WorldWideScience

Sample records for active-unsterile neutrino mixing

  1. Democratic Neutrino Mixing Reexamined

    CERN Document Server

    Fritzsch, Harald; Fritzsch, Harald; Xing, Zhi-zhong

    2004-01-01

    We reexamine the democratic neutrino mixing ansatz, in which the mass matrices of charged leptons and Majorana neutrinos arise respectively from the explicit breaking of S(3)_L x S(3)_R and S(3) flavor symmetries. It is shown that a democracy term in the neutrino sector can naturally allow the ansatz to fit the solar neutrino mixing angle \\theta_sun \\approx 33^\\circ. We predict \\sin^2 2\\theta_atm \\approx 0.95 for atmospheric neutrino mixing and J \\approx 1.2% for leptonic CP violation in neutrino oscillations without any fine-tuning. Direct relations between the model parameters and experimental observables are also discussed.

  2. 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.

  3. Neutrino Mixing: Theoretical Overview

    CERN Document Server

    Altarelli, Guido

    2013-01-01

    We present a concise review of the recent important experimental developments on neutrino mixing (hints for sterile neutrinos, large $\\theta_{13}$, possible non maximal $\\theta_{23}$, approaching sensitivity on $\\delta_{CP}$) and their implications on models of neutrino mixing. The new data disfavour many models but the surviving ones still span a wide range going from Anarchy (no structure, no symmetry in the lepton sector) to a maximum of symmetry, as for the models based on discrete non-abelian flavour groups that can be improved following the indications from the data.

  4. Modulated bimaximal neutrino mixing

    CERN Document Server

    Roy, Subhankar

    2016-01-01

    The present article is an endeavor to look into some fruitful frameworks based on "Bi-maximal" neutrino mixing, from a model independent stand. The possibilities involving the correction or attenuation of the original BM mixing matrix, followed by GUT-inspired charged lepton correction are invoked. The "symmetry-basis" thus constructed, accentuates some interesting facets such as: a modified QLC relation, $\\theta_{12}+\\theta_{c}\\approx\\frac{\\pi}{4}-\\theta_{13}\\cos(n\\pi-\\delta_{CP})$, a possible link up between neutrino and charged lepton sectors, $\\theta_{13}^{\

  5. 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.

  6. An Overview of Neutrino Mixing

    CERN Document Server

    Altarelli, G

    2013-01-01

    We present a concise review of the recent important experimental developments on neutrino mixing (hints for sterile neutrinos, large $\\theta_{13}$, possible non maximal $\\theta_{23}$, approaching sensitivity on $\\delta_{CP}$) and their implications on models of neutrino mixing. The new data disfavour many models but the surviving ones still span a wide range going from Anarchy (no structure, no symmetry in the lepton sector) to a maximum of symmetry, as for the models based on discrete non-abelian flavour groups.

  7. The Mystery of Neutrino Mixings

    CERN Document Server

    Altarelli, Guido

    2011-01-01

    In the last years we have learnt a lot about neutrino masses and mixings. Neutrinos are not all massless but their masses are very small. Probably masses are small because neutrinos are Majorana particles with masses inversely proportional to the large scale M of lepton number (L) violation, which turns out to be compatible with the GUT scale. We have understood that there is no contradiction between large neutrino mixings and small quark mixings, even in the context of GUTs and that neutrino masses fit well in the SUSY GUT picture. Out of equilibrium decays with CP and L violation of heavy RH neutrinos can produce a B-L asymmetry, then converted near the weak scale by instantons into an amount of B asymmetry compatible with observations (baryogenesis via leptogenesis). It appears that active neutrinos are not a significant component of Dark Matter in the Universe. A long list of models have been formulated over the years to understand neutrino masses and mixings. With the continuous improvement of the data m...

  8. 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 $\

  9. 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.

  10. 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_{\

  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. Neutrino oscillations and the maximal mixing scenario

    International Nuclear Information System (INIS)

    The problem of neutrino oscillation is considered in the plane wave formalism, as well as in the full wave packet quantum mechanics language. It is shown that Lorentz invariance implies that in general, flavour neutrinos in oscillation experiments are superpositions of massive neutrinos with different energies and different momenta. The hypothesis of threefold-maximal neutrino mixing is investigated and the implications on the coherence of the states is analysed. (authors)

  13. Next discoveries in neutrino mixing: Electron neutrino appearance

    Science.gov (United States)

    Duyang, Hongyue

    The discovery of neutrino oscillation is a clear evidence of new physics beyond the Standard Model. Measurements of electron neutrino (nu e) and electron anti-neutrino (nu e) appearances are the most important channels to complete the neutrino mixing matrix. In a nue/ nue appearance experiment, a near detector (ND) is used to constrain the neutrino flux and measure the backgrounds to the signal. Backgrounds to the nue appearance comes from Neutral Current Muon Neutrino Interactions (numu-NC), Charged Current Muon Neutrino Interactions (numu-CC), beam nu e events and outside backgrounds. The background components are then extrapolated to the far detector (FD). By looking for excess of signal nu e/nue-like events in FD, we measure the neutrino mixing angle, neutrino's mass hierarchy and the elusive CP-violation in the lepton sector. This dissertation focuses on the signals and backgrounds in nu e/nue appearance measurements. The first part of the dissertation presents an analysis of nue appearance in a large Water Cherenkov detector such as the one proposed by the LBNE collaboration. The analysis, including scanning thousands of events, aims to distinguish nu e signals from the NC backgrounds. The second part of the dissertation presents measurements of Resonance Neutrino Interactions using the NOMAD data. This process plays a critical role in not only neutrino-nuclear cross section but also in the precision analysis of the next generation of neutrino oscillation experiments such as NOnuA and LBNE. The last part of the dissertation discusses the method of using low-nu fit method to measure relative neutrino flux and constrain beam nue background.

  14. Neutrino Oscillations and Lepton Flavor Mixing

    CERN Document Server

    Kang, K; Kim, C S; Kim, S M; Kang, Kyungsik; Kang, Sin Kyu; Kim, Sun Myoung

    1998-01-01

    In view of the recent announcement on non-zero neutrino mass from Super-Kamiokande experiment, it would be very timely to investigate all the possible scenarios on masses and mixings of light neutrinos. Recently suggested mass matrix texture for the quark CKM mixing, which can be originated from the family permutation symmetry and its suitable breakings, is assumed for the neutrino mass matrix and determined by the four combinations of solar, atmospheric and LSND neutrino data and cosmological hot dark matter bound as input constraints. The charged-lepton mass matrix is assumed to be diagonal so that the neutrino mixing matrix can be identified directly as the lepton flavor mixing matrix and no CP invariance violation originates from the leptonic sector. The results favor hierarchical patterns for the neutrino masses, which follow from the case when either solar-atmospheric data or solar-HDM constraints are used.

  15. Twisted flavors and tribimaximal neutrino mixing.

    Science.gov (United States)

    Haba, Naoyuki; Watanabe, Atsushi; Yoshioka, Koichi

    2006-07-28

    A new framework for handling flavor symmetry breaking in the neutrino sector is discussed where the source of symmetry breaking is traced to the global property of right-handed neutrinos in extra-dimensional space. Light neutrino phenomenology has rich and robust predictions such as the tribimaximal form of generation mixing, controlled mass spectrum, and no need of flavor mixing couplings in the theory.

  16. Massive neutrinos flavor mixing of leptons and neutrino oscillations

    CERN Document Server

    2015-01-01

    Since the discovery of neutrino oscillations neutrino physics has become an interesting field of research in physics. They imply that neutrino must have a small mass and that the neutrinos, coupled to the charged leptons, are mixtures of the mass eigenstates, analogous to the flavor mixing of the quarks. The mixing angles for the quarks are small, but for the leptons two of the mixing angles are large. The masses of the three neutrinos must be very small, less than 1 eV, but from the oscillation experiments we only know the mass differences — the absolute masses are still unknown. Also we do not know, if the masses of the neutrinos are Dirac masses, as the masses of the charged leptons and of the quarks, or whether they are Majorana masses. In this volume, an overview of the present state of research in neutrino physics is given by well-known experimentalists and theorists. The contents — originated from talks and discussions at a recent conference addressing some of the most pressing open questions in n...

  17. Constraints on three flavor neutrino mixing

    Indian Academy of Sciences (India)

    Mohan Narayan

    2000-01-01

    We summarize the constraints on three flavor neutrino mixing coming from data. We first map out the allowed region in the three neutrino parameter space using solar and atmospheric neutrino data. We then incorporate the results of reactor and long baseline experiments in our analysis and show that the parameter space is drastically reduced. We conclude by pointing out that the results of Borexino and SNO will further help in constraining the parameter space.

  18. Composite model with large mixing of neutrinos

    CERN Document Server

    Haba, N

    1999-01-01

    We suggest a simple composite model that induces the large flavor mixing of neutrino in the supersymmetric theory. This model has only one hyper-color in addition to the standard gauge group, which makes composite states of preons. In this model, {\\bf 10} and {\\bf 1} representations in SU(5) grand unified theory are composite states and produce the mass hierarchy. This explains why the large mixing is realized in the lepton sector, while the small mixing is realized in the quark sector. This model can naturally solve the atmospheric neutrino problem. We can also solve the solar neutrino problem by improving the model.

  19. Dark energy, cosmological constant and neutrino mixing

    OpenAIRE

    A. Capolupo; Capozziello, S.; Vitiello, G.

    2007-01-01

    The today estimated value of dark energy can be achieved by the vacuum condensate induced by neutrino mixing phenomenon. Such a tiny value is recovered for a cut-off of the order of Planck scale and it is linked to the sub eV neutrino mass scale. Contributions to dark energy from auxiliary fields or mechanisms are not necessary in this approach.

  20. 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.

  1. Deviations in Tribimaximal Mixing From Sterile Neutrino Sector

    CERN Document Server

    Dev, S; Gautam, Radha Raman

    2016-01-01

    We explore the possibility of generating a non-zero $U_{e3}$ element of the neutrino mixing matrix from tribimaximal neutrino mixing by adding a light sterile neutrino to the active neutrinos. Small active-sterile mixing can provide the necessary deviation from tribimaximal mixing to generate a non-zero $\\theta_{13}$ and atmospheric mixing $\\theta_{23}$ different from maximal. Assuming no CP-violation, we study the phenomenological impact of sterile neutrinos in the context of current neutrino oscillation data. The tribimaximal pattern is broken in such a manner that the second column of tribimaximal mixing remains intact in the neutrino mixing matrix.

  2. Large Solar Neutrino Mixing and Radiative Neutrino Mechanism

    CERN Document Server

    Kitabayashi, T; Kitabayashi, Teruyuki; Yasue, Masaki

    2002-01-01

    We find that the presence of a global $L_e-L_\\mu-L_\\tau$ ($\\equiv L^\\prime$) symmetry and an $S_2$ permutation symmetry for the $\\mu$- and $\\tau$-families supplemented by a discrete $Z_4$ symmetry naturally leads to almost maximal atmospheric neutrino mixing and large solar neutrino mixing, which arise, respectively, from type II seesaw mechanism initiated by an $S_2$-symmetric triplet Higgs scalar $s$ with $L^\\prime=2$ and from radiative mechanism of the Zee type initiated by two singly charged scalars, an $S_2$-symmetric $h^+$ with $L^\\prime=0$ and an $S_2$-antisymmetric $h^{\\prime +}$ with $L^\\prime=2$. The almost maximal mixing for atmospheric neutrinos is explained by the appearance of the democratic coupling of $s$ to neutrinos ensured by $S_2$ and $Z_4$ while the large mixing for solar neutrinos is explained by the similarity of $h^+$- and $h^{\\prime +}$-couplings described by $f^h_+\\sim f^h_-$ and $\\mu_+\\sim\\mu_-$, where $f^h_+$ ($f^h_-$) and $\\mu_+$ ($\\mu_-$) stand for $h^+$ ($h^{\\prime +}$)-coupling...

  3. Three-neutrino mixing: status and prospects

    Science.gov (United States)

    Marrone, A.; Capozzi, F.; Lisi, E.; Montanino, D.; Palazzo, A.

    2016-05-01

    We discuss the present knowledge of the neutrino oscillation parameters. In a three-neutrino scenario, neutrino oscillations depend on six parameters, two squared mass differences (Δm2, δm2), three mixing angles (θ 12, θ13 , θ 23) and one phase δ. While five out of these six parameters have been measured, the CP-violating phase δ remains unknown. Moreover, the octant of the mixing angle θ23 and the neutrino mass hierarchy are still undetermined. We update our previous analysis, by adding to the global fit the recent results of the antineutrino running of T2K, the first results of the NOvA experiment, the latest SuperKamiokande and IceCube atmospheric neutrino data.

  4. Large Neutrino Mixing from Renormalization Group Evolution

    CERN Document Server

    Balaji, K R S; Parida, M K; Paschos, E A

    2001-01-01

    The renormalization group evolution equation for two neutrino mixing is known to exhibit nontrivial fixed point structure corresponding to maximal mixing at the weak scale. The presence of the fixed point provides a natural explanation of the observed maximal mixing of $\

  5. Parameterization for Neutrino Mixing Matrix with Deviated Unitarity

    Institute of Scientific and Technical Information of China (English)

    LU Lei; WANG Wen-Yu; XIONG Zhao-Hua

    2009-01-01

    Neutrino oscillation experiments provide the first evidence on non-zero neutrino masses and indicate new physics beyond the standard model.With Majorana neutrinos introduced to acquire tiny neutrino maases,it leads to the existence of more than three neutrino species,implying that the ordinary neutrino mixing matrix is only a part of the whole extended unitary mixing matrix and thus no longer unitary.We give a parameterization for a non-unitary neutrino mixing matrix under seesaw framework and further present a method to test the unitarity of the ordinary neutrino mixing matrix.

  6. The solar neutrino problem: Mixing of neutrinos and mixing in the sun

    Science.gov (United States)

    Haxton, W. C.

    I review the current status of the solar neutrino problem, including the exciting possibility of matter enhanced neutrino oscillations. Neutrino flux measurements, independent of questions of solar dynamics, appear to leave only one competing candidate astrophysical solution, at least in the case of steady-state solar models. That possibility - mixing of the solar core on time scales of 3He equilibration - appears to have some attractive features. A “score card” is presented in which the two alternatives - mixed neutrinos or a mixed sun - are handicapped.

  7. Global constraints on heavy neutrino mixing

    CERN Document Server

    Fernandez-Martinez, Enrique; Lopez-Pavon, Jacobo

    2016-01-01

    We derive general constraints on the mixing of heavy Seesaw neutrinos with the SM fields from a global fit to present flavour and electroweak precision data. We explore and compare both a completely general scenario, where the heavy neutrinos are integrated out without any further assumption, and the more constrained case were only 3 additional heavy states are considered. The latter assumption implies non-trivial correlations in order to reproduce the correct neutrino masses and mixings as observed by oscillation data and thus some qualitative differences can be found with the more general scenario. The relevant processes analyzed in the global fit include searches for Lepton Flavour Violating (LFV) decays, probes of the universality of weak interactions, CKM unitarity bounds and electroweak precision data. In particular, a comparative and detailed study of the present and future sensitivity of the different LFV experiments is performed. We find a mild $1-2\\sigma$ preference for non-zero heavy neutrino mixin...

  8. Democratic Neutrino Mixing and Radiative Corrections

    OpenAIRE

    Xing, Zhi-zhong

    2000-01-01

    The renormalization effect on a specific ansatz of lepton mass matrices, arising naturally from the breaking of flavor democracy for charged leptons and that of mass degeneracy for light neutrinos, is studied from a superhigh energy scale M_0 \\sim 10^{13} GeV to the electroweak scale in the framework of the minimal supersymmetric standard model. We find that the democratic neutrino mixing pattern obtained from this ansatz may in general be instable against radiative corrections. With the help...

  9. On entanglement in neutrino mixing and oscillations

    International Nuclear Information System (INIS)

    We report on recent results about entanglement in the context of particle mixing and oscillations. We study in detail single-particle entanglement arising in two-flavor neutrino mixing. The analysis is performed first in the context of Quantum Mechanics, and then for the case of Quantum Field Theory.

  10. On entanglement in neutrino mixing and oscillations

    CERN Document Server

    Blasone, M; De Siena, S; Illuminati, F

    2010-01-01

    We report on recent results about entanglement in the context of particle mixing and oscillations. We study in detail single-particle entanglement arising in two-flavor neutrino mixing. The analysis is performed first in the context of Quantum Mechanics, and then for the case of Quantum Field Theory.

  11. On entanglement in neutrino mixing and oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, Massimo; Dell' Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio, E-mail: blasone@sa.infn.i [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy)

    2010-06-01

    We report on recent results about entanglement in the context of particle mixing and oscillations. We study in detail single-particle entanglement arising in two-flavor neutrino mixing. The analysis is performed first in the context of Quantum Mechanics, and then for the case of Quantum Field Theory.

  12. Bounds on neutrino mixing with exotic singlet neutrinos

    Indian Academy of Sciences (India)

    J K Singhal; Sardar Singh; Ashok K Nagawat; N K Sharma

    2002-09-01

    We examine the effects of mixing induced non-diagonal light–heavy neutrino weak neutral currents on the amplitude for the process $v_{a}\\overline{v}_{a}→ ZZ$ (with $a = e$; or ). By imposing constraint that the amplitude should not exceed the perturbative unitarity limit at high energy $(\\sqrt{s}=)$, we obtain bounds on light–heavy neutrino mixing parameter $\\sin^{2}^{v_{a}}_{L}$ where $^{v_{a}}_{L}$ is the mixing angle. In the case of one heavy neutrino (mass $m_{}$) or mass degenerate heavy neutrinos, for $ = 1$ TeV, no bound is obtained for $m_{} < 0:50$ TeV. However, $\\sin^{2}^{v_{a}}_{L}≤ 3:8× 10^{-6}$ for $m_{} = 5$ TeV and $\\sin^{2} ^{v_{a}}_{L}≤ 6.0× 10^{-8}$ for $m_{} = 10$ TeV. For = ∞, no constraint is obtained for $m_{} < 0:99$ TeV and $\\sin^{2} ^{v_{a}}_{L}≤ 3.8× 10^{-2}$ (for $m_{} = 5$ TeV) and $\\sin^{2}^{v_{a}}_{L}≤ 9.6× 10^{-3}$ (for $m_{} = 10$ TeV).

  13. Precise predictions of neutrino mixing angles and $CP$ phase

    CERN Document Server

    Abbas, Gauhar

    2016-01-01

    The neutrino mixing parameters are studied using renormalization-group evolution of Dirac neutrinos with recently proposed parameterization of the neutrino mixing angles referred as `high-scale mixing relations'. The correlations among all neutrino mixing and $CP$ violating parameters are investigated. The predictions for the neutrino mixing angles and the $CP$ phase are precise and could be easily tested by ongoing and future experiments. We observe that the high scale mixing unification hypothesis is incompatible with Dirac neutrinos due to updated experimental data.

  14. 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.

  15. Global constraints on heavy neutrino mixing

    Science.gov (United States)

    Fernandez-Martinez, Enrique; Hernandez-Garcia, Josu; Lopez-Pavon, Jacobo

    2016-08-01

    We derive general constraints on the mixing of heavy Seesaw neutrinos with the SM fields from a global fit to present flavour and electroweak precision data. We explore and compare both a completely general scenario, where the heavy neutrinos are integrated out without any further assumption, and the more constrained case were only 3 additional heavy states are considered. The latter assumption implies non-trivial correlations in order to reproduce the correct neutrino masses and mixings as observed by oscillation data and thus some qualitative differences can be found with the more general scenario. The relevant processes analyzed in the global fit include searches for Lepton Flavour Violating (LFV) decays, probes of the universality of weak interactions, CKM unitarity bounds and electroweak precision data. In particular, a comparative and detailed study of the present and future sensitivity of the different LFV experiments is performed. We find a mild 1-2σ preference for non-zero heavy neutrino mixing of order 0.03-0.04 in the electron and tau sectors. At the 2σ level we derive bounds on all mixings ranging from 0.1 to 0.01 with the notable exception of the e - μ sector with a more stringent bound of 0.005 from the μ → eγ process.

  16. $\\Delta(27)$ family symmetry and neutrino mixing

    CERN Document Server

    Varzielas, Ivo de Medeiros

    2015-01-01

    The observed neutrino mixing, having a near maximal atmospheric neutrino mixing angle and a large solar mixing angle, is close to tri-bi-maximal. This structure may be related to the existence of a discrete non-Abelian family symmetry. In this paper the family symmetry is the non-Abelian discrete group $\\Delta(27)$, a subgroup of $SU(3)$ with triplet and anti-triplet representations. Different frameworks are constructed in which the mixing follows from combining fermion mass terms with the vacuum structure enforced by the discrete symmetry. Mass terms for the fermions originate from familon triplets, anti-triplets or both. Vacuum alignment for the family symmetry breaking familons follows from simple invariants.

  17. Bimaximal Neutrino Mixing with Discrete Flavour Symmetries

    CERN Document Server

    Merlo, Luca

    2011-01-01

    In view of the fact that the data on neutrino mixing are still compatible with a situation where Bimaximal mixing is valid in first approximation and it is then corrected by terms of order of the Cabibbo angle, we present examples where these properties are naturally realized. The models are supersymmetric in 4-dimensions and based on the discrete non-Abelian flavour symmetry S4.

  18. Neutrino mass and mixing with discrete symmetry

    Science.gov (United States)

    King, Stephen F.; Luhn, Christoph

    2013-05-01

    This is a review paper 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 see-saw 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 mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A4, S4 and Δ(96).

  19. Schemes and Mechanisms of Neutrino Mixings (Oscillations) and a Solution of the Sun Neutrinos Deficit Problem

    OpenAIRE

    Beshtoev, Kh. M.

    2004-01-01

    Three schemes of neutrino mixings (oscillations) are proposed. The problems of origin of angle mixings, with the law of energy-momentum conservation and disintegration of neutrino as wave pocket are solved. These two schemes belong to mass mixings schemes, where mixing angles and oscillation lengths are expressed via elements of mass matrix. The third scheme belongs to the charge mixings scheme, where mixing parameters are expressed via neutrino weak charges, as it takes place in the vector d...

  20. Baryogenesis through mixing of heavy Majorana neutrinos

    CERN Document Server

    Pilaftsis, Apostolos

    1999-01-01

    We review the scenario of baryogenesis through leptogenesis induced by the out-of-equilibrium decays of heavy neutrinos. We pay special attention to the resonant phenomenon of CP violation through mixing of two nearly degenerate heavy Majorana neutrinos and show how unitarity and CPT invariance is maintained within the resummation approach. An important consequence of this is that the leptogenesis scale may be as low as 1 TeV, even for models with universal Yukawa couplings. We briefly discuss the impact of finite temperature effects and low-energy constraints to the afore-mentioned mechanism of CP violation.

  1. 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...

  2. Tri-Bimaximal Mixing and the Neutrino Oscillation Data

    CERN Document Server

    Harrison, P F; Scott, W G

    2002-01-01

    Following recent results from the SNO solar neutrino experiment and the K2K long-baseline neutrino experiment, the combined existing data on neutrino oscillations now point strongly to a specific form for the lepton mixing matrix, with effective bimaximal mixing of $\

  3. Neutrino Flavor Tagging in a Four-Neutrino Mixing and Oscillation Model

    CERN Document Server

    Lipmanov, E M

    1999-01-01

    A neutrino mass dominance quantity is introduced for tagging the neutrino flavor in the phenomenological two-parameter four neutrino mixing matrix with two neutrino mass doublets and thorough maximal neutrino doublet mixing. While there is no hierarchy of the neutrino masses in the neutrino flavor eigenstates of this model, it may rather be a special hierarchy of the mass dominance ratios in these eigenstates. A neutrino flavor hierarchy condition is suggested: a direct link between the neutrino flavor and the flavor of the charged leptons which interconnects the two mixing angles, theta and phi, via the charged lepton mass ratios, with the net result tg^2 phi = (tg^2 theta)^gamma, gamma ~ 2.06. It leads to distinct inferences testable at SNO and Super-K.

  4. Large neutrino mixing from renormalization group evolution

    International Nuclear Information System (INIS)

    The renormalization group evolution equation for two neutrino mixing is known to exhibit nontrivial fixed point structure corresponding to maximal mixing at the weak scale. The presence of the fixed point provides a natural explanation of the observed maximal mixing of νμ - ντ, if the νμ and ντ are assumed to be quasi-degenerate at the seesaw scale without constraining the mixing angles at that scale. In particular, it allows them to be similar to the quark mixings as in generic grand unified theories. We discuss implementation of this program in the case of MSSM and find that the predicted mixing remains stable and close to its maximal value, for all energies below the O(TeV) SUSY scale. We also discuss how a particular realization of this idea can be tested in neutrinoless double beta decay experiments. (author)

  5. 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}.

  6. Democratic Neutrino Mixing and Radiative Corrections

    CERN Document Server

    Xing, Z

    2001-01-01

    The renormalization effect on a specific ansatz of lepton mass matrices, arising naturally from the breaking of flavor democracy for charged leptons and that of mass degeneracy for light neutrinos, is studied from a superhigh energy scale M_0 \\sim 10^{13} GeV to the electroweak scale in the framework of the minimal supersymmetric standard model. We find that the democratic neutrino mixing pattern obtained from this ansatz may in general be instable against radiative corrections. With the help of similar flavor symmetries we prescribe a slightly different scheme of lepton mass matrices at the scale M_0, from which the democratic mixing pattern of lepton flavors can be achieved, after radiative corrections, at the experimentally accessible scales.

  7. Democratic neutrino mixing and radiative corrections

    Science.gov (United States)

    Xing, Zhi-Zhong

    2001-03-01

    The renormalization effect on a specific ansatz of lepton mass matrices, arising naturally from the breaking of flavor democracy for charged leptons and that of mass degeneracy for light neutrinos, is studied from a superhigh energy scale M0~1013 GeV to the electroweak scale in the framework of the minimal supersymmetric standard model. We find that the democratic neutrino mixing pattern obtained from this ansatz may in general be unstable against radiative corrections. With the help of similar flavor symmetries we prescribe a slightly different scheme of lepton mass matrices at the scale M0, from which the democratic mixing pattern of lepton flavors can be achieved, after radiative corrections, at the experimentally accessible scales.

  8. 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.

  9. Theory of Neutrino Masses and Mixing

    CERN Document Server

    González-Garciá, M Concepción

    2003-01-01

    In this talk I will review our present knowledge on neutrino masses and mixing trying to emphasize what has been definitively proved and what is in the process of being probed. I will also discuss the most important theoretical implications of these results: the existence of new physics, the estimate of the scale of this new physics as well as some other possible consequences such as leptogenesis origin of the baryon asymmetry.

  10. Radiative magnification of neutrino mixings and a natural explanation of the neutrino anomalies

    CERN Document Server

    Balaji, K R S; Mohapatra, Rabindra N; Parida, M K; Dighe, Amol S.

    2000-01-01

    We show that the neutrino mixing pattern with the large mixing required forthe atmospheric neutrino problem and the small mixing angle MSW solution forthe solar neutrino problem can be naturally generated through radiativemagnification, even though all the mixing angles at the seesaw scale may besmall. This can account for the neutrino anomalies as well as the CHOOZconstraints in the context of quark-lepton unified theories, where the quarkand lepton mixing angles are expected to be similar in magnitude at the highscale. We also indicate the 4$\

  11. Calculating error bars for neutrino mixing parameters

    CERN Document Server

    Burroughs, H R; Escamilla-Roa, J; Latimer, D C; Ernst, D J

    2012-01-01

    One goal of contemporary particle physics is to determine the mixing angles and mass-squared differences that constitute the phenomenological constants that describe neutrino oscillations. Of great interest are not only the best fit values of these constants but also their errors. Some of the neutrino oscillation data is statistically poor and cannot be treated by normal (Gaussian) statistics. To extract confidence intervals when the statistics are not normal, one should not utilize the value for chisquare versus confidence level taken from normal statistics. Instead, we propose that one should use the normalized likelihood function as a probability distribution; the relationship between the correct chisquare and a given confidence level can be computed by integrating over the likelihood function. This allows for a definition of confidence level independent of the functional form of the !2 function; it is particularly useful for cases in which the minimum of the !2 function is near a boundary. We present two ...

  12. On non-unitary lepton mixing and neutrino mass observables

    International Nuclear Information System (INIS)

    There are three observables related to neutrino mass, namely the kinematic mass in direct searches, the effective mass in neutrino-less double beta decay, and the sum of neutrino masses in cosmology. In the limit of exactly degenerate neutrinos there are very simple relations between those observables, and we calculate corrections due to non-zero mass splitting. We discuss how the possible non-unitarity of the lepton mixing matrix may modify these relations and find in particular that corrections due to non-unitarity can exceed the corrections due to mass splitting. We furthermore investigate constraints from neutrino-less double beta decay on mass and mixing parameters of heavy neutrinos in the type I see-saw mechanism. There are constraints from assuming that heavy neutrinos are exchanged, and constraints from assuming light neutrino exchange, which arise from an exact see-saw relation. The latter has its origin in the unitarity violation arising in see-saw scenarios. We illustrate that the limits from the latter approach are much stronger. The drastic impact of the new limit on inverse neutrino-less double beta decay (e-e-→W-W-) is studied. We furthermore discuss neutrino mixing in case there is one or more light sterile neutrinos. Neutrino oscillation probabilities for long baseline neutrino oscillation experiments are considered, and the analogy to general non-unitarity phenomenology, such as zero-distance effects, is pointed out.

  13. 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.

  14. Neutrino Mass and Mixing in the Seesaw Playground

    CERN Document Server

    King, Stephen F

    2015-01-01

    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, focussing on the Littlest Seesaw and its distinctive predictions.

  15. The case for mixed dark matter from sterile neutrinos

    CERN Document Server

    Lello, Louis

    2015-01-01

    Sterile neutrinos are $SU(2)$ singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the cosmological production of heavy neutrinos via \\emph{standard model charged and neutral current vertices} under a minimal set of assumptions: i) the mass basis contains a hierarchy of heavy neutrinos, ii) these have very small mixing angles with the active (flavor) neutrinos, iii) standard model particles, including light (active-like) neutrinos are in thermal equilibrium. If kinematically allowed, the same weak interaction processes that produce active-like neutrinos also produce the heavier species. We introduce the quantum kinetic equations that describe their production, freeze out and decay and discuss the various processes that lead to their production in a wide range of temperatures assessing their feasibility as dark matter candidates. We identify processes in which finite temperature collective excitations may lead...

  16. Renormalisation Group Corrections to Neutrino Mixing Sum Rules

    CERN Document Server

    Gehrlein, J; Spinrath, M; Titov, A V

    2016-01-01

    Neutrino mixing sum rules are common to a large class of models based on the (discrete) symmetry approach to lepton flavour. In this approach the neutrino mixing matrix $U$ is assumed to have an underlying approximate symmetry form $\\tilde{U}_{\

  17. Neutrino Mixing Angles in Sequential Dominance to NLO and NNLO

    CERN Document Server

    Antusch, S; King, S F

    2010-01-01

    Neutrinos with hierarchical masses and two large mixing angles may naturally originate from sequential dominance (SD). Within this framework we present analytic expressions for the neutrino mixing angles including the next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) corrections arising from the second lightest and lightest neutrino masses. The analytic results for neutrino mixing angles in SD presented here, including the NLO and NNLO corrections, are applicable to a wide class of models and may provide useful insights when confronting the models with data from high precision neutrino experiments. We also point out that for special cases of SD corresponding to form dominance (FD) the NLO and NNLO corrections both vanish. For example we study tri-bimaximal (TB) mixing via constrained sequential dominance (CSD) which involves only a NNLO correction and tri-bimaximal-reactor (TBR) mixing via partially constrained sequential dominance (PCSD) which involves a NLO correction suppressed by the sm...

