-scale seesaw scenarios, which can hopefully be explored in the upcoming Large Hadron Collider and precision neutrino experiments, and present a simple but instructive example of model building.

  16. Stochastic Neutrino Mixing Mechanism

    CERN Document Server

    Guzzo, M M; Peres, O L G; Zavanin, E M

    2013-01-01

    We propose a mechanism which provides an explanation of the Gallium and antineutrino reactor anomalies. Differently from original Pontecorvo's hypothesis, this mechanism is based on the phenomenological assumption in which the admixture of neutrino mass eigenstates in the moments of neutrino creation and detection can assume different configurations around the admixture parametrized by the usual values of the mixing angles $\\theta_{12}$, $\\theta_{23}$ and $\\theta_{13}$. For simplicity, we assume a Gaussian distribution for the mixing angles in such a way that the average value of this distribution is given by the usual values of the mixing angles and the width of the Gaussian is denoted by $\\alpha$. We show that the proposed mechanism provides a possible explanation for very short-baseline neutrino disappearance, necessary to accommodate Gallium and antineutrino reactor anomalies, which is not allowed in usual neutrino oscillations based on Pontecorvo's original hypotheses. We also can describe high-energy os...

  17. Neutrino Masses and Oscillations

    CERN Document Server

    Valle, J W F

    2005-01-01

    I summarize the status of three--neutrino oscillations that follow from combining the relevant world's data. The discussion includes the small parameters Delta_m-sol/Delta_m-atm and \\sin^2\\theta_{13}, which characterize the strength of CP violation in neutrino oscillations, the impact of oscillation data on the prospects for probing the absolute scale of neutrino mass in \

  18. Neutrinos Mass and Mixing

    CERN Document Server

    González-Garciá, M Concepción

    1998-01-01

    I review the status of neutrino masses and mixings in the light of the solar and atmospheric neutrino data. The result from the LSND experiment and the possible role of neutrinos as hot dark matter are also included. I also discuss the simplest schemes proposed to reconcile these data which include a light sterile neutrino in addition to the three standard ones. Implications for future experiments are commented.

  19. Direct neutrino mass measurements

    Science.gov (United States)

    Thümmler, T.

    2011-07-01

    The determination of the neutrino rest mass plays an important role at the intersections of cosmology, particle physics and astroparticle physics. This topic is currently being addressed by two complementary approaches in laboratory experiments. Neutrinoless double beta decay experiments probe whether neutrinos are Majorana particles and determine an effective neutrino mass value. Single beta decay experiments such as KATRIN and MARE investigate the spectral shape of β-decay electrons close to their kinematic endpoint in order to determine the neutrino rest mass with a model-independent method. Owing to neutrino flavour mixing, the neutrino mass parameter appears as an average of all neutrino mass eigenstates contributing to the electron neutrino. The KArlsruhe TRItium Neutrino experiment (KATRIN) is currently the experiment in the most advanced status of commissioning. Applying an ultra-luminous molecular windowless gaseous tritium source and an integrating high-resolution spectrometer of MAC-E filter type, it allows β-spectroscopy close to the T 2 end-point with unprecedented precision and will reach a sensitivity of 200 meV/ c 2 (90% C.L.) on the neutrino rest mass.

  20. Neutrino masses and deviation from tribimaximal mixing in Δ (27 ) model with inverse seesaw mechanism

    Science.gov (United States)

    Abbas, Mohammed; Khalil, Shaaban; Rashed, Ahmed; Sil, Arunansu

    2016-01-01

    We propose a scheme, based on Δ (27 ) flavor symmetry and supplemented by other discrete symmetries and the inverse seesaw mechanism, where both the light neutrino masses and the deviation from tribimaximal mixing matrix can be linked to the source of lepton number violation. The hierarchies of the charged leptons are explained. We find that the quark masses including their hierarchies and the mixing can also be constructed in a similar way.

  1. Radiative origin of neutrino masses

    CERN Document Server

    Aristizabal Sierra, D

    2015-01-01

    Mechanisms for Majorana neutrino mass generation can be classified according to the level at which the Weinberg operator is generated. The different possibilities can be sorted in "canonical" tree level and loop-induced realizations, the latter being motivated by their potential experimental testability. Here we discuss the one- and two-loop cases, paying special attention to systematic classification schemes which aim at building a full picture of neutrino mass generation.

  2. Absolute Neutrino Mass Determination

    CERN Document Server

    Päs, H

    2001-01-01

    We discuss four approaches to the determination of absolute neutrino mass. These are the measurement of the zero-neutrino double beta decay rate, of the tritium decay end-point spectrum, of the cosmic ray spectrum above the GZK cutoff, and the cosmological measurement of the power spectrum governing the CMB and large scale structure. The first two approaches are sensitive to the mass eigenstates coupling to the electron neutrino, whereas the latter two are sensitive to the heavy component of the cosmic neutrino background. All mass eigenstates are related by the $\\Delta m^2$'s inferred from neutrino oscillation data. Consequently, the potential for absolute mass determination of each of the four approaches is correlated with the other three, in ways that we point out.

  3. Leptogenesis. Theory and neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.

    2012-12-15

    After a brief discussion of baryon and lepton number nonconservation, we review the status of thermal leptogenesis with GUT scale neutrino masses, as well as low scale alternatives with keV neutrinos as dark matter and heavy neutrino masses within the reach of the LHC. Recent progress towards a full quantum mechanical description of leptogenesis is described with resonant leptogenesis as an application. Finally, cosmological B-L breaking after inflation is considered as origin of the hot early universe, generating entropy, baryon asymmetry and dark matter.

  4. Neutrino mass mechanisms in 3-3-1 models: A short review

    CERN Document Server

    Pires, C A de S

    2014-01-01

    In this paper we review some mechanisms that provide light neutrinos in the framework of 3-3-1 gauge models without exotic leptons. In regard to the minimal 3-3-1 model, we call the attention to the fact that the perturbative regime of the model goes until 5 TeV. This requires alternative mechanisms in order to generate light neutrinos. In this review we discuss two mechanisms capable of generating light neutrinos in the framework of the minimal 3-3-1 model. In regard to the 3-3-1 model with right-handed neutrinos, we call the attention to the fact that in it mechanisms that generate light left-handed neutrinos also generate light right-handed neutrinos. Finally, we call the attention to the fact that the 3-3-1 model with right-handed neutrinos accommodate naturally the inverse seesaw mechanism.

  5. Neutrino mass from M theory SO(10)

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Bobby S. [Department of Physics, King’s College,WC2R 2LS, London (United Kingdom); International Centre for Theoretical Physics,I-34151 Trieste (Italy); Bożek, Krzysztof [Department of Physics, King’s College,WC2R 2LS, London (United Kingdom); Romão, Miguel Crispim; King, Stephen F. [School of Physics and Astronomy, University of Southampton,SO17 1BJ, Southampton (United Kingdom); Pongkitivanichkul, Chakrit [Department of Physics, King’s College,WC2R 2LS, London (United Kingdom)

    2016-11-29

    We study the origin of neutrino mass from SO(10) arising from M Theory compactified on a G{sub 2}-manifold. This is linked to the problem of the breaking of the extra U(1) gauge group, in the SU(5)×U(1) subgroup of SO(10), which we show can achieved via a (generalised) Kolda-Martin mechanism. The resulting neutrino masses arise from a combination of the seesaw mechanism and induced R-parity breaking contributions. The rather complicated neutrino mass matrix is analysed for one neutrino family and it is shown how phenomenologically acceptable neutrino masses can emerge.

  6. Neutrino mass from M Theory SO(10)

    CERN Document Server

    Acharya, Bobby S; Romão, Miguel Crispim; King, Stephen F; Pongkitivanichkul, Chakrit

    2016-01-01

    We study the origin of neutrino mass from $SO(10)$ arising from $M$ Theory compactified on a $G_2$-manifold. This is linked to the problem of the breaking of the extra $U(1)$ gauge group, in the $SU(5)\\times U(1)$ subgroup of $SO(10)$, which we show can achieved via a (generalised) Kolda-Martin mechanism. The resulting neutrino masses arise from a combination of the seesaw mechanism and induced R-parity breaking contributions. The rather complicated neutrino mass matrix is analysed for one neutrino family and it is shown how phenomenologically acceptable neutrino masses can emerge.

  7. Signatures of the neutrino mass hierarchy in supernova neutrinos

    CERN Document Server

    Chiu, S H; Lai, Kwang-Chang

    2013-01-01

    The undetermined neutrino mass hierarchy may leave observable imprint on the neutrino fluxes from the core-collpse supernova (SN). The interpretation of the observables, however, is subject to the uncertain SN models and the flavor conversion mechanism of neutrinos in a SN. We attempt to propose a qualitative and model-independent interpretation of the expected neutrino events at terrestrial detectors, focusing on the accretion phase of the neutrino burst. The flavor conversions due to the neutrino self-interaction, the MSW effect, and the Earth regeneration effect are incorporated in the calculation. It leads to several distinct scenarios that are identified by the neutrino mass hierarchies and the collective flavor transitions. Consequences resulting from the variation of incident angles and SN models are also discussed.

  8. Few active mechanisms of the neutrinoless double beta-decay and effective mass of Majorana neutrinos

    CERN Document Server

    Simkovic, Fedor; Faessler, Amand

    2010-01-01

    It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay (0nbb-decay). By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, assuming the observation of the 0nbb-decay in three different nuclei, e.g., 76Ge, 100Mo and 130Te, and just three lepton number violating mechanisms (light and heavy neutrino mass mechanisms as well as R-parity breaking SUSY mechanism) being active, there are only four different solutions for the lepton violating parameters, provided that they are relatively real. In particular, assuming evidence of the 0nbb-decay of 76Ge, the effective neutrino Majorana mass |m_bb| can be almost uniquely extracted by utilizing other existing constraints (cosmological observations and tritium beta-decay ex...

  9. Leptogenesis models and neutrino mass constraints

    Indian Academy of Sciences (India)

    T Hambye

    2006-10-01

    Through leptogenesis, baryogenesis could have the same origin as neutrino masses. We review the various ways of implementing the leptogenesis mechanism. Emphasis is put on the conditions which, in order that this mechanism works, need to be fulfilled by the neutrino masses as well as by the heavy state masses.

  10. Mass of neutrino and particle physics

    CERN Document Server

    Yanagida, T

    2003-01-01

    We give a brief review on the seesaw mechanism in a grand unified theory which predicts small neutrino masses. In the seesaw mechanism the lepton-number conservation is broken and neutrinos have Majorana type masses. We also explain why the lepton-number nonconservation can be an origin of the baryon-number asymmetry in the present universe. (author)

  11. Understanding neutrino masses and mixings

    Indian Academy of Sciences (India)

    R N Mohapatra

    2004-02-01

    We discuss ways to understand large neutrino mixings using new symmetries of quarks and leptons beyond the standard model for the three allowed patterns of neutrino masses: normal, inverted hierarchy and degenerate masses.

  12. Riddle of the Neutrino Mass

    CERN Document Server

    Smirnov, A Yu

    2015-01-01

    We discuss some known approaches and results as well as few new ideas concerning origins and nature of neutrino mass. The key issues include (i) connections of neutrino and charged fermions masses, relation between masses and mixing, energy scale of new physics behind neutrino mass where possibilities spread from the Planck and GUT masses down to a sub-eV scale. The data hint two different new physics involved in generation of neutrino mass. Determination of the CP phase as well as mass hierarchy can play important role in identification of new physics. It may happen that sterile neutrinos provide the key to resolve the riddle.

  13. Off-diagonal structure of neutrino mass matrix in see-saw mechanism and electron-muon-tau lepton universality

    CERN Document Server

    Riazuddin, M

    2001-01-01

    By a simple extension of the standard model in which ($e-\\mu -\\tau $) universality is not conserved, we present a scenario within the framework of see-saw mechanism in which the neutrino mass matrix is strictly off-diagonal in the flavor basis. We show that a version of this scenario can accomodate the atmospheric $\

  14. Neutrinos: recent developments and origin of neutrino mass matrix

    CERN Document Server

    Riazuddin

    2004-01-01

    Certainly one of the most exciting areas of research at present is neutrino physics. The neutrinos are fantastically numerous in the universe and as such they have bearing on our understanding of the universe. Therefore, we must understand the neutrinos, particularly their mass. There is compelling evidence from solar and atmospheric neutrinos and those from reactors for neutrino oscillations implying that neutrinos mix and have nonzero mass but without pinning down their absolute mass. This is reviewed. The implications of neutrino oscillations and mass squared splitting between neutrinos of different flavor on pattern of neutrino mass matrix is discussed. In particular, a neutrino mass matrix, which shows approximate flavor symmetry where the neutrino mass differences arise from flavor violation in off-diagonal Yukawa couplings is elaborated on. The implications in double beta decay are also discussed.

  15. On the Higgs potential in a model with spontaneous parity violation and neutrino masses in the inverse see-saw mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Malta, P.C.; Candido, M.M; Simoes, J.A.M.; Ramalho, A.J. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica. Dept. de Fisica Teorica

    2011-07-01

    Full text: There is an increasing experimental evidence for neutrino oscillations coming from atmospheric, solar and reactor neutrino experiments. These results imply that neutrinos have small masses. A known mechanism to generate neutrino masses is the so called 'canonical see-saw', which provides tiny masses to observed neutrinos. Despite of this achievement, this model also predicts extremely heavy neutrinos, currently unattainable to experiment. An alternative to this undesirable feature is the 'inverse see-saw' , which does not involve symmetry breaking energy scales far beyond a few TeV. In this work we use this mechanism in a model with spontaneous parity violation and gauge structure SU(2){sub R} x SU(2){sub L} x U(1){sub B-L}. We shall study both the Higgs potential and sector in order to find experimental consequences that could be sought for at the LHC. (author)

  16. Neutrino Masses and Deviation from Tri-bimaximal mixing in \\Delta(27) model with Inverse Seesaw Mechanism

    CERN Document Server

    Abbas, M; Rashed, A; Sil, A

    2016-01-01

    We propose a scheme, based on \\Delta(27) flavor symmetry and supplemented by other discrete symmetries and inverse seesaw mechanism, where both the light neutrino masses and the deviation from tri-bimaximal mixing matrix can be linked to the source of lepton number violation. The hierarchies of the charged leptons are explained. We find that the quark masses including their hierarchies and the mixing can also be constructed in a similar way.

  17. Dirac Neutrino Masses in NCG

    Institute of Scientific and Technical Information of China (English)

    LI Chang-Hui; DING Hao-Gang; DAI Jian; SONG Xing-Chang

    2001-01-01

    Several models in noncommutative geometry (NCG) with mild changes to the standard model are introduced to discuss the neutrino mass problem. We use two constraints, Poincaré duality and gauge anomaly free, to discuss the possibility of containing right-handed neutrinos in them. Our work shows that no model in this paper, with each generation containing a right-handed neutrino, can satisfy these two constraints at the same time. So, to consist with neutrino oscillation experiment results, maybe fundamental changes to the present version of NCG are usually needed to include Dirac massive neutrinos.

  18. Parity violation and neutrino mass

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Besides the fact of parity violation in weak interactions, based on evidences from neutrino oscillation and tritium beta decay, a natural conjecture is hat neutrinos may be spacelike particles with a tiny proper mass. A Dirac-type equation for spacelike neutrinos is further investigated and its solutions are discussed. This equation can be written in two spinor equations coupled together via nonzero proper mass while respecting maximum parity violation.

  19. Neutrino Masses and Flavor Oscillations

    Science.gov (United States)

    Wang, Yifang; Xing, Zhi-Zhong

    2016-10-01

    This essay is intended to provide a brief description of the peculiar properties of neutrinos within and beyond the standard theory of weak interactions. The focus is on the flavor oscillations of massive neutrinos, from which one has achieved some striking knowledge about their mass spectrum and flavor mixing pattern. The experimental prospects towards probing the absolute neutrino mass scale, possible Majorana nature and CP-violating effects, will also be addressed.

  20. Gauge Trimming of Neutrino Masses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mu-Chun; /Fermilab /UC, Irvine; de Gouvea, Andre; /Northwestern U. /Fermilab; Dobrescu, Bogdan A.; /Fermilab

    2006-12-01

    We show that under a new U(1) gauge symmetry, which is non-anomalous in the presence of one ''right-handed neutrino'' per generation and consistent with the standard model Yukawa couplings, the most general fermion charges are determined in terms of four rational parameters. This generalization of the B-L symmetry with generation-dependent lepton charges leads to neutrino masses induced by operators of high dimensionality. Neutrino masses are thus naturally small without invoking physics at energies above the TeV scale, whether neutrinos are Majorana or Dirac fermions. This ''Leptocratic'' Model predicts the existence of light quasi-sterile neutrinos with consequences for cosmology, and implies that collider experiments may reveal the origin of neutrino masses.

  1. Probing neutrino masses with neutrino-speed experiments

    CERN Document Server

    Ahluwalia, D V; Schritt, D

    2011-01-01

    Quantum field theoretic calculations generically predict a finite probability amplitude for propagation between two points separated by a space-like separation. For most elementary particles these quantum mechanical excursions outside the light cone turn out to be exceedingly limited. For a spatial excursion r, the amplitudes fall off as e^(-r/lambda_c). However, now there are strong indications that neutrino physics probes very small mass scales. Here we show that if the existing MINOS and OPERA neutrino-speed results are interpreted as arising primarily from such quantum field theoretic amplitudes, then these require the lowest mass eigenstate of neutrinos to be around 1.1 \\times 10^(-8) eV . Taken together with the global neutrino oscillation data, the other mass eigenstates turn out to be 8.7 \\times 10^(-3) eV and 4.9 \\times 10^(-2) eV . We argue that a new generation of short baseline neutrino experiments are now capable of directly probing absolute values of neutrino mass eigenstates.

  2. Cosmo MSW effect for mass varying neutrinos

    CERN Document Server

    Hung, P Q; Hung, Pham Quang; P\\"as, Heinrich

    2003-01-01

    We consider neutrinos with varying masses which arise in scenarios relating neutrino masses to the dark energy density in the universe. We point out that the neutrino mass variation can lead to level crossing and thus a cosmo MSW effect, having dramatic consequences for the flavor ratio of astrophysical neutrinos and the composition of the relic neutrino background.

  3. Neutrino Masses and GUT Baryogenesis

    CERN Document Server

    López-Pérez, J A

    2003-01-01

    We reconsider the GUT-baryogenesis mechanism for generating the baryon asymmetry of the Universe. The baryon asymmetry is produced by the out of equilibrium decay of coloured Higgs bosons at the GUT scale, conserving B-L. If neutrinos are Majorana particles, lepton number violating interactions erase the lepton number excess, but part of the baryon asymmetry may be preserved, provided those interactions are not in thermal equilibrium when the sphaleron processes become effective, at $T \\sim 10^{12}~ GeV$. We analyse whether this mechanism for baryogenesis is feasible in a variety of GUT models of fermion masses proposed in the literature, based on horizontal symmetries.

  4. Neutrino mass and mixing in the seesaw playground

    Energy Technology Data Exchange (ETDEWEB)

    King, Stephen F., E-mail: king@soton.ac.uk

    2016-07-15

    We discuss neutrino mass and mixing in the framework of the classic seesaw mechanism, involving right-handed neutrinos with large Majorana masses, which provides an appealing way to understand the smallness of neutrino masses. However, with many input parameters, the seesaw mechanism is in general not predictive. We focus on natural implementations of the seesaw mechanism, in which large cancellations do not occur, where one of the right-handed neutrinos is dominantly responsible for the atmospheric neutrino mass, while a second right-handed neutrino accounts for the solar neutrino mass, leading to an effective two right-handed neutrino model. We discuss recent attempts to predict lepton mixing and CP violation within such natural frameworks, focusing on the Littlest Seesaw and its distinctive predictions.

  5. Neutrino mass and mixing in the seesaw playground

    Science.gov (United States)

    King, Stephen F.

    2016-07-01

    We discuss neutrino mass and mixing in the framework of the classic seesaw mechanism, involving right-handed neutrinos with large Majorana masses, which provides an appealing way to understand the smallness of neutrino masses. However, with many input parameters, the seesaw mechanism is in general not predictive. We focus on natural implementations of the seesaw mechanism, in which large cancellations do not occur, where one of the right-handed neutrinos is dominantly responsible for the atmospheric neutrino mass, while a second right-handed neutrino accounts for the solar neutrino mass, leading to an effective two right-handed neutrino model. We discuss recent attempts to predict lepton mixing and CP violation within such natural frameworks, focusing on the Littlest Seesaw and its distinctive predictions.

  6. The KATRIN Neutrino Mass Experiment

    Science.gov (United States)

    Parno, Diana; Katrin Collaboration

    2017-01-01

    While neutrino oscillation experiments have demonstrated that the particles have non-zero mass, the absolute neutrino mass scale is still unknown. The Karlsruhe Tritium Neutrino experiment (KATRIN) is designed to improve on previous laboratory limits by an order of magnitude, probing the effective neutrino mass with a sensitivity approaching 0.2 eV at 90% confidence via the kinematics of tritium beta decay. At the same time, KATRIN has the potential to scan for sterile neutrinos at eV and keV scales. After years of preparation, all major components are now on site and commissioning is underway. I will report on the current status of the experiment, including recent results and preparations for the introduction of tritium later this year. US participation in KATRIN is supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics under Award Number DE-FG02-97ER41020.

  7. Current Direct Neutrino Mass Experiments

    Directory of Open Access Journals (Sweden)

    G. Drexlin

    2013-01-01

    Full Text Available In this contribution, we review the status and perspectives of direct neutrino mass experiments, which investigate the kinematics of β-decays of specific isotopes (3H, 187Re, 163Ho to derive model-independent information on the averaged electron (antineutrino mass. After discussing the kinematics of β-decay and the determination of the neutrino mass, we give a brief overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and Troitsk experiments for 3H, cryobolometers for 187Re. We then describe the Karlsruhe Tritium Neutrino (KATRIN experiment currently under construction at Karlsruhe Institute of Technology, which will use the MAC-E-Filter principle to push the sensitivity down to a value of 200 meV (90% C.L.. To do so, many technological challenges have to be solved related to source intensity and stability, as well as precision energy analysis and low background rate close to the kinematic endpoint of tritium β-decay at 18.6 keV. We then review new approaches such as the MARE, ECHO, and Project8 experiments, which offer the promise to perform an independent measurement of the neutrino mass in the sub-eV region. Altogether, the novel methods developed in direct neutrino mass experiments will provide vital information on the absolute mass scale of neutrinos.

  8. Neutrino masses within the minimal supersymmetric Standard Model

    CERN Document Server

    Cvetic, M; Cvetic, Mirjam; Langacker, Paul

    1992-01-01

    We investigate the possibility of accommodating neutrino masses compatible with the MSW study of the Solar neutrino deficit within the minimal supersymmetric Standard Model. The ``gravity-induced'' seesaw mechanism based on an interplay of nonrenormalizable and renormalizable terms in the superpotential allows neutrino masses $m_\

  9. Mass Varying Neutrinos in Supernovae

    CERN Document Server

    Rossi-Torres, F; de Holanda, P C; Peres, O L G

    2010-01-01

    We study limits for the mass varying neutrino model, using constrains from supernova neutrinos placed by the r-process condition, $Y_e<0.5$. Also, we use this model in a supernova environment to study the regions of survival probability in the oscillation space parameter ($\\tan^2\\theta$ and $\\Delta m^2_0$), considering the channel $\

  10. Current Direct Neutrino Mass Experiments

    CERN Document Server

    Drexlin, G; Mertens, S; Weinheimer, C

    2013-01-01

    In this contribution we review the status and perspectives of direct neutrino mass experiments. These experiments investigate the kinematics of $\\beta$-decays of specific isotopes ($^3$H, $^{187}$Re, $^{163}$Ho) to derive model-independent information on the averaged electron (anti-) neutrino mass, which is formed by the incoherent sum of the neutrino mass eigenstates contributing to the electron neutrino. We first review the kinematics of $\\beta$-decay and the determination of the neutrino mass, before giving a brief overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and Troitsk experiments for $^3$H, cryo-bolometers for $^{187}$Re). We then describe the Karlsruhe Tritium Neutrino (KATRIN) experiment which is currently under construction at Karlsruhe Institute of Technology. The large-scale setup will use the MAC-E-Filter principle pioneered earlier to push the sensitivity down to a value of 200 meV(90% C.L.). KATRIN faces many technological challenges that have to be resolved with regar...

  11. Reactor mixing angle from hybrid neutrino masses

    CERN Document Server

    Sierra, D Aristizabal

    2014-01-01

    In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure with small deviations, as demanded by data. If neutrino masses originate from at least two different mechanisms, referred to as "hybrid neutrino masses", the experimentally observed structure naturally emerges provided one mechanism accounts for the dominant tribimaximal structure while the other is responsible for the deviations. We demonstrate the feasibility of this picture in a fairly model-independent way by using lepton-number-violating effective operators, whose structure we assume becomes dictated by an underlying $A_4$ flavor symmetry. We show that if a second mechanism is at work, the requirement of generating a reactor angle within its experimental range always fixes the solar and atmospheric angles in agreement with data, in contrast to the case where the deviations are induced by next-to-leading ...

  12. Neutrino masses from new generations

    CERN Document Server

    Aparici, Alberto; Rius, Nuria; Santamaria, Arcadi

    2011-01-01

    We reconsider the possibility that Majorana masses for the three known neutrinos are generated radiatively by the presence of a fourth generation and one right-handed neutrino with Yukawa couplings and a Majorana mass term. We find that the observed light neutrino mass hierarchy is not compatible with low energy universality bounds in this minimal scenario, but all present data can be accommodated with five generations and two right-handed neutrinos. Within this framework, we explore the parameter space regions which are currently allowed and could lead to observable effects in neutrinoless double beta decay, $\\mu - e$ conversion in nuclei and $\\mu \\rightarrow e \\gamma$ experiments. We also discuss the detection prospects at LHC.

  13. Neutrino mass from triton decay

    Science.gov (United States)

    Weinheimer, Christian

    2006-07-01

    Since the discovery of neutrino flavor oscillation in different fields and by many different experiments we believe that neutrinos have non-vanishing masses in contrast to their current description within the Standard Model of particle physics. However, the absolute values of the neutrino masses, which are as important for particle physics as they are for cosmology and astrophysics, cannot be determined by oscillation experiments alone. There are a few ways to determine the neutrino mass scale, but the only model-independent method is the investigation of the electron energy spectrum of a β decay near its endpoint with tritium being the ideal isotope for the classical spectrometer set-up. The tritium β decay experiments at Mainz and Troitsk have recently been finished. At Mainz all relevant systematic uncertainties have been investigated by dedicated experiments yielding an upper limit of m(ν)MAC-E-Filter type. The recent achievements in test experiments show, that this very challenging experiment is feasible.

  14. Small Neutrino Masses: Another Anthropic principle aspect?

    CERN Document Server

    Sivaram, C; O, Kiren

    2016-01-01

    This year's Physics Nobel prize for the discovery of neutrino oscillations which resolved the problem of the missing solar neutrinos and the atmospheric muon neutrinos implies that at least one of the three neutrino species has a tiny mass. The neutrino oscillations measure the mass difference squared, and the individual neutrino masses have yet to be accurately ascertained. Particle theory has so far not given a predictive picture for neutrino masses. Here we propose that the anthropic principle may be relevant, as it is frequently invoked to understand other aspects of the universe, including the precise values of fine structure constant or nuclear coupling constant or even the proton-electron mass ratio.

  15. Neutrino Mass Matrix with Approximate Flavor Symmetry

    CERN Document Server

    Riazuddin, M

    2003-01-01

    Phenomenological implications of neutrino oscillations implied by recent experimental data on pattern of neutrino mass matrix are disscussed. It is shown that it is possible to have a neutrino mass matrix which shows approximate flavor symmetry; the neutrino mass differences arise from flavor violation in off-diagonal Yukawa couplings. Two modest extensions of the standard model, which can embed the resulting neutrino mass matix have also been discussed.

  16. Models of neutrino masses and baryogenesis

    Indian Academy of Sciences (India)

    Utpal Sarkar

    2000-01-01

    Majorana masses of the neutrino implies lepton number violation and is intimately related to the lepton asymmetry of the universe, which gets related to the baryon asymmetry of the universe in the presence of the sphalerons during the electroweak phase transition. Assuming that the baryon asymmetry of the universe is generated before the electroweak phase transition, it is possible to discriminate different classes of models of neutrino masses. While see-saw mechanism and the triplet Higgs mechanism are preferred, the Zee-type radiative models and theR-parity breaking models requires additional inputs to generate baryon asymmetry of the universe during the electroweak phase transition.

  17. Small neutrino masses from gravitational θ -term

    Science.gov (United States)

    Dvali, Gia; Funcke, Lena

    2016-06-01

    We present how a neutrino condensate and small neutrino masses emerge from a topological formulation of gravitational anomaly. We first recapitulate how a gravitational θ -term leads to the emergence of a new bound neutrino state analogous to the η' meson of QCD. Then we show the consequent formation of a neutrino vacuum condensate, which effectively generates small neutrino masses. Afterwards we outline numerous phenomenological consequences of our neutrino mass generation model. The cosmological neutrino mass bound vanishes since we predict the neutrinos to be massless until the phase transition in the late Universe, T ˜meV . Coherent radiation of new light particles in the neutrino sector can be detected in prospective precision experiments. Deviations from an equal flavor rate due to enhanced neutrino decays in extraterrestrial neutrino fluxes can be observed in future IceCube data. These neutrino decays may also necessitate modified analyses of the original neutrino spectra of the supernova SN 1987A. The current cosmological neutrino background only consists of the lightest neutrinos, which, due to enhanced neutrino-neutrino interactions, either bind up, form a superfluid, or completely annihilate into massless bosons. Strongly coupled relic neutrinos could provide a contribution to cold dark matter in the late Universe, together with the new proposed particles and topological defects, which may have formed during neutrino condensation. These enhanced interactions could also be a source of relic neutrino clustering in our Galaxy, which possibly makes the overdense cosmic neutrino background detectable in the KATRIN experiment. The neutrino condensate provides a mass for the hypothetical B -L gauge boson, leading to a gravity-competing force detectable in short-distance measurements. Prospective measurements of the polarization intensities of gravitational waves can falsify our neutrino mass generation model.

  18. Neutrino mass generation with extra right-handed fields in a Dirac scenario via the type-I seesaw mechanism

    CERN Document Server

    Matute, Ernesto A

    2015-01-01

    An extension of the Standard Model (SM) is studied in which two right-handed (RH) neutrinos per generation are incorporated, but considering the hypothesis of the symmetry of lepton and quark contents in order to deprive the number of RH neutrinos of freedom, generate Dirac neutrinos and accommodate naturally tiny values for their masses. The high scale type-I seesaw regime is applied to the first, ordinary RH neutrino, whereas a low scale pseudo-Dirac scenario is used for the second, adulterant RH neutrino, implying that the first RH neutrino decouples at the high scale, while the second RH neutrino survives down to the low scale to pair off in a Dirac-like form with the corresponding left-handed (LH) neutrino. The small mass and couplings of this extra RH neutrino are explained by means of the statement of the symmetry of fermionic content, only regarded as a guideline to the natural choice of parameters since it is not a proper symmetry in the Lagrangian.

  19. Koide's Mass Formula for Neutrinos

    Science.gov (United States)

    Brannen, Carl

    2006-05-01

    We derive Koide's mass formula as an eigenvector equation. We show that to within current experimental error, the square roots of the masses of the charged leptons follow the simple equation (m^-n)^0.5 = μ1(1 + √2(δ1+ 2nπ/3)) where δ1 is the interesting number .22222204717(48) and μ1 is a constant. Next we generalize the Koide formula to the neutrinos by assuming that the square root of the mass of the smallest neutrino must be taken to be negative. Then masses of the simple form (m^0n)^0.5 = μ0(1 + √2(δ1+ π/12 + 2nπ/3)) where 3;μ0= 3^12 ;μ1, satisfy recent neutrino oscillation measurements close to the centers of the error bars. Finally, we discuss the preon model for the fermions that led to the above discovery.

  20. Neutrino mass without cosmic variance

    CERN Document Server

    LoVerde, Marilena

    2016-01-01

    Measuring the absolute scale of the neutrino masses is one of the most exciting opportunities available with near-term cosmological datasets. Two quantities that are sensitive to neutrino mass, scale-dependent halo bias $b(k)$ and the linear growth parameter $f(k)$ inferred from redshift-space distortions, can be measured without cosmic variance. Unlike the amplitude of the matter power spectrum, which always has a finite error, the error on $b(k)$ and $f(k)$ continues to decrease as the number density of tracers increases. This paper presents forecasts for statistics of galaxy and lensing fields that are sensitive to neutrino mass via $b(k)$ and $f(k)$. The constraints on neutrino mass from the auto- and cross-power spectra of spectroscopic and photometric galaxy samples are weakened by scale-dependent bias unless a very high density of tracers is available. In the high density limit, using multiple tracers allows cosmic-variance to be beaten and the forecasted errors on neutrino mass shrink dramatically. In...

  1. Theory of neutrino masses and mixing

    CERN Document Server

    Smirnov, Alexei Yu

    2014-01-01

    In spite of enormous experimental progress in determination of the neutrino parameters, theory of neutrino mass and mixing is still on the cross-roads. Guidelines could be (i) the connection between zero neutrino charges (and therefore a possibility to be Majorana particle), smallness of the neutrino mass and large lepton mixing, (ii) joint description of leptons and quarks, (iii) existence of the right handed (RH) neutrinos without special quantum numbers. Properties of the RH neutrinos and the UV completion of the seesaw may turn out to be the key to understand the neutrino mass and mixing. In view of the LHC results minimalistic scenarios like $\

  2. Dirac neutrino masses from generalized supersymmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Demir, D.A. [Izmir Institute of Technology, IZTECH, Izmir (Turkey). Dept. of Physics]|[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Everett, L.L. [University of Wisconsin, Madison, WI (United States), Dept. of Physics; Langacker, P. [Institute for Advanced Study, Princeton, NJ (United States). School of Natural Sciences

    2007-12-15

    We demonstrate that Dirac neutrino masses in the experimentally preferred range are generated within supersymmetric gauge extensions of the Standard Model with a generalized supersymmetry breaking sector. If the usual superpotential Yukawa couplings are forbidden by the additional gauge symmetry (such as a U(1){sup '}), effective Dirac mass terms involving the ''wrong Higgs'' field can arise either at tree level due to hard supersymmetry breaking fermion Yukawa couplings, or at one-loop due to nonanalytic or ''nonholomorphic'' soft supersymmetry breaking trilinear scalar couplings. As both of these operators are naturally suppressed in generic models of supersymmetry breaking, the resulting neutrino masses are naturally in the sub-eV range. The neutrino magnetic and electric dipole moments resulting from the radiative mechanism also vanish at one-loop order. (orig.)

  3. Neutrino Masses and Oscillations

    CERN Document Server

    CERN. Geneva. Audiovisual Unit; Treille, Daniel

    2002-01-01

    This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos.

  4. Neutrino masses From fantasy to facts

    CERN Document Server

    Valle, José W F

    1999-01-01

    Theory suggests the existence of neutrino masses, but little more. Facts are coming close to reveal our fantasy: solar and atmospheric neutrino data strongly indicate the need for neutrino conversions, while LSND provides an intriguing hint. The simplest ways to reconcile these data in terms of neutrino oscillations invoke a light sterile neutrino in addition to the three active ones. Out of the four neutrinos, two are maximally-mixed and lie at the LSND scale, while the others are at the solar mass scale. These schemes can be distinguished at neutral-current-sensitive solar & atmospheric neutrino experiments. I discuss the simplest theoretical scenarios, where the lightness of the sterile neutrino, the nearly maximal atmospheric neutrino mixing, and the generation of $\\Delta {m^2}_\\odot$ & $\\Delta {m^2}_{atm}$ all follow naturally from the assumed lepton-number symmetry and its breaking. Although the most likely interpretation of the present data is in terms of neutrino-mass-induced oscillations, one...

  5. Hierarchical neutrino masses and mixing in flipped-SU(5)

    Energy Technology Data Exchange (ETDEWEB)

    Rizos, J. [Physics Department, University of Ioannina, 45110 Ioannina (Greece); Tamvakis, K., E-mail: tamvakis@uoi.g [Physics Department, University of Ioannina, 45110 Ioannina (Greece); Physics Department, CERN, CH-1211, Geneva 23 (Switzerland)

    2010-02-22

    We consider the problem of neutrino masses and mixing in the framework of flipped SU(5). The right-handed neutrino mass, generated through the operation of a seesaw mechanism by a sector of gauge singlets, leads naturally, at a subsequent level, to the standard seesaw mechanism resulting into three light neutrino states with masses of the desired phenomenological order of magnitude. In this framework we study simple Ansaetze for the singlet couplings for which hierarchical neutrino masses emerge naturally as lambda{sup n}:lambda:1 or lambda{sup n}:lambda{sup 2}:1, parametrized in terms of the Cabbibo parameter. The resulting neutrino mixing matrices are characterized by a hierarchical structure, in which theta{sub 13} is always predicted to be the smallest. Finally, we discuss a possible factorized parametrization of the neutrino mass that, in addition to Cabbibo mixing, encodes also mixing due to the singlet sector.

  6. Neutrino Mass Seesaw Version 3: Recent Developments

    CERN Document Server

    Ma, Ernest

    2009-01-01

    The origin of neutrino mass is usually attributed to a seesaw mechanism, either through a heavy Majorana fermion singlet (version 1) or a heavy scalar triplet (version 2). Recently, the idea of using a heavy Majorana fermion triplet (version 3) has gained some attention. This is a review of the basic idea involved, its U(1) gauge extension, and some recent developments.

  7. Direct measurements of neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Holzschuh, E. [Zurich Univ. (Switzerland). Inst. fuer Physik

    1996-11-01

    The direct measurements have so far given no indication for a nonzero (positive) mass of any of the three known neutrinos. The experiments measuring the tau and the muon neutrino are good shape. The tritium experiments are in an unfortunate situation. It is unclear to me whether the problems are experimental or theoretical or a combination of both. The electronic final states distribution have been calculated, but the results have never been tested experimentally. The most important question to be answered is about the validity of the sudden approximation. (author) 9 figs., 2 tabs., 16 refs.

  8. Neutrino Mass and Flavour Models

    CERN Document Server

    King, Stephen F

    2009-01-01

    We survey some of the recent promising developments in the search for the theory behind neutrino mass and tri-bimaximal mixing, and indeed all fermion masses and mixing. We focus in particular on models with discrete family symmetry and unification, and show how such models can also solve the SUSY flavour and CP problems. We also discuss the theoretical implications of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

  9. Cosmology in Mirror Twin Higgs and Neutrino Masses

    CERN Document Server

    Chacko, Zackaria; Fox, Patrick J; Harnik, Roni

    2016-01-01

    We explore a simple solution to the cosmological challenges of the original Mirror Twin Higgs (MTH) model that leads to interesting implications for experiment. We consider theories in which both the standard model and mirror neutrinos acquire masses through the familiar seesaw mechanism, but with a low right-handed neutrino mass scale of order a few GeV. In these $\

  10. Neutrino Masses, where do we stand?

    CERN Document Server

    Valle, José W F

    1999-01-01

    I review the status of neutrino physics post-Neutrino~98, including the implications of solar and atmospheric neutrino data, which strongly indicate nonzero neutrino masses. LSND and the possible role of neutrinos as hot dark matter (HDM) are also mentioned. The simplest schemes proposed to reconcile these requirements invoke a light sterile neutrino in addition to the three active ones, two of them at the MSW scale and the other two maximally-mixed neutrinos at the HDM/LSND scale. In the simplest theory the latter scale arises at one-loop, while the solar and atmospheric parameters $\\Delta {m^2}_\\odot$ & neutrino, the nearly maximal atmospheric neutrino mixing, and the generation of lepton-number symmetry and its breaking. These two basic schemes can be distinguished at future solar & atmospheric neutrino experiments and have different cosmological implications.

  11. Neutrino masses and mixing in supersymmetric theories

    Indian Academy of Sciences (India)

    Sudhir K Vempati

    2000-07-01

    It has been known for sometime that supersymmetric theories with -parity violation provide a natural framework where small neutrino masses can be generated. We discuss neutrino masses and mixing in these theories in the presence of trilinear lepton number violating couplings. It will be shown that simultaneous solutions to solar and atmospheric neutrino problems can be realized in these models.

  12. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    Srubabati Goswami

    2000-01-01

    In this article I review the constraints on neutrino mass and mixing coming from type-II supernovae. The bounds obtained on these parameters from shock reheating, -process nucleosynthesis and from SN1987A are discussed. Given the current constraints on neutrino mass and mixing the effect of oscillations of neutrinos from a nearby supernova explosion in future detectors will also be discussed.

  13. Solar mass-varying neutrino oscillations.

    Science.gov (United States)

    Barger, V; Huber, Patrick; Marfatia, Danny

    2005-11-18

    We propose that the solar neutrino deficit may be due to oscillations of mass-varying neutrinos (MaVaNs). This scenario elucidates solar neutrino data beautifully while remaining comfortably compatible with atmospheric neutrino and K2K data and with reactor antineutrino data at short and long baselines (from CHOOZ and KamLAND). We find that the survival probability of solar MaVaNs is independent of how the suppression of neutrino mass caused by the acceleron-matter couplings varies with density. Measurements of MeV and lower energy solar neutrinos will provide a rigorous test of the idea.

  14. Neutrino Mass from a Higher-Dimensional Operator

    Institute of Scientific and Technical Information of China (English)

    NING Guo-Zhu; WU Yuan-Bin

    2011-01-01

    We calculate the neutrino mass induced at one loop in the cascade seesaw mechanism. The ratio between the two neutrino masses, which are respectively generated from an operator of mass dimension (3 + An) occurring at one loop and an operator of dimension (5 + An) at tree JeveJ, is also given. Detailed studies show that a relatively low new physics scale could accommodate the tiny neutrino mass of desired order without demanding small couplings. We also find that the ratio will reach order one when the new physics scale is higher than several TeV and n is small. In this case, the contribution to neutrino mass from higher order quantum effects becomes important and cannot be ignored.%@@ We calculate the neutrino mass induced at one loop in the cascade seesaw mechanism.The ratio between the two neutrino masses, which are respectively generated from an operator of mass dimension (3 + 4n) occurring at one loop and an operator of dimension (5 + 4n) at tree level, is also given.Detailed studies show that a relatively low new physics scale could accommodate the tiny neutrino mass of desired order without demanding small couplings.We also find that the ratio will reach order one when the new physics scale is higher than several TeV and n is small In this case, the contribution to neutrino mass from higher order quantum effects becomes important and cannot be ignored.

  15. General Neutrino Mass Matrix Patterns and Its Underlying Family Symmetries

    CERN Document Server

    Damanik, Asan; Anggraita, Pramudita; Muslim,

    2014-01-01

    Baseon on current experimental results, such as neutrino oscillations and the neutrinoless double beta decays (i.e. data from Super Kamiokande, KamLAND, SNO, etc.), the neutrino mixing matrix can be adequately determined. Though there are still certain parameters that have possibility limits, but based on the current experimental results it is possible to construct a general form of neutrino mass matrix. Starting from this general form of the neutrino mass matrix we put certain conditions in the context of the seesaw mechanism model to determine the possible pattern of the neutrino mass matrix that has a texture zero. From the obtained neutrino mass matrix pattern, there are three class of patterns, where two of the class are known to be realized in literature by the underlying family symmetries of the $D_{4}$ and $A_{4}$ groups, the dihedral and tetrahedral symmetry groups.

  16. Radiative neutrino mass model with degenerate right-handed neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwase, Shoichi; Suematsu, Daijiro [Kanazawa University, Institute for Theoretical Physics, Kanazawa (Japan)

    2016-03-15

    The radiative neutrino mass model can relate neutrino masses and dark matter at a TeV scale. If we apply this model to thermal leptogenesis, we need to consider resonant leptogenesis at that scale. It requires both finely degenerate masses for the right-handed neutrinos and a tiny neutrino Yukawa coupling. We propose an extension of the model with a U(1) gauge symmetry, in which these conditions are shown to be simultaneously realized through a TeV scale symmetry breaking. Moreover, this extension can bring about a small quartic scalar coupling between the Higgs doublet scalar and an inert doublet scalar which characterizes the radiative neutrino mass generation. It also is the origin of the Z{sub 2} symmetry which guarantees the stability of dark matter. Several assumptions which are independently supposed in the original model are closely connected through this extension. (orig.)

  17. Radiative neutrino mass model with degenerate right-handed neutrinos

    CERN Document Server

    Kashiwase, Shoichi

    2015-01-01

    The radiative neutrino mass model can relate neutrino masses and dark matter at a TeV scale. If we apply this model to thermal leptogenesis, we need to consider resonant leptogenesis at that scale. It requires both finely degenerate masses for right-handed neutrinos and a tiny neutrino Yukawa coupling. We propose an extension of the model with a U(1) gauge symmetry, in which these conditions are shown to be simultaneously realized through a TeV scale symmetry breaking. Moreover, this extension can bring about a small quartic scalar coupling between the Higgs doublet scalar and an inert doublet scalar which characterizes the radiative neutrino mass generation. It also gives the origin of $Z_2$ symmetry which guarantees the stability of dark matter. Several assumptions which are independently supposed in the original model are closely connected through this extension.

  18. New mechanism for Type-II seesaw dominance in SO(10) with low-mass Z', RH neutrinos, and verifiable LFV, LNV and proton decay

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, Bidyut Prava; Parida, Mina Ketan [Siksha ' ' O' ' Anusandhan University, Centre of Excellence in Theoretical and Mathematical Sciences, Bhubaneswar, Odisha (India)

    2015-05-15

    The dominance of Type-II seesaw mechanism for the neutrino masses has attracted considerable attention because of a number of advantages. We show a novel approach to achieve Type-II seesaw dominance in nonsupersymmetric SO(10) grand unification where a low-mass Z' boson and specific patterns of right-handed neutrino masses are predicted within the accessible energy range of the Large Hadron Collider. In spite of the high value of the seesaw scale, M{sub Δ{sub L}} ≅ 10{sup 8}-10{sup 9} GeV, the model predicts new dominant contributions to neutrino-less double beta decay in the W{sub L}-W{sub L} channel close to the current experimental limits via exchanges of heavier singlet fermions used as essential ingredients of this model even when the light active neutrino masses are normally hierarchical or invertedly hierarchical. We obtain upper bounds on the lightest sterile neutrino mass m{sub s} neutrino masses, respectively. The underlying nonunitarity effects lead to lepton flavour violating decay branching ratios within the reach of ongoing or planned experiments and the leptonic CP-violation parameter nearly two order larger than the quark sector. Some of the predicted values on the proton lifetime for p → e{sup +}π{sup 0} are found to be within the currently accessible search limits. Other aspects of model applications including leptogenesis etc. are briefly indicated. (orig.)

  19. Possible scenario for MaVaN's as the only neutrino flavor conversion mechanism in the Sun

    CERN Document Server

    de Holanda, Pedro Cunha

    2008-01-01

    Mass Varying neutrino mechanisms were proposed to link the neutrino mass scale with dark energy, addressing the coincidence problem. In some scenarios this mass can present a dependence on the baryonic density felt by neutrinos, creating an effective neutrino mass that depends both on the neutrino and baryonic densities. In this article we investigate the possibility that a neutrino effective mass is the only flavour conversion mechanism acting in neutrino oscillation experiments. We present a parameterization on the environmental effects on neutrino mass that produces the right flavour conversion probabilities for solar and terrestrial neutrinos experiments.