  18. Seesaw neutrino masses and mixing with extended democracy

    CERN Document Server

    Joaquim, F R

    2001-01-01

    In the context of a minimal extension of the Standard Model with three extra heavy right-handed neutrinos, we propose a model for neutrino masses and mixing based on the hipothesis of a complete alignment of the lepton mass matrices in flavour space. Considering a uniform quasi-democratic structure for these matrices, we show that, in the presence of a highly hierarchical right-handed neutrino mass spectrum, the effective neutrino mass matrix, obtained through the seesaw mechanism, can reproduce all the solutions of the solar neutrino problem.

  19. Seesaw neutrino masses and mixing with extended democracy

    International Nuclear Information System (INIS)

    In the context of a minimal extension of the Standard Model with three extra heavy right-handed neutrinos, we propose a model for neutrino masses and mixing based on the hipothesis of a complete alignment of the lepton mass matrices in flavour space. Considering a uniform quasi-democratic structure for these matrices, we show that, in the presence of a highly hierarchical right-handed neutrino mass spectrum, the effective neutrino mass matrix, obtained through the seesaw mechanism, can reproduce all the solutions of the solar neutrino problem

  20. 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.

  1. Supersymmetric Neutrino Masses and Mixing with R-parity Violation

    CERN Document Server

    Chun, E J; Kim, C W; Lee, U W

    1999-01-01

    In the context of the minimal supersymmetric standard model, nonzero neutrino masses and mixing can be generated through renormalizable lepton number (and thus R-parity) violating operators. It is examined whether neutrino mass matrices from tree and one-loop contributions can account for two mass-squared differences and mixing angles that explain current experimental data. By accommodating, in particular, the solar and atmospheric neutrino data, we find interesting restrictions not only on the free parameters of the theory, such as lepton number violating couplings and soft-parameters, but also on the oscillation parameters of atmospheric neutrinos.

  2. Limits on sterile neutrino mixing using atmospheric neutrinos in Super-Kamiokande

    OpenAIRE

    collaboration, The Super-Kamiokande; :; Abe, K.; Haga, Y.; Hayato, Y.; Ikeda, M; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.(University of Tokyo, Institute for Cosmic Ray Research, Kamioka Observatory, Kamioka, Japan); Nakano, Y.; Nakayama, S.; Sekiya, H.

    2014-01-01

    We present limits on sterile neutrino mixing using 4,438 live-days of atmospheric neutrino data from the Super-Kamiokande experiment. We search for fast oscillations driven by an eV$^2$-scale mass splitting and for oscillations into sterile neutrinos instead of tau neutrinos at the atmospheric mass splitting. When performing both these searches we assume that the sterile mass splitting is large, allowing $\\sin^2(\\Delta m^2 L/4E)$ to be approximated as $0.5$, and we assume that there is no mix...

  3. Particle Physics Seminar: Towards 3+1 Neutrino Mixing

    CERN Multimedia

    Geneva University

    2011-01-01

    GENEVA UNIVERSITY Ecole de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday  12 October  2011 PARTICLE PHYSICS SEMINAR at 17.00 hrs – Stückelberg Auditorium “Towards 3+1 Neutrino Mixing” Par Prof. Carlo Giunti, INFN Torino I will review the recent experimental indications in favor of  short-baseline neutrino oscillations. I will discuss their interpretation in the framework of neutrino mixing schemes with one or more sterile neutrinos which have masses around the eV scale. Taking into account also cosmological constraints, I will present arguments in favor of 3+1 neutrino mixing with one sterile neutrino at the eV scale. Information : http://dpnc.unige.ch/seminaire/annonce.html Organizer : G. Pasztor

  4. The case for mixed dark matter from sterile neutrinos

    Science.gov (United States)

    Lello, Louis; Boyanovsky, Daniel

    2016-06-01

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

  5. 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.

  6. Effects of active-sterile neutrino mixing during primordial nucleosynthesis

    CERN Document Server

    Civitarese, Osvaldo; Saez, Maria Manuela

    2016-01-01

    In the present work, we discuss the effects of the inclusion of sterile-active neutrino oscillations during the production of primordial light-nuclei. We assume that the sterile neutrino mass-eigenstate might oscillate with the two lightest active neutrino mass- eigenstates, with mixing angles ${\\phi}_1$ and ${\\phi}_2$. We also allow a constant renormalization (represented by a parameter (${\\zeta}$)) of the sterile neutrino occupation factor. Taking ${\\zeta}$ and the mixing angles as free parameters, we have computed distribution functions of active and sterile neutrinos and primordial abundances. Using observable data we set constrains in the free parameters of the model. It is found that the data on primordial abundances are consistent with small mixing angles and with a value of ${\\zeta}$ smaller than 0.65 at 3${\\sigma}$ level.

  7. Neutrino Flavor Oscillations without Flavor Mixing Angles

    CERN Document Server

    Dienes, Keith R; Dienes, Keith R.; Sarcevic, Ina

    2001-01-01

    We demonstrate that sizable neutrino flavor oscillations can be generated in a model with large extra spacetime dimensions even if the physics on the brane is flavor-diagonal, the bulk neutrino theory is flavor-neutral, and the brane/bulk couplings are flavor-blind. We also discuss several phenomenological aspects of the ``bulk-mediated'' neutrino oscillations inherent in this model. [Based on talks given at Neutrino 2000 (Sudbury, Canada, June 2000), the Aspen Workshop on Neutrinos with Mass (Aspen, Colorado, July 2000), and DARK 2000 (Heidelberg, Germany, July 2000).

  8. Low energy threshold corrections to neutrino masses and mixing angles

    Energy Technology Data Exchange (ETDEWEB)

    Chankowski, P.H.; Wasowicz, P. [Institute of Theoretical Physics, Warsaw University (Poland)

    2002-03-01

    We compute the low energy threshold corrections to neutrino masses and mixing in the standard model (SM) and its minimal supersymmetric version, using the effective theory technique. We demonstrate that they stabilize the results for neutrino masses and mixing with respect to the choice of the scale to which the renormalization group (RG) equation is integrated. (This confirms the correctness of the recent re-derivation of the RGE for the SM in hep-ph/0108005.) Since, as is known, those corrections are potentially very important for phenomenology we derive for them the explicit formulae that can be applied to specific models of neutrino masses and mixing. (orig.)

  9. Finite quantum corrections to the tribimaximal neutrino mixing

    CERN Document Server

    Araki, Takeshi; Xing, Zhi-zhong

    2010-01-01

    We calculate finite quantum corrections to the tribimaximal neutrino mixing pattern V_TB in three generic classes of neutrino mass models. We show that three flavor mixing angles can all depart from their tree-level results described by V_TB, and the Dirac CP-violating phase can radiatively arise from two Majorana CP-violating phases. This theoretical scheme offers a new way to understand why one neutrino mixing angle is naturally small and how three CP-violating phases are presumably correlated.

  10. Seesaw Neutrino Masses with Large Mixings from Dimensional Deconstruction

    CERN Document Server

    Balaji, K R S; Seidl, G

    2003-01-01

    We demonstrate how the dimension-five seesaw operator which generates neutrino masses and mixings can have a dynamical origin in dimensional deconstruction models. Light neutrino masses arise in such a scenario from the seesaw scale which corresponds to the inverse lattice spacing. It is shown that the deconstructing limit naturally prefers maximal leptonic mixing. Higher-order corrections which are allowed by gauge invariance can transform the bi-maximal into a bi-large mixing. These terms may appear to be non-renormalizable at scales smaller than the deconstruction scale. We quantitatively outline all relevant features for a few example field theories which accomodate current neutrino data.

  11. Solar neutrinos and the MSW effect for three-neutrino mixing

    Science.gov (United States)

    Shi, X.; Schramm, David N.

    1991-01-01

    Researchers considered three-neutrino Mikheyev-Smirnov-Wolfenstein (MSW) mixing, assuming m sub 3 is much greater than m sub 2 is greater than m sub 1 as expected from theoretical consideration if neutrinos have mass. They calculated the corresponding mixing parameter space allowed by the Cl-37 and Kamiokande 2 experiments. They also calculated the expected depletion for the Ga-71 experiment. They explored a range of theoretical uncertainty due to possible astrophysical effects by varying the B-8 neutrino flux and redoing the MSW mixing calculation.

  12. Constraints on neutrino mixing angle theta_13 and Supernova neutrino fluxes from the LSD neutrino signal from SN1987A

    CERN Document Server

    Lychkovskiy, O

    2006-01-01

    Detection of 5 events by the Liquid Scintillation Detector (LSD) on February, 23, 1987 was recently interpreted as a detection of the electron neutrino flux from the first stage of the two-stage Supernova collapse. We show that, if neutrino mass hierarchy is normal, such interpretation excludes values of neutrino mixing angle \\theta_{13} larger than 3\\cdot 10^{-2}, independently of the particular Supernova collapse model. Also constraints on the original fluxes of neutrinos and antineutrinos of different flavours are obtained.

  13. 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...

  14. Neutrino masses and mixing in A5 with flavor antisymmetry

    Science.gov (United States)

    Joshipura, Anjan S.; Nath, Newton

    2016-08-01

    We discuss the consequences of assuming that the (Majorana) neutrino mass matrix Mν and the charged lepton mass matrix Ml satisfy SνTMνSν=-Mν and Tl†MlMl†Tl=MlMl† with respect to some discrete groups Sν and Tl contained in A5. These assumptions lead to a neutrino mass spectrum with two degenerate and one massless neutrino and also constrain mixing among them. We derive possible mixing patterns following from the choices Sν=Z2 , Z2×Z2 , and Tl=Z2,Z2×Z2,Z3,Z5 as subgroups of A5. One predicts the maximal atmospheric neutrino mixing angle θ23 and μ -τ reflection symmetry in a large number of cases, but it is also possible to obtain nonmaximal values for θ23. Only the third column of the neutrino mixing matrix can be obtained at the leading order due to degeneracy in masses of two of the neutrinos. We take up a specific example within the A5 group and identify Higgs vacuum expectation values which realize the above assumptions. Nonleading terms present in this example are shown to lead to splitting among degenerate pairs and a consistent description of both neutrino masses and mixing angles.

  15. Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters.

    Science.gov (United States)

    Ahmad, Q R; Allen, R C; Andersen, T C; Anglin, J D; Barton, J C; Beier, E W; Bercovitch, M; Bigu, J; Biller, S D; Black, R A; Blevis, I; Boardman, R J; Boger, J; Bonvin, E; Boulay, M G; Bowler, M G; Bowles, T J; Brice, S J; Browne, M C; Bullard, T V; Bühler, G; Cameron, J; Chan, Y D; Chen, H H; Chen, M; Chen, X; Cleveland, B T; Clifford, E T H; Cowan, J H M; Cowen, D F; Cox, G A; Dai, X; Dalnoki-Veress, F; Davidson, W F; Doe, P J; Doucas, G; Dragowsky, M R; Duba, C A; Duncan, F A; Dunford, M; Dunmore, J A; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Ferraris, A P; Ford, R J; Formaggio, J A; Fowler, M M; Frame, K; Frank, E D; Frati, W; Gagnon, N; Germani, J V; Gil, S; Graham, K; Grant, D R; Hahn, R L; Hallin, A L; Hallman, E D; Hamer, A S; Hamian, A A; Handler, W B; Haq, R U; Hargrove, C K; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Hepburn, J D; Heron, H; Hewett, J; Hime, A; Howe, M; Hykawy, J G; Isaac, M C P; Jagam, P; Jelley, N A; Jillings, C; Jonkmans, G; Kazkaz, K; Keener, P T; Klein, J R; Knox, A B; Komar, R J; Kouzes, R; Kutter, T; Kyba, C C M; Law, J; Lawson, I T; Lay, M; Lee, H W; Lesko, K T; Leslie, J R; Levine, I; Locke, W; Luoma, S; Lyon, J; Majerus, S; Mak, H B; Maneira, J; Manor, J; Marino, A D; McCauley, N; McDonald, A B; McDonald, D S; McFarlane, K; McGregor, G; Meijer Drees, R; Mifflin, C; Miller, G G; Milton, G; Moffat, B A; Moorhead, M; Nally, C W; Neubauer, M S; Newcomer, F M; Ng, H S; Noble, A J; Norman, E B; Novikov, V M; O'Neill, M; Okada, C E; Ollerhead, R W; Omori, M; Orrell, J L; Oser, S M; Poon, A W P; Radcliffe, T J; Roberge, A; Robertson, B C; Robertson, R G H; Rosendahl, S S E; Rowley, J K; Rusu, V L; Saettler, E; Schaffer, K K; Schwendener, M H; Schülke, A; Seifert, H; Shatkay, M; Simpson, J J; Sims, C J; Sinclair, D; Skensved, P; Smith, A R; Smith, M W E; Spreitzer, T; Starinsky, N; Steiger, T D; Stokstad, R G; Stonehill, L C; Storey, R S; Sur, B; Tafirout, R; Tagg, N; Tanner, N W; Taplin, R K; Thorman, M; Thornewell, P M; Trent, P T; Tserkovnyak, Y I; Van Berg, R; Van de Water, R G; Virtue, C J; Waltham, C E; Wang, J-X; Wark, D L; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wittich, P; Wouters, J M; Yeh, M

    2002-07-01

    The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

  16. Leptogenesis from Oscillations of Heavy Neutrinos with Large Mixing Angles

    CERN Document Server

    Drewes, Marco; Gueter, Dario; Klaric, Juraj

    2016-01-01

    The extension of the Standard Model by heavy right-handed neutrinos can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the Universe via leptogenesis. If the mass of the heavy neutrinos is below the electroweak scale, they may be found at LHCb, BELLE II, the proposed SHiP experiment or a future high-energy collider. In this mass range, the baryon asymmetry is generated via $CP$-violating oscillations of the heavy neutrinos during their production. We study the generation of the baryon asymmetry of the Universe in this scenario from first principles of non-equilibrium quantum field theory, including spectator processes and feedback effects. We eliminate several uncertainties from previous calculations and find that the baryon asymmetry of the Universe can be explained with larger heavy neutrino mixing angles, increasing the chance for an experimental discovery. For the limiting cases of fast and strongly overdamped oscillations of right-handed neutrinos,...

  17. Localization on Fat Branes as the Source of Neutrino Mixing

    CERN Document Server

    Gozdz, M

    2004-01-01

    The localization of fermions in extra dimensions, proposed by Arkani-Hamed and Schmaltz, is discussed as the source of the phenomenon of particle mixing. We work out the example of neutrinos in detail.

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

    International Nuclear Information System (INIS)

    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.

  19. Neutrinos How Do They Mix and Violate CP?

    CERN Document Server

    Fritzsch, Harald; Fritzsch, Harald; Xing, Zhi-zhong

    2000-01-01

    We discuss a simple model of lepton mixing and CP violation based on the flavor democracy of charge leptons and the mass degeneracy of neutrinos. A nearly bi-maximal flavor mixing pattern, which is favored by current data on atmospheric and solar neutrino oscillations, emerges naturally from this model after explicit symmetry breaking. The rephasing-invariant strength of CP or T violation can be as large as one percent, leading to significant probability asymmetries between \

  20. Nonmaximal neutrino mixing at NOvA from nonstandard interactions

    CERN Document Server

    Liao, Jiajun; Whisnant, Kerry

    2016-01-01

    Muon neutrino disappearance measurements at NOvA suggest that maximal \\theta_{23} is excluded at the 2.5\\sigma CL. This is in mild tension with T2K data which prefer maximal mixing. Considering that NOvA has a much longer baseline than T2K, we point out that the apparent departure from maximal mixing in NOvA may be a consequence of nonstandard neutrino propagation in matter.

  1. The mixing angle as a function of neutrino mass ratio

    CERN Document Server

    Roy, Subhankar

    2016-01-01

    In the quark sector, we experience a correlation between the mixing angles and the mass ratios. A partial realization of the similar tie-up in the neutrino sector helps to constrain the parametrization of masses and mixing, and hints for a predictive framework. We derive five hierarchy dependent textures of neutrino mass matrix with minimum number of parameters ($\\leq\\,4$), following a model-independent strategy.

  2. Status of Tri/Bi-Maximal Neutrino Mixing

    CERN Document Server

    Harrison, P F

    2004-01-01

    Tri/bi-maximal mixing (TBM) is a specific lepton mixing ansatz, which describes the trend of the current neutrino oscillation data, in particular the recent SNO and KAMLAND results. The significant feature of TBM in this respect is |U_e2|^2=|U_m2|^2=|U_t2|^2=1/3, and we say that the nu_2 is tri-maximally mixed. We have generalised the TBM ansatz to a generic mixing matrix with the nu_2 trimaximally mixed, whereby the neutrino mass matrix in the lepton flavour basis takes the form of a general S3 group matrix (3 x 3 `magic-square'). In exact TBM the charged-lepton mass matrix in the neutrino mass basis (where the neutrino mass matrix is diagonal) takes the form of a general S3 class operator. The neutrino mass matrix in the flavour basis is a particular S3 group matrix which is also an S1 C S2 C S3 group-chain class operator, whereby the neutrino mass eigenstates are distinguished by their `mutativity' (M_i = +/-1) and `democracy' (D_i = 0,3) which are both good quantum numbers in exact TBM.

  3. Limits on Sterile Neutrino Mixing using Atmospheric Neutrinos in Super-Kamiokande

    CERN Document Server

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

    2014-01-01

    We present limits on sterile neutrino mixing using 4,438 live-days of atmospheric neutrino data from the Super-Kamiokande experiment. We search for fast oscillations driven by an eV$^2$-scale mass splitting and for oscillations into sterile neutrinos instead of tau neutrinos at the atmospheric mass splitting. When performing both these searches we assume that the sterile mass splitting is large, allowing $\\sin^2(\\Delta m^2 L/4E)$ to be approximated as $0.5$, and we assume that there is no mixing between electron neutrinos and sterile neutrinos ($|U_{e4}|^2 = 0$). No evidence of sterile oscillations is seen and we limit $|U_{\\mu4}|^2$ to less than 0.041 and $|U_{\\tau4}|^2$ to less than 0.18 for $\\Delta m^2 > 0.8$ eV$^2$ at the 90% C.L. in a 3+1 framework. The approximations that can be made with atmospheric neutrinos allow these limits to be easily applied to 3+N models, and we provide our results in a generic format to allow comparisons with other sterile neutrino models.

  4. Search for sterile neutrino mixing in the muon neutrino to tau neutrino appearance channel with the OPERA detector

    Science.gov (United States)

    Di Crescenzo, A.; OPERA Collaboration

    2016-05-01

    The OPERA experiment observed ν μ → ν τ oscillations in the atmospheric sector. To this purpose the hybrid OPERA detector was exposed to the CERN Neutrinos to Gran Sasso beam from 2008 to 2012, at a distance of 730 km from the neutrino source. Charged-current interactions of ν τ were searched for through the identification of τ lepton decay topologies. The five observed ν τ interactions are consistent with the expected number of events in the standard three neutrino framework. Based on this result, new limits on the mixing parameters of a massive sterile neutrino may be set. Preliminary results of the analysis performed in the 3+1 neutrino framework are here presented.

  5. 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.

  6. 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 ...

  7. Geometric relation for neutrino mixing angles and theta(13)

    CERN Document Server

    Lipmanov, E M

    2011-01-01

    Inspired by the recent T2K discovery of a relatively large theta(13) angle in the neutrino mixing matrix we propose here a simple geometric relation between the three usually thought "independent" neutrino mixing angles - solar {\\theta}12, atmospheric {\\theta}23 and reactor {\\theta}13 ones: cos2(2{\\theta}sol) + cos2(2{\\theta}atm) + cos2(2{\\theta}13) = 1. Using the estimations for the two largest neutrino mixing angles from experimental data analyses in the literature, {\\theta}sol{\\cong} ~ 34.4o, {\\theta}atm{\\cong} ~ 42.8o, the reactor neutrino mixing angle is uniquely predicted {\\theta}13 = 10.8o. In case a little changed data, {\\theta}sol{\\cong} = 34o and {\\theta}atm{\\cong} = 43o the result will be {\\theta}13 =11.2o. And so, the {\\theta}13-value is not very sensitive to the accurate magnitudes of the two largest mixing angles. That prediction for the 'small' neutrino mixing angle is compatible with the latest T2K experimental data with best fit values for the reactor angle ({\\theta}13)bf{\\cong}= 9.7o(11o) fo...

  8. 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.

  9. Overview of Neutrino Mixing Models and Their Mixing Angle Predictions

    OpenAIRE

    Albright, Carl H.

    2009-01-01

    Comment: 5 pages, 6 figures, written version of talk presented at the 11th International Workshop on Neutrino Factories, Superbeams and Beta Beams, Illinois Institute of Technology, Chicago, July 20-25, 2009; abbreviated version of arXiv:0905.0146 which appeared in Proceedings of the 13th International Workshop on Neutrino Telescopes, Venice, March 10-13, 2009

  10. Low energy threshold corrections to neutrino masses and mixing angles

    CERN Document Server

    Chankowski, P H

    2002-01-01

    We compute the low energy threshold corrections to neutrino masses and mixing in the Standard Model (SM) and its minimal supersymmetric version, using the effective theory technique. We demonstrate that they stabilize the renormalization group (RG) running with respect to the choice of the scale to which the RG equation is integrated. This confirms the correctness of the recent re-derivation of the RGE for the SM in hep-ph/0108005. The explicit formulae for the low energy threshold corrections corrections can be applied to specific models of neutrino masses and mixing.

  11. Finite quantum corrections to the tribimaximal neutrino mixing

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Takeshi, E-mail: araki@ihep.ac.c [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Geng, Chao-Qiang, E-mail: geng@phys.nthu.edu.t [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China); Xing Zhizhong, E-mail: xingzz@ihep.ac.c [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2011-05-16

    We calculate finite quantum corrections to the tribimaximal neutrino mixing pattern V{sub TB} in three generic classes of neutrino mass models. We show that three flavor mixing angles can all depart from their tree-level results described by V{sub TB}, among which {theta}{sub 12} is most sensitive to such quantum effects, and the Dirac CP-violating phase can radiatively arise from two Majorana CP-violating phases. This theoretical scheme offers a new way to understand why {theta}{sub 13} is naturally small and how three CP-violating phases are presumably correlated.

  12. Modified Friedberg-Lee symmetry for neutrino mixing

    Science.gov (United States)

    Zhao, Zhen-hua

    2015-12-01

    In this paper, we put forward a special neutrino mass matrix which is invariant under a modified Friedberg-Lee (FL) transformation νe→νe-2 ξ and νμ ,τ→νμ ,τ+ξ with ξ being a space-time independent element of the Grassmann algebra. Compared to the original FL symmetry (with the transformation νe ,μ ,τ→νe ,μ ,τ+ξ ) which results in the TM2 neutrino mixing, the modified FL symmetry will lead us to the TM1 mixing which has a better agreement with the experimental results. While the original FL symmetry has to be broken in order to produce a realistic neutrino mass spectrum, the modified FL symmetry is allowed to remain intact and give us a vanishing m1. A combination of the FL symmetry with the μ -τ reflection symmetry is also discussed.

  13. Implications of neutrino masses and mixing for weak processes

    International Nuclear Information System (INIS)

    A general theory is presented of weak processes involving neutrinos which consistently incorporates the possibility of nonzero neutrino masses and associated lepton mixing. The theory leads to new tests for and bounds on such masses and mixing. These tests make use of (π,K)/sub l2/ decay, nuclear β decay, and μ and tau decays, among others. New experiments at SIN and KEK to apply the tests are mentioned. Further, some implications are discussed for (1) the analysis of the spectral parameters in leptonic decays to determine the Lorentz structure of the weak leptonic couplings; (2) fundamental weak interaction constants such as G/sub μ/, G/sub V/', f/sub π/, f/sub K/, V/sub uq/, q = d or s, m/sub W/, and m/sub Z/; and (3) neutrino propagation

  14. Seesaw neutrino masses with large mixings from dimensional deconstruction

    International Nuclear Information System (INIS)

    We demonstrate a dynamical origin for the dimension-five seesaw operator in dimensional deconstruction models. Light neutrino masses arise from the seesaw scale which corresponds to the inverse lattice spacing. It is shown that the deconstructing limit naturally prefers maximal leptonic mixing. Higher-order corrections which are allowed by gauge invariance can transform the bimaximal into a bilarge mixing. These terms may appear to be nonrenormalizable at scales smaller than the deconstruction scale

  15. 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_\

  16. Discrete Flavor Symmetries and Models of Neutrino Mixing

    CERN Document Server

    Altarelli, Guido

    2010-01-01

    We review the application of non abelian discrete groups to the theory of neutrino masses and mixing, which is strongly suggested by the agreement of the Tri-Bimaximal mixing pattern with experiment. After summarizing the motivation and the formalism, we discuss specific models, based on A4, S4 and other finite groups, and their phenomenological implications, including lepton flavor violating processes, leptogenesis and the extension to quarks. In alternative to Tri-Bimaximal mixing the application of discrete flavor symmetries to quark-lepton complementarity and Bimaximal Mixing is also considered.

  17. Neutrino Mixing and Leptogenesis in $\\mu-\\tau$ Symmetry

    CERN Document Server

    Lashin, E I; Hamzaoui, C; Nasri, S

    2014-01-01

    We study the consequences of the $Z_2$-symmetry behind the $\\mu$-$\\tau$ universality in neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass hierarchies and generate enough lepton asymmetry to interpret the observed baryon asymmetry in the universe. We also show how a specific form of a high-scale perturbation is kept when translated via the seesaw into the low scale domain, where it can accommodate the neutrino mixing data. We finally present a realization of the high scale perturbed texture through addition of matter and extra exact symmetries.

  18. Exploring neutrino mixing with low energy superbeams

    International Nuclear Information System (INIS)

    We explore as clearly as possible the features of neutrino oscillation which are relevant for measurements of the CP violating Kobayashi-Maskawa phase δ and the sign of Δ m132. We focus on the so called low-energy option and discuss principles for optimizing experimental parameters to measure these two quantities simultaneously. Toward the goal, we first formulate a method for obtaining a bird-eye view of the phenomenon of neutrino oscillation by introducing a new powerful tool called the 'CP trajectory diagram in bi-probability space'. It allows us to represent pictorially the three effects separately in a single diagram; effect from genuine CP violation due to the sin δ term, effect from the CP conserving cos δ term, and the fake CP violating effect due to earth matter. By using the CP trajectory diagram we observe that there is a two-fold ambiguity in the determination of δ which is related with the sign of Δ m132. We then address the question of what are the promising options for conceptual design of experiments at low energies which looks for CP violation and at the same time would resolve the two-fold ambiguity. We point out that a version with distance of about 700 km, with a megaton class water Cherenkov detector gives an optimal design which allows simultaneous determination of δ and the sign of Δ m132 in situ. We also point out that there is a possibility that the similar in situ measurement of both quantities can be done at the Phase II of JHF experiment with much shorter baseline, under the assumption of nature's kind setting of δ to the region of sin δ·Δm132<0. A technique of running at high (∼ 1 GeV) and low (∼ 0.5 GeV) beam energies is proposed as a method for better identification of δ. (author)

  19. Large Solar Neutrino Mixing in an Extended Zee Model

    CERN Document Server

    Kitabayashi, T; Kitabayashi, Teruyuki; Yasue, Masaki

    2002-01-01

    The Zee model, which employs the standard Higgs scalar ($\\phi$) with its duplicate ($\\phi^\\prime$) and a singly charged scalar ($h^+$), can utilize two global symmetries associated with the conservation of the numbers of $\\phi$ and $\\phi^\\prime$, $N_{\\phi,\\phi^\\prime}$, where $N_\\phi+N_{\\phi^\\prime}$ coincides with the hypercharge while $N_\\phi-N_{\\phi^\\prime}$ ($\\equiv X$) is a new conserved charge, which is identical to $L_e-L_\\mu-L_\\tau$ for the left-handed leptons. Charged leptons turn out to have $e$-$\\mu$ and $e$-$\\tau$ mixing masses, which are found to be crucial for the large solar neutrino mixing. In an extended version of the Zee model with an extra triplet Higgs scalar (s), neutrino oscillations are described by three steps: 1) the maximal atmospheric mixing is induced by democratic mass terms supplied by $s$ with $X$=2 that can initiate the type II seesaw mechanism for the smallness of these masses; 2) the maximal solar neutrino mixing is triggered by the creation of radiative masses by $h^+$ with...

  20. Neutrino Large Mixing in Universal Yukawa Coupling Model with Small Violation

    CERN Document Server

    Teshima, T; Abe, Y

    2002-01-01

    We have analyzed the possibility that the universal Yukawa coupling (democratic mass matrix) with small violations of Dirac and Majorana neutrinos can induce the large mixing of neutrinos through the seesaw mechanism. The possibility can be achieved by the condition that the violation parameters of Majorana neutrinos are sufficiently smaller than the violation parameters of Dirac neutrinos. Allowed regions of the violation parameters producing the observed neutrino mass hierarchy and large neutrino mixing are not so restricted at present in contrast to the violation parameters for quark sector.

  1. Corrections to scaling neutrino mixing: Non-zero θ13,δCP and baryon asymmetry

    Directory of Open Access Journals (Sweden)

    Rupam Kalita

    2015-05-01

    Full Text Available We study a very specific type of neutrino mass and mixing structure based on the idea of Strong Scaling Ansatz (SSA where the ratios of neutrino mass matrix elements belonging to two different columns are equal. There are three such possibilities, all of which are disfavored by the latest neutrino oscillation data. We focus on the specific scenario which predicts vanishing reactor mixing angle θ13 and inverted hierarchy with vanishing lightest neutrino mass. Motivated by several recent attempts to explain non-zero θ13 by incorporating corrections to a leading order neutrino mass or mixing matrix giving θ13=0, here we study the origin of non-zero θ13 as well as leptonic Dirac CP phase δCP by incorporating two different corrections to scaling neutrino mass and mixing: one, where type II seesaw acts as a correction to scaling neutrino mass matrix and the other, with charged lepton correction to scaling neutrino mixing. Although scaling neutrino mass matrix originating from type I seesaw predicts inverted hierarchy, the total neutrino mass matrix after type II seesaw correction can give rise to either normal or inverted hierarchy. However, charged lepton corrections do not disturb the inverted hierarchy prediction of scaling neutrino mass matrix. We further discriminate between neutrino hierarchies, different choices of lightest neutrino mass and Dirac CP phase by calculating baryon asymmetry and comparing with the observations made by the Planck experiment.

  2. Large neutrino mixing from large discrete symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Neder, Thomas; King, Stephen F.; Stuart, Alexander J. [School of Physics and Astronomy, University of Southampton (United Kingdom)

    2013-07-01

    Several finite groups that are candidates for a flavor symmetry of leptons are investigated. Promising candidates are amongst others the groups Δ(150) and Δ(600). The group theory of these groups as well as results for the lepton mixing parameters resulting from these groups are presented.

  3. Neutrino mass and mixing, and non-accelerator experiments

    International Nuclear Information System (INIS)

    We review the current status of experimental knowledge about neutrinos derived from kinematic mass measurements, neutrino oscillation searches at reactors and accelerators, solar neutrinos, atmospheric neutrinos, and single and double beta decay. The solar neutrino results yield fairly strong and consistent indication that neutrino oscillations are occurring. Other evidence for new physics is less consistent and convincing

  4. 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.

  5. 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.

  6. Doubling of the algebra and neutrino mixing within noncommutative spectral geometry. Doubling of the algebra and neutrino mixing

    Energy Technology Data Exchange (ETDEWEB)

    Gargiulo, Maria Vittoria; Vitiello, Giuseppe [I.N.F.N., Salerno (Italy); Universita di Salerno, Dipartimento di Fisica, Salerno (Italy); Sakellariadou, Mairi [King' s College London, University of London, Department of Physics, London (United Kingdom)

    2014-01-15

    We study the physical implications of the doubling of the algebra, an essential element in the construction of the noncommutative spectral geometry model, proposed by Connes and his collaborators as offering a geometric explanation for the standard model of the strong and electroweak interactions. Linking the algebra doubling to the deformed Hopf algebra, we build Bogoliubov transformations and show the emergence of neutrino mixing. (orig.)

  7. Neutrino Mixing from $\\Delta(6n^2)$ Groups

    CERN Document Server

    Neder, Thomas

    2014-01-01

    Experimentally viable lepton mixing parameters can be predicted in so-called direct flavour models with Majorana neutrinos using $\\Delta(6n^2)$ groups as a flavour group. In direct models, in which the flavour group is broken to a $Z_2\\times Z_2$ subgroup in the neutrino sector, mixing angles and Dirac CP phase are purely predicted from symmetry. General predictions of direct models with $\\Delta(6n^2)$ flavour groups are that all mixing angles are fixed up to a discrete choice and that the Dirac CP phase is $0$ or $\\pi$; Furthermore, the middle column of the mixing matrix is trimaximal which yields the sum rule $\\theta_{23}=45^\\circ \\mp \\theta_{13}/\\sqrt{2}$ depending on the Dirac phase. These predictions of lepton mixing parameters are compatible with recent global fit results or will be tested experimentally in the near future. It is the first time that such predictions have been obtained model-independently for an infinite series of groups.

  8. Exponential parameterization of the neutrino mixing matrix - comparative analysis with different data sets and CP violation

    CERN Document Server

    Zhukovsky, Konstantin

    2016-01-01

    The exponential parameterization of Pontecorvo-Maki-Nakagawa-Sakata mixing matrix for neutrino is used for comparative analysis of different neutrino mixing data. The UPMNS matrix is considered as the element of the SU(3) group and the second order matrix polynomial is constructed for it. The inverse problem of constructing the logarithm of the mixing matrix is addressed. In this way the standard parameterization is related to the exponential parameterization exactly. The exponential form allows easy factorization and separate analysis of the rotation and the CP violation. With the most recent experimental data on the neutrino mixing (May 2016), we calculate the values of the exponential parameterization matrix for neutrinos with account for the CP violation. The complementarity hypothesis for quarks and neutrinos is demonstrated to hold, despite significant change in the neutrino mixing data. The values of the entries of the exponential mixing matrix are evaluated with account for the actual degree of the CP...

  9. Neutrino Mixing and the Frobenius Group T13

    CERN Document Server

    Hartmann, Christine

    2011-01-01

    We show that the Frobenius group $T_{13} = Z_{13} \\rtimes Z_3$ is a suitable family symmetry group to study neutrino oscillations. Our approach is to catalog all possibilities within an effective field theory approach, assuming only SU(2)xU(1) supplemented by family symmetry. We will use tribimaximal mixing as a guide to place a constraint on the otherwise various possibilities. This leads to an exact fit between the neutrino and charged lepton sector. Such a fit has not been achieved with any other group so far. The results of this paper may then be useful in future studies on the compatibility of this Frobenius group with other models and mechanisms.

  10. 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.

  11. 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.

  12. Four-Neutrino Mixing, Oscillations and Big-Bang Nucleosynthesis

    OpenAIRE

    Bilenky, S. M.; Giunti, C.; Grimus, W.; Schwetz, T.

    1998-01-01

    We investigate the implications of the standard Big-Bang Nucleosynthesis constraint on the number of light neutrinos in the framework of the two four-neutrino schemes that are favored by the results of neutrino oscillation experiments.

  13. Flavor democracy and type-II seesaw realization of bilarge neutrino mixing

    International Nuclear Information System (INIS)

    We generalize the democratic neutrino mixing ansatz by incorporating the type-II seesaw mechanism with S(3) flavor symmetry. For only the triplet mass term or only the conventional seesaw term large neutrino mixing can be achieved only by assuming an unnatural suppression of the flavor democracy contribution. We show that bilarge neutrino mixing can naturally appear if the flavor democracy term is strongly suppressed due to significant cancellation between the conventional seesaw and triplet mass terms. Explicit S(3) symmetry breaking yields successful neutrino phenomenology and various testable correlations between the neutrino mass and mixing parameters. Among the results are a normal neutrino mass ordering, 0.005=e3 vertical bar =22θ23>=0.005, positive JCP and moderate cancellation in the effective mass of the neutrinoless double beta decay

  14. 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.

  15. Tri-Bimaximal Neutrino Mixing and Discrete Flavour Symmetries

    CERN Document Server

    Altarelli, Guido; Merlo, Luca

    2013-01-01

    We review the application of non-Abelian discrete groups to Tri-Bimaximal (TB) neutrino mixing, which is supported by experiment as a possible good first approximation to the data. After summarizing the motivation and the formalism, we discuss specific models, mainly those based on A4 but also on other finite groups, and their phenomenological implications, including the extension to quarks. The recent measurements of \\theta_13 favour versions of these models where a suitable mechanism leads to corrections to \\theta_13 that can naturally be larger than those to \\theta_12 and \\theta_23. The virtues and the problems of TB mixing models are discussed, also in connection with lepton flavour violating processes, and the different approaches are compared.

  16. A non-standard CP transformation leading to maximal atmospheric neutrino mixing

    Energy Technology Data Exchange (ETDEWEB)

    Grimus, Walter; Lavoura, Luis

    2004-01-15

    We discuss a neutrino mass matrix M{sub {nu}} originally found by Babu, Ma, and Valle (BMV) and show that this mass matrix can be characterized by a simple algebraic relation. From this relation it follows that atmospheric neutrino mixing is exactly maximal while at the same time an arbitrary mixing angle {theta}{sub 13} of the lepton mixing matrix U is allowed and--in the usual phase convention--CP violation in mixing is maximal; moreover, neither the neutrino mass spectrum nor the solar mixing angle are restricted. We put forward a seesaw extension of the Standard Model, with three right-handed neutrinos and three Higgs doublets, where the family lepton numbers are softly broken by the Majorana mass terms of the right-handed neutrino singlets and the BMV mass matrix results from a non-standard CP symmetry.

  17. Two-texture zeros and near-maximal atmospheric neutrino mixing angle

    Indian Academy of Sciences (India)

    S Dev; Radha Raman Gautam; Lal Singh; Manmohan Gupta

    2016-02-01

    We study the implications of a large value of the effective Majorana neutrino mass for a class of two-texture zero neutrino mass matrices in the flavour basis. We find that these textures predict near-maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. We present the symmetry realization of these textures using the discrete cyclic group Z3. It is found that the texture zeros realized in this work remain stable under the renormalization group running of the effective neutrino mass matrix at one-loop level.

  18. Exponential parameterization of neutrino mixing matrix with account of CP-violation data

    Science.gov (United States)

    Zhukovsky, Konstantin; Melazzini, Francisco

    2016-08-01

    The exponential parameterization of the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix for neutrinos is discussed. The exponential form allows easy factorization and separate analysis of the CP-violating and Majorana terms. Based upon the recent experimental data on the neutrino mixing, the values for the exponential parameterization matrix for neutrinos are determined. The matrix entries for the pure rotational part in charge of the mixing without CP violation are derived. The complementarity hypothesis for quarks and neutrinos is demonstrated. A comparison of the results based on most recent and on old data is presented. The CP-violating parameter value is estimated, based on the so far imprecise experimental indications, regarding CP violation for neutrinos. The unitarity of the exponential parameterization and the CP-violating term transform is confirmed. The transform of the neutrino mass state vector by the exponential matrix with account of CP violation is shown.

  19. Exponential parameterization of neutrino mixing matrix with account for CP-violation data

    CERN Document Server

    Zhukovsky, K

    2016-01-01

    The exponential parameterization of Pontecorvo-Maki-Nakagawa-Sakata mixing matrix for neutrino is discussed. The exponential form allows easy factorization and separate analysis of the CP-violating and Majorana terms. Based upon the recent experimental data on the neutrino mixing, the values for the exponential parameterization matrix for neutrinos are determined. The matrix entries for the pure rotational part in charge of the mixing without CP-violation are derived. The complementarity hypothesis for quarks and neutrinos is demonstrated. The comparison of the results, based on most recent and on old data is held. The CP-violating parameter value is estimated, based on the so far imprecise experimental indications, regarding CP-violation for neutrinos. The unitarity of the exponential parameterisation and the CP-violating term transform is confirmed. The transform of the neutrino mass state vector by the exponential matrix with account for CP-violation is shown.

  20. Corrections to Scaling Neutrino Mixing: Non-zero $\\theta_{13}, \\delta_{CP}$ and Baryon Asymmetry

    CERN Document Server

    Kalita, Rupam; Das, Mrinal Kumar

    2014-01-01

    We study a very specific type of neutrino mass and mixing structure based on the idea of Strong Scaling Ansatz (SSA) where the ratios of neutrino mass matrix elements belonging to two different columns are equal. There are three such possibilities, all of which are disfavored by the latest neutrino oscillation data. We focus on the specific scenario which predicts vanishing reactor mixing angle $\\theta_{13}$ and inverted hierarchy with vanishing lightest neutrino mass. Motivated by several recent attempts to explain non-zero $\\theta_{13}$ by incorporating corrections to a leading order neutrino mass or mixing matrix giving $\\theta_{13}=0$, here we study the origin of non-zero $\\theta_{13}$ as well as leptonic Dirac CP phase $\\delta_{CP}$ by incorporating two different corrections to scaling neutrino mass and mixing: one where type II seesaw acts as a correction to scaling neutrino mass matrix and the other with charged lepton correction to scaling neutrino mixing. Although scaling neutrino mass matrix origina...

  1. Neutrino Mixing With Non-Zero $\\theta_{13}$ In Zee-Babu Model

    CERN Document Server

    Long, H N

    2014-01-01

    The exact solution for the neutrino mass matrix of the Zee-Babu model is derived. Tribimaximal mixing imposes conditions on the Yukawa couplings, from which the normal mass hierarchy is preferred. The derived conditions give a possibility of Majorana maximal $\\mathrm{CP}$ violation in the neutrino sector. We have shown that non-zero $\\theta_{13}$ is generated if Yukawa couplings between leptons almost equal to each other. The model gives some regions of the parameters where neutrino mixing angles and the normal neutrino mass hierarchy obtained consistent with the recent experimental data.

  2. Neutrino mixing with nonzero θ13 in Zee-Babu model

    Science.gov (United States)

    Long, Hoang Ngoc; Vien, Vo Van

    2014-05-01

    The exact solution for the neutrino mass matrix of the Zee-Babu model is derived. Tribimaximal mixing imposes conditions on the Yukawa couplings, from which the normal mass hierarchy is preferred. The derived conditions give a possibility of Majorana maximal CP violation in the neutrino sector. We have shown that nonzero θ13 is generated if Yukawa couplings between leptons almost equal to each other. The model gives some regions of the parameters where neutrino mixing angles and the normal neutrino mass hierarchy obtained are consistent with the recent experimental data.

  3. 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...

  4. 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 ...

  5. Unifying leptogenesis, dark matter and high-energy neutrinos with right-handed neutrino mixing via Higgs portal

    CERN Document Server

    Di Bari, Pasquale; Palomares-Ruiz, Sergio

    2016-01-01

    We revisit a model in which neutrino masses and mixing are described by a two right-handed (RH) neutrino seesaw scenario, implying a strictly hierarchical light neutrino spectrum. A third decoupled RH neutrino, $N_{\\rm DM}$ with mass $M_{\\rm DM}$, plays the role of cold dark matter (DM) and is produced by the mixing with a source RH neutrino, $N_{\\rm S}$ with mass $M_{\\rm S}$, induced by Higgs portal interactions. The same interactions are also responsible for $N_{\\rm DM}$ decays. We discuss in detail the constraints coming from DM abundance and stability conditions, showing that in the hierarchical case ($M_{\\rm DM} \\gg M_{\\rm S}$) there is an allowed window on $M_{\\rm DM}$, which necessarily implies a contribution from DM decays to the high-energy neutrino flux recently detected by IceCube. We also show how the model can explain the matter-antimatter asymmetry of the Universe via leptogenesis in the quasi-degenerate limit. In this case, the DM mass should be within the range 300 GeV $\\lesssim M_{\\rm S} <...

  6. Understanding the linear see-saw neutrino mass relations and large mixing angle MSW solution

    CERN Document Server

    Singh, N N

    2000-01-01

    We study the effective ways for generating the linear see-saw neutrino mass relations and large neutrino mixing angles in two classes of grand unified SO(10) models where the texture of Dirac neutrino mass matrix is related to either the charged lepton mass matrix (case A) or the up-quark mass matrix (case B). We also briefly analyse their stability criteria and they are found to be stable under under radiative corrections at low energies.

  7. 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.

  8. Precise measurement of the weak mixing angle in neutrino-nucleon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Arroyo, C.G.; King, B.J.; Bachmann, K.T.; Bazarko, A.O.; Bolton, T.; Foudas, C.; Lefmann, W.C.; Leung, W.C.; Mishra, S.R.; Oltman, E.; Quintas, P.Z.; Rabinowitz, S.A.; Sciulli, F.J.; Seligman, W.G.; Shaevitz, M.H. (Columbia University, New York, New York 10027 (United States)); Merritt, F.S.; Oreglia, M.J.; Schumm, B.A. (University of Chicago, Chicago, Illinois 60637 (United States)); Bernstein, R.H.; Borcherding, F.; Fisk, H.E.; Lamm, M.J.; Marsh, W.; Merritt, K.W.B.; Schellman, H.M.; Yovanovitch, D.D. (Fermilab, Batavia, Illinois 60510 (United States)); Bodek, A.; Budd, H.S.; de Barbaro, P.; Sakumoto, W.K. (University of Rochester, Rochester, New York 14627 (United States)); Kinnel, T.; Sandler, P.H.; Smith, W.H. (University of Wisconsin Madison, Wisconsin 53706 (United States))

    1994-05-30

    We report a precise measurement of the weak mixing angle from the ratio of neutral current to charged current inclusive cross sections in deep-inelastic neutrino-nucleon scattering. The data were gathered at the CCFR neutrino detector in the Fermilab quadrupole-triplet beam, with neutrino energies up to 600 GeV. Using the on-shell definition, sin[sup 2][theta][sub [ital W

  9. Towards neutrino transport with flavor mixing in supernovae: the Liouville operator

    CERN Document Server

    Cardall, Christian Y

    2009-01-01

    The calculation of neutrino decoupling from nuclear matter requires a transport formalism capable of handling both collisions and flavor mixing. The first steps towards such a formalism are the construction of neutrino and antineutrino "distribution matrices," and a determination of the Liouville equations they satisfy in the noninteracting case. These steps are accomplished through study of a Wigner-transformed "density function," the mean value of paired neutrino quantum field operators.

  10. W. K. H. Panofsky Prize: The Road to Neutrino Mixing Angle θ13

    Science.gov (United States)

    Luk, Kam-Biu

    2014-03-01

    A series of solar, atmospheric, accelerator and reactor neutrino experiments have observed transformations of one type of neutrino to another type. This intriguing phenomenon called neutrino oscillation was predicted by Pontecorvo, Maki, Nakagawa and Sakata. It is due to the fact that the three flavors of neutrinos observed in laboratories are mixtures of three neutrino mass eigenstates. Neutrino mixing is described by a set of three mixing angles and a CP-violating phase. The smallest angle, θ13, was unknown until 2012. Knowing the value of θ13 is essential. Besides being a fundamental parameter of nature, knowing its value will improve our understanding of neutrino mixing, provide guidance for building theoretical models and define the future program of neutrino oscillation experiments. In this talk, the experimental development that led to the recent discovery of a new θ13-driven neutrino oscillation will be presented. Work was supported by the US Department of Energy, Office of High Energy Physics, contract DE-AC02-05CH11231.

  11. Measurement of Day and Night Neutrino Energy Spectra at SNO and Constraints on Neutrino Mixing Parameters

    CERN Document Server

    Ahmad, Q R; Andersen, T C; Anglin, J D; Barton, J C; Beier, E W; Bercovitch, M; Bigu, J; Biller, S D; Black, R A; Blevis, I; Boardman, R J; Boger, J; Bonvin, E; Boulay, M G; Bowler, M G; Bowles, T J; Brice, S J; Browne, M C; Bullard, T V; Buhler, G; Cameron, J; Chan, Y D; Chen, H H; Chen, M; Chen, X; Cleveland, B T; Clifford, E T H; Cowan, J H M; Cowen, D F; Cox, G A; Dai, X; Dalnoki-Veress, F; Davidson, W F; Doe, P J; Doucas, G; Dragowsky, M R; Duba, C A; Duncan, F A; Dunford, M; Dunmore, J A; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Ferraris, A P; Ford, R J; Formaggio, J A; Fowler, M M; Frame, K; Frank, E D; Frati, W; Gagnon, N; Germani, J V; Gil, S; Graham, K; Grant, D R; Hahn, R L; Hallin, A L; Hallman, E D; Hamer, A S; Hamian, A A; Handler, W B; Haq, R U; Hargrove, C K; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Hepburn, J D; Heron, H; Hewett, J L; Hime, A; Howe, M; Hykawy, J G; Isaac, M C P; Jagam, P; Jelley, N A; Jillings, C; Jonkmans, G; Kazkaz, K; Keener, P T; Klein, J R; Knox, A B; Komar, R J; Kouzes, R; Kutter, T; Kyba, C C M; Law, J; Lawson, I T; Lay, M; Lee, H W; Lesko, K T; Leslie, J R; Levine, I; Locke, W; Luoma, S; Lyon, J; Majerus, S; Mak, H B; Maneira, J; Manor, J; Marino, A D; McCauley, N; McDonald, A B; McDonald, D S; McFarlane, K; McGregor, G; Meijer-Drees, R; Miin, C; Miller, G G; Milton, G; Moffat, B A; Moorhead, M E; Nally, C W; Neubauer, M S; Newcomer, F M; Ng, H S; Noble, A J; Norman, E B; Novikov, V M; O'Neill, M; Okada, C E; Ollerhead, R W; Omori, Mamoru; Orrell, J L; Oser, S M; Poon, A W P; Radcliffe, T J; Roberge, A; Robertson, B C; Robertson, R G H; Rosendahl, S S E; Rowley, J K; Rusu, V L; Saettler, E; Schaffer, K K; Schwendener, M H; Schülke, A; Seifert, H; Shatkay, M; Simpson, J J; Sims, C J; Sinclair, D; Skensved, P; Smith, A R; Smith, M W E; Spreitzer, T; Starinsky, N; Steiger, T D; Stokstad, R G; Stonehill, L C; Storey, R S; Sur, B; Tafirout, R; Tagg, N; Tanner, N W; Taplin, R K; Thorman, M; Thornewell, P M; Trent, P T; Tserkovnyak, Y; Van Berg, R; Van de Water, R G; Virtue, C J; Waltham, C E; Wang, J X; Wark, D L; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wittich, P; Wouters, J M; Yeh, M

    2002-01-01

    The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted $^8$B spectrum, the night minus day rate is $14.0% \\pm 6.3% ^{+1.5}_{-1.4}%$ of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the $\

  12. Flavor Democracy and Type-II Seesaw Realization of Bilarge Neutrino Mixing

    CERN Document Server

    Rodejohann, W; Rodejohann, Werner; Xing, Zhi-zhong

    2004-01-01

    We generalize the democratic neutrino mixing Ansatz by incorporating the type-II seesaw mechanism with S(3) flavor symmetry. We find that bilarge neutrino mixing can naturally appear if the flavor democracy contribution is strongly suppressed due to significant cancellation between the conventional seesaw and triplet mass terms. Explicit S(3) symmetry breaking yields successful neutrino phenomenology and various testable correlations between the neutrino mass and mixing parameters. Among the results are a normal neutrino mass ordering, $0.005 \\le |U_{e3}| \\le 0.057$, $1 - \\sin^2 2\\theta_{23} \\ge 0.005$, positive $J_{\\rm CP}$ and moderate cancellation in the effective mass of the neutrinoless double beta decay.

  13. Robust flavor equalization of cosmic neutrino flux by quasi bi-maximal mixing

    CERN Document Server

    Ahluwalia, D V; Adunas, G Z

    2000-01-01

    The observed L/E flatness of the electron-like event ratio in the Super-Kamiokande atmospheric neutrino data strongly favors a quasi bi-maximal mixing matrix. This situation is here exploited to understand the numerical results of Yasuda on the high energy cosmic neutrino flux. In agreement with the Yasuda result, we analytically show how the quasi bi-maximal neutrino mixing makes the high energy cosmic neutrino flux at the AGN/GRB source, F(nu_e):F(nu_mu):F(nu_tau) approx 1:2:0, oscillates to, F(nu_e):F(nu_\\mu):F(nu_tau)approx 1:1:1. Apart from its independence from the underlying mass-squared differences, we find that this prediction is quite robust in that it is independent of the mixing angle responsible for the resolution of the solar/LSND neutrino anomaly.

  14. Oscillation and Mixing Among the Three Neutrino Flavors

    CERN Document Server

    Weiler, Thomas J

    2013-01-01

    With the educated, interested non-specialist as the target audience, we overview what is known and not known about contemporary neutrino physics. Theory tells us that neutrinos are the second-most common particle in the Universe, behind only the quanta of radiation called photons. Almost a trillion neutrinos per second enter each human eyeball, and yet we do not see them; these neutrinos, in roughly equal numbers, are emanations from our Sun and relics of the hot "big bang" era of the early Universe. Much of what we know about neutrinos, and hope to learn in the future, is derived from a unique feature of neutrinos -- "oscillation" among neutrino "flavor" types. An initial neutrino flavor will in general oscillate into another flavor as the neutrino propagates in space and time. Oscillations are a quantum mechanical phenomenon. One of the wonders of neutrinos is that their quantum mechanics may be observed over large distances, even astronomically large. We begin this article with neutrino phenomenology in te...

  15. Search for the sterile neutrino mixing with the ICAL detector at INO

    CERN Document Server

    Behera, S P; Choubey, Sandhya; Datar, V M; Mishra, D K; Mohanty, A K

    2016-01-01

    The study has been carried out on the prospects of probing the sterile neutrino mixing with the magnetized Iron CALorimeter (ICAL) at the India-based Neutrino Observatory (INO), using atmospheric neutrinos as a source. The so-called 3~$+$~1 scenario is considered for active-sterile neutrino mixing and lead to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed using the neutrino event generator NUANCE, modified for ICAL, and folded with the detector resolutions obtained by the INO collaboration from a full GEANT4 based detector simulation. A comparison has been made between the results obtained from the analysis considering only the energy and zenith angle of the muon and combined with the hadron energy due to the neutrino induced event. A small improvement has been observed with the addition of the hadron information to the muon. In the analysis we consider neutrinos coming from all zenith angles and the Earth matter effects are also included. The inclusi...

  16. Neutrino mixing and CP violation phases in Zee-Babu model

    CERN Document Server

    Van Vien, Vo; Thu, Pham Ngoc

    2014-01-01

    We show that the neutrino mass matrix of the Zee-Babu model is able to fit the most recent data on neutrino masses and mixing with large $\\theta_{13}$ and provides %the values of the Dirac and Majorana CP violation phases. For the normal hierarchy, the Majorana phases ($\\al_{2 1}, \\al_{3 1}$) are equal to zero, while for the inverted pattern, one phase ($\\al_{3 1}$) takes the value $2 \\pi$. The Dirac phase ($\\de$) is predicted to either $0$ or $\\pi$. The effective mass governing neutrinoless double beta decay and the sum of neutrino masses are consistent with the recent analysis. The model gives some regions of the parameters of neutrino mixing angles in both normal and inverted neutrino mass hierarchy.

  17. Neutrino mixing: from the broken μ-τ symmetry to the broken Friedberg–Lee symmetry

    International Nuclear Information System (INIS)

    I argue that the observed flavor structures of leptons and quarks might imply the existence of certain flavor symmetries. The latter should be a good starting point to build realistic models towards deeper understanding of the fermion mass spectra and flavor mixing patterns. The μ-τ permutation symmetry serves for such an example to interpret the almost maximal atmospheric neutrino mixing angle (θ23 ~ 45°) and the strongly suppressed CHOOZ neutrino mixing angle (θ13 < 10°). In this talk I like to highlight a new kind of flavor symmetry, the Friedberg–Lee symmetry, for the effective Majorana neutrino mass operator. Luo and I have shown that this symmetry can be broken in an oblique way, such that the lightest neutrino remains massless but an experimentally-favored neutrino mixing pattern is achievable. We get a novel prediction for θ13 in the CP-conserving case: sinθ13 = tanθ12|(1 - tanθ23)/(1 + tanθ23)|. Our scenario can simply be generalized to accommodate CP violation and be combined with the seesaw mechanism. Finally I stress the importance of probing possible effects of μ-τ symmetry breaking either in terrestrial neutrino oscillation experiments or with ultrahigh-energy cosmic neutrino telescopes. (author)

  18. Inconsistence of super-luminal Opera neutrino speed with SN1987A neutrinos burst and with flavor neutrino mixing

    CERN Document Server

    Fargion, D

    2011-01-01

    Recent news from Cern Opera experiment seem to hint for a muon neutrino faster than light, maybe tachyon in nature. If all neutrino are just tachyon their arrival (at 17 MeV) will be even much faster than 17 GeV Opera neutrino, nearly 2.5 times faster than c, coming back nearly 100000 years ago. If all the neutrino velocity, independently on their energy, were frozen at a Opera speed 2.5 10^{-5} times faster than c, than Supernova 1987A had not to be observed (as it is well known to be) on February 23th 1987, but just 4.2 years before. Possibly in late 1982 early 1983, miraculously hidden in oldest IMB records. In such tuned new physics no explanation will be on the same neutrino burst found on February 23 1987. A more consistent scenario is the one where electron neutrinos (and antineutrino) fly at velocity c, while muon neutrino are super-luminal: than SN1987A electron neutrino may be in agreement with observed signals; nevertheless even in this ideal scenario one should also find a coexisting precursor neu...

  19. 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.

  20. Self-induced neutrino flavor conversion without flavor mixing

    CERN Document Server

    Chakraborty, Sovan; Izaguirre, Ignacio; Raffelt, Georg

    2016-01-01

    Neutrino-neutrino refraction in dense media can cause self-induced flavor conversion triggered by collective run-away modes of the interacting flavor oscillators. The growth rates were usually found to be of order a typical vacuum oscillation frequency $\\Delta m^2/2E$. However, even in the simple case of a $\

  1. What can we learn from high precision measurements of neutrino mixing angles?

    Indian Academy of Sciences (India)

    R N Mohapatra

    2004-12-01

    Many experiments are being planned to measure the neutrino mixing angles more precisely. In this note, the theoretical significance of a high precision measurement of these parameters is discussed. It is emphasized that they can provide crucial information about different ways to understand the origin of large atmospheric neutrino mixing and move us closer towards determining the neutrino mass matrix. They may also be able to throw light on the question of lepton–quark unification as well as the existence of any leptonic symmetries. For instance if exact ↔ symmetry in the neutrino mass matrix is assumed to be the reason for maximal - mixing, one gets 13 = 0 and 13 ≃ $\\sqrt{ m^{2}_{\\odot} / m^{2}_{{\\text{A}}}$ or 13 ≃ $ m^{2}_{\\odot} / m^{2}_{{\\text{A}}}$ can provide information about the way the ↔ symmetry breaking manifests in the case of normal hierarchy.

  2. Precise Measurement of the Neutrino Mixing Parameter \\theta_{23} from Muon Neutrino Disappearance in an Off-axis Beam

    CERN Document Server

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

    2014-01-01

    New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter theta_{23}. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57 x 10^{20} protons on target, T2K has fit the energy-dependent nu_mu oscillation probability to determine oscillation parameters. Marginalizing over the values of other oscillation parameters yields sin^2 (theta_{23}) = 0.514 +0.055/-0.056 (0.511 +- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m^2_{32} = 2.51 +- 0.10 x 10^{-3} eV^2/c^4 (inverted hierarchy: Delta m^2_{13} = 2.48 +- 0.10 x 10^{-3} eV^2/c^4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

  3. Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam.

    Science.gov (United States)

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

    2014-05-01

    New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty. PMID:24856687

  4. Neutrino masses and mixing with seesaw mechanism and universal breaking of extended democracy

    CERN Document Server

    Akhmedov, E K; Joaquim, F R; Silva-Marcos, Joaquim I

    2001-01-01

    In the framework of a minimal extension of the SM, where the only additional fields are three right-handed neutrinos, we suggest that the charged lepton, the Dirac neutrino and the right-handed Majorana neutrino mass matrices are all, to leading approximation, proportional to the democratic matrix. With the further assumption that the breaking of this extended democracy is universal for all leptonic mass matrices, a large mixing in the 2-3 sector can be obtained and is linked to the seesaw mechanism, together with the existence of a strong hierarchy in the masses of right-handed neutrinos. A good fit to all solar and atmospheric neutrino data is obtained.

  5. 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.

  6. 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.

  7. 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.

  8. Neutrino oscillations

    International Nuclear Information System (INIS)

    Lecture notes on neutrino oscillations are given, including some background about neutrino mixing and masses, descriptions of flavour oscillations and experimental attempts to detect them, matter effects and neutrino-antineutrino oscillations. (U.K.)

  9. Reactor anti-neutrinos: measurement of the θ13 leptonic mixing angle and search for potential sterile neutrinos

    International Nuclear Information System (INIS)

    The Double Chooz experiment aims to measure the θ13 mixing angle through the disappearance -induced by the oscillation phenomenon - of anti-neutrinos produced by the Chooz nuclear reactors. In order to reduce systematic uncertainties, the experiment relies on the relative comparison of detected signals in two identical liquid scintillator detectors. The near one, giving the normalization of the emitted flux, is currently being built and will be delivered in spring 2014. The far detector, sensitive to θ13, is located at about one kilometer and is taking data since 2011. In this first phase of the experiment, the far detector data are compared to a prediction of the emitted neutrino flux to estimate θ13. In this thesis, the Double Chooz experiment and its analysis are presented, especially the background studies and the rejection of parasitic signals due to light emitted by photo-multipliers. Neutron fluxes between the different detector volumes impact the definition of the fiducial volume of neutrino interactions and the efficiency of detection. Detailed studies of these effects are presented. As part of the Double Chooz experiment, studies were performed to improve the prediction of neutrino flux emitted by reactors. This work revealed a deficit of observed neutrino rates in the short baseline experiments of last decades. This deficit could be explained by an oscillation to a sterile state. The Stereo project aims to observe a typical signature of oscillations: the distortion of neutrino spectra both in energy and baseline. This thesis presents the detector concept and simulations as well as sensitivity studies. Background sources and the foreseen shielding are also discussed. (author)

  10. Mixed cold-hot dark matter model with several massive neutrino types

    CERN Document Server

    Pogosyan, D; Pogosyan, Dmitri; Starobinsky, Alexei

    1995-01-01

    Mixed cold-hot dark matter cosmological models (CHDM) with \\Omega_{tot}=1, approximately flat initial spectrum of adiabatic perturbations and 1, 2 or 3 types of massive neutrinos are compared and tested using recent observational data. The models with 2 or 3 neutrino types of equal mass permit as the best fit larger values of both the Hubble constant (H_0\\le 60 for 2 types, H_0\\le 65 for 3 types) and the total \\Omega_{\

  11. A further study of the Frampton-Glashow-Yanagida model for neutrino masses, flavor mixing and baryon number asymmetry

    OpenAIRE

    Zhang, Jue; Zhou, Shun

    2015-01-01

    In light of the latest neutrino oscillation data, we revisit the minimal scenario of type-I seesaw model, in which only two heavy right-handed Majorana neutrinos are introduced to account for both tiny neutrino masses and the baryon number asymmetry in our Universe. In this framework, we carry out a systematic study of the Frampton-Glashow-Yanagida ansatz by taking into account the renormalization-group running of neutrino mixing parameters and the flavor effects in leptogenesis. We demonstra...