  20. Neutrino oscillations and the seesaw origin of neutrino mass

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, O.G., E-mail: omr@fis.cinvestav.mx [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000 Mexico, Distrito Federal (Mexico); Valle, J.W.F. [AHEP Group, Institut de Física Corpuscular – C.S.I.C./Universitat de València, Parc Cientific de Paterna, C/Catedratico José Beltrán, 2, E-46980 Paterna (València) (Spain)

    2016-07-15

    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.

  1. Neutrino oscillations and the seesaw origin of neutrino mass

    Science.gov (United States)

    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.

  2. Neutrino masses in astrophysics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Raffelt, G.G. [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    1996-11-01

    Astrophysical and cosmological arguments and observations give us the most restrictive constraints on neutrino masses, electromagnetic couplings, and other properties. Conversely, massive neutrinos would contribute to the cosmic dark-matter density and would play an important role for the formation of structure in the universe. Neutrino oscillations may well solve the solar neutrino problem, and can have a significant impact on supernova physics. (author) 14 figs., tabs., 33 refs.

  3. Implications of new generations on neutrino masses

    CERN Document Server

    Aparici, A; Rius, N; Santamaria, A

    2011-01-01

    We explore the possible implications that new families, that are being searched for at the LHC, would have on neutrino masses. In particular, we have explored the possibility that the smallness of the observed neutrino masses is naturally understood in a modified version of the Standard Model (SM) with complete extra generations of fermions, i.e., that have right-handed neutrinos, in which neutrino masses are generated at two loops. With one extra family it is not possible to fit the observed spectrum of masses and mixings. However, the radiative mass generated provides an important constraint in these kind of models, so the neutrino masses do not exceed their cosmological bound. Within the context of two extra families, we analyse the allowed parameter space and the possible phenomenological signals. Contribution to NUFACT 11, XIIIth International Workshop on Neutrino Factories, Super beams and Beta beams, 1-6 August 2011, CERN and University of Geneva (Submitted to IOP conference series).

  4. A predictive scheme for neutrino masses

    CERN Document Server

    Joshipura, A S; Joshipura, Anjan S.; Rindani, Saurabh D.

    2002-01-01

    The solar and atmospheric data and possibly large value for the effective neutrino mass in neutrinoless double beta decay experiment together indicate that all the three neutrinos are nearly degenerate. A verifiable texture for the neutrino mass matrix is proposed to accommodate these results. This texture allows almost degenerate neutrino masses two of which are exactly degenerate at tree level. The standard model radiative corrections lift this degeneracy and account for the solar deficit. The solar scale is correlated with the effective neutrino mass $m_{ee}$ probed in neutrinoless double beta decay experiments. The model can accommodate a large value of O(eV) for $m_{ee}$. Six observables corresponding to three neutrino masses and three mixing angles are determined in terms of only three unknown parameters within the proposed texture.

  5. Neutrino masses from an approximate mixing matrix with $\\theta_{13}\

    CERN Document Server

    Damanik, Asan

    2016-01-01

    An approximate neutrino mixing matrix is formutated by using the standard neutrino mixing matrix as a basis and experimental data of neutrino oscillations as inputs. By using the resulted approximate neutrino mixing matrix to proceed the neutrino mass matrix and constraining the resulted neutrino mass matrix with zero texture: $M_{\

  6. Probing the Absolute Mass Scale of Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Prof. Joseph A. Formaggio

    2011-10-12

    The experimental efforts of the Neutrino Physics Group at MIT center primarily around the exploration of neutrino mass and its significance within the context of nuclear physics, particle physics, and cosmology. The group has played a prominent role in the Sudbury Neutrino Observatory, a neutrino experiment dedicated to measure neutrino oscillations from 8B neutrinos created in the sun. The group is now focusing its efforts in the measurement of the neutrino mass directly via the use of tritium beta decay. The MIT group has primary responsibilities in the Karlsruhe Tritium Neutrino mass experiment, expected to begin data taking by 2013. Specifically, the MIT group is responsible for the design and development of the global Monte Carlo framework to be used by the KATRIN collaboration, as well as responsibilities directly associated with the construction of the focal plane detector. In addition, the MIT group is sponsoring a new research endeavor for neutrino mass measurements, known as Project 8, to push beyond the limitations of current neutrino mass experiments.

  7. Neutrino mass and oscillation: An introductory review

    Indian Academy of Sciences (India)

    D P Roy

    2000-01-01

    After a brief introduction to neutrino mass via the see-saw model I discuss neutrinomixing and oscillation, first in vacuum and then its matter enhancement. Then the solar and atmospheric neutrino oscillation data are briefly reviewed. Finally I discuss the problem of reconciling hierarchical neutrino masses with at least one large mixing, as implied by these data. A minimal see-saw model for reconciling the two is discussed.

  8. Neutrinoless double beta decay and neutrino mass

    Science.gov (United States)

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

    2016-11-01

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

  9. Models for neutrino mass with discrete symmetries

    Science.gov (United States)

    Morisi, S.

    2011-08-01

    Discrete non-abelian flavor symmetries give in a natural way tri-bimaximal (TBM) mixing as showed in a prototype model. However neutrino mass matrix pattern may be very different from the tri-bimaximal one if small deviations of TBM will be observed. We give the result of a model independent analysis for TBM neutrino mass pattern.

  10. Models for neutrino mass with discrete symmetries

    CERN Document Server

    Morisi, S

    2010-01-01

    Discrete non-abelian flavor symmetries give in a natural way tri-bimaximal (TBM) mixing as showed in a prototype model. However neutrino mass matrix pattern may be very different from the tri-bimaximal one if small deviations of TBM will be observed. We give the result of a model independent analysis for TBM neutrino mass pattern.

  11. Neutrino masses twenty-five years later

    CERN Document Server

    Valle, José W F

    2003-01-01

    The discovery of neutrino mass marks a turning point in elementary particle physics, with important implications for nuclear and astroparticle physics. Here I give a brief update, where I summarize the current status of three-neutrino oscillation parameters from current solar, atmospheric, reactor and accelerator neutrino data, discuss the case for sterile neutrinos and LSND, and also the importance of tritium and double beta decay experiments probing the absolute scale of neutrino mass. In this opininated look at the present of neutrino physics, I keep an eye in the future, and a perspective of the past, taking the oportunity to highlight Joe Schechter's pioneering contribution, which I have had the fortune to share, as his PhD student back in the early eighties.

  12. Neutrino Mass Matrix Predicted From Symmetric Texture

    CERN Document Server

    Bando, M; Bando, Masako; Obara, Midori

    2003-01-01

    Within the framework of grand unified theories, we make full analysis of symmetric texture to see if such texture can reproduce large neutrino mixings, which have recently been confirmed by the observed solar and atmospheric neutrino oscillation experiments. It is found that so-called symmetric texture with anomalous U(1) family symmetry with Froggatt-Nielsen mechanism does not provide a natural explanation of two large mixing angles. On the contrary we should adopt "zero texture" which have been extensively studied by many authors and only this scenario can reproduce two large mixing angles naturally. Under such "zero texture" with minimal symmetric Majorana matrix, all the neutrino masses and mixing angles, 6 quantities, are expressed in terms of up-quark masses, $m_t,m_c,m_u$ with two adjustable parameters. This provides interesting relations among neutrio mixing angles, $\\tan^2 2\\theta_{12} \\simeq \\frac{144m_c}{m_t} \\tan^2 2\\theta_{23} \\cos^2 \\theta_{23}, \\quad \\sin^2 \\theta_{13} \\simeq \\frac{4m_c}{m_t}\\s...

  13. Neutrino Mass and Mixing with Discrete Symmetry

    CERN Document Server

    King, Stephen F

    2013-01-01

    This is a review article about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of seesaw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mec...

  14. Yukawa couplings and seesaw neutrino masses in noncommutative gauge theory

    Energy Technology Data Exchange (ETDEWEB)

    Horvat, Raul [Physics Division, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia); Ilakovac, Amon [Faculty of Science, University of Zagreb, Bijenicka 32, Zagreb (Croatia); Schupp, Peter [Center for Mathematics, Modeling and Computing, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany); Trampetic, Josip [Physics Division, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia); Max-Planck-Institut fuer Physik, Werner-Heisenberg-Institut, Foehringer Ring 6, D-80805 Muenchen (Germany); You, Jiangyang, E-mail: Jiangyang.You@irb.hr [Physics Division, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia)

    2012-09-10

    We consider Yukawa couplings in a {theta}-exact approach to noncommutative gauge field theory and show that both Dirac and singlet Majorana neutrino mass terms can be consistently accommodated. This shows that in fact the whole neutrino-mass extended standard model on noncommutative spacetime can be formulated in the new nonperturbative (in {theta}) approach which eliminates the previous restriction of Seiberg-Witten map based theories to low-energy phenomena. Spacetime noncommutativity induced couplings between neutrinos and photons as well as Z-bosons appear quite naturally in the model. We derive relevant Feynman rules for the type I seesaw mechanism.

  15. Constraints on Neutrino Mass from Galaxy Surveys

    Science.gov (United States)

    Cuesta, A. J.; Niro, V.; Verde, L.

    2017-03-01

    Modern large-scale galaxy surveys, combined with measurements of the cosmic microwave background, have managed to constrain the sum of neutrino masses to an order of magnitude below the limit placed by laboratory experiments. We discuss the signature of massive neutrinos in the distribution of galaxies and the current state of the art of neutrino mass constraints, focusing on parameter degeneracies that reveal how we can improve current constraints with next-generation galaxy surveys. We also comment on how the near future cosmology experiments are an opportunity for the first measurement of the value of the sum of neutrino masses, or alternatively, to find profound implications for neutrino physics extensions beyond the Standard Model.

  16. Neutrino masses and ordering via multimessenger astronomy

    DEFF Research Database (Denmark)

    Langæble, Kasper; Meroni, Aurora; Sannino, Francesco

    2016-01-01

    We define the theoretical framework and deduce the conditions under which multi-messenger astronomy can provide useful information about neutrino masses and their ordering. The framework uses time differences between the arrival of neutrinos and the other light messenger, i.e. the graviton, emitted...

  17. Cosmology and the neutrino mass ordering

    DEFF Research Database (Denmark)

    Hannestad, Steen; Schwetz, Thomas

    2016-01-01

    We propose a simple method to quantify a possible exclusion of the inverted neutrino mass ordering from cosmological bounds on the sum of the neutrino masses. The method is based on Bayesian inference and allows for a calculation of the posterior odds of normal versus inverted ordering. We apply...... the method for a specific set of current data from Planck CMB data and large-scale structure surveys, providing an upper bound on the sum of neutrino masses of 0.14 eV at 95% CL. With this analysis we obtain posterior odds for normal versus inverted ordering of about 2:1. If cosmological data is combined...

  18. Can New Generations Explain Neutrino Masses?

    CERN Document Server

    Aparici, A; Rius, N; Santamaria, A

    2011-01-01

    In this talk we explore the possibility that the smallness of the observed neutrino masses is naturally understood in a modified version of the standard model with N extra generations of fermions and N right-handed neutrinos, in which light neutrino masses are generated at two loops. We find that with N = 1 it is not possible to fit the observed spectrum of masses and mixings while with N = 2 it is. Within this extension, we analyse the parameters which are allowed and the possible phenomenological signals of the model in future experiments. Contribution to the proceedings of Les Rencontres de Moriond EW 2011, Young Scientist Forum.

  19. Present Aspects and Future Prospects of Neutrino Mass and Oscillation

    CERN Document Server

    Ghosh, Monojit

    2016-01-01

    Neutrinos are neutral, spin-$\\frac{1}{2}$ particles which undergo only weak interactions. The experimentally observed phenomenon of neutrino oscillation establishes the fact that neutrinos are massive and there is mixing between different neutrino flavours. This constitutes the first unambiguous hint towards the physics Beyond Standard Model (BSM). In the BSM theories, the neutrino mass terms in the Lagrangian lead to the non-diagonal neutrino mass matrix in the flavour basis which depends on neutrino mass and mixing parameters. Thus knowledge of the neutrino oscillation parameters and understanding the underlying symmetries of the neutrino mass matrix are very important as they can give an insight to the new physics beyond Standard Model. Therefore the measurement of different oscillation parameters and studying the structure of the neutrino mass matrix are some of the main goals in neutrino physics at present. In this thesis we have studied the potential of present/future neutrino oscillation experiments an...

  20. Neutrino mass from neutrinophilic Higgs and leptogenesis

    CERN Document Server

    Haba, Naoyuki; Yamaguchi, Yuya

    2014-01-01

    In a class of two Higgs doublet model, where one Higgs doublet generates masses of quarks and charged leptons whereas the other Higgs doublet with a tiny vacuum expectation value (VEV) generates neutrino Dirac masses, smallness of neutrino masses might be understand as the consequence of the small second Higgs VEV. In this framework, thermal leptogenesis scenarios work well at low energy scale and have several advantages as follows. Under the assumption of hierarchical right-handed neutrino masses, the lightest right-handed neutrino can be as light as ${\\cal O}(10^2)$ TeV.The required degeneracy for successful resonant leptogenesis also can be significantly reduced as small as ${\\cal O}(10^4)$. Availability of low scale thermal leptogenesis provides a novel solution to gravitino problem in supergravity models.

  1. Predictive Model of Radiative Neutrino Masses

    CERN Document Server

    Babu, K S

    2013-01-01

    We present a simple and predictive model of radiative neutrino masses. It is a special case of the Zee model which introduces two Higgs doublets and a charged singlet. We impose a family-dependent Z_4 symmetry acting on the leptons, which reduces the number of parameters describing neutrino oscillations to four. A variety of predictions follow: The hierarchy of neutrino masses must be inverted; the lightest neutrino mass is extremely small and calculable; one of the neutrino mixing angles is determined in terms of the other two; the phase parameters take CP-conserving values with \\delta_{CP} = \\pi; and the effective mass in neutrinoless double beta decay lies in a narrow range, m_{\\beta \\beta} = (17.6 - 18.5) meV. The ratio of vacuum expectation values of the two Higgs doublets, tan\\beta, is determined to be either 1.9 or 0.19 from neutrino oscillation data. Flavor-conserving and flavor-changing couplings of the Higgs doublets are also determined from neutrino data. The non-standard neutral Higgs bosons, if t...

  2. Cosmological and astrophysical neutrino mass measurements

    DEFF Research Database (Denmark)

    Abazajian, K.N.; Calabrese, E.; Cooray, A.

    2011-01-01

    Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach.......Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach....

  3. Pathways to Naturally Small Dirac Neutrino Masses

    CERN Document Server

    Ma, Ernest

    2016-01-01

    If neutrinos are truly Dirac fermions, the smallness of their masses may still be natural if certain symmetries exist beyond those of the standard model of quarks and leptons. We perform a systematic study of how this may occur at tree level and in one loop. We also propose a scotogenic version of the left-right gauge model with naturally small Dirac neutrino masses in one loop.

  4. Splitting Neutrino masses and Showering into Sky

    Science.gov (United States)

    Fargion, D.; D'Armiento, D.; Lanciano, O.; Oliva, P.; Iacobelli, M.; de Sanctis Lucentini, P. G.; Grossi, M.; de Santis, M.

    2007-06-01

    Neutrino masses might be as light as a few time the atmospheric neutrino mass splitting. The relic cosmic neutrinos may cluster in wide Dark Hot Local Group Halo. High Energy ZeV cosmic neutrinos (in Z-Showering model) might hit relic ones at each mass in different resonance energies in our nearby Universe. This non-degenerated density and energy must split UHE Z-boson secondaries (in Z-Burst model) leading to multi injection of UHECR nucleons within future extreme AUGER energy. Secondaries of Z-Burst as neutral gamma, below a few tens EeV are better surviving local GZK cut-off and they might explain recent Hires BL-Lac UHECR correlations at small angles. A different high energy resonance must lead to Glashow's anti-neutrino showers while hitting electrons in matter. In water and ice it leads to isotropic light explosions. In air, Glashow's anti-neutrino showers lead to collimated and directional air-showers offering a new Neutrino Astronomy. Because of neutrino flavor mixing, astrophysical energetic tau neutrino above tens GeV must arise over atmospheric background. At TeV range is difficult to disentangle tau neutrinos from other atmospheric flavors. At greater energy around PeV, Tau escaping mountains and Earth and decaying in flight are effectively showering in air sky. These Horizontal showering is splitting by geomagnetic field in forked shapes. Such air-showers secondaries release amplified and beamed gamma bursts (like observed TGF), made also by muon and electron pair bundles, with their accompanying rich Cherenkov flashes. Also planet's largest (Saturn, Jupiter) atmosphere limbs offer an ideal screen for UHE GZK and Z-burst tau neutrino, because their largest sizes. Titan thick atmosphere and small radius are optimal for discovering up-going resonant Glashow resonant anti-neutrino electron showers. Detection from Earth of Tau, anti-Tau, anti-electron neutrino induced Air-showers by twin Magic Telescopes on top mountains, or space based detection on

  5. Flavour Dependent Gauged Radiative Neutrino Mass Model

    CERN Document Server

    Baek, Seungwon; Yagyu, Kei

    2015-01-01

    We propose a one-loop induced radiative neutrino mass model with anomaly free flavour dependent gauge symmetry: $\\mu$ minus $\\tau$ symmetry $U(1)_{\\mu-\\tau}$. A neutrino mass matrix satisfying current experimental data can be obtained by introducing a weak isospin singlet scalar boson that breaks $U(1)_{\\mu-\\tau}$ symmetry, an inert doublet scalar field, and three right-handed neutrinos in addition to the fields in the standard model. We find that a characteristic structure appears in the neutrino mass matrix: two-zero texture form which predicts three non-zero neutrino masses and three non-zero CP-phases which can be determined five well measured experimental inputs of two squared mass differences and three mixing angles. Furthermore, it is clarified that only the inverted mass hierarchy is allowed in our model. In a favored parameter set from the neutrino sector, the discrepancy in the muon anomalous magnetic moment between the experimental data and the the standard model prediction can be explained by the ...

  6. Cosmological impact of the neutrino rest mass

    Energy Technology Data Exchange (ETDEWEB)

    Doroshkevich, A.G. (Akademiia Nauk SSSR, Institut Prikladnoi Matematiki, Moscow, USSR); Khlopov, M.Iu. (Akademiia Nauk SSSR, Institut Kosmicheskikh Issledovanii, Moscow, USSR); Suniaev, R.A. (Eotvos Lorand Tudomanyegyetem, Budapest, Hungary); Szalay, A.S. (California, University, Berkeley, CA)

    1981-12-29

    The consequences of nonzero neutrino mass for several outstanding problems in astrophysics are described and discussed. The universe would in this case be gravitationally dominated by neutrinos, with all dynamical properties being determined by their mass density of approximately 1.0, while baryons may have a density of about 0.03, in agreement with observations of luminous matter and with the implications of the observed deuterium abundance. Because the growth of baryon fluctuations is accelerated by the neutrinos after recombination, background radiation temperature fluctuations may remain as small as less than 0.001, again in agreement with observations. The perturbations of neutrinos are adiabatic, and the damping of these fluctuations in the linear regime determines a characteristic mass which is typical of superclusters. A cellular structure with filaments is predicted on the supercluster scale, with characteristic separations on the order of 15-60 Mpc.

  7. Small Neutrino Masses from Gravitational $\\theta$-Term

    CERN Document Server

    Dvali, Gia

    2016-01-01

    We present how a neutrino condensate and small neutrino masses emerge from a topological formulation of gravitational anomaly. We first recapitulate how a gravitational $\\theta$-term leads to the emergence of a new bound neutrino state analogous to the $\\eta'$ meson of QCD. Then we show the consequent formation of a neutrino vacuum condensate which effectively generates small neutrino masses. Afterwards we outline numerous phenomenological consequences of our model. The cosmological neutrino mass bound vanishes since we predict the neutrinos to be massless until the very late universe, $T\\sim {\\rm meV}$. Coherent radiation of new light particles in the neutrino sector could be detected in future precision experiments. The current cosmological neutrino background consists only of the lightest neutrinos which are either bound up, form a superfluid, or completely annihilate into massless bosons. The deviations from an equal flavor rate due to enhanced neutrino decays in extraterrestrial neutrino fluxes can be ob...

  8. Hierarchical majorana neutrinos from democratic mass matrices

    Science.gov (United States)

    Yang, Masaki J. S.

    2016-09-01

    In this paper, we obtain the light neutrino masses and mixings consistent with the experiments, in the democratic texture approach. The essential ansatz is that νRi are assumed to transform as "right-handed fields" 2R +1R under the S3L ×S3R symmetry. The symmetry breaking terms are assumed to be diagonal and hierarchical. This setup only allows the normal hierarchy of the neutrino mass, and excludes both of inverted hierarchical and degenerated neutrinos. Although the neutrino sector has nine free parameters, several predictions are obtained at the leading order. When we neglect the smallest parameters ζν and ζR, all components of the mixing matrix UPMNS are expressed by the masses of light neutrinos and charged leptons. From the consistency between predicted and observed UPMNS, we obtain the lightest neutrino masses m1 = (1.1 → 1.4) meV, and the effective mass for the double beta decay ≃ 4.5 meV.

  9. Common Origin of Neutrino Mass, Dark Matter and Dirac Leptogenesis

    CERN Document Server

    Borah, Debasish

    2016-01-01

    We study the possibility of generating tiny Dirac neutrino masses at one loop level through the \\textit{scotogenic} mechanism such that one of the particles going inside the loop can be a stable cold dark matter (DM) candidate. Majorana mass terms of singlet fermions as well as tree level Dirac neutrino masses are prevented by incorporating the presence of additional discrete symmetries in a minimal fashion, which also guarantee the stability of the dark matter candidate. Due to the absence of total lepton number violation, the observed baryon asymmetry of the Universe is generated through the mechanism of Dirac leptogenesis where an equal and opposite amount of leptonic asymmetry is generated in the left and right handed sectors which are prevented from equilibration due to tiny Dirac Yukawa couplings. Dark matter relic abundance is generated through its usual freeze-out at a temperature much below the scale of leptogenesis. We constrain the relevant parameter space from neutrino mass, baryon asymmetry, Plan...

  10. Dynamical seesaw mechanism for Dirac neutrinos

    Directory of Open Access Journals (Sweden)

    José W.F. Valle

    2016-04-01

    Full Text Available So far we have not been able to establish that, as theoretically expected, neutrinos are their own anti-particles. Here we propose a dynamical way to account for the Dirac nature of neutrinos and the smallness of their mass in terms of a new variant of the seesaw paradigm in which the energy scale of neutrino mass generation could be accessible to the current LHC experiments.

  11. Phenomenological analysis of properties of the RH Majorana neutrino in the seesaw mechanism

    CERN Document Server

    Pan, H; Pan, Haijun

    2002-01-01

    As an extension of our previous work in the seesaw mechanism, we analyze the influence of $U_{e3}$ on the properties (masses and mixing) of the RH Majorana neutrinos in three flavors. The quasidegenerate light neutrinos case is also considered. Assuming the hierarchical Dirac neutrino masses, we find the heavy Majorana neutrino mass spectrum is either hierarchical or partial degenerate if $\\theta_{23}^{\

  12. Neutrino Masses in Superstring Derived Standard--like Models

    CERN Document Server

    Faraggi, A E; Faraggi, Alon E.; Halyo, Edi

    1993-01-01

    We propose a new scenario in a class of superstring derived standard--like models that explains the suppression of the left--handed neutrino masses. Due to nonrenormalizable terms and the breaking of the $U(1)_{Z^\\prime}$ symmetry a generalized see--saw mechanism takes place. Contrary to the traditional see--saw mechanism in GUTs, the see--saw scale and the right--handed neutrino mass scale are suppressed relative to the $U(1)_{Z^\\prime}$ breaking scale.

  13. Splitting neutrino masses and showering into Sky

    CERN Document Server

    Fargion, D; Iacovelli, M; Lanciano, O; Oliva, P; De Lucentini, P G S; Grossi, M; De Santis, M

    2006-01-01

    Neutrino masses might be as light as a few time the atmospheric neutrino mass splitting. High Energy ZeV cosmic neutrinos (in Z-Showering model) might hit relic ones at each mass in different resonance energies in our nearby Universe. This non-degenerated density and energy must split UHE Z-boson secondaries (in Z-Burst model) leading to multi injection of UHECR nucleons within future extreme AUGER energy. Secondaries of Z-Burst as neutral gamma, below a few tens EeV are better surviving local GZK cut-off and they might explain recent Hires BL-Lac UHECR correlations at small angles. A different high energy resonance must lead to Glashow's anti-neutrino showers while hitting electrons in matter. In air, Glashow's anti-neutrino showers lead to collimated and directional air-showers offering a new Neutrino Astronomy. At greater energy around PeV, Tau escaping mountains and Earth and decaying in flight are effectively showering in air sky. These Horizontal showering is splitting by geomagnetic field in forked sha...

  14. The Higgs seesaw induced neutrino masses and dark matter

    Directory of Open Access Journals (Sweden)

    Yi Cai

    2015-10-01

    Full Text Available In this paper we propose a possible explanation of the active neutrino Majorana masses with the TeV scale new physics which also provide a dark matter candidate. We extend the Standard Model (SM with a local U(1′ symmetry and introduce a seesaw relation for the vacuum expectation values (VEVs of the exotic scalar singlets, which break the U(1′ spontaneously. The larger VEV is responsible for generating the Dirac mass term of the heavy neutrinos, while the smaller for the Majorana mass term. As a result active neutrino masses are generated via the modified inverse seesaw mechanism. The lightest of the new fermion singlets, which are introduced to cancel the U(1′ anomalies, can be a stable particle with ultra flavor symmetry and thus a plausible dark matter candidate. We explore the parameter space with constraints from the dark matter relic abundance and dark matter direct detection.

  15. Comments on the determination of the neutrino mass ordering in reactor neutrino experiments

    CERN Document Server

    Bilenky, S M

    2016-01-01

    We consider the problem of determination of the neutrino mass ordering via precise study of the vacuum neutrino oscillations in the JUNO and other future medium baseline reactor neutrino experiments. We are proposing to resolve neutrino mass ordering by determination of the neutrino oscillation parameters from analysis of the data of the reactor experiments and comparison them with the oscillation parameters obtained from analysis of the solar and KamLAND experiments.

  16. Hybrid Textures of Neutrino Mass Matrix under the Lamppost of Latest Neutrino and Cosmology Data

    CERN Document Server

    Kalita, Rupam

    2015-01-01

    We study all possible neutrino mass matrices with one zero element and two equal non-zero elements, known as hybrid texture neutrino mass matrices. In the diagonal charged lepton basis, we consider thirty nine such possible cases which are consistent with the latest neutrino data. Using the two constraints on neutrino mass matrix elements imposed by hybrid textures, we numerically evaluate the neutrino parameters like the lightest neutrino mass $m_{\\text{lightest}}$, one Dirac CP phase $\\delta$ and two Majorana CP phases $\\alpha, \\beta$ by using the global fit $3\\sigma$ values of three mixing angles and two mass squared differences. We then constrain this parameter space by using the cosmological upper bound on the sum of absolute neutrino masses given by Planck experiment. We also calculate the effective neutrino mass matrix for this region of parameter space which may have relevance in future neutrinoless double beta decay experiments. We finally discriminate between these hybrid texture mass matrices from ...

  17. CMB Signals of Neutrino Mass Generation

    CERN Document Server

    Chacko, Z; Okui, T; Oliver, S J; Hall, Lawrence J.; Okui, Takemichi; Oliver, Steven J.

    2003-01-01

    We propose signals in the cosmic microwave background to probe the type and spectrum of neutrino masses. In theories that have spontaneous breaking of approximate lepton flavor symmetries at or below the weak scale, light pseudo-Goldstone bosons recouple to the cosmic neutrinos after nucleosynthesis and affect the acoustic oscillations of the electron-photon fluid during the eV era. Deviations from the Standard Model are predicted for both the total energy density in radiation during this epoch, \\Delta N_nu, and for the multipole of the n'th CMB peak at large n, \\Delta l_n. The latter signal is difficult to reproduce other than by scattering of the known neutrinos, and is therefore an ideal test of our class of theories. In many models, the large shift, \\Delta l_n \\approx 8 n_S, depends on the number of neutrino species that scatter via the pseudo-Goldstone boson interaction. This interaction is proportional to the neutrino masses, so that the signal reflects the neutrino spectrum. The prediction for \\Delta N...

  18. Neutrino Masses, Leptogenesis and Decaying Dark Matter

    CERN Document Server

    Chen, Chuan-Hung; Zhuridov, Dmitry V

    2009-01-01

    We study a simple extension of the standard model to simultaneously explain neutrino masses, dark matter and the matter-antimatter asymmetry of the Universe. In our model, the baryon asymmetry is achieved by the leptogenesis mechanism, while the decaying dark matter with the lifetime of O(10^26 s) provides a natural solution to the electron and positron excesses in Fermi and PAMELA satellite experiments. In particular, we emphasize that our model is sensitive to the structure at the endpoint around 1 TeV of the Fermi data. In addition, some of new particles proposed in the model are within the reach at the near future colliders, such as the Large Hadron Collider.

  19. Neutrino masses, leptogenesis and decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chuan-Hung [Department of Physics, National Cheng-Kung University, Tainan 701, Taiwan (China); Geng, Chao-Qiang; Zhuridov, Dmitry V., E-mail: physchen@mail.ncku.edu.tw, E-mail: geng@phys.nthu.edu.tw, E-mail: zhuridov@phys.nthu.edu.tw [Department of Physics, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

    2009-10-01

    We study a simple extension of the standard model to simultaneously explain neutrino masses, dark matter and the matter-antimatter asymmetry of the Universe. In our model, the baryon asymmetry is achieved by the leptogenesis mechanism, while the decaying dark matter with the lifetime of O(10{sup 26} s) provides a natural solution to the electron and positron excesses in Fermi and PAMELA satellite experiments. In particular, we emphasize that our model is sensitive to the structure at the endpoint around 1 TeV of the Fermi data. In addition, some of new particles proposed in the model are within the reach at the near future colliders, such as the Large Hadron Collider.

  20. Leptoquarks: Neutrino masses and accelerator phenomenology

    CERN Document Server

    Sierra, D Aristizabal; Kovalenko, S G

    2007-01-01

    Leptoquark-Higgs interactions induce mixing between leptoquark states with different chiralities once the electro-weak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1-loop order. Here we calculate the neutrino mass matrix and explore the constraints on the parameter space enforced by the assumption that LQ-loops explain current neutrino oscillation data. LQs will be produced at the LHC, if their masses are at or below the TeV scale. Since the fermionic decays of LQs are governed by the same Yukawa couplings, which are responsible for the non-trivial neutrino mass matrix, several decay branching ratios of LQ states can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. In addition, the model predicts that, if kinematically possible, heavier LQs decay into lighter ones plus either a standard model Higgs boson or a $Z^0/W^{\\pm}$ gauge boson. Thus, experiments at the LHC might be...

  1. Texture of a Four-Neutrino Mass Matrix

    CERN Document Server

    Mohanty, S; Sarkar, U; Mohanty, Subhendra; Sarkar, Utpal

    1998-01-01

    We propose a simple texture of the neutrino mass matrix with one sterile neutrino along with the three standard ones. It gives maximal mixing angles for with only four parameters, this mass matrix can explain the solar neutrino anomaly, atmospheric neutrino anomaly, LSND result and the hot dark matter of the universe, while satisfying all other Laboratory constraints. Depending on the choice of parameters, one can get the vacuum oscillation or the large angle MSW solution of the solar neutrino anomaly.

  2. Two-loop Dirac neutrino mass and WIMP dark matter

    CERN Document Server

    Bonilla, Cesar; Peinado, Eduardo; Valle, Jose W F

    2016-01-01

    We propose a "scotogenic" mechanism relating small neutrino mass and cosmological dark matter. Neutrinos are Dirac fermions with masses arising only in two--loop order through the sector responsible for dark matter. Two triality symmetries ensure both dark matter stability and strict lepton number conservation at higher orders. A global spontaneously broken U(1) symmetry leads to a physical $Diracon$ that induces invisible Higgs decays which add up to the Higgs to dark matter mode. This enhances sensitivities to spin-independent WIMP dark matter search below $m_h/2$.

  3. Supersymmetric unification in the light of neutrino mass

    Indian Academy of Sciences (India)

    Charanjit S Aulakh

    2000-04-01

    We argue that with the discovery of neutrino mass effects at super-Kamiokande there is a clear logical chain leading from the standard model through the MSSM and the recently developed minimal left right supersymmetric models with a renormalizable see-saw mechanism for neutrino mass to left right symmetric SUSY GUTS: in particular, SO(10) and SU(2) × SU(2) × SU(4). The progress in constructing such GUTS explicitly is reviewed and their testability/falsifiability by proton decay measurements emphasized

  4. Introduction to direct neutrino mass measurements and KATRIN

    CERN Document Server

    Thümmler, Thomas

    2010-01-01

    The properties of neutrinos and especially their rest mass play an important role at the intersections of cosmology, particle physics and astroparticle physics. At present there are two complementary approaches to address this topic in laboratory experiments. The search for neutrinoless double beta decay probes whether neutrinos are Majorana particles and determines an effective neutrino mass value. On the other hand experiments such as MARE, KATRIN and the recently proposed Project 8 will investigate the spectral shape of beta-decay electrons close to their kinematic endpoint in order to determine the neutrino rest mass with a model-independent method. Here, because of neutrino flavour mixing, the neutrino mass appears as an average of all neutrino mass eigenstates contributing to the electron neutrino. The KArlsruhe TRItium Neutrino experiment (KATRIN) is currently the experiment in the most advanced status of commissioning. It combines an ultra-luminous molecular windowless gaseous tritium source with an i...

  5. Higgs mass from neutrino-messenger mixing

    CERN Document Server

    Byakti, Pritibhajan; Mummidi, V Suryanarayana; Vempati, Sudhir K

    2016-01-01

    The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, $A_t$, relaxing these constraints. The detailed survey of these models \\cite{Byakti:2013ti,Evans:2013kxa} so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 15 of them can lead to Higgs mass within the observed value without raising the sfermion masses s...

  6. Type I seesaw mechanism for quasi degenerate neutrinos

    CERN Document Server

    Joshipura, Anjan S; Vempati, Sudhir K

    2009-01-01

    We discuss symmetries and scenarios leading to quasi-degenerate neutrinos in type-I seesaw models. The existence of degeneracy in the present approach is not linked to any specific structure for the Dirac neutrino Yukawa coupling matrix $y_D$ and holds in general. Basic input is the application of the minimal flavour violation principle to the leptonic sector. Generalizing this principle, we assume that the structure of the right handed neutrino mass matrix is determined by $y_D$ and the charged lepton Yukawa coupling matrix $y_l$ in an effective theory invariant under specific groups ${\\cal G}_F$ contained in the full symmetry group of the kinetic energy terms. ${\\cal G}_F$ invariance also leads to specific structure for the departure from degeneracy. The neutrino mass matrix (with degenerate mass $m_0$) resulting after seesaw mechanism has a simple form ${\\cal M}_\

  7. Neutrino mass as the probe of intermediate mass scales

    Energy Technology Data Exchange (ETDEWEB)

    Senjanovic, G.

    1980-01-01

    A discussion of the calculability of neutrino mass is presented. The possibility of neutrinos being either Dirac or Majorana particles is analyzed in detail. Arguments are offered in favor of the Majorana case: the smallness of neutrino mass is linked to the maximality of parity violation in weak interactions. It is shown how the measured value of neutrino mass would probe the existence of an intermediate mass scale, presumably in the TeV region, at which parity is supposed to become a good symmetry. Experimental consequences of the proposed scheme are discussed, in particular the neutrino-less double ..beta.. decay, where observation would provide a crucial test of the model, and rare muon decays such as ..mu.. ..-->.. e..gamma.. and ..mu.. ..-->.. ee anti e. Finally, the embedding of this model in an O(10) grand unified theory is analyzed, with the emphasis on the implications for intermediate mass scales that it offers. It is concluded that the proposed scheme provides a distinct and testable alternative for understanding the smallness of neutrino mass. 4 figures.

  8. Neutrino mass and physics beyond the Standard Model; Masse des Neutrinos et Physique au-dela du Modele Standard

    Energy Technology Data Exchange (ETDEWEB)

    Hosteins, P

    2007-09-15

    The purpose of this thesis is to study, in the neutrino sector, the flavour structures at high energy. The work is divided into two main parts. The first part is dedicated to the well known mechanism to produce small neutrino masses: the seesaw mechanism, which implies the existence of massive particles whose decays violate lepton number. Therefore this mechanism can also be used to generate a net baryon number in the early universe and explain the cosmological observation of the asymmetry between matter and antimatter. However, it is often non-trivial to fulfill the constraints coming at the same time from neutrino oscillations and cosmological experiments, at least in frameworks where the couplings can be somehow constrained, like some Grand Unification models. Therefore we devoted the first part to the study of a certain class of seesaw mechanism which can be found in the context of SO(10) theories for example. We introduce a method to extract the mass matrix of the heavy right-handed neutrinos and explore the phenomenological consequences of this quantity, mainly concerning the production of a sufficient baryon asymmetry. When trying to identify the underlying symmetry governing the mixings between the different generations, we see that there is a puzzling difference between the quark and the lepton sectors. However, the quark and lepton parameters have to be compared at the scale of the flavour symmetry breaking, therefore we have to make them run to the appropriate scale. Thus, it is worthwhile investigating models where quantum corrections allow an approximate unification of quark and lepton mixings. This is why the other part of the thesis investigates the running of the effective neutrino mass operator in models with an extra compact dimension, where quantum corrections to the neutrino masses and mixings can be potentially large due to the multiplicity of states.

  9. Neutrino masses and particle physics beyond the standard model

    CERN Document Server

    Päs, H

    2002-01-01

    The evidence for non-vanishing neutrino masses from solar and atmospheric neutrinos provides the first solid hint towards physics beyond the standard model. A full reconstruction of the neutrino spectrum may well provide a key to the theoretical structures underlying the standard model such as supersymmetry, grand unification or extra space dimensions. In this article we discuss the impact of absolute neutrinos masses on physics beyond the standard model. We review the information obtained from neutrino oscillation data and discuss the prospects of the crucial determination of the absolute neutrino mass scale, as well as the intriguing connection with the Z-burst model for extreme-energy cosmic rays.

  10. CP violations in predictive neutrino mass structures

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Chao-Qiang [Chongqing University of Posts and Telecommunications, Chongqing (China); National Tsing Hua University, Department of Physics, Hsinchu (China); National Center for Theoretical Sciences, Physics Division, Hsinchu (China); Huang, Da; Tsai, Lu-Hsing [National Tsing Hua University, Department of Physics, Hsinchu (China)

    2015-11-15

    We study the CP-violation effects from two types of neutrino mass matrices with (i) (M{sub ν}){sub ee} = 0, and (ii) (M{sub ν}){sub ee} = (M{sub ν}){sub eμ} = 0, which can be realized by the high-dimensional lepton number violating operators anti l{sub R}{sup c}γ{sup μ}L{sub L}(D{sub μ}Φ)Φ{sup 2} and @ anti l{sub R}{sup c}l{sub R}(D{sub μ}Φ){sup 2}Φ{sup 2}, respectively. In (i), the neutrino mass spectrum is in the normal ordering with the lightest neutrino mass within the range 0.002 eV neutrino-antineutrino oscillations for both mass textures of (i) and (ii), which are closely related to the CP-violating Majorana phases. (orig.)

  11. The see-saw mechanism: Neutrino mixing, leptogenesis and lepton flavour violation

    Indian Academy of Sciences (India)

    Werner Rodejohann

    2009-01-01

    The see-saw mechanism to generate small neutrino masses is reviewed. After summarizing our current knowledge about the low energy neutrino mass matrix, we consider reconstructing the see-saw mechanism. Indirect tests of see-saw are leptogenesis and lepton flavour violation in supersymmetric scenarios, which together with neutrino mass and mixing define the framework of see-saw phenomenology. Several examples are given, both phenomenological and GUT-related.

  12. Neutrino masses from SUSY: Different contributions and their implications

    Indian Academy of Sciences (India)

    Sudhir K Vempati

    2000-01-01

    We discuss the various sources of neutrino masses in supersymmetric standard models with explicit lepton number violation. We show that the bilinear lepton number violating soft terms in models with either bilinear or trilinear lepton number violating couplings in the superpotential, play an important role in determining the neutrino mass spectrum. A comparative study of the neutrino mass spectrum and its implications for the present neutrino anomalies in these models is presented.

  13. Probing Neutrino Mass Hierarchy by Comparing the Charged-Current and Neutral-Current Interaction Rates of Supernova Neutrinos

    CERN Document Server

    Lai, Kwang-Chang; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

    2016-01-01

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, $\

  14. Two-loop-induced neutrino masses: A model-independent perspective

    CERN Document Server

    Sierra, D Aristizabal

    2015-01-01

    We discuss Majorana neutrino mass generation mechanisms at the two-loop order. After briefly reviewing the systematic classification of one-loop realizations, we then focus on a general two-loop classification scheme which provides a model-independent catalog for neutrino mass models at the two-loop order

  15. Constraining the lightest neutrino mass and mee from general lepton mass matrices

    Indian Academy of Sciences (India)

    Samandeep Sharma; Gulsheen Ahuja; Manmohan Gupta

    2016-02-01

    Despite spectacular advances in fixing the neutrino mass and mixing parameters through various neutrino oscillation experiments, we still have little knowledge about the magnitudes of some vital parameters in the neutrino sector such as the absolute neutrino mass scale, effective Majorana mass mee measured in neutrinoless double beta decay. In this context, the present work aims to make an attempt to obtain some bounds for mee and the lightest neutrino mass using fairly general lepton mass matrices in the Standard Model.

  16. Neutrino-Lepton Masses, Zee Scalars and Muon g-2

    CERN Document Server

    Dicus, D A; Ng, J N; Dicus, Duane A.; He, Hong-Jian; Ng, John N.

    2001-01-01

    Evidence for neutrino oscillations is pointing to the existence of tiny but finite neutrino masses. Such masses may be naturally generated via radiative corrections in models such as the Zee model where a singlet Zee-scalar plays a key role. We minimally extend the Zee model by including a right-handed singlet neutrino \

  17. Generalized mass ordering degeneracy in neutrino oscillation experiments

    CERN Document Server

    Coloma, Pilar

    2016-01-01

    We consider the impact of neutral-current (NC) non-standard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle $\\theta_{12}$ at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence, solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-one corrections from NSI to the NC electron neutrino--quark interaction and can be tested in electron neutrino NC scattering experiments.

  18. Generalized mass ordering degeneracy in neutrino oscillation experiments

    Science.gov (United States)

    Coloma, Pilar; Schwetz, Thomas

    2016-09-01

    We consider the impact of neutral-current (NC) nonstandard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in the presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle θ12 at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-1 corrections from NSI to the NC electron neutrino-quark interaction and can be tested in electron neutrino NC scattering experiments.

  19. Improving constraints on the neutrino mass using sufficient statistics

    CERN Document Server

    Wolk, M; Bel, J; Carbone, C; Carron, J

    2015-01-01

    We use the "Dark Energy and Massive Neutrino Universe" (DEMNUni) simulations to compare the constraining power of "sufficient statistics" with the standard matter power spectrum on the sum of neutrino masses, $M_\

  20. Neutrino mass textures from F-theory

    CERN Document Server

    Antoniadis, I

    2013-01-01

    Experimental data on the neutrino mixing and masses strongly suggest an underlying approximate symmetry of the relevant Yukawa superpotential terms. Intensive phenomenological explorations during the last decade indicate that permutation symmetries such as S_4, A_4 and their subgroups, under certain assumptions and vacuum alignments, predict neutrino mass textures compatible with such data. Motivated by these findings, in the present work we analyse the neutrino properties in F-theory GUT models derived in the framework of the maximal underlying E_8 symmetry in the elliptic fibration. More specifically, we consider local F-SU(5) GUT models and study in detail spectral cover geometries with monodromies associated to the finite symmetries S_4, A_4 and their transitive subgroups, including the dihedral group D_4 and Z_2 X Z_2. We discuss various issues that emerge in the implementation of S_4, A_4 neutrino models in the F-theory context and suggest how these can be resolved. Realistic models are presented for th...

  1. Wave-packet treatment of neutrino oscillations and its implications on determining the neutrino mass hierarchy

    CERN Document Server

    Chan, Yat-Long; Tsui, Ka Ming; Wong, Chan Fai; Xu, Jianyi

    2015-01-01

    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 $\\sigma$ confidence level.

  2. Observational constraints on varying neutrino-mass cosmology

    CERN Document Server

    Geng, Chao-Qiang; Myrzakulov, R; Sami, M; Saridakis, Emmanuel N

    2016-01-01

    We consider generic models of quintessence and we investigate the influence of massive neutrino matter with field-dependent masses on the matter power spectrum. In case of minimally coupled neutrino matter, we examine the effect in tracker models with inverse power-law and double exponential potentials. We present detailed investigations for the scaling field with a steep exponential potential, non-minimally coupled to massive neutrino matter, and we derive constraints on field-dependent neutrino masses from the observational data.

  3. CP violations in predictive neutrino mass structures

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Chao-Qiang, E-mail: geng@phys.nthu.edu.tw [Chongqing University of Posts and Telecommunications, 400065, Chongqing (China); Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan (China); Huang, Da, E-mail: dahuang@phys.nthu.edu.tw; Tsai, Lu-Hsing, E-mail: lhtsai@phys.nthu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China)

    2015-11-26

    We study the CP-violation effects from two types of neutrino mass matrices with (i) (M{sub ν}){sub ee}=0, and (ii) (M{sub ν}){sub ee}=(M{sub ν}){sub eμ}=0, which can be realized by the high-dimensional lepton number violating operators ℓ{sup -bar}{sub R}{sup c}γ{sup μ}L{sub L}(D{sub μ}Φ)Φ{sup 2} and ℓ{sup -bar}{sub R}{sup c}l{sub R}(D{sub μ}Φ){sup 2}Φ{sup 2}, respectively. In (i), the neutrino mass spectrum is in the normal ordering with the lightest neutrino mass within the range 0.002 eV≲m{sub 0}≲0.007 eV. Furthermore, for a given value of m{sub 0}, there are two solutions for the two Majorana phases α{sub 21} and α{sub 31}, whereas the Dirac phase δ is arbitrary. For (ii), the parameters of m{sub 0}, δ, α{sub 21}, and α{sub 31} can be completely determined. We calculate the CP-violating asymmetries in neutrino–antineutrino oscillations for both mass textures of (i) and (ii), which are closely related to the CP-violating Majorana phases.

  4. Neutrino mass, mixing and discrete symmetries

    Science.gov (United States)

    Smirnov, Alexei Y.

    2013-07-01

    Status of the discrete symmetry approach to explanation of the lepton masses and mixing is summarized in view of recent experimental results, in particular, establishing relatively large 1-3 mixing. The lepton mixing can originate from breaking of discrete flavor symmetry Gf to different residual symmetries Gl and Gv in the charged lepton and neutrino sectors. In this framework the symmetry group condition has been derived which allows to get relations between the lepton mixing elements immediately without explicit model building. The condition has been applied to different residual neutrino symmetries Gv. For generic (mass independent) Gv = Z2 the condition leads to two relations between the mixing parameters and fixes one column of the mixing matrix. In the case of Gv = Z2 × Z2 the condition fixes the mixing matrix completely. The non-generic (mass spectrum dependent) Gv lead to relations which include mixing angles, neutrino masses and Majorana phases. The symmetries Gl, Gv, Gf are identified which lead to the experimentally observed values of the mixing angles and allow to predict the CP phase.

  5. Neutrino Masses and Scalar Singlet Dark Matter

    CERN Document Server

    Bhattacharya, Subhaditya; Nandi, S

    2016-01-01

    We propose a simple extension of the Standard Model (SM) which has a viable dark matter (DM) candidate, as well as can explain the generation of tiny neutrino masses. The DM is an electroweak (EW) singlet scalar $S$, odd under an imposed exact $Z_2$ symmetry, interacting to SM through `Higgs-portal' coupling, while all other particles are even under $Z_2$. The model also has an EW isospin $3/2$ scalar, $\\Delta$ and a pair of EW isospin vector, $\\Sigma$ and $\\bar{\\Sigma}$, responsible for generating tiny neutrino mass via the effective dimension seven operator. Thanks to the additional interactions with $\\Delta$, the scalar singlet DM $S$ survives a large region of parameter space by relic density constraints from WMAP/PLANCK and direct search bounds from updated LUX data. Constraints on the model from Large Hadron Collider (LHC) has also been discussed.

  6. Neutrino masses and scalar singlet dark matter

    Science.gov (United States)

    Bhattacharya, Subhaditya; Jana, Sudip; Nandi, S.

    2017-03-01

    We propose a simple extension of the Standard Model (SM) which has a viable dark matter (DM) candidate and can explain the generation of tiny neutrino masses. The DM is an electroweak (EW) singlet scalar S , odd under an imposed exact Z2 symmetry, that interacts with the SM through the "Higgs portal" coupling, while all other particles are even under Z2. The model also has an EW isospin 3 /2 scalar Δ and a pair of EW isospin vectors Σ and Σ ¯, which are responsible for generating tiny neutrino mass via the effective dimension-seven operator. Thanks to the additional interactions with Δ , the scalar singlet DM S survives a large region of parameter space by relic density constraints from WMAP/Planck and direct search bounds from updated LUX data. Constraints on the model from the LHC are also discussed.

  7. Models of neutrino mass, mixing and CP violation

    Science.gov (United States)

    King, Stephen F.

    2015-12-01

    In this topical review we argue that neutrino mass and mixing data motivates extending the Standard Model (SM) to include a non-Abelian discrete flavour symmetry in order to accurately predict the large leptonic mixing angles and {C}{P} violation. We begin with an overview of the SM puzzles, followed by a description of some classic lepton mixing patterns. Lepton mixing may be regarded as a deviation from tri-bimaximal mixing, with charged lepton corrections leading to solar mixing sum rules, or tri-maximal lepton mixing leading to atmospheric mixing rules. We survey neutrino mass models, using a roadmap based on the open questions in neutrino physics. We then focus on the seesaw mechanism with right-handed neutrinos, where sequential dominance (SD) can account for large lepton mixing angles and {C}{P} violation, with precise predictions emerging from constrained SD (CSD). We define the flavour problem and discuss progress towards a theory of favour using GUTs and discrete family symmetry. We classify models as direct, semidirect or indirect, according to the relation between the Klein symmetry of the mass matrices and the discrete family symmetry, in all cases focussing on spontaneous {C}{P} violation. Finally we give two examples of realistic and highly predictive indirect models with CSD, namely an A to Z of flavour with Pati-Salam and a fairly complete A 4 × SU(5) SUSY GUT of flavour, where both models have interesting implications for leptogenesis.

  8. On the Predictivity of Neutrino Mass Sum Rules

    CERN Document Server

    Gehrlein, Julia; Spinrath, Martin

    2016-01-01

    Correlations between light neutrino observables are arguably the strongest predictions of lepton flavour models based on (discrete) symmetries, except for the very few cases which unambiguously predict the full set of leptonic mixing angles. A subclass of these correlations are neutrino mass sum rules, which connect the three (complex) light neutrino mass eigenvalues among each other. This connection constrains both the light neutrino mass scale and the Majorana phases, so that mass sum rules generically lead to a non-zero value of the lightest neutrino mass and to distinct predictions for the effective mass probed in neutrinoless double beta decay. However, in nearly all cases known, the neutrino mass sum rules are not exact and receive corrections from various sources. We introduce a formalism to handle these corrections perturbatively in a model-independent manner, which overcomes issues present in earlier approaches. Our ansatz allows us to quantify the modification of the predictions derived from neutrin...

  9. Time-of-flight delay between oscillating neutrinos and gravitational waves from supernovae and the neutrino mass problem

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias]. E-mail: hermanjc@cbpf.br

    2001-04-01

    Neutrino oscillations during core bounce of a supernova collapse may induce detectable gravitational-wave bursts by the time they are trapped in the core. For large-scale distances the flavor changing neutrinos get delayed on its trip to earth while the gravitational waves they emit do not. Since the oscillation mechanism sets up the offset for both emissions, this fact yields in a time-of-flight delay between both the radiations that, whenever measured, could provide an inedit estimative of the absolute scale of neutrino masses. (author)

  10. Time-of-flight delay between oscillating neutrinos and gravitational waves from supernovae and the neutrino mass problem

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias]. E-mail: hermanjc@cbpf.br

    2001-04-01

    Neutrino oscillations during core bounce of a supernova collapse may induce detectable gravitational-wave bursts by the time they are trapped in the core. For large-scale distances the flavor changing neutrinos get delayed on its trip to earth while the gravitational waves they emit do not. Since the oscillation mechanism sets up the offset for both emissions, this fact yields in a time-of-flight delay between both the radiations that, whenever measured, could provide an inedit estimative of the absolute scale of neutrino masses. (author)

  11. The GSI method for studying neutrino mass differences - For Pedestrians

    OpenAIRE

    Lipkin, Harry J.

    2008-01-01

    A new experiment studying the behavior of a radioactive ion before its weak decay by K-capture suggests that neutrino masses and mixing can be investigated without detecting the neutrino. Every weak decay can be observed, thus avoiding the suppression by the low neutrino absorption cross section of the signal in conventional neutrino oscillation experiments. The normally unobservable long wave lengths are made observable by having the radioactive source move a long distance circulating around...

  12. Neutrino Masses and Mixing one Decade from Now

    CERN Document Server

    González-Garciá, M Concepción

    2000-01-01

    We review the status of neutrino masses and mixings in the light of the solar and atmospheric neutrino data. The result from the LSND experiment is also considered. We discuss the present knowledge and the expected sensitivity to the neutrino mixing parameters in the simplest schemes proposed to reconcile these data some of which include a light sterile neutrino in addition to the three standard ones.

  13. Type I seesaw mechanism for quasi-degenerate neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Joshipura, Anjan S., E-mail: anjan@prl.res.i [Physical Research Laboratory, Navarangpura, Ahmedabad 380 009 (India); Patel, Ketan M., E-mail: kmpatel@prl.res.i [Physical Research Laboratory, Navarangpura, Ahmedabad 380 009 (India); Vempati, Sudhir K., E-mail: vempati@cts.iisc.ernet.i [Centre for High Energy Physics, Indian Inst. of Science, Bangalore 560 012 (India)

    2010-06-21

    We discuss symmetries and scenarios leading to quasi-degenerate neutrinos in type I seesaw models. The existence of degeneracy in the present approach is not linked to any specific structure for the Dirac neutrino Yukawa coupling matrix y{sub D} and holds in general. Basic input is the application of the minimal flavour violation principle to the leptonic sector. Generalizing this principle, we assume that the structure of the right-handed neutrino mass matrix is determined by y{sub D} and the charged lepton Yukawa coupling matrix y{sub l} in an effective theory invariant under specific groups G{sub F} contained in the full symmetry group of the kinetic energy terms. G{sub F} invariance also leads to specific structure for the departure from degeneracy. The neutrino mass matrix (with degenerate mass m{sub 0}) resulting after seesaw mechanism has a simple form M{sub {nu}{approx}m0}(I-py{sub l}y{sub l}{sup T}) in one particular scenario based on supersymmetry. This form is shown to lead to correct description of neutrino masses and mixing angles. The thermal leptogenesis after inclusion of flavour effects can account for the observed baryon asymmetry of the universe within the present scenario. Rates for lepton flavour violating processes can occur at observable levels in the supersymmetric version of the scenario.

  14. Neutrino Mass Models in Extra Dimensions

    CERN Document Server

    Ng, J N

    2003-01-01

    Neutrinos play a crucial role in many areas of physics from very short distances to astrophysics and cosmology. It is a long held believe that they are good probes of physics at the GUT scale. Recent developments have made it clear that they can also be of fundamental importance for the physics of extra dimensions if these exist. Here we pedagogically review the construction of neutrino mass models in extra dimensions within the brane world scenarios. These models are usually nontrivial generalizations of their four dimensional counterparts. We describe the theoretical tools that have been forged and the new perpectives gained in this rapidly developing area. In particular we discuss the issues involve in building models without the use of right-handed singlets. It is very difficult to directly test the origin of neutrino masses in different models be it in four or more dimensions. We point out that different models give very different indirect signatures in the TeV region and in precision measurements.

  15. Neutrino masses and spontaneously broken flavor symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Staudt, Christian

    2014-06-16

    We study the phenomenology of supersymmetric flavor models. We show how the predictions of models based on spontaneously broken non-Abelian discrete flavor symmetries are altered when we include so-called Kaehler corrections. Furthermore, we discuss anomaly-free discrete R symmetries which are compatible with SU(5) unification. We find a set of symmetries compatible with suppressed Dirac neutrino masses and a unique symmetry consistent with the Weinberg operator. We also study a pseudo-anomalous U(1){sub R} symmetry which explains the fermion mass hierarchies and, when amended with additional singlet fields, ameliorates the fine-tuning problem.

  16. Implications of results of neutrino mass experiments

    Energy Technology Data Exchange (ETDEWEB)

    McKellar, B.H.; Garbutt, M. [and others

    2000-10-01

    The long standing negative (mass){sup 2} anomaly encountered in attempts to measure the mass of the electron neutrino may be an indication of physics beyond the standard model. It is demonstrated that an additional charged current interaction which is not of V--A form, and which is at least an order of magnitude weaker than the standard model charged current interaction, will produce a spectrum, which, if fitted by the standard model, may give a negative value for m{sub {nu}}{sup 2}. A possible physical explanation of the time dependent effects seen by the Troitsk experiment is also provided.

  17. Common origin of neutrino mass, dark matter and Dirac leptogenesis

    Science.gov (United States)

    Borah, Debasish; Dasgupta, Arnab

    2016-12-01

    We study the possibility of generating tiny Dirac neutrino masses at one loop level through the scotogenic mechanism such that one of the particles going inside the loop can be a stable cold dark matter (DM) candidate. Majorana mass terms of singlet fermions as well as tree level Dirac neutrino masses are prevented by incorporating the presence of additional discrete symmetries in a minimal fashion, which also guarantee the stability of the dark matter candidate. Due to the absence of total lepton number violation, the observed baryon asymmetry of the Universe is generated through the mechanism of Dirac leptogenesis where an equal and opposite amount of leptonic asymmetry is generated in the left and right handed sectors which are prevented from equilibration due to tiny Dirac Yukawa couplings. Dark matter relic abundance is generated through its usual freeze-out at a temperature much below the scale of leptogenesis. We constrain the relevant parameter space from neutrino mass, baryon asymmetry, Planck bound on dark matter relic abundance, and latest LUX bound on spin independent DM-nucleon scattering cross section. We also discuss the charged lepton flavour violation (μ → e γ) and electric dipole moment of electron in this model in the light of the latest experimental data and constrain the parameter space of the model.

  18. Models of Neutrino Mass, Mixing and CP Violation

    CERN Document Server

    King, Stephen F

    2015-01-01

    In this topical review we argue that neutrino mass and mixing data motivates extending the Standard Model to include a non-Abelian discrete flavour symmetry in order to accurately predict the large leptonic mixing angles and CP violation. We begin with an overview of the Standard Model puzzles, followed by a description of some classic lepton mixing patterns. Lepton mixing may be regarded as a deviation from tri-bimaximal mixing, with charged lepton corrections leading to solar mixing sum rules, or tri-maximal lepton mixing leading to atmospheric mixing rules. We survey neutrino mass models, using a roadmap based on the open questions in neutrino physics. We then focus on the seesaw mechanism with right-handed neutrinos, where sequential dominance (SD) can account for large lepton mixing angles and CP violation, with precise predictions emerging from constrained SD (CSD). We define the flavour problem and discuss progress towards a theory of flavour using GUTs and discrete family symmetry. We classify models ...

  19. Double seesaw mechanism in a left-right symmetric model with TeV neutrinos

    CERN Document Server

    Almeida, F M L de; Simões, J A Martins; Ramalho, A J; Pinto, L Ribeiro; Wulck, S; Vale, M A B do

    2010-01-01

    A left-right symmetric model is discussed with new mirror fermions and a Higgs sector with two doublets and neutral scalar singlets. The seesaw mechanism is generalized, including not only neutrino masses but also charged fermion masses. The spectrum of heavy neutrinos presents a second seesaw mass matrix and has neutrinos masses naturally in the TeV region. The model has very clear signatures for the new neutral vector gauge bosons. Two classes of models are discussed. New mirror neutrinos can be very light and a new $Z^{\\prime}$ can be discriminated from other models by a very high invisible branching fraction. The other possibility is that mirror neutrinos can have masses naturally in the TeV region and can be produced through $Z^{\\prime}$ decays into heavy neutrino pairs. Signatures and production processes for the model at the LHC energy are also presented.

  20. Near Maximal Atmospheric Neutrino Mixing in Neutrino Mass Models with Two Texture Zeros

    CERN Document Server

    Dev, S; Singh, Lal; Gupta, Manmohan

    2014-01-01

    The implications of a large value of the effective Majorana neutrino mass for a class of two texture zero neutrino mass matrices have been studied in the flavor basis. It is found that these textures predict near maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. It is noted that this prediction is independent of the values of solar and reactor neutrino mixing angles. We present the symmetry realization of these textures using the discrete cyclic group $Z_3$. It is found that the texture zeros realised in this work remain stable under renormalization group running of the neutrino mass matrix from the seesaw scale to the electroweak scale, at one loop level.

  1. Radiative generation of neutrino mixing: degenerate masses and threshold corrections

    CERN Document Server

    Hollik, Wolfgang Gregor

    2014-01-01

    Degenerate neutrino masses are excluded by experiment. The experimentally measured mass squared differences together with the yet undetermined absolute neutrino mass scale allow for a quasi-degenerate mass spectrum. For the lightest neutrino mass larger than roughly 0.1 eV, we analyse the influence of threshold corrections at the electroweak scale. We show that typical one-loop corrections can generate the observed neutrino mixing as well as the mass differences starting from exactly degenerate masses at the tree-level. Those threshold corrections have to be explicitly flavour violating. Flavour diagonal, non-universal corrections are not sufficient to simultaneously generate the correct mixing and the mass differences. We apply the new insights to an extension of the Minimal Supersymmetric Standard Model with non-minimal flavour violation in the soft breaking terms and discuss the low-energy threshold corrections to the light neutrino mass matrix in that model.

  2. Neutrino Oscillations, SUSY See-Saw Mechanism and Charged Lepton Flavor Violation

    CERN Document Server

    Deppisch, F; Redelbach, A; Rückl, R; Shimizu, Y

    2003-01-01

    Neutrino oscillations give clear evidence for non-vanishing neutrino masses and lepton-flavor violation (LFV) in the neutrino sector. This provides strong motivation to search for signals of LFV also in the charged lepton sector, and to probe the SUSY see-saw mechanism. We compare the sensitivity of rare radiative decays on the right-handed Majorana mass scale M_R with the reach in slepton-pair production at a future linear collider.

  3. A new neutrino mass sum rule from inverse seesaw

    CERN Document Server

    Dorame, L; Peinado, E; Rojas, Alma D; Valle, J W F

    2012-01-01

    A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). One of these implies in a lower bound on the effective neutrinoless double beta mass parameter, even for normal hierarchy neutrinos. Here we propose a new model based on the S4 flavor symmetry that leads to the new neutrino mass sum-rule and discuss how to generate a nonzero value for the reactor mixing angle indicated by recent experiments, and the resulting correlation with the solar mixing angle.

  4. Flavor Ratios and Mass Hierarchy at Neutrino Telescopes

    CERN Document Server

    Fu, Lingjun

    2014-01-01

    The observation of high-energy extraterrestrial neutrinos at IceCube represents the beginning of the era of neutrino astronomy. In this paper, we study the cosmic neutrino flavor ratios against the Dirac CP-violating phase at neutrino telescopes, taking into account of the charged-current and neutral-current interactions at the detectors. We then demonstrate how to probe mass hierarchy at neutrino telescopes by the precise measurements of the cosmic neutrino flavor ratios. We show that the sensitivity of our scheme is independent of the undetermined values of the Dirac CP-violating phase. We also explore the possible effects of active-sterile mixing, neutrino decay and pseudo-Dirac nature of neutrinos.

  5. Introduction to direct neutrino mass measurements and KATRIN

    Science.gov (United States)

    Thümmler, T.; Katrin Collaboration

    2012-08-01

    The properties of neutrinos and especially their rest mass play an important role at the intersections of cosmology, particle physics and astroparticle physics. At present there are two complementary approaches to address this topic in laboratory experiments. The search for neutrinoless double beta decay probes whether neutrinos are Majorana particles and determines an effective neutrino mass value. On the other hand experiments such as MARE, KATRIN and the recently proposed Project 8 will investigate the spectral shape of β-decay electrons close to their kinematic endpoint in order to determine the neutrino rest mass with a model-independent method. Here, because of neutrino flavour mixing, the neutrino mass appears as an average of all neutrino mass eigenstates contributing to the electron neutrino. The KArlsruhe TRItium Neutrino experiment (KATRIN) is currently the experiment in the most advanced status of commissioning. It combines an ultra-luminous molecular windowless gaseous tritium source with an integrating high-resolution spectrometer of MAC-E filter type. It will investigate the neutrino rest mass with 0.2 eV/c (90% C.L.) sensitivity and allow β spectroscopy close to the T endpoint at 18.6 keV with unprecedented precision.

  6. Neutrino Physics

    CERN Document Server

    Langacker, P; Peinado, E; Langacker, Paul; Erler, Jens; Peinado, Eduardo

    2005-01-01

    The theoretical and experimental bases of neutrino mass and mixing are reviewed. A brief chronological evolution of the weak interactions, the electroweak Standard Model, and neutrinos is presented. Dirac and Majorana mass terms are explained as well as models such as the seesaw mechanism. Schemes for two, three and four neutrino mixings are presented.

  7. Probing the neutrino mass matrix in next generation neutrino oscillation experiments

    OpenAIRE

    2005-01-01

    We review the current status of the neutrino mass and mixing parameters needed to reconstruct the neutrino mass matrix. A comparative study of the precision in the measurement of oscillation parameters expected from the next generation solar, atmospheric, reactor and accelerator based experiments is presented. We discuss the potential of $0\

  8. Neutrino mass hierarchy determination at reactor antineutrino experiments

    CERN Document Server

    Yang, Guang

    2015-01-01

    After the neutrino mixing angle $\\theta_{13}$ has been precisely measured by the reactor antineutrino experiments, one of the most important open questions left in neutrino physics is the neutrino mass hierarchy. Jiangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy (MH) without exploring the matter effect. The JUNO site location is optimized to have the best sensitivity for the mass hierarchy determination. JUNO will employ a 20 kton liquid scintillator detector located in a laboratory 700 meters underground. The excellent energy resolution and PMT coverage will give us an unprecedented opportunity to reach a 3-4 $\\sigma$ precision. In this paper, the JUNO detector design and simulation work will be presented. Also, RENO-50, another medium distance reactor antineutrino experiment, will do a similar measurement. With the efforts of these experiments, it is very likely that the neutrino mass hierarchy will be determined in the next 10 years.

  9. White Paper: Measuring the Neutrino Mass Hierarchy

    CERN Document Server

    Cahn, R N; Freedman, S J; Haxton, W C; Kadel, R W; Kolomensky, Yu G; Luk, K B; McDonald, P; Gann, G D Orebi; Poon, A W P

    2013-01-01

    This white paper is a condensation of a report by a committee appointed jointly by the Nuclear Science and Physics Divisions at Lawrence Berkeley National Laboratory (LBNL). The goal of this study was to identify the most promising technique(s) for resolving the neutrino mass hierarchy. For the most part, we have relied on calculations and simulations presented by the proponents of the various experiments. We have included evaluations of the opportunities and challenges for these experiments based on what is available already in the literature.

  10. Neutrino masses beyond the tree level

    CERN Document Server

    Sierra, D Aristizabal

    2011-01-01

    Models for Majorana neutrino masses can be classified according to the level in perturbation theory at which the effective dimension five operator $LLHH$ is realized. The possibilities range from the tree-level up to the three-loop level realizations. We discuss some general aspects of this approach and speculate about a model independent classification of the possible cases. Among all the realizations, those in which the effective operator is induced by radiative corrections open the possibility for lepton number violation near -or at- the electroweak scale. We discuss some phenomenological aspects of two generic radiative realizations: the Babu-Zee model and supersymmetric models with bilinear R-parity violation.

  11. Relaxing neutrino mass bounds by a running cosmological constant

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, F.; Schrempp, L.

    2007-11-15

    We establish an indirect link between relic neutrinos and the dark energy sector which originates from the vacuum energy contributions of the neutrino quantum fields. Via renormalization group effects they induce a running of the cosmological constant with time which dynamically influences the evolution of the cosmic neutrino background. We demonstrate that the resulting reduction of the relic neutrino abundance allows to largely evade current cosmological neutrino mass bounds and discuss how the scenario might be probed by the help of future large scale structure surveys and Planck data. (orig.)

  12. Model independent constraints on mass-varying neutrino scenarios

    CERN Document Server

    Franca, Urbano; Lesgourgues, Julien; Pastor, Sergio

    2009-01-01

    Models of dark energy in which neutrinos interact with the scalar field supposed to be responsible for the acceleration of the universe usually imply a variation of the neutrino masses on cosmological time scales. In this work we propose a parameterization for the neutrino mass variation that captures the essentials of those scenarios and allows to constrain them in a model independent way, that is, without resorting to any particular scalar field model. Using WMAP 5yr data combined with the matter power spectrum of SDSS and 2dFGRS, the limit on the present value of the neutrino mass is $m_0 \\equiv m_{\

  13. Electroweak absolute, meta-, and thermal stability in neutrino mass models

    Science.gov (United States)

    Lindner, Manfred; Patel, Hiren H.; Radovčić, Branimir

    2016-04-01

    We analyze the stability of the electroweak vacuum in neutrino mass models containing right-handed neutrinos or fermionic isotriplets. In addition to considering absolute stability, we place limits on the Yukawa couplings of new fermions based on metastability and thermal stability in the early Universe. Our results reveal that the upper limits on the neutrino Yukawa couplings can change significantly when the top quark mass is allowed to vary within the experimental range of uncertainty in its determination.

  14. Electroweak Absolute, Meta-, and Thermal Stability in Neutrino Mass Models

    CERN Document Server

    Lindner, Manfred; Radovčić, Branimir

    2015-01-01

    We analyze the stability of the electroweak vacuum in neutrino mass models containing right handed neutrinos or fermionic isotriplets. In addition to considering absolute stability, we place limits on the Yukawa couplings of new fermions based on metastability and thermal stability in the early Universe. Our results reveal that the upper limits on the neutrino Yukawa couplings can change significantly when the top quark mass is allowed to vary within the experimental range of uncertainty in its determination.

  15. Tiny neutrino mass from SUSY and lepton number breaking sector

    Energy Technology Data Exchange (ETDEWEB)

    Haba, Naoyuki [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Shindou, Tetsuo, E-mail: shindou@cc.kogakuin.ac.jp [Faculty of Engineering, Kogakuin University, Tokyo 163-8677 (Japan)

    2011-07-04

    We suggest a new setup where SUSY breaking spurion F-term possesses lepton number. This setup not only modifies sparticle mass spectra but also realizes several new models, where neutrino mass is naturally induced through radiative corrections. We here suggest two new models; the first one is (i): pseudo-Dirac/Schizophrenic neutrino model, and the second one is (ii): pure Majorana neutrino model. We will also show this setup can naturally apply to the supersymmetric Zee-Babu model.

  16. Matter-antimatter oscillations and neutrino mass

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Radiative Neutrino Mass with Scotogenic Scalar Triplet

    CERN Document Server

    Brdar, Vedran; Radovcic, Branimir

    2014-01-01

    We present radiative one-loop neutrino mass model with hypercharge zero scalar triplet in conjunction with another charged singlet scalar and an additional vectorlike lepton doublet. We study three variants of this mass model: the first one without additional beyond-SM symmetry, the second with imposed DM-stabilizing discrete Z_2 symmetry, and the third in which this Z_2 symmetry is promoted to the gauge symmetry U(1)_D. The two latter cases are scotogenic, with a neutral component of the scalar triplet as a dark matter candidate. In first scotogenic model the Z_2-odd dark matter candidate is at the multi-TeV mass scale, so that all new degrees of freedom are beyond the direct reach of the LHC. In second scotogenic setup, with broken U(1)_D symmetry the model may have LHC signatures or be relevant to astrophysical observations, depending on the scale of U(1)_D breaking.

  18. See-saw mechanism and four light neutrino state

    OpenAIRE

    Czakon, M.; Gluza, J.; Zralek, M.

    2001-01-01

    A formal proof is given that in a see-saw type neutrino mass matrix with only two neutrino mass scales ($m_D \\ll m_R$) and the maximal rank of $m_{R(D)}$, we can not get a fourth light sterile neutrino.

  19. See-saw mechanism and four light neutrino state

    OpenAIRE

    Czakon, M.; Gluza, J.; Zralek, M.

    2001-01-01

    A formal proof is given that in a see-saw type neutrino mass matrix with only two neutrino mass scales ($m_D \\ll m_R$) and the maximal rank of $m_{R(D)}$, we can not get a fourth light sterile neutrino.

  20. The Neutrinoless Double Beta Decay, Physics beyond the Standard Model and the Neutrino Mass

    CERN Document Server

    Faessler, Amand

    2012-01-01

    The Neutrinoless double beta Decay allows to determine the effectice Majorana electron neutrino mass. For this the following conditions have to be satisfied: (i) The neutrino must be a Majorana particle, i. e. identical to the antiparticle. (ii) The half life has to be measured. (iii)The transition matrix element must be reliably calculated. (iv) The leading mechanism must be the light Majorana neutrino exchange. The present contribution studies the accuracy with which one can calculate by different methods: (1) Quasi-Particle Random Phase Approach (QRPA), (2) the Shell Model (SM), (3) the (before the variation) angular momentum projected Hartree-Fock-Bogoliubov method (PHFB)and the (4) Interacting Boson Approach (IBA). In the second part we investigate how to determine experimentally the leading mechanism for the Neutrinoless Double Beta Decay. Is it (a) the light Majorana neutrino exchange as one assumes to determine the effective Majorana neutrino mass, ist it the heavy left (b) or right handed (c) Majoran...

  1. A Probability Density Function for Neutrino Masses and Mixings

    CERN Document Server

    Fortin, Jean-François; Marleau, Luc

    2016-01-01

    The anarchy principle leading to the see-saw ensemble is studied analytically with the usual tools of random matrix theory. The probability density function for the see-saw ensemble of $N\\times N$ matrices is obtained in terms of a multidimensional integral. This integral involves all light neutrino masses, leading to a complicated probability density function. It is shown that the probability density function for the neutrino mixing angles and phases is the appropriate Haar measure. The decoupling of the light neutrino masses and neutrino mixings implies no correlation between the neutrino mass eigenstates and the neutrino mixing matrix, in contradiction with observations but in agreement with some of the claims found in the literature.

  2. Probability density function for neutrino masses and mixings

    Science.gov (United States)

    Fortin, Jean-François; Giasson, Nicolas; Marleau, Luc

    2016-12-01

    The anarchy principle leading to the seesaw ensemble is studied analytically with the usual tools of random matrix theory. The probability density function for the seesaw ensemble of N ×N matrices is obtained in terms of a multidimensional integral. This integral involves all light neutrino masses, leading to a complicated probability density function. It is shown that the probability density function for the neutrino mixing angles and phases is the appropriate Haar measure. The decoupling of the light neutrino masses and neutrino mixings implies no correlation between the neutrino mass eigenstates and the neutrino mixing matrix and leads to a loss of predictive power when comparing with observations. This decoupling is in agreement with some of the claims found in the literature.

  3. Hybrid method to resolve the neutrino mass hierarchy by supernova (anti)neutrino induced reactions

    CERN Document Server

    Vale, D; Paar, N

    2015-01-01

    We introduce a hybrid method to determine the neutrino mass hierarchy by simultaneous measurements of responses of at least two detectors to antineutrino and neutrino fluxes from accretion and cooling phases of core-collapse supernovae. The (anti)neutrino-nucleus cross sections for $^{56}$Fe and $^{208}$Pb are calculated in the framework of the relativistic nuclear energy density functional and weak interaction Hamiltonian, while the cross sections for inelastic scattering on free protons $\\mathrm{p}(\\bar{\

  4. Measuring neutrino masses with a future galaxy survey

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Wong, Yvonne Y. Y.

    2012-01-01

    the persistent degeneracies between the neutrino mass, the physical matter density, and the Hubble parameter. Notwithstanding this remarkable sensitivity to sum m_nu, Euclid-like shear and galaxy data will not be sensitive to the exact mass spectrum of the neutrino sector; no significant bias (

  5. Unification of gauge couplings in radiative neutrino mass models

    DEFF Research Database (Denmark)

    Hagedorn, Claudia; Ohlsson, Tommy; Riad, Stella

    2016-01-01

    We investigate the possibility of gauge coupling unification in various radiative neutrino mass models, which generate neutrino masses at one- and/or two-loop level. Renormalization group running of gauge couplings is performed analytically and numerically at one- and two-loop order, respectively...

  6. Friedberg-Lee symmetry and tribimaximal neutrino mixing in the inverse seesaw mechanism

    Science.gov (United States)

    Chan, Aik Hui; Low, Hwee Boon; Xing, Zhi-Zhong

    2009-10-01

    The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact μ-τ symmetry in the gauge-singlet neutrino sector, and obtain the tribimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that nonunitary corrections to this result can possibly reach the percent level, and a soft breaking of μ-τ symmetry can give rise to CP violation in such a TeV-scale seesaw scenario.

  7. Friedberg-Lee symmetry and tri-bimaximal neutrino mixing in the inverse seesaw mechanism

    CERN Document Server

    Chan, Aik Hui; Xing, Zhi-zhong

    2009-01-01

    The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly-proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact \\mu-\\tau symmetry in the gauge-singlet neutrino sector and obtain the tri-bimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that non-unitary corrections to this result are possible to reach the percent level and a soft breaking of \\mu-\\tau symmetry can give rise to CP violation in such a TeV-scale seesaw scenario.

  8. Leptonic Unitarity Triangles and Effective Mass Triangles of the Majorana Neutrinos

    CERN Document Server

    Xing, Zhi-zhong

    2015-01-01

    Given the best-fit results of six neutrino oscillation parameters, we plot the Dirac and Majorana unitarity triangles (UTs) of the $3\\times 3$ lepton flavor mixing matrix to show their real shapes for the first time. The connections of the Majorana UTs with neutrino-antineutrino oscillations and neutrino decays are explored, and the possibilities of right or isosceles UTs are discussed. In the neutrino mass limit of $m^{}_1 \\to 0$ or $m^{}_3 \\to 0$, which is allowed by current experimental data, we show how the six triangles formed by the effective Majorana neutrino masses $\\langle m\\rangle^{}_{\\alpha\\beta}$ (for $\\alpha, \\beta = e, \\mu, \\tau$) and their corresponding component vectors look like in the complex plane. The relations of such triangles to the Majorana phases and to the lepton-number-violating decays $H^{++} \\to \\alpha^+ \\beta^+$ in the type-II seesaw mechanism are also illustrated.

  9. New supersymmetric source of neutrino masses and mixings

    CERN Document Server

    Casas, J A; Navarro, I

    2002-01-01

    Conventionally, neutrino masses in a supersymmetric theory arise from non-renormalizable lepton-number (L)-violating operators in the superpotential. The alternative possibility of having such operators in the Kahler potential as the dominant source of neutrino masses has very interesting implications and differences with respect to the standard scenario: first, the scale of L-violation can be lowered dramatically and neutrino masses have a different tan beta-dependence; second, the renormalization of these operators has remarkable properties: in many cases it improves drastically the stability of neutrino textures against radiative corrections, while in others it makes possible to generate radiatively large mixing angles in a natural way. In particular, the mass splitting and mixing angle of solar neutrinos (LAMSW solution) can be explained as a purely radiative effect.

  10. Flavor structure in D-brane models: Majorana neutrino masses

    Science.gov (United States)

    Hamada, Yuta; Kobayashi, Tatsuo; Uemura, Shohei

    2014-05-01

    We study the flavor structure in intersecting D-brane models. We study anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino masses, which can be generated by D-brane instanton effects. It is found that a certain pattern of mass matrix is obtained and the cyclic permutation symmetry remains unbroken. As a result, trimaximal mixing matrix can be realized if Dirac neutrino mass and charged lepton mass matrices are diagonal.

  11. Flavor structure in D-brane models: Majorana neutrino masses

    CERN Document Server

    Hamada, Yuta; Uemura, Shohei

    2014-01-01

    We study the flavor structure in intersecting D-brane models. We study anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino masses, which can be generated by D-brane instanton effects. It is found that a certain pattern of mass matrix is obtained and the cyclic permutation symmetry remains unbroken. As a result, trimaximal mixing matrix can be realized if Dirac neutrino mass and charged lepton mass matrices are diagonal.

  12. Majorana neutrino masses from anomalous U(1) symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Leontaris, G.K. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece)]. E-mail: leonta@artemis1.physics.uoi.gr; Rizos, J. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece); Psallidas, A. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece)

    2004-09-09

    We explore the possibility of interpreting the solar and atmospheric neutrino data within the context of the Minimal Supersymmetric Standard Model augmented by a single U(1) anomalous family symmetry spontaneously broken by non-zero vacuum expectation values of a pair of singlet fields. The symmetry retains a dimension-five operator which provides Majorana masses for left-handed neutrino states. Assuming symmetric lepton mass matrices, the model predicts inverse hierarchical neutrino mass spectrum, {theta}13=0 and large mixing while at the same time it provides acceptable mass matrices for the charged fermions.

  13. Detecting the Neutrinos Mass Hierarchy from Cosmological Data

    CERN Document Server

    Xu, Lixin

    2016-01-01

    We propose a new parameterization to measure the neutrino mass hierarchy, namely $\\Delta=(m_3-m_1)/(m_1+m_3)$ which is dimensionless and varies in the range $[-1,1]$. Taking into account the results of neutrino oscillation experiments, $\\Delta$ is the unique parameter for determining all the masses of neutrinos, and a positive (negative) sign of $\\Delta$ denotes the normal (inverted) mass hierarchy. Adopting the currently available cosmic observations, we find that the normal mass hierarchy is slightly favored, and the mass of lightest neutrino is less than $0.030$ eV for the normal mass hierarchy and $0.024$ eV for the inverted mass hierarchy at $95\\%$ confidence level.

  14. Baryogenesis, neutrino masses, and dynamical dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Eisele, M.T.

    2007-10-09

    This thesis considers several models that connect different areas of particle physics and cosmology. Our first discussion in this context concerns a baryogenesis scenario, in which the baryon asymmetry of our universe is created through the dynamics of a dark energy field, thereby illustrating that these two topics might be related. Subsequently, several neutrino mass models are analyzed, which make use of an extra-dimensional setting to overcome certain problems of their fourdimensional counterparts. The central discussion of this thesis concerns a leptogenesis model with many standard model singlets. Amongst other things, we show that the presence of these states can lower the standard bound for the necessary reheating temperature of the universe by at least one and a half orders of magnitude. To further motivate this approach, we also discuss an explicit, extradimensional leptogenesis scenario that naturally yields many of the ingredients required in this context. (orig.)

  15. Leptogenesis in a neutrino mass model coupled with inflaton

    Directory of Open Access Journals (Sweden)

    Daijiro Suematsu

    2016-09-01

    Full Text Available We propose a scenario for the generation of baryon number asymmetry based on the inflaton decay in a radiative neutrino mass model extended with singlet scalars. In this scenario, lepton number asymmetry is produced through the decay of non-thermal right-handed neutrinos caused from the inflaton decay. Since the amount of non-thermal right-handed neutrinos could be much larger than the thermal ones, the scenario could work without any resonance effect for rather low reheating temperature. Sufficient baryon number asymmetry can be generated for much lighter right-handed neutrinos compared with the Davidson–Ibarra bound.

  16. Geometric gravitational origin of neutrino oscillations and mass-energy

    CERN Document Server

    Gonzalez-Martin, Gustavo R

    2012-01-01

    A mass-energy scale for neutrinos was calculated from the null cone curvature using geometric concepts. The scale is variable depending on the gravitational potential and the trajectory inclination with respect to the field direction. The mass-energy at the Earth surface varies from a horizontal value 0.402 eV to a vertical value 0.569 eV. Earth spinor waves with winding numbers n show squared energy differences within ranges from 2.05 x 10*(-3) to 4.10 x 10*(-3) eV*2 for n=0,1 neutrinos and from 6.14 x 10*(-5) to 12.3 x 10*(-5) eV*2 for n=1,2 neutrinos. These waves interfere and the different phase velocities produce neutrino-like oscillations. The experimental results for atmospheric and solar neutrino oscillation mass parameters respectivelly fall within these theoretical ranges. Neutrinos in outer space, where interactions may be neglected, appear as particles travelling with zero mass on null geodesics. These gravitational curvature energies are consistent with neutrino oscillations, zero neutrino rest m...

  17. Disappearing neutrinos at KamLAND suport the case for neutrino mass

    CERN Multimedia

    Johnson, G

    2002-01-01

    Measurements from KamLAND, show that anti-neutrinos emanating from nearby nuclear reactors are "disappearing," which indicates they have mass and can oscillate or change from one type to another (2 pages)

  18. Neutrino Mass and Missing Momentum Higgs Boson Signals

    CERN Document Server

    Díaz, M A; Restrepo, D A; Valle, José W F

    1998-01-01

    In the simplest scheme for neutrino masses invoking a triplet of Higgs scalars there are two CP-even neutral Higgs bosons $H_i$ (i=1,2) and one massive pseudoscalar $A$. For some choices of parameters, the lightest $H_1$ may be lighter than the Standard Model Higgs boson. If the smallness of neutrino mass is due to the small value of the triplet expectation value, as expected in a seesaw scheme, the Higgs bosons may decay dominantly to the invisible neutrino channel. We derive limits on Higgs masses and couplings that follow from LEP I precision measurements of the invisible Z width.

  19. Radiative neutrino mass with scotogenic scalar triplet

    Energy Technology Data Exchange (ETDEWEB)

    Brdar, Vedran; Picek, Ivica; Radovčić, Branimir

    2014-01-20

    We present a radiative one-loop neutrino mass model with hypercharge zero scalar triplet in conjunction with another charged singlet scalar and an additional vectorlike lepton doublet. We study three variants of this mass model: the first one without additional beyond-SM symmetry, the second with imposed DM-stabilizing discrete Z{sub 2} symmetry, and the third in which this Z{sub 2} symmetry is promoted to the gauge symmetry U(1){sub D}. The two latter cases are scotogenic, with a neutral component of the scalar triplet as a dark matter candidate. In first scotogenic model the Z{sub 2}-odd dark matter candidate is at the multi-TeV mass scale, so that all new degrees of freedom are beyond the direct reach of the LHC. In second scotogenic setup, with broken U(1){sub D} symmetry the model may have LHC signatures or be relevant to astrophysical observations, depending on the scale of U(1){sub D} breaking.

  20. Neutrino Physics

    CERN Document Server

    Xing, Zhi-Zhong

    2014-01-01

    I give a theoretical overview of some basic properties of massive neutrinos in these lectures. Particular attention is paid to the origin of neutrino masses, the pattern of lepton flavor mixing, the feature of leptonic CP violation and the electromagnetic properties of massive neutrinos. I highlight the TeV seesaw mechanisms as a possible bridge between neutrino physics and collider physics in the era characterized by the Large Hadron Collider.

  1. Bi-large Neutrino Mixing See-Saw Mass Matrix with Texture Zeros and Leptogenesis

    Institute of Scientific and Technical Information of China (English)

    CHAO Wei; HE Xiao-Gang; LI Xue-Qian

    2006-01-01

    We study constraints on neutrino properties for a class of bi-large mixing See-Saw mass matrices with texture zeros and with the related Dirac neutrino mass matrix to be proportional to a diagonal matrix of the form diag(e, 1, 1). Texture zeros may occur in the light (class a)) or in the heavy (class b)) neutrino mass matrices. Each of these two classes has 5 different forms which can produce non-trivial three generation mixing with at least one texture zero. We find that two types of texture zero mass matrices in both class a and class b can be consistent with present data on neutrino masses and mixing. None of the neutrinos can have zero masses and the lightest of the light neutrinos has a mass larger than about 0.046 eV for class a and 0.0027 eV for class b. In these models although the CKM CP violating phase vanishes, the non-zero Majorana phases can exist and can play an important role in producing the observed baryon asymmetry in our universe through leptogenesis mechanism. The requirement of producing the observed baryon asymmetry can further distinguish different models and also restrict the See-Saw scale to be in the range of 1012 ~ 1015GeV. We also discuss RG effects on V13.

  2. Neutrino masses and mixing from S4 flavor twisting

    CERN Document Server

    Ishimori, Hajime; Tanimoto, Morimitsu; Watanabe, Atsushi

    2010-01-01

    We discuss a neutrino mass model based on the S4 discrete symmetry where the symmetry breaking is triggered by the boundary conditions of the bulk right-handed neutrino in the fifth spacial dimension. While the symmetry restricts bare mass parameters to flavor-diagonal forms, the viable mixing angles emerge from the wave functions of the Kaluza-Klein modes which carry symmetry breaking effect. The magnitudes of the lepton mixing angles, especially the reactor angle is related to the neutrino mass patterns and the model will be tested in future neutrino experiments, e.g., an early (late) discovery of the reactor angle favors the normal (inverted) hierarchy. The size of extra dimension has a connection to the possible mass spectrum; a small (large) volume corresponds to the normal (inverted) mass hierarchy.

  3. Neutrino mass and mixing – status

    Indian Academy of Sciences (India)

    Thomas Schwetz

    2012-11-01

    The status of neutrino oscillations from global data are summarized. An update on the three-flavour picture and recent developments are discussed with regard to the measurement of the mixing angle 13. Global data currently provide an indication at 3 that 13 is non-zero. Furthermore, the status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of MiniBooNE results and a recent re-evaluation of the neutrino fluxes from nuclear reactors are discussed. Despite several hints for sterile neutrinos at the eV scale, there is severe tension in the global data and no consistent description of all data is possible.

  4. Neutrino mass sum rules and symmetries of the mass matrix

    Energy Technology Data Exchange (ETDEWEB)

    Gehrlein, Julia [Karlsruhe Institute of Technology, Institut fuer Theoretische Teilchenphysik, Karlsruhe (Germany); Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Instituto de Fisica Teorica UAM/CSIC, Madrid (Spain); Spinrath, Martin [Karlsruhe Institute of Technology, Institut fuer Theoretische Teilchenphysik, Karlsruhe (Germany); National Center for Theoretical Sciences, Physics Division, Hsinchu (China)

    2017-05-15

    Neutrino mass sum rules have recently gained again more attention as a powerful tool to discriminate and test various flavour models in the near future. A related question which has not yet been discussed fully satisfactorily was the origin of these sum rules and if they are related to any residual or accidental symmetry. We will address this open issue here systematically and find previous statements confirmed. Namely, the sum rules are not related to any enhanced symmetry of the Lagrangian after family symmetry breaking but they are simply the result of a reduction of free parameters due to skillful model building. (orig.)

  5. Neutrino Mass Seesaw at the Weak Scale, the Baryon Asymmetry, and the LHC

    CERN Document Server

    Blanchet, Steve; Mohapatra, Rabindra N

    2008-01-01

    We consider theories where the Standard Model (SM) neutrinos acquire masses through the seesaw mechanism at the weak scale. We show that in such a scenario, the requirement that any pre-existing baryon asymmetry, regardless of its origin, not be washed out leads to correlations between the pattern of SM neutrino masses and the spectrum of new particles at the weak scale, leading to definite predictions for the LHC. For type I seesaw models with a TeV scale Z' coupled to SM neutrinos, we find that for a normal neutrino mass hierarchy, at least one of the right-handed neutrinos must be `electrophobic', decaying with a strong preference into final states with muons and tauons rather than electrons. For inverted or quasi-degenerate mass patterns, on the other hand, we find upper bounds on the mass of at least one right-handed neutrino. In particular, for an inverted mass hierarchy, this bound is 1 TeV, while the corresponding upper limit in the quasi-degenerate case is 300 GeV. Similar results hold in type III se...

  6. Bounds on sterile neutrino mixing for cosmologically interesting mass range

    CERN Document Server

    Nunokawa, H; Rossi, A; Valle, José W F

    1999-01-01

    This talk summarizes our recent work which studied the impact of resonant neutrino) conversions on supernova physics, under the assumption that the mass of the sterile state is in the few eV -cosmologically significant range.

  7. Mass varying neutrinos, symmetry breaking, and cosmic acceleration

    Science.gov (United States)

    Sadjadi, H. Mohseni; Anari, V.

    2017-06-01

    We introduce a new proposal for the onset of cosmic acceleration based on mass varying neutrinos. When massive neutrinos become nonrelativistic, the Z2 symmetry breaks, and the quintessence potential becomes positive from its initially zero value. This positive potential behaves like a cosmological constant at the present era and drives the Universe's acceleration during the slow roll evolution of the quintessence. In contrast to Λ CDM model, the dark energy in our model is dynamical, and the acceleration is not persistent. Contrary to some of the previous models of dark energy with mass varying neutrinos, we do not use the adiabaticity condition, which leads to instability.

  8. Correlations of the elements of the neutrino mass matrix

    CERN Document Server

    Grimus, Walter

    2012-01-01

    Assuming Majorana nature of neutrinos, we re-investigate, in the light of the recent measurement of the reactor mixing angle, the allowed ranges for the absolute values of the elements of the neutrino mass matrix in the basis where the charged-lepton mass matrix is diagonal. Apart from the derivation of upper and lower bounds on the values of the matrix elements, we also study their correlations. Moreover, we analyse the sensitivity of bounds and correlations to the global fit results of the neutrino oscillation parameters which are available in the literature.

  9. Reconstructing the Right-Handed Neutrino Masses in Left-Right Symmetric Theories

    CERN Document Server

    Hosteins, P

    2006-01-01

    We introduce a method to extract the right-handed neutrino mass matrix from the Left-Right symmetric seesaw formula and apply it to the study of a simple SUSY SO(10) theory. We find 8 possible solutions for the heavy neutrino spectrum and a richer phenomenology than in the pure type I or type II seesaw mechanism. Leptogenesis is studied in SO(10) and can be accomodated more easily than with the type I dominance.

  10. Models for neutrino mass and physics beyond standard model

    CERN Document Server

    Ahriche, Amine; Nasri, Salah

    2015-01-01

    In this work, we report on recent analysis of three-loop models of neutrino mass with dark matter. We discuss in detail the model of Krauss-Nasri-Trodden (KNT) [1], showing that it offers a viable solution to the neutrino mass and dark matter problems, and describe observable experimental signals predicted by the model. Furthermore, we show that the KNT model belongs to a larger class of three-loop models that can differ from the KNT approach in interesting ways.