  12. 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.

  13. A massless neutrino and lepton mixing patterns from finite discrete subgroups of U(3)

    International Nuclear Information System (INIS)

    Finite discrete subgroups of U(3) as possible flavour symmetries Gf for a massless neutrino with predictive mixing angles are studied. This is done by assuming that a residual symmetry Sν appropriate for describing a massless neutrino is contained in Gf. It is shown that all the groups Gf admitting three dimensional faithful irreducible representation and generated from a specific set of 3×3 matrices imply only one of the three flavour compositions for the massless state namely, unmixed, maximally mixed with equal probabilities and bimaximally mixed with probabilities (0,1/2,1/2) and their permutations. This result holds irrespective of the order of Gf and the choice of Sν within it. All of these lead to unfavorable leading order prediction for the solar mixing angle. Neutrino mixing pattern is then numerically investigated in case of subgroups of U(3) with order less than 512 and it is found that only one of these can lead to a massless neutrino and leading order predictions for all the mixing angles close to their experimental values. Ways to correct for the solar angle prediction are proposed and two concrete examples giving the observed mixing pattern are discussed

  14. Neutrino mixing from the double tetrahedral group $T^{\\prime}$

    CERN Document Server

    Aranda, Alfredo

    2007-01-01

    It is shown that it is possible to create successful models of flavor for both quarks and leptons using the discrete non-abelian group $T^{\\prime}$ by itself. Two simple realizations are presented that can be used as the starting point for more general scenarios. In addition to the Minimal Supersymmetric Standard Model particle content, the models include three generations of right handed neutrinos and four scalar flavon fields. Three of the flavons are needed in the quark and charged lepton sector of the models and the fourth flavon participates only in the neutrino sector.

  15. The strongest bounds on active-sterile neutrino mixing after Planck data

    International Nuclear Information System (INIS)

    Light sterile neutrinos can be excited by oscillations with active neutrinos in the early universe. Their properties can be constrained by their contribution as extra-radiation, parameterized in terms of the effective number of neutrino species Neff, and to the universe energy density today Ωνh2. Both these parameters have been measured to quite a good precision by the Planck satellite experiment. We use this result to update the bounds on the parameter space of (3+1) sterile neutrino scenarios, with an active-sterile neutrino mass squared splitting in the range (10−5–102) eV2. We consider both normal and inverted mass orderings for the active and sterile states. For the first time we take into account the possibility of two non-vanishing active-sterile mixing angles. We find that the bounds are more stringent than those obtained in laboratory experiments. This leads to a strong tension with the short-baseline hints of light sterile neutrinos. In order to relieve this disagreement, modifications of the standard cosmological scenario, e.g. large primordial neutrino asymmetries, are required

  16. The strongest bounds on active-sterile neutrino mixing after Planck data

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [II Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Mangano, Gianpiero [Istituto Nazionale di Fisica Nucleare – Sezione di Napoli, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Saviano, Ninetta, E-mail: ninetta.saviano@desy.de [II Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Istituto Nazionale di Fisica Nucleare – Sezione di Napoli, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Borriello, Enrico [II Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Giunti, Carlo [Department of Physics, University of Torino and INFN, Via P. Giuria 1, I-10125 Torino (Italy); Miele, Gennaro; Pisanti, Ofelia [Istituto Nazionale di Fisica Nucleare – Sezione di Napoli, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy)

    2013-10-07

    Light sterile neutrinos can be excited by oscillations with active neutrinos in the early universe. Their properties can be constrained by their contribution as extra-radiation, parameterized in terms of the effective number of neutrino species N{sub eff}, and to the universe energy density today Ω{sub ν}h{sup 2}. Both these parameters have been measured to quite a good precision by the Planck satellite experiment. We use this result to update the bounds on the parameter space of (3+1) sterile neutrino scenarios, with an active-sterile neutrino mass squared splitting in the range (10{sup −5}–10{sup 2}) eV{sup 2}. We consider both normal and inverted mass orderings for the active and sterile states. For the first time we take into account the possibility of two non-vanishing active-sterile mixing angles. We find that the bounds are more stringent than those obtained in laboratory experiments. This leads to a strong tension with the short-baseline hints of light sterile neutrinos. In order to relieve this disagreement, modifications of the standard cosmological scenario, e.g. large primordial neutrino asymmetries, are required.

  17. Quantum effects for the neutrino mixing matrix in the democratic-type model

    CERN Document Server

    Miura, T; Yoshimura, M; Miura, Takahiro; Takasugi, Eiichi; Yoshimura, Masaki

    2000-01-01

    We investigate the quantum effects for the democratic-type neutrino mass matrix given at the right-handed neutrino mass scale $m_R$ in order to see (i) whether $\\theta_{23}=-\\pi/4$ predicted by the model is stable to explain the atmospheric neutrino anomaly, (ii) how $\\theta_{12}$ and $\\theta_{13}$ behave, and (iii) whether the predicted Dirac CP phase $\\delta$ keeps maximal size, at the weak scale $m_Z$. We find that, for the (inversely) hierarchical mass spectrum with $m_1\\sim m_2$, $\\theta_{23}$ and $\\theta_{13}$ are stable, while $\\theta_{12}$ is not so, which leads to the possibility that the solar neutrino mixing angle can become small at $m_Z$ even if it is taken large at $m_R$, or vice versa. We also show that $\\delta$ keeps almost maximal for the above mass spectrum, and our model can give the large CP violation effect in the future neutrino oscillation experiments if the solar neutrino puzzle is explained by the large mixing angle MSW solution.

  18. 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.

  19. A Mechanism for Ordinary-Sterile Neutrino Mixing

    OpenAIRE

    Langacker, Paul

    1998-01-01

    Efficient oscillations between ordinary (active) and sterile neutrinos can occur only if Dirac and Majorana mass terms exist which are both small and comparable. It is shown that this can occur naturally in a class of string models, in which higher-dimensional operators in the superpotential lead to an intermediate scale expectation value for a scalar field and to suppressed Dirac and Majorana fermion masses.

  20. Bimaximal neutrino mixing and weak complementarity with S4 discrete symmetry

    CERN Document Server

    Merlo, Luca

    2009-01-01

    The neutrino oscillation data are well explained by the tri-bimaximal pattern. Recently a paper appeared showing that also the bimaximal pattern could be a very good starting point in order to describe the lepton mixing. In this paper I review both the flavour structures and then I present an explicit model based on the discrete symmetry group S4.

  1. 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

  2. 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.

  3. Neutrino

    CERN Document Server

    Close, Frank

    2010-01-01

    What are neutrinos? Why does nature need them? What use are they?Neutrinos are perhaps the most enigmatic particles in the universe. Formed in certain radioactive decays, they pass through most matter with ease. These tiny, ghostly particles are formed in millions in the Sun and pass through us constantly. For a long time they were thought to be massless, and passing as they do like ghosts they were not regarded as significant. Now we know they have a very small mass, and there are strong indications that they are very important indeed. It is speculated thata heavy form of neutrino, that is bo

  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. Very Long Baseline Neutrino Oscillation Experiments for Precise Measurements of Mixing Parameters and CP Violating Effects

    CERN Document Server

    Diwan, M V; Gallardo, J; Kahn, S; Kirk, H; Marciano, W; Morse, W; Parsa, Z; Samios, Nicholas P; Semertzidis, Y K; Viren, B M; Weng, W; Yamin, P; Frati, W; Lande, K; Mann, A K; Berg, R V; Wildenhain, P S; Klein, J R; Mocioiu, I; Shrock, R E; McDonald, K T

    2003-01-01

    We analyze the prospects of a feasible, very long baseline neutrino oscillation experiment consisting of a conventional horn produced low energy wide band beam and a detector of 500 kT fiducial mass with modest requirements on event recognition and resolution. Such an experiment is intended primarily to measure CP violating effects in the neutrino sector for 3-generation mixing. We analyze the sensitivity of such an experiment. We conclude that this experiment will allow determination of the CP parameter $\\delta_{CP}$, if the currently unknown mixing parameter $\\sin ^2 2 \\theta_{13} \\geq 0.01$, a value about 10 times lower than the present experimental upper limit. In addition to $\\theta_{13}$ and $\\delta_{CP}$, the experiment has great potential for precise measurements of most other parameters in the neutrino mixing matrix including $\\Delta m^2_{32}$, $\\sin^2 2\\theta_{23}$, $\\Delta m^2_{21}\\times \\sin^2 2 \\theta_{12}$, and the mass ordering of neutrinos through the observation of the matter effect in the $\\...

  6. Sterile neutrinos?

    OpenAIRE

    Bilenky, S. M.; Giunti, C.

    1999-01-01

    The notion of sterile neutrinos is discussed. The schemes of mixing of four massive neutrinos, which imply the existence of sterile neutrinos, are briefly considered. Several model independent methods that allow to reveal possible transitions of solar neutrinos into sterile states are presented.

  7. A New Variant of $\\mu$\\,--\\,$\\tau$ Symmetry for One Generic Neutrino Mixing Angle: Analytical Study

    CERN Document Server

    Lashin, E I; Hamzaoui, C; Nasri, S

    2016-01-01

    We find a realization of the $Z_2$-symmetry behind the $\\mu-\\tau$ universality in the neutrino mass matrix able to impose a generic smallest mixing angle, in contrast to a zero-value predicted by the usual form of the $\\mu-\\tau$ symmetry. We extend this symmetry for the lepton sector within type-I seesaw scenario, and show it can accommodate the mixing angles, the mass hierarchies and the lepton asymmetry in the universe. We then study the effects of perturbing the specific form of the neutrino mass matrix imposed by the symmetry and compute the resulting mixing and mass spectrum. We trace back this "low-scale" perturbation to a "high-scale" perturbation, and find realizations of this latter one arising from exact symmetries with an enriched matter content.

  8. Determination of the third neutrino-mixing angle θ13 and its implications

    Science.gov (United States)

    Roy, D. P.

    2013-05-01

    Until 2010 we had three unknown parameters of neutrino oscillation—the third mixing angle θ13, the sign of the larger mass difference Δm312 and the CP violating phase δ. Thanks to a number of consistent experimental results since then, culminating in the recent Daya Bay reactor neutrino data, we now have a definitive determination of θ13. Moreover its measured value, sin22θ13 ≈ 0.1, is close to its earlier upper limit. This has promising implications for the determination of the two remaining unknown parameters from the present and proposed accelerator neutrino experiments in the foreseeable future. This article presents a pedagogical review of these profound developments for the wider community of young physicists including university students.

  9. Determination of the Third Neutrino-Mixing Angle {\\theta}_(13) and its Implications

    CERN Document Server

    Roy, D P

    2013-01-01

    Till 2010 we had three unknown parameters of neutrino oscillation: the third mixing angle {\\theta}_(13), the sign of the larger mass difference {\\Delta}m^(2)_(31) and the CP violating phase {\\delta}. Thanks to a number of consistent experimental results since then, culminating in the recent Daya Bay reactor neutrino data, we have a definitive determination of {\\theta}_(13) now. Moreover its measured value, sin^(2)_(2 {\\theta}_(13)) = 0.1, is close to its earlier upper limit. This has promising implications for the determination of the two remaining unknown parameters from the present and proposed accelerator neutrino experiments in the foreseeable future. This article presents a pedagogical review of these profound developments for the wider community of young physicists including university students.

  10. 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.

  11. 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.

  12. Implications of Recent Data on Neutrino Mixing and Lepton Flavour Violating Decays for the Zee Model

    CERN Document Server

    He, Xiao-Gang

    2011-01-01

    We study implications of recent data on neutrino mixing from T2K, MINOS, Double Chooz and $\\mu \\to e \\gamma$ from MEG for the Zee model. The simplest version of this model has been shown to be ruled out by experimental data some time ago. The general Zee model is still consistent with recent data. We demonstrate this with a constrained Zee model based on naturalness consideration. In this constrained model, only inverted mass hierarchy for neutrino masses is allowed, and $\\theta_{13}$ must be non-zero in order to have correct ratio for neutrino mass-squared differences and for mixing in solar and atmospherical neutrino oscillations. The best fit value of our model for $\\theta_{13}$ is $8.91\\deg$ from T2K and MINOS data, very close to the central value obtained by Double Chooz experiment. There are solutions with non-zero CP violation with the Jarlskog parameter predicted in the range $\\pm 0.039$, $\\pm 0.044$ and $\\pm 0.048$ respectively for a 1$\\sigma$, 2$\\sigma$ and 3$\\sigma$ ranges of other input parameters...

  13. Lepton Flavor Mixing Pattern and Neutrino Mass Matrix after the Daya Bay Experiment

    CERN Document Server

    Zhou, Shun

    2012-01-01

    The Daya Bay Collaboration has recently observed neutrino oscillations in the nu_e-bar -> nu_e-bar disappearance channel, indicating that sin^2 theta_13 = 0.024 +(-) 0.005 (1 sigma) and theta_13 = 0 is already excluded at the 5.2 sigma confidence level. Now three neutrino mixing angles have been measured to a good degree of accuracy (theta_12 ~ 34^\\circ, theta_23 ~ 45^\\circ and theta_13 ~ 9^\\circ). Motivated by these experimental results, we propose a novel lepton flavor mixing pattern, which predicts sin^2 theta_23 = 1/2, sin^2 theta_12 = (2+\\sqrt{3})/(10+\\sqrt{3}) ~ 0.318 and sin^2 theta_13 = (2-\\sqrt{3})/12 ~ 0.022, together with a maximal CP-violating phase delta = 90^\\circ. The leptonic CP violation characterized by the Jarlskog invariant {\\cal J} = \\sqrt{6}/72 ~ 3.4 % is promising to be measured in the future long-baseline neutrino oscillation experiments. Furthermore, we point out that a generalized version of mu-tau symmetry may exist in the neutrino sector and can give rise to the aforementioned mixi...

  14. Lepton family symmetries for neutrino masses and mixing

    Indian Academy of Sciences (India)

    Ernest Ma

    2006-11-01

    I review some of the recent progress (up to December 2005) in applying non-Abelian discrete symmetries to the family structure of leptons, with particular emphasis on the tribimaximal mixing ansatz of Harrison, Perkins and Scott.

  15. 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...

  16. Neutrino mixing and masses in SO(10) GUTs with hidden sector and flavor symmetries

    Science.gov (United States)

    Chu, Xiaoyong; Smirnov, Alexei Yu.

    2016-05-01

    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 ˜ V CKM † 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 × 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 assignments. We formulate additional conditions which lead to U 0 ˜ U TBM or U BM. They include (i) equality (in general, proportionality) of the singlet flavons couplings, (ii) equality of their VEVs; (iii) correlation between VEVs of singlets and triplet, (iv) certain VEV alignment of flavon triplet(s). These features can follow from additional symmetries or be remnants of further unification. Phenomenologically viable schemes with minimal flavon content and minimal number of couplings are constructed.

  17. Constructing the large mixing angle MNS matrix in see-saw models with right-handed neutrino dominance

    Science.gov (United States)

    King, Stephen F.

    2002-09-01

    Recent SNO results strongly favour the large mixing angle (LMA) MSW solar solution. We argue that there are only two technically natural low energy neutrino mass matrix structures consistent with the LMA MSW solution, corresponding to either a hierarchy or an inverted hierarchy with pseudo-Dirac neutrinos. We construct the MNS matrix to leading order in the small angle θ13 including the neutrino and charged lepton mixing angles and phases, the latter playing a crucial rôle for allowing the inverted hierarchy case to be consistent with the LMA MSW solution. We then consider the see-saw mechanism with right-handed neutrino dominance and show how the successful neutrino mass matrix structures may be constructed with no tuning and with small radiative corrections, leading to a full, partial or inverted neutrino mass hierarchy. In each case we derive approximate analytic relations between the input see-saw parameters and the resulting neutrino masses, mixing angles and phases, which will provide a useful guide for unified model building. For the hierarchical cases the LMA MSW solution gives a soft lower bound |Ue3| gtrsim 0.1, just below the current CHOOZ limit. Both hierarchical and inverted hierarchical cases predict small ββ0ν with |mee| ~ 0.007 eV within the sensitivity of future proposals such as GENIUS. Successful leptogenesis is possible if the dominant right-handed neutrino is the heaviest one, but the leptogenesis phase is unrelated to the MNS phases.

  18. Neutrino Physics

    OpenAIRE

    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.

  19. The weak mixing angle from low energy neutrino measurements: a global update

    CERN Document Server

    Canas, B C; Miranda, O G; Tortola, M; Valle, J W F

    2016-01-01

    Taking into account recent theoretical and experimental inputs on reactor fluxes we reconsider the determination of the weak mixing angle from low energy experiments. We perform a global analysis to all available neutrino-electron scattering data from reactor antineutrino experiments, obtaining sin^2(theta_W) = 0.252 \\pm 0.030. We discuss the impact of the new theoretical prediction for the neutrino spectrum, the new measurement of the reactor antineutrino spectrum by the Daya Bay collaboration, as well as the effect of radiative corrections. We also reanalyze the measurements of the nu_e-e cross section at accelerator experiments including radiative corrections. By combining reactor and accelerator data we obtain an improved determination for the weak mixing angle, sin^2(theta_W) = 0.254 \\pm 0.024.

  20. Direct and semi-direct approaches to lepton mixing with a massless neutrino

    Science.gov (United States)

    King, Stephen F.; Ludl, Patrick Otto

    2016-06-01

    We discuss the possibility of enforcing a massless Majorana neutrino in the direct and semi-direct approaches to lepton mixing, in which the PMNS matrix is partly predicted by subgroups of a discrete family symmetry, extending previous group searches up to order 1535. We find a phenomenologically viable scheme for the semi-direct approach based on Q(648) which contains Δ(27) and the quaternion group as subgroups. This leads to novel predictions for the first column of the PMNS matrix corresponding to a normal neutrino mass hierarchy with m 1 = 0, and sum rules for the mixing angles and phase which are characterised by the solar angle being on the low side θ 12 ˜ 31° and the Dirac (oscillation) CP phase δ being either about ±45° or ±π.

  1. The weak mixing angle from low energy neutrino measurements: A global update

    Science.gov (United States)

    Cañas, B. C.; Garcés, E. A.; Miranda, O. G.; Tórtola, M.; Valle, J. W. F.

    2016-10-01

    Taking into account recent theoretical and experimental inputs on reactor fluxes we reconsider the determination of the weak mixing angle from low energy experiments. We perform a global analysis to all available neutrino-electron scattering data from reactor antineutrino experiments, obtaining sin2 ⁡θW = 0.252 ± 0.030. We discuss the impact of the new theoretical prediction for the neutrino spectrum, the new measurement of the reactor antineutrino spectrum by the Daya Bay collaboration, as well as the effect of radiative corrections. We also reanalyze the measurements of the νe - e cross section at accelerator experiments including radiative corrections. By combining reactor and accelerator data we obtain an improved determination for the weak mixing angle, sin2 ⁡θW = 0.254 ± 0.024.

  2. Direct and Semi-Direct Approaches to Lepton Mixing with a Massless Neutrino

    CERN Document Server

    King, Stephen F

    2016-01-01

    We discuss the possibility of enforcing a massless Majorana neutrino in the direct and semi-direct approaches to lepton mixing, in which the PMNS matrix is partly predicted by subgroups of a discrete family symmetry, extending previous group searches up to order 1535. We find a phenomenologically viable scheme for the semi-direct approach based on $Q(648)$ which contains $\\Delta(27)$ and the quaternion group as subgroups. This leads to novel predictions for the first column of the PMNS matrix corresponding to a normal neutrino mass hierarchy with $m_1=0$, and sum rules for the mixing angles and phase which are characterised by the solar angle being on the low side $\\theta_{12}\\sim 31^{\\circ}$ and the Dirac (oscillation) CP phase $\\delta$ being either about $\\pm 45^\\circ$ or $\\pm \\pi$.

  3. Neutrino Mixings and the S4 Discrete Flavour Symmetry

    CERN Document Server

    Bazzocchi, Federica

    2012-01-01

    Discrete non-Abelian Symmetries have been extensively used to reproduce the lepton mixings. In particular, the S4 group turned out to be suitable to describe predictive mixing patterns, such as the well-known Tri-Bimaximal and the Bimaximal schemes, which all represent possible first approximations of the experimental lepton mixing matrix. We review the main application of the S4 discrete group as a flavour symmetry, first dealing with the formalism and later with the phenomenological implications. In particular, we summarize the main features of flavour models based on S4, commenting on their ability in reproducing a reactor angle in agreement with the recent data and on their predictions for lepton flavour violating transitions.

  4. Neutrino emissivity in the quark-hadron mixed phase of neutron stars

    International Nuclear Information System (INIS)

    Numerous theoretical studies using various equation of state models have shown that quark matter may exist at the extreme densities in the cores of high-mass neutron stars. It has also been shown that a phase transition from hadronic matter to quark matter would result in an extended mixed phase region that would segregate phases by net charge to minimize the total energy of the phase, leading to the formation of a crystalline lattice. The existence of quark matter in the core of a neutron star may have significant consequences for its thermal evolution, which for thousands of years is facilitated primarily by neutrino emission. In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the core. To this end we calculate the equation of state using the relativistic mean-field approximation to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures (

  5. Improved measurements of the neutrino mixing angle $\\theta_{13}$ with the Double Chooz detector

    CERN Document Server

    Abe, Y; Barriere, J C; Baussan, E; Bekman, I; Bergevin, M; Bezerra, T J C; Bezrukov, L; Blucher, E; Buck, C; Busenitz, J; Cabrera, A; Caden, E; Camilleri, L; Carr, R; Cerrada, M; Chang, P -J; Chauveau, E; Chimenti, P; Collin, A P; Conover, E; Conrad, J M; Crespo-Anadón, J I; Crum, K; Cucoanes, A S; Damon, E; Dawson, J V; Dietrich, D; Djurcic, Z; Dracos, M; Elnimr, M; Etenko, A; Fallot, M; von Feilitzsch, F; Felde, J; Fernandes, S M; Fischer, V; Franco, D; Franke, M; Furuta, H; Gil-Botella, I; Giot, L; Göger-Neff, M; Gonzalez, L F G; Goodenough, L; Goodman, M C; Grant, C; Haag, N; Hara, T; Haser, J; Hofmann, M; Horton-Smith, G A; Hourlier, A; Ishitsuka, M; Jochum, J; Jollet, C; Kaether, F; Kalousis, L N; Kamyshkov, Y; Kaplan, D M; Kawasaki, T; Kemp, E; de Kerret, H; Kryn, D; Kuze, M; Lachenmaier, T; Lane, C E; Lasserre, T; Letourneau, A; Lhuillier, D; Lima, H P; Lindner, M; López-Castaño, J M; LoSecco, J M; Lubsandorzhiev, B; Lucht, S; Maeda, J; Mariani, C; Maricic, J; Martino, J; Matsubara, T; Mention, G; Meregaglia, A; Miletic, T; Milincic, R; Minotti, A; Nagasaka, Y; Nikitenko, Y; Novella, P; Oberauer, L; Obolensky, M; Onillon, A; Osborn, A; Palomares, C; Pepe, I M; Perasso, S; Pfahler, P; Porta, A; Pronost, G; Reichenbacher, J; Reinhold, B; Röhling, M; Roncin, R; Roth, S; Rybolt, B; Sakamoto, Y; Santorelli, R; Schilithz, A C; Schönert, S; Schoppmann, S; Shaevitz, M H; Sharankova, R; Shimojima, S; Shrestha, D; Sibille, V; Sinev, V; Skorokhvatov, M; Smith, E; Spitz, J; Stahl, A; Stancu, I; Stokes, L F F; Strait, M; Stüken, A; Suekane, F; Sukhotin, S; Sumiyoshi, T; Sun, Y; Svoboda, R; Terao, K; Tonazzo, A; Thi, H H Trinh; Valdiviesso, G; Vassilopoulos, N; Veyssiere, C; Vivier, M; Wagner, S; Watanabe, H; Wiebusch, C; Winslow, L; Wurm, M; Yang, G; Yermia, F; Zimmer, V

    2014-01-01

    The Double Chooz experiment presents improved measurements of the neutrino mixing angle $\\theta_{13}$ using the data collected in 467.90 live days from a detector positioned at an average distance of 1050 m from two reactor cores at the Chooz nuclear power plant. Several novel techniques have been developed to achieve significant reductions of the backgrounds and systematic uncertainties with respect to previous publications, whereas the efficiency of the $\\bar\

  6. Neutrino emissivity in the quark-hadron mixed phase of neutron stars

    Science.gov (United States)

    Spinella, William M.; Weber, Fridolin; Contrera, Gustavo A.; Orsaria, Milva G.

    2016-03-01

    Numerous theoretical studies using various equation of state models have shown that quark matter may exist at the extreme densities in the cores of high-mass neutron stars. It has also been shown that a phase transition from hadronic matter to quark matter would result in an extended mixed phase region that would segregate phases by net charge to minimize the total energy of the phase, leading to the formation of a crystalline lattice. The existence of quark matter in the core of a neutron star may have significant consequences for its thermal evolution, which for thousands of years is facilitated primarily by neutrino emission. In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the core. To this end we calculate the equation of state using the relativistic mean-field approximation to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures (lesssim10^9 K) and quark fractions (lesssim 30% , and that contributions due to lattice vibrations are insignificant compared to static-lattice contributions.

  7. Neutrino emissivity in the quark-hadron mixed phase of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Spinella, William M. [Computational Science Research Center San Diego State University, San Diego, CA (United States); San Diego State University, Department of Physics, San Diego, CA (United States); Weber, Fridolin [San Diego State University, Department of Physics, San Diego, CA (United States); University of California San Diego, Center for Astrophysics and Space Sciences, La Jolla, CA (United States); Contrera, Gustavo A. [CONICET, Buenos Aires (Argentina); CONICET - Dept. de Fisica, UNLP, IFLP, La Plata (Argentina); Universidad Nacional de La Plata, Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, La Plata (Argentina); Orsaria, Milva G. [CONICET, Buenos Aires (Argentina); Universidad Nacional de La Plata, Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, La Plata (Argentina)

    2016-03-15

    Numerous theoretical studies using various equation of state models have shown that quark matter may exist at the extreme densities in the cores of high-mass neutron stars. It has also been shown that a phase transition from hadronic matter to quark matter would result in an extended mixed phase region that would segregate phases by net charge to minimize the total energy of the phase, leading to the formation of a crystalline lattice. The existence of quark matter in the core of a neutron star may have significant consequences for its thermal evolution, which for thousands of years is facilitated primarily by neutrino emission. In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the core. To this end we calculate the equation of state using the relativistic mean-field approximation to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures (

  8. D4 flavor symmetry for neutrino masses and mixing

    International Nuclear Information System (INIS)

    We present the D4xZ2 flavor symmetry, which is different from the previous work by Grimus and Lavoura. Our model reduces to the standard model in the low energy and there is no FCNC at the tree level. Putting the experimental data, parameters are fixed, and then the implication of our model is discussed. The condition to realize the tri-bimaximal mixing is presented. The possibility for stringy realization of our model is also discussed

  9. An A4 x Z4 model for neutrino mixing

    CERN Document Server

    BenTov, Yoni; Zee, A

    2012-01-01

    The A4 x U(1) flavor model of He, Keum, and Volkas is extended to provide a minimal modification to tribimaximal mixing that accommodates a nonzero reactor angle theta13 ~ 0.1. The sequestering problem is circumvented by forbidding superheavy scales and large coupling constants which would otherwise generate sizable RG flows. The model is compatible with (but does not require) a stable or metastable dark matter candidate in the form of a complex scalar field with unit charge under a discrete subgroup Z4 of the U(1) flavor symmetry.

  10. Revisiting Bimaximal Neutrino Mixing in a Model with S4 Discrete Symmetry

    CERN Document Server

    Altarelli, G; Merlo, L

    2009-01-01

    In view of the fact that the data on neutrino mixing are still compatible with a situation where Bimaximal mixing is valid in first approximation and it is then corrected by terms of order of the Cabibbo angle, arising from the diagonalization of the charged lepton masses, we construct a model based on the discrete group S4 where those properties are naturally realized. The model is supersymmetric in 4-dimensions and the complete flavour group is S4 x Z4 x U(1)_FN, which also allows to reproduce the hierarchy of the charged lepton spectrum. The only fine tuning needed in the model is to reproduce the small observed value of r, the ratio between the neutrino mass squared differences. Once the relevant parameters are set to accommodate r then the spectrum of light neutrinos shows a moderate normal hierarchy and is compatible, within large ambiguities, with the constraints from leptogenesis as an explanation of the baryon asymmetry in the Universe.

  11. Neutrino factories

    CERN Document Server

    Dydak, Friedrich

    2002-01-01

    The discovery of neutrino oscillations marks a major milestone in the history of neutrino physics, and opens a window to what lies beyond the Standard Model. Many current and forthcoming experiments will answer open questions; however, a major step forward, up to and possibly including CP violation in the neutrino mixing matrix, will be offered by the neutrino beams from a neutrino factory. The neutrino factory is a new concept for producing neutrino beams of unprecedented quality in terms of intensity, flavour composition, and precision of the beam parameters. These beams enable the exploration of otherwise inaccessible domains in neutrino oscillation physics by exploiting baselines of planetary dimensions. Suitable detectors pose formidable challenges but seem within reach with only moderate extrapolations from existing technologies. Although the main physics attraction of the neutrino factory is in the area of neutrino oscillations, an interesting spectrum of further opportunities ranging from high-precisi...

  12. 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.

  13. A field-theoretical approach to entanglement in neutrino mixing and oscillations

    CERN Document Server

    Blasone, M; De Siena, S; Illuminati, F

    2014-01-01

    The phenomena of particle mixing and flavor oscillations in elementary particle physics can be addressed by the point of view of quantum information theory, and described in terms of multi-mode entanglement of single-particle states. In this paper we show that such a description can be extended to the domain of quantum field theory, where we uncover a fine structure of quantum correlations associated with multi-mode, multi-particle entanglement. By means of an entanglement measure based on the linear entropies associated with all the possible bipartitions, we analyze the entanglement in the states of flavor neutrinos and anti-neutrinos. Remarkably, we show that the entanglement is connected with experimentally measurable quantities, i.e. the variances of the lepton numbers and charges.

  14. Implications of recent data on neutrino mixing and lepton flavour violating decays for the Zee model

    Science.gov (United States)

    He, Xiao-Gang; Majee, Swarup Kumar

    2012-03-01

    We study implications of recent data on neutrino mixing from T2K, MINOS, Double Chooz and μ → eγ from MEG for the Zee model. The simplest version of this model has been shown to be ruled out by experimental data some time ago. The general Zee model is still consistent with recent data. We demonstrate this with a constrained Zee model based on naturalness consideration. In this constrained model, only inverted mass hierarchy for neutrino masses is allowed, and θ 13 must be non-zero in order to have correct ratio for neutrino mass-squared differences and for mixing in solar and atmospherical neutrino oscillations. The best-fit value of our model for θ 13 is 8.91° from T2K and MINOS data, very close to the central value obtained by Double Chooz experiment. There are solutions with non-zero CP violation with the Jarlskog parameter predicted in the range ±0.039, ±0.044 and ±0.048 respectively for a 1 σ, 2 σ and 3 σ ranges of other input parameters. However, without any constraint on the θ 13-parameter above respective ranges become ±0.049, ±0.053 and ±0.056. We analyse different cases to obtain a branching ratio for μ → eγ close to the recent MEG bound. We also discuss other radiative as well as the charged trilepton flavour violating decay modes of the τ-lepton.