  11. Radiative Neutrino Mass via Both Minimal Dark Matter Candidates

    CERN Document Server

    Ahriche, Amine; Nasri, Salah; Picek, Ivica

    2016-01-01

    We identify a minimal model achieving one-loop radiative neutrino masses due to couplings with dark matter. Interestingly the model contains both the quintuplet fermion and the septuplet scalar identified as minimal dark matter candidates by Cirelli, Fornengo and Strumia - it gives radiative neutrino mass due to both minimal dark matter candidates. The model is related to those proposed in a recent work (dubbed minimal R$\

  12. Neutrino oscillations in the field of a rotating deformed mass

    CERN Document Server

    Geralico, Andrea

    2012-01-01

    The neutrino oscillations in the field of a rotating deformed mass is investigated. The phase shift is evaluated in the case of weak field limit, slow rotation and small deformation. To this aim the Hartle-Thorne metric is used, which is an approximate solution of the vacuum Einstein equations accurate to second order in the rotation parameter $a/M$ and to first order in the mass quadrupole moment $q$. Implications on atmospheric, solar and astrophysical neutrinos are discussed.

  13. The Low-Scale Approach to Neutrino Masses

    Directory of Open Access Journals (Sweden)

    Sofiane M. Boucenna

    2014-01-01

    Full Text Available In this short review we revisit the broad landscape of low-scale SU(3c⊗SU(2L⊗U(1Y models of neutrino mass generation, with view on their phenomenological potential. This includes signatures associated to direct neutrino mass messenger production at the LHC, as well as messenger-induced lepton flavor violation processes. We also briefly comment on the presence of WIMP cold dark matter candidates.

  14. Effects of Environment Dependence of Neutrino Mass versus Solar and Reactor Neutrino Data

    CERN Document Server

    González-Garciá, M C; Zukanovich-Funchal, R

    2006-01-01

    In this work we study the phenomenological consequences of the environment dependence of neutrino mass on solar and reactor neutrino phenomenology. Such dependence can be induced, for example, by Yukawa interactions with a light scalar particle which couples to neutrinos and matter and it is expected, among others, in mass varying neutrino scenarios. Under the assumption of one mass scale dominance, we perform a global analysis of solar and KamLAND neutrino data which depends on 4 parameters: the two standard oscillation parameters, Delta m^2 and tan^2(theta), and two new coefficients, which parameterize the environment dependence of the neutrino mass. We find that, generically, the inclusion of the environment dependent terms does not lead to a very statistically significant improvement on the description of the data in the most favoured MSW LMA (or LMA-I) region. It does, however, substantially improve the fit in the high-Delta m^2 LMA (or LMA-II) region which can be allowed at 98.9% CL. Conversely the anal...

  15. Neutrino Mass Spectrum and Neutrinoless Double $\\beta$ Decay

    CERN Document Server

    Klapdor-Kleingrothaus, H V; Smirnov, Yu A

    2001-01-01

    The relations between the effective Majorana mass of the electron neutrino, $m_{ee}$, responsible for neutrinoless double beta decay, and the neutrino oscillation parameters are considered. We show that for any specific oscillation pattern $m_{ee}$ can take any value (from zero to the existing upper bound) for normal mass hierarchy and it can have a minimum for inverse hierarchy. This means that oscillation experiments cannot fix in general $m_{ee}$. Mass ranges for $m_{ee}$ can be predicted in terms of oscillation parameters with additional assumptions about the level of degeneracy and the type of hierarchy of the neutrino mass spectrum. These predictions for $m_{ee}$ are systematically studied in the specific schemes of neutrino mass and flavor which explain the solar and atmospheric neutrino data. The contributions from individual mass eigenstates in terms of oscillation parameters have been quantified. We study the dependence of $m_{ee}$ on the non-oscillation parameters: the overall scale of the neutrino...

  16. Neutrino masses, dark matter and baryon asymmetry of the Universe

    CERN Document Server

    Ahriche, Amine

    2014-01-01

    In this work, we try to explain the neutrino mass and mixing data radiatively at three-loop by extending the standard model (SM) with two charged singlet scalars and three right handed (RH) neutrinos. Here, the lightest RH neutrino is a dark matter candidate that gives a relic density in agreement with the recent Planck data, the model can be consistent with the neutrino oscillation data, lepton flavor violating processes, the electroweak phase transition can be strongly first order; and the charged scalars may enhance the branching ratio $h\\rightarrow\\gamma\\gamma$, where as $h\\rightarrow\\gamma Z$ get can get few percent suppression. We also discuss the phenomenological implications of the RH neutrinos at the collider.

  17. Neutrino mass calorimetric searches in the MARE experiment

    CERN Document Server

    Nucciotti, A

    2010-01-01

    The international project ``Microcalorimeter Arrays for a Rhenium Experiment'' (MARE) aims at the direct and calorimetric measurement of the electron neutrino mass with sub-electronvolt sensitivity. Calorimetric neutrino mass experiments measure all the energy released in a beta decay except for the energy carried away by the neutrino, therefore removing the most severe systematic uncertainties which have plagued the traditional and, so far, more sensitive spectrometers. Calorimetric measurements are best realized exploiting the thermal detection technique. This approach uses thermal microcalorimeters whose absorbers contain a low transition energy Q beta decaying isotope. To date the two best options are 187Re and 163Ho. While the first beta decays, the latter decays via electron capture, but both have a Q value around 2.5 keV. The potential of using 187Re for a calorimetric neutrino mass experiment has been already demonstrated. On the contrary, no calorimetric spectrum of 163Ho has been so far measured wit...

  18. Top quark as a dark portal and neutrino mass generation

    Energy Technology Data Exchange (ETDEWEB)

    Ng, John N.; Puente, Alejandro de la

    2013-11-25

    We present a new model for radiatively generating Majorana active neutrino masses while incorporating a viable dark matter candidate. This is possible by extending the Standard Model with a single Majorana neutrino endowed with a dark parity, a coloured electroweak-singlet scalar, as well as a coloured electroweak-triplet scalar. Within this framework, the up-type quarks play a special role, serving as a portal for dark matter, and a messenger for neutrino mass generation. We consider three benchmark scenarios where the abundance of dark matter can match the latest experimental results, while generating neutrino masses in the milli-electronvolt range. We show how constraints from lepton flavor violation, in particular the branching fraction of μ→eγ, can place lower bounds on the coupling between our dark matter candidate and top quarks. Furthermore, we show that this coupling can also be constrained using collider data from the Tevatron and the LHC.

  19. Top Quark as a Dark Portal and Neutrino Mass Generation

    CERN Document Server

    Ng, John N

    2013-01-01

    We present a new model for radiatively generating Majorana active neutrino masses while incorporating a viable dark matter candidate. This is possible by extending the Standard Model with a single Majorana neutrino endowed with a dark parity, a colour electroweak singlet scalar, as well as a colour electroweak triplet scalar. Within this framework, the $up$-type quarks play a special role, serving as a portal for dark matter, and a messenger for neutrino mass generation. We consider three benchmark scenarios where the abundance of dark matter can match the latest experimental results, while generating neutrino masses in the milli-electronvolt range. We show how constraints from lepton flavour violation, in particular the branching fraction of $\\mu\\to e\\gamma$, can place lower bounds on the coupling between our dark matter candidate and top quarks. Furthermore, we show that this coupling can also be constrained using collider data from the Tevatron and the LHC.

  20. On the importance of the 1-loop finite corrections to seesaw neutrino masses

    CERN Document Server

    Sierra, D Aristizabal

    2011-01-01

    In the standard seesaw mechanism, finite corrections to the neutrino mass matrix arise from 1-loop self-energy diagrams mediated by a heavy neutrino. We study in detail these corrections and demonstrate that they can be very significant, exceeding in several cases the tree-level result. We consider the normal and inverted hierarchy spectra for light neutrinos and compute the finite corrections to the different elements of the neutrino mass matrix. Special attention is paid to their dependence with the parameters of the seesaw model. Among the cases in which the corrections can be large, we identify the fine-tuned models considered previously in the literature, where a strong cancellation between the different parameters is required to achieve compatibility with the experimental data. As a particular example, we also analyze how these corrections modify the tribimaximal mixing pattern and find that the deviations may be sizable, in particular for $\\theta_{13}$. Finally, we emphasize that due to their large siz...

  1. Neutrino masses and b - $\\tau$ unification in the supersymmetric standard model

    CERN Document Server

    Vissani, F

    1994-01-01

    ABSTRACT: There are several indications that the Majorana masses of the right-handed neutrino components, M_R, are at the intermediate scale: M_R\\sim (10^{10}-10^{12}) GeV or even lighter. The renormalization effects due to large Yukawa couplings of neutrinos from region of momenta M_R \\ltap q \\ltap M_G are studied in the supersymmetric standard model. It is shown that neutrino renormalization effect can increase the m_b/m_\\tau ratio up to (10\\div 15)\\%. This strongly disfavours m_b-m_\\tau unification for low values of \\tan\\beta < 10 especially at large values of \\alpha_s. Lower bounds on M_R and \\tan\\beta from the b-\\tau unification condition were found. The implications of the results to the see-saw mechanism of the neutrino mass generation are discussed.

  2. The mass question: do the elementary particles known as neutrinos have mass?

    CERN Multimedia

    Witten, Edward

    2002-01-01

    "Until recently neutrinos were thought to be massless particles, but scientists have now determined that neutrinos have tiny none-zero masses that measure roughly ten million times smaller than an electron's mass. The research of Klapdor-Kleingrothaus has found that the three types of neutriono have almost identical mass".

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

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Yat-Long; Chu, M.C.; Xu, Jianyi [The Chinese University of Hong Kong, Department of Physics, Shatin (China); Tsui, Ka Ming [University of Tokyo, RCCN, ICRR, Kashiwa, Chiba (Japan); Wong, Chan Fai [Sun Yat-Sen University, Guangzhou (China)

    2016-06-15

    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. (orig.)

  4. Degenerate and Other Neutrino Mass Scenarios and Dark Matter

    CERN Document Server

    Minakata, H

    2001-01-01

    I discuss in this talk mainly three topics related with dark matter motivated neutrino mass spectrum and a generic issue of mass pattern, the normal versus the inverted mass hierarchies. In the first part, by describing failure of a nontrivial potential counter example, I argue that the standard 3 $\

  5. Interference Phase of Mass Neutrinos in Kerr Space-Time

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiu-Ju; WANG Yong-Jiu

    2003-01-01

    Along the geodesic we calculate the interference phase of the mass neutrinos in some special cases. Because of the rotation of the mass resource which induces the gravitational field, the angular momentum per unit mass, a, has a contribution to the phase, which is different from the case in Schwarzschild space-time.

  6. Interference phase of mass neutrino in CM space-time

    Institute of Scientific and Technical Information of China (English)

    Chen Xia; Wang Yong-Jiu

    2009-01-01

    In the gravitational field of central mass with electric and magnetic charges and magnetic moment(CM space-time),this paper calculates the interference phase of mass neutrino along geodesic in the radial direction,and discusses the contribution of the electric and magnetic charges and magnetic moment of the central mass to the phase.

  7. Probing the Neutrino Mass Hierarchy with Super-Kamiokande

    CERN Document Server

    Agarwalla, Sanjib Kumar

    2012-01-01

    We show that a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L \\simeq 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu \\rightarrow nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.

  8. Renormalization of seesaw neutrino masses in the standard model with two-Higgs doublets

    Indian Academy of Sciences (India)

    N Nimai Singh; S Biramani Singh

    2000-02-01

    Using the theoretical ambiguities inherent in the seesaw mechanism, we derive the new analytic expressions for both quadratic and linear seesaw formulae for neutrino masses at low energies, with either up-type quark masses or charged lepton masses. This is possible through full radiative corrections arising out of the renormalizations of the Yukawa couplings, the coefficients of the neutrino-mass-operator in the standard model with two-Higgs doublets, and also the QCD–QED rescaling factors below the top-quark mass scale, at one-loop level. We also investigate numerically the unification of top-- Yukawa couplings at the scale =0.59× 108GeV for a fixed value of tan =58.77, and then evaluate the seesaw neutrino masses which are too large in magnitude to be compatible with the presently available solar and atmospheric neutrino oscillation data. However, if we consider a higher but arbitrary value of =0.59× 1011GeV, the predictions from linear seesaw formulae with charged lepton masses, can accommodate simultaneousely both solar atmospheric neutrino oscillation data.

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

    Science.gov (United States)

    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.

  10. Effect of Non Unitarity on Neutrino Mass Hierarchy determination at DUNE, NO$\

    CERN Document Server

    Dutta, Debajyoti; Roy, Samiran

    2016-01-01

    The neutrino mass ordering is one of the principal unknowns in the neutrino sector. Long baseline neutrino experiments have the potential of resolving this issue as they are sensitive to large matter effects. The superbeam experiment DUNE is one of the most promising candidates to study the neutrino mass hierarchy, along with NO$\

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Confronting the Stochastic Neutrino Mixing Mechanism and the sterile neutrino hypothesis as a solution to the short baseline neutrino anomalies

    CERN Document Server

    Zavanin, E M; de Holanda, P C; Peres, O L G

    2015-01-01

    We compare the solutions to the short baseline neutrino anomaly based on oscillations to sterile neutrinos and the Stochastic Neutrino Mixing Mechanism (SNMM) through an analysis of the present neutrino data. The SNMM suggests worse fits than a 3 + 1 sterile neutrino model, although it cannot be discarded by present data. We propose an experiment to distinguish between both solutions, based on placing a $^8$Li source inside a 5kton-yr detector (like SNO). We studied the sensitivity of such an experiment, which makes it possible to discriminate within $2\\sigma$ the SNMM from the 3+1 sterile hypothesis for some particular values of the relevant parameters in 5 kton-years of running.

  13. Flavor versus mass eigenstates in neutrino asymmetries: implications for cosmology

    Science.gov (United States)

    Barenboim, Gabriela; Kinney, William H.; Park, Wan-Il

    2017-09-01

    We show that, if they exist, lepton number asymmetries (L_α ) of neutrino flavors should be distinguished from the ones (L_i) of mass eigenstates, since Big Bang Nucleosynthesis (BBN) bounds on the flavor eigenstates cannot be directly applied to the mass eigenstates. Similarly, Cosmic Microwave Background (CMB) constraints on the mass eigenstates do not directly constrain flavor asymmetries. Due to the difference of mass and flavor eigenstates, the cosmological constraint on the asymmetries of neutrino flavors can be much stronger than the conventional expectation, but they are not uniquely determined unless at least the asymmetry of the heaviest neutrino is well constrained. The cosmological constraint on L_i for a specific case is presented as an illustration.

  14. Flavor versus mass eigenstates in neutrino asymmetries: implications for cosmology

    CERN Document Server

    Barenboim, Gabriela; Park, Wan-Il

    2016-01-01

    We show that, if they exist, lepton number asymmetries ($L_\\alpha$) of neutrino flavors should be distinguished from the ones ($L_i$) of mass eigenstates, since Big Bang Nucleosynthesis (BBN) bounds on the flavor eigenstates cannot be directly applied to the mass eigenstates. Similarly, Cosmic Microwave Background (CMB) constraints on mass eigenstates do not directly constrain flavor asymmetries. Due to the difference of mass and flavor eigenstates, the cosmological constraint on the asymmetries of neutrino flavors can be much stronger than conventional expectation, but not uniquely determined unless at least the asymmetry of the heaviest neutrino is well constrained. Cosmological constraint on $L_i$ for a specific case is presented as an illustration.

  15. Loop-induced Neutrino Masses: A Case Study

    CERN Document Server

    Geng, Chao-Qiang; Tsai, Lu-Hsing

    2014-01-01

    We study the cocktail model in which the Majorana neutrino masses are generated by the so-called "cocktail" three-loop diagrams with the dark matter particle running in the loops. In particular, we give the correct analytic expressions of the neutrino masses in the model by the detailed calculation of the cocktail diagrams. Based on the reliable numerical calculation of the loop integrals, we explore the parameter space which can give the correct orders of neutrino masses while satisfying other experimental constraints, such as those from the neutrinoless double beta decay, low-energy lepton flavor violation processes, electroweak precision tests, and collider searches. As a result, the large couplings and the large mass difference between the two singly-charged (neutral) scalars are required.

  16. Neutrino Mass, Electron Capture and the Shake-off Contributions

    CERN Document Server

    Faessler, Amand; Simkovic, Fedor

    2016-01-01

    Electron capture can determine the electron neutrino mass, while the beta decay of Tritium measures the electron antineutrino mass and the neutrinoless double beta decay observes the Majorana neutrino mass. Electron capture e. g. on 163Ho plus bound electron to 163Dy* plus neutrino can determine the electron neutrino mass from the upper end of the decay spectrum of the excited Dy*, which is given by the Q-Value minus the neutrino mass. The Dy* states decay by X-ray and Auger electron emissions. The total decay energy is measured in a bolometer. These excitations have been studied by Robertson and by Faessler et al.. In addition the daughter atom Dy can also be excited by moving in the capture process one electron into the continuum. The escape of these continuum electrons is automatically included in the experimental bolometer spectrum. Recently a method developed by Intemann and Pollock was used by DeRujula and Lusignoli for a rough estimate of this shake-off process for "s" wave electrons in capture on 163H...

  17. Unification of Gauge Couplings in Radiative Neutrino Mass Models

    CERN Document Server

    Hagedorn, Claudia; Riad, Stella; Schmidt, Michael A

    2016-01-01

    We investigate the possibility of gauge coupling unification in various radiative neutrino mass models, which generate neutrino masses at one- and/or two-loop level. Renormalization group running of gauge couplings is performed analytically and numerically at one- and two-loop order, respectively. We study three different classes of neutrino mass models: (I) minimal ultraviolet completions of the dimension-7 $\\Delta L=2$ operators which generate neutrino masses at one- and/or two-loop level without and with dark matter candidates, (II) models with dark matter which lead to neutrino masses at one-loop level and (III) models with particles in the adjoint representation of $\\mathrm{SU}(3)$. In class (I), gauge couplings unify in a few models and adding dark matter amplifies the chances for unification. In class (II), about a quarter of the models admit gauge coupling unification. In class (III), none of the models leads to gauge coupling unification. Regarding the scale of unification, we find values between $10...

  18. Constraining bilinear R-parity violation from neutrino masses

    Science.gov (United States)

    Góźdź, Marek; Kamiński, Wiesław A.

    2008-10-01

    We confront the R-parity violating minimal supersymmetric standard model with the neutrino oscillation data. Investigating the 1-loop particle-sparticle diagrams with additional bilinear insertions on the external neutrino lines we construct the relevant contributions to the neutrino mass matrix. A comparison of the so-obtained matrices with the experimental ones assuming normal or inverted hierarchy and taking into account possible CP-violating phases allows to set constraints on the values of the bilinear coupling constants. A similar calculation is presented with the input from the Heidelberg-Moscow neutrinoless double beta decay experiment. We base our analysis on the renormalization group evolution of the minimal supersymmetric standard model parameters which are unified at the grand unified theory scale. Using the obtained bounds we calculate the contributions to the Majorana neutrino transition magnetic moments.

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

    Science.gov (United States)

    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.

  20. Neutrino oscillations in the field of a rotating deformed mass

    Energy Technology Data Exchange (ETDEWEB)

    Geralico, A., E-mail: geralico@icra.it [Physics Department and ICRA, University of Rome “La Sapienza”, I-00185 Rome (Italy); Luongo, O., E-mail: orlando.luongo@roma1.infn.it [Physics Department and ICRA, University of Rome “La Sapienza”, I-00185 Rome (Italy); Institute of Nuclear Science, University of Mexico (Mexico)

    2012-03-12

    The neutrino oscillations in the field of a rotating deformed mass is investigated. The phase shift is evaluated in the case of weak field limit, slow rotation and small deformation. To this aim the Hartle–Thorne metric is used, which is an approximate solution of the vacuum Einstein equations accurate to second order in the rotation parameter a/M and to first order in the mass quadrupole moment q. Implications on atmospheric, solar and astrophysical neutrinos are discussed. -- Highlights: ► We consider neutrino oscillations in the field of a rotating deformed mass. ► We evaluate the phase shift in the case of weak field limit, slow rotation and small deformation. ► Observational implications are discussed.

  1. Two old ways to measure the electron-neutrino mass

    CERN Document Server

    De Rújula, A

    2013-01-01

    Three decades ago, the measurement of the electron neutrino mass in atomic electron capture (EC) experiments was scrutinized in its two variants: single EC and neutrino-less double EC. For certain isotopes an atomic resonance enormously enhances the expected decay rates. The favoured technique, based on calorimeters as opposed to spectrometers, has the advantage of greatly simplifying the theoretical analysis of the data. After an initial surge of measurements, the EC approach did not seem to be competitive. But very recently, there has been great progress on micro-calorimeters and the measurement of atomic mass differences. Meanwhile, the beta-decay neutrino-mass limits have improved by a factor of 15, and the difficulty of the experiments by the cube of that figure. Can the "calorimetric" EC theory cope with this increased challenge? I answer this question affirmatively. In so doing I briefly review the subject and extensively address some persistent misunderstandings of the underlying quantum physics.

  2. Confronting electron and neutrino-nucleus interactions: Can the axial mass anomaly be resolved?

    Science.gov (United States)

    Benhar, Omar

    2014-04-01

    Comparison between electron- and neutrino-nucleus scattering data suggests that the so-called axial mass anomaly — i.e., the large disagreement between the value of the nucleon axial mass extracted from the analysis of neutrino interactions with carbon and oxygen and that obtained from deuteron data — is a manifestation of the difficulties in the interpretation of the flux averaged neutrino cross-sections. In this short review, I discuss the role of reaction mechanisms leading to the excitation of two particle-two hole final states of the target nucleus, which are believed to be responsible for the observed excess of quasielastic events, and argue that taking into account their effect may help to reconcile the sizeably different values of the axial mass reported by the MiniBooNe and NOMAD Collaborations.

  3. Neutrino masses in SU(5) x U(1){sub F} with adjoint flavons

    Energy Technology Data Exchange (ETDEWEB)

    Nardi, Enrico [INFN, Laboratori Nazionali di Frascati, C.P. 13, Frascati (Italy); IFT-UAM/CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Restrepo, Diego; Velasquez, Mauricio [Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia)

    2012-03-15

    We present a SU(5) x U(1){sub F} supersymmetric model for neutrino masses and mixings that implements the seesaw mechanism by means of the heavy SU(2) singlets and triplets states contained in three adjoints of SU(5). We discuss how Abelian U(1){sub F} symmetries can naturally yield non-hierarchical light neutrinos even when the heavy states are strongly hierarchical, and how it can also ensure that R-parity arises as an exact accidental symmetry. By assigning two flavons that break U(1){sub F} to the adjoint representation of SU(5) and assuming universality for all the fundamental couplings, the coefficients of the effective Yukawa and Majorana mass operators become calculable in terms of group theoretical quantities. There is a single free parameter in the model, however, at leading order the structure of the light neutrinos mass matrix is determined in a parameter independent way. (orig.)

  4. Neutrino Oscillation Studies with Reactors

    CERN Document Server

    Vogel, Petr; Zhang, Chao

    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 flavors 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 $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  5. Measuring neutrino mass with radioactive ions in a storage ring

    CERN Document Server

    Lindroos, Mats; Orme, Christopher; Schwetz, Thomas

    2009-01-01

    We propose a method to measure the neutrino mass kinematically using beams of ions which undergo beta decay. The idea is to tune the ion beam momentum so that in most decays, the electron is forward moving with respect to the beam, and only in decays near the endpoint is the electron moving backwards. Then, by counting the backward moving electrons one can observe the effect of neutrino mass on the beta spectrum close to the endpoint. In order to reach sensitivities for $m_\

  6. Three-Loop Neutrino Mass Models at Colliders

    CERN Document Server

    Ahriche, Amine; Nasri, Salah

    2015-01-01

    In this work, we report on recent analyses of a class of models that generate neutrino mass at the three-loop level. We argue that these models offer a viable solution to both the neutrino mass and dark matter problems, without being in conflict with experimental constraints from, e.g. lepton flavor violating processes and the muon anomalous magnetic moment. Furthermore, we describe observable experimental signals predicted by the models and show that they have common signatures that can be probed at both the LHC and ILC.

  7. Baryon asymmetry via leptogenesis in a neutrino mass model with complex scaling

    CERN Document Server

    Samanta, Rome; Roy, Probir; Ghosal, Ambar

    2016-01-01

    Baryogenesis via leptogenesis is investigated in a specific model of light neutrino masses and mixing angles. The latter was proposed on the basis of an assumed complex-extended scaling property of the neutrino Majorana mass matrix $M_\

  8. The next challenge for neutrinos: the mass ordering

    CERN Document Server

    Stanco, Luca

    2016-01-01

    Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long--standing investigation of new physics beyond the Standard Model. This is also supported by the recent change of perspectives in neutrino researches since the discovery period is almost over and we are entering the phase of precise measurements. Despite the limited statistics collected for some variables, the three--flavour neutrino framework seems well strengthening. However some relevant pieces of this framework are still missing. The amount of a possible CP violation phase and the mass ordering are among the most challenging and probably those that will be known in the near future. In this paper we will discuss these two correlated issues and a very recent new statistical method introduced to get reliable results on the mass ordering.

  9. The (3+2) Neutrino Mass Spectrum and Double Chooz

    CERN Document Server

    Bandyopadhyay, Abhijit

    2007-01-01

    The implications of extra sterile neutrinos for the Double Chooz experiment is expounded. The so-called ``3+2'' mass spectrum with 2 sterile neutrinos mixed with the active ones, is still allowed by the global neutrino data including MiniBooNE. We probe its impact on the resultant reactor antineutrino signal at the near and far detector of the Double Chooz experiment. The oscillations driven by the additional mass squared difference due to the sterile states bring an energy independent constant suppression at both the near and far detectors. We study to what extent the measurement of $\\theta_{13}$ would get affected due to the presence of sterile mixing. We also give the projected sensitivity that Double Chooz will have to constrain the extra mixing angles associated with the sterile states.

  10. Conditions for Statistical Determination of the Neutrino Mass Spectrum in Radiative Emission of Neutrino Pairs in Atoms

    CERN Document Server

    Song, Ningqiang; Gomez-Cadenas, J J; Gonzalez-Garcia, M C; Conde, A Peralta; Taron, Josep

    2015-01-01

    The photon spectrum in macrocoherent atomic de-excitation via radiative emission of neutrino pairs (RENP) has been proposed as a sensitive probe of the neutrino mass spectrum, capable of competing with conventional neutrino experiments. In this paper we revisit this intriguing technique in order to quantify the requirements for statistical determination of some of the properties of the neutrino spectrum, in particular the neutrino mass scale and the mass ordering. Our results are sobering. We find that, even under ideal conditions, the determination of neutrino parameters needs experimental live times of the order of days to years for several laser frequencies, assuming a target of volume of order 100 cm3 containing about 10^21 atoms per cubic centimeter in a totally coherent state with maximum value of the electric field in the target. Such conditions seem to be, as of today, way beyond the reach of our current technology.

  11. Absolute neutrino masses physics beyond SM, double beta decay and cosmic rays

    CERN Document Server

    Päs, H; P\\"as, Heinrich; Weiler, Thomas J.

    2002-01-01

    Absolute neutrino masses provide a key to physics beyond the standard model. We discuss the impact of absolute neutrinos masses on physics beyond the standard model, the experimental possibilities to determine absolute neutrinos masses, and the intriguing connection with the Z-burst model for extreme-energy cosmic rays.

  12. Unified understanding of neutrino oscillation and negative mass-square of neutrino

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The author indicates that even a conclusive confirmation of neutrino oscillation does not necessarily imply the existence of massive neutrinos. The negative value of neutrino mass-square may be an alternative key with realistic physical meaning. Reexamining special relativity (SR) we find that there actually exists a formal phase velocity of "de Broglie's wave" in tenporal Lorentz transformation attributed to the intrinsical essence of Minkowski's space. The properties of spacelike interval between two events have already included constrains to describe superluminal motion and SR is compatible with the faster-than-light motion originally in algebraic domain. Pay attention to that the operator representation, p←→ -ih , has just verified for subluminal particles, not for superluminal particles, adhering to de Broglie's coexistence idea between waves and particles, it is possible to deduce a formal two-component Weyl equation to describe any species of free neutrinos with imaginary rest mass, which is equivalent to making use of the Dirac equation for a free spin-1/2 particle with zero rest mass in form.

  13. Improved statistical determination of absolute neutrino masses via radiative emission of neutrino pairs from atoms

    Science.gov (United States)

    Zhang, Jue; Zhou, Shun

    2016-06-01

    The atomic transition from an excited state |e ⟩ to the ground state |g ⟩ by emitting a neutrino pair and a photon, i.e., |e ⟩→|g ⟩+|γ ⟩+|νi⟩+|ν¯j⟩ with i , j =1 , 2, 3, has been proposed by Yoshimura and his collaborators as an alternative way to determine the absolute scale m0 of neutrino masses. More recently, a statistical analysis of the fine structure of the photon spectrum from this atomic process has been performed [N. Song et al. Phys. Rev. D 93, 013020 (2016)] to quantitatively examine the experimental requirements for a realistic determination of absolute neutrino masses. In this paper, we show how to improve the statistical analysis and demonstrate that the previously required detection time can be reduced by one order of magnitude for the case of a 3 σ determination of m0˜0.01 eV with an accuracy better than 10%. Such an improvement is very encouraging for further investigations on measuring absolute neutrino masses through atomic processes.

  14. Counting muons to probe the neutrino mass spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Lujan-Peschard, Carolina [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Universidad de Guanajuato, Departamento de Fisica, DCeI, Leon, Guanajuato (Mexico); Pagliaroli, Giulia [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Vissani, Francesco [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy)

    2013-05-15

    The experimental evidence that {theta} {sub 13} is large opens new opportunities to identify the neutrino mass spectrum. We outline a possibility to investigate this issue by means of conventional technology. The ideal set-up turns out to be long baseline experiment: the muon neutrino beam, with 10{sup 20} protons on target, has an average energy of 6 (8) GeV; the neutrinos, after propagating 6000 (8000) km, are observed by a muon detector of 1 Mton and with a muon energy threshold of 2 GeV. The expected number of muon events is about 1000, and the difference between the two neutrino spectra is sizeable, about 30 %. This allows the identification of the mass spectrum just counting muon tracks. The signal events are well characterized experimentally by their time and direction of arrival, and 2/3 of them are in a region with little atmospheric neutrino background, namely, between 4 GeV and 10 GeV. The distances from CERN to Baikal Lake and from Fermilab to KM3NET, or ANTARES, fit in the ideal range. (orig.)

  15. Limits on $T_{\\rm reh}$ for thermal leptogenesis with hierarchical neutrino masses

    CERN Document Server

    Chankowski, P H

    2003-01-01

    We make a simple observation that if one of the right-chiral neutrinos is very heavy or its Yukawa couplings to the standard lepton doublets are negligible, so that it effectively decouples from the see-saw mechanism, the prediction for the baryon asymmetry of the Universe resulting from leptogenesis depends apart from the masses $M_1$ and $M_2$ of the remaining two right-chiral neutrinos only on the element $\\YY{22}$ of the neutrino Yukawa coupling. For $M_2\\simgt10M_1$ the lower bound on $M_1$ and also on $T_{\\rm reh}$, resulting from the requirement of 'successful leptogenesis' is then significantly increased compared to the one computed recently by Buchm\\"uller {\\it et al.} in the most general case. Within the framework of thermal leptogenesis, the only way to lower this limit is then to allow for sufficiently small mass difference $M_2-M_1$.

  16. The Use of Low Temperature Detectors for Direct Measurements of the Mass of the Electron Neutrino

    Directory of Open Access Journals (Sweden)

    A. Nucciotti

    2016-01-01

    Full Text Available Recent years have witnessed many exciting breakthroughs in neutrino physics. The detection of neutrino oscillations has proved that neutrinos are massive particles, but the assessment of their absolute mass scale is still an outstanding challenge in today particle physics and cosmology. Since low temperature detectors were first proposed for neutrino physics experiments in 1984, there has been tremendous technical progress: today this technique offers the high energy resolution and scalability required to perform competitive experiments challenging the lowest electron neutrino masses. This paper reviews the thirty-year effort aimed at realizing calorimetric measurements with sub-eV neutrino mass sensitivity using low temperature detectors.

  17. The use of low temperature detectors for direct measurements of the mass of the electron neutrino

    CERN Document Server

    Nucciotti, Angelo

    2015-01-01

    Recent years have witnessed many exciting breakthroughs in neutrino physics. The detection of neutrino oscillations has proved that neutrinos are massive particles but the assessment of their absolute mass scale is still an outstanding challenge in today particle physics and cosmology. Since low temperature detectors were first proposed for neutrino physics experiments in 1984, there have been tremendous technical progresses: today this technique offers the high energy resolution and scalability required to perform competitive experiments challenging the lowest electron neutrino masses. This paper reviews the thirty-year effort aimed at realizing a calorimetric measurements with sub-eV neutrino mass sensitivity using low temperature detectors.

  18. Mass neutrino oscillations in Reissner-Nordstrom space-time

    Institute of Scientific and Technical Information of China (English)

    Huang Xiu-Ju; Wang Yong-Jiu

    2004-01-01

    Along the geodesic we calculate the interference phase of the mass neutrinos propagating in the radial direction in the Reissner-Nordstrom field. From the calculation we find that, though there exists electric charge in the gravitational source, the phase increases very little compared with that in the Schwarzschild field.

  19. A New Parametrization of Mass Varying Neutrinos Applied in Supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Rossi-Torres, F.; Guzzo, M.M.; Holanda, P.C. de; Peres, O.L.G. [Instituto de Fisica Gleb Wataghin - UNICAMP, Rua Sergio Buarque de Holanda, 777, 13083-859, Campinas-SP (Brazil)

    2012-08-15

    We propose a phenomenological model of mass varying neutrino (MaVaN) to be applied to supernovae. We consider oscillations of {nu}{sup Macron }{sub e}{yields}{nu}{sup Macron }{sub s} in this MaVaN approach and seek for possible modifications of survival probabilities.

  20. Masses, mélange et oscillations de neutrinos

    CERN Document Server

    Wilquet, Gaston

    The experimental situation concerning the measurements of neutrinos masses, mixing and oscillation is reviewed, as well as of the underlying phenomenology. A particular attention is given to the CERN experimental program to which I took or take part, CHARM-II, CHORUS and OPERA. In the last chapter, I try to put into perspective the medium and long term experimental programme.

  1. A common source for neutrino and sparticle masses

    CERN Document Server

    Brignole, Andrea; Rossi, Anna

    2010-01-01

    We discuss supersymmetric scenarios in which neutrino masses arise from effective d=6 operators in the Kahler potential (including SUSY-breaking insertions). Simple explicit realizations of those Kahler operators are presented in the context of the type II seesaw. An appealing scenario emerges upon identifying the seesaw mediators with SUSY-breaking messengers.

  2. Development of Si microcalorimeters for a neutrino mass experiment

    Energy Technology Data Exchange (ETDEWEB)

    Alessandrello, A. [Milan Univ. (Italy). Dipt. di Fisica; Brofferio, C. [Milan Univ. (Italy). Dipt. di Fisica; Camin, D.V. [Milan Univ. (Italy). Dipt. di Fisica; Cattadori, C. [Milan Univ. (Italy). Dipt. di Fisica; Cavallini, R. [Milan Univ. (Italy). Dipt. di Fisica; Cremonesi, O. [Milan Univ. (Italy). Dipt. di Fisica; Fiorini, E. [Milan Univ. (Italy). Dipt. di Fisica; Giuliani, A. [Milan Univ. (Italy). Dipt. di Fisica; Maglione, A. [IRST, Povo (Italy); Margesin, B. [IRST, Povo (Italy); Nucciotti, A. [Milan Univ. (Italy). Dipt. di Fisica; Parmeggiano, S. [Milan Univ. (Italy). Dipt. di Fisica; Pavan, M. [Milan Univ. (Italy). Dipt. di Fisica; Perego, M. [Milan Univ. (Italy). Dipt. di Fisica; Pessina, G. [Milan Univ. (Italy). Dipt. di Fisica; Pignatel, G. [Trento Univ. (Italy). Dipartimento di Ingegneria dei Materiali; Previtali, E. [Milan Univ. (Italy). Dipt. di Fisica; Sisti, M. [Milan Univ. (Italy). Dipt. di Fisica; Zanotti, L. [Milan Univ. (Italy). Dipt. di Fisica

    1996-02-11

    We are developing high resolution Si-implanted thermistors for a calorimetric neutrino mass experiment. The production process is being tuned to reach high performance and reproducibility. We discuss the properties of devices prepared with different process parameters and different geometries. We also present the results obtained using these thermistors for detecting low energy X-rays. (orig.).

  3. Mossbauer neutrinos in quantum mechanics and quantum field theory

    CERN Document Server

    Kopp, Joachim

    2009-01-01

    We demonstrate the correspondence between quantum mechanical and quantum field theoretical descriptions of Mossbauer neutrino oscillations. First, we compute the combined rate $\\Gamma$ of Mossbauer neutrino emission, propagation, and detection in quantum field theory, treating the neutrino as an internal line of a tree level Feynman diagram. We include explicitly the effect of homogeneous line broadening due to fluctuating electromagnetic fields in the source and detector crystals and show that the resulting formula for $\\Gamma$ is identical to the one obtained previously (Akhmedov et al., arXiv:0802.2513) for the case of inhomogeneous line broadening. We then proceed to a quantum mechanical treatment of Mossbauer neutrinos and show that the oscillation, coherence and resonance terms from the field theoretical result can be reproduced if the neutrino is described as a superposition of Lorentz-shaped wave packet with appropriately chosen energies and widths. On the other hand, the emission rate and the detecti...

  4. Cosmological models with interacting components and mass-varying neutrinos

    CERN Document Server

    Collodel, Lucas G

    2012-01-01

    A model for a homogeneous and isotropic spatially flat Universe, composed of baryons, radiation, neutrinos, dark matter and dark energy is analyzed. We infer that dark energy (considered to behave as a scalar field) interacts with dark matter (either by the Wetterich model, or by the Anderson and Carroll model) and with neutrinos by a model proposed by Brookfield et al.. The latter is understood to have a mass-varying behavior. We show that for a very-softly varying field, both interacting models for dark matter give the same results. The models reproduce the expected red-shift performances of the present behavior of the Universe.

  5. On the Mass Neutrino Phase calculations along the geodesic line and the null line

    OpenAIRE

    Zhang, C. M.; Beesham, A.

    2000-01-01

    On the mass neutrino phase calculations along both the particle geodesic line and the photon null line, there exists a double counting error--factor of 2 when comparing the geodesic phase with the null phase. For the mass neutrino propagation in the flat spacetime, we study the neutrino interference phase calculation in the Minkowski diagram and find that the double counting effect originates from despising the velocity difference between two mass neutrinos. Moreover, we compare the phase cal...

  6. The neutrino mass matrix and (selected) variants of A4

    Indian Academy of Sciences (India)

    Martin Hirsch

    2009-01-01

    Recent neutrino oscillation experiments have measured leptonic mixing angles with considerable precision. Many theoretical attempts to understand the peculiar mixing structure, observed in these measurements, are based on non-Abelian flavour symmetries. This talk concentrates exclusively on models based on the non-Abelian symmetry 4 . 4 is particularly well suited to describe three family mixing, and allows to explain the near tri-bimaximal mixing observed. Special emphasis is put here on the discussion of the neutrinoless double beta decay observable $\\langle m_{} \\rangle$ . Different models based on 4 with very similar predictions for neutrino angles can yield vastly different expectations for $\\langle m_{} \\rangle$ . Neutrinoless double beta decay can thus serve, in principle, as a discriminator between different neutrino mass models.

  7. Study of Two-Loop Neutrino Mass Generation Models

    CERN Document Server

    Geng, Chao-Qiang

    2015-01-01

    We study the models with the Majorana neutrino masses generated radiatively by two-loop diagrams due to the Yukawa $\\rho \\bar \\ell_R^c \\ell_R$ and effective $\\rho^{\\pm\\pm} W^\\mp W^\\mp$ couplings along with a scalar triplet $\\Delta$, where $\\rho$ is a doubly charged singlet scalar, $\\ell_R$ the charged lepton and $W$ the charged gauge boson. A generic feature in these types of models is that the neutrino mass spectrum has to be a normal hierarchy. Furthermore, by using the neutrino oscillation data and comparing with the global fitting result in the literature, we find a unique neutrino mass matrix and predict the Dirac and two Majorana CP phases to be $1.40\\pi$, $1.11\\pi$ and $1.47\\pi$, respectively. We also discuss the model parameters constrained by the lepton flavor violating processes and electroweak oblique parameters. In addition, we show that the rate of the neutrinoless double beta decay $(0\

  8. Status of Heavy Neutrino Experiments

    CERN Document Server

    Wynne, Benjamin; The ATLAS collaboration

    2017-01-01

    The observation of neutrino oscillations raises the possibility that there exist additional, undiscovered high-mass neutrinos, giving mass to Standard Model neutrinos via the seesaw mechanism. By pushing the collider energy frontier at the LHC, the possibility arises that these heavy neutrinos may be produced and identified. We summarise the latest LHC results of searches for heavy neutrinos in a variety of final states.

  9. Oscillating decay rate in electron capture and the neutrino mass difference

    Energy Technology Data Exchange (ETDEWEB)

    Peshkin, Murray

    2015-04-09

    Reported oscillations in the rate of decay of certain ions by K -electron capture have raised questions about whether and how such oscillations can arise in quantum-mechanical theory and whether they can measure the neutrino mass difference. Here I show that simple principles of quantum mechanics answer some questions and clarify what must be performed theoretically or experimentally to answer some others. The principal result is that quantum mechanics does allow mass-difference-dependent oscillations in principle, but it imposes conditions not obeyed by the approximate dynamical models that have been put forth up to now. In particular, indirect coupling between two neutrino mass channels must be taken into account. What needs to be done experimentally and theoretically is discussed.

  10. Oscillating decay rate in electron capture and the neutrino mass difference

    Science.gov (United States)

    Peshkin, Murray

    2015-04-01

    Reported oscillations in the rate of decay of certain ions by K -electron capture have raised questions about whether and how such oscillations can arise in quantum-mechanical theory and whether they can measure the neutrino mass difference. Here I show that simple principles of quantum mechanics answer some questions and clarify what must be performed theoretically or experimentally to answer some others. The principal result is that quantum mechanics does allow mass-difference-dependent oscillations in principle, but it imposes conditions not obeyed by the approximate dynamical models that have been put forth up to now. In particular, indirect coupling between two neutrino mass channels must be taken into account. What needs to be done experimentally and theoretically is discussed.

  11. Probing Models of Dirac Neutrino Masses via the Flavor Structure of the Mass Matrix

    CERN Document Server

    Kanemura, Shinya; Sugiyama, Hiroaki

    2016-01-01

    We classify models of the Dirac neutrino mass by concentrating on flavor structures of the mass matrix. The advantage of our classification is that we do not need to specify detail of models except for Yukawa interactions because flavor structures can be given only by products of Yukawa matrices. All possible Yukawa interactions between leptons (including the right-handed neutrino) are taken into account by introducing appropriate scalar fields. We also take into account the case with Yukawa interactions of leptons with the dark matter candidate. Then, we see that flavor structures can be classified into seven groups. The result is useful for the efficient test of models of the neutrino mass. One of seven groups can be tested by measuring the absolute neutrino mass. Other two can be tested by probing the violation of the lepton universality in $\\ell \\to \\ell^\\prime \

  12. Predicting {theta}{sub 13} and the neutrino mass scale from quark lepton mass hierarchies

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Domcke, V.; Schmitz, K.

    2011-11-15

    Flavour symmetries of Froggatt-Nielsen type can naturally reconcile the large quark and charged lepton mass hierarchies and the small quark mixing angles with the observed small neutrino mass hierarchies and their large mixing angles. We point out that such a flavour structure, together with the measured neutrino mass squared differences and mixing angles, strongly constrains yet undetermined parameters of the neutrino sector. Treating unknown O(1) parameters as random variables, we obtain surprisingly accurate predictions for the smallest mixing angle, sin{sup 2}2{theta}{sub 13}=0.07{sup +0.11}{sub -0.05}, the smallest neutrino mass, m{sub 1}=2.5{sup +1.7}{sub -1.6} x 10{sup -3} eV, and one Majorana phase, {alpha}{sub 21}/{pi}=1.0{sup +0.2}{sub -0.2}. (orig.)

  13. Neutrino-antineutrino Mass Splitting in the Standard Model: Neutrino Oscillation and Baryogenesis

    CERN Document Server

    Fujikawa, Kazuo

    2015-01-01

    By adding a neutrino mass term to the Standard Model, which is Lorentz and $SU(2)\\times U(1)$ invariant but non-local to evade $CPT$ theorem, it is shown that non-locality 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 $\\sim 10^{-20}$ 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 $|m_{K}-m_{\\bar{K}}|<0.44\\times 10^{-18}$ GeV.

  14. Two-loop Induced Majorana Neutrino Mass in a Radiatively Induced Quark and Lepton Mass Model

    CERN Document Server

    Nomura, Takaaki

    2016-01-01

    A two-loop induced radiative neutrino model is proposed as an extension of our previous work in which the first and second generation standard model fermion masses are generated at one-loop level in both quark and lepton sectors. Then we discuss current neutrino oscillation data, lepton flavor violations, muon anomalous magnetic moment, and a bosonic dark matter candidate, for both the normal and inverted neutrino mass hierarchy. Our numerical analysis shows that less hierarchical Yukawa coupling constants can fit the experimental data with TeV scale dark matter.

  15. Do experiments and astrophysical considerations suggest an inverted neutrino mass hierarchy?

    CERN Document Server

    Fuller, G M; Qian, Y Z; Fuller, George M; Primack, Joel R; Qian, Yong Zhong

    1995-01-01

    The recent results from the Los Alamos neutrino oscillation experiment together with assumptions of neutrino oscillation solutions for the solar and atmospheric neutrino deficit problems, may place powerful constraints on any putative scheme for neutrino masses and mixings. Assuming the validity of these experiments and assumptions, we argue that a nearly unique spectrum of neutrino masses emerges as a fit, if two additional astrophysical arguments are adopted: (1) the sum of the light neutrino masses is \\sim 5\\ {\\rm eV}, as large scale structure simulations with mixed cold plus hot dark matter seem to suggest; and (2) r-process nucleosynthesis originates in neutrino-heated ejecta from Type II supernovae. In this fit, the masses of the neutrinos must satisfy m_{{\

  16. Measuring the Mass Hierarchy with Muon and Hadron Events in Atmospheric Neutrino Experiments

    CERN Document Server

    Ghosh, Anushree

    2013-01-01

    Neutrino mass hierarchy can be measured in atmospheric neutrino experiments through the observation of earth matter effects. Magnetized iron calorimeters have been shown to be good in this regard due to their charge identification capabilities. The charged current interaction of $\

  17. Leptogenesis beyond the limit of hierarchical heavy neutrino masses

    CERN Document Server

    Blanchet, S; Blanchet, Steve; Bari, Pasquale Di

    2006-01-01

    We calculate the baryon asymmetry of the Universe in thermal leptogenesis beyond the usual lightest right-handed (RH) neutrino dominated scenario (N_1DS) and in particular beyond the hierarchical limit (HL), M_1 << M_2 << M_3, for the RH neutrino mass spectrum. After providing some orientation among the large variety of models, we first revisit the central role of the N_1DS, with new insights on the dynamics of the asymmetry generation and then discuss the main routes departing from it, focusing on models beyond the HL. We study in detail two examples of `strong-strong' wash-out scenarios: one with `maximal phase' and the limit of very large M_3, studying the effects arising when delta_2=(M_2-M_1)/M_1 is small. We extend analytical methods already applied to the N_1DS showing, for example, that, in the degenerate limit (DL), the efficiency factors of the RH neutrinos become equal with the single decay parameter replaced by the sum. Both cases disprove the misconception that close RH neutrino masse...

  18. Neutrinoless double $\\beta$ decay with small neutrino masses

    CERN Document Server

    del Águila, F; Bhattacharya, S; Santamaria, A; Wudka, J

    2013-01-01

    If the only contribution to neutrinoless double beta decay (NLDBD) are neutrino masses its discovery may be very difficult, especially if neutrinos present a normal hierarchy spectrum. However, this is not the only possibility; NLDBD can in general produce electrons of either chirality, in contrast with the neutrino induced NLDBD which predicts two left-handed electrons. Using an effective Lagrangian approach we classify the lepton number violating (LNV) effective operators with two leptons of either chirality but no quarks, ordered according to the magnitude of their contribution to NLDBD. We point out that, for each of the three chirality assignments, $e_{L}e_{L},e_{L}e_{R}$ and $e_{R}e_{R}$, there is only one LNV operator of the corresponding type to lowest order, and these have dimensions 5, 7 and 9, respectively. Neutrino masses are always induced by these extra operators but can be delayed to one (dimension 7) or two loops (dimension 9). Under the assumption that NLDBD is dominated by the operators of d...

  19. Ultra-low Q values for neutrino mass measurements

    CERN Document Server

    Kopp, Joachim

    2009-01-01

    We investigate weak nuclear decays with extremely small kinetic energy release (Q value) and thus extremely good sensitivity to the absolute neutrino mass scale. In particular, we consider decays into excited daughter states, and we show that partial ionization of the parent atom can help to tune Q values to << 1 keV. We discuss several candidate isotopes undergoing beta+, beta-, bound state beta, or electron capture decay, and come to the conclusion that a neutrino mass measurement using low-Q decays might only be feasible if no ionization is required, and if future improvements in isotope production technology, nuclear mass spectroscopy, and atomic structure calculations are possible. Experiments using ions, however, are extremely challenging due to the large number of ions that must be stored. New precision data on nuclear excitation levels could help to identify further isotopes with low-Q decay modes and possibly less challenging requirements.

  20. Measuring neutrino masses with a future galaxy survey

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Wong, Yvonne Y. Y.

    2012-01-01

    that the minimum mass sum of sum m_nu ~ 0.06 eV in the normal hierarchy can be detected at 1.5 sigma to 2.5 sigma significance, depending on the model complexity, using a combination of galaxy and cosmic shear power spectrum measurements in conjunction with CMB temperature and polarisation observations from Planck....... With better knowledge of the galaxy bias, the significance of the detection could potentially reach 5.4 sigma. Interestingly, neither Planck+shear nor Planck+galaxy alone can achieve this level of sensitivity; it is the combined effect of galaxy and cosmic shear power spectrum measurements that breaks...... the persistent degeneracies between the neutrino mass, the physical matter density, and the Hubble parameter. Notwithstanding this remarkable sensitivity to sum m_nu, Euclid-like shear and galaxy data will not be sensitive to the exact mass spectrum of the neutrino sector; no significant bias (sigma...

  1. Neutrinos from type-II supernovae and the neutrino-driven supernova mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Janka, H.T. [Max-Planck-Institut fuer Astrophysik, Garching (Germany)

    1996-11-01

    Supernova 1987A has confirmed fundamental aspects of our theoretical view of type-II supernovae: Type-II supernovae are a consequence of the collapse of the iron core of a massive evolved star and lead to the formation of a neutron star or black hole. This picture is most strongly supported by the detection of electron antineutrinos in the IMB and Kamiokande II experiments in connection with SN 1987A. However, the mechanism causing the supernova explosion is not yet satisfactorily understood. In this paper the properties of the neutrino emission from supernovae and protoneutron stars will be reviewed; analytical estimates will be derived and results of numerical simulations will be shown. It will be demonstrated that the spectral distributions of the emitted neutrinos show clear and systematic discrepancies compared with thermal (black body-type) emission. This must be taken into account when neutrino observations from supernovae are to be interpreted, or when implications of the neutrino emission on nucleosynthesis processes in mantle and envelope of the progenitor star are to be investigated. Furthermore, the influence of neutrinos on the supernova dynamics will be discussed, in particular their crucial role in causing the explosion by Wilson`s neutrino-driven delayed mechanism. Possible implications of convection inside the newly born neutron star and between surface and the supernova shock will be addressed and results of multi-dimensional simulations will be presented. (author) 7 figs., 1 tab., refs.

  2. Degenerate spectrum in the neutrino mass anarchy with Wishart matrices and implications for $0\

    CERN Document Server

    Jeong, Kwang Sik; Takahashi, Fuminobu

    2014-01-01

    We show that a degenerate neutrino mass spectrum can be realized in the neutrino mass anarchy hypothesis, if the neutrino Yukawa and right-handed neutrino mass matrices are given by the Wishart matrix, i.e. products of $N \\times 3$ rectangular random matrices, whose eigenvalue distribution approaches the Marchenko-Pastur distribution for large $N$. The mixing angle and CP phase distributions are determined by either the Haar measure of U(3) or that of SO(3). We study how large $N$ can be without tension with the observed neutrino mass squared differences, and find that the predicted value of $m_{ee}$ is likely within the reach of future $0\

  3. Sterile Neutrinos, Dominant Seesaw Mechanisms, Double Beta Decay, and Other Predictions

    CERN Document Server

    Parida, M K

    2016-01-01

    In a recent review Mohapatra has discussed how type-I seesaw mechanism suppressed by fine tuning of Yukawa cpuplings, or specific textures of associated fermion mass matrices, can form the basis of neutrino masses in TeV scale $W_R$ boson models. In this paper we review recent works in another class of theories where the added presence of fermion singlets manifesting as sterile neutrinos render the type-I seesaw contribution vanishing but extended seesaw dominant where the light neutrino mass formula is same as the inverse seesaw but all massive neutrinos are Majorana fermions. We discuss how this cancellation criteria has led to a new mechanism of type-II seesaw dominance which also permits $U(1)_{B-L}$ breaking scale much smaller than the left-handed triplet mass and accessible to direct experimental tests. Out of a number of new observable predictions, the most visible one in both cases is the dominant contribution to double beta decay mediated by light sterile neutrinos in the $W_L-W_L$ channel. This sees...

  4. Born–Infeld condensate as a possible origin of neutrino masses and dark energy

    Directory of Open Access Journals (Sweden)

    Andrea Addazi

    2016-09-01

    Full Text Available We discuss the possibility that a Born–Infeld condensate coupled to neutrinos can generate both neutrino masses and an effective cosmological constant. In particular, an effective field theory is provided capable of dynamically realizing the neutrino superfluid phase firstly suggested by Ginzburg and Zharkov. In such a case, neutrinos acquire a mass gap inside the Born–Infeld ether forming a long-range Cooper pair. Phenomenological implications of the approach are also discussed.

  5. Born-Infeld condensate as a possible origin of neutrino masses and dark energy

    CERN Document Server

    Addazi, Andrea; Odintsov, Sergei

    2016-01-01

    We discuss the possibility that a Born-Infeld condensate coupled to neutrinos can generate both neutrino masses and an effective cosmological constant. In particular, an effective field theory is provided capable of dynamically realizing the neutrino superfluid phase firstly suggested by Ginzburg and Zharkov. In such a case, neutrinos acquire a mass gap inside the Born-Infeld ether forming a long-range Cooper pair. Phenomenological implications of the approach are also discussed.

  6. Probing neutrino masses and tri-bimaximality with lepton flavor violation searches

    CERN Document Server

    Kojima, Kentaro

    2009-01-01

    We examine relation between neutrino oscillation parameters and prediction of lepton flavor violation, in light of deviations from tri-bimaximal mixing. Our study shows that upcoming experimental searches for lepton flavor violation process can provide useful implications for neutrino mass spectrum and mixing angles. With simple structure of heavy right-handed neutrino and supersymmetry breaking sectors, the discovery of tau \\to mu gamma decay determines neutrino mass hierarchy if large (order 0.1) reactor angle is established.

  7. Neutrinos

    CERN Document Server

    de Gouvea, A; Scholberg, K; Zeller, G P; Alonso, J; Bernstein, A; Bishai, M; Elliott, S; Heeger, K; Hoffman, K; Huber, P; Kaufman, L J; Kayser, B; Link, J; Lunardini, C; Monreal, B; Morfin, J G; Robertson, H; Tayloe, R; Tolich, N; Abazajian, K; Akiri, T; Albright, C; Asaadi, J; Babu, K S; Balantekin, A B; Barbeau, P; Bass, M; Blake, A; Blondel, A; Blucher, E; Bowden, N; Brice, S J; Bross, A; Carls, B; Cavanna, F; Choudhary, B; Coloma, P; Connolly, A; Conrad, J; Convery, M; Cooper, R L; Cowen, D; da Motta, H; de Young, T; Di Lodovico, F; Diwan, M; Djurcic, Z; Dracos, M; Dodelson, S; Efremenko, Y; Ekelof, T; Feng, J L; Fleming, B; Formaggio, J; Friedland, A; Fuller, G; Gallagher, H; Geer, S; Gilchriese, M; Goodman, M; Grant, D; Gratta, G; Hall, C; Halzen, F; Harris, D; Heffner, M; Henning, R; Hewett, J L; Hill, R; Himmel, A; Horton-Smith, G; Karle, A; Katori, T; Kearns, E; Kettell, S; Klein, J; Kim, Y; Kim, Y K; Kolomensky, Yu; Kordosky, M; Kudenko, Yu; Kudryavtsev, V A; Lande, K; Lang, K; Lanza, R; Lau, K; Lee, H; Li, Z; Littlejohn, B R; Lin, C J; Liu, D; Liu, H; Long, K; Louis, W; Luk, K B; Marciano, W; Mariani, C; Marshak, M; Mauger, C; McDonald, K T; McFarland, K; McKeown, R; Messier, M; Mishra, S R; Mosel, U; Mumm, P; Nakaya, T; Nelson, J K; Nygren, D; Gann, G D Orebi; Osta, J; Palamara, O; Paley, J; Papadimitriou, V; Parke, S; Parsa, Z; Patterson, R; Piepke, A; Plunkett, R; Poon, A; Qian, X; Raaf, J; Rameika, R; Ramsey-Musolf, M; Rebel, B; Roser, R; Rosner, J; Rott, C; Rybka, G; Sahoo, H; Sangiorgio, S; Schmitz, D; Shrock, R; Shaevitz, M; Smith, N; Smy, M; Sobel, H; Sorensen, P; Sousa, A; Spitz, J; Strauss, T; Svoboda, R; Tanaka, H A; Thomas, J; Tian, X; Tschirhart, R; Tully, C; Van Bibber, K; Van de Water, R G; Vahle, P; Vogel, P; Walter, C W; Wark, D; Wascko, M; Webber, D; Weerts, H; White, C; White, H; Whitehead, L; Wilson, R J; Winslow, L; Wongjirad, T; Worcester, E; Yokoyama, M; Yoo, J; Zimmerman, E D

    2013-01-01

    This document represents the response of the Intensity Frontier Neutrino Working Group to the Snowmass charge. We summarize the current status of neutrino physics and identify many exciting future opportunities for studying the properties of neutrinos and for addressing important physics and astrophysics questions with neutrinos.

  8. Neutrino Mass and Dark Energy from Weak Lensing

    CERN Document Server

    Abazajian, Kevork N; Abazajian, Kevork; Dodelson, Scott

    2003-01-01

    Weak gravitational lensing directly probes the mass distribution in the universe. This distribution, and its evolution at late times, is sensitive to both the dark energy and neutrino mass. We examine the potential of lensing experiments to measure features of both simultaneously. Focusing on the radial information contained in a future deep 4000 square degree survey, we find that if the dark energy is fixed to be a cosmological constant (equation of state w=-1) and its density is known, then the expected (1-sigma) error on a neutrino mass is 0.02 eV. If the dark energy parameters are allowed to vary, then the expected error is 0.12 eV. The constraints on dark energy parameters are similarly restrictive, with errors on w of 0.01 if the two other parameters (neutrino mass and dark energy density) are held fixed, and 0.094 if the other parameters are allowed to vary. Much of the restrictive power on the dark energy comes not from the evolution of the gravitational potential but rather from how distances vary as...

  9. An Investigation of Neutrino-Driven Convection and the Core Collapse Supernova Mechanism Using Multigroup Neutrino Transport

    CERN Document Server

    Mezzacappa, A; Bruenn, S W; Blondin, J M; Guidry, M W; Strayer, M R; Umar, A S

    1996-01-01

    We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an ``optimistic'' 15 solar mass precollapse model, which is representative of the class of stars with compact iron cores. This model is evolved through core collapse and bounce in one dimension using multigroup (neutrino-energy--dependent) flux-limited diffusion (MGFLD) neutrino transport and Lagrangian hydrodynamics, providing realistic initial conditions for the postbounce convection and evolution. Our two-dimensional simulation begins at 106 ms after bounce at a time when there is a well-developed gain region, and proceeds for 400 ms. We couple two-dimensional (PPM) hydrodynamics to one-dimensional MGFLD neutrino transport. At 225 ms after bounce we see large-scale convection behind the shock, characterized by high-entropy, mushroom-like, expanding upflows and dense, low-entropy, finger-like downflows. The upflows reach the shock and distort it from sphericity. The radial c...

  10. THE ROLE OF QUANTUM MECHANICS IN NEUTRINO FACTORIES.

    Energy Technology Data Exchange (ETDEWEB)

    GALLARDO,J.C.; SESSLER,A.M.; WURTELE,J.

    2000-12-06

    A compilation is made of the various ways in which quantum phenomena enter into the design and operation of a neutrino factory. They include production of pions, decay of pions into muons, ionization energy loss of muons in material, scattering and energy straggling of muons in material, polarization of muons, and the decay of muons into neutrinos, and the radiation effect of neutrinos. For each process formulas are presented which cover the basic mechanism. A discussion is presented of the areas of uncertainty and of the experiments, underway and proposed, which will reduce the uncertainty to an acceptable level.

  11. 7 keV sterile neutrino dark matter from split flavor mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Hiroyuki [Tohoku Univ., Sendai (Japan). Dept. of Physics; Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

    2014-02-15

    The recently discovered X-ray line at about 3.5 keV can be explained by sterile neutrino dark matter with mass, m{sub s}≅ 7 keV, and the mixing, sin{sup 2}2θ∝10{sup -10}. Such sterile neutrino is more long-lived than estimated based on the seesaw formula, which strongly suggests an extra flavor structure in the seesaw sector. We show that one can explain both the small mass and the longevity based on the split flavor mechanism where the breaking of flavor symmetry is tied to the breaking of the B-L symmetry. In a supersymmetric case we find that the 7 keV sterile neutrino implies the gravitino mass about 100 TeV.

  12. Measuring Neutrino Mass with Radioactive Ions in a Storage Ring

    Science.gov (United States)

    Lindroos, Mats; McElrath, Bob; Orme, Christopher; Schwetz, Thomas

    2010-03-01

    A method to measure the neutrino mass kinematically using beams of ions which undergo beta decay is proposed. The idea is to tune the ion beam momentum so that in most decays, the electron is forward moving with respect to the beam, and only in decays near the endpoint is the electron moving backwards. By counting the backward moving electrons one can observe the effect of neutrino mass on the beta spectrum close to the endpoint. In order to reach sensitivities for mν<0.2 eV, it is necessary to control the ion momentum with a precision better than δp/p<10-5, identify suitable nuclei with low Q-values (in the few to ten keV range), and one must be able to observe at least O(1018) decays.

  13. WIMP dark matter as radiative neutrino mass messenger

    CERN Document Server

    Hirsch, M; Morisi, S; Palacio, J; Rojas, N; Valle, J W F

    2013-01-01

    The minimal seesaw extension of the Standard SU(3) x SU(2) x U(1) 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 (WIMP) 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.

  14. Radiative neutrino mass generation from WIMP dark matter

    CERN Document Server

    Lineros, Roberto A

    2016-01-01

    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 potentially detectable at present and near future collider experiments.

  15. Running Neutrino Mass Parameters in See-Saw Scenarios

    CERN Document Server

    Antusch, S; Lindner, Manfred; Ratz, M; Schmidt, M A; Antusch, Stefan; Kersten, Joern; Lindner, Manfred; Ratz, Michael; Schmidt, Michael Andreas

    2005-01-01

    We systematically analyze quantum corrections in see-saw scenarios, including effects from above the see-saw scales. We derive approximate renormalization group equations for neutrino masses, lepton mixings and CP phases, yielding an analytic understanding and a simple estimate of the size of the effects. Even for hierarchical masses, they often exceed the precision of future experiments. Furthermore, we provide a software package allowing for a convenient numerical renormalization group analysis, with heavy singlets being integrated out successively at their mass thresholds. We also discuss applications to model building and related topics.

  16. Sneutrino-antisneutrino mixing and neutrino mass in anomaly-mediated supersymmetry breaking scenario.

    Science.gov (United States)

    Choi, Kiwoon; Hwang, Kyuwan; Song, Wan Young

    2002-04-01

    In supersymmetric models with nonzero Majorana neutrino mass, the sneutrino and antisneutrino mix, which may lead to same-sign dilepton signals in future collider experiments. We point out that the anomaly-mediated supersymmetry breaking scenario has a good potential to provide an observable rate of such signals for the neutrino masses suggested by the atmospheric and solar neutrino oscillations. It is noted also that the sneutrino-antisneutrino mixing can provide much stronger information on some combinations of the neutrino masses and mixing angles than the neutrino experiments.

  17. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Kwang-Chang [Center for General Education, Chang Gung University,Kwei-Shan, Taoyuan, 333, Taiwan (China); Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Lee, Fei-Fan [Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lee, Feng-Shiuh [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lin, Guey-Lin [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Liu, Tsung-Che [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Yang, Yi [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China)

    2016-07-22

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(ν-bar)+p→ν(ν-bar)+p, and inverse beta decays (IBD), ν-bar{sub e}+p→n+e{sup +}, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of ν-bar{sub e} flux with the ν-bar{sub x} (x=μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

  18. Majorana ghosts: From topological superconductor to the origin of neutrino masses, three generations and their mass mixing

    CERN Document Server

    Gu, Zheng-Cheng

    2013-01-01

    A cutting-edge step towards understanding the nature of neutrino has been taken by the experimental discovery of neutrino mass mixing during the past decade, which indicates neutrino has a small but non-vanishing mass. A natural way to explain the origin of this small mass is the so-called seesaw mechanism, which requires the neutrino to be a Majorana fermion. Recently, Majorana's spirit returns in modern condensed matter physics -- in the context of Majorana zero modes in certain classes of topological superconductors(TSCs). In this paper, we assume a relativistic Majorana fermion is made up of four Majorana zero modes. We begin with an exactly solvable 1D DIII class TSC and show that the pair of Majorana zero modes on each end will realize a T^4=-1 representation of the time reversal symmetry and carry 1/4 spin. We find that a pair of Majorana zero modes can realize a P^4=-1 parity symmetry and even a \\bar C^4=-1 nontrivial charge conjugation symmetry. We then point out that the nontrivial charge conjugatio...

  19. Mass neutrino oscillations in Robertson-Walker space-time

    Institute of Scientific and Technical Information of China (English)

    Huang Xiu-Ju; Li Ze-Jun; Wang Yong-Jiu

    2006-01-01

    Along the geodesic we calculate the interference phase of the mass neutrinos propagating in the radial direction in Robertson-Walker space-time. Since our universe is expanding, the phase factor Φ is increasing under the condition of the same proper physical distance l. Different values of curvature parameter k in Robertson-Walker metric represent different cosmological models, correspondingly, we obtain the different interference phases.

  20. Predictive flavour symmetries of the neutrino mass matrix

    CERN Document Server

    Hirsch, M; Kaneko, S; Valle, J W F; Joshipura, Anjan S.

    2007-01-01

    Here we propose an $A_4$ flavour symmetry model which implies a lower bound on the neutrinoless double beta decay rate, corresponding to an effective mass parameter $M_{ee} \\gsim 0.03$ eV, and a direct correlation between the expected magnitude of CP violation in neutrino oscillations and the value of $\\sin^2\\theta_{13}$, as well as a nearly maximal CP phase $\\delta$.

  1. Mirror matter, inverse seesaw neutrino masses and the Higgs mass spectrum

    CERN Document Server

    Candido, M M; Malta, P C; Simões, J A Martins; Ramalho, A J

    2011-01-01

    In this work we study a mirror model with inverse seesaw neutrino masses in which symmetry breaking scales are fixed from bounds in the neutrino sector. The Higgs sector of the model has two doublets and neutral singlets. The mirror model can be tested at the LHC energies in several aspects. Two very distinctive signatures of the mirror model are a new neutral gauge boson $Z^{\\prime}$, with a high invisible branching ratio, and a heavy Majorana neutrino production through the decay $Z^{\\prime} \\rightarrow N +\\bar \

  2. Probing neutrino masses with future galaxy redshift surveys

    CERN Document Server

    Lesgourgues, Julien; Perotto, Laurence; Lesgourgues, Julien; Pastor, Sergio; Perotto, Laurence

    2004-01-01

    We perform a new study of future sensitivities of galaxy redshift surveys to the free-streaming effect caused by neutrino masses, adding the information on cosmological parameters from measurements of primary anisotropies of the cosmic microwave background (CMB). Our reference cosmological scenario has nine parameters and three different neutrino masses, with a hierarchy imposed by oscillation experiments. Within the present decade, the combination of the Sloan Digital Sky Survey (SDSS) and CMB data from the PLANCK experiment will have a 2-sigma detection threshold on the total neutrino mass close to 0.2 eV. This estimate is robust against the inclusion of extra free parameters in the reference cosmological model. On a longer term, the next generation of experiments may reach values of order sum m_nu = 0.1 eV at 2-sigma, or better if a galaxy redshift survey significantly larger than SDSS is completed. We also discuss how the small changes on the free-streaming scales in the normal and inverted hierarchy sche...

  3. Bounds for the mass of the heaviest right-handed neutrino in SO(10) theories

    CERN Document Server

    Buccella, F

    2003-01-01

    By relating the Dirac neutrino mass matrix to the mass of the charged fermions and assuming that the product of the masses of the two lightest left-handed neutrinos is of the order of $\\Delta m^2_{sol}$, we derive, within a leptogenesis scenario, a range of values for the mass of the heaviest right-handed neutrino, centered around the scale of $B-L$ symmetry breaking in the SO(10) theory with Pati-Salam intermediate symmetry.

  4. Probing Models of Neutrino Masses via the Flavor Structure of the Mass Matrix

    CERN Document Server

    Kanemura, Shinya

    2015-01-01

    We discuss what kinds of combinations of Yukawa interactions can generate the Majorana neutrino mass matrix. We concentrate on the flavor structure of the neutrino mass matrix because it does not depend on details of the models except for Yukawa interactions while determination of the overall scale of the mass matrix requires to specify also the scalar potential and masses of new particles. Thus, models to generate Majorana neutrino mass matrix can be efficiently classified according to the combination of Yukawa interactions. We first investigate the case where Yukawa interactions with only leptons are utilized. Next, we consider the case with Yukawa interactions between leptons and gauge singlet fermions, which have the odd parity under the unbroken Z_2 symmetry. We show that combinations of Yukawa interactions for these cases can be classified into only three groups. Our classification would be useful for the efficient discrimination of models via experimental tests for not each model but just three groups ...

  5. 170th International School of Physics "Enrico Fermi" : Measurements of Neutrino Mass

    CERN Document Server

    Vissani, F; Brofferio, C; MNM-08; Measurements of Neutrino Mass; MNM 2008

    2009-01-01

    This volume offers a valuable insight into various aspects of the ongoing work directed at measuring neutrino mass. It took twenty years to refute the assertions of Bethe and Peierls that neutrinos were not observable, but it has since been realised that much can be learnt from these particles. The moral is, as Fiorini argues here, that the study of neutrinos was and remains demanding but rewarding. Subjects addressed in this volume include; clarifying the meaning of the Klapdor-Kleingrothaus results, probing the Majorana nature of neutrinos, observing lepton number violating effects for the first time, studying the end point of the spectrum in the search for neutrino masses and speculating whether it is possible to measure neutrino masses in cosmology. Lectures are enriched with rich historical overviews and valuable introductory material. Attention is also given to theoretical topics such as the evolution of the concept of mass in particle physics, a status report on neutrino oscillations and current discus...

  6. Gamma ray bursts as probes of neutrino mass, quantum gravity and dark energy

    CERN Document Server

    Choubey, S; Choubey, Sandhya

    2003-01-01

    We calculate the time delays of neutrinos emitted in gamma ray bursts due to the effects of neutrino mass and quantum gravity using a time dependent Hubble constant which can significantly change the naive results presented hitherto in the literature for large redshifts, and gives some sensitivity to the details of dark energy. We show that the effects of neutrino mass, quantum gravity and dark energy may be disentangled by using low energy neutrinos to study neutrino mass, high energy neutrinos to study quantum gravity, and large redshifts to study dark energy. From low energy neutrinos one may obtain direct limits on neutrino masses of order 10^{-3} eV, and distinguish a neutrino mass hierarchy from an inverted mass hierarchy. From ultra-high energy neutrinos the sensitivity to the scale of quantum gravity can be pushed up to E_{QG} ~ 5 X 10^{30} GeV. By studying neutrinos from GRBs at large redshifts a cosmological constant could be distinguished from quintessence.

  7. The Neutrino Bubble Instability: A Mechanism for Generating Pulsar Kicks

    CERN Document Server

    Socrates, A; Hungerford, A; Fryer, C L; Socrates, Aristotle; Blaes, Omer; Hungerford, Aimee; Fryer, Chris L.

    2004-01-01

    An explanation for the large random velocities of pulsars is presented. Like many other models, we propose that the momentum imparted to the star is given at birth. The ultimate source of energy is provided by the intense optically thick neutrino flux that is responsible for radiating the proto-neutron star's gravitational binding energy during the Kelvin-Helmholtz phase. The central feature of the kick mechanism is a radiative-driven magnetoacoustic instability, which we refer to as ``neutrino bubbles.'' Identical in nature to the photon bubble instability, the neutrino bubble instability requires the presence of an equilibrium radiative flux as well as a coherent steady background magnetic field. Over regions of large magnetic flux densities, the neutrino bubble instability is allowed to grow on dynamical timescales ~ 1ms, potentially leading to large luminosity enhancements and density fluctuations. Local luminosity enhancements, which preferentially occur over regions of strong magnetic field, lead to a n...

  8. A Radiative Model for the Weak Scale and Neutrino Mass via Dark Matter

    CERN Document Server

    Ahriche, Amine; Nasri, Salah

    2015-01-01

    We present a three-loop model of neutrino mass in which both the weak scale and neutrino mass arise as radiative effects. In this approach, the scales for electroweak symmetry breaking, dark matter, and the exotics responsible for neutrino mass, are related due to an underlying scale-invariance. This motivates the otherwise-independent O(TeV) exotic masses usually found in three-loop models of neutrino mass. We demonstrate the existence of viable parameter space and show that the model can be probed at colliders, precision experiments, and dark matter direct-detection experiments.

  9. Global Analysis of the post-SNO Solar Neutrino Data for Standard and Non-Standard Oscillation Mechanisms

    CERN Document Server

    Gago, A M; De Holanda, P C; Nunokawa, H; Peres, O L G; Pleitez, V; Zukanovich-Funchal, R

    2002-01-01

    What can we learn from solar neutrino observations? Is there any solution to the solar neutrino anomaly which is favored by the present experimental panorama? After SNO results, is it possible to affirm that neutrinos have mass? In order to answer such questions we analyze the current available data from the solar neutrino experiments, including the recent SNO result, in view of many acceptable solutions to the solar neutrino problem based on different conversion mechanisms, for the first time, using the same statistical procedure. This allows us to do a direct comparison of the goodness of the fit among different solutions, from which we can discuss and conclude on the current status of each proposed dynamical mechanism. These solutions are based on different assumptions: (a) neutrino mass and mixing, (b) non-vanishing neutrino magnetic moment, (c) the existence of non-standard flavor-changing and non-universal neutrino interactions and (d) the tiny violation of the equivalence principle. We investigate the ...

  10. Neutrino mass, mixing and discrete symmetries

    CERN Document Server

    Smirnov, Alexei Y

    2013-01-01

    Status of the discrete symmetry approach to explanation of the lepton masses and mixing is summarized in view of recent experimental results, in particular, establishing relatively large 1-3 mixing. The lepton mixing can originate from breaking of discrete flavor symmetry $G_f$ to different residual symmetries $G_{\\ell}$ and $G_\

  11. Soft See-Saw: Radiative Origin of Neutrino Masses in SUSY Theories

    CERN Document Server

    Megrelidze, Luka

    2016-01-01

    Radiative neutrino mass generation within supersymmetric (SUSY) construction is studied. The mechanism is considered where the lepton number violation is originating from the soft SUSY breaking terms. This requires extensions of the MSSM with states around the TeV scale. We present several explicit realizations based on extensions either by MSSM singlet or SU(2)_w triplet states. Besides some novelties of the proposed scenarios, various phenomenological implications are also discussed.

  12. Soft see-saw: Radiative origin of neutrino masses in SUSY theories

    Directory of Open Access Journals (Sweden)

    Luka Megrelidze

    2017-01-01

    Full Text Available Radiative neutrino mass generation within supersymmetric (SUSY construction is studied. The mechanism is considered where the lepton number violation is originating from the soft SUSY breaking terms. This requires MSSM extensions with states around the TeV scale. We present several explicit realizations based on extensions either by MSSM singlet or SU(2w triplet states. Besides some novelties of the proposed scenarios, various phenomenological implications are also discussed.

  13. Inverse neutrino mass hierarchy in a flavour GUT model

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Stefan, E-mail: stefan.antusch@unibas.ch [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 München (Germany); Gross, Christian, E-mail: christian.gross@unibas.ch [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland); Maurer, Vinzenz, E-mail: vinzenz.maurer@unibas.ch [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland); Sluka, Constantin, E-mail: constantin.sluka@unibas.ch [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland)

    2014-02-15

    We construct a supersymmetric SU(5)×A{sub 4} flavour GUT model in which an inverse neutrino mass hierarchy is realised without fine-tuning of parameters. The model shares some properties with the normal hierarchy model which we presented in (arXiv:1305.6612) – in particular the relation θ{sub 13}{sup PMNS}≃θ{sub C}/√(2). Besides these shared features, there are also important differences, mainly due to the different neutrino sector. These differences not only change the predictions in the lepton sector, but also in the quark sector, and will allow to discriminate between the two models using the results of present and future experiments. From a Markov Chain Monte Carlo fit we find that the inverse hierarchy model is in excellent agreement with the present experimental data.

  14. Inverse neutrino mass hierarchy in a flavour GUT model

    CERN Document Server

    Antusch, Stefan; Maurer, Vinzenz; Sluka, Constantin

    2014-01-01

    We construct a supersymmetric SU(5) x A_4 flavour GUT model in which an inverse neutrino mass hierarchy is realised without fine-tuning of parameters. The model shares some properties with the normal hierarchy model which we presented in arXiv:1305.6612 - in particular the relation theta_13^PMNS = theta_C / sqrt(2). Besides these shared features, there are also important differences, mainly due to the different neutrino sector. These differences not only change the predictions in the lepton sector, but also in the quark sector, and will allow to discriminate between the two models using the results of present and future experiments. From a Markov Chain Monte Carlo fit we find that the inverse hierarchy model is in excellent agreement with the present experimental data.

  15. Neutrino pair annihilation near accreting, stellar-mass black holes

    CERN Document Server

    Birkl, R; Janka, H T; Müller, E

    2006-01-01

    We investigate the energy-momentum deposition due to neutrino-antineutrino annihilation in the vicinity of axisymmetric, accreting black holes (BHs) by numerically ray-tracing neutrino trajectories in a Kerr space-time. Hyperaccreting stellar-mass BHs are widely considered as energy sources that can drive ultrarelativistic outflows with the potential to produce gamma-ray bursts. In contrast to earlier works, we provide an extensive and detailed parameter study of the influence of general relativistic (GR) effects and of different neutrinosphere geometries. These include idealized thin disks, tori, and spheres, or are constructed as non-selfgravitating equilibrium matter distributions for varied BH rotation. Considering isothermal neutrinospheres with the same temperature and surface area, we confirm previous results that compared to Newtonian calculations, GR effects increase the annihilation rate measured by an observer at infinity by a factor of 2 when the neutrinosphere is a disk. However, in case of a tor...

  16. Explaining the CMS excesses, baryogenesis, and neutrino masses in a E6 motivated U (1 )N model

    Science.gov (United States)

    Dhuria, Mansi; Hati, Chandan; Sarkar, Utpal

    2016-01-01

    We study the superstring inspired E6 model motivated U (1 )N extension of the supersymmetric standard model to explore the possibility of explaining the recent excess CMS events and the baryon asymmetry of the Universe in eight possible variants of the model. In light of the hints from short-baseline neutrino experiments at the existence of one or more light sterile neutrinos, we also study the neutrino mass matrices dictated by the field assignments and the discrete symmetries in these variants. We find that all the variants can explain the excess CMS events via the exotic slepton decay, while for a standard choice of the discrete symmetry four of the variants have the feature of allowing high scale baryogenesis (leptogenesis). For one other variant three body decay induced soft baryogenesis mechanism is possible which can induce baryon number violating neutron-antineutron oscillation. We also point out a new discrete symmetry which has the feature of ensuring proton stability and forbidding tree level flavor changing neutral current processes while allowing for the possibility of high scale leptogenesis for two of the variants. On the other hand, neutrino mass matrix of the U (1 )N model variants naturally accommodates three active and two sterile neutrinos which acquire masses through their mixing with extra neutral fermions giving rise to interesting textures for neutrino masses.

  17. Astrophysical implications of the neutrino rest mass. III. Nonlinear growth of perturbations and the missing mass

    Energy Technology Data Exchange (ETDEWEB)

    Doroshkevich, A.G.; Zel' dovich, Y.B.; Syunyaev, R.A.; Khlopov, M.Y.

    1980-07-01

    A discussion is given of the influence that a finite rest mass for the neutrino would have on the phenomenon of ''missing mass'' in galaxies and clusters of galaxies, on the nonlinear stage in the evolution of primordial irregularities, and on the problem of observing neutral hydrogen in the spectrum of distant quasars.

  18. Quasi-degenerate Neutrino mass models and their significance: A model independent investigation

    CERN Document Server

    Roy, S

    2016-01-01

    The prediction of possible ordering of neutrino masses relies mostly on the model selected. Alienating the $\\mu-\\tau$ interchange symmetry from discrete flavour symmetry based models, turns the neutrino mass matrix less predictive. But this inspires one to seek the answer from other phenomenological frameworks. We need a proper parametrization of the neutrino mass matrices concerning individual hierarchies. In the present work, we attempt to study the six different cases of Quasi-degenerate (QDN) neutrino models. The related mass matrices, $m_{LL}^{\

  19. Mass Hierarchy Determination Using Neutrinos from Multiple Reactors

    CERN Document Server

    Ciuffoli, Emilio; Zhang, Xinmin

    2012-01-01

    We report the results of Monte Carlo simulations of a medium baseline reactor neutrino experiment. The difference in baselines resulting from the 1 km separations of Daya Bay and Ling Ao reactors reduces the amplitudes of 1-3 oscillations at low energies, decreasing the sensitivity to the neutrino mass hierarchy. A perpendicular detector location eliminates this effect. We simulate experiments under several mountains perpendicular to the Daya Bay/Ling Ao reactors, considering in particular the background from the TaiShan and YangJiang reactor complexes. In general the hierarchy can be determined most reliably underneath the 1000 meter mountain BaiYunZhang, which is 44.5 km from Daya Bay. If some planned reactors are not built then nearby 700 meter mountains at 47-51 km baselines gain a small advantage. Neglecting their low overhead burdens, hills near DongKeng would be the optimal locations. We use a weighted Fourier transform to avoid a spurious dependence on the high energy neutrino spectrum and find that a...

  20. Neutrino oscillations: from an historical perspective to the present status

    Science.gov (United States)

    Bilenky, S.

    2016-05-01

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

  1. Neutrino oscillations: from an historical perspective to the present status

    CERN Document Server

    Bilenky, S

    2016-01-01

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

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

    Science.gov (United States)

    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.

  3. On the theory of neutrino mixing and oscillations

    CERN Document Server

    Bilenky, S M

    2010-01-01

    A brief review of the status of neutrino oscillations is given. The phenomenology of neutrino mixing and the standard seesaw mechanism of neutrino mass generation is discussed. Different approaches to neutrino oscillations are considered and compared. The role of the Heisenberg space-momentum uncertainty relation and the Mandelstam-Tamm time-energy uncertainty relation in neutrino oscillations is discussed in some detail.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bilenky, S., E-mail: bilenky@gmail.com [Joint Institute for Nuclear Research, Dubna, R-141980 (Russian Federation); TRIUMF 4004 Wesbrook Mall, Vancouver BC, V6T 2A3 Canada (Canada)

    2016-07-15

    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.

  5. Dark matter and neutrino masses from a classically scale-invariant multi-Higgs portal

    CERN Document Server

    Karam, Alexandros

    2016-01-01

    We present a classically scale-invariant model where the dark matter, neutrino and electroweak mass scales are dynamically generated from dimensionless couplings. The Standard Model gauge sector is extended by a dark $SU(2)_X$ gauge symmetry that is completely broken through a complex scalar doublet via the Coleman-Weinberg mechanism. The three resulting dark vector bosons of equal mass are stable and can play the role of dark matter. We also incorporate right-handed neutrinos which are coupled to a real singlet scalar that communicates with the other scalars through portal interactions. The multi-Higgs sector is analyzed by imposing theoretical and experimental constraints. We compute the dark matter relic abundance and study the possibility of the direct detection of the dark matter candidate from XENON 1T.

  6. Small Violation of Universal Yukawa Coupling and Neutrino Large Mixing

    CERN Document Server

    Teshima, T

    2001-01-01

    We assume the universal Yukawa coupling (democratic mass matrix) with small violations for quarks, charged leptons and neutrinos masses. We could reproduce the mass hierarchy for quark masses and V_{CKM} matrix elements precisely. We adopt the see-saw mechanism for the explanation of smallness of neutrino masses and introduce the right-handed Majorana neutrinos and Dirac neutrinos. We assume the universal Yukawa coupling with small violations for Majorana and Dirac neutrinos. We can get the hierarchy of charged lepton masses and effective neutrino masses and the large mixing of neutrinos expressed in V_{NMS}.

  7. Hints on the high-energy seesaw mechanism from the low-energy neutrino spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Casas, J.A.; Jimenez-Alburquerque, F. [Univ. Autonoma de Madrid (Spain). IFT-UAM/CSIC, C-XVI; Ibarra, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-12-15

    It is an experimental fact that the mass ratio for the two heavier neutrinos, h=m{sub 3}/m{sub 2}neutrino masses can be a consequence of the peculiar way they are generated through a see-saw mechanism, determining 1) How the present experimental data restrict the structure of the high-energy seesaw parameters and 2) Which choices, among the allowed ones, produce more naturally the observed pattern of neutrino masses. We have studied in particular if starting with hierarchical neutrino Yukawa couplings, as for the other fermions, one can naturally get the observed hmechanism in terms of (high-energy) basis-independent quantities. Among the main results, we find that in most cases m{sub 3}/m{sub 2} >> m{sub 3}/m{sub 2}, so m{sub 1} should be extremely tiny. Also, the V{sub R} matrix associated to the neutrino Yukawa couplings has a far from random structure, naturally resembling V{sub CKM}. In fact we show that identifying V{sub R} and V{sub CKM}, as well as neutrino and u-quark Yukawa couplings can reproduce h{sup exp} in a highly non-trivial way, which is very suggestive. The physical implications of these results are also discussed. (orig.)

  8. CP violation and neutrino masses and mixings from quark mass hierarchies

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Covi, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Emmanuel-Costa, D. [CFTP, Departamento de Fisica, Istituto Superior Tecnico, Lisbon (Portugal); Wiesenfeldt, S. [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Physics

    2007-10-15

    We study the connection between quark and lepton mass matrices in a supersymmetric SO(10) GUT model in six dimensions, compactified on an orbifold. The physical quarks and leptons are mixtures of brane and bulk states. This leads to a characteristic pattern of mass matrices and high-energy CP violating phases. The hierarchy of up and down quark masses determines the CKM matrix and most charged lepton and neutrino masses and mixings. The small hierarchy of neutrino masses is a consequence of the mismatch of the up and down quark mass hierarchies. The effective CP violating phases in the quark sector, neutrino oscillations and leptogenesis are unrelated. In the neutrino sector we can accomodate naturally sin {theta}{sub 23} {proportional_to}1, sin {theta}{sub 13}

  9. $\\mu\\to e\\gamma$ in a supersymmetric radiative neutrino mass model

    CERN Document Server

    Hundi, Raghavendra Srikanth

    2016-01-01

    We have considered a supersymmetric version of the inert Higgs doublet model, whose motivation is to explain smallness of neutrino masses and existence of dark matter. In this supersymmetric model, due to the presence of discrete symmetries, neutrinos acquire masses at loop level. After computing these neutrino masses, in order to fit the neutrino oscillation data, we have shown that by tuning some supersymmetry breaking soft parameters of the model, neutrino Yukawa couplings can be unsuppressed. In the above mentioned parameter space, we have computed branching ratio of the decay $\\mu\\to e\\gamma$. To be consistent with the current experimental upper bound on $Br(\\mu\\to e\\gamma)$, we have obtained constraints on the right-handed neutrino mass of this model.

  10. NEUTRINO MASS AND NEUTRINO OSCILLATION EXPERIMENTS%中微子质量和中微子振荡实验

    Institute of Scientific and Technical Information of China (English)

    何景棠

    2001-01-01

    The history and status of neutrino mass measurements are summarized in this paper. Several experimental results on solar neutrino missing and on atmospheric muon neutrino missing are described. These results imply that there are neutrino oscillations, this means that neutrino has mass. This is the signal of beyond the standard model. Several important experiments to study neutrino oscillation in the beginning of the 21st century, such as long-base-line neurino oscillation, the idea to build a muon storage ring for producing a high energy electron neutrino beam to carry out neutrino oscillation experiment and to measure the CP violation in neutrino oscillation, are also introduced.%本文介绍中微子质量测量的历史和现状。介绍太阳中微子丢失实验的结果和大气μ中微子丢失实验结果。这些结果表明存在中微子振荡,即中微子具有质量。它是超出标准模型的信号。本文还介绍了21世纪初研究中微子振荡的若干重要实验,例如长基线中微子振荡实验以及建造μ子贮存环来产生高能电子中微子束进行中微子振荡的实验以及测量中微子振荡时的CP破坏的设想。

  11. Models with radiative neutrino masses and viable dark matter candidates

    CERN Document Server

    Restrepo, Diego; Yaguna, Carlos

    2013-01-01

    We provide a list of particle physics models at the TeV-scale that are compatible with neutrino masses and dark matter. In these models, the Standard Model particle content is extended with a small number (\\leq 4) of scalar and fermion fields transforming as singlets, doublets or triplets under SU(2), and neutrino masses are generated radiatively via 1-loop diagrams. The dark matter candidates are stabilized by a Z_2 symmetry and are in general mixtures of the neutral components of such new multiplets. We describe the particle content of each of these models and determine the conditions under which they are consistent with current data. We find a total of 35 viable models, most of which have not been previously studied in the literature. There is a great potential to test these models at the LHC not only due to the TeV-scale masses of the new fields but also because about half of the viable models contain particles with exotic electric charges, which give rise to background-free signals. Our results should se...

  12. Three-Flavor Analysis of Neutrino Mixing with and without Mass Hierarchy

    CERN Document Server

    Minakata, H

    1996-01-01

    I summarize the results of barely model-dependent phenomenological analyses of the structure of the neutrino flavor mixing. The analyses are based on the three-flavor mixing framework without sterile neutrinos and utilize the hints from solar and atmospheric neutrino observations as well as that from mixed dark matter cosmology. It will be demonstrated that the features of the analysis is sharply distinguished by the two cases (I) with and (II) without dark matter mass scale, and by whether one (or two) mass is dominant (OMD) or the three states are almost degenerate (ADN). The global features of the neutrino mixing is illuminated for these different mass patterns.

  13. CP violating phase from minimal texture neutrino mass matrix: Test of the phase relevant to leptogenesis

    CERN Document Server

    Fukugita, Masataka; Shimizu, Yusuke; Tanimoto, Morimitsu; Yanagida, Tsutomu T

    2016-01-01

    The model of neutrino mass matrix with minimal texture is now tightly constrained by experiment so that it can yield a prediction for the phase of CP violation. This phase is predicted to lie in the range $\\delta_{CP}=0.77\\pi - 1.24\\pi$. If neutrino oscillation experiment would find the CP violation phase outside this range, this means that the minimal-texture neutrino mass matrix, the element of which is all real, fails and the neutrino mass matrix must be complex, i.e., the phase must be present that is responsible for leptogenesis.

  14. Generation of non-zero $\\theta_{13}$ in broken $A_4$ neutrino mass model

    CERN Document Server

    Borah, Manikanta; Das, Mrinal Kumar

    2014-01-01

    Stability of neutrino masses and mixings with non-zero $\\theta_{13}$ is an important issue in recent neutrino physics. In context of this, a detail analysis on two-fold degenerate $(m_1=m_2, m_3)$ neutrino mass model is done with Renormaization Group Equation (RGE) in Minimal Supersymmetric Standard Model (MSSM). Considering the input values of neutrino masses and mixing angles at high scale predictions are studied at low energy scale using RGE. We have also found that two-fold degenerate model with $\\theta_{13}=0$ can produce consistent results at low energy with non-zero $\\theta_{13}$ from the breaking of a generic $A_4$ model.

  15. The Microcalorimeter Arrays for a Rhenium Experiment (MARE): a next-generation calorimetric neutrino mass experiment

    CERN Document Server

    Monfardini, A; Brofferio, C; Capelli, S; Capozzi, F; Cremonesi, O; Enss, C; Fiorini, E; Fleischmann, A; Foggetta, L; Gallinaro, G; Gastaldo, L; Gatti, F; Giuliani, A; Gorla, P; Kelley, R; Kilbourne, C A; Margesin, B; McCammon, D; Nones, C; Nucciotti, A; Pavan, M; Pedretti, M; Pergolesi, D; Pessina, G; Porter, F S; Prest, M; Previtali, E; Repetto, P; Ribeiro-Gomez, M; Sangiorgio, S; Sisti, M

    2006-01-01

    Neutrino oscillation experiments have proved that neutrinos are massive particles, but can't determine their absolute mass scale. Therefore the neutrino mass is still an open question in elementary particle physics. An international collaboration is growing around the project of Microcalorimeter Arrays for a Rhenium Experiment (MARE) for directly measuring the neutrino mass with a sensitivity of about 0.2eV/c2. Many groups are joining their experiences and technical expertise in a common effort towards this challenging experiment. We discuss the different scenarios and the impact of MARE as a complement of KATRIN.

  16. Scotogenic $Z_2$ or $U(1)_D$ Model of Neutrino Mass with $\\Delta(27)$ Symmetry

    CERN Document Server

    Ma, Ernest

    2014-01-01

    The scotogenic model of radiative neutrino mass with $Z_2$ or $U(1)_D$ dark matter is shown to accommodate $\\Delta(27)$ symmetry naturally. The resulting neutrino mass matrix is identical to either of two forms, one proposed in 2006, the other in 2008. These two structures are studied in the context of present neutrino data, with predictions of $CP$ violation and neutrinoless double beta decay.

  17. Neutrino flavor oscillations in rotating matter

    CERN Document Server

    Dvornikov, Maxim

    2010-01-01

    We study the evolution of the neutrinos system in rotating matter. Neutrinos are supposed to be mixed massive particles interacting with background fermions by means of the electroweak forces. First we find the solutions of wave equations for the neutrino mass eigenstates in matter. Then we study the behavior of neutrino flavor eigenstates in background matter. The problems of neutrino bound states and neutrino flavor oscillations are discussed. We also derive the analog of the quantum mechanical evolution equation for the system of two flavor neutrinos in rotating matter and analyze its solution for the particular initial condition for neutrino flavor eigenstates.