  15. Spontaneous breaking of flavor symmetry and naturalness of nearly degenerate neutrino masses and bi-maximal mixing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The gauge model with SO(3)F flavor symmetry and three Higgs triplets is studied. We show how the intriguing nearly degenerate neutrino mass and bi-maximal mixing scenario comes out naturally after spontaneous breaking of the symmetry. The hierarchy between the neutrino mass-squared differences, which is needed for reconciling both solar and atmospheric neutrino data, naturally results from an approximate permutation symmetry. The model can also lead to interesting phenomena on lepton-flavor violations via the SO(3)F gauge interactions.

  16. Constraints on anomalous charged current couplings, tau neutrino mass and fourth generation mixing from tau leptonic branching fractions

    International Nuclear Information System (INIS)

    We use recent experimental measurements of tau branching fractions to determine the weak charged current magnetic and electric dipole moments of the tau and the Michel parameter η with unprecedented precision. These results are then used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models. We also present new constraints on the mass of the tau neutrino and its mixing with a fourth generation neutrino

  17. Neutrino Oscillations with Three Active and Three Sterile Neutrinos

    Science.gov (United States)

    Kisslinger, Leonard S.

    2016-07-01

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

  18. Constructing the large mixing angle MNS matrix in see-saw models with right-handed neutrino dominance

    CERN Document Server

    King, S F

    2002-01-01

    Recent SNO results strongly favour the large mixing angle (LMA) MSW solar solution. We argue that there are only two technically natural low energy neutrino mass matrix structures consistent with the LMA MSW solution, corresponding to either a hierarchy or an inverted hierarchy with pseudo-Dirac neutrinos. We first present a model-independent analysis in which we diagonalise each of these two mass matrix structures to leading order in $\\theta_{13}$ and extract the neutrino masses, mixing angles and phases. In this analysis we express the MNS matrix to leading order in the small angle $\\theta_{13}$ including the neutrino {\\em and} charged lepton mixing angles and phases, the latter playing a crucial r\\^{o}le for allowing the inverted hierarchy solution to be consistent with the LMA MSW solution. We then consider the see-saw mechanism with right-handed neutrino dominance and show how the successful neutrino mass matrix structures may be constructed with no tuning and with small radiative corrections, leading to...

  19. The 2-3 symmetry: Flavour Changing $b$, $\\tau$ Decays and Neutrino Mixing

    CERN Document Server

    Datta, A; Datta, Alakabha; Donnell, Patrick J. O'

    2005-01-01

    The observed pattern of neutrino mixing may be the result of a 2-3($ \\mu- \\tau$) symmetry in the leptonic sector. We consider a two higgs doublet model with a 2-3 symmetry in the down type quark and the charged lepton sector. The breaking of the 2-3 symmetry by the strange quark mass and the muon mass leads to FCNC in the quark sector and the charged lepton sector that are suppressed by ${m_s \\over m_b}$ and ${m_{\\mu} \\over m_{\\tau}}$ in addition to the mass of the heavy higgs boson of the second higgs doublet. A higgs boson mass of $ m_H \\sim 900$ GeV can explain the deviation from standard model reported in several rare B decays. Predictions for other B decays are made and new CP phase is predicted in $B_{s}-{\\bar{B}_{s}}$ mixing. The lepton flavour violating decays $ \\tau \\to \\mu \\bar{l(q)} l(q)$ are below the experimental limits. The breaking of 2-3 symmetry in the lepton sector can lead to deviations of the atmospheric neutrino mixing angle from the maximal value by $ \\sim 2$ degrees.

  20. Measuring the Leptonic CP Phase in Neutrino Oscillations with Non-Unitary Mixing

    CERN Document Server

    Ge, Shao-Feng; Tortola, M; Valle, J W F

    2016-01-01

    Non-unitary neutrino mixing implies an extra CP violating phase that can fake the leptonic Dirac CP phase $\\delta_{CP}$ of the simplest three-neutrino mixing benchmark scheme. This would hinder the possibility of probing for CP violation in accelerator-type experiments. We take T2K and T2HK as examples to demonstrate the degeneracy between the "standard" (or "unitary") and "non-unitary" CP phases. We find, under the assumption of non-unitary mixing, that their CP sensitivities severely deteriorate. Fortunately, the TNT2K proposal of supplementing T2(H)K with a $\\mu$DAR source for better measurement of $\\delta_{CP}$ can partially break the CP degeneracy by probing both $\\cos \\delta_{CP}$ and $\\sin \\delta_{CP}$ dependences in the wide spectrum of the $\\mu$DAR flux. We also show that the further addition of a near detector to the $\\mu$DAR setup can eliminate the degeneracy completely.

  1. NuTeV anomaly, neutrino mixing, and a heavy Higgs boson

    International Nuclear Information System (INIS)

    Recent results from the NuTeV experiment at Fermilab and the deviation of the Z invisible width, measured at CERN LEP and the SLAC Linear Collider, from its standard model (SM) prediction suggest the suppression of neutrino-Z couplings. Such suppressions occur naturally in models which mix the neutrinos with heavy gauge singlet states. We postulate a universal suppression of the Zνν couplings by a factor of (1-ε) and perform a fit to the Z-pole and NuTeV observables with ε and the oblique correction parameters S and T. Compared to a fit with S and T only, the inclusion of ε leads to a dramatic improvement in the quality of the fit. The values of S and T preferred by the fit can be obtained within the SM by a simple increase in the Higgs boson mass. However, if the W mass is also included in the fit, a non-zero U parameter becomes necessary which cannot be supplied within the SM. The preferred value of ε suggests that the seesaw mechanism may not be the reason why neutrinos are so light

  2. Neutrino neutral current isoscalar excitations in 12C-isospin mixing, II

    International Nuclear Information System (INIS)

    The neutrino-neutral current isoscalar excitation of 12C( (1+; T = 0; 12.71 MeV) is investigated systematically to examine the specific roles of the various pieces of the neutral current. An effective Hamiltonian for the (isoscalar) neutrino-nucleus neutral current interaction is derived, within the context of the standard electroweak theory. The hadronic part of the neutral current interaction is found to be vectorial. Numerical results for the isoscalar total cross sections are found to satisfy the Primakoff inequality. The T = 1 admixture into the 12C( (1+; T = 0; 12.71 MeV) from the 12C( (1+; T = 1; 15.1 MeV) is taken into account. It is found that the isospin admixtures makes the total cross sections for the neutrino and antineutrino excitation of the 1+; 12.71 MeV in 12C different. The asymmetry R is thus a direct measure of T = 1 admixture. When the T-1 admixture is large (0.2), the Primakoff inequality is disturbed. Further effects of isospin mixing on the total cross sections are discussed

  3. The Sensitivity of a Lithium Experiment on Solar Neutrinos to the Mixing Angle theta_{12}

    OpenAIRE

    Kopylov, Anatoly; Petukhov, Valery

    2003-01-01

    A lithium-based radiochemical detector is aimed primarily to detect neutrinos from CNO cycle what will provide a direct proof of its existence and will be a stringent test of the theory of stellar evolution. Another task which can be solved by this experiment is to measure a mixing angle $\\theta_{12}$. The sensitivity of a lithium experiment to $\\theta_{12}$ was calculated by Monte-Carlo following the proposed original technique which can be used as a complimentary one to a chi-square techniq...

  4. Nonzero theta(13) for neutrino mixing in the context of A(4) symmetry

    CERN Document Server

    Ma, Ernest

    2011-01-01

    In the original 2004 paper which first derived tribimaximal mixing in the context of A(4), i.e. the non-Abelian finite symmetry group of the tetrahedron (Plato's fire), as its simplest application, it was also pointed out how theta(13) nonzero may be accommodated. On the strength of the new T2K result that 0.03 (0.04) < sin^2 2 theta(13) < 0.28 (0.34) for delta(CP)=0 and normal (inverted) neutrino mass hierarchy, we perform a more detailed analysis of how this original idea may be realized in the context of A(4).

  5. 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.

  6. 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.

  7. Neutrino masses and large mixings as a indirect signature of grand unified theory

    International Nuclear Information System (INIS)

    Grand unified theory (GUT) unifies not only three forces (electromagnetic force, strong force and weak force) but also quarks and leptons. As an experimental support for the unification of forces, it is well-known that three gauge couplings meet at a scale (the GUT scale). However, it is not so well-known that there is an experimental support even for the unification of matters (quarks and leptons). We explain the indirect support in this document and show that the important key is what the neutrino experiments have revealed for 20 years. Concretely, for the unification of matters in SU(5) GUT, various observed hierarchies of quark and lepton masses and mixings can be understood only from one assumption that '10 dimensional fields of SU(5) induce stronger hierarchy for the Yukawa couplings than 5-bar fields'. For this explanation, the knowledges on neutrino masses and mixings are critical. In the end, we comment E6 unification in which the above assumption in the SU(5) GUT can be induced. (author)

  8. Neutrino oscillograms of the Earth: effects of 1-2 mixing and CP-violation

    CERN Document Server

    Akhmedov, Evgeny Kh; Smirnov, Alexei Yu

    2008-01-01

    We develop a comprehensive description of three flavor neutrino oscillations inside the Earth in terms of neutrino oscillograms in the whole range of nadir angles and for energies above 0.1 GeV. The effects of the 1-2 mass splitting and mixing as well the interference of the 1-2 and 1-3 modes of oscillations are quantified. The 1-2 mass splitting and mixing lead to the appearance, apart from the resonance MSW peaks, of the parametric resonance peak for core-crossing trajectories at E_nu ~= 0.2 GeV. We show that the interference effects, in particular CP violation, have a domain structure with borders determined by the solar and atmospheric magic lines and the lines of the interference phase condition. The dependence of the oscillograms on the Dirac CP-violating phase is studied. We show that for sin^2(2 theta13) << 0.1 the strongest dependence of the oscillograms on delta is in the 1-2 and 1-3 resonance regions.

  9. Neutrino emissivity in the quark-hadron mixed phase of neutron stars

    CERN Document Server

    Spinella, William M; Contrera, Gustavo A; Orsaria, Milva G

    2015-01-01

    Numerous theoretical studies using various equation of state models have shown that quark matter may exist at the extreme densities in the cores of high-mass neutron stars. It has also been shown that a phase transition from hadronic matter to quark matter would result in an extended mixed phase region that would segregate phases by net charge to minimize the total energy of the phase, leading to the formation of a crystalline lattice. The existence of quark matter in the core of a neutron star may have significant consequences for its thermal evolution, which for thousands of years is facilitated primarily by neutrino emission. In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the core. To this end we calculate the equation of state using the relativistic mean-field approximation to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron m...

  10. Neutrinos in particle physics, astronomy, and cosmology

    CERN Document Server

    Xing, Zhi-Zhong

    2011-01-01

    ""Neutrinos in Particle Physics, Astronomy and Cosmology"" provides a comprehensive and up-to-date introduction to neutrino physics, neutrino astronomy and neutrino cosmology. The intrinsic properties and fundamental interactions of neutrinos are described, as is the phenomenology of lepton flavor mixing, seesaw mechanisms and neutrino oscillations. The cosmic neutrino background, stellar neutrinos, supernova neutrinos and ultrahigh-energy cosmic neutrinos, together with the cosmological matter-antimatter asymmetry and other roles of massive neutrinos in cosmology, are discussed in detail. Thi

  11. Are Neutrinos Democratic?

    CERN Document Server

    Karl, G

    2002-01-01

    We generalize the notion of democratic mixing matrices for neutrinos and propose a scheme in which the electron neutrino is a superposition of three different mass eigenstates with equal weights. This scheme accounts for the recent SNO results as well as atmospheric muon neutrino and electron neutrino data. The outcomes of reactor neutrino and accelerator experiments are also discussed.

  12. Predictions for the Majorana CP violation phases in the neutrino mixing matrix and neutrinoless double beta decay

    Science.gov (United States)

    Girardi, I.; Petcov, S. T.; Titov, A. V.

    2016-10-01

    We obtain predictions for the Majorana phases α21 / 2 and α31 / 2 of the 3 × 3 unitary neutrino mixing matrix U = Ue† Uν, Ue and Uν being the 3 × 3 unitary matrices resulting from the diagonalisation of the charged lepton and neutrino Majorana mass matrices, respectively. We focus on forms of Ue and Uν permitting to express α21 / 2 and α31 / 2 in terms of the Dirac phase δ and the three neutrino mixing angles of the standard parametrisation of U, and the angles and the two Majorana-like phases ξ21 / 2 and ξ31 / 2 present, in general, in Uν. The concrete forms of Uν considered are fixed by, or associated with, symmetries (tri-bimaximal, bimaximal, etc.), so that the angles in Uν are fixed. For each of these forms and forms of Ue that allow to reproduce the measured values of the three neutrino mixing angles θ12, θ23 and θ13, we derive predictions for phase differences (α21 / 2 -ξ21 / 2), (α31 / 2 -ξ31 / 2), etc., which are completely determined by the values of the mixing angles. We show that the requirement of generalised CP invariance of the neutrino Majorana mass term implies ξ21 = 0 or π and ξ31 = 0 or π. For these values of ξ21 and ξ31 and the best fit values of θ12, θ23 and θ13, we present predictions for the effective Majorana mass in neutrinoless double beta decay for both neutrino mass spectra with normal and inverted ordering.

  13. From the measurement of the θ13 mixing angle to the search for geo-neutrinos: studying νe-bare with Double Chooz and Borexino

    International Nuclear Information System (INIS)

    Double Chooz is a reactor neutrino oscillation experiment which aims at measuring the θ13 mixing angle thanks to two identical detectors located at different distances from the two reactors of the Chooz nuclear power plant, in the French Ardennes. While the near detector will start taking data in fall 2014 to normalize the flux of the neutrinos emitted by the nuclear reactors, the far detector is running since April 2011 and allows to observe the neutrinos disappearance through the neutrino oscillation phenomenon. This thesis is also dedicated to the Borexino experiment which was designed to observe solar neutrinos. Due to its low background level as well as its position in a nuclear free country, Italy, Borexino is also sensitive to geo-neutrinos. This thesis presents both the Double Chooz and Borexino experiments, from the description of the detectors to the main results, with a special attention to the background and its rejection. Studies on the neutrino directionality with these two experiments are also detailed. In the case of Double Chooz, since the neutrinos are coming from the two nuclear reactors, the precision of the analysis method can be assessed. This thesis presents also for the first time the possibility to retrieve the initial direction of the neutrinos when the neutrons created in the inverse beta decay reactions are captured on hydrogen. In the case of Borexino, neutrino directionality information could facilitate the discrimination between geo-neutrinos and neutrinos from nuclear reactors. (author)

  14. 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.

  15. The neutrino mixing matrix could (almost) be diagonal with entries {\\pm}1

    CERN Document Server

    BenTov, Yoni

    2012-01-01

    It is consistent with the measurement of \\theta_13 ~ 0.15 by Daya Bay to suppose that, in addition to being unitary, the neutrino mixing matrix is also almost hermitian, and thereby only a small perturbation from diag(+1,-1,-1) in a suitable basis. We suggest this possibility simply as an easily falsifiable ansatz that has not already been studied, as well as to offer a potentially useful means of organizing the experimental data. We explore the phenomenological implications of this ansatz and parametrize one type of deviation from the leading order relation |V_e3| \\approx |V_\\tau 1|. We also emphasize the group-invariant angle between orthogonal matrices as a means of comparing to data. The discussion is purely phenomenological, without any attempt to derive the condition V{\\dag} \\approx V from a fundamental theory.

  16. Neutrino Oscillation Probabilities in Matter with Direct and Indirect Unitarity Violation in the Lepton Mixing Matrix

    CERN Document Server

    Li, Yu-Feng

    2015-01-01

    In the presence of both direct and indirect unitarity violation in the lepton mixing matrix, we derive a complete set of series expansion formulas for neutrino oscillation probabilities in matter of constant density. Expansions in the mass hierarchy parameter $\\alpha \\equiv \\Delta m_{21}^{2} / \\Delta m_{31}^{2}$ and those unitarity violation parameters $s^{2}_{ij}$ (for i = 1, 2, 3 and j = 4, 5, 6) up to the first order are studied in this paper. We analyse the accuracy of the analytical series expansion formulas in different regions of L / E. A detailed numerical analysis is also performed, of which the different effects of the direct and the indirect unitarity violation are particularly emphasized. We also study in this paper the summed $\

  17. Experimental Neutrino Physics: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Charles E.; Maricic, Jelena

    2012-09-05

    Experimental studies of neutrino properties, with particular emphasis on neutrino oscillation, mass and mixing parameters. This research was pursued by means of underground detectors for reactor anti-neutrinos, measuring the flux and energy spectra of the neutrinos. More recent investigations have been aimed and developing detector technologies for a long-baseline neutrino experiment (LBNE) using a neutrino beam from Fermilab.

  18. A PRECISION MEASUREMENT OF THE NEUTRINO MIXING ANGLE THETA (SUB 13) USING REACTOR ANTINEUTRINOS AT DAYA BAY.

    Energy Technology Data Exchange (ETDEWEB)

    KETTELL, S.; ET AL.

    2006-10-16

    This document describes the design of the Daya Bay reactor neutrino experiment. Recent discoveries in neutrino physics have shown that the Standard Model of particle physics is incomplete. The observation of neutrino oscillations has unequivocally demonstrated that the masses of neutrinos are nonzero. The smallness of the neutrino masses (<2 eV) and the two surprisingly large mixing angles measured have thus far provided important clues and constraints to extensions of the Standard Model. The third mixing angle, {delta}{sub 13}, is small and has not yet been determined; the current experimental bound is sin{sup 2} 2{theta}{sub 13} < 0.17 at 90% confidence level (from Chooz) for {Delta}m{sub 31}{sup 2} = 2.5 x 10{sup -3} eV{sup 2}. It is important to measure this angle to provide further insight on how to extend the Standard Model. A precision measurement of sin{sup 2} 2{theta}{sub 13} using nuclear reactors has been recommended by the 2004 APS Multi-divisional Study on the Future of Neutrino Physics as well as a recent Neutrino Scientific Assessment Group (NUSAG) report. We propose to perform a precision measurement of this mixing angle by searching for the disappearance of electron antineutrinos from the nuclear reactor complex in Daya Bay, China. A reactor-based determination of sin{sup 2} 2{theta}{sub 13} will be vital in resolving the neutrino-mass hierarchy and future measurements of CP violation in the lepton sector because this technique cleanly separates {theta}{sub 13} from CP violation and effects of neutrino propagation in the earth. A reactor-based determination of sin{sup 2} 2{theta}{sub 13} will provide important, complementary information to that from long-baseline, accelerator-based experiments. The goal of the Daya Bay experiment is to reach a sensitivity of 0.01 or better in sin{sup 2} 2{theta}{sub 13} at 90% confidence level.

  19. Neutrino Lensing

    Institute of Scientific and Technical Information of China (English)

    LUO Xin-Lian

    2009-01-01

    Due to the intrinsic properties of neutrinos, the gravitational lens effect for a neutrino should be more colorful and meaningful than the normal lens effect of a photon. Other than the experiments operated at terrestrial laboratory, in principle, we can propose a completely new astrophysical method to determine not only the nature of the gravity of lens objects but also the mixing parameters of neutrinos by analyzing neutrino trajectories near the central objects.However, the angular, energy and time resolution of the neutrino telescopes are still comparatively poor, so we just concentrate on the two classical tests of general relativity, i.e.the angular deflection and the time delay of the neutrino by a lens object as a preparative work in this paper.In addition, some simple properties of neutrino lensing are investigated.

  20. Deviation from tri-bimaximal mixings through flavour twisters in inverted and normal hierarchical neutrino mass models

    Indian Academy of Sciences (India)

    N Nimai Singh; Monisa Rajkhowa; Abhijit Borah

    2007-10-01

    We explore a novel possibility for lowering the solar mixing angle (12) from tri-bimaximal mixings, without sacrificing the predictions of maximal atmospheric mixing angle (23 = 45°) and zero reactor angle (13 = 0°) in the inverted and normal hierarchical neutrino mass models having 2-3 symmetry. This can be done through the identification of a flavour twister term in the texture of neutrino mass matrix and the variation of such term leads to lowering of solar mixing angle. For the observed ranges of $ m_{21}^{2}$ and $ m_{23}^{2}$, we calculate the predictions on tan2 12 = 0.5, 0.45, 0.35 for different input values of the parameters in the neutrino mass matrix. We also observe a possible transition from inverted hierarchical model having even CP parity (Type-IHA) to inverted hierarchical model having odd CP parity (Type-IHB) in the first two mass eigenvalues, when there is a change in input values of parameters in the same mass matrix. The present work differs from the conventional approaches for the deviations from tri-bimaximal mixing, where the 2-3 symmetry is broken, leading to 23 ≠ 45° and 13 ≠ 0°.

  1. Total cross section measurement of muon neutrinos on isoscalar target. Exact determination of the electroweak mixing parameter

    International Nuclear Information System (INIS)

    The work presented in this thesis is concerned with high energy muon-neutrino nucleon interactions. The experiment was performed at CERN in 1984 using the CHARM marble target-calorimeter exposed to the 160 GeV narrow band beam. The experimental analysis is based on an event-by-event classification of neutral currents (NC) and charged currents (CC) interactions and on precise measurements of neutrinos and antineutrinos fluxes. This leads to precise measurements of CC total cross-sections of neutrinos and antineutrinos between 10 and 160 GeV and of NC to CC ratios of total cross-sections of events with hadron energy greater than 4 GeV: R neutrino and Rantineutrino. From the measurements of Rneutrino and of the ratio of CC total cross-sections of antineutrinos and neutrinos, we obtain a high precision value of the electroweak mixing angle. Comparison of this result with those obtained in proton-antiproton collisions make it possible to derive a measurement of electroweak radiative corrections and a precise determination of ρ

  2. Neutrino Mass Models

    OpenAIRE

    King, S. F.

    2003-01-01

    This is a review article about neutrino mass models, particularly see-saw models involving three active neutrinos which are capable of describing both the atmospheric neutrino oscillation data, and the large mixing angle MSW solar solution, which is now uniquely specified by recent data. We briefly review the current experimental status, show how to parametrise and construct the neutrino mixing matrix, and present the leading order neutrino Majorana mass matrices. We then introduce the see-sa...

  3. Optimizing the determination of the neutrino mixing angle θ13 from reactor data

    Science.gov (United States)

    Khan, Amir N.; McKay, Douglas W.; Ralston, John P.

    2014-07-01

    The technical breakthroughs of multiple detectors developed by Daya Bay and RENO collaborations have gotten great attention. Yet the optimal determination of neutrino mixing parameters from reactor data depends on the statistical method and demands equal attention. We find that a straightforward method using minimal parameters will generally outperform a multi-parameter method by delivering more reliable values with sharper resolution. We review standard confidence levels and statistical penalties for models using extra parameters, and apply those rules to our analysis. We find that the methods used in recent work of the Daya Bay and RENO collaborations have several undesirable properties. The existing work also uses nonstandard measures of significance which we are unable to explain. A central element of the current methods consists of variationally fitting many more parameters than data points. As a result, the experimental resolution of sin2(2θ13) is degraded. The results also become extremely sensitive to certain model parameters that can be adjusted arbitrarily. The number of parameters to include in evaluating significance is an important issue that has generally been overlooked. The measures of significance applied previously would be consistent if and only if all parameters but one were considered to have no physical relevance for the experiment's hypothesis test. Simpler, more transparent methods can improve the determination of the mixing angle θ13 from reactor data, and exploit the advantages from superb hardware technique of the experiments. We anticipate that future experimental analysis will fully exploit those advantages.

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

    OpenAIRE

    Adamson, P.; Andreopoulos, C.; Armstrong, R.; Auty, D. J.; Ayres, D. S.; Backhouse, C.; Barr, G.; Bishai, M.; Blake, A.; Bock, G. J.; Devenish, N. E.; Falk, E.; Hartnell, J.; Lefeuvre, G.; et al, ...

    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 m...

  5. Neutrino masses and tribimaximal mixing in Minimal renormalizable SUSY SU(5) Grand Unified Model with A4 Flavor symmetry

    CERN Document Server

    Ciafaloni, Paolo; Torrente-Lujan, Emilio; Urbano, Alfredo

    2009-01-01

    We analyze all possible extensions of the recently proposed minimal renormalizable SUSY SU(5) grand unified model with the inclusion of an additional A4 flavor symmetry. We find that there are 5 possible Cases but only one of them is phenomenologically interesting. We develop in detail such Case and we show how the fermion masses and mixing angles come out. As prediction we obtain the neutrino masses of order of 0.1 eV with an inverted hierarchy.

  6. Effect of cross-section models on the validity of sterile neutrino mixing limits

    CERN Document Server

    Stowell, Patrick; Cartwright, Susan

    2015-01-01

    Charged-Current Quasi-Elastic (CCQE) neutrino scattering is the signal channel for sterile neutrino oscillation experiments. Recent cross-section measurements have made it clear that the current understanding of this channel in the few-GeV region is incomplete, and several sophisticated theoretical models have been proposed to tackle this issue, although it is not clear which model best describes the global dataset. In this paper we argue that the current uncertainty surrounding CCQE cross-sections is a serious problem for experiments seeking to produce sterile neutrino limits. We perform a sterile neutrino analysis with published MINERvA data as an illustrative example. We highlight the need for caution in interpreting sterile neutrino limits given the context of incomplete cross-section model information.

  7. The Intermediate Neutrino Program

    CERN Document Server

    Adams, C; Ankowski, A M; Asaadi, J A; Ashenfelter, J; Axani, S N; Babu, K; Backhouse, C; Band, H R; Barbeau, P S; Barros, N; Bernstein, A; Betancourt, M; Bishai, M; Blucher, E; Bouffard, J; Bowden, N; Brice, S; Bryan, C; Camilleri, L; Cao, J; Carlson, J; Carr, R E; Chatterjee, A; Chen, M; Chen, S; Chiu, M; Church, E D; Collar, J I; Collin, G; Conrad, J M; Convery, M R; Cooper, R L; Cowen, D; Davoudiasl, H; De Gouvea, A; Dean, D J; Deichert, G; Descamps, F; DeYoung, T; Diwan, M V; Djurcic, Z; Dolinski, M J; Dolph, J; Donnelly, B; Dwyer, D A; Dytman, S; Efremenko, Y; Everett, L L; Fava, A; Figueroa-Feliciano, E; Fleming, B; Friedland, A; Fujikawa, B K; Gaisser, T K; Galeazzi, M; Galehouse, D C; Galindo-Uribarri, A; Garvey, G T; Gautam, S; Gilje, K E; Gonzalez-Garcia, M; Goodman, M C; Gordon, H; Gramellini, E; Green, M P; Guglielmi, A; Hackenburg, R W; Hackenburg, A; Halzen, F; Han, K; Hans, S; Harris, D; Heeger, K M; Herman, M; Hill, R; Holin, A; Huber, P; Jaffe, D E; Johnson, R A; Joshi, J; Karagiorgi, G; Kaufman, L J; Kayser, B; Kettell, S H; Kirby, B J; Klein, J R; Kolomensky, Yu G; Kriske, R M; Lane, C E; Langford, T J; Lankford, A; Lau, K; Learned, J G; Ling, J; Link, J M; Lissauer, D; Littenberg, L; Littlejohn, B R; Lockwitz, S; Lokajicek, M; Louis, W C; Luk, K; Lykken, J; Marciano, W J; Maricic, J; Markoff, D M; Caicedo, D A Martinez; Mauger, C; Mavrokoridis, K; McCluskey, E; McKeen, D; McKeown, R; Mills, G; Mocioiu, I; Monreal, B; Mooney, M R; Morfin, J G; Mumm, P; Napolitano, J; Neilson, R; Nelson, J K; Nessi, M; Norcini, D; Nova, F; Nygren, D R; Gann, G D Orebi; Palamara, O; Parsa, Z; Patterson, R; Paul, P; Pocar, A; Qian, X; Raaf, J L; Rameika, R; Ranucci, G; Ray, H; Reyna, D; Rich, G C; Rodrigues, P; Romero, E Romero; Rosero, R; Rountree, S D; Rybolt, B; Sanchez, M C; Santucci, G; Schmitz, D; Scholberg, K; Seckel, D; Shaevitz, M; Shrock, R; Smy, M B; Soderberg, M; Sonzogni, A; Sousa, A B; Spitz, J; John, J M St; Stewart, J; Strait, J B; Sullivan, G; Svoboda, R; Szelc, A M; Tayloe, R; Thomson, M A; Toups, M; Vacheret, A; Vagins, M; Van de Water, R G; Vogelaar, R B; Weber, M; Weng, W; Wetstein, M; White, C; White, B R; Whitehead, L; Whittington, D W; Wilking, M J; Wilson, R J; Wilson, P; Winklehner, D; Winn, D R; Worcester, E; Yang, L; Yeh, M; Yokley, Z W; Yoo, J; Yu, B; Yu, J; Zhang, C

    2015-01-01

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summ...

  8. The Intermediate Neutrino Program

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C.; et al.

    2015-03-23

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

  9. A neutrino mixing model based on an $A_4\\times Z_3\\times Z_4$ flavour symmetry

    CERN Document Server

    Ky, Nguyen Anh; Van, Nguyen Thi Hong

    2016-01-01

    A model of a neutrino mixing with an $A_4\\times Z_3\\times Z_4$ flavour symmetry is suggested. In addition to the standard model fields, the present model contains six new fields which transform under different representations of $A_4\\times Z_3\\times Z_4$. The model is constructed to slightly deviate from a tri-bi-maximal model in agreement with the current experimental data, thus, all analysis can be done in the base of the perturbation method. Within this model, as an application, a relation between the mixing angles ($\\theta_{12}, \\theta_{23}, \\theta_{13}$) and the Dirac CP-violation phase ($\\delta_{CP}$) is established. This relation allows a prediction of $\\delta_{CP}$ and the Jarlskog parameter ($J_{CP}$). The predicted value $\\delta_{CP}$ is in the 1$\\sigma$ region of the global fit for both the normal- and inverse neutrino mass ordering and gives $J_{CP}$ to be within the bound $|J_{CP}|\\leq 0.04$. For an illustration, the model is checked numerically and gives values of the neutrino masses (of the ord...

  10. CP Phases of Neutrino Mixing in a Supersymmetric B-L Gauge Model with T_7 Lepton Flavor Symmetry

    CERN Document Server

    Ishimori, Hajime; Ma, Ernest

    2012-01-01

    In a recently proposed renormalizable model of neutrino mixing using the non-Abelian discrete symmetry T_7 in the context of a supersymmetric extension of the Standard Model with gauged U(1)_{B-L}, a correlation was obtained between \\theta_{13} and \\theta_{23} in the case where all parameters are real. Here we consider all parameters to be complex, thus allowing for one Dirac CP phase \\delta_{CP} and two Majorana CP phases \\alpha_{1,2}. We find a slight modification to this correlation as a function of \\delta_{CP}. For a given set of input values of \\Delta m^2_{21}, \\Delta m^2_{32}, \\theta_{12}, and \\theta_{13}, we obtain \\sin^2 2 \\theta_{23} and m_{ee} (the effective Majorana neutrino mass in neutrinoless double beta decay) as functions of \\tan \\delta_{CP}. We find that the structure of this model always yields small |\\tan \\delta_{CP}|.

  11. Neutrino refraction by the cosmic neutrino background

    CERN Document Server

    Diaz, J S

    2015-01-01

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

  12. Neutrino refraction by the cosmic neutrino background

    Science.gov (United States)

    Díaz, J. S.; Klinkhamer, F. R.

    2016-03-01

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

  13. Neutrino electromagnetic properties

    CERN Document Server

    Giunti, Carlo

    2008-01-01

    The main goal of the paper is to give a short review on a neutrino electromagnetic properties. In the introductory part of the paper a summary on what we really know about neutrinos is given: we discuss the basics of neutrino mass and mixing as well as the phenomenology of neutrino oscillations. This is important for the further discussion on a neutrino electromagnetic properties that starts with derivation of the neutrino electromagnetic vertex function in the most general form, that follows from the requirement of Lorentz invariance, for both the Dirac and Majorana cases. Then the problem of a neutrino form factors definition and calculation within gauge models is considered. In particular, we discuss a neutrino electric charge form factor and charge radius, dipole magnetic and electric and anapole form factors. Available experimental constraints on a neutrino electromagnetic properties are also reviewed, and the most important experiments on obtaining limits on a neutrino magnetic moment are discussed. A s...

  14. Global analyses of neutrino oscillation experiments

    Science.gov (United States)

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

    2016-07-01

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

  15. Global Analyses of Neutrino Oscillation Experiments

    CERN Document Server

    Gonzalez-Garcia, M C; Schwetz, Thomas

    2015-01-01

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

  16. Acquire information about neutrino parameters by detecting supernova neutrinos

    OpenAIRE

    Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

    2010-01-01

    We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein (MSW) effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle $\\theta_{13}$, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about $\\theta_{13}$ and neutrino masses ...

  17. Neutrinos in particle physics, astronomy and cosmology

    International Nuclear Information System (INIS)

    ''Neutrinos in Particle Physics, Astronomy and Cosmology'' provides a comprehensive and up-to-date introduction to neutrino physics, neutrino astronomy and neutrino cosmology. The intrinsic properties and fundamental interactions of neutrinos are described, as is the phenomenology of lepton flavor mixing, seesaw mechanisms and neutrino oscillations. The cosmic neutrino background, stellar neutrinos, supernova neutrinos and ultrahigh-energy cosmic neutrinos, together with the cosmological matter-antimatter asymmetry and other roles of massive neutrinos in cosmology, are discussed in detail. This book is intended for researchers and graduate students in the fields of particle physics, particle astrophysics and cosmology. (orig.)

  18. Ambiguity in source flux of high-energy cosmic\\/astrophysical neutrinos Effects of bi-maximal mixing and quantum-gravity induced decoherence

    CERN Document Server

    Ahluwalia, D V

    2001-01-01

    For high energy cosmic neutrinos Athar, Jezabek, and Yasuda (AJY) have recently shown that the existing data on neutrino oscillations suggests that cosmic neutrino flux at the AGN/GRB source, F(nu_e):F(nu_mu):F(nu_tau) approx 1:2:0, oscillates to F(nu_e):F(nu_mu):F(nu_tau) approx 1:1:1. These results can be confirmed at AMANDA, Baikal, ANTARES and NESTOR, and other neutrino detectors with a good flavor resolution. Here, we re-derive the AJY result from quasi bi-maximal mixing, and show that observation of F(nu_e):F(nu_mu):F(nu_tau) approx 1:1:1 does not necessarily establish cosmic neutrino flux at the AGN/GRB source to be F(nu_e):F(nu_mu):F(nu_tau) approx 1:2:0. We also note that if the length scale for the quantum-gravity induced de-coherence for astrophysical neutrinos is of the order of a Mpc, then independent of the MNS matrix, the Liu-Hu-Ge (LHG) mechanism would lead to flux equalization for the cosmic/astrophysical neutrinos.

  19. Neutrino Mixing with Non-Zero $\\theta_{13}$ and CP Violation in the 3-3-1 Model Based on $S_4$ Flavor Symmetry

    CERN Document Server

    Van Vien, Vo; Khoi, Dinh Phan

    2015-01-01

    The 3-3-1 model proposed in 2011 based on discrete symmetry $S_4$ responsible for the neutrino and quark masses is updated, in which the non-zero $\\theta_{13}$ is focused. Neutrino masses and mixings are consistent with the most recent data on neutrino oscillations without perturbation. The new feature is adding a new $SU(3)_L$ anti-sextet lying in doublet under $S_4$ which can result the non-zero $\\theta_{13}$ without perturbation, and consequently, the number of Higgs multiplets required is less than those of other models based on non-Abelian discrete symmetries and the 3-3-1 models. The exact tribimaximal form obtained with the breaking $S_4 \\rightarrow Z_3$ in charged lepton sector and $S_4 \\rightarrow \\mathcal{K}$ in neutrino sector. If both breakings $S_4\\rightarrow \\mathcal{K}$ and $\\mathcal{K} \\rightarrow Z_2$ are taken place in neutrino sector, the realistic neutrino spectrum is obtained without perturbation. The upper bound on neutrino mass and the effective mass governing neutrinoless double beta d...

  20. Neutrino mixing with nonzero θ13 and CP violation in the 3-3-1 model based on S4 flavor symmetry

    Science.gov (United States)

    Vien, Vo Van; Long, Hoang Ngoc; Khoi, Dinh Phan

    2015-06-01

    The 3-3-1 model proposed in 2011 based on discrete symmetry S4 responsible for the neutrino and quark masses is updated, in which the nonzero θ13 is focused. Neutrino masses and mixings are consistent with the most recent data on neutrino oscillations without perturbation. The new feature is adding a new SU(3)L anti-sextet lying in doublet under S4 which can result the nonzero θ13 without perturbation, and consequently, the number of Higgs multiplets required is less than those of other models based on non-Abelian discrete symmetries and the 3-3-1 models. The exact tribimaximal form obtained with the breaking S4 → Z3 in charged lepton sector and S4 →𝒦 in neutrino sector. If both breakings S4 →𝒦 and 𝒦→ Z2 are taken place in neutrino sector, the realistic neutrino spectrum is obtained without perturbation. The upper bound on neutrino mass and the effective mass governing neutrinoless double beta decay at the tree level are presented. The model predicts the Dirac CP violation phase δ = 292.45° in the normal spectrum (with θ23≠π 4) and δ = 303.14° in the inverted spectrum.

  1. $T_7$ flavor symmetry scheme for understanding neutrino mass and mixing in 3-3-1 model with neutral leptons

    CERN Document Server

    Vien, V V

    2015-01-01

    We construct a new version for the 3-3-1 model based on $T_7$ flavor symmetry where the left-handed leptons under $T_7$ differ from those of our previous work while the $\\mathrm{SU}(3)_C \\otimes \\mathrm{SU}(3)_L \\otimes \\mathrm{U}(1)_X$ gauge symmetry is retain. The flavor mixing patterns and mass splitting are obtained without perturbation. The realistic lepton mixing can be obtained if both the direction of breakings $T_7 \\rightarrow Z_3$ and $Z_3 \\rightarrow \\{\\mathrm{Identity}\\}$ are taken place in neutrino sector. Maximal CP violation is predicted and CKM matrix is the identity matrix at the tree-level.

  2. Solar neutrino oscillations

    International Nuclear Information System (INIS)

    The special properties of solar neutrinos that render this flux so uniquely important in searches for neutrino masses and flavor mixing are reviewed. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained through analogies with more familiar atomic physics phenomena

  3. Physics of heavy neutrinos

    CERN Document Server

    Gluza, J

    1996-01-01

    Theoretical and experimental situation in physics of heavy neutrinos (M_N>M_Z) is briefly presented. Various experimental bounds on heavy neutrino masses and mixings are shortly reviewed. Special attention is paid to possibility of detecting heavy neutrinos in future lepton linear colliders.

  4. Neutrino Sources and Properties

    CERN Document Server

    Vissani, Francesco

    2014-01-01

    In this lecture, prepared for PhD students, basic considerations on neutrino interactions, properties and sites of production are overviewed. The detailed content is as follows: Sect. 1, Weak interactions and neutrinos: Fermi coupling; definition of neutrinos; global numbers. Sect. 2, A list of neutrino sources: Explanatory note and examples (solar pp- and supernova-neutrinos). Sect. 3, Neutrinos oscillations: Basic formalism (Pontecorvo); matter effect (Mikheev, Smirnov, Wolfenstein); status of neutrino masses and mixings. Sect. 4, Modifying the standard model to include neutrinos masses: The fermions of the standard model; one additional operator in the standard model (Weinberg); implications. One summary table and several exercises offer the students occasions to check, consolidate and extend their understanding; the brief reference list includes historical and review papers and some entry points to active research in neutrino physics.

  5. Neutrino masses and mixings in the baryon triality constrained minimal supersymmetric standard model

    OpenAIRE

    Dreiner, Herbi K.; Hanussek, Marja; Kim, Jong-Soo; Kom, C. H.

    2011-01-01

    We discuss how the experimental neutrino oscillation data can be realized in the framework of the baryon triality ($B_3$) constrained supersymmetric Standard Model (cSSM). We show how to obtain phenomenologically viable solutions, which are compatible with the recent WMAP observations. We present results for the hierarchical, inverted and degenerate cases which illustrate the possible size and structure of the lepton number violating couplings. We work with a new, as yet unpublished version o...

  6. Four-Neutrino Oscillations at SNO

    CERN Document Server

    González-Garciá, M Concepción

    2001-01-01

    We discuss the potential of the Sudbury Neutrino Observatory (SNO) to constraint the four-neutrino mixing schemes favoured by the results of all neutrino oscillations experiments. These schemes allow simultaneous transitions of solar $\

  7. Workshop on low energy neutrino physics

    International Nuclear Information System (INIS)

    The main topics of the workshop are: the determination of the neutrino mixing angle theta-13, the experiments concerning the monitoring of reactors based on the measurement of neutrino spectra, solar neutrinos, supernovae neutrinos, geo-neutrinos, neutrino properties, neutrinoless double beta decay and future low energy neutrino detectors. This document gathers together the program of the workshop, the slides of the presentations, some abstracts and some posters

  8. Measurement of neutrino mixing angle θ13 and mass difference Δ mee2 from reactor antineutrino disappearance in the RENO experiment

    Science.gov (United States)

    Kim, Soo-Bong

    2016-07-01

    RENO (Reactor Experiment for Neutrino Oscillation) made a definitive measurement of the smallest neutrino mixing angle θ13 in 2012, based on the disappearance of reactor electron antineutrinos. The experiment has obtained a more precise value of the mixing angle and the first result on neutrino mass difference Δ mee2 from an energy and baseline dependent reactor neutrino disappearance using ∼500 days of data. Based on the ratio of inverse-beta-decay (IBD) prompt spectra measured in two identical far and near detectors, we obtain sin2 ⁡ (2θ13) = 0.082 ± 0.009 (stat .) ± 0.006 (syst .) and | Δ mee2 | = [2.62-0.23+0.21 (stat .)-0.13+0.12 (syst .) ] ×10-3 eV2. An excess of reactor antineutrinos near 5 MeV is observed in the measured prompt spectrum with respect to the most commonly used models. The excess is found to be consistent with coming from reactors. A successful measurement of θ13 is also made in an IBD event sample with a delayed signal of neutron capture on hydrogen. A precise value of θ13 would provide important information on determination of the leptonic CP phase if combined with a result of an accelerator neutrino beam experiment.

  9. A unified analysis of the reactor neutrino program towards the measurement of the {theta}{sub 13} mixing angle

    Energy Technology Data Exchange (ETDEWEB)

    Mention, G.; Motta, D. [DAPNIA/SPP, CEA Saclay, 91191 Gif sur Yvette (France); Lasserre, Th. [DAPNIA/SPP, CEA Saclay, 91191 Gif sur Yvette (France); Laboratoire Astroparticule et Cosmologie (APC), Paris (France)

    2007-04-15

    We present in this article a detailed quantitative discussion of the measurement of the leptonic mixing angle {theta}{sub 13} through currently scheduled reactor neutrino oscillation experiments. We thus focus on Double Chooz (Phase I and II), Daya Bay (Phase I and II) and RENO experiments. We perform a unified analysis, including systematics, backgrounds and accurate experimental setup in each case. Each identified systematic error and background impact has been assessed on experimental setups following published data when available and extrapolating from Double Chooz acquired knowledge otherwise. After reviewing the experiments, we present a new analysis of their sensitivities to sin{sup 2}(2{theta}{sub 13}) and study the impact of the different systematics based on the pulls approach. Through this generic statistical analysis we discuss the advantages and drawbacks of each experimental setup. (authors)

  10. A Measurement of the Weak Mixing Angle in Neutrino-Nucleon Scattering at NuTeV

    CERN Document Server

    Zeller, G P; Alton, A; Avvakumov, S; Bernstein, R H; Bodek, Arie; Bolton, T; Brau, J E; Buchholz, D A; Budd, H S; Bugel, L; Conrad, J; Drucker, R B; Formaggio, J A; Frey, R; Goldman, J; Goncharov, M; Harris, D A; Johnson, R A; Koutsoliotas, S; Kim, J H; Lamm, M J; Marsh, W; Mason, D; McNulty, C; McFarland, K S; Naples, D; Nienaber, P; Romosan, A; Sakumoto, W K; Schellman, H; Shaevitz, M H; Spentzouris, P; Stern, E G; Tamminga, B; Vakili, M; Vaitaitis, A G; Yang, U K

    1999-01-01

    The NuTeV experiment at Fermilab presents a determination of the electroweak mixing angle. High purity, large statistics samples of muon-neutrino and muon-antineutrino events allow the use of the Paschos-Wolfenstein relation. This considerably reduces systematic errors associated with charm production and other sources. With Standard Model assumptions, this measurement of sin2thw indirectly determines the W boson mass to a precision comparable to direct measurements from high energy e+e- and p-pbar colliders. NuTeV measures sin^2theta_W (on-shell) = 0.2253 +/- 0.0019(stat) +/- 0.0010(syst) which implies M_W = 80.26 +/- 0.11 GeV.

  11. Neutrinos from a core collapse supernova

    OpenAIRE

    Dighe, Amol

    2007-01-01

    The neutrino burst from a galactic supernova can help determine the neutrino mass hierarchy and $\\theta_{13}$, and provide crucial information about supernova astrophysics. Here we review our current understanding of the neutrino burst, flavor conversions of these neutrinos, and model independent signatures of various neutrino mixing scenarios.

  12. 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.

  13. Neutrino Physics (theory)

    OpenAIRE

    Langacker, Paul

    2004-01-01

    Nonzero neutrino masses are the first definitive need to extend the standard model. After reviewing the basic framework, I describe the status of some of the major issues, including tests of the basic framework of neutrino masses and mixings; the question of Majorana vs. Dirac; the spectrum, mixings, and number of neutrinos; models, with special emphasis on constraints from typical superstring constructions (which are not consistent with popular bottom-up assumptions); and other implications.

  14. Introduction to sterile neutrinos

    CERN Document Server

    Volkas, R R

    2002-01-01

    Model-building issues raised by the prospect of light sterile neutrinos are discussed in a pedagogical way. I first review the na\\"{\\i}ve proposal that sterile neutrinos be identified with ``right handed neutrinos''. A critical discussion of the simple expedient of adding three gauge singlet fermions to the usual minimal standard model matter content is followed by an examination of right handed neutrinos in extended theories. I introduce the terminology of ``fully sterile'' and ``weakly sterile'' to classify varieties usually conflated under the sterile neutrino banner. After introducing the concepts of ``technical naturalness'' and plain ``naturalness'', the unbearable lightness of being a sterile neutrino is confronted. This problem is used to motivate mirror neutrinos, whose connection with pairwise maximal mixing is emphasised. Some brief remarks about phenomenology are made throughout. The impossibility of identifying the sole sterile neutrino of the currently favoured $2 + 2$ and $3 + 1$ phenomenologic...

  15. 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...

  16. Naturally light sterile neutrinos

    CERN Document Server

    Sarkar, U

    1999-01-01

    A simple model to accomodate light sterile neutrinos naturally with large mixing with the usual neutrinos has been proposed. The standard model gauge group is extended to include an $SU(2)_S$ gauge symmetry. Heavy triplet higgs scalars give small masses to the left-handed neutrinos, while a heavy doublet higgs scalar give mixing with the sterile neutrinos of the same order of magnitude. The neutrino mass matrix thus obtained can explain the solar neutrino deficit, the atmospheric neutrino deficit, the LSND data and hot dark matter. Lepton number is violated here through decays of the heavy triplet higgs, which generates the lepton asymmetry of the universe, which in turn generates a baryon asymmetry of the universe.

  17. Dirac neutrinos from flavor symmetry

    CERN Document Server

    Aranda, Alfredo; Morisi, S; Peinado, E; Valle, J W F

    2013-01-01

    We present a model where Majorana neutrino mass terms are forbidden by the flavor symmetry group Delta(27). Neutrinos are Dirac fermions and their masses arise in the same way as that of the charged fermions, due to very small Yukawa couplings. The model fits current neutrino oscillation data and correlates the octant of the atmospheric angle with the magnitude of the lightest neutrino mass, with maximal mixing excluded for any neutrino mass

  18. Supernova neutrinos and their oscillations

    International Nuclear Information System (INIS)

    The recent observations of neutrinos from a supernova have many implications for astrophysics and particle physics. Besides containing information on the supernova, the signal depends on the properties of neutrinos. In order to interpret the recent observations, the uncertainties in supernova dynamics must be disentangled from the effects of neutrino propagation. The authors concentrate on the mixing of neutrino fluxes from neutrino oscillations, both in vacuum and in matter

  19. Effects of sudden mixing in the solar core on solar neutrinos and ice ages.

    Science.gov (United States)

    Ezer, D.; Cameron, A. G. W.

    1972-01-01

    Some numerical experiments with a solar model have been conducted in connection with the hypothesis regarding the effects of mixing in the solar core. Questions concerning a plausible mechanism by which such a mixing could be produced are explored. The variation of solar luminosity throughout the numerical experiments is shown. In connection with a great change in luminosity after a second mixing, it is suggested that the earth is presently undergoing an ice age.

  20. Long-Baseline Neutrino Experiments

    CERN Document Server

    Diwan, M V; Qian, X; Rubbia, A

    2016-01-01

    We review long-baseline neutrino experiments in which neutrinos are detected after traversing macroscopic distances. Over such distances neutrinos have been found to oscillate among flavor states. Experiments with solar, atmospheric, reactor, and accelerator neutrinos have resulted in a coherent picture of neutrino masses and mixing of the three known flavor states. We will summarize the current best knowledge of neutrino parameters and phenomenology with our focus on the evolution of the experimental technique. We proceed from the first evidence produced by astrophysical neutrino sources to the current open questions and the goals of future research.

  1. Neutrino Astrophysics

    CERN Document Server

    Volpe, Cristina

    2016-01-01

    We summarize the progress in neutrino astrophysics and emphasize open issues in our understanding of neutrino flavor conversion in media. We discuss solar neutrinos, core-collapse supernova neutrinos and conclude with ultra-high energy neutrinos.

  2. Cosmic Neutrino Flavor Democracy and Unitarity Violation at Neutrino Telescopes

    CERN Document Server

    Xing, Zhi-zhong

    2008-01-01

    Provided ultrahigh-energy cosmic neutrinos are produced from the decays of charged pions arising from proton-proton and (or) proton-gamma collisions, their flavor ratios at a neutrino telescope will be \\phi^T_e : \\phi^T_\\mu : \\phi^T_\\tau \\approx 1 : 1 : 1. We show that the exact flavor democracy can occur if the unitary neutrino mixing matrix satisfies either \\theta_13 = 0 and \\theta_{23} = \\pi/4 (CP invariance) or \\delta= \\pm \\pi/2 and \\theta_{23} = \\pi/4 (CP violation) in the standard parametrization. Allowing for slight deviations from either condition, we calculate the corresponding neutrino flavor distribution at neutrino telescopes. If the neutrino mixing matrix is non-unitary, as expected in a class of seesaw models with TeV-scale Majorana neutrinos, we demonstrate that the effect of unitarity violation on the flavor democracy of cosmic neutrinos at neutrino telescopes can be as large as several percent.

  3. KamLAND potentiality on the determination of Neutrino mixing parameters in the post SNO-NC era

    CERN Document Server

    Aliani, P; Picariello, M; Torrente-Lujan, E

    2003-01-01

    We study in detail the power of the reactor experiment kamLAND for discriminating existing solutions to the SNP and giving accurate information on neutrino masses and mixing angles. Assuming the expected signal corresponding to various ``benchmark'' points in the 2 dimensional $(\\Delta m^2,\\tan^2 \\theta)$ mixing plane, we develop a full-fledged $\\chi^2$ analysis which includes KamLAND spectrum and all the existing solar evidence. A complete modelling of statistical and known systematics errors for 1 and 3 years of data taking is also included, exclusion plots are presented. We find a much higher sensitivity especially for values of $\\Delta m^2$ lying in the central part of the LMA region. The situation would be more complicate for values closer to the border of the LMA region (the so called HLMA region, i.e. $\\Delta m^2 \\leq 2 \\times 10^{5}$ and $\\Delta m^2 \\geq 8-9 \\times 10^{-5}$ or $tan^2 \\theta$ far from $\\tan^2 \\theta = 0.5$). In this case kamLAND, with or without solar evidence, will be able only to sel...

  4. Real Invariant Matrices and Flavour-Symmetric Mixing Variables with Emphasis on Neutrino Oscillations

    OpenAIRE

    Harrison, P F.; Scott, W. G.(Particle Physics Department, Rutherford Appleton Laboratory, Didcot, UK); Weiler, T. J.

    2006-01-01

    In fermion mixing phenomenology, the matrix of moduli squared, P=(|U|^2), is well-known to carry essentially the same information as the complex mixing matrix U itself, but with the advantage of being phase-convention independent. The matrix K (analogous to the Jarlskog CP-invariant J) formed from the real parts of the mixing matrix "plaquette" products is similarly invariant. In this paper, the P and K matrices are shown to be entirely equivalent, both being directly related (in the leptonic...

  5. Sterile neutrinos at LBNE

    CERN Document Server

    Hollander, David

    2014-01-01

    In this paper we examine the sensitivity of the Long Baseline Neutrino Oscillation Experiment to the inclusion of two new sterile neutrino flavors with masses in the eV range. We implement a modified Casas-Ibarra parametrization which can accommodate medium scale mass eigenstates and introduces a new complex mixing angle. We explore the new mixing angle parameter space and demonstrate how LBNE can be used to either provide evidence for or rule out a particular model of sterile neutrinos. Certain three-flavor CP-violation scenarios cannot be distinguished from the sterile neutrinos. Constraints from the Daya Bay reactor experiment are used to help lift this degeneracy.

  6. 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.

  7. 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.

  8. 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.

  9. Minimalistic Neutrino Mass Model

    CERN Document Server

    De Gouvêa, A; Gouvea, Andre de

    2001-01-01

    We consider the simplest model which solves the solar and atmospheric neutrino puzzles, in the sense that it contains the smallest amount of beyond the Standard Model ingredients. The solar neutrino data is accounted for by Planck-mass effects while the atmospheric neutrino anomaly is due to the existence of a single right-handed neutrino at an intermediate mass scale between 10^9 GeV and 10^14 GeV. Even though the neutrino mixing angles are not exactly predicted, they can be naturally large, which agrees well with the current experimental situation. Furthermore, the amount of lepton asymmetry produced in the early universe by the decay of the right-handed neutrino is very predictive and may be enough to explain the current baryon-to-photon ratio if the right-handed neutrinos are produced out of thermal equilibrium. One definitive test for the model is the search for anomalous seasonal effects at Borexino.

  10. Progress in neutrino oscillation searches and their implications

    Indian Academy of Sciences (India)

    Srubabati Goswami

    2003-02-01

    Neutrino oscillation, in which a given flavor of neutrino transforms into another is a powerful tool for probing small neutrino masses. The intrinsic neutrino properties involved are neutrino mass squared difference 2 and the mixing angle in vacuum . In this paper I will summarize the progress that we have achieved in our search for neutrino oscillation with special emphasis on the recent results from the Sudbury Neutrino Observatory (SNO) on the measurement of solar neutrino fluxes. I will outline the current bounds on the neutrino masses and mixing parameters and discuss the major physics goals of future neutrino experiments in the context of the present picture.

  11. Uncertainties in the Solar Neutrino Flux

    CERN Document Server

    Haxton, W C

    1999-01-01

    I discuss three issues relevant to solar neutrino flux measurements: cross section uncertainties in pp chain reactions, uncertainties in the GALLEX/SAGE response to 7Be and 51Cr neutrinos, and the implications of helioseismology for nonstandard suns with mixed cores. A few comments are also offered on electron neutrino to tauon neutrino oscillations, cosmologically interesting neutrino masses, and recent proposals for supernova neutrino observatories.

  12. Yang-Mills duality as origin of generations, quark mixing and neutrino oscillations

    CERN Document Server

    Tsou, S T

    2000-01-01

    The origin of fermion generations is one of the great mysteries in particle physics. We consider here a possible solution within the Standard Model framework based on a nonabelian generalization of electric-magnetic duality. First, nonabelian duality says that dual to the colour (electric) symmetry SU(3), there is a ``colour magnetic symmetry'' $\\widetilde{SU}(3)$, which by a result of 't~Hooft is spontaneously broken and can thus play the role of the "horizontal symmetry" of generations. Second, nonabelian duality suggests the manner this symmetry is broken with frame vectors in internal symmetry space acting as Higgs fields. As a result, mass matrices factorize leading to fermion mass hierarchy. A calculation to first order gives mixing (CKM and MNS) matrices in general agreement with experiment. In particular, quark mixing is seen naturally to be weak compared with leptons, while within the lepton sector, $\\mu-\\tau$ mixing turns out near maximal but $e-\\tau$ mixing small, just as seen in recent $\

  13. On the role of the rotations and Bogoliubov transformations in neutrino mixing

    CERN Document Server

    Blasone, Massimo; Vitiello, Giuseppe

    2016-01-01

    We show that mixing transformations for Dirac fields arise as a consequence of the non-trivial interplay between rotations and Bogoliubov transformations at level of ladder operators. Indeed the non-commutativity between the algebraic generators of such transformations turns out to be responsible of the unitary inequivalence of the flavor and mass representations and of the associated vacuum structure. A possible thermodynamic interpretation is also investigated.

  14. On the rôle of rotations and Bogoliubov transformations in neutrino mixing

    Science.gov (United States)

    Blasone, M.; Gargiulo, M. V.; Vitiello, G.

    2016-10-01

    We show that mixing transformations for Dirac fields arise as a consequence of the non-trivial interplay between rotations and Bogoliubov transformations at level of ladder operators. Indeed the non-commutativity between the algebraic generators of such transformations turns out to be responsible of the unitary inequivalence of the flavor and mass representations and of the associated vacuum structure. A possible thermodynamic interpretation is also investigated.

  15. Neutrino Mass Models

    CERN Document Server

    King, S F

    2004-01-01

    This is a review article about neutrino mass models, particularly see-saw models involving three active neutrinos which are capable of describing both the atmospheric neutrino oscillation data, and the large mixing angle MSW solar solution, which is now uniquely specified by recent data. We briefly review the current experimental status, show how to parametrise and construct the neutrino mixing matrix, and present the leading order neutrino Majorana mass matrices. We then introduce the see-saw mechanism, and discuss a natural application of it to current data using the sequential dominance mechanism, which we compare to an early proposal for obtaining large mixing angles. We show how both the Standard Model and the Minimal Supersymmetric Standard Model may be extended to incorporate the see-saw mechanism, and show how the latter case leads to the expectation of lepton flavour violation. The see-saw mechanism motivates models with additional symmetries such as unification and family symmetry models, and we tab...

  16. Low-energy neutrino physics and neutrino mass

    OpenAIRE

    Boehm, F.; Vogel, P.

    1984-01-01

    Among the principal concerns in neutrino physics today are the questions of whether neutrinos are massive and, if so, whether the neutrinos emitted in a weak decay are pure or mixed quantum states. The concept of mixed neutrinos has been with us for more than 20 years, having first been introduced by Maki et al (1) and by Pontecorvo (2) following demonstration in 1962 that more than one type (flavor) of neutrino existed. After having been dormant for some time, the interest in these issues wa...

  17. Physics at neutrino factories

    CERN Document Server

    Peach, Kenneth J

    2001-01-01

    There is increasing interest in using intense neutrino beams from a high-energy muon storage ring-the Neutrino Factory-to make precise measurements of the lepton mixing matrix, including the T-violating phase, as well as a diverse programme of other physics.

  18. A field-theoretical approach to entanglement in neutrino mixing and oscillations

    OpenAIRE

    Blasone, M.; Dell'Anno, F.; De Siena, S.; Illuminati, F.

    2014-01-01

    The phenomena of particle mixing and flavor oscillations in elementary particle physics can be addressed by the point of view of quantum information theory, and described in terms of multi-mode entanglement of single-particle states. In this paper we show that such a description can be extended to the domain of quantum field theory, where we uncover a fine structure of quantum correlations associated with multi-mode, multi-particle entanglement. By means of an entanglement measure based on th...

  19. Atmospheric Neutrinos

    OpenAIRE

    Takaaki Kajita

    2012-01-01

    Atmospheric neutrinos 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. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses...