  18. A Possible Quantum-Gravitational Origin of the Neutrino Mass Difference ?

    CERN Document Server

    Mavromatos, Nikolaos E; Mavromatos, Nick E.; Sarkar, Sarben

    2006-01-01

    We discuss the theoretical possibility that the neutrino mass differences have part of their origin in the quantum-decoherence-inducing medium of space-time foam, which characterises some models of quantum gravity, in much the same way as the celebrated MSW effect, responsible for the contribution to mass differences when neutrinos pass through ordinary material media. We briefly describe consequences of such decoherent media in inducing CPT violation at a fundamental level, which would affect the neutrino oscillation probability; we speculate on the connection of such phenomena with the role of neutrinos for providing one possible source of a cosmological constant in the Universe, of the phenomenologically right order of magnitude. Finally we discuss possible experimental constraints on the amount of neutrino mass differences induced by quantum gravity, which are based on fits of a simple decoherence model with all the currently available neutrino data.

  19. Shedding Light on Neutrino Masses with Dark Forces

    CERN Document Server

    Batell, Brian; Shuve, Brian

    2016-01-01

    Heavy right-handed neutrinos (RHNs) provide the simplest explanation for the origin of light neutrino masses and mixings. If the RHN masses are at or below the weak scale, direct experimental discovery of these states is possible at accelerator experiments such as the LHC or new dedicated beam dump experiments; in such experiments, the RHN decays after traversing a macroscopic distance from the collision point. The experimental sensitivity to RHNs is significantly enhanced if there is a new "dark" gauge force connecting them to the Standard Model (SM), and detection of RHNs can be the primary discovery mode for the new dark force itself. We take the well-motivated example of a B-L gauge symmetry and analyze the sensitivity to displaced decays of the RHNs produced via the new gauge interaction in two experiments: the LHC and the proposed SHiP beam dump experiment. In the most favorable case in which the mediator can be produced on-shell and decays to RHNs, the sensitivity reach is controlled by the square of t...

  20. Neutrino masses and mixings: Status of known and unknown $3\

    CERN Document Server

    Capozzi, F; Marrone, A; Montanino, D; Palazzo, A

    2016-01-01

    Within the standard 3nu mass-mixing framework, we present an up-to-date global analysis of neutrino oscillation data (as of January 2016), including the latest available results from experiments with atmospheric neutrinos (Super-Kamiokande and IceCube DeepCore), at accelerators (first T2K anti-nu and NOvA nu runs in both appearance and disappearance mode), and at short-baseline reactors (Daya Bay and RENO far/near spectral ratios), as well as a reanalysis of older KamLAND data in the light of the "bump" feature recently observed in reactor spectra. We discuss improved constraints on the five known oscillation parameters (delta m^2, |Delta m^2|, sin^2theta_12, sin^2theta_13, sin^2theta_23), and the status of the three remaining unknown parameters: the mass hierarchy, the theta_23 octant, and the possible CP-violating phase delta. With respect to previous global fits, we find that the reanalysis of KamLAND data induces a slight decrease of both delta m^2 and sin^2theta_12, while the latest accelerator and atmos...

  1. Very Low Energy Supernovae from Neutrino Mass Loss

    CERN Document Server

    Lovegrove, Elizabeth

    2013-01-01

    The continuing difficulty of achieving a reliable explosion in simulations of core-collapse supernovae, especially for more massive stars, has led to speculation concerning the observable transients that might be produced if such a supernova fails. Even if a prompt outgoing shock fails to form in a collapsing presupernova star, one must still consider the hydrodynamic response of the star to the abrupt loss of mass via neutrinos as the core forms a protoneutron star. Following a suggestion by Nadezhin (1980), we calculate the hydrodynamical responses of typical supernova progenitor stars to the rapid loss of approximately 0.2 to 0.5 M_sun of gravitational mass from their centers. In a red supergiant star, a very weak supernova with total kinetic energy ~ 10^47 erg results. The binding energy of a large fraction of the hydrogen envelope before the explosion is of the same order and, depending upon assumptions regarding the neutrino loss rates, most of it is ejected. Ejection speeds are ~ 100 km/s and luminosit...

  2. Neutrino Physics

    Science.gov (United States)

    Bergström, L.; Hulth, P. O.; Botner, O.; Carlson, P.; Ohlsson, T.

    2006-03-01

    J. N. Bahcall (1934-2005) -- Preface -- List of participants -- Committees -- Nobel symposium on neutrino physics - program -- The history of neutrino oscillations / S. M. Bilenky -- Super-Kamiokande results on neutrino oscillations / Y. Suzuki -- Sudbury neutrino observatory results / A. B. McDonald -- Results from KamLAND reactor neutrino detection / A. Suzuki -- New opportunities for surprise / J. Conrad -- Solar models and solar neutrinos / J. N. Bahcall -- Atmospheric neutrino fluxes / T. K. Gaisser -- The MSW effect and matter effects in neutrino oscillations / A. Yu. Smirnov -- Three-flavour effects and CP- and T-violation in neutrino oscillations / E. Kh. Akhmedov -- Global analysis of neutrino data / M. C. Gonzalez-Garcia -- Future precision neutrino oscillation experiments and theoretical implications / M. Lindner -- Experimental prospects of neutrinoless double beta decay / E. Fiorini -- Theoretical prospects of neutrinoless double beta decay / S. T. Petcov -- Supernova neutrino oscillations / G. G. Raffelt -- High-energy neutrino astronomy / F. Halzen -- Neutrino astrophysics in the cold: Amanda, Baikal and IceCube / C. Spiering -- Status of radio and acoustic detection of ultra-high energy cosmic neutrinos and a proposal on reporting results / D. Saltzberg -- Detection of neutrino-induced air showers / A. A. Watson -- Prospect for relic neutrino searches / G. B. Gelmini -- Leptogenesis in the early universe / T. Yanagida -- Neutrinos and big bang nucleosynthesis / G. Steigman -- Extra galactic sources of high energy neutrinos / E. Waxman -- Cosmological neutrino bounds for non-cosmologists / M. Tegmark -- Neutrino intrinsic properties: the neutrino-antineutrino relation / B. Kayser -- NuTeV and neutrino properties / M. H. Shaevitz -- Absolute masses of neutrinos - experimental results and future possibilities / C. Weinheimer -- Flavor theories and neutrino masses / P. Ramond -- Neutrino mass models and leptogenesis / S. F. King -- Neutrino mass and

  3. Baryon Triality And Neutrino Masses From An Anomalous FlavorU(1)

    Energy Technology Data Exchange (ETDEWEB)

    Dreiner, Herbi K.; Luhn, Christoph; Murayama, Hitoshi; Thormeier,Marc

    2007-08-15

    We construct a concise U(1){sub X} Froggatt-Nielsen model in which baryon triality, a discrete gauge Z{sub 3}-symmetry, arises from U(1){sub X} breaking. The proton is thus stable, however, R-parity is violated. With the proper choice of U(1){sub X} charges we can obtain neutrino masses and mixings consistent with an explanation of the atmospheric and solar neutrino anomalies in terms of neutrino oscillations, with no right-handed neutrinos required. The only mass scale apart from M{sub grav} is m{sub soft}.

  4. Near maximal atmospheric mixing in neutrino mass matrices with two vanishing minors

    Energy Technology Data Exchange (ETDEWEB)

    Dev, S., E-mail: dev5703@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Gupta, Shivani, E-mail: shiroberts_1980@yahoo.co.in [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Gautam, Radha Raman, E-mail: gautamrrg@gmail.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Singh, Lal, E-mail: lalsingh96@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

    2011-12-06

    In the flavor basis there are seven cases of two vanishing minors in the neutrino mass matrix which can accommodate the present neutrino oscillation data including the recent T2K data. It is found that two of these cases, namely B{sub 5} and B{sub 6} predict near maximal atmospheric neutrino mixing in the limit of large effective neutrino mass. This feature remains irrespective of the values of solar and reactor mixing angles. A non-zero reactor mixing angle is naturally accommodated in these textures.

  5. Search for heavy lepton partners of neutrinos in the context of type-III Seesaw Mechanism at CMS

    CERN Document Server

    AUTHOR|(CDS)2091444

    2015-01-01

    The Seesaw Mechanism was introduced to explain why the masses of neutrinos are many orders of magnitude smaller than the other lepton masses. Considering neutrinos as Majorana particles, ``natural'' Yukawa couplings yield neutrinos with very small masses, along with heavy partners. Such particles may be observable at the LHC experiments. CMS searched for a fermionic triplet (type-III Seesaw Mechanism) by selecting events with three isolated leptons, jets and missing transverse energy in the final state. Backgrounds are due to events with leptons from electroweak processes either leptons coming from secondary vertices or ``fake leptons''. The estimate of fake leptons is a crucial point of the analysis. Results obtained with data collected in 2012, corresponding to 19.7~$\\mbox{fb}^{-1}$ and $\\sqrt{s}$= 8 TeV, show no evidence of signal, and so we have set lower limits on the masses of the fermionic triplet.

  6. Bursts of gravitational radiation from superconducting cosmic strings and the neutrino mass spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias; Morejon Gonzalez, Danays [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

    2001-02-01

    Berezinsky, Hnatyk and Vilenkin showed that superconducting cosmic strings could be central engines for cosmological gamma-ray bursts and for producing the neutrino component of ultra-high energy cosmic rays. A consequence of this mechanism would be that a detectable cusp-triggered gravitational wave burst should be release simultaneously with the {gamma}-ray surge. If contemporary measurements of both {gamma} and {nu} radiation could be made for any particular source, then the cosmological time-delay between them might be useful for putting unprecedently tight bounds on the neutrino mass spectrum. Such measurements could consistently verify or rule out the model since strictly correlated behaviour is expected for the duration of the event and for the time variability of the spectra. (author)

  7. More is different: Reconciling eV sterile neutrinos with cosmological mass bounds

    Directory of Open Access Journals (Sweden)

    Yong Tang

    2015-11-01

    Full Text Available It is generally expected that adding light sterile species would increase the effective number of neutrinos, Neff. In this paper we discuss a scenario that Neff can actually decrease due to the neutrino oscillation effect if sterile neutrinos have self-interactions. We specifically focus on the eV mass range, as suggested by the neutrino anomalies. With large self-interactions, sterile neutrinos are not fully thermalized in the early Universe because of the suppressed effective mixing angle or matter effect. As the Universe cools down, flavor equilibrium between active and sterile species can be reached after big bang nucleosynthesis (BBN epoch, but leading to a decrease of Neff. In such a scenario, we also show that the conflict with cosmological mass bounds on the additional sterile neutrinos can be relaxed further when more light species are introduced. To be consistent with the latest Planck results, at least 3 sterile species are needed.

  8. More Is Different: Reconciling eV Sterile Neutrinos and Cosmological Mass Bounds

    CERN Document Server

    Tang, Yong

    2015-01-01

    It is generally expected that adding light sterile species would increase the effective number of neutrinos, $N_{\\textrm{eff}}$. In this paper we discuss a scenario that $N_{\\textrm{eff}}$ can actually decrease due to the neutrino oscillation effect if sterile neutrinos have self-interactions. We specifically focus on the eV mass range, as suggested by the neutrino anomalies. With large self-interactions, sterile neutrinos are not fully thermalized in the early Universe because of the suppressed effective mixing angle or matter effect. As the Universe cools down, flavor equilibrium between active and sterile species can be reached after big bang nucleosynthesis (BBN) epoch, but leading to a decrease of $N_{\\textrm{eff}}$. In such a scenario, we also show that the conflict with cosmological mass bounds on the additional sterile neutrinos can be relaxed further when more light species are introduced.

  9. Physics of Neutrino Oscillation

    CERN Document Server

    Mondal, Spandan

    2015-01-01

    The Standard Model of particle physics describes neutrinos as massless, chargeless elementary particles that come in three different flavours. However, recent experiments indicate that neutrinos not only have mass, but also have multiple mass eigenstates that are not identical to the flavour states, thereby indicating mixing. As an evidence of mixing, neutrinos have been observed to change from one flavour to another during their propagation, a phenomenon called neutrino oscillation. We have studied the reasons and derived the probabilities of neutrino flavour change, both in vacuum and in matter. We have also studied the parameters affecting this probability. We have discussed the special case of two-neutrino oscillations. Lastly, we have discussed some basic properties of neutrinos that are reflected in the previous derivations and highlighted a few relevant open problems. To begin with, we have also studied the relevant topics in introductory High Energy Physics and Quantum Mechanics to familiarize with th...

  10. Neutrinos, a window on new physics

    CERN Document Server

    van Holten, J W

    2014-01-01

    This paper reviews some aspects of the physics of neutrinos, in particular neutrino masses and the issue of Dirac versus Majorana neutrinos. The see-saw mechanism is described and it is argued that the Majorana nature of neutrinos can be tested by measuring the invisible decays of the Higgs particle, as its decay into neutrinos is determined by their Yukawa couplings, i.e. the Dirac masses, rather than the physical Majorana masses. The measurement would allow us to probe the scale M of the large Majorana masses for right-handed singlet neutrinos. The optimal machine for performing such a measurement would be a future electron-positron collider.

  11. Two-loop snail diagrams: relating neutrino masses to dark matter

    CERN Document Server

    Farzan, Yasaman

    2014-01-01

    Various mechanisms have been developed to explain the origin of Majorana neutrino masses. One of them is radiative mass generation. Two-loop mass generation is of particular interest because the masses and couplings of new particles propagating in the loop can be in the range testable by other experiments and observations. In order for the radiative mass suppression to be reliable, it should be guaranteed that lower loop contributions are suppressed. Based on loop topology and the form of electroweak presentation of the particles propagating in the loop, one can determine whether a lower---and therefore dominant---loop contribution is possible. We present a model based on these general considerations which leads to neutrino masses via a two-loop diagram which we dub as "snail-diagram". The model has two natural candidates for dark matter one of them being a neutral Dirac fermion which can satisfy the conditions of the thermal freeze-out scenario by annihilation to lepton pairs. We comment on the possibility o...

  12. Two-loop snail diagrams: relating neutrino masses to dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Farzan, Yasaman [Physics school, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2015-05-06

    Various mechanisms have been developed to explain the origin of neutrino masses. One of them is radiative mass generation. Two-loop mass generation is of particular interest because the masses and couplings of new particles propagating in the loop can be in the range testable by other experiments and observations. In order for the radiative mass suppression to be reliable, it should be guaranteed that lower loop contributions are suppressed. Based on loop topology and the form of electroweak presentation of the particles propagating in the loop, one can determine whether a lower — and therefore dominant — loop contribution is possible. We present a model based on these general considerations which leads to neutrino masses via a two-loop diagram which we dub as “snail-diagram”. The model has two natural candidates for dark matter one of them being a neutral Dirac fermion which can satisfy the conditions of the thermal freeze-out scenario by annihilation to lepton pairs. We comment on the possibility of explaining the GeV gamma ray excess observed by Fermi-LAT from the region close to the Galaxy Center. We also discuss possible signals at the LHC and at experiments searching for lepton flavor violating rare decays.

  13. Strong thermal leptogenesis and the absolute neutrino mass scale

    CERN Document Server

    Di Bari, Pasquale; Fiorentin, Michele Re

    2014-01-01

    We show that successful strong thermal leptogenesis, where the final asymmetry is independent of the initial conditions and in particular a large pre-existing asymmetry is efficiently washed-out, favours values of the lightest neutrino mass $m_1 \\gtrsim 10\\,{\\rm meV}$ for normal ordering (NO) and $m_1 \\gtrsim 3\\,{\\rm meV}$ for inverted ordering (IO). We show analytically why lower values of $m_1$ require a high level of fine tuning in the seesaw formula and/or in the flavoured decay parameters (in the electronic for NO, in the muonic for IO). We also show how this constraint exists thanks to the measured values of the neutrino mixing angles and can be tighten by a future determination of the Dirac phase. Our analysis also allows to place more stringent constraint for a specific model or class of models, such as $SO(10)$-inspired models, and shows that some models cannot realise strong thermal leptogenesis for any value of $m_1$. A scatter plot analysis fully supports the analytical results. We also briefly di...

  14. Probing Radiative Neutrino Mass Generation through Monotop Production

    CERN Document Server

    Ng, John N

    2014-01-01

    We present a generalization of a model where the right-handed up-type quarks serve as messengers for neutrino mass generation and as a portal for dark matter. Within this framework the Standard Model is extended with a single Majorana neutrino, a coloured electroweak-singlet scalar and a coloured electroweak-triplet scalar. We calculate the relic abundance of dark matter and show that we can match the latest experimental results. Furthermore, the implications from the scattering between nuclei and the dark matter candidate are studied and we implement the latest experimental constraints arising from flavour changing interactions, Higgs production and decay and LHC collider searches for a single jet and jets plus missing energy. In addition, we implement constraints arising from scalar top quark pair-production. We also study the production of a single top in association with missing energy and calculate the sensitivity of the LHC to the top quark hadronic and semi-leptonic decay modes with the current $20$ fb...

  15. Probing neutrino mass with displaced vertices at the Tevatron

    CERN Document Server

    De Campos, F; Magro, M B; Porod, Werner; Restrepo, D; Valle, J W F

    2005-01-01

    Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well mixings. One interesting feature of these scenarios is that the lightest supersymmetric particle (LSP) is unstable, with several of its decay properties predicted in terms of neutrino mixing angles. A smoking gun of this model in colliders is the presence of displaced vertices due to LSP decays in large parts of the parameter space. In this work we focus on the simplest model of this type that comes from minimal supergravity with universal R-parity conserving soft breaking of supersymmetry (RmSUGRA). We evaluate the potentiality of the Fermilab Tevatron to probe the RmSUGRA parameters through the analysis of events possessing two displaced vertices stemming from LSP decays. We show that requiring two displaced vertices in the events leads to a reach in m_{1/2} twice the one in the usual multilepton signals in a large fraction of the parameter space.

  16. The (Z_2)^3 symmetry of the non-tri-bimaximal pattern for the neutrino mass matrix

    CERN Document Server

    Lashin, E I; Chamoun, N; Nasri, S

    2012-01-01

    In view of the recent neutrino oscillation data pointing to a non-vanishing value for the smallest mixing angle ($\\theta_z$), we derive and find explicit realizations of the $(Z_2)^3$ flavor symmetry which characterizes, for the neutrino mass matrix, uniquely a variant of the tripartite form, originally conceived to lead to the tri-bimaximal mixing with $\\theta_z=0$, so that to allow now for a non-tri-bimaximal pattern with non-zero $\\theta_z$. We impose this flavor symmetry in a setting including the charged leptons and we see that it can make room, through higher order terms involving new SM-singlet scalars, for the mass hierarchy of charged leptons. Moreover, within type-I seesaw mechanism augmented with the flavor symmetry, certain patterns occurring in both the Dirac and the Majorana neutrino mass matrices can accommodate all types of mass hierarchies in the effective neutrino mass matrix, but no lepton/baryon asymmetry can be generated. Finally, we discuss how type-II seesaw mechanism, when supplemented...

  17. Mean square number fluctuation for a fermion source and its dependence on neutrino mass for the universal cosmic neutrino background

    Indian Academy of Sciences (India)

    Swapnil S Jawkar; Sudhanshu S Jha

    2005-01-01

    Using the general formulation for obtaining chemical potential of an ideal Fermi gas of particles at temperature , with particle rest mass $m_{0}$ and average density $\\langle N \\rangle/V$ , the dependence of the mean square number fluctuation $\\langle N^{2} \\rangle/V$ on the particle mass $m_{0}$ has been calculated explicitly. The numerical calculations are exact in all cases whether rest mass energy $m_{0}c^{2}$ is very large (non-relativistic case), very small (ultrarelativistic case) or of the same order as the thermal energy $k_{B}T$ . Application of our results to the detection of the universal very low energy cosmic neutrino background (CNB), from any of the three species of neutrinos, shows that it is possible to estimate the neutrino mass of these species if from approximate experimental measurements of their momentum distribution one can extract, someday, not only the density $\\langle N_{} \\rangle/V$ but also the mean square fluctuation $\\langle N_{}^{2} \\rangle/V$. If at the present epoch, the universe is expanding much faster than thermalization rate for CNB, it is shown that our analysis leads to a scaled neutrino mass $m_{}$ instead of the actual mass $m_{0}.

  18. Determination of the neutrino mass hierarchy with a new statistical method

    CERN Document Server

    Stanco, L; Tenti, M

    2016-01-01

    Neutrino physics is nowadays undergoing a change of perspectives, the discovery period is almost over and we are entering the phase of precise measurements. Despite the limited statistics collected for some variables, the three--flavour neutrino framework seems well consolidating. In this framework a new method has been developed to determine the neutrino mass ordering, one of the still unknown and most relevant parameters. The method is applied to the 2015 results of the NOvA experiment for $\

  19. Large \\theta_13 from finite quantum corrections in quasi-degenerate neutrino mass spectrum

    CERN Document Server

    Araki, Takeshi

    2011-01-01

    We study finite quantum corrections for several well known neutrino mixing matrices and find that it is hard to account for the large value of \\theta_13 recently reported by T2K and MINOS. To nicely reproduce all experimentally favored neutrino mixing angles and masses, we propose a new neutrino mixing pattern. We also demonstrate a simple realization by slightly extending the standard model to illustrate the quantum corrections.

  20. Cosmic Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris; /Fermilab /CERN

    2008-02-01

    I recall the place of neutrinos in the electroweak theory and summarize what we know about neutrino mass and flavor change. I next review the essential characteristics expected for relic neutrinos and survey what we can say about the neutrino contribution to the dark matter of the Universe. Then I discuss the standard-model interactions of ultrahigh-energy neutrinos, paying attention to the consequences of neutrino oscillations, and illustrate a few topics of interest to neutrino observatories. I conclude with short comments on the remote possibility of detecting relic neutrinos through annihilations of ultrahigh-energy neutrinos at the Z resonance.

  1. Neutrino Oscillation, Finite Self-Mass and General Yang-Mills Symmetry

    CERN Document Server

    Hsu, Jong-Ping

    2016-01-01

    The conservation of lepton number is assumed to be associated with a general Yang-Mills symmetry. New transformations involve (Lorentz) vector gauge functions and characteristic phase functions, and they form a group. General Yang-Mills fields are associated with new fourth-order equations and linear potentials. Lepton self-masses turn out to be finite and proportional to the inverse of lepton masses, which implies that neutrinos should have non-zero masses. Thus, general Yang-Mills symmetry could provide an understanding of neutrino oscillations and suggests that neutrinos with masses and very weak leptonic force may play a role in dark matter.

  2. Correction to Neutrino Mass Square Difference in the Co-Bimaximal Mixings due to Quantum Gravity

    Science.gov (United States)

    Koranga, Bipin Singh; Narayan, Mohan

    2017-08-01

    We consider non-renormalizable interaction term as a perturbation of the neutrino mass matrix. We assume that the neutrino masses and mixing arise through physics at a scale intermediate between Planck scale and the electroweak breaking scale. We also assume that, just above the electroweak breaking scale, neutrino masses are nearly degenerate and their mixing is Co-bimaximal mixing by assumming mixing angle θ _{13}≠ 0=10°,θ _{23}=π/4, tanθ _{12}2= {1-3sinθ _{13}2}/{2}=34° and Dirac phase δ =± π/2. Quantum gravity (Planck scale effects) lead to an effective S U(2) L × U(1) invariant dimension-5 Lagrangian involving neutrino and Higgs fields. On symmetry breaking, this operator gives rise to correction to the above masses and mixing. The gravitational interaction M X = M p l , we find that for degenerate neutrino mass spectrum, the considered perturbation term change the {Δ }_{21}^' } by 12% and {Δ }_{31}^' } mass square difference is unchanged above GUT scale. The nature of gravitational interaction demands that the element of this perturbation matrix should be independent of flavor indices. In this paper, we study the quantum gravity effects on neutrino mass square difference, namely modified dispersion relation for neutrino mass square differences.

  3. Neutrino Physics

    CERN Document Server

    Gil-Botella, I

    2013-01-01

    The fundamental properties of neutrinos are reviewed in these lectures. The first part is focused on the basic characteristics of neutrinos in the Standard Model and how neutrinos are detected. Neutrino masses and oscillations are introduced and a summary of the most important experimental results on neutrino oscillations to date is provided. Then, present and future experimental proposals are discussed, including new precision reactor and accelerator experiments. Finally, different approaches for measuring the neutrino mass and the nature (Majorana or Dirac) of neutrinos are reviewed. The detection of neutrinos from supernovae explosions and the information that this measurement can provide are also summarized at the end.

  4. Neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Botella, I. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)

    2011-07-01

    The fundamental properties of neutrinos are reviewed in these lectures. The first part is focused on the basic characteristics of neutrinos in the Standard Model and how neutrinos are detected. Neutrino masses and oscillations are introduced and a summary of the most important experimental results on neutrino oscillations to date is provided. Then, present and future experimental proposals are discussed, including new precision reactor and accelerator experiments. Finally, different approaches for measuring the neutrino mass and the nature (Majorana or Dirac), of neutrinos are reviewed. The detection of neutrinos from supernovae explosions and the information that this measurement can provide are also summarized at the end. (author)

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

    CERN Document Server

    Sierra, D Aristizabal; Wegman, D

    2016-01-01

    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 $\\alpha_2$ reaches a Landau pole at rather low scales, typically comparable to 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 perturb...

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

    CERN Document Server

    Lu, Wen-Bin

    2016-01-01

    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 Z_2 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.

  7. A_4-based neutrino masses with Majoron decaying dark matter

    CERN Document Server

    Esteves, J N; Joshipura, A S; Romao, J C; Tortola, M A; Valle, J W F

    2010-01-01

    We propose an A_4 flavor-symmetric SU(3)xSU(2)xU(1) seesaw model where lepton number is broken spontaneously. A consistent two-zero texture pattern of neutrino masses and mixing emerges from the interplay of type-I and type-II seesaw contributions, with important phenomenological predictions. We show that, if the Majoron becomes massive, such seesaw scenario provides a viable candidate for decaying dark matter, consistent with cosmic microwave background lifetime constraints that follow from current WMAP observations. We also calculate the sub-leading one-loop-induced decay into photons which leads to a mono-energetic emission line that may be observed in future X-ray missions such as Xenia.

  8. Neutrino Mass Constraints on R violation and HERA anomaly

    CERN Document Server

    Joshipura, A S; Vempati, S K; Joshipura, Anjan S.; Vempati, Sudhir K.

    1999-01-01

    R parity violating trilinear couplings $\\lambda'_{1jk}$ of the minimal supersymmetric standard model (MSSM) are constrained from the limit on the electron neutrino mass. Strong limits on these couplings follow from the earlier neglected contribution due to sneutrino vacuum expectation values. The limits on most of the $\\lambda'_{1jk}$ couplings derived here are stronger than the existing limits for a wide range in parameters of MSSM. These limits strongly constrain the interpretation of recent HERA results in $e^+ p$ scattering in terms of production of squarks through $R$ violation couplings. In particular, the interpretation in terms of $\\tilde{t}_L$ production off strange quark as suggested recently is not viable for wide ranges in MSSM parameters.

  9. Spin-flavor oscillations of Dirac neutrinos described by relativistic quantum mechanics

    CERN Document Server

    Dvornikov, Maxim

    2010-01-01

    We study spin-flavor oscillations of Dirac neutrinos in matter and magnetic field using the method of relativistic quantum mechanics. We start from the exact solution of the wave equation for a massive neutrino, taking into account external fields. Then we derive an effective Hamiltonian governing neutrino spin-flavor oscillations. We demonstrate the consistency of our approach with the commonly used quantum mechanical method. Our correction to the usual effective Hamiltonian results in the appearance of a new resonance in neutrino oscillations. We discuss applications to spin-flavor neutrino oscillations in the expanding envelope of a supernova. In particular, transitions between right-handed electron neutrinos and sterile neutrinos are studied for a realistic background matter and magnetic field distributions. We also analyze the influence of other factors such as a longitudinal magnetic field, matter polarization, and the non-standard contributions to the neutrino effective potential.

  10. Dark Matter and Strong Electroweak Phase Transition in a Radiative Neutrino Mass Model

    CERN Document Server

    Ahriche, Amine

    2013-01-01

    We consider an extension of the standard model (SM) with charged singlet scalars and right handed (RH) neutrinos all at the electroweak scale. In this model, the neutrino masses are generated at three loops, which provide an explanation for their smallness, and the lightest RH neutrino, $N_{1}$, is a dark matter candidate. We find that for three generations of RH neutrinos, the model can be consistent with the neutrino oscillation data, lepton flavor violating processes, $N_{1}$ can have a relic density in agreement with the recent Planck data, and the electroweak phase transition can be strongly first order. We also show that the charged scalars may enhance the branching ratio $h-->YY$, where as $h-->YZ$ get can get few percent suppression. We also discuss the phenomenological implications of the RH neutrinos at the collider.

  11. How neutrinos get mass and what other things may happen besides oscillations?

    Indian Academy of Sciences (India)

    M A Ernest

    2000-07-01

    In this talk I address the theoretical issue of why new physics is required to obtain a nonzero neutrino mass. I then discuss what other things may happen besides neutrino oscillations. In particular I consider a possible new scenario of leptogenesis in -parity nonconserving supersymmetry.

  12. Comment on "The GSI method for studying neutrino mass differences - For Pedestrians"

    OpenAIRE

    Peshkin, Murray

    2008-01-01

    It has been suggested that the reported temporal oscillations in the weak decay of H-like ions circulating in the GSI storage ring may be accounted for by interference between two different momentum components of the wave function of the parent ions. In that model, the interference is said to come about through coupling of those two momentum components to the two mass components in the wave function of the electron neutrino in the decayed state. I show here that quantum mechanics allows no su...

  13. Quantum corrections to the effective neutrino mass operator in 5D MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Deandrea, Aldo; Welzel, Julien [Universite de Lyon 1, Institut de Physique Nucleaire, 4 rue E. Fermi, 69622 Villeurbanne Cedex (France); Hosteins, Pierre [SPhT, CEA-Saclay, 91191 Gif-sur-Yvette cedex (France); Oertel, Micaela [LUTH, Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon (France)

    2007-04-15

    We discuss in detail a five-dimensional Minimal Supersymmetric Standard Model compactified on S{sup 1}/Z{sub 2} extended by the effective Majorana neutrino mass operator. We study the evolution of neutrino masses and mixings. Masses and angles, in particular the atmospheric mixing angle {theta}{sub 23}, can be significantly lowered at high energies with respect to their value at low energy. (authors)

  14. Explaining the CMS excesses, baryogenesis and neutrino masses in $E_{6}$ motivated $U(1)_{N}$ model

    CERN Document Server

    Dhuria, Mansi; Sarkar, Utpal

    2016-01-01

    We study the superstring inspired $E_{6}$ model motivated $U(1)_{N}$ extension of the supersymmetric standard model to explore the possibility of explaining the recent excess CMS events and the baryon asymmetry of the universe in eight possible variants of the model. In light of the hints from short-baseline neutrino experiments at the existence of one or more light sterile neutrinos, we also study the neutrino mass matrices dictated by the field assignments and the discrete symmetries in these variants. We find that all the variants can explain the excess CMS events via the exotic slepton decay, while for a standard choice of the discrete symmetry four of the variants have the feature of allowing high scale baryogenesis (leptogenesis). For one other variant three body decay induced soft baryogenesis mechanism is possible which can induce baryon number violating neutron-antineutron oscillation. We also point out a new discrete symmetry which has the feature of ensuring proton stability and forbidding tree lev...

  15. TRIMS: Validating T2 Molecular Effects for Neutrino Mass Experiments

    Science.gov (United States)

    Lin, Ying-Ting; Bodine, Laura; Enomoto, Sanshiro; Kallander, Matthew; Machado, Eric; Parno, Diana; Robertson, Hamish; Trims Collaboration

    2017-01-01

    The upcoming KATRIN and Project 8 experiments will measure the model-independent effective neutrino mass through the kinematics near the endpoint of tritium beta-decay. A critical systematic, however, is the understanding of the molecular final-state distribution populated by tritium decay. In fact, the current theory incorporated in the KATRIN analysis framework predicts an observable that disagrees with an experimental result from the 1950s. The Tritium Recoil-Ion Mass Spectrometer (TRIMS) experiment will reexamine branching ratio of the molecular tritium (T2) beta decay to the bound state (3HeT+). TRIMS consists of a magnet-guided time-of-flight mass spectrometer with a detector located on each end. By measuring the kinetic energy and time-of-flight difference of the ions and beta particles reaching the detectors, we will be able to distinguish molecular ions from atomic ones and hence derive the ratio in question.We will give an update on simulation software, analysis tools, and the apparatus, including early commissioning results. U.S. Department of Energy Office of Science, Office of Nuclear Physics, Award Number DE-FG02-97ER41020.

  16. See-Saw scale discrete dark matter and two-zero texture Majorana neutrino mass matrices

    CERN Document Server

    Lamprea, J M

    2016-01-01

    In this paper we present a scenario where the stability of dark matter and the phenomenology of neutrinos are related by the spontaneous breaking of a non-Abelian flavor symmetry. In this scenario the breaking is done at the seesaw scale, in such a way that what remains of the flavor symmetry is a Z2 symmetry, which stabilizes the dark matter. We have proposed two models based on this idea, for which we have calculated their neutrino mass matrices achieving two-zero texture in both cases. Accordingly, we have updated this two-zero texture phenomenology finding an interesting correlation between the reactor mixing angle and the sum of the light neutrino masses. We also have a correlation between the lightest neutrino mass and the neutrinoless double beta decay effective mass, obtaining a lower bound for the effective mass within the region of the nearly future experimental sensitivities.

  17. LSP Squark Decays at the LHC and the Neutrino Mass Hierarchy

    CERN Document Server

    Marshall, Zachary; Purves, Austin; Spinner, Sogee

    2014-01-01

    The existence of R-parity in supersymmetric models can be naturally explained as being a discrete subgroup of gauged baryon minus lepton number (B-L). The most minimal supersymmetric B-L model triggers spontaneous R-parity violation, while remaining consistent with proton stability. This model is well-motivated by string theory and makes several interesting, testable predictions. Furthermore, R-parity violation contributes to neutrino masses, thereby connecting the neutrino sector to the decay of the lightest supersymmetric particle (LSP). This paper analyzes the decays of third generation squark LSPs into a quark and a lepton. In certain cases, the branching ratios into charged leptons reveal information about the neutrino mass hierarchy, a current goal of experimental neutrino physics, as well as the $\\theta_{23}$ neutrino mixing angle. Furthermore, optimization of leptoquark searches for this scenario is discussed. Using currently available data, the lower bounds on the third generation squarks are compute...

  18. An Axial Vector Nature of a Neutrino with an Electroweak Mass

    CERN Document Server

    Sharafiddinov, Rasulkhozha S

    2011-01-01

    A classification of elementary particles with respect to C-operation admits the existence of truly neutral types of fermions. Among them one can find both a Dirac and a Majorana neutrinos of an electroweak nature. Their mass includes the electric and weak parts, in the presence of which a neutrino has the anapole charge, charge radius and electric dipole moment. They constitute the paraneutrino of true neutrality, for example, at the neutrino interaction with a spinless nucleus of an axial-vector current. We derive the united equations which relate the structural components of mass to anapole, charge radius and electric dipole of each truly neutral neutrino at the level of flavour symmetry. Such a principle can explain the C-noninvariant nature of neutrinos and fields in the framework of constancy law of the size implied from the multiplication of a weak mass of the C-odd neutrino by its electric mass. From this point of view, all neutrinos of C-antisymmetricality regardless of the difference in masses of an ...

  19. Study of the mass of the electron neutrino in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, Shinjiro; Maezawa, Hideki [eds.

    1996-02-01

    This report describes a study of the mass of the electron neutrino using electron capture in {sup 163}Ho in Japan for the period from 1981 to 1994. This monograph has two purposes, one is to supplement the papers on the mass of the electron neutrino already published by us and another is to make a record on some details of our experiments for future. Electron capture in a nucleus takes place in a rather small space inside an atom, where atomic physics, nuclear physics and particle physics work closely together. Therefore, this study needed an intimate collaboration of atomic physicists, nuclear physicists and particle physicists. In addition, it was necessary for this study to use various fine techniques, including metallurgy, production of {sup 163}Ho activity, micro-analysis by wet chemistry, isotope-dilution mass spectrometry, undulator radiation source technology, the soft X-ray monochromator technology, a counting technique for very intense soft X-rays and so on. As a result, our collaboration consisted of many researchers from various fields as follows; M. Ando, H. Arai, M. Fujioka, N. Hashimoto, H. Ikeda, Y. Inagaki, K. Ishii, K. Itoh, G. Izawa, O. Kawakami, S. Kishimoto, H. Kitamura, H. Maezawa, M. Maruyama, A. Masuda, K. Masumoto, A. Mikuni, T. Mizogawa, T. Mukoyama, F. Ochiai, T. Ohta, T. Omori, G. Rajasekaran, K. Sera, K. Shima, T. Shinozuka, P.M. Stefan, I. Sugai, H. Taketani, M. Yagi, and S. Yasumi. Without such an excellent collaboration, this study would not have been completed. We would like to express our sincere gratitude to Professor T. Sasaki for supporting this study and recommending the undulator beam line of 2.5 GeV Photon Factory Storage Ring as a light source to be used in the experiment. We also would like to thank Dr. A. Yagishita and Dr. Y. Kitajima who are responsible for the BL-2 beamline. Finally we are grateful to Ms. M. Noji for her patient typewriting of manuscripts written by hand. (author).

  20. Anomalous Majorana Neutrino Masses from Torsionful Quantum Gravity

    CERN Document Server

    Mavromatos, Nick E

    2012-01-01

    The effect of quantum torsion in theories of quantum gravity is usually described by an axion-like field which couples to matter and to gravitation and radiation gauge fields. In perturbation theory, the couplings of this torsion-descent axion field are of derivative type and so preserve a shift symmetry. This shift symmetry may be broken, if the torsion-descent axion field mixes with other axions, which could be related to moduli fields in string-inspired effective theories. In particular, the shift symmetry may break explicitly via non-perturbative effects, when these axions couple to fermions via chirality changing Yukawa couplings with appropriately suppressed coefficients. We show, how in such theories an effective right-handed Majorana neutrino mass can be generated at two loops by gravitational interactions that involve global anomalies related to quantum torsion. We estimate the magnitude of the gravitationally induced Majorana mass and find that it is highly model dependent, ranging from multi-TeV to...

  1. Spacetime Dynamics from Spin Dynamics: Cosmological Constant and Neutrino Mass

    Science.gov (United States)

    Crawford, James

    2003-04-01

    Two fundamental unresolved issues in gravitational physics are the origin of the cosmological constant (dark energy), whose existence is suggested by the observed acceleration of the universe, and the origin of the particle masses, which we now know includes the neutrinos. Since all matter particles are represented by spinor fields, it seems natural to inquire whether the gravitational interaction of the spinor fields can illuminate these issues. Therefore we consider the possibility that the spin curvature is fundamental, and show that by relaxing the Schrödinger condition (covariant constancy of the Dirac matrices) it is possible to obtain both spacetime curvature and torsion as parts of the spin curvature. We assume a scale invariant Lagrangian composed of the standard Yang-Mills Lagrangian for the spin curvature and the massless Dirac Lagrangian for the spinors. An exact vacuum cosmological solution to the associated field equations is found which exhibits exponential acceleration of the universe and gives a minimum mass for all spinors.

  2. Neutrino Mass and Mixing: from Theory to Experiment

    CERN Document Server

    King, Stephen F; Morisi, Stefano; Shimizu, Yusuke; Tanimoto, Morimitsu

    2014-01-01

    The origin of fermion mass hierarchies and mixings is one of the unresolved and most difficult problem in high-energy physics. One possibility to address the flavour problem is by extending the Standard Model to include a family symmetry. In the recent years it has become very popular to use non-Abelian discrete flavour symmetries because of their power in the prediction of the large leptonic mixing angles relevant for neutrino oscillation experiments. Here we give an introduction to the flavour problem and to discrete groups which have been used to attempt a solution for it. We review the current status of models in the light of the recent measurement of the reactor angle and we consider different model building directions taken. The use of the flavons or multi Higgs scalars in model building is discussed as well as the direct vs. indirect approaches. We also focus on the possibility to distinguish experimentally flavour symmetry models by means of mixing sum rules and mass sum rules. In fact, we illustrate ...

  3. Di-Higgs signatures from R-parity violating supersymmetry as the origin of neutrino mass

    CERN Document Server

    Biswas, Sanjoy; Sharma, Pankaj

    2016-01-01

    Motivated by the naturalness and neutrino mass generation, we study a bilinear R-parity violating supersymmetric scenario with a light Higgsino-like lightest supersymmetric particle (LSP). We observe that the LSP dominantly decays to $\

  4. Cosmological axion and neutrino mass constraints from Planck 2015 temperature and polarization data

    National Research Council Canada - National Science Library

    Di Valentino, Eleonora; Giusarma, Elena; Lattanzi, Massimiliano; Mena, Olga; Melchiorri, Alessandro; Silk, Joseph

    2016-01-01

    .... Therefore, relic axions constitute a hot dark matter component and their masses are strongly degenerate with those of the three active neutrinos, as they leave identical signatures in the different...

  5. Is the observability of sterile neutrino masses consistent with $\

    CERN Document Server

    Ehrlich, R

    2016-01-01

    It is shown that a 1980 proposal to search for heavy sterile neutrinos by observing the energy of the associated lepton in weak decays rests on an questionable assumption, and that the possibility of such a detection might be inconsistent with the observability of neutrino oscillations.

  6. LHC phenomenology of a two-Higgs-doublet neutrino mass model

    OpenAIRE

    Davidson, Shainen M.; Logan, Heather E.

    2010-01-01

    We study the LHC search prospects for a model in which the neutrinos obtain Dirac masses from couplings to a second Higgs doublet with tiny vacuum expectation value. The model contains a charged Higgs boson that decays to l nu with branching fractions controlled by the neutrino masses and mixing angles as measured in neutrino oscillation experiments. The most promising signal is electroweak production of H+ H- pairs with decays to l l' pTmiss, where l l' = e+ e-, mu+ mu-, and e+- mu-+. We fin...

  7. A Lower Bound on Neutrino Mass And Its Implication on the Z-Burst Scenario

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Kwang-Chang; /Taiwan, Natl. Taiwan U.; Chen, Pisin; /KIPAC, Menlo Park

    2006-01-11

    We show that the cascade limit on ultra high energy cosmic neutrino (UHEC/nu) flux imposes a lower bound on the neutrino mass provided that super-GZK events of ultra high energy cosmic rays (UHECRs) are produced from Z-bursts. Based on the data from HiRes and AGASA, the obtained neutrino mass lower bound violates its existing cosmological upper bound. We conclude that the Z-burst cannot be the dominant source for the observed super-GZK UHECR events. This is consistent with the recent ANITA-lite data.

  8. Constraints on the neutrino mass and mass hierarchy from cosmological observations

    Science.gov (United States)

    Huang, Qing-Guo; Wang, Ke; Wang, Sai

    2016-09-01

    Considering the mass splitting between three active neutrinos, we represent the new constraints on the sum of neutrino mass sum m_ν by updating the anisotropic analysis of the Baryon Acoustic Oscillation (BAO) scale in the CMASS and LOWZ galaxy samples from Data Release 12 of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS DR12). Combining the BAO data of 6dFGS, MGS, LOWZ and CMASS with it{Planck} 2015 data of temperature anisotropy and polarizations of the Cosmic Microwave Background (CMB), we find that the 95 % C.L. upper bounds on sum m_ν refer to sum m_{ν ,NH}<0.18 eV for the normal hierarchy (NH), sum m_{ν ,IH}<0.20 eV for the inverted hierarchy (IH) and sum m_{ν ,DH}<0.15 eV for the degenerate hierarchy (DH), respectively, and the normal hierarchy is slightly preferred over the inverted one (Δ χ ^2≡ χ ^2_NH-χ ^2_IH ˜eq -3.4). In addition, the additional relativistic degrees of freedom and massive sterile neutrinos are neither favored at present.

  9. Constraints on the neutrino mass and mass hierarchy from cosmological observations

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qing-Guo [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Wang, Ke; Wang, Sai [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China)

    2016-09-15

    Considering the mass splitting between three active neutrinos, we represent the new constraints on the sum of neutrino mass sum m{sub ν} by updating the anisotropic analysis of the Baryon Acoustic Oscillation (BAO) scale in the CMASS and LOWZ galaxy samples from Data Release 12 of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS DR12). Combining the BAO data of 6dFGS, MGS, LOWZ and CMASS with Planck 2015 data of temperature anisotropy and polarizations of the Cosmic Microwave Background (CMB), we find that the 95 % C.L. upper bounds on sum m{sub ν} refer to sum m{sub ν,NH} < 0.18 eV for the normal hierarchy (NH), sum m{sub ν,IH} < 0.20 eV for the inverted hierarchy (IH) and sum m{sub ν,DH} < 0.15 eV for the degenerate hierarchy (DH), respectively, and the normal hierarchy is slightly preferred over the inverted one (Δχ{sup 2} ≡ χ{sup 2}{sub NH} - χ{sup 2}{sub IH} ≅ -3.4). In addition, the additional relativistic degrees of freedom and massive sterile neutrinos are neither favored at present. (orig.)

  10. Leptoquark patterns unifying neutrino masses, flavor anomalies, and the diphoton excess

    Science.gov (United States)

    Deppisch, F. F.; Kulkarni, S.; Päs, H.; Schumacher, E.

    2016-07-01

    Vector leptoquarks provide an elegant solution to a series of anomalies and at the same time generate naturally light neutrino masses through their mixing with the standard model Higgs boson. We present a simple Froggatt-Nielsen model to accommodate the B physics anomalies RK and RD , neutrino masses, and the 750 GeV diphoton excess in one cohesive framework adding only two vector leptoquarks and two singlet scalar fields to the standard model field content.

  11. Leptoquark patterns unifying neutrino masses, flavor anomalies and the diphoton excess

    CERN Document Server

    Deppisch, F F; Päs, H; Schumacher, E

    2016-01-01

    Vector leptoquarks provide an elegant solution to a series of anomalies and at the same time generate naturally light neutrino masses through their mixing with the standard model Higgs boson. We present a simple Froggatt-Nielsen model to accommodate the B physics anomalies $R_K$ and $R_D$, neutrino masses, and the $750\\,$GeV diphoton excess in one cohesive framework adding only two vector leptoquarks and two singlet scalar fields to the standard model field content.

  12. Baryon asymmetry via leptogenesis in a neutrino mass model with complex scaling

    Science.gov (United States)

    Samanta, Rome; Chakraborty, Mainak; Roy, Probir; Ghosal, Ambar

    2017-03-01

    Baryogenesis via leptogenesis is investigated in a specific model of light neutrino masses and mixing angles. The latter was proposed on the basis of an assumed complex-extended scaling property of the neutrino Majorana mass matrix Mν, derived with a type-1 seesaw from a Dirac mass matrix mD and a heavy singlet neutrino Majorana mass matrix MR. One of its important features, highlighted here, is that there is a common source of the origin of a nonzero θ13 and the CP violating lepton asymmetry through the imaginary part of mD. The model predicted CP violation to be maximal for the Dirac type and vanishing for the Majorana type. We assume strongly hierarchical mass eigenvalues for MR. The leptonic CP asymmetry parameter εα1 mm with lepton flavor α, originating from the decays of the lightest of the heavy neutrinos N1 (of mass M1) at a temperature T ~ M1, is what matters here with the lepton asymmetries, originating from the decays of N2,3, being washed out. The light leptonic and heavy neutrino number densities (normalized to the entropy density) are evolved via Boltzmann equations down to electroweak temperatures to yield a baryon asymmetry through sphaleronic transitions. The effects of flavored vs. unflavored leptogenesis in the three mass regimes (1) M1 1012 GeV are numerically worked out for both a normal and an inverted mass ordering of the light neutrinos. Corresponding results on the baryon asymmetry of the universe are obtained, displayed and discussed. For values close to the best-fit points of the input neutrino mass and mixing parameters, obtained from neutrino oscillation experiments, successful baryogenesis is achieved for the mass regime (2) and a normal mass ordering of the light neutrinos with a nonzero θ13 playing a crucial role. However, the other possibility of an inverted mass ordering for the same mass regime, though disfavored, cannot be excluded. A discussion is also given on the sensitivity of our result to the masses M2,3 of the

  13. Measurement of the Top Quark Mass in Dilepton Final States with the Neutrino Weighting Method

    Energy Technology Data Exchange (ETDEWEB)

    Ilchenko, Yuriy [Southern Methodist Univ., Dallas, TX (United States)

    2012-12-15

    The top quark is the heaviest fundamental particle observed to date. The mass of the top quark is a free parameter in the Standard Model (SM). A precise measurement of its mass is particularly important as it sets an indirect constraint on the mass of the Higgs boson. It is also a useful constraint on contributions from physics beyond the SM and may play a fundamental role in the electroweak symmetry breaking mechanism. I present a measurement of the top quark mass in the dilepton channel using the Neutrino Weighting Method. The data sample corresponds to an integrated luminosity of 4.3 fb-1 of p$\\bar{p}$ collisions at Tevatron with √s = 1.96 TeV, collected with the DØ detector. Kinematically under-constrained dilepton events are analyzed by integrating over neutrino rapidity. Weight distributions of t$\\bar{t}$ signal and background are produced as a function of the top quark mass for different top quark mass hypotheses. The measurement is performed by constructing templates from the moments of the weight distributions and input top quark mass, followed by a subsequent likelihood t to data. The dominant systematic uncertainties from jet energy calibration is reduced by using a correction from `+jets channel. To replicate the quark avor dependence of the jet response in data, jets in the simulated events are additionally corrected. The result is combined with our preceding measurement on 1 fb-1 and yields mt = 174.0± 2.4 (stat.) ±1.4 (syst.) GeV.

  14. The Lma MSW Solution of the Solar Neutrino Problem, Inverted Neutrino Mass Hierarchy and Reactor Neutrino Experiments

    CERN Document Server

    Petcov, S T

    2002-01-01

    In the context of three-neutrino oscillations, we study the possibility of using antineutrinos from nuclear reactors to explore the $10^-4 eV^2 < \\Delta m^2_{\\odot} \\ltap 8\\times 10^-4 eV^2$ region of the LMA MSW solution of the solar neutrino problem. The KamLAND experiment is not expected to determine $\\Delta m^2_{\\odot}$ if the latter happens to lie in the indicated region. By analysing both the total event rate suppression and the energy spectrum distortion caused by $\\bar{\

  15. Measurement of the neutrino mass splitting and flavor mixing by MINOS

    CERN Document Server

    Adamson, P; Armstrong, R; Auty, D J; Ayres, D S; Backhouse, C; Barr, G; Bishai, M; Blake, A; Bock, G J; Boehnlein, D J; Bogert, D; Cavanaugh, S; Cherdack, D; Childress, S; Choudhary, B C; Coelho, J A B; Coleman, S J; Corwin, L; Cronin-Hennessy, D; Danko, I Z; de Jong, J K; Devenish, N E; Diwan, M V; Dorman, M; 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; Grant, N; Grzelak, K; Habig, A; Harris, D; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Huang, X; Hylen, J; Ilic, J; Irwin, G M; Isvan, Z; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kopp, S; Kordosky, M; Kreymer, A; Lang, K; Lefeuvre, G; Ling, J; Litchfield, P J; Litchfield, R P; Loiacono, L; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGowan, A M; Mehdiyev, R; Meier, J R; Messier, M D; Michael, D G; Miller, W H; Mishra, S R; Mitchell, J; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nowak, J A; Oliver, W P; Orchanian, M; Ospanov, R; Paley, J; Patterson, R B; Pawloski, G; Pearce, G F; Petyt, D A; Phan-Budd, S; Plunkett, R K; Qiu, X; Ratchford, J; Raufer, T M; Rebel, B; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Sanchez, M C; Schneps, J; Schreiner, P; Shanahan, P; Smith, C; Sousa, A; Stamoulis, P; Strait, M; Tagg, N; Talaga, R L; Thomas, J; Thomson, M A; Tinti, G; Toner, R; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Weber, A; Webb, R C; White, C; Whitehead, L; Wojcicki, S G; Yang, T; Zwaska, R

    2011-01-01

    Measurements of neutrino oscillations using the disappearance of muon neutrinos from the Fermilab NuMI neutrino beam as observed by the two MINOS detectors are reported. New analysis methods have been applied to an enlarged data sample from an exposure of $7.25 \\times 10^{20}$ protons on target. A fit to neutrino oscillations yields values of $|\\Delta m^2| = (2.32^{+0.12}_{-0.08})\\times10^{-3}$\\,eV$^2$ for the atmospheric mass splitting and $\\rm \\sin^2\\!(2\\theta) > 0.90$ (90%\\,C.L.) for the mixing angle. Pure neutrino decay and quantum decoherence hypotheses are excluded at 7 and 9 standard deviations, respectively.

  16. Impact of the first SNO results on Neutrino Mass and Mixing

    CERN Document Server

    Bandyopadhyay, A; Goswami, S; Kar, K; Choubey, Sandhya; Goswami, Srubabati; Kar, Kamales

    2001-01-01

    We investigate the implications of the SNO charged-current (CC) and electron scattering (ES) measurements of solar $^8B$ neutrino fluxes for neutrino mass and mixing parameters by performing a global and unified $\\chi^2$ analysis of the solar neutrino data incorporating the first SNO results along with the results from Cl, Ga and SuperKamiokande(SK) on the total flux of neutrinos as well as the recoil electron spectrum observed at SK and the CC spectrum observed at SNO in the framework of two neutrino mixing. We determine the best-fit values of the parameters, the $\\chi^2_{min}$ and the goodness of fit of various oscillation solutions for both $\

  17. Measurement of the neutrino mass splitting and flavor mixing by MINOS.

    Science.gov (United States)

    Adamson, P; Andreopoulos, C; Armstrong, R; Auty, D J; Ayres, D S; Backhouse, C; Barr, G; Bishai, M; Blake, A; Bock, G J; Boehnlein, D J; Bogert, D; Cavanaugh, S; Cherdack, D; Childress, S; Choudhary, B C; Coelho, J A B; Coleman, S J; Corwin, L; Cronin-Hennessy, D; Danko, I Z; de Jong, J K; Devenish, N E; Diwan, M V; Dorman, M; 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; Grant, N; Grzelak, K; Habig, A; Harris, D; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Huang, X; Hylen, J; Ilic, J; Irwin, G M; Isvan, Z; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kopp, S; Kordosky, M; Kreymer, A; Lang, K; Lefeuvre, G; Ling, J; Litchfield, P J; Litchfield, R P; Loiacono, L; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGowan, A M; Mehdiyev, R; Meier, J R; Messier, M D; Michael, D G; Miller, W H; Mishra, S R; Mitchell, J; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nowak, J A; Oliver, W P; Orchanian, M; Ospanov, R; Paley, J; Patterson, R B; Pawloski, G; Pearce, G F; Petyt, D A; Phan-Budd, S; Plunkett, R K; Qiu, X; Ratchford, J; Raufer, T M; Rebel, B; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Sanchez, M C; Schneps, J; Schreiner, P; Shanahan, P; Smith, C; Sousa, A; Stamoulis, P; Strait, M; Tagg, N; Talaga, R L; Thomas, J; Thomson, M A; Tinti, G; Toner, R; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Weber, A; Webb, R C; White, C; Whitehead, L; Wojcicki, S G; Yang, T; Zwaska, R

    2011-05-01

    Measurements of neutrino oscillations using the disappearance of muon neutrinos from the Fermilab NuMI neutrino beam as observed by the two MINOS detectors are reported. New analysis methods have been applied to an enlarged data sample from an exposure of 7.25×10(20) protons on target. A fit to neutrino oscillations yields values of |Δm(2)|=(2.32(-0.08)(+0.12))×10(-3) eV(2) for the atmospheric mass splitting and sin(2)(2θ)>0.90 (90% C.L.) for the mixing angle. Pure neutrino decay and quantum decoherence hypotheses are excluded at 7 and 9 standard deviations, respectively.

  18. Neutrino Oscillations With Two Sterile Neutrinos

    Science.gov (United States)

    Kisslinger, Leonard S.

    2016-10-01

    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.

  19. Neutrino Oscillations With Two Sterile Neutrinos

    CERN Document Server

    Kisslinger, Leonard S

    2016-01-01

    This work estimates the probability of $\\mu$ to $e$ neutrino oscillation with two sterile neutrinos using a 5x5 U-matrix, an extension of the previous estimate with one sterile neutrino and a 4x4 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.

  20. Physical effects involved in the measurements of neutrino masses with future cosmological data

    CERN Document Server

    Archidiacono, Maria; Lesgourgues, Julien; Poulin, Vivian

    2016-01-01

    Future Cosmic Microwave Background experiments together with upcoming galaxy and 21-cm surveys will provide extremely accurate measurements of different cosmological observables located at different epochs of the cosmic history. The new data will be able to constrain the neutrino mass sum with the best precision ever. In order to exploit the complementarity of the different redshift probes, a deep understanding of the physical effects driving the impact of massive neutrinos on CMB and large scale structures is required. The goal of this work is to describe these effects, assuming a summed neutrino mass close to its minimum allowed value. We find that parameter degeneracies can be removed by appropriate combinations, leading to robust and model independent constraints. A joint forecast of the sensitivity of Euclid and DESI surveys together with a CORE-like CMB experiment leads to a $1\\sigma$ uncertainty of $7$~meV on the summed neutrino mass. However this particular combination gives rise to a peculiar degener...

  1. Neutrino masses in RPV models with two pairs of Higgs doublets

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, Yuval [Laboratory for Elementary-Particle Physics, Cornell University,Ithaca, N.Y. (United States); Peset, Clara [Institut de Fisica d’Altes Energies (IFAE), Universitat Autònoma de Barcelona,08193 Bellaterra, Barcelona (Spain)

    2014-04-07

    We study the generation of neutrino masses and mixing in supersymmetric R-parity violating models containing two pairs of Higgs doublets. In these models, new RPV terms H^{sub D{sub 1}}H^{sub D{sub 2}}E^ arise in the superpotential, as well as new soft terms. Such terms give new contributions to neutrino masses. We identify the different parameters and suppression/enhancement factors that control each of these contributions. At tree level, just like in the MSSM, only one neutrino acquires a mass due to neutrino-neutralino mixing. There are no new one loop effects. We study the two loop contributions and find the conditions under which they can be important.

  2. Neutrino masses in RPV models with two pairs of Higgs doublets

    CERN Document Server

    Grossman, Yuval

    2014-01-01

    We study the generation of neutrino masses and mixing in supersymmetric R-parity violating models containing two pairs of Higgs doublets. In these models, new RPV terms $\\hat H_{D_1} \\hat H_{D_2} \\hat E$ arise in the superpotential, as well as new soft terms. Such terms give new contributions to neutrino masses. We identify the different parameters and suppression/enhancement factors that control each of these contributions. At tree level, just like in the MSSM, only one neutrino acquires a mass due to neutrino-neutralino mixing. There are no new one loop effects. We study the two loop contributions and find the conditions under which they can be important.

  3. Neutrino masses in $SU(5)\\times U(1)_F$ with adjoint flavons

    CERN Document Server

    Nardi, Enrico; Velasquez, Mauricio

    2011-01-01

    We present a $SU(5)\\times U(1)_F$ supersymmetric model for neutrino masses and mixings that includes three heavy singlet neutrinos and two flavons. We discuss how Abelian $U(1)_F$ symmetries can naturally yield non-hierarchical light neutrinos even when the heavy states are strongly hierarchical, and how it can also ensure that $R$--parity arises as an exact accidental symmetry. By assigning flavons to the adjoint representation of SU(5) and assuming universality for all the fundamental couplings, the coefficients of the effective Yukawa and Majorana mass operators become calculable in terms of group theoretical quantities. There is a single free parameter in the model, however, at leading order the structure of the light neutrinos mass matrix is determined in a parameter independent way.

  4. Radiative Neutrino Masses in a SUSY GUT Model

    CERN Document Server

    Koide, Y

    2003-01-01

    Radiatively-induced neutrino mass matrix is investigated within the framework of an SU(5) SUSY GUT model. The model has matter fields of three families \\bar{5}_{L(+)i}+5_{L(+)i} in addition to the ordinary matter fields \\bar{5}_{L(-)i}+10_{L(+)i} and Higgs fields H_{(+)}+\\bar{H}_{(0)}, where (+,0,-) denote the transformation properties (\\omega^{+1},\\omega^0,\\omega^{-1}) (\\omega^3=-1) under a discrete symmetry Z_3. R-parity violating terms are given by \\bar{5}_{L(+)} \\bar{5}_{L(+)} 10_{L(+)}, while the Yukawa interactions are given by \\bar{H}_{(0)} \\bar{5}_{L(-)} 10_{L(+)}, i.e. the \\bar{5}-fields in both are different from each other. The Z_3 symmetry is only broken by the terms \\bar{5}_{L(+)i}5_{L(+)i} softly, so that the \\bar{5}_{L(+)i}\\leftrightarrow \\bar{5}_{L(-)i} mixings appear at \\mu < M_X. Of the R-parity violating terms \\bar{5}_{L(+)} \\bar{5}_{L(+)} 10_{L(+)}, only the terms (e_L\

  5. Particle quantum states with indefinite mass and neutrino oscillations

    CERN Document Server

    Lobanov, A E

    2015-01-01

    Spaces of particle states are constructed in such a way that charged leptons, neutrinos, as well as down- and up-type quarks are combined in multiplets with their components being considered as different quantum states of a single particle. In the theory based on the Lagrangian of fermion sector of the Standard Model modified with this approach the phenomenon of neutrino oscillations appears. By example of pion decay it is shown that the states of the neutrino, arising in the process of decay may be described by a superposition of states with identical momenta with very high accuracy.

  6. Supernova Neutrino Detection

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Botella, Ines, E-mail: ines.gil@ciemat.es [CIEMAT, Basic Research Department, Avenida Complutense, 22, 28040 Madrid (Spain)

    2011-07-25

    The neutrino burst from a core collapse supernova can provide information about the explosion mechanism and the mechanisms of proto neutron star cooling but also about the intrinsic properties of the neutrino such as flavor oscillations. One important question is to understand to which extend can the supernova and the neutrino physics be decoupled in the observation of a single supernova. The possibility to probe the neutrino mixing angle {theta}{sub 13} and the type of mass hierarchy from the detection of supernova neutrinos with liquid argon detectors is discussed in this paper. Moreover, a quantitatively study about the possibility to constrain the supernova parameters is presented. A very massive liquid argon detector ({approx} 100 kton) is needed to perform accurate measurements of these parameters. Finally the possible detection of the diffuse supernova neutrino background in liquid argon detectors is also described.

  7. Physics of neutrino flavor transformation through matter–neutrino resonances

    Directory of Open Access Journals (Sweden)

    Meng-Ru Wu

    2016-01-01

    Full Text Available In astrophysical environments such as core-collapse supernovae and neutron star–neutron star or neutron star–black hole mergers where dense neutrino media are present, matter–neutrino resonances (MNRs can occur when the neutrino propagation potentials due to neutrino–electron and neutrino–neutrino forward scattering nearly cancel each other. We show that neutrino flavor transformation through MNRs can be explained by multiple adiabatic solutions similar to the Mikheyev–Smirnov–Wolfenstein mechanism. We find that for the normal neutrino mass hierarchy, neutrino flavor evolution through MNRs can be sensitive to the shape of neutrino spectra and the adiabaticity of the system, but such sensitivity is absent for the inverted hierarchy.

  8. Higgs production through sterile neutrinos

    Science.gov (United States)

    Antusch, Stefan; Cazzato, Eros; Fischer, Oliver

    2016-10-01

    In scenarios with sterile (right-handed) neutrinos with an approximate “lepton-number-like” symmetry, the heavy neutrinos (the mass eigenstates) can have masses around the electroweak scale and couple to the Higgs boson with, in principle, unsuppressed Yukawa couplings, while the smallness of the light neutrinos’ masses is guaranteed by the approximate symmetry. The on-shell production of the heavy neutrinos at lepton colliders, together with their subsequent decays into a light neutrino and a Higgs boson, constitutes a resonant contribution to the Higgs production mechanism. This resonant mono-Higgs production mechanism can contribute significantly to the mono-Higgs observables at future lepton colliders. A dedicated search for the heavy neutrinos in this channel exhibits sensitivities for the electron neutrino Yukawa coupling as small as ˜ 5 × 10-3. Furthermore, the sensitivity is enhanced for higher center-of-mass energies, when identical integrated luminosities are considered.

  9. Jet Luminosity of Gamma-ray Bursts: Blandford-Znajek Mechanism v.s. Neutrino Annihilation Process

    CERN Document Server

    Liu, Tong; Xue, Li; Gu, Wei-Min

    2015-01-01

    A neutrino-dominated accretion flow (NDAF) around a rotating stellar-mass black hole (BH) is one of the plausible candidates for the central engine of gamma-ray bursts (GRBs). Two mechanisms, i.e., Blandford-Znajek (BZ) mechanism and neutrino annihilation process, are generally considered to power GRBs. Using the analytic solutions from Xue et al. (2013) and ignoring the effects of the magnetic field configuration, we estimate the BZ and neutrino annihilation luminosities as the functions of the disk masses and BH spin parameters to contrast the observational jet luminosities of GRBs. The results show that, although the neutrino annihilation processes could account for most of GRBs, the BZ mechanism is more effective, especially for long-duration GRBs. Actually, if the energy of afterglows and flares of GRBs is included, the distinction between these two mechanisms is more significant. Furthermore, massive disk mass and high BH spin are beneficial to power high luminosities of GRBs. Finally, we discuss possib...

  10. Dirac or Majorana nature and mass effects on the neutrino behaviour; Effets de la nature de Dirac ou de Majorana, ainsi que de la masse, sur le comportement du neutrino

    Energy Technology Data Exchange (ETDEWEB)

    Campagne, J.E.

    1995-04-01

    This work deals with the Dirac or Majorana nature and mass effects on the neutrino behaviour. In the first part of this study are given the Dirac equation properties and the Majorana neutrino definition. As the difference between a Dirac and a Majorana neutrino has only a sense if their masses are not equal to zero, the second part presents a generalization of the Dirac mass term and the different ways to generate a neutrino mass. Several comparisons are made in the third part between quarks and leptons families mixtures which are linked intimately to masses generation. The fourth part gives an example of masses possible values and neutrinos particles mixtures matrix elements predicting. The neutrino electromagnetic and weak interactions are then considered as well as the neutrinos production by the neutral currents. The charged currents are however better to discriminate the Dirac or Majorana nature. The neutrinos propagation in the matter and in the vacuum are analyzed (the case of neutrino oscillations more particularly) under the result of recent experimental observations. At last, are presented the evaluation of neutrino mass (if it exists) through the analysis of double beta decay and the sensibility of future experiments. (O.L.). 164 refs., 73 figs., 20 tabs.

  11. Neutrino masses from SUSY breaking in radiative seesaw models

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Antonio J.R. [University of Lisbon, Centro de Fisica Teorica de Particulas (CFTP), Instituto Superior Tecnico, Lisbon (Portugal)

    2015-03-01

    Radiatively generated neutrino masses (m{sub ν}) are proportional to supersymmetry (SUSY) breaking, as a result of the SUSY non-renormalisation theorem. In this work, we investigate the space of SUSY radiative seesaw models with regard to their dependence on SUSY breaking (SUSY). In addition to contributions from sources of SUSY that are involved in electroweak symmetry breaking (SUSY{sub EWSB} contributions), and which are manifest from left angle F{sub H}{sup †} right angle = μ left angle anti H right angle ≠ 0 and left angle D right angle = g sum {sub H} left angle H{sup †} x {sub H} H right angle ≠ 0, radiatively generated m{sub ν} can also receive contributions from SUSY sources that are unrelated to EWSB (SUSY{sub EWS} contributions). We point out that recent literature overlooks pure-SUSY{sub EWSB} contributions (∝ μ/M) that can arise at the same order of perturbation theory as the leading order contribution from SUSY{sub EWS}. We show that there exist realistic radiative seesaw models in which the leading order contribution to m{sub ν} is proportional to SUSY{sub EWS}. To our knowledge no model with such a feature exists in the literature. We give a complete description of the simplest model topologies and their leading dependence on SUSY. We show that in one-loop realisations LLHH operators are suppressed by at least μ m{sub soft}/M{sup 3} or m{sub soft}{sup 2}/M{sup 3}. We construct a model example based on a oneloop type-II seesaw. An interesting aspect of these models lies in the fact that the scale of soft-SUSY effects generating the leading order m{sub ν} can be quite small without conflicting with lower limits on the mass of new particles. (orig.)

  12. Neutrino-Triggered Asymmetric Magnetorotational Pulsar Natal Kick Cherry-Stone Shooting" Mechanism)

    Science.gov (United States)

    Kuznetsov, A. V.; Mikheev, N. V.

    2013-11-01

    The sterile neutrino mechanisms for natal neutron stars kicks are re-analyzed. It is shown that the magnetic field strengths needed for a kick were underestimated essentially. Another mechanism with standard neutrinos is discussed where the outgoing neutrino flux in a supernova explosion with a strong toroidal magnetic field generation causes the field redistribution in "upper" and "lower" hemispheres of the supernova envelope. The resulting magnetic field pressure asymmetry causes the pulsar natal kick.

  13. An $A_4$ realization of inverse seesaw: neutrino masses, $\\theta_{13}$ and leptonic non-unitarity

    CERN Document Server

    Karmakar, Biswajit

    2016-01-01

    We provide an $A_4$ based flavor symmetric scenario to accommodate the inverse seesaw mechanism for explaining light neutrino masses and mixing. We find that the lepton mixing, in particular the tri-bimaximal mixing pattern and its deviation through nonzero $\\theta_{13}$, is originated solely from the flavor structure of the lepton number violating contribution of the neutral lepton mass matrix. Here we discuss in detail how a nonzero value of $\\theta_{13}$ is correlated with the other parameters in the framework and its impact on the Dirac CP phase $\\delta$. We also analyze the non-unitarity effects on lepton mixing matrix and its implication in terms of the lepton flavor violating decays, etc..

  14. Neutrino mass patterns, -parity violating supersymmetry and associated phenomenology

    Indian Academy of Sciences (India)

    Biswarup Mukhopadhyaya

    2000-01-01

    Motivated by the recent super-Kamiokande results on atmospheric neutrinos, we incorporate massive neutrinos, with large angle oscillation between the second and third generations, in a theory with -parity violating supersymmetry. The general features of such a theory are briefly reviewed. We emphasize its testability through the observation of comparable numbers of muons and taus, produced together with the -boson, in decays of the lightest neutralino. A distinctly measurable decay gap is anotherremarkable feature of such a scenario.

  15. Space-Like Motions of Quantum Zero Mass Neutrinos

    CERN Document Server

    Widom, A; Srivastava, Y N

    2011-01-01

    Recent experimental reports of super-luminal velocity neutrinos moving between Geneva and Gran Sasso in no way contradict the special relativity considerations of conventional quantum field theory. A neutrino exchanged between Geneva and Gran Sasso is both virtual and space-like. The Lorentz invariant space-like distance $L$ and the Lorentz invariant space-like four momentum transfered $\\varpi $ between Geneva and Gran Sasso can be extracted from experimental data as will be shown in this work.

  16. Effect of atmospheric flux uncertainties on the determination of the neutrino mass hierarchy

    Directory of Open Access Journals (Sweden)

    Sandroos Joakim

    2016-01-01

    Full Text Available The next generation of large-volume neutrino telescopes will include low-energy subarrays which will be able to measure neutrinos with energies of a few GeV. In this energy range the primary signal below the horizon is neutrinos created by cosmic ray interactions in the atmosphere. The measured event rate will depend on the neutrino mass hierarchy, allowing determination of this quantity to a significance level of about 3.5 sigma within a 5-year period, mostly limited by systematic uncertainties. We present here the impact of the uncertainties on the atmospheric neutrino flux normalization on the determination of the neutrino mass hierarchy. We suggest constraining the systematic uncertainties by including the downgoing neutrino sample, which will increase the significance. This work was performed using simulation data from the low-energy extension to the IceCube detector located at the geographic south pole, PINGU, and is relevant to a wide range of other experiments.

  17. Atmospheric neutrinos and discovery of neutrino oscillations.

    Science.gov (United States)

    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.

  18. Neutrino sector with Majorana mass terms and Friedberg-Lee symmetry

    Science.gov (United States)

    Jarlskog, C.

    2008-04-01

    We examine a recently proposed symmetry/condition by Friedberg and Lee in a framework where three right-handed neutrinos are added to the spectrum of the three-family minimal standard model. It is found that the right-handed neutrinos are very special, with respect to this symmetry. In the symmetry limit the neutrinos are massless, which could possibly be a hint about why they are light. Imposed as a condition and not as a full symmetry, we find that one of the three right-handed neutrinos simply decouples (has only gravitational interactions) and one of the interacting neutrinos is massless. The possible relation of the model to the seesaw mechanism is briefly discussed.

  19. Neutrino Sector with Majorana Mass Terms and Friedberg-Lee Symmetry

    CERN Document Server

    Jarlskog, C

    2007-01-01

    We examine a recently proposed symmetry/condition by Friedberg and Lee in the framework where three right-handed neutrinos are added to the spectrum of the three-family Minimal Standard Model. It is found that the right-handed neutrinos are very special, with respect to this symmetry. In the symmetry limit the neutrinos are massless and that may be a hint about why they are light. Imposed as a condition and not as a full symmetry, we find that one of the three right-handed neutrinos simply decouples (has only gravitational interactions) and that there is a massless interacting neutrino. The possible relation of the model to the see-saw mechanism is briefly discussed.

  20. Neutrino mass bounds from neutrinoless double beta-decays and cosmological probes

    Indian Academy of Sciences (India)

    Yong-Yeon Keum

    2016-02-01

    We investigate the way the total mass sum of neutrinos can be constrained from the neutrinoless double beta-decay and cosmological probes with cosmic microwave background (CMBR), large-scale structures including 2dFGRS and SDSS datasets. First we discuss, in brief, the current status of neutrino mass bounds from neutrino beta decays and cosmic constraint within the flat CMD model. In addition, we explore the interacting neutrino dark-energy model, where the evolution of neutrino masses is determined by quintessence scalar field, which is responsible for cosmic acceleration. Assuming the flatness of the Universe, the constraint we can derive from the current observation is < 0.87 eV at 95% confidence level, which is consistent with < 0.68 eV in the flat CDM model without Lyman alpha forest data. In the presence of Lyman- forest data, interacting dark-energy models prefer a weaker bound < 0.43 eV to < 0.17 eV (Seljark et al). Finally, we discuss the future prospect of the neutrino mass bound with weak-lensing effects.

  1. Experimental conditions for determination of the neutrino mass hierarchy with reactor antineutrinos

    Science.gov (United States)

    Pac, Myoung Youl

    2016-01-01

    This article reports the optimized experimental requirements to determine neutrino mass hierarchy using electron antineutrinos (νbare) generated in a nuclear reactor. The features of the neutrino mass hierarchy can be extracted from the | Δ m312 | and | Δ m322 | oscillations by applying the Fourier sine and cosine transforms to the L / E spectrum. To determine the neutrino mass hierarchy above 90% probability, the requirements on the energy resolution as a function of the baseline are studied at sin2 ⁡ 2θ13 = 0.1. If the energy resolution of the neutrino detector is less than 0.04 /√{Eν} and the determination probability obtained from Bayes' theorem is above 90%, the detector needs to be located around 48-53 km from the reactor(s) to measure the energy spectrum of νbare. These results will be helpful for setting up an experiment to determine the neutrino mass hierarchy, which is an important problem in neutrino physics.

  2. Determining the Neutrino Mass Hierarchy with INO, T2K, NOvA and Reactor Experiments

    CERN Document Server

    Ghosh, Anushree; Choubey, Sandhya

    2012-01-01

    The relatively large measured value of $\\theta_{13}$ has opened up the possibility of determining the neutrino mass hierarchy through earth matter effects. Amongst the current accelerator-based experiments only NOvA has a long enough baseline to observe earth matter effects. However, NOvA is plagued with uncertainty on the knowledge of the true value of $\\delta_{CP}$, and this could drastically reduce its sensitivity to the neutrino mass hierarchy. The earth matter effect on atmospheric neutrinos on the other hand is almost independent of $\\delta_{CP}$. The 50 kton magnetized Iron CALorimeter at the India-based Neutrino Observatory (ICAL@INO) will be observing atmospheric neutrinos. The charge identification capability of this detector gives it an edge over others for mass hierarchy determination through observation of earth matter effects. We study in detail the neutrino mass hierarchy sensitivity of the data from this experiment simulated using the Nuance based generator developed for ICAL@INO and folded wi...

  3. Bilinear R-parity Violation and Small Neutrino Masses a Self-consistent Framework

    CERN Document Server

    Mira, J M; Restrepo, D A; Valle, José W F

    2000-01-01

    We study extensions of supersymmetric models without R-parity which include an anomalous U(1)_H horizontal symmetry. Bilinear R-parity violating terms induce a neutrino mass at tree level of approximately $(\\theta^2)^\\delta$ eV where $\\theta\\approx 0.22$ is the U(1)_H breaking parameter and $\\delta$ is an integer number that depends on the horizontal charges of the leptons. For $\\delta=1$ a unique self-consistent model arises in which i) all the superpotential trilinear R-parity violating couplings are forbidden by holomorphy; ii) the tree level neutrino mass falls in the range suggested by the atmospheric neutrino problem; iii) radiative contributions to neutrino masses are strongly suppressed resulting in a squared solar mass difference of few 10^{-8} eV^2 which only allows for the LOW (or quasi-vacuum) solution to the solar neutrino problem; iv) the neutrino mixing angles are not suppressed by powers of $\\theta$ and can naturally be large.

  4. Dark matter and lepton flavour violation in a hybrid neutrino mass model

    Energy Technology Data Exchange (ETDEWEB)

    Deppisch, Frank; Huang, Wei-Chih [Department of Physics and Astronomy, University College London,Gower Street, London (United Kingdom)

    2015-01-14

    We describe a hybrid model in which the light neutrino mass matrix receives both tree-level seesaw and loop-induced contributions. An additional U(1) gauge symmetry is used to stabilize the lightest right-handed neutrino as the Dark Matter candidate. After fitting the experimental neutrino data, we analyze and correlate the phenomenological consequences of the model, namely its impact on electroweak precision measurements, the Dark Matter relic abundance, lepton flavour violating rare decays and neutrinoless double beta decay. We find that natural realizations of the model characterized by large Yukawa couplings are compatible with and close to the current experimental limits.

  5. Neutrino mass hierarchy and $\\theta_{13}$ with a magic baseline beta-beam experiment

    CERN Document Server

    Agarwalla, S K; Raychaudhuri, Amitava K; Agarwalla, Sanjib Kumar; Choubey, Sandhya; Raychaudhuri, Amitava

    2006-01-01

    We underscore the physics advantage of an experiment where neutrinos produced in a beta-beam facility at CERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The CERN-INO distance is close to the so-called "magic" baseline which helps evade some of the parameter degeneracies and allows for a better measurement of the neutrino mass hierarchy and $\\theta_{13}$. We expound the possibility of using radioactive $^8B$ and $^{8}Li$ as the source isotopes for the $\

  6. The Effective Lagrangian for the Seesaw Model of Neutrino Mass and Leptogenesis

    CERN Document Server

    Broncano, A; Jenkins, E

    2003-01-01

    The effective Lagrangian for the seesaw model is derived including effects due to CP violation. Besides the usual dimension-5 operator responsible for light neutrino masses, a dimension-6 operator is obtained. For three or less heavy neutrino generations, the inclusion of both operators is necessary and sufficient for all independent physical parameters of the high-energy seesaw Lagrangian to appear in the low-energy effective theory, including the CP-odd phases relevant for leptogenesis. The dimension-6 operator implies exotic low-energy couplings for light neutrinos, providing a link between the high-energy physics and low-energy observables.

  7. The effective Lagrangian for the seesaw model of neutrino mass and leptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Broncano, A.; Gavela, M.B.; Jenkins, E

    2003-01-23

    The effective Lagrangian for the seesaw model is derived including effects due to CP-violation. Besides the usual dimension-5 operator responsible for light neutrino masses, a dimension-6 operator is obtained. For three or less heavy neutrino generations, the inclusion of both operators is necessary and sufficient for all independent physical parameters of the high-energy seesaw Lagrangian to appear in the low-energy effective theory, including the CP-odd phases relevant for leptogenesis. The dimension-6 operator implies exotic low-energy couplings for light neutrinos, providing a link between the high-energy physics and low-energy observables.

  8. Neutrino mass, dark matter and anomalous magnetic moment of muon in a U{(1)}_L{{}{_{μ}}}-{{}_L}{_{τ }} model

    Science.gov (United States)

    Biswas, Anirban; Choubey, Sandhya; Khan, Sarif

    2016-09-01

    The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local L μ - L τ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The L μ - L τ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The L μ - L τ gauge symmetry is known to be anomaly free and can explain the beyond SM measurement of the anomalous muon ( g - 2) through additional contribution arising from the extra Z μτ mediated diagram. Small neutrino masses are explained naturally through the Type-I seesaw mechanism, while the mixing angles are predicted to be in their observed ranges due to the broken L μ - L τ symmetry. The second complex scalar is shown to be stable and becomes the dark matter candidate in our model. We show that while the Z μτ portal is ineffective for the parameters needed to explain the anomalous muon ( g - 2) data, the correct dark matter relic abundance can easily be obtained from annihilation through the Higgs portal. Annihilation of the scalar dark matter in our model can also explain the Galactic Centre gamma ray excess observed by Fermi-LAT. We show the predictions of our model for future direct detection experiments and neutrino oscillation experiments.

  9. Low-mass right-handed neutrinos in the left-right symmetric theory

    Energy Technology Data Exchange (ETDEWEB)

    Gronau, M.; Yahalom, R.

    1984-04-09

    It is pointed out that the minimal left-right symmetric theory of the electroweak interactions based on SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) may accommodate right-handed neutrinos in the low-mass region of order 100 MeV or so, quite a few orders of magnitude below m(Wsub(R)). When an attempt is made to construct such a scheme, consistent with the present upper limits on the left-handed neutrino masses, one faces the problem of the evasion of the cosmological bound of 50 eV on ..nu..sub(..mu..L). We show that this constraint may be avoided in a somewhat simplified scheme based on reasonable gross scales which characterize the Dirac and Majorana parts of the neutrino mass matrix. In a detailed study of the neutrino mass matrix this is shown not to be possible when the neutrino Dirac masses are assumed to be of the order of magnitude of the corresponding charged lepton masses. A phenomenologically consistent scheme with m(..nu..sub(R)) approx.= O(100 MeV) based on Dirac masses of order 1/10 msub(e) is described. 34 references.

  10. Neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Deborah A.; /Fermilab

    2008-09-01

    The field of neutrino physics has expanded greatly in recent years with the discovery that neutrinos change flavor and therefore have mass. Although there are many neutrino physics results since the last DIS workshop, these proceedings concentrate on recent neutrino physics results that either add to or depend on the understanding of Deep Inelastic Scattering. They also describe the short and longer term future of neutrino DIS experiments.

  11. Quantum correction to tiny vacuum expectation value in two Higgs doublet model for Dirac neutrino mass

    CERN Document Server

    Morozumi, Takuya; Tamai, Kotaro

    2011-01-01

    We study a Dirac neutrino mass model of Davidson and Logan. In the model, the smallness of the neutrino mass is originated from the small vacuum expectation value of the second Higgs of two Higgs doublets. We study the one loop effective potential of the Higgs sector and examine how the small vacuum expectation is stable under the radiative correction. By deriving formulae of the radiative correction, we numerically study how large the one loop correction is and show how it depends on the quadratic mass terms and quartic couplings of the Higgs potential. The correction changes depending on the various scenarios for extra Higgs mass spectrum.

  12. Clustering, GUT scale and neutrino masses in Ultrahigh energy cosmic rays

    CERN Document Server

    Fodor, Z

    2002-01-01

    We determine the probability that an ultrahigh energy (above 5\\cdot 10^{19} eV) proton created at a distance r with energy E arrives at earth above a threshold E_c. The clustering of ultrahigh energy cosmic rays suggests that they might be emitted by compact sources. We present a statistical analysis on the source density based on the multiplicities. The ultrahigh energy cosmic ray spectrum is consistent with the decay of GUT scale particles. By using a maximum likelihood analysis we determine the mass of these GUT scale particles. We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. Based on this scenario we determine the required mass of the heaviest relic neutrino as well as the necessary ultrahigh energy cosmic neutrino flux via a maximum likelihood analysis.

  13. Neutrinos Masses in a Multi-Higgs Model with A4 symmetry

    Science.gov (United States)

    Machado, A. C. B.; Montero, J. C.; Pleitez, V.

    2012-08-01

    Presently it is well known that neutrino oscillation data are well described by massive neutrinos and their mixing. This suggests changes in the standard model (SM) and makes the flavor physics even more interesting. Recently, it has been proposed a multi-Higgs extension of the SM with Abelian and non-Abelian discrete symmetries which seeks to explain the origin of the masses and mixing matrices in all charge sectors.

  14. Discriminating neutrino mass models using Type-II see-saw formula

    Indian Academy of Sciences (India)

    N Nimal Singh; Mahadev Patagiri; Mrinal Kumar Das

    2006-02-01

    An attempt has been made to discriminate theoretically the three possible patterns of neutrino mass models,viz., degenerate, inverted hierarchical and normal hierachical models, within the framework of Type-II see-saw formula. From detailed numerical analysis we are able to arrive at a conclusion that the inverted hierarchical model with the same CP phase (referred to as Type [IIA]), appears to be most favourable to survive in nature (and hence most stable), with the normal hierarchical model (Type [III]) and inverted hierarchical model with opposite CP phase (Type [IIB]), follow next. The degenerate models (Types [IA,IB,IC]) are found to be most unstable. The neutrino mass matrices which are obtained using the usual canonical see-saw formula (Type I), and which also give almost good predictions of neutrino masses and mixings consistent with the latest neutrino oscillation data, are re-examined in the presence of the left-handed Higgs triplet within the framework of non-canonical see-saw formula (Type II). We then estimate a parameter (the so-called discriminator) which may represent the minimum degree of suppression of the extra term arising from the presence of left-handed Higgs triplet, so as to restore the good predictions on neutrino masses and mixings already acquired in Type-I see-saw model. The neutrino mass model is said to be favourable and hence stable when its canonical see-saw term dominates over the non-canonical (perturbative) term, and this condition is used here as a criterion for discriminating neutrino mass models.

  15. Measuring the mass hierarchy with muon and hadron events in atmospheric neutrino experiments

    Science.gov (United States)

    Ghosh, Anushree; Choubey, Sandhya

    2013-10-01

    Neutrino mass hierarchy can be measured in atmospheric neutrino experiments through the observation of earth matter effects. Magnetized iron calorimeters have been shown to be good in this regard due to their charge identification capabilities. The charged current interaction of ν μ in this detector, produces a muon track and a hadron shower. The direction of the muon track can be measured very accurately. We show the improvement expected in the reach of this class of experiments to the neutrino mass hierarchy, as we improve the muon energy resolution and the muon reconstruction efficiency. We next propose to include the hadron events in the analysis, by tagging them with the zenith angle of the corresponding muon and binning the hadron data first in energy and then in zenith angle. To the best of our knowledge this way of performing the analysis of the atmospheric neutrino data has not be considered before. We show that the hadron events increase the mass hierarchy sensitivity of the experiment. Finally, we show the expected mass hierarchy sensitivity in terms of the reconstructed neutrino energy and zenith angle. We show how the detector resolutions spoil the earth matter effects in the neutrino channel and argue why the sensitivity obtained from the neutrino analysis cannot be significantly better than that obtained from the analysis using muon data alone. As a result, the best mass hierarchy sensitivity is obtained when we add the contribution of the muon and the hadron data. For sin2 2 θ 13 = 0.1, sin2 θ 23 = 0.5, a muon energy resolution of 2%, reconstruction efficiency of 80% and exposure of 50 × 10 kton-year, we could get up to 4.5 σ signal for the mass hierarchy from combining the muon and hadron data. The signal will go up when the atmospheric data is combined with data from other existing experiments, particularly NO νA.

  16. Determining the neutrino mass hierarchy with INO, T2K, NOvA and reactor experiments

    Science.gov (United States)

    Ghosh, Anushree; Thakore, Tarak; Choubey, Sandhya

    2013-04-01

    The relatively large measured value of θ 13 has opened up the possibility of determining the neutrino mass hierarchy through earth matter effects. Amongst the current accelerator-based experiments only NOvA has a long enough baseline to observe earth matter effects. However, NOvA is plagued with uncertainty on the knowledge of the true value of δ CP, and this could drastically reduce its sensitivity to the neutrino mass hierarchy. The earth matter effect on atmospheric neutrinos on the other hand is almost independent of δ CP. The 50 kton magnetized Iron CALorimeter at the India-based Neutrino Observatory (ICAL@INO) will be observing atmospheric neutrinos. The charge identification capability of this detector gives it an edge over others for mass hierarchy determination through observation of earth matter effects. We study in detail the neutrino mass hierarchy sensitivity of the data from this experiment simulated using the NUANCE based generator developed for ICAL@INO and folded with the detector resolutions and efficiencies obtained by the INO collaboration from a full Geant4-based detector simulation. The data from ICAL@INO is then combined with simulated data from T2K, NOvA, Double Chooz, RENO and Daya Bay experiments and a combined sensitivity study to the mass hierarchy is performed. With 10 years of ICAL@INO data combined with T2K, NOvA and reactor data, one could get about 2.3 σ-5.7 σ discovery of the neutrino mass hierarchy, depending on the true value of sin2 θ 23 [0.4-0.6], sin2 2 θ 13 [0.08-0.12] and δ CP [0-2 π].

  17. Neutrino mass and signature from the dark matter in A1689

    CERN Document Server

    Nieuwenhuizen, Theodorus M

    2015-01-01

    The dark matter in the galaxy cluster Abell 1689 is modelled by isothermal neutrinos. New data on the $2d$ mass density allow an accurate description of its core and halo. There is no "missing baryon problem" and the baryons occur at the cosmic mass fraction beyond $2.1$ Mpc. Combining cluster and cosmic data leads to a solution of the dark matter riddle by left and right handed neutrinos with mass $(1.861 \\pm 0.016) h_{70}^{-2} eV/c^2$. Absence of neutrinoless double beta decay points to Dirac neutrinos: chargeless electrons with different flavor and mass eigenbases, 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.

  18. Neutrino physics

    CERN Document Server

    Hernandez, P

    2016-01-01

    This is the writeup of the lectures on neutrino physics delivered at various schools: TASI and Trieste in 2013 and the CERN-Latin American School in 2015. The topics discussed in this lecture include: general properties of neutrinos in the SM, the theory of neutrino masses and mixings (Dirac and Majorana), neutrino oscillations both in vacuum and in matter, as well as an overview of the experimental evidence for neutrino masses and of the prospects in neutrino oscillation physics. We also briefly review the relevance of neutri- nos in leptogenesis and in beyond-the-Standard-Model physics.

  19. Neutrino mass limits: robust information from the power spectrum of galaxy surveys

    CERN Document Server

    Cuesta, Antonio J; Verde, Licia

    2015-01-01

    We present cosmological upper limits on the sum of active neutrino masses using large-scale power spectrum data from the WiggleZ Dark Energy Survey and from the Sloan Digital Sky Survey - Data Release 7 (SDSS-DR7) sample of Luminous Red Galaxies (LRG). Combining measurements on the Cosmic Microwave Background temperature and polarisation anisotropies by the Planck satellite together with WiggleZ power spectrum results in a neutrino mass bound of 0.43 eV at 95% C.L., while replacing WiggleZ by the SDSS-DR7 LRG power spectrum, the 95% C.L. bound on the sum of neutrino masses improves to 0.17 eV. Adding Baryon Acoustic Oscillation (BAO) distance scale measurements, the neutrino mass upper limits greatly improve, since BAO data break degeneracies in parameter space. Within a $\\Lambda$CDM model, we find an upper limit of 0.11 eV (0.15 eV) at 95% C.L., when using SDSS-DR7 LRG (WiggleZ) together with BAO and Planck. The addition of BAO data makes the neutrino mass upper limit robust, showing only a weak dependence o...

  20. An upper limit on the $\\tau$ neutrino mass from three- and five-prong tau decays

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Becker, U; Bright-Thomas, P G; Casper, David William; Cattaneo, M; Cerutti, F; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Lehraus, Ivan; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Boccali, T; Focardi, E; Parrini, G; Zachariadou, K; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Stacey, A M; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Sloan, Terence; Williams, M I; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Diaconu, C A; Etienne, F; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Mannert, C; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Schune, M H; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Konstantinidis, N P; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G

    1998-01-01

    A bound on the tau neutrino mass is established using the data collected from 1991 to 1995 at Ecm = M(Z) with the ALEPH detector. Two separate limits are derived by fitting the distribution of visible energy vs invariant mass in tau+ -> pi+ pi+ pi- nu and tau+ -> pi+ pi+ pi- pi- pi+ (pi0) nu decays. The two results are combined to obtain a 95 % confidence level upper limit of 18.2 MeV/c^2 on the mass of the tau neutrino.

  1. Radiative Corrections to Light Neutrino Masses in Low Scale Type I Seesaw Scenarios and Neutrinoless Double Beta Decay

    CERN Document Server

    Lopez-Pavon, J; Petcov, S T

    2015-01-01

    We perform a detailed analysis of the one-loop corrections to the light neutrino mass matrix within low scale type I seesaw extensions of the Standard Model and their implications in experimental searches for neutrinoless double beta decay. We show that a sizable contribution to the effective Majorana neutrino mass from the exchange of heavy Majorana neutrinos is always possible, provided one requires a fine-tuned cancellation between the tree-level and one-loop contribution to the light neutrino masses. We quantify the level of fine-tuning as a function of the seesaw parameters and introduce a generalisation of the Casas-Ibarra parametrization of the neutrino Yukawa matrix, which easily allows to include the one-loop corrections to the light neutrino masses.

  2. Prospects for detecting Dark Matter with neutrino telescopes in Intermediate Mass Black Holes scenarios

    CERN Document Server

    Bertone, Gianfranco

    2006-01-01

    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 under-water 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.

  3. Neutrino-gaseous ''pancakes'' and the problem of hidden mass

    Energy Technology Data Exchange (ETDEWEB)

    Doroshkevich, A.G. (AN SSSR, Moscow. Inst. Prikladnoj Matematiki)

    1983-08-01

    Taking into account peculiar velocities of neutrinos the gaseous component is shown to dominate in the central part of a cosmological ''pancake'' (rhosub(p) > rhosub(..nu..)), while on the average anti rhosub(b) << anti rhosub(..nu..). Therefore fragmentation of a gaseous ''pancake'' and later clustering of the fragments into galaxies and groups of galaxies are determined by velocity distribution and gravity of the gaseous component. The hidden mass is formed by capture of neutrinos by clustering clouds. Formation of the cluster of galaxies is connected with perturbations embracing all the neutrino-gaseous ''pancake'', initial ratio of neutrino-to-gaseous densities being reestablished. It is shown that the first ''pancakes'' were formed at the red shifts z=5-8.