  20. Eighty years of neutrino physics

    International Nuclear Information System (INIS)

    This is a pedagogical overview of neutrino physics from the invention of neutrino by Pauli in 1930 to the precise measurement of neutrino mass and mixing parameters via neutrino oscillation experiments in recent years. I have tried to pitch it at the level of undergraduate students, occasionally cutting corners to avoid the use of advanced mathematical tools. I hope it will be useful in introducing this exciting field to a broad group of young physicists. (author)

  1. Neutrino physics with JUNO

    Science.gov (United States)

    An, Fengpeng; An, Guangpeng; An, Qi; Antonelli, Vito; Baussan, Eric; Beacom, John; Bezrukov, Leonid; Blyth, Simon; Brugnera, Riccardo; Buizza Avanzini, Margherita; Busto, Jose; Cabrera, Anatael; Cai, Hao; Cai, Xiao; Cammi, Antonio; Cao, Guofu; Cao, Jun; Chang, Yun; Chen, Shaomin; Chen, Shenjian; Chen, Yixue; Chiesa, Davide; Clemenza, Massimiliano; Clerbaux, Barbara; Conrad, Janet; D'Angelo, Davide; De Kerret, Hervé; Deng, Zhi; Deng, Ziyan; Ding, Yayun; Djurcic, Zelimir; Dornic, Damien; Dracos, Marcos; Drapier, Olivier; Dusini, Stefano; Dye, Stephen; Enqvist, Timo; Fan, Donghua; Fang, Jian; Favart, Laurent; Ford, Richard; Göger-Neff, Marianne; Gan, Haonan; Garfagnini, Alberto; Giammarchi, Marco; Gonchar, Maxim; Gong, Guanghua; Gong, Hui; Gonin, Michel; Grassi, Marco; Grewing, Christian; Guan, Mengyun; Guarino, Vic; Guo, Gang; Guo, Wanlei; Guo, Xin-Heng; Hagner, Caren; Han, Ran; He, Miao; Heng, Yuekun; Hsiung, Yee; Hu, Jun; Hu, Shouyang; Hu, Tao; Huang, Hanxiong; Huang, Xingtao; Huo, Lei; Ioannisian, Ara; Jeitler, Manfred; Ji, Xiangdong; Jiang, Xiaoshan; Jollet, Cécile; Kang, Li; Karagounis, Michael; Kazarian, Narine; Krumshteyn, Zinovy; Kruth, Andre; Kuusiniemi, Pasi; Lachenmaier, Tobias; Leitner, Rupert; Li, Chao; Li, Jiaxing; Li, Weidong; Li, Weiguo; Li, Xiaomei; Li, Xiaonan; Li, Yi; Li, Yufeng; Li, Zhi-Bing; Liang, Hao; Lin, Guey-Lin; Lin, Tao; Lin, Yen-Hsun; Ling, Jiajie; Lippi, Ivano; Liu, Dawei; Liu, Hongbang; Liu, Hu; Liu, Jianglai; Liu, Jianli; Liu, Jinchang; Liu, Qian; Liu, Shubin; Liu, Shulin; Lombardi, Paolo; Long, Yongbing; Lu, Haoqi; Lu, Jiashu; Lu, Jingbin; Lu, Junguang; Lubsandorzhiev, Bayarto; Ludhova, Livia; Luo, Shu; Lyashuk, Vladimir; Möllenberg, Randolph; Ma, Xubo; Mantovani, Fabio; Mao, Yajun; Mari, Stefano M.; McDonough, William F.; Meng, Guang; Meregaglia, Anselmo; Meroni, Emanuela; Mezzetto, Mauro; Miramonti, Lino; Mueller, Thomas; Naumov, Dmitry; Oberauer, Lothar; Ochoa-Ricoux, Juan Pedro; Olshevskiy, Alexander; Ortica, Fausto; Paoloni, Alessandro; Peng, Haiping; Peng, Jen-Chieh; Previtali, Ezio; Qi, Ming; Qian, Sen; Qian, Xin; Qian, Yongzhong; Qin, Zhonghua; Raffelt, Georg; Ranucci, Gioacchino; Ricci, Barbara; Robens, Markus; Romani, Aldo; Ruan, Xiangdong; Ruan, Xichao; Salamanna, Giuseppe; Shaevitz, Mike; Sinev, Valery; Sirignano, Chiara; Sisti, Monica; Smirnov, Oleg; Soiron, Michael; Stahl, Achim; Stanco, Luca; Steinmann, Jochen; Sun, Xilei; Sun, Yongjie; Taichenachev, Dmitriy; Tang, Jian; Tkachev, Igor; Trzaska, Wladyslaw; van Waasen, Stefan; Volpe, Cristina; Vorobel, Vit; Votano, Lucia; Wang, Chung-Hsiang; Wang, Guoli; Wang, Hao; Wang, Meng; Wang, Ruiguang; Wang, Siguang; Wang, Wei; Wang, Yi; Wang, Yi; Wang, Yifang; Wang, Zhe; Wang, Zheng; Wang, Zhigang; Wang, Zhimin; Wei, Wei; Wen, Liangjian; Wiebusch, Christopher; Wonsak, Björn; Wu, Qun; Wulz, Claudia-Elisabeth; Wurm, Michael; Xi, Yufei; Xia, Dongmei; Xie, Yuguang; Xing, Zhi-zhong; Xu, Jilei; Yan, Baojun; Yang, Changgen; Yang, Chaowen; Yang, Guang; Yang, Lei; Yang, Yifan; Yao, Yu; Yegin, Ugur; Yermia, Frédéric; You, Zhengyun; Yu, Boxiang; Yu, Chunxu; Yu, Zeyuan; Zavatarelli, Sandra; Zhan, Liang; Zhang, Chao; Zhang, Hong-Hao; Zhang, Jiawen; Zhang, Jingbo; Zhang, Qingmin; Zhang, Yu-Mei; Zhang, Zhenyu; Zhao, Zhenghua; Zheng, Yangheng; Zhong, Weili; Zhou, Guorong; Zhou, Jing; Zhou, Li; Zhou, Rong; Zhou, Shun; Zhou, Wenxiong; Zhou, Xiang; Zhou, Yeling; Zhou, Yufeng; Zou, Jiaheng

    2016-03-01

    . Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ˜400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the {θ }23 mixing angle. Detection of the 7Be and 8B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with {10}-5 {{{eV}}}2\\lt {{Δ }}{m}412\\lt {10}-2 {{{eV}}}2 and a sufficiently large mixing angle {θ }14 could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the p\\to {K}++\\bar{ν } decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one

  2. Disentangling neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Andrew G. [Physics Department, Boston University, Boston, MA 02215 (United States)], E-mail: cohen@bu.edu; Glashow, Sheldon L. [Physics Department, Boston University, Boston, MA 02215 (United States)], E-mail: slg@bu.edu; Ligeti, Zoltan [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)], E-mail: ligeti@lbl.gov

    2009-07-13

    The theory underlying neutrino oscillations has been described at length in the literature. The neutrino state produced by a weak decay is usually portrayed as a linear superposition of mass eigenstates with, variously, equal energies or equal momenta. We point out that such a description is incorrect, that in fact, the neutrino is entangled with the other particle or particles emerging from the decay. We offer an analysis of oscillation phenomena involving neutrinos (applying equally well to neutral mesons) that takes entanglement into account. Thereby we present a theoretically sound proof of the universal validity of the oscillation formulae ordinarily used. In so doing, we show that the departures from exponential decay reported by the GSI experiment cannot be attributed to neutrino mixing. Furthermore, we demonstrate that the 'Moessbauer' neutrino oscillation experiment proposed by Raghavan, while technically challenging, is correctly and unambiguously describable by means of the usual oscillation formalae.

  3. Pseudo-Dirac Scenario for Neutrino Oscillations

    OpenAIRE

    Kobayashi, Makoto; Lim, C. S.

    2000-01-01

    We argue how pseudo-Dirac scenario for neutrinos leads to rich neutrino oscillation phenomena, including oscillation inside each generation. The pseudo-Dirac scenario is generalized by incorporating generation mixings and formulae for the various neutrino oscillations are derived. As the application we compare the formulae with the corresponding data. We find that observed pattern of mixings, such as almost maximal mixing in the atmospheric neutrino oscillation, is naturally explained in the ...

  4. Resurrection of large lepton number asymmetries from neutrino flavor oscillations

    CERN Document Server

    Barenboim, Gabriela; Park, Wan-Il

    2016-01-01

    We numerically solve the evolution equations of neutrino three-flavor density matrices, and show that, even if neutrino oscillations mix neutrino flavors, large lepton number asymmetries are still allowed in certain limits by Big Bang Nucleosynthesis (BBN).

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, N.G. [ed.

    1997-12-31

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

  7. Establishing atmospheric neutrino oscillations with Super-Kamiokande

    Science.gov (United States)

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

    2016-07-01

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

  8. Neutrino assisted gauge mediation

    International Nuclear Information System (INIS)

    Recent observation shows that the Higgs mass is at around 125 GeV while the prediction of the minimal supersymmetric standard model is below 120 GeV for stop mass lighter than 2 TeV unless the top squark has a maximal mixing. We consider the right-handed neutrino supermultiplets as messengers in addition to the usual gauge mediation to obtain sizeable trilinear soft parameters At needed for the maximal stop mixing. Neutrino messengers can explain the observed Higgs mass for stop mass around 1 TeV. Neutrino assistance can also generate charged lepton flavor violation including μ→e γ as a possible signature of the neutrino messengers. We consider the S4 discrete flavor model and show the relation of the charged lepton flavor violation, θ 13 of neutrino oscillation and the muon's g-2. (orig.)

  9. 中微子几何混合模型与轻子和重子数产生%Model of Geometric Neutrino Mixing and Leptogenesis

    Institute of Scientific and Technical Information of China (English)

    何小刚

    2006-01-01

    I report results obtained recently in collaboration with on neutrino mixing (hep-ph/0507217).Current neutrino oscillation data are consistent with the neutrino mixing angles taking values sin2 θ12 = 1/3,sin2 θ23 = 1/2, and sin2 θ13 = 0. We present a class of renormalizable gauge models which realize such a geometric mixing pattern naturally. These models, which are based on the non-Abelian discrete symmetry A4, place significant restrictions on the neutrino mass spectrum. It is shown that baryogenesis via leptogenesis occurs quite naturally, with a single phase (determined from neutrino oscillation data) appearing in leptonic asymmetry and in neutrinoless double beta decay.%在这一报告中将报告我和BABU教授合作的在hep-ph/0507217一文中有关中微子混合研究结果.目前中微子实验数据所决定的混合角可归结为几何混合状况:sin2θ12=1/3,sin2θ2a=1/2,和sin2θ13=0.我们在这一工作中建立了能实现这一几何混合的可重整化模型.模型以非阿贝尔非连续群A4为描述中微子不同代混合的对称性.这类模型对中微子质量有很强的限制.而且能很自然地由轻子数破坏产生重子不对称的实验观测值.很有趣的是这类模型中出现在轻子不守恒和无中微子双beta衰变中的相位是一样的.

  10. The Neutrino: Evidence of a Negative-Energy Vacuum State

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-04-01

    Full Text Available This note argues that the neutrino is a phonon packet that exists and propagates within the negative-energy Planck vacuum. Simple calculations connect the three neutrinos to their corresponding leptons and show: that the neutrino mass is a ficticious or effective mass; that the neutrino mass cannot be zero; that each of the three neutrinos has a unique mass that determines its velocity; and that flavor (neutrino-type mixing does not involve mass mixing.

  11. Some comments on high precision study of neutrino oscillations

    Science.gov (United States)

    Bilenky, S. M.

    2015-07-01

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

  12. 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...

  13. 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.

  14. Dimensional deconstruction and neutrino physics

    International Nuclear Information System (INIS)

    We present a simple observation for neutrino mixings and masses which arise naturally in dimensional deconstruction models. There are two essential ingredients of such models: (i) the presence of a symmetry mediated by the link fields which results in the neutrino mixings to be maximal; and (ii) a large deconstruction scale which gives rise to a small neutrino mass, similar in feature to the seesaw mechanism

  15. Dimensional Deconstruction and Neutrino Physics

    CERN Document Server

    Balaji, K R S

    2005-01-01

    We present a simple observation for neutrino mixings and masses which arises naturally in dimensional deconstruction models. There are two essential ingredients of such models: (i) the presence of a symmetry mediated by the link fields which results in the neutrino mixings to be maximal; and (ii) a deconstruction scale which for large values gives rise to a small neutrino mass, similar in feature to the seesaw mechanism.

  16. Radiative emission of neutrino pairs in atoms and light sterile neutrinos

    Directory of Open Access Journals (Sweden)

    D.N. Dinh

    2015-03-01

    Full Text Available The process of Radiative Emission of Neutrino Pair (RENP in atoms is sensitive to the absolute neutrino mass scale, the type of spectrum neutrino masses obey and the nature – Dirac or Majorana – of massive neutrinos. We analyse the possibility to test the hypothesis of existence of neutrinos with masses at the eV scale coupled to the electron in the weak charged lepton current in an RENP experiment. The presence of eV scale neutrinos in the neutrino mixing is associated with the existence of sterile neutrinos which mix with the active flavour neutrinos. At present there are a number of hints for active–sterile neutrino oscillations driven by Δm2∼1 eV2. We perform a detailed analysis of the RENP phenomenology within the “3+1” scheme with one sterile neutrino.

  17. 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.

  18. Neutrino telescopes

    CERN Document Server

    Carr, J

    2002-01-01

    This review presents the scientific objectives and status of Neutrino Telescope Projects. The science program of these projects covers: neutrino astronomy, dark matter searches and measurements of neutrino oscillations. The two neutrino telescopes in operation: AMANDA and BAIKAL will be described together with the ANTARES neutrino telescope being built in the Mediterranean. (18 refs).

  19. Geometric phase of neutrinos in matter and in magnetic field: differences between Dirac and Majorana neutrinos

    CERN Document Server

    Capolupo, A; Hiesmayr, B C; Vitiello, G

    2016-01-01

    We analize the non-cyclic geometric phase for neutrinos propagating in the matter and through a magnetic field. We find that the geometric phase and the total phase associated to the mixing phenomenon and to the neutrino spin rotation can represent a tool to distinguish between Dirac and Majorana neutrinos. Future experiments, based on interferometry, therefore could reveal the nature of neutrinos.

  20. Pseudo-Dirac neutrinos as a potential complete solution to the neutrino oscillation puzzle

    CERN Document Server

    Geiser, A

    1998-01-01

    A solution for the neutrino mass and mixing pattern is proposed which is compatible with all available experimental data on neutrino oscillations. This solution involves Majorana neutrinos of the pseudo-Dirac type, i.e. $m_{\\rm Majorana} \\ll m_{\\rm Dirac}$. The solar and atmospheric neutrino observations are mainly explained as $\

  1. Muon neutrino to electron neutrino oscillations in the MINOS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Toner, R. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Pawloski, G. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Whitehead, L. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2012-08-15

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

  2. High-energy neutrino oscillations in absorbing matter

    OpenAIRE

    Vadim A. NaumovU. & INFN, Ferrara

    2015-01-01

    The impact of neutrino mixing, refraction and absorption on high-energy neutrino propagation through a thick medium is studied using the MSW evolution equation with complex indices of refraction. It is found that, owing to the mixing with sterile neutrinos, the penetrability of active neutrinos may be many orders of magnitude larger than it would be in the absence of mixing. The effect is highly sensitive to changes in density and composition of the matter background as well as to neutrino en...

  3. Evaluation of neutrino masses from $m_{\\beta\\beta}$ values

    CERN Document Server

    Khrushchov, V V

    2008-01-01

    A neutrino mass matrix is considered under conditions of the CP invariance and the negligible reactor mixing $\\theta_{13}$ angle. Absolute mass values for three neutrinos are evaluated in normal and inverted hierarchy spectra on the ground of data for oscillation mixing neutrino parameters and effective neutrino mass entering into a probability of neutrinoless two beta decay $m_{\\beta\\beta}$ values.

  4. 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.

  5. Bruno Pontecorvo and Neutrino Oscillations

    Directory of Open Access Journals (Sweden)

    Samoil M. Bilenky

    2013-01-01

    Full Text Available I discuss briefly in this review, dedicated to the centenary of the birth of the great neutrino physicist Bruno Pontecorvo, the following ideas he proposed: (i the radiochemical method of neutrino detection; (ii the μ - e universality of the weak interaction; (iii the accelerator neutrino experiment which allowed to prove that muon and electron neutrinos are different particles (the Brookhaven experiment. I consider in some details Pontecorvo's pioneering idea of neutrino masses, mixing, and oscillations and the development of this idea by Pontecorvo, by Pontecorvo and Gribov, and by Pontecorvo and myself.

  6. Neutrinos: summary of new results

    International Nuclear Information System (INIS)

    After a short presentation of the neutrino mass-mixing parameters, the core of the paper will be devoted to the recent experimental results from SNO, KamLAND and K2K. As a conclusion, I will discuss possible CP violation measurements with neutrinos. The paper is structured as follows: 1 Neutrino Oscillations Physics; 2 New results in solar neutrinos; 2.1 The SNO experiment; 2.2 The KamLAND experiment; 4 Opening the road toward a measurement of neutrino CP violation?

  7. Review of neutrino mass measurements

    International Nuclear Information System (INIS)

    The current status of the experimental search for neutrino mass is reviewed, with emphasis on direct kinematic methods. New data on the /tau/ neutrino from the Argus collaboration have reduced the upper mass limit a factor of 2. The situation concerning the electron neutrino mass as measured in tritium beta decay is essentially unchanged from a year ago. Simpson and Hime report finding evidence for a 17-keV neutrino in the β decay of 35S. There may be evidence for neutrino mass and mixing in the SN1987a data. 62 refs., 4 figs

  8. Future Neutrino Oscillation Sensitivities for LBNE

    CERN Document Server

    Bass, Matthew; Wilson, Robert J

    2013-01-01

    The primary goal of the Long-Baseline Neutrino Experiment (LBNE) is to measure the neutrino mixing matrix parameters. The design, optimized to search for CP violation and to determine the neutrino mass hierarchy, includes a large $\\mathcal{O}(10$ kt) Liquid Argon Time Projection Chamber (LAr TPC) at 1300 km downstream of a wide-band neutrino beam. A brief introduction to the neutrino mixing parameters will be followed by a discussion of sensitivity study analysis methods and a summary of the results for LBNE. The studies include comparisons with the Tokai-to-Kamioka (T2K) and NuMI Off-axis electron-neutrino Appearance (NO$\

  9. Democratic Neutrino Paradigm

    Science.gov (United States)

    Zhuridov, Dmitry

    2014-03-01

    I will introduce a democratic neutrino theory, which sets the absolute scale of the neutrino masses at about 0.03 eV, and has only one free parameter in contrast to 7 (9) free parameters in the conventional model of Dirac (Majorana) neutrino masses and mixing. Taking into account the incoherence and matter effects, this democratic theory agrees with the atmospheric and solar neutrino data. Moreover the results of the reactor neutrino experiments with the baselines around 100 m can be better explained. I will also discuss the predictions of this theory for low energy beta decays, magnetic moments, and neutrinoless double beta decays. Supported in part by the U.S. Department of Energy under contract DE-FG02-12ER41825.

  10. 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.

  11. 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...

  12. Geometric Mean Neutrino Mass Relation

    Science.gov (United States)

    He, Xiao-Gang; Zee, A.

    Present experimental data from neutrino oscillations have provided much information about the neutrino mixing angles. Since neutrino oscillations only determine the mass squared differences Δ m2ij = m2i - m2j, the absolute values for neutrino masses mi, can not be determined using data just from oscillations. In this work we study implications on neutrino masses from a geometric mean mass relation m2 = √ {m1m_3} which enables one to determined the absolute masses of the neutrinos. We find that the central values of the three neutrino masses and their 2σ errors to be m1 = (1.58 ± 0.18)meV, m2 = (9.04 ± 0.42)meV, and m3 = (51.8 ± 3.5)meV. Implications for cosmological observation, beta decay and neutrinoless double beta decays are discussed.

  13. Neutrino Physics

    Science.gov (United States)

    Lederman, L. M.

    1963-01-09

    The prediction and verification of the neutrino are reviewed, together with the V A theory for its interactions (particularly the difficulties with the apparent existence of two neutrinos and the high energy cross section). The Brookhaven experiment confirming the existence of two neutrinos and the cross section increase with momentum is then described, and future neutrino experiments are considered. (D.C.W.)

  14. 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.

  15. 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.

  16. Vacuum Neutrino Oscillations of Solar Neutrinos and Lepton Mass Matrices

    CERN Document Server

    Tanimoto, M

    1999-01-01

    We consider the case that the solar neutrino deficit is due to the vacuum oscillation. The lepton mass matrices with nearly bi-maximal mixings are needed in order to explain both solar and atmospheric neutrino deficit. A texture with the symmetry of flavour democracy or $S_3$ has been investigated by taking account of the symmetry breaking terms of the charged lepton mass matrix. It is found that predicted mixings can be considerably changed from the neutrino mixings $\\sin^2 2\\th_\\odot\\simeq 1$ and $\\sin^2 2\\th_{atm}\\simeq 8/9$ at the symmetric limit. The correlation between $|U_{e3}|$ and $|U_{e1}U_{e2}^*|$ is also presented. The test of the model is discussed by focusing on the three flavor analyses in the solar neutrinos, atmospheric neutrinos and long baseline experiments.

  17. Four-Neutrino Oscillation Solutions of the Solar Neutrino Problem

    CERN Document Server

    Giunti, C; Peña-Garay, C

    2000-01-01

    We present an analysis of the neutrino oscillation solutions of the solar neutrino problem in the framework of four-neutrino mixing where a sterile neutrino is added to the three standard ones. We perform a fit to the full data set corresponding to the 825-day Super-Kamiokande data sample as well as to Chlorine, GALLEX and SAGE and Kamiokande experiments. In our analysis we use all measured total event rates as well as all Super-Kamiokande data on the zenith angle dependence and the recoil electron energy spectrum. We consider both transitions via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism as well as oscillations in vacuum (just-so) and find the allowed solutions for different values of the additional mixing angles. This framework permits transitions into active or sterile neutrinos controlled by the additional parameter $\\cos^2(\\vartheta_{23}) \\cos^2(\\vartheta_{24})$ . We discuss the maximum allowed values of this additional mixing parameter for the different solutions.

  18. Structure formation in a mixed dark matter model with decaying sterile neutrino: the 3.5 keV X-ray line and the Galactic substructure

    CERN Document Server

    Harada, Akira; Yoshida, Naoki

    2016-01-01

    We perform a set of cosmological simulations of structure formation in a mixed dark matter (MDM) model. Our model is motivated by the recently identified $3.5\\,{\\rm keV}$ X-ray line that can be explained by the decay of non-resonantly produced sterile neutrinos, if they account for $10$-$60\\%$ of the dark matter in the Universe. The non-resonantly produced sterile neutrino has sizable free-streaming length and hence behaves effectively as warm dark matter (WDM). Assuming the rest of dark matter is composed of some stable and cold particles, i.e. cold dark matter (CDM), we follow the coevolution of the CDM and WDM density perturbations. Specifically, we consider the models with the warm component fraction of $r_{\\rm warm}=0.25$ and $0.5$. Our MDM model predicts that the comoving Jeans length at the matter-radiation equality is close to that of the thermally produced warm dark matter model with particle mass $m_{\\rm WDM}=2.4\\,{\\rm keV}$ but that the suppression in the fluctuation power spectrum is weaker. We pe...

  19. High-energy neutrino oscillations in absorbing matter

    CERN Document Server

    Naumov, V A

    2002-01-01

    The impact of neutrino mixing, refraction and absorption on high-energy neutrino propagation through a thick medium is studied using the MSW evolution equation with complex indices of refraction. It is found that, owing to the mixing with sterile neutrinos, the penetrability of active neutrinos may be many orders of magnitude larger than it would be in the absence of mixing. The effect is highly sensitive to changes in density and composition of the matter background as well as to neutrino energy and mixing parameters. This may lead to observational consequences in neutrino astrophysics.

  20. Constraints on neutrino oscillations using 1258 days of Super-Kamiokande solar neutrino data.

    Science.gov (United States)

    Fukuda, S; Fukuda, Y; Ishitsuka, M; Itow, Y; Kajita, T; Kameda, J; Kaneyuki, K; Kobayashi, K; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Okada, A; Sakurai, N; Shiozawa, M; Suzuki, Y; Takeuchi, H; Takeuchi, Y; Toshito, T; Totsuka, Y; Yamada, S; Desai, S; Earl, M; Kearns, E; Messier, M D; Scholberg, K; Stone, J L; Sulak, L R; Walter, C W; Goldhaber, M; Barszczak, T; Casper, D; Gajewski, W; Kropp, W R; Mine, S; Liu, D W; Price, L R; Smy, M B; Sobel, H W; Vagins, M R; Ganezer, K S; Keig, W E; Ellsworth, R W; Tasaka, S; Kibayashi, A; Learned, J G; Matsuno, S; Takemori, D; Hayato, Y; Ishii, T; Kobayashi, T; Nakamura, K; Obayashi, Y; Oyama, Y; Sakai, A; Sakuda, M; Kohama, M; Suzuki, A T; Inagaki, T; Nakaya, T; Nishikawa, K; Haines, T J; Blaufuss, E; Dazeley, S; Lee, K B; Svoboda, R; Goodman, J A; Guillian, G; Sullivan, G W; Turcan, D; Habig, A; Hill, J; Jung, C K; Martens, K; Malek, M; Mauger, C; McGrew, C; Sharkey, E; Viren, B; Yanagisawa, C; Mitsuda, C; Miyano, K; Saji, C; Shibata, T; Kajiyama, Y; Nagashima, Y; Nitta, K; Takita, M; Yoshida, M; Kim, H I; Kim, S B; Yoo, J; Okazawa, H; Ishizuka, T; Etoh, M; Gando, Y; Hasegawa, T; Inoue, K; Ishihara, K; Maruyama, T; Shirai, J; Suzuki, A; Koshiba, M; Hatakeyama, Y; Ichikawa, Y; Koike, M; Nishijima, K; Fujiyasu, H; Ishino, H; Morii, M; Watanabe, Y; Golebiewska, U; Kielczewska, D; Boyd, S C; Stachyra, A L; Wilkes, R J; Young, K K

    2001-06-18

    We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.

  1. Phenomenological consequences of singlet neutrinos

    CERN Document Server

    Chang, L N; Ng, J N; Lay Nam Chang; Daniel Ng; John N Ng

    1994-01-01

    In this paper, we study the phenomenology of right-handed neutrino isosinglets. We consider the general situation where the neutrino masses are not necessarily given by $m_D^2/M$, where $m_D$ and $M$ are the Dirac and Majorana mass terms respectively. The consequent mixing between the light and heavy neutrinos is then not suppressed, and we treat it as an independent parameter in the analysis. It turns out that $\\mu-e$ conversion is an important experiment in placing limits on the heavy mass scale ($M$) and the mixing. Mixings among light neutrinos are constrained by neutrinoless double beta decay, as well as by solar and atmospheric neutrino experiments. Detailed one-loop calculations for lepton number violating vertices are provided.

  2. Detecting sterile neutrinos with KATRIN like experiments

    DEFF Research Database (Denmark)

    Riis, Anna Sejersen; Hannestad, Steen

    2011-01-01

    A sterile neutrino with mass in the eV range, mixing with bar nue, is allowed and possibly even preferred by cosmology and oscillation experiments. If such eV-mass neutrinos exist they provide a much better target for direct detection in beta decay experiments than the active neutrinos which...

  3. Solar models and solar neutrino oscillations

    OpenAIRE

    Bahcall, John N.; Peña Garay, Carlos

    2004-01-01

    We provide a summary of the current knowledge, theoretical and experimental, of solar neutrino fluxes and of the masses and mixing angles that characterize solar neutrino oscillations. We also summarize the principal reasons for doing new solar neutrino experiments and what we think may be learned from the future measurements.

  4. Physics Potential of Solar Neutrino Experiments

    OpenAIRE

    Balantekin, A. B.; Yuksel, H.

    2003-01-01

    We discuss the physics potential of the solar neutrino experiments i) To explore the parameter space of neutrino mass and mixings; ii) To probe the physics of the Sun; iii) To explore nuclear physics of the neutrino-target interactions. Examples are given for these three classes.

  5. Studies of Neutrino Oscillations at Reactors

    OpenAIRE

    Boehm, Felix

    2000-01-01

    Experiments with reactor neutrinos continue to shed light on our understanding of neutrino oscillations. We review some of the early decisive experiments. We then turn to the recent long baseline oscillation experiments at Palo Verde and Chooz which are leading to the conclusion that the atmospheric neutrino anomaly if attributed to oscillations does not involve an appreciable mixing with the $\\bar\

  6. Probing Extra Dimensions with Neutrino Oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Machado, P.A.N. [Instituto de Fisica, Universidade de Sao Paulo, C. P. 66.318, 05315-970 Sao Paulo (Brazil); Nunokawa, H. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, C. P. 38071, 22452-970 Rio de Janeiro (Brazil); Zukanovich Funchal, R., E-mail: zukanov@fma.if.usp.br [Instituto de Fisica, Universidade de Sao Paulo, C. P. 66.318, 05315-970 Sao Paulo (Brazil)

    2011-08-15

    We consider a model where sterile neutrinos can propagate in a large compactified extra dimension (a) giving rise to Kaluza-Klein (KK) modes and the Standard Model left-handed neutrinos are confined to a 4-dimensional spacetime brane. The KK modes mix with the standard neutrinos modifying their oscillation pattern. We examine current experiments in this framework obtaining stringent limits on a.

  7. Neutrino spectrum from theory and experiments

    Indian Academy of Sciences (India)

    Anjan S Joshipura

    2000-01-01

    The observed deficits in the solar and atmospheric neutrino fluxes along with the accelerator results on neutrino oscillations significantly constrain possible mass and mixing patterns among neutrinos. We discuss possible patterns emerging from the experimental results and review theoretical attempts to understand them.

  8. Atmospheric neutrinos and neutrino oscillations

    International Nuclear Information System (INIS)

    The results on the composition of atmospheric neutrinos interacting in underground detectors and on the rate of atmospheric muon neutrino interactions in the earth surrounding the detectors are reviewed. So far, systematic errors on the neutrino flux and on the electrons and muons neutrino interaction identifications are not yet reliable enough to prove that atmospheric neutrinos oscillate before being detected. (author) 22 refs., 5 figs

  9. Neutrino mass models

    Science.gov (United States)

    King, S. F.

    2004-02-01

    This is a review article about neutrino mass models, particularly see-saw models involving three active neutrinos that are capable of describing both the atmospheric neutrino oscillation data and the large mixing angle (LMA) MSW solar solution, which is now uniquely specified by recent data. We briefly review the current experimental status, show how to parametrize and construct the neutrino mixing matrix, and present the leading order neutrino Majorana mass matrices. We then introduce the see-saw mechanism and discuss a natural application of it to current data using the sequential dominance mechanism, which we compare with an early proposal for obtaining LMAs. We show how both the Standard Model and the Minimal Supersymmetric Standard Model may be extended to incorporate the see-saw mechanism and show how the latter case leads to the expectation of lepton flavour violation. The see-saw mechanism motivates models with additional symmetries such as unification and family symmetry models, and we tabulate some possible models before focusing on two particular examples based on SO(10) grand unification and either U(1) or SU(3) family symmetry as specific examples. This review contains extensive appendices that include techniques for analytically diagonalizing different types of mass matrices involving two LMAs and one small mixing angle, to leading order in the small mixing angle.

  10. Probing the Origin of Neutrino Masses and Mixings via Doubly Charged Scalars: Complementarity of the Intensity and the Energy Frontiers

    CERN Document Server

    Geib, Tanja; Merle, Alexander; No, Jose Miguel; Panizzi, Luca

    2015-01-01

    We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar $S^{++}$ and its antiparticle $S^{--}$. In particular we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.

  11. Probing the origin of neutrino masses and mixings via doubly charged scalars: Complementarity of the intensity and the energy frontiers

    Science.gov (United States)

    Geib, Tanja; King, Stephen F.; Merle, Alexander; No, Jose Miguel; Panizzi, Luca

    2016-04-01

    We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar S++ and its antiparticle S-- . In particular, we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.

  12. Non-unitary neutrino propagation from neutrino decay

    International Nuclear Information System (INIS)

    Neutrino propagation in space-time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature

  13. 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.

  14. Non-unitary neutrino propagation from neutrino decay

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Berryman

    2015-03-01

    Full Text Available Neutrino propagation in space–time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature.

  15. Prospects for Neutrino Spin Coherence in Supernovae

    CERN Document Server

    Tian, James

    2016-01-01

    We present neutrino bulb model simulations of majorana neutrino coherent spin transformation (i.e., neutrino-antineutrino transformation) for conditions corresponding to the neutronization burst epoch of an O-Ne-Mg core collapse supernova. Significant neutrino spin transformation, in e.g. the neutronization burst, could alter the fluence of neutrinos and antineutrinos in a way which is potentially detectable for a galactic core collapse supernova. Our calculations for the first time treat geometric dilution in the spin evolution of the neutrinos and combine two-flavor and three-flavor neutrino flavor evolution with spin mixing physics. We find that significant spin transformations can occur, but only with an electron fraction profile which facilitates adiabatic conditions for the spin-channel resonance. Using our adopted parameters of neutrino energy spectra, luminosity, density and electron fraction profiles, our calculations require an unrealistically large neutrino rest mass to sustain the spin transformat...

  16. Relic neutrino decoupling including flavour oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Mangano, Gianpiero [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Department of Physics, Syracuse University, Syracuse, NY 13244-1130 (United States); Miele, Gennaro [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Pastor, Sergio [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Ed. Institutos de Investigacion, Apdo. 22085, E-46071 Valencia (Spain)]. E-mail: pastor@ific.uv.es; Pinto, Teguayco [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Ed. Institutos de Investigacion, Apdo. 22085, E-46071 Valencia (Spain); Pisanti, Ofelia [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Serpico, Pasquale D. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Munich (Germany)

    2005-11-21

    In the early universe, neutrinos are slightly coupled when electron-positron pairs annihilate transferring their entropy to photons. This process originates non-thermal distortions on the neutrino spectra which depend on neutrino flavour, larger for {nu}{sub e} than for {nu}{sub {mu}} or {nu}{sub {tau}}. We study the effect of three-neutrino flavour oscillations on the process of neutrino decoupling by solving the momentum-dependent kinetic equations for the neutrino spectra. We find that oscillations do not essentially modify the total change in the neutrino energy density, giving N{sub eff}=3.046 in terms of the effective number of neutrinos, while the small effect over the production of primordial {sup 4}He is increased by O(20%), up to 2.1x10{sup -4}. These results are stable within the presently favoured region of neutrino mixing parameters.

  17. Sterile neutrino dark matter and core-collapse supernovae

    CERN Document Server

    Mathews, Grant J; Hidaka, Jun; Kajino, Toshitaka

    2016-01-01

    We have explored the impact of sterile neutrino dark matter on core-collapse supernova explosions. We have included oscillations between electron neutrinos or mixed $\\mu,\\tau$ neutrinos and right-handed sterile neutrinos into a supernova model. We have chosen sterile neutrino masses and mixing angles that are consistent with sterile neutrino dark matter candidates as indicated by recent x-ray flux measurements. Using these simulations, we have explored the impact of sterile neutrinos on the core bounce and shock reheating. We find that, for ranges of sterile neutrino mass and mixing angle consistent with most dark matter constraints, the shock energy can be significantly enhanced and even a model that does not explode can be made to explode. In addition, we have found that the presence of a sterile neutrino may lead to detectable changes in the observed neutrino luminosities.

  18. Embedding A4 into SU(3)xU(1) flavor symmetry: Large neutrino mixing and fermion mass hierarchy in SO(10) GUT

    CERN Document Server

    Bazzocchi, F; Picariello, M; Torrente-Lujan, E

    2008-01-01

    We present a common explanation of the fermion mass hierarchy and the large lepton mixing angles in the context of a grand unified flavor and gauge theory (GUTF). Our starting point is a SU(3)xU(1) flavor symmetry and a SO(10) GUT, a basic ingredient of our theory which plays a major role is that two different breaking pattern of the flavor symmetry are at work. On one side, the dynamical breaking of SU(3)xU(1) flavor symmetry into U(2)xZ_3 explains why one family is much heavier than the others. On the other side, an explicit symmetry breaking of SU(3) into a discrete flavor symmetry leads to the observed tribimaximal mixing for the leptons. We write an explicit model where this discrete symmetry group is A4. Naturalness of the charged fermion mass hierarchy appears as a consequence of the continuous SU(3) flavor symmetry. Moreover, the same discrete A4-GUT invariant operators are the root of the large lepton mixing, small Cabibbo angle, and neutrino masses.

  19. Dark energy and neutrino model in SUSY

    International Nuclear Information System (INIS)

    We consider a Mass Varying Neutrinos (MaVaNs) model in supersymmetric theory. The model includes effects of supersymmetry breaking transmitted by the gravitational interaction from the hidden sector, in which supersymmetry was broken, to the dark energy sector. Then evolutions of the neutrino mass and the equation of state parameter of the dark energy are presented in the model. It is remarked that only the mass of a sterile neutrino is variable in the case of the vanishing mixing between the left-handed and a sterile neutrino on cosmological time scale. The finite mixing makes the mass of the left-handed neutrino variable. (author)

  20. Neutrino astrophysics

    International Nuclear Information System (INIS)

    A general overview of neutrino physics and astrophysics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important to establish if neutrinos are massive and introduce the main scenarios to provide them a mass. The present bounds and the positive indications in favor of non-zero neutrino masses are discussed, including the recent results on atmospheric and solar neutrinos. The major role that neutrinos play in astrophysics and cosmology is illustrated. (author)

  1. Solar and Supernova Constraints on Cosmologically Interesting Neutrinos

    CERN Document Server

    Haxton, W

    1997-01-01

    The sun and core-collapse supernovae produce neutrino spectra that are sensitive to the effects of masses and mixing. Current results from solar neutrino experiments provide perhaps our best evidence for such new neutrino physics, beyond the standard electroweak model. I discuss this evidence as well as the limited possibilities for more conventional explanations. If the resolution of the solar neutrino problem is $\

  2. Short-baseline reactor neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Mariani, C. [Department of Physics, Columbia University, New York, NY 10027 (United States)

    2011-08-15

    The neutrino mixing angle {theta}13 is currently a high-priority topic in the field of neutrino physics, with three different reactor neutrino experiments under way, searching for neutrino oscillations induced by this angle. A description of the reactor experiments searching for a non-zero value of {theta}13 is given, together with a discussion of their sensitivity within the next few years.

  3. Magnus approximation in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Acero, Mario A; Aguilar-Arevalo, Alexis A; D' Olivo, J C, E-mail: mario.acero@nucleares.unam.mx [Instituto de Ciencias Nucleares, Departamento de Fisica de Altas Energias, Universidad Nacional Autonoma de Mexico (ICN-UNAM) (Mexico); Apdo. Postal 70-543, Mexico, D.F. 04510 (Mexico)

    2011-04-01

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

  4. Neutrino Self-Interactions

    CERN Document Server

    Hasenkamp, Jasper

    2016-01-01

    We propose a theory that equips the active neutrinos with interactions among themselves that are at least three orders of magnitude stronger than the weak interaction. We introduce an Abelian gauge group $U(1)_x$ with vacuum expectation value $v_x \\lesssim \\mathcal{O}(100 \\textrm{ MeV})$. An asymmetric mass matrix implements the active neutrinos as massless mass eigenstates carrying "effective" charges. To stabilize $v_x$, supersymmetry breaking is mediated via loops to the additional sector with the only exception of xHiggs terms. No Standard Model interaction eigenstate carries $U(1)_x$ charge. Thus the dark photon's kinetic mixing is two-loop suppressed.With only simple and generic values of dimensionless parameters, our theory might explain the high-energy neutrino spectrum observed by IceCube including the PeV neutrinos. We comment on the imposing opportunity to incorporate a self-interacting dark matter candidate.

  5. Measurement of Atmospheric Neutrino Oscillations with the ANTARES Neutrino Telescope

    CERN Document Server

    Adrian-Martinez, S; Albert, A; Andre, M; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Astraatmadja, T; Aubert, J -J; Baret, B; Basa, S; Bertin, V; Biagi, S; Bigongiari, C; Bogazzi, C; Bou-Cabo, M; Bouhou, B; Bouwhuis, M C; Brunner, J; Busto, J; Capone, A; Carloganu, C; Carr, J; Cecchini, S; Charif, Z; Charvis, Ph; Chiarusi, T; Circella, M; Coniglione, R; Core, L; Costantini, H; Coyle, P; Creusot, A; Curtil, C; De Bonis, G; Decowski, M P; Dekeyser, I; Deschamps, A; Distefano, C; Donzaud, C; Dornic, D; Dorosti, Q; Drouhin, D; Eberl, T; Emanuele, U; Enzenhoefer, A; Ernenwein, J -P; Escoffier, S; Fehn, K; Fermani, P; Ferri, M; Ferry, S; Flaminio, V; Folger, F; Fritsch, U; Fuda, J -L; Galata, S; Gay, P; Geyer, K; Giacomelli, G; Giordano, V; Gleixner, A; Gomez-Gonzalez, J P; Graf, K; Guillard, G; Hallewell, G; Hamal, M; van Haren, H; Heijboer, A J; Hello, Y; Hernandez-Rey, J J; Herold, B; Hoessl, J; Hsu, C C; de Jong, M; Kadler, M; Kalekin, O; Kappes, A; Katz, U; Kavatsyuk, O; Kooijman, P; Kopper, C; Kouchner, A; Kreykenbohm, I; Kulikovskiy, V; Lahmann, R; Lambard, G; Larosa, G; Lattuada, D; Lefevre, D; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Louis, F; Mangano, S; Marcelin, M; Margiotta, A; Martinez-Mora, J A; Meli, A; Montaruli, T; Morganti, M; Moscoso, L; Motz, H; Neff, M; Nezri, E; Palioselitis, D; Pavalas, G E; Payet, K; Petrovic, J; Piattelli, P; Popa, V; Pradier, T; Presani, E; Racca, C; Reed, C; Riccobene, G; Richardt, C; Richter, R; Riviere, C; Robert, A; Roensch, K; Rostovtsev, A; Ruiz-Rivas, J; Rujoiu, M; Russo, G V; Samtleben, D F E; Sanchez-Losa, A; Sapienza, P; Schmid, J; Schnabel, J; Schoeck, F; Schuller, J -P; Schuessler, F; Seitz, T; Shanidze, R; Simeone, F; Spies, A; Spurio, M; Steijger, J J M; Stolarczyk, Th; Taiuti, M; Tamburini, C; Trovato, A; Vallage, B; Vallee, C; Van Elewyck, V; Vecchi, M; Vernin, P; Visser, E; Wagner, S; Wijnker, G; Wilms, J; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zuniga, J

    2012-01-01

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximum mixing, a mass difference of $\\Delta m_{32}^2=(3.1\\pm 0.9)\\cdot 10^{-3}$ eV$^2$ is obtained, in good agreement with the world average value.

  6. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    International Nuclear Information System (INIS)

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of Δm322=(3.1±0.9)⋅10-3 eV2 is obtained, in good agreement with the world average value.

  7. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Adrian-Martinez, S. [Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Universitat Politecnica de Valencia, C/ Paranimf 1, 46730 Gandia (Spain); Al Samarai, I. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Albert, A. [GRPHE - Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit, BP 50568, 68008 Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposicio, 08800 Vilanova i la Geltru, Barcelona (Spain); Anghinolfi, M. [INFN - Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Anton, G. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Anvar, S. [Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service d' Electronique des Detecteurs et d' Informatique, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Ardid, M. [Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Universitat Politecnica de Valencia, C/ Paranimf 1, 46730 Gandia (Spain); Astraatmadja, T. [Nikhef, Science Park, Amsterdam (Netherlands); Aubert, J.-J. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); and others

    2012-08-14

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of {Delta}m{sub 32}{sup 2}=(3.1{+-}0.9) Dot-Operator 10{sup -3} eV{sup 2} is obtained, in good agreement with the world average value.

  8. Atmospheric Neutrino Oscillations in Antares

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, J.

    2013-04-15

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximum mixing, a mass difference of Δm{sub 32}{sup 2}=(3.1±0.9)⋅10{sup −3}eV{sup 2} is obtained, in good agreement with the world average value.

  9. Neutrino astronomy

    International Nuclear Information System (INIS)

    In recent years, there has been considerable discussion on the field called neutrino astronomy which represents exciting prospect in that it deals with the radiations which are distinct from electromagnetic spectra. Because of the unique, enormously long interaction mean free path of neutrinos, this field can in principle give extremely valuable complementary information about the universe, in particular about the conditions in the core of the sun and the energy balance and extent of the galaxy. Remarkable difference is observed when outlining of the development of neutrino astronomy is attempted in a manner similar to that for radio astronomy. The development on solar neutrinos, calculation of solar neutrino flux, solar neutrino search experiments, efforts to resolve the discrepancy between theory and experiment concerning the neutrinos from the sun, chemistry consideration, nuclear physics problems, astrophysical calculation, neutrino physics and other physical accomplishments are reviewed in the report. (Iwase, T.)

  10. Overview of the T2K long baseline neutrino oscillation experiment

    CERN Document Server

    Le, Trung

    2009-01-01

    Neutrino oscillations were discovered by atmospheric and solar neutrino experiments, and have been confirmed by experiments using neutrinos from accelerators and nuclear reactors. It has been found that there are large mixing angles in the $\

  11. Dependence of the leptonic decays of H{sup ±} on the neutrino mixing angles θ{sub 13} and θ{sub 23} in models with neutrinophilic charged scalars

    Energy Technology Data Exchange (ETDEWEB)

    Akeroyd, A.G., E-mail: a.g.akeroyd@soton.ac.uk [School of Physics and Astronomy, University of Southampton Highfield, Southampton SO17 1BJ (United Kingdom); Particle Physics Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Moretti, S., E-mail: S.Moretti@soton.ac.uk [School of Physics and Astronomy, University of Southampton Highfield, Southampton SO17 1BJ (United Kingdom); Particle Physics Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Sugiyama, Hiroaki, E-mail: sugiyama@cc.kyoto-su.ac.jp [Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

    2014-01-20

    In the Higgs Triplet Model and the neutrinophilic Two-Higgs-Doublet Model the observed neutrinos obtain mass from a vacuum expectation value which is much smaller than the vacuum expectation value of the Higgs boson in the Standard Model. Both models contain a singly charged Higgs boson (H{sup ±}) whose Yukawa coupling is directly related to the neutrino mass (i.e. a “neutrinophilic charged Higgs”). The partial decay widths of H{sup ±} into a charged lepton and a neutrino (H{sup ±}→ℓ{sup ±}ν) depend identically on the neutrino masses and mixings in the two models. We quantify the impact of the recent measurement of sin{sup 2}2θ{sub 13}, which plays a crucial role in determining the magnitude of the branching ratio of H{sup ±}→e{sup ±}ν for the case of a normal neutrino mass ordering if the lightest neutrino mass m{sub 0}<10{sup −3} eV. We also discuss the sizeable dependence of H{sup ±}→μ{sup ±}ν and H{sup ±}→τ{sup ±}ν on sin{sup 2}θ{sub 23}, which would enable information to be obtained on sin{sup 2}θ{sub 23} and the sign of Δm{sub 31}{sup 2} if these decays are measured. Such information would help neutrino oscillation experiments to determine the CP-violating phase δ.

  12. Neutrino Astrophysics

    OpenAIRE

    Haxton, W. C.

    2000-01-01

    A general overview of neutrino physics and astrophysics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important to establish if neutrinos are massive and introduce the main scenarios to provide them a mass. The present bounds and the positive indications in favor of non-zero neutrino masses are discussed, including the recent results on atmospheric an...

  13. Neutrino Physics

    CERN Document Server

    Romanino, Andrea

    2012-01-01

    These lectures aim at providing a pedagogical overview of neutrino physics. We will mostly deal with standard neutrinos, the ones that are part of the Standard Model of particle physics, and with their standard dynamics, which is enough to understand in a coherent picture most of the rich data available. After introducing the basic theoretical framework, we will illustrate the experimental determination of the neutrino parameters and their theoretical implications, in particular for the origin of neutrino masses.

  14. A Novel Approach In The Detection Of Muon Neutrino To Tau Neutrino Oscillation From Extragalactic Neutrinos

    CERN Document Server

    Iyer, S R

    2001-01-01

    A novel approach is proposed for studying the νμ → ν τ oscillation and detection of extragalactic neutrinos. Active Galactic Nuclei (AGN), Gamma Ray Bursters (GRB) and Topological Defects are believed to be sources of ultrahigh energy νμ and ντ. These astrophysical sources provide a long baseline of 100Mpc, or more, for possible detection of νμ → ντ oscillation with mixing parameter Δm2 down to 10 −17 eV2, many orders of magnitude below the current accelerator experiments. The propagation characteristics of upward going muon and tau neutrinos is studied to show that high energy tau neutrinos cascade down in energy as they propagate through the Earth, producing an enhancement of the incoming tau neutrino flux in the low energy region. By contrast, high energy muon neutrinos get attenuated as they traverse the Earth. It is observed that the relative steepness of the incoming neutrino flux...

  15. Neutrino properties

    CERN Document Server

    Valle, José W F

    1996-01-01

    A brief sketch is made of the present observational status of neutrino properties, with emphasis on the hints from solar and atmospheric neutrinos, as well as cosmological data on the amplitude of primordial density fluctuations. Implications of neutrino mass in particle accelerators, astrophysics and cosmology are discussed.

  16. Neutrino Radar

    CERN Document Server

    Panigrahi, P K

    2002-01-01

    We point out that with improving our present knowledge of experimental neutrino physics it will be possible to locate nuclear powered vehicles like submarines, aircraft carriers and UFOs and detect nuclear testing. Since neutrinos cannot be shielded, it will not be possible to escape these detection. In these detectors it will also be possible to perform neutrino oscillation experiments during any nuclear testing.

  17. Entanglement in neutrino oscillations

    International Nuclear Information System (INIS)

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

  18. Entanglement in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, M.; Dell' Anno, F.; De Siena, S.; Illuminati, F. [Universita degli Studi di Salerno Via Ponte don Melillon, Dipt. di Matematica e Informatica, Fisciano SA (Italy); INFN Sezione di Napoli, Gruppo collegato di Salerno - Baronissi SA (Italy); Dell' Anno, F.; De Siena, S.; Illuminati, F. [CNR-INFM Coherentia - Napoli (Italy); Blasone, M. [ISI Foundation for Scientific Interchange, Torino (Italy)

    2009-03-15

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

  19. Neutrino spin-flavor oscillations derived from the mass basis

    CERN Document Server

    Fabbricatore, Riccardo; Studenikin, Alexander

    2016-01-01

    We consider neutrino mixing and oscillations in presence of an arbitrary constant magnetic field with nonzero transversal $B_{\\perp}$ and longitudinal $B_{\\parallel}$ components with respect to the direction of neutrino propagation. The electromagnetic interaction of neutrinos is determined by diagonal and transition neutrino magnetic moments that are introduced for the neutrino mass states. Explicit expressions for the effective neutrino diagonal and transition magnetic moments for the flavor basis in terms of these values for the mass states are obtained. The effective evolution Hamiltonian for the flavor neutrino and the corresponding oscillation probability are derived. The role of the longitudinal magnetic field component is examined. In particular, it is shown that: 1) $B_{\\parallel}$ coupled to the corresponding magnetic moments shifts the neutrino energy, and 2) in case of nonvanishing neutrino transition magnetic moments $B_{\\parallel}$ produces an additional mixing between neutrino states, both in t...

  20. Sterile neutrino oscillations in core-collapse supernova simulations

    CERN Document Server

    Warren, MacKenzie L; Mathews, Grant; Hidaka, Jun; Kajino, Toshitaka

    2014-01-01

    We have made core-collapse supernova simulations that allow oscillations between electron neutrinos (or their anti particles) with right-handed sterile neutrinos. We have considered a range of mixing angles and sterile neutrino masses including those consistent with sterile neutrinos as a dark matter candidate. We examine whether such oscillations can impact the core bounce and shock reheating in supernovae. We identify the optimum ranges of mixing angles and masses that can dramatically enhance the supernova explosion by efficiently transporting electron anti-neutrinos from the core to behind the shock where they provide additional heating leading to much larger explosion kinetic energies. We show that an interesting oscillation in the neutrino luminosity develops due to a cycle of depletion of the neutrino density by conversion to sterile neutrinos that shuts off the conversion, followed by a replenished neutrino density as neutrinos transport through the core.

  1. Leptogenesis with Almost Degenerate Majorana Neutrinos

    CERN Document Server

    Fujii, M; Yanagida, T; Fujii, Masaaki

    2002-01-01

    We investigate the leptogenesis with almost degenerate neutrinos, in the framework of democratic mass matrix, which naturally explains the large mixing angles for neutrino oscillations as well as quark masses and mixing matrix. We find that the baryon asymmetry in the present universe is explained via the decays of right-handed neutrinos produced nonthermally by the inflaton decay. The model predicts neutrinoless double beta decays accessible in near future experiments.

  2. Phenomenological Consequences of Heavy Right Handed Neutrinos

    OpenAIRE

    Rayyan, Saifuddin Ramadan

    2007-01-01

    The discovery of neutrino mixing provides the possibility of a non vanishing CP violating phase in the neutrino mixing matrix. CP violation in the leptonic sector can be large enough to explain the matter-antimatter asymmetry in the universe. An indirect probe of CP violation is the experimental measurement of Electric Dipole Moment (EDM). CP violation has been discovered in the quark sector,but it contributes to lepton EDM at the 3-loop level. Neutrino masses can...

  3. Solar neutrinos and neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Maltoni, Michele [Universidad Autonoma de Madrid, Instituto de Fisica Teorica UAM/CSIC, Madrid (Spain); Smirnov, Alexei Yu. [Max-Planck Institute for Nuclear Physics, Heidelberg (Germany); ICTP, Trieste (Italy)

    2016-04-15

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

  4. Supernova Neutrino Nucleosynthesis of Light Elements with Neutrino Oscillations

    CERN Document Server

    Yoshida, T; Yokomakura, H; Kimura, K; Takamura, A; Hartmann, D H

    2006-01-01

    Light element synthesis in supernovae through neutrino-nucleus interactions, i.e., the nu-process, is affected by neutrino oscillations in the supernova environment. There is a resonance of 13-mixing in the O/C layer, which increases the rates of charged-current nu-process reactions in the outer He-rich layer. The yields of 7Li and 11B increase by about a factor of 1.9 and 1.3, respectively, for a normal mass hierarchy and an adiabatic 13-mixing resonance, compared to those without neutrino oscillations. In the case of an inverted mass hierarchy and a non-adiabatic 13-mixing resonance, the increase in the 7Li and 11B yields is much smaller. Observations of the 7Li/11B ratio in stars showing signs of supernova enrichment could thus provide a unique test of neutrino oscillations and constrain their parameters and the mass hierarchy.

  5. Supernova neutrino nucleosynthesis of light elements with neutrino oscillations.

    Science.gov (United States)

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

    2006-03-10

    Light element synthesis in supernovae through neutrino-nucleus interactions, i.e., the v process, is affected by neutrino oscillations in the supernova environment. There is a resonance of 13-mixing in the O/C layer, which increases the rates of charged-current -process reactions in the outer He-rich layer. The yields of 7Li and 11B increase by about a factor of 1.9 and 1.3, respectively, for a normal mass hierarchy and an adiabatic 13-mixing resonance, compared to those without neutrino oscillations. In the case of an inverted mass hierarchy and a nonadiabatic 13-mixing resonance, the increase in the 7Li and 11B yields is much smaller. Observations of the 7Li/11B ratio in stars showing signs of supernova enrichment could thus provide a unique test of neutrino oscillations and constrain their parameters and the mass hierarchy.

  6. Neutrino Factory

    CERN Document Server

    Bogomilov, M; Tsenov, R; Dracos, M; Bonesini, M; Palladino, V; Tortora, L; Mori, Y; Planche, T; Lagrange, J  B; Kuno, Y; Benedetto, E; Efthymiopoulos, I; Garoby, R; Gilardoini, S; Martini, M; Wildner, E; Prior, G; Blondel, A; Karadzhow, Y; Ellis, M; Kyberd, P; Bayes, R; Laing, A; Soler, F  J  P; Alekou, A; Apollonio, M; Aslaninejad, M; Bontoiu, C; Jenner, L  J; Kurup, A; Long, K; Pasternak, J; Zarrebini, A; Poslimski, J; Blackmore, V; Cobb, J; Tunnell, C; Andreopoulos, C; Bennett, J  R  J; Brooks, S; Caretta, O; Davenne, T; Densham, C; Edgecock, T  R; Fitton, M; Kelliher, D; Loveridge, P; McFarland, A; Machida, S; Prior, C; Rees, G; Rogers, C; Rooney, M; Thomason, J; Wilcox, D; Booth, C; Skoro, G; Back, J  J; Harrison, P; Berg, J  S; Fernow, R; Gallardo, J  C; Gupta, R; Kirk, H; Simos, N; Stratakis, D; Souchlas, N; Witte, H; Bross, A; Geer, S; Johnstone, C; Mokhov, N; Neuffer, D; Popovic, M; Strait, J; Striganov, S; Morfín, J  G; Wands, R; Snopok, P; Bogacz, S  A; Morozov, V; Roblin, Y; Cline, D; Ding, X; Bromberg, C; Hart, T; Abrams, R  J; Ankenbrandt, C  M; Beard, K  B; Cummings, M  A  C; Flanagan, G; Johnson, R  P; Roberts, T  J; Yoshikawa, C  Y; Graves, V  B; McDonald, K  T; Coney, L; Hanson, G

    2014-01-01

    The properties of the neutrino provide a unique window on physics beyond that described by the standard model. The study of subleading effects in neutrino oscillations, and the race to discover CP-invariance violation in the lepton sector, has begun with the recent discovery that $\\theta_{13} > 0$. The measured value of $\\theta_{13}$ is large, emphasizing the need for a facility at which the systematic uncertainties can be reduced to the percent level. The neutrino factory, in which intense neutrino beams are produced from the decay of muons, has been shown to outperform all realistic alternatives and to be capable of making measurements of the requisite precision. Its unique discovery potential arises from the fact that only at the neutrino factory is it practical to produce high-energy electron (anti)neutrino beams of the required intensity. This paper presents the conceptual design of the neutrino factory accelerator facility developed by the European Commission Framework Programme 7 EURO$\

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

    Energy Technology Data Exchange (ETDEWEB)

    Soln, Josip [Army Research Laboratory (ret.), JZS Phys-Tech, Vienna, VA 22182 (United States)], E-mail: soln.phystech@cox.net

    2009-08-15

    For the electroweak interactions, the massive neutrino perturbative kinematical procedure is developed in the massive neutrino Fock space. The perturbation expansion parameter is the ratio of neutrino mass to its energy. This procedure, within the Pontecorvo-Maki-Nakagawa-Sakata (PMNS)-modified electroweak Lagrangian, calculates the cross-sections with the new neutrino energy projection operators in the massive neutrino Fock space, resulting in the dominant Lorentz invariant standard model massless flavor neutrino cross-sections. As a consequence of the kinematical relations between the massive and massless neutrinos, some of the neutrino oscillation cross-sections are Lorentz invariance violating. But all these oscillating cross-sections, some of which violate the flavor conservation, being proportional to the squares of neutrino masses are practically unobservable in the laboratory. However, these neutrino oscillating cross-sections are consistent with the original Pontecorvo neutrino oscillating transition probability expression at short time (baseline), as presented by Dvornikov. From these comparisons, by mimicking the time dependence of the original Pontecorvo neutrino oscillating transition probability, one can formulate the dimensionless neutrino intensity-probability I, by phenomenologically extrapolating the time t, or, equivalently the baseline distance L away from the collision point for the oscillating differential cross-section. For the incoming neutrino of 10 MeV in energy and neutrino masses from Fritzsch analysis with the neutrino mixing matrix of Harrison, Perkins and Scott, the baseline distances at the first two maxima of the neutrino intensity are L{approx_equal}281 and 9279 km. The intensity I at the first maximum conserves the flavor, while at the second maximum, the intensities violate the flavor, respectively, in the final and initial state. At the end some details are given as to how one should be able to verify experimentally these

  8. 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.

  9. Expectation values of flavor-neutrino numbers with respect to neutrino-source hadron states --Neutrino oscillations and decay probabilities--

    CERN Document Server

    Fujii, Kanji

    2014-01-01

    On the basis of quantum field theory, we consider a unified description of various processes accompanied by neutrinos, namely weak decays and oscillation processes. The structures of the expectation values of flavor-neutrino numbers with respect to neutrino-source hadron state are investigated. Due to the smallness of neutrino masses, we naturally obtain the old (i.e. pre-mixing) formulas of decay probabilities. Together, it is shown that the oscillation formulas, similar to the usual ones, are applied irrespectively of the details of neutrino-producing processes. The derived oscillation formulas are the same in form as the usually used ones except for the oscillation length.

  10. A review of the impact of sterile neutrino dark matter on core-collapse supernovae

    CERN Document Server

    Warren, MacKenzie; Meixner, Matthew; Hidaka, Jun; Kajino, Toshitaka

    2016-01-01

    We review the impact of sterile neutrino dark matter on core-collapse supernova explosions. We summarize various oscillations between electron neutrinos or mixed $\\mu-\\tau$ neutrinos and right-handed sterile neutrinos that have been studied within a supernova model. In particular, we consider sterile neutrino masses and mixing angles that are consistent with sterile neutrino dark matter candidates as indicated by recent x-ray flux measurements. We review how mixing between electron neutrinos and sterile neutrinos can significantly enhance the shock energy, and even a model that does not explode can be made to explode by this mechanism. However, the mixing between $\\mu-\\tau$ neutrinos and sterile neutrinos does not significantly alter the explosion and has little effect on the neutrino luminosities at early times.

  11. Liquid argon neutrino detectors

    CERN Document Server

    Battistoni, G

    2001-01-01

    The liquid argon imaging technique, as proposed for the ICARUS detector, offers the possibility to perform complementary and simultaneous measurements of neutrinos, as those of CERN to Gran Sasso beam (CNGS) and those from cosmic ray events. For the currently allowed values of the Super-Kamiokande results, the combination of both CNGS and atmospheric data will provide a precise determination of the oscillation parameters. Since one can observe and unambiguously identify nu /sub e/, nu /sub mu / and nu /sub tau / components, this technology allows to explore the full (3*3) mixing matrix. The same class of detector can be proposed for high precision measurements at a neutrino factory. (3 refs).

  12. Quasi-Degenerate Neutrino Masses with Normal and Inverted Hierarchy

    CERN Document Server

    Francis, Ng K

    2012-01-01

    The effects of CP-phases on the three absolute quasi-degenerate Majorana neutrino (QDN) masses are stud-ied with neutrino mass matrices obeying {\\mu} - {\\tau} symmetry for normal as well as inverted hierarchical mass patterns. We have made further investigations on 1) the prediction of solar mixing angle which lies below tri-bimaximal mixing value in consistent with neutrino oscillation observational data, 2) the prediction on absolute neutrino mass parameter (mee) in 0{\

  13. Solar Neutrinos

    Science.gov (United States)

    Davis, R. Jr.; Harmer, D. S.

    1964-12-01

    The prospect of studying the solar energy generation process directly by observing the solar neutrino radiation has been discussed for many years. The main difficulty with this approach is that the sun emits predominantly low energy neutrinos, and detectors for observing low fluxes of low energy neutrinos have not been developed. However, experimental techniques have been developed for observing neutrinos, and one can foresee that in the near future these techniques will be improved sufficiently in sensitivity to observe solar neutrinos. At the present several experiments are being designed and hopefully will be operating in the next year or so. We will discuss an experiment based upon a neutrino capture reaction that is the inverse of the electron-capture radioactive decay of argon-37. The method depends upon exposing a large volume of a chlorine compound, removing the radioactive argon-37 and observing the characteristic decay in a small low-level counter.

  14. The Jiangmen Underground Neutrino Observatory

    CERN Document Server

    Grassi, Marco

    2016-01-01

    The Jiangmen Underground Neutrino Observatory (JUNO) is a large and high precision liquid scintillator detector under construction in the south of China. With its 20 kt target mass, it aims to achieve an unprecedented 3% energy resolution at 1 MeV. Its main goal is to study the disappearance of reactor antineutrino to determine the neutrino mass ordering, and to precisely measure the mixing parameters $\\theta_{12}$, $\\Delta m^2_{12}$, and $\\Delta m ^2_{ee}$. It also aims to detect neutrinos emitted from radioactive processes taking place within the inner layers of the Earth (geonutrinos), as well as neutrinos produced during rare supernova bursts. Neutrinos emitted in solar nuclear reactions could also be observed, if stringent radiopurity requirements on the scintillator are met. This manuscript provides some highlights of JUNO's Physics Programme, and describes the detector design, as well as the ongoing detector R&D.

  15. Lepton physics versus neutrino mass

    International Nuclear Information System (INIS)

    The relationship between the strength of lepton flavour violating processes and the magnitude of the neutrino mass is rather model dependent. I