  4. Electrophobic Lorentz invariance violation for neutrinos and the see-saw mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, Sandhya; King, S.F

    2004-04-29

    We show how Lorentz invariance violation (LIV) can occur for Majorana neutrinos, without inducing LIV in the charged leptons via radiative corrections. Such 'electrophobic' LIV is due to the Majorana nature of the LIV operator together with electric charge conservation. Being free from the strong constraints coming from the charged lepton sector, electrophobic LIV can in principle be as large as current neutrino experiments permit. On the other hand, electrophobic LIV could be naturally small if it originates from LIV in some singlet 'right-handed neutrino' sector, and is felt in the physical left-handed neutrinos via a see-saw mechanism. We develop the formalism appropriate to electrophobic LIV for Majorana neutrinos, and discuss experimental constraints at current and future neutrino experiments.

  5. Electrophobic Lorentz invariance violation for neutrinos and the see-saw mechanism

    CERN Document Server

    Choubey, S; Choubey, Sandhya

    2003-01-01

    We show how Lorentz invariance violation (LIV) can occur for Majorana neutrinos, without inducing LIV in the charged leptons via radiative corrections. Such ``electrophobic'' LIV is due to the Majorana nature of the LIV operator together with electric charge conservation. Being free from the strong constraints coming from the charged lepton sector, electrophobic LIV can in principle be as large as current neutrino experiments permit. On the other hand electrophobic LIV could be naturally small if it originates from LIV in some singlet ``right-handed neutrino'' sector, and is felt in the physical left-handed neutrinos via a see-saw mechanism. We develop the formalism appropriate to electrophobic LIV for Majorana neutrinos, and discuss experimental constraints at current and future neutrino experiments.

  6. Prospects of probing $\\theta_{13}$ and neutrino mass hierarchy by Supernova Neutrinos in KamLAND

    CERN Document Server

    Bandyopadhyay, A; Goswami, S; Kar, K; Bandyopadhyay, Abhijit; Choubey, Sandhya; Goswami, Srubabati; Kar, Kamales

    2003-01-01

    In this paper we study the physics potential of the KamLAND detector in probing neutrino oscillation parameters through observation of supernova neutrinos. In particular, we discuss the possibilities of probing the mixing angle $\\theta_{13}$ and determining the sign of $\\Delta m^2_{32}$ from the total charged current(CC) event rates on the proton and $^{12}{C}$ target, as well as from the CC spectra. We discuss the chances of probing the earth matter effect induced modulations from the observation of CC spectra in the different CC reactions in KamLAND and find the volume required to get a statistically significant signature of the earth matter effect in different energy bins. We also calculate the event rates expected in the neutral current (NC) reactions on Carbon and free proton and investigate if the charged current to neutral current ratios, which are free of the absolute luminosity uncertainty in the supernova neutrino fluxes, can be useful in probing the oscillation parameters.

  7. Neutrino mass limits: Robust information from the power spectrum of galaxy surveys

    Science.gov (United States)

    Cuesta, Antonio J.; Niro, Viviana; Verde, Licia

    2016-09-01

    We present cosmological upper limits on the sum of active neutrino masses using large-scale power spectrum data from the WiggleZ Dark Energy Survey and from the Sloan Digital Sky Survey - Data Release 7 (SDSS-DR7) sample of Luminous Red Galaxies (LRG). Combining measurements on the Cosmic Microwave Background temperature and polarisation anisotropies by the Planck satellite together with WiggleZ power spectrum results in a neutrino mass bound of 0.37 eV at 95% C.L., while replacing WiggleZ by the SDSS-DR7 LRG power spectrum, the 95% C.L. bound on the sum of neutrino masses is 0.38 eV. Adding Baryon Acoustic Oscillation (BAO) distance scale measurements, the neutrino mass upper limits greatly improve, since BAO data break degeneracies in parameter space. Within a ΛCDM model, we find an upper limit of 0.13 eV (0.14 eV) at 95% C.L., when using SDSS-DR7 LRG (WiggleZ) together with BAO and Planck. The addition of BAO data makes the neutrino mass upper limit robust, showing only a weak dependence on the power spectrum used. We also quantify the dependence of neutrino mass limit reported here on the CMB lensing information. The tighter upper limit (0.13 eV) obtained with SDSS-DR7 LRG is very close to that recently obtained using Lyman-alpha clustering data, yet uses a completely different probe and redshift range, further supporting the robustness of the constraint. This constraint puts under some pressure the inverted mass hierarchy and favours the normal hierarchy.

  8. Gravitino dark matter and neutrino masses with bilinear R-parity violation

    CERN Document Server

    Restrepo, Diego; Valle, J W F; Zapata, Oscar

    2012-01-01

    Bilinear R-parity violation provides an attractive origin for neutrino masses and mixings. In such schemes the gravitino is a viable decaying dark matter particle whose R-parity violating decays lead to monochromatic photons with rates accessible to astrophysical observations. We determine the parameter region allowed by gamma-ray line searches, dark matter relic abundance and neutrino oscillation data, obtaining a limit on the gravitino mass $m_{\\tilde G} \\lsim$ 1-10 GeV corresponding to a relatively low reheat temperature $T_R \\lsim$ few $\\times 10^7-10^8$ GeV. Neutrino mass and mixing parameters may be reconstructed at accelerator experiments like the Large Hadron Collider.

  9. Cosmological Axion and neutrino mass constraints from Planck 2015 temperature and polarization data

    CERN Document Server

    Di Valentino, Eleonora; Lattanzi, Massimiliano; Mena, Olga; Melchiorri, Alessandro; Silk, Joseph

    2015-01-01

    Axions currently provide the most compelling solution to the strong CP problem. These particles may be copiously produced in the early universe, including via thermal processes. Therefore, relic axions constitute a hot dark matter component and their masses are strongly degenerate with those of the three active neutrinos, as they leave identical signatures in the different cosmological observables. In addition, thermal axions, while still relativistic states, also contribute to the relativistic degrees of freedom, parameterised via $N_{eff}$. We present the cosmological bounds on the relic axion and neutrino masses, exploiting the full Planck mission data, which include polarization measurements. In the mixed hot dark matter scenario explored here, we find the tightest and more robust constraint to date on the sum of the three active neutrino masses, $\\sum m_\

  10. A Model of Radiative Neutrino Mass: with or without Dark Matter

    CERN Document Server

    Ahriche, Amine; Nasri, Salah

    2014-01-01

    We present a three-loop model of neutrino mass whose most-general Lagrangian possesses a softly-broken accidental $Z_2$ symmetry. In the limit that a single parameter vanishes, $\\lambda\\rightarrow0$, the $Z_2$ symmetry becomes exact and the model contains a stable dark-matter candidate. However, even for finite $\\lambda\\ll1$, long-lived dark matter is possible, giving a unified solution to the neutrino mass and dark matter problems that does not invoke a new symmetry. Taken purely as a neutrino mass model, the new physics can be at the TeV scale. When dark matter is incorporated, however, only a singlet scalar can remain this light, though the dark matter can be tested in direct-detection experiments.

  11. Higgs portal dark matter and neutrino mass and mixing with a doubly charged scalar

    CERN Document Server

    Hierro, I M; Rigolin, S

    2016-01-01

    We consider an extension of the Standard Model involving two new scalar particles around the TeV scale: a singlet neutral scalar $\\phi$, to be eventually identified as the Dark Matter candidate, plus a doubly charged $SU(2)_L$ singlet scalar, $S^{++}$, that can be the source for the non-vanishing neutrino masses and mixings. Assuming an unbroken $Z_2$ symmetry in the scalar sector, under which only the additional neutral scalar $\\phi$ is odd, we write the most general (renormalizable) scalar potential. The model may be regarded as a possible extension of the conventional Higgs portal Dark Matter scenario which also accounts for neutrino mass and mixing. This framework cannot completely explain the observed positron excess. However a softening of the discrepancy observed in conventional Higgs portal framework can be obtained, especially when the scale of new physics responsible for generating neutrino masses and lepton number violating processes is around 2 TeV.

  12. Three-loop Neutrino Mass Model with Doubly Charged Particles from Iso-Doublets

    CERN Document Server

    Okada, Hiroshi

    2016-01-01

    We propose a new type of a three-loop induced neutrino mass model with dark matter candidates which are required for the neutrino mass generation. The smallness of neutrino masses can be naturally explained without introducing super heavy particles, namely, much heavier than a TeV scale and quite small couplings as compared to the gauge couplings. We find that as a bonus, the anomaly of the muon anomalous magnetic moment can simultaneously be explained by loop effects of new particles. In our model, there are doubly charged scalar bosons and leptons from isospin doublet fields which give characteristic collider signatures. In particular, the doubly charged scalar bosons can decay into the same sign dilepton with its chirality of both right-handed or left- and right-handed. This can be a smoking gun signature to identify our model and be useful to distinguish other models with doubly charged scalar bosons at collider experiments.

  13. Non-zero $\\theta_{13}$ with Unbroken $\\mu-\\tau$ Symmetry of the Active Neutrino Mass Matrix in the Presence of a Light Sterile Neutrino

    CERN Document Server

    Borah, Debasish

    2016-01-01

    We revisit the possibility of generating non-zero reactor mixing angle in a scenario where there is a sterile neutrino at the eV scale apart from the usual three sub-eV scale active neutrinos. We show that the $3\\times3$ active neutrino mass matrix can possess a $\\mu-\\tau$ symmetry and can still be consistent with non-zero value of the reactor mixing angle $\\theta_{13}$, provided the symmetry is broken in the sterile neutrino sector. We first propose a simple $A_4$ realisation of such a scenario and then numerically evaluate the complete $3+1$ neutrino parameter space that allows such a possibility. We also discuss the possible implications at neutrinoless double beta decay $(0\

  14. Neutrino anomalies without oscillations

    Indian Academy of Sciences (India)

    Sandip Pakvasa

    2000-01-01

    I review explanations for the three neutrino anomalies (solar, atmospheric and LSND) which go beyond the `conventional' neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well.

  15. Systematic errors in the measurement of neutrino masses due to baryonic feedback processes: Prospects for stage IV lensing surveys

    CERN Document Server

    Natarajan, Aravind; Battaglia, Nicholas; Trac, Hy

    2014-01-01

    We examine the importance of baryonic feedback effects on the matter power spectrum on small scales, and the implications for the precise measurement of neutrino masses through gravitational weak lensing. Planned large galaxy surveys such as the Large Synoptic Sky Telescope (LSST) and Euclid are expected to measure the sum of neutrino masses to extremely high precision, sufficient to detect non-zero neutrino masses even in the minimal mass normal hierarchy. We show that weak lensing of galaxies while being a very good probe of neutrino masses, is extremely sensitive to baryonic feedback processes. We use publicly available results from the Overwhelmingly Large Simulations (OWLS) project to investigate the effects of active galactic nuclei feedback, the nature of the stellar initial mass function, and gas cooling rates, on the measured weak lensing shear power spectrum. Using the Fisher matrix formalism and priors from CMB+BAO data, we show that when one does not account for feedback, the measured neutrino mas...

  16. Neutrino 2004: Collection of Presentations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The scientific program covers the latest developments in neutrino physics, astrophysics and related topics through a set of invited talks and 2 poster sessions. The following issues are addressed: - solar neutrinos, - atmospheric neutrinos, - short and long baseline experiments, - neutrino oscillations, - double beta decay, - direct neutrino mass limits, - theory for neutrino masses, neutrino telescopes and ultra-high energy neutrinos, - dark matter searches, - neutrino in astrophysics and cosmology, and - future projects beams and experiments.

  17. Possible Effects of Quantum Mechanics Violation Induced by Certain Quantum Gravity on Neutrino Oscillations

    CERN Document Server

    Chang, C H; Li Xue Qian; Liu, Y; Ma, F C; Tao, Z; CHANG, Chao-Hsi; DAI, Wu-Sheng; LI, Xue-Qian; LIU, Yong; MA, Feng-Cai; TAO, Zhi-jian

    1999-01-01

    In this work we tried extensively to apply the EHNS postulation about the quantum mechanics violation effects induced by the quantum gravity of black holes to neutrino oscillations. The possibilities for observing such effects in the neutrino experiments (in progress and/or accessible in the near future) were discussed. Of them, an interesting one was outlined specially.

  18. Neutrino physics, superbeams and the neutrino factory

    Energy Technology Data Exchange (ETDEWEB)

    Boris Kayser

    2003-10-14

    We summarize what has been learned about the neutrino mass spectrum and neutrino mixing, identify interesting open questions that can be answered by accelerator neutrino facilities of the future, and discuss the importance and physics of answering them.

  19. A model of neutrino mass and dark matter with an accidental symmetry

    Directory of Open Access Journals (Sweden)

    Amine Ahriche

    2015-06-01

    Full Text Available We present a model of radiative neutrino mass that automatically contains an accidental Z2 symmetry and thus provides a stable dark matter candidate. This allows a common framework for the origin of neutrino mass and dark matter without invoking any symmetries beyond those of the Standard Model. The model can be probed by direct-detection experiments and μ→e+γ searches, and predicts a charged scalar that can appear at the TeV scale, within reach of collider experiments.

  20. Neutrino masses and mixing parameters in a left-right model with mirror fermions

    CERN Document Server

    Gaitan, R; Rivera-Rebolledo, J M; de C'ordoba, P F

    2006-01-01

    In this work we consider a left-right model containing mirror fermions with gauge group SU(3)$_{C} \\otimes SU(2)_{L} \\otimes SU(2)_{R} \\otimes U(1)_{Y^\\prime}$. The model has several free parameters which here we have calculated by using the recent values for the squared-neutrino mass differences. Lower bound for the mirror vacuum expectation value helped us to obtain crude estimations for some of these parameters. Also we estimate the order of magnitude of the masses of the standard and mirror neutrinos.

  1. Neutrino Mass Matrices from Two Zero 3x2 Yukawa Textures and Minimal d=5 Entries

    CERN Document Server

    Achelashvili, Avtandil

    2016-01-01

    Aiming to relate leptonic CP violating phase $\\delta$ to the cosmological CP asymmetry, we study the extension of MSSM by two quasi-degenerate (strictly degenerate at tree level) right- handed neutrinos and consider all possible two texture zero 3x2 Yukawa matrices plus one $\\Delta L=2$ dimension five (d=5) operator contributing to the light neutrino mass matrix. We classify all experimentally viable mass matrices, leading to several predictions, and analytically derive predictive relations. We also relate the CP violating $\\delta $ phase to the CP phase of the thermal leptogenesis.

  2. Systematic U(1 ) B - L extensions of loop-induced neutrino mass models with dark matter

    Science.gov (United States)

    Ho, Shu-Yu; Toma, Takashi; Tsumura, Koji

    2016-08-01

    We study the gauged U(1 ) B - L extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by the remnant of the gauge symmetry. Depending on how the lepton number conservation is violated, these models are systematically classified. We present complete lists for the one-loop Z2 and the two-loop Z3 radiative seesaw models as examples of the classification. The anomaly cancellation conditions in these models are also discussed.

  3. External meeting: KATRIN - direct measurement of neutrino masses with sub-eV sensitivity

    CERN Multimedia

    2007-01-01

    GENEVA UNIVERSITY - ECOLE DE PHYSIQUE Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 - Tél : 022 379 62 73 - Fax: 022 379 69 92 Wednesday 18 April 2007 PARTICLE PHYSICS SEMINAR at 17:00 - Stückelberg Auditorium KATRIN - direct measurement of neutrino masses with sub-eV sensitivity by Prof. Guido Drexlin, Karlsruhe Institute of Technology KIT The major scientific objective of the international Karlsruhe Tritum Neutrino (KATRIN) Experiment is the model independent measurement of the electron neutrino mass in tritium beta decay with a sensitivity of 200 meV. In the cosmological context, this allows an investigation of whether massive relic neutrinos left over from the Big Bang play a specific role as hot dark matter in the evolution of large scale structures of the universe. In particle physics KATRIN will allow for discrimination between different neutrino mass models (either of quasi-degenerate or hierarchical pattern).The key components of KATRIN comprise...

  4. Numerical consistency check between two approaches to radiative corrections for neutrino masses and mixings

    Indian Academy of Sciences (India)

    Mrinal Kumar Das; Mahadev Patgiri; N Nimai Singh

    2005-12-01

    We briefly outline the two popular approaches on radiative corrections to neutrino masses and mixing angles, and then carry out a detailed numerical analysis for a consistency check between them in MSSM. We find that the two approaches are nearly consistent with a discrepancy factor of 4.2% with running vacuum expectation value (VEV) (13% for scale-independent VEV) in mass eigenvalues at low-energy scale but the predictions on mixing angles are almost consistent. We check the stability of the three types of neutrino models, i.e., hierarchical, inverted hierarchical and degenerate models, under radiative corrections, using both approaches, and find consistent conclusions. The neutrino mass models which are found to be stable under radiative corrections in MSSM are the normal hierarchical model and the inverted hierarchical model with opposite CP parity. We also carry out numerical analysis on some important conjectures related to radiative corrections in the MSSM, viz., radiative magnification of solar and atmospheric mixings in the case of nearly degenerate model having same CP parity (MPR conjecture) and radiative generation of solar mass scale in exactly two-fold degenerate model with opposite CP parity and non-zero 3 (JM conjecture). We observe certain exceptions to these conjectures. We find a new result that both solar mass scale and 3 can be generated through radiative corrections at low energy scale. Finally the effect of scale-dependent vacuum expectation value in neutrino mass renormalisation is discussed.

  5. The S{sub 3} flavour symmetry: Neutrino masses and mixings

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Canales, F. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico); Facultad de Ciencias de la Electronica, Benemerita Universidad Autonoma de Puebla (Mexico); Mondragon, A.; Mondragon, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico)

    2013-04-02

    In this work, we discuss the neutrino masses and mixings as the realization of an S{sub 3} flavour permutational symmetry in two models, namely the Standard Model and an extension of the Standard Model with three Higgs doublets. In the S{sub 3} Standard Model, mass matrices of the same generic form are obtained for the neutrino and charged leptons when the S{sub 3} flavour symmetry is broken sequentially according to the chain S{sub 3L} x S{sub 3R} contains S{sub 3}{sup diag} contains S{sub 2}. In the minimal S{sub 3}-symmetric extension of the Standard Model, the S{sub 3} symmetry is left unbroken, and the concept of flavour is extended to the Higgs sector by introducing in the theory three Higgs fields which are SU(2) doublets. In both models, the mass matrices of the neutrinos and charged leptons are reparametrized in terms of their eigenvalues, and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained. In the case of the S{sub 3} Standard Model, from a {chi}{sup 2} fit of the theoretical expressions of the lepton mixing matrix to the values extracted from experiment, the numerical values of the neutrino mixing angles are obtained in excellent agreement with experimental data. In the S{sub 3} extension of the Standard Model, if two of the right handed neutrinos masses are degenerate, the reactor and atmospheric mixing angles are determined by the masses of the charged leptons, yielding {theta}{sub 23} in excellent agreement with experimental data, and {theta}{sub 13} different from zero but very small. If the masses of the three right handed neutrinos are assumed to be different, then it is possible to get {theta}{sub 13}also in very good agreement with experimental data. We also show the branching ratios of some selected flavour changing neutral currents (FCNC) process as well as the contribution of the exchange of a neutral flavour changing scalar to the anomaly of the

  6. On the improvement of cosmological neutrino mass bounds

    CERN Document Server

    Giusarma, Elena; Mena, Olga; Vagnozzi, Sunny; Ho, Shirley; Freese, Katherine

    2016-01-01

    The most recent measurements of the temperature and low-multipole polarization anisotropies of the Cosmic Microwave Background (CMB) from the Planck satellite, when combined with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey (BOSS) in the form of the full shape of the power spectrum, and with Baryon Acoustic Oscillation measurements, provide a $95\\%$ confidence level (CL) upper bound on the sum of the three active neutrinos $\\sum m _\

  7. Computation of neutrino masses in R-parity violating supersymmetry: SOFTSUSY3.2

    Science.gov (United States)

    Allanach, B. C.; Kom, C. H.; Hanussek, M.

    2012-03-01

    The program SOFTSUSY can calculate tree-level neutrino masses in the R-parity violating minimal supersymmetric standard model (MSSM) with real couplings. At tree-level, only one neutrino acquires a mass, in contradiction with neutrino oscillation data. Here, we describe an extension to the SOFTSUSY program which includes one-loop R-parity violating effects' contributions to neutrino masses and mixing. Including the one-loop effects refines the radiative electroweak symmetry breaking calculation, and may result in up to three massive, mixed neutrinos. This paper serves as a manual to the neutrino mass prediction mode of the program, detailing the approximations and conventions used. Program summaryProgram title: SOFTSUSY Catalogue identifier: ADPM_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADPM_v3_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 93 291 No. of bytes in distributed program, including test data, etc.: 1 288 618 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on Linux 4.x Word size: 32 bits Classification: 11.1, 11.6 Catalogue identifier of previous version: ADPM_v2_0 Journal reference of previous version: Comput. Phys. Comm. 181 (2010) 232 Does the new version supersede the previous version?: Yes Nature of problem: Calculation of neutrino masses and the neutrino mixing matrix at one-loop level in the R-parity violating minimal supersymmetric standard model. The solution to the renormalisation group equations must be consistent with a high or weak-scale boundary condition on supersymmetry breaking parameters and R-parity violating parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm

  8. KATRIN: an experiment to determine the neutrino mass from the beta decay of tritium

    CERN Document Server

    ,

    2013-01-01

    KATRIN is a very large scale tritium-beta-decay experiment to determine the mass of the neutrino. It is presently under construction at the Karlsruhe Institute of Technology north campus, and makes use of the Karlsruhe Tritium Laboratory built as a prototype for the ITER project. The combination of a large retarding-potential electrostatic-magnetic spectrometer and an intense gaseous molecular tritium source makes possible a sensitivity to neutrino mass of 0.2 eV, about an order of magnitude below present laboratory limits. The measurement is kinematic and independent of whether the neutrino is Dirac or Majorana. The status of the project is summarized briefly in this report.

  9. Neutrino mass hierarchy and {theta}{sub 13} with a magic baseline beta-beam experiment

    Energy Technology Data Exchange (ETDEWEB)

    Agarwalla, Sanjib Kumar [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India) and Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)]. E-mail: sanjib@mri.ernet.in; Choubey, Sandhya [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India)]. E-mail: sandhya@mri.ernet.in; Raychaudhuri, Amitava [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India) and Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)]. E-mail: raychaud@mri.ernet.in

    2007-05-28

    We underscore the physics advantage of an experiment where neutrinos produced in a beta-beam facility at CERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The CERN-INO distance is close to the so-called 'magic' baseline which helps evade some of the parameter degeneracies and allows for a better measurement of the neutrino mass hierarchy and {theta}{sub 13}. We expound the possibility of using radioactive {sup 8}B and {sup 8}Li as the source isotopes for the {nu}{sub e} and {nu}-bar{sub e} beta-beam, respectively, and show that very good sensitivity to both the mass hierarchy and {theta}{sub 13} is possible with a boost {gamma} in the 250-500 ballpark.

  10. Radiative Neutrino Mass Model at the $e^{-}e^{+}$ Linear Collider

    CERN Document Server

    Ahriche, Amine; Soualah, Rachik

    2014-01-01

    We study the phenomenology of a Standard Model (SM) extension with two charged singlet scalars and three right handed (RH) neutrinos at an electron-positron collider. In this model, the neutrino mass is generated radiatively at three-loop, the lightest RH neutrino is a good dark matter candidate; and the electroweak phase transition strongly first order as required for baryogenesis. We focus on the process $e^{+}+e^{-}\\rightarrow e^{-}\\mu^{+}+E_{miss}$, where the model contains new lepton flavor violating interactions that contribute to the missing energy. We investigate the feasibility of detecting this process at future $e^{-}e^{+}$ linear colliders at different center of mass energies: $E_{CM}$=250, 350, 500 GeV and 1 TeV.

  11. Cosmological axion and neutrino mass constraints from Planck 2015 temperature and polarization data

    Directory of Open Access Journals (Sweden)

    Eleonora Di Valentino

    2016-01-01

    Full Text Available Axions currently provide the most compelling solution to the strong CP problem. These particles may be copiously produced in the early universe, including via thermal processes. Therefore, relic axions constitute a hot dark matter component and their masses are strongly degenerate with those of the three active neutrinos, as they leave identical signatures in the different cosmological observables. In addition, thermal axions, while still relativistic states, also contribute to the relativistic degrees of freedom, parameterized via Neff. We present the cosmological bounds on the relic axion and neutrino masses, exploiting the full Planck mission data, which include polarization measurements. In the mixed hot dark matter scenario explored here, we find the tightest and more robust constraint to date on the sum of the three active neutrino masses, ∑mν<0.136 eV at 95% CL, as it is obtained in the very well-known linear perturbation regime. The Planck Sunyaev–Zeldovich cluster number count data further tightens this bound, providing a 95% CL upper limit of ∑mν<0.126 eV in this very same mixed hot dark matter model, a value which is very close to the expectations in the inverted hierarchical neutrino mass scenario. Using this same combination of data sets we find the most stringent bound to date on the thermal axion mass, ma<0.529 eV at 95% CL.

  12. A novel approach to quantifying the sensitivity of current and future cosmological datasets to the neutrino mass ordering through Bayesian hierarchical modeling

    CERN Document Server

    Gerbino, Martina; Mena, Olga; Freese, Katherine

    2016-01-01

    We present a novel approach to derive constraints on neutrino masses from cosmological data, while taking into account our ignorance of the neutrino mass ordering. We derive constraints from a combination of current and future cosmological datasets on the total neutrino mass $M_\

  13. Progenitor-Explosion Connection and Remnant Birth Masses for Neutrino-Driven Supernovae of Iron-Core Progenitors

    CERN Document Server

    Ugliano, Marcella; Marek, Andreas; Arcones, Almudena

    2012-01-01

    We perform hydrodynamic supernova simulations in spherical symmetry for over 100 single stars of solar metallicity to explore the progenitor-explosion and progenitor-remnant connections established by the neutrino-driven mechanism. We use an approximative treatment of neutrino transport and replace the high-density interior of the neutron star (NS) by an inner boundary condition based on an analytic proto-NS core-cooling model, whose free parameters are chosen such that explosion energy, nickel production, and energy release by the compact remnant of progenitors around 20 solar masses are compatible with Supernova 1987A. Thus we are able to simulate the accretion phase, initiation of the explosion, subsequent neutrino-driven wind phase for 15-20 s, and the further evolution of the blast wave for hours to days until fallback is completed. Our results challenge long-standing paradigms. We find that remnant mass, launch time, and properties of the explosion depend strongly on the stellar structure and exhibit la...

  14. Neutrino Mass, Dark Matter and Anomalous Magnetic Moment of Muon in a $U(1)_{L_{\\mu}-L_{\\tau}}$ Model

    CERN Document Server

    Biswas, Anirban; Khan, Sarif

    2016-01-01

    The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free and can explain the beyond SM measurement of the anomalous muon $({\\rm g-2})$ through additional contribution arising from the extra $Z_{\\mu\\tau}$ mediated diagram. Small neutrino masses are explained naturally through the Type-I seesaw mechanism, while the mixing angles are predicted to be in their observed ranges due to the broken $L_\\mu-L_\\tau$ symmetry. The second complex scalar is shown to be stable and becomes the dark matter candidate in our model. We show that while the $Z_{\\mu\\tau}$ portal is ineffective for the...

  15. Identifying neutrino mass hierarchy at extremely small theta13 through earth matter effects in a supernova signal.

    Science.gov (United States)

    Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro

    2008-10-24

    Collective neutrino flavor transformations deep inside a supernova are sensitive to the neutrino mass hierarchy even at extremely small values of theta_(13). Exploiting this effect, we show that comparison of the antineutrino signals from a galactic supernova in two megaton class water Cherenkov detectors, one of which is shadowed by Earth, will enable us to distinguish between the hierarchies if sin(2)theta_(13) < or approximately 10(-5), where long baseline neutrino experiments would be ineffectual.

  16. Search for new candidates for the neutrino-oriented mass determination by electron-capture

    CERN Multimedia

    Herfurth, F; Boehm, C; Blaum, K; Beck, D

    2008-01-01

    This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

  17. Project 8: Determining neutrino mass from tritium beta decay using a frequency-based method

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Peter J.; Kofron, Jared N.; MCBride, Lisa; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Doelman, S.; Rogers, Alan E.; Formaggio, Joseph; Furse, Daniel; Oblath, Noah S.; LaRoque, Benjamin; Leber, Michelle; Monreal, Ben; Bahr, Matthew; Asner, David M.; Jones, Anthony M.; Fernandes, Justin L.; VanDevender, Brent A.; Patterson, Ryan B.; Bradley, Rich; Thummler, Thomas

    2013-10-04

    A general description is given of Project 8, a new approach to measuring the neutrino mass scale via the beta decay of tritium. In Project 8, the energy of electrons emitted in beta decay is determined from the frequency of cyclotron radiation emitted as the electrons spiral in a uniform magnetic field

  18. Forecasts on neutrino mass constraints from the redshift-space two-point correlation function

    Science.gov (United States)

    Petracca, F.; Marulli, F.; Moscardini, L.; Cimatti, A.; Carbone, C.; Angulo, R. E.

    2016-11-01

    We provide constraints on the accuracy with which the neutrino mass fraction, fν, can be estimated when exploiting measurements of redshift-space distortions, describing in particular how the error on neutrino mass depends on three fundamental parameters of a characteristic galaxy redshift survey: density, halo bias and volume. In doing this, we make use of a series of dark matter halo catalogues extracted from the BASICC simulation. The mock data are analysed via a Markov Chain Monte Carlo likelihood analysis. We find a fitting function that well describes the dependence of the error on bias, density and volume, showing a decrease in the error as the bias and volume increase, and a decrease with density down to an almost constant value for high-density values. This fitting formula allows us to produce forecasts on the precision achievable with future surveys on measurements of the neutrino mass fraction. For example, a Euclid-like spectroscopic survey should be able to measure the neutrino mass fraction with an accuracy of δfν ≈ 3.1 × 10-3 (which is equivalent to δ∑mν ≈ 0.039eV), using redshift-space clustering once all the other cosmological parameters are kept fixed to the ΛCDM case.

  19. Project 8: Determining neutrino mass from tritium beta decay using a frequency-based method

    CERN Document Server

    Doe, P J; McBride, E L; Robertson, R G H; Rosenberg, L J; Rybka, G; Doelman, S; Rogers, A; Formaggio, J A; Furse, D; Oblath, N S; LaRoque, B H; Leber, M; Monreal, B; Bahr, M; Asner, D M; Jones, A M; Fernandes, J; VanDevender, B A; Patterson, R; Bradley, R; Thuemmler, T

    2013-01-01

    A general description is given of Project 8, a new approach to measuring the neutrino mass scale via the beta decay of tritium. In Project 8, the energy of electrons emitted in beta decay is determined from the frequency of cyclotron radiation emitted as the electrons spiral in a uniform magnetic field.

  20. The revival of two old ways to measure the electron-neutrino mass

    CERN Document Server

    CERN. Geneva

    2013-01-01

    Meanwhile, the Tritium-decay neutrino-mass limits have improved by a factor of 15, and the difficulty of the experiments by the cube of that figure. Can the "calorimetric" EC theory cope with this increased challenge? I shall answer this question affirmatively. I shall also broach the ongoing beta-decay and EC experiments and report on progress i...

  1. Determination of the neutrino mass hierarchy in the regime of small matter effect

    CERN Document Server

    Schwetz, T

    2007-01-01

    We point out a synergy between T-conjugated oscillation channels in the determination of the neutrino mass hierarchy with oscillation experiments with relatively short baselines (L < 700 km), where the matter effect is small. If information from all four oscillation channels $\

  2. Sterile neutrinos with eV masses in cosmology — How disfavoured exactly?

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, G.G.

    2011-01-01

    We study cosmological models that contain sterile neutrinos with eV-range masses as suggested by reactor and short-baseline oscillation data. We confront these models with both precision cosmological data (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch). In ...

  3. Neutrino masses and mixing: a flavour symmetry roadmap

    CERN Document Server

    Morisi, S

    2012-01-01

    Over the last ten years tri-bimaximal mixing has played an important role in modeling the flavour problem. We give a short review of the status of flavour symmetry models of neutrino mixing. We concentrate on non-Abelian discrete symmetries, which provide a simple way to account for the TBM pattern. We discuss phenomenological implications such as neutrinoless double beta decay, lepton flavour violation as well as theoretical aspects such as the possibility to explain quarks and leptons within a common framework, such as grand unified models.

  4. The nucleon axial mass and the MiniBooNE quasielastic neutrino-nucleus scattering problem

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, J., E-mail: jmnieves@ific.uv.es [Instituto de Fisica Corpuscular (IFIC), Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, E-46071 Valencia (Spain); Ruiz Simo, I.; Vicente Vacas, M.J. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, E-46071 Valencia (Spain)

    2012-01-16

    The charged-current double differential neutrino cross section, measured by the MiniBooNE Collaboration, has been analyzed using a microscopical model that accounts for, among other nuclear effects, long range nuclear (RPA) correlations and multinucleon scattering. We find that MiniBooNE data are fully compatible with the world average of the nucleon axial mass in contrast with several previous analyses which have suggested an anomalously large value. We also discuss the reliability of the algorithm used to estimate the neutrino energy.

  5. The nucleon axial mass and the MiniBooNE Quasielastic Neutrino-Nucleus Scattering problem

    CERN Document Server

    Nieves, J; Vacas, M J Vicente

    2011-01-01

    The charged-current double differential neutrino cross section, measured by the MiniBooNE Collaboration, has been analyzed using a microscopical model that accounts for, among other nuclear effects, long range nuclear (RPA) correlations and multinucleon scattering. We find that MiniBooNE data are fully compatible with the world average of the nucleon axial mass in contrast with several previous analyses which have suggested an anomalously large value. We also discuss the reliability of the algorithm used to estimate the neutrino energy.

  6. Constraints on neutrino masses from the lensing dispersion of Type Ia supernovae

    CERN Document Server

    Hada, Ryuichiro

    2016-01-01

    We investigate how accurately the total mass of neutrinos is constrained from the magnitude dispersion of Type Ia supernovae due to the effects of gravitational lensing. For this purpose, we use the propagation equation of light bundles in a realistic inhomogeneous universe and propose a sample selection for supernovae to avoid difficulties associated with small scale effects such as strong lensing or shear effects. With a fitting formula for the non-linear matter power spectrum taking account of the effects of massive neutrino, we find that in our model it is possible to obtain the upper limit $\\Sigma m_{\

  7. Mass Hierarchy Resolution in Reactor Anti-neutrino Experiments: Parameter Degeneracies and Detector Energy Response

    Energy Technology Data Exchange (ETDEWEB)

    X. Qian, D. A. Dwyer, R. D. McKeown, P. Vogel, W. Wang, C. Zhang`

    2013-02-01

    Determination of the neutrino mass hierarchy using a reactor neutrino experiment at ∼60  km is analyzed. Such a measurement is challenging due to the finite detector resolution, the absolute energy scale calibration, and the degeneracies caused by current experimental uncertainty of |Δm{sub 32}{sup 2}|. The standard {chi}{sup 2} method is compared with a proposed Fourier transformation method. In addition, we show that for such a measurement to succeed, one must understand the nonlinearity of the detector energy scale at the level of a few tenths of percent.

  8. Right-handed sneutrinos as asymmetric DM and neutrino masses from neutrinophilic Higgs bosons

    CERN Document Server

    Mitropoulos, Pantelis

    2013-01-01

    We consider an extension of the Next-to-Minimal Supersymmetric Standard Model by three right-handed neutrinos and a pair of neutrinophilic Higgs superfields. The small neutrino masses arise naturally from a small vacuum expectation value of the additional Higgs fields (hence without lepton number violation), while the lightest right-handed sneutrinos can constitute asymmetric Dark Matter. The right-handed sneutrino and baryon asymmetries are connected through equilibrium processes in the early universe, explaining the coincidence of the DM and baryon abundances. We show that particle physics and astrophysical constraints are satisfied.

  9. Neutrino oscillations, seesaw mechanism and the quest for new physics

    CERN Document Server

    Miranda, O G

    2016-01-01

    The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, have brought neutrino physics to the precision era. Apart from dedicated leptonic CP violation studies, upcoming experiments should probe the unitarity of the lepton mixing matrix. These will shed light on the scale of new physics, such as the seesaw scale, and thereby guide us towards what could be the next step in particle physics. Moreover these efforts may also bring the key to elucidate some of the current cosmological puzzles.

  10. Neutrino Mass Ordering Studies with PINGU and IceCube/DeepCore

    CERN Document Server

    Wren, Steven

    2016-01-01

    The Precision IceCube Next Generation Upgrade (PINGU) is a proposed extension to the IceCube detector. The design of PINGU would augment the existing 86 strings with an additional 40 with the main goal of determining the neutrino mass ordering (NMO). Preliminary studies of the NMO can start with IceCube/DeepCore, a sub-array of more densely- packed strings in operation since 2011. This detector has a neutrino energy threshold of roughly 10 GeV and allows for high-statistics datasets of atmospheric neutrinos to be collected. This data provides a unique opportunity to better understand the systematic effects involved in making the NMO measurement by comparing the simulation studies to real data. These proceedings will present the current status of these studies in Monte Carlo simulations with projected DeepCore sensitivity for the NMO.

  11. Neutrino mass effects on vector and tensor CMB anisotropies in the presence of a primordial magnetic field

    CERN Document Server

    Kojima, Kazuhiko; Yamazaki, Dai G; Kajino, Toshitaka; Mathews, Grant J

    2008-01-01

    If a primordial magnetic field (PMF) is present during photon decoupling and afterward, a finite neutrino mass can affect all modes of the CMB. In this work, we expand on earlier studies of the scalar mode effects by constructing the vector and tensor mode equations in the presence of massive neutrinos and a PMF. We compute the power spectrum of the various modes in an illustrative example and find that the neutrino mass can significantly affect the vector and tensor modes when a PMF exists, while the effects are negligible for no PMF. The most prominent result of the present analysis is the behavior of the EE component of the tensor mode at low multipoles. For massive neutrinos the EE mode can become comparable to the observed primary anisotropy. Therefore, if and when the EE mode power spectrum is measured at low multipoles the possibility exists to place a strong constraint on the sum of the neutrino masses.

  12. Spontaneous R-parity breaking, stop LSP decays and the neutrino mass hierarchy

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Zachary, E-mail: zlmarshall@lbl.gov [Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94704 (United States); Ovrut, Burt A., E-mail: ovrut@elcapitan.hep.upenn.edu [Department of Physics, University of Pennsylvania, Philadelphia, PA 19104-6396 (United States); Purves, Austin, E-mail: apurves@sas.upenn.edu [Department of Physics, University of Pennsylvania, Philadelphia, PA 19104-6396 (United States); Spinner, Sogee, E-mail: sogee@sas.upenn.edu [Department of Physics, University of Pennsylvania, Philadelphia, PA 19104-6396 (United States)

    2014-05-01

    The MSSM with right-handed neutrino supermultiplets, gauged B−L symmetry and a non-vanishing sneutrino expectation value is the minimal theory that spontaneously breaks R-parity and is consistent with the bounds on proton stability and lepton number violation. This minimal B−L MSSM can have a colored/charged LSP, of which a stop LSP is the most amenable to observation at the LHC. We study the R-parity violating decays of a stop LSP into a bottom quark and charged leptons – the dominant modes for a generic “admixture” stop. A numerical analysis of the relative branching ratios of these decay channels is given using a wide scan over the parameter space. The fact that R-parity is violated in this theory by a vacuum expectation value of a sneutrino links these branching ratios directly to the neutrino mass hierarchy. It is shown how a discovery of bottom-charged lepton events at the LHC can potentially determine whether the neutrino masses are in a normal or inverted hierarchy, as well as determining the θ{sub 23} neutrino mixing angle. Finally, present LHC bounds on these leptoquark signatures are used to put lower bounds on the stop mass.

  13. Neutrinos and the matter-antimatter asymmetry in the Universe

    CERN Document Server

    Felipe, R Gonzalez

    2011-01-01

    The discovery of neutrino oscillations provides a solid evidence for nonzero neutrino masses and leptonic mixing. The fact that neutrino masses are so tiny constitutes a puzzling problem in particle physics. From the theoretical viewpoint, the smallness of neutrino masses can be elegantly explained through the seesaw mechanism. Another challenging issue for particle physics and cosmology is the explanation of the matter-antimatter asymmetry observed in Nature. Among the viable mechanisms, leptogenesis is a simple and well-motivated framework. In this talk we briefly review these aspects, making emphasis on the possibility of linking neutrino physics to the cosmological baryon asymmetry originated from leptogenesis.

  14. A natural connection between neutrino mass generation and the lightness of a next-to-minimal supersymmetric Standard Model pseudoscalar

    Indian Academy of Sciences (India)

    Debottam Das; Asmaa Abada; Gautam Bhattacharyya; Cédric Weiland

    2012-10-01

    One of the attractive properties of the NMSSM is that it can accommodate a light pseudoscalar of order 10 GeV. However, such scenarios are constrained by several experimental results, especially those related to the fermionic decays of the pseudoscalar. In this work, extending the NMSSM field content by two gauge singlets, with lepton number +1 and −1, we generate neutrino masses via the inverse see-saw mechanism at one hand and on the other hand a very light pseudoscalar becomes experimentally viable by having dominant invisible decay channels which help it to evade the existing bounds.

  15. Search for narrow. mu. (. pi. ( mass enhancements in a neutrino bubble-chamber experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ballagh, H.C.; Bingham, H.H.; Lawry, T.J.; Lynch, G.R.; Lys, J.; Stevenson, M.L.; Huson, F.R.; Schmidt, E.; Smart, W.; Sokoloff, M.D.

    1984-04-01

    In a Fermilab 15-foot bubble-chamber experiment, ..mu../sup - +/..pi../sup + -/ mass spectra were studied in 8444 neutrino interactions and 1367 antineutrino interactions. No significant narrow mass enhancements were found. A peak near 430 MeV/c/sup 2/ was observed, but when resolution is taken into account its significance is only roughly-equal1sigma and its angular distributions do not show the characteristics expected for a resonance.

  16. Sterile Neutrinos and Flavor Ratios in IceCube

    CERN Document Server

    Brdar, Vedran; Wang, Xiao-Ping

    2016-01-01

    The flavor composition of astrophysical neutrinos observed in neutrino telescopes is a powerful discriminator between different astrophysical neutrino production mechanisms and can also teach us about the particle physics properties of neutrinos. In this paper, we investigate how the possible existence of light sterile neutrinos can affect these flavor ratios. We consider two scenarios: (i) neutrino production in conventional astrophysical sources, followed by partial oscillation into sterile states; (ii) neutrinos from dark matter decay with a primary flavor composition enhanced in tau neutrinos or sterile neutrinos. Throughout the paper, we constrain the sterile neutrino mixing parameters from a full global fit to short and long baseline data. We present our results in the form of flavor triangles and, for scenario (ii), as exclusion limits on the dark matter mass and lifetime, derived from a fit to IceCube high energy starting events and through-going muons. We argue that identifying a possible flux of neu...

  17. Fermion masses and mixings in the 3-3-1 model with right-handed neutrinos based on the S{sub 3} flavor symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.E.C. [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Martinez, R.; Ochoa, F. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia)

    2016-11-15

    We propose a 3-3-1 model where the SU(3){sub C} x SU(3){sub L} x U(1){sub X} symmetry is extended by S{sub 3} x Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} and the scalar spectrum is enlarged by extra SU(3){sub L} singlet scalar fields. The model successfully describes the observed SM fermion mass and mixing pattern. In this framework, the light active neutrino masses arise via an inverse seesaw mechanism and the observed charged fermion mass and quark mixing hierarchy is a consequence of the Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} symmetry breaking at very high energy. The obtained physical observables for both quark and lepton sectors are compatible with their experimental values. The model predicts the effective Majorana neutrino mass parameter of neutrinoless double beta decay to be m{sub ββ} = 4 and 48 meV for the normal and the inverted neutrino spectra, respectively. Furthermore, we found a leptonic Dirac CP-violating phase close to (π)/(2) and a Jarlskog invariant close to about 3 x 10{sup -2} for both normal and inverted neutrino mass hierarchy. (orig.)

  18. 利用超新星爆发测量电子中微子静止质量%MEASUREMENT OF ELECTRON NEUTRINO MASS BY SUPERNOVA NEUTRINO BURSTS

    Institute of Scientific and Technical Information of China (English)

    戴长江; 盛祥东; 何会林

    2000-01-01

    The status of neutrino mass measurements is revie wed, with particular mention of measurements of the supernova 1987A neutrino bu rsts. From the data analyses of Kamiokande, IMB and Bakson the upper limit of th e electron neutrino mass is found to be less than 14 eV (95% C.L.). A descriptio n is given of the new solar neutrino spectrometer to be built which will detect solar neutrinos as well as measure the mass of supernova neutrinos. The possibil ity of detection of a neutrino mass<1 eV is also discussed.%综述了中微子静止质量mνe的测 量方法与结果,侧重介绍了超新星SN87A中微子测量的结果,即得到具有能量为8MeV和36MeV 的 中微子飞行时间差,对于Kamiokande, IMB, Bakson分别为1.9s,6s和9s,由此给出电 子中微子静止质量上限为14eV[95%置信水平(C.L.)].并且描述了计划建造的新型太阳中 微子能谱仪,该谱仪在观测太阳中微子能谱的同时,将兼测超新星中微子,提供了在m νe<1eV范围内测量中微子静止质量的可能性.

  19. Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors

    CERN Document Server

    Wang, Hongxin; Li, Yu-Feng; Cao, Guofu; Chen, Shenjian

    2016-01-01

    We report the neutrino mass hierarchy (MH) sensitivity of medium baseline reactor neutrino experiments with multiple detectors. Sensitivity of determining the MH can be significantly improved by adding a near detector and combining both the near and far detectors. The size of the sensitivity improvement is related to accuracy of the individual mass-splitting measurements and requires strict control on the relative energy scale uncertainty of the near and far detectors. We study the impact of both baseline and target mass of the near detector on the combined sensitivity. A figure-of-merit is defined to optimize the baseline and target mass of the near detector and the optimal selections are $\\sim$13~km and $\\sim$4~kton respectively for a far detector with the 20~kton target mass and 52.5~km baseline. As typical examples of future medium baseline reactor neutrino experiments, the optimal location and target mass of the near detector are selected for JUNO and RENO-50. Finally, we discuss distinct effects of the ...

  20. Neutrino mixing and masses in SO(10) GUTs with hidden sector and flavor symmetries

    CERN Document Server

    Chu, Xiaoyong

    2016-01-01

    We consider the neutrino masses and mixing in the framework of SO(10) GUTs with hidden sector consisting of fermionic and bosonic SO(10) singlets and flavor symmetries. The framework allows to disentangle the CKM physics responsible for the CKM mixing and different mass hierarchies of quarks and leptons and the neutrino new physics which produces smallness of neutrino masses and large lepton mixing. The framework leads naturally to the relation $U_{PMNS} \\sim V_{CKM}^{\\dagger} U_0$, where structure of $U_0$ is determined by the flavor symmetry. The key feature of the framework is that apart from the Dirac mass matrices $m_D$, the portal mass matrix $M_D$ and the mass matrix of singlets $M_S$ are also involved in generation of the lepton mixing. This opens up new possibilities to realize the flavor symmetries and explain the data. Using $A_4 \\times Z_4$ as the flavor group, we systematically explore the flavor structures which can be obtained in this framework depending on field content and symmetry assignment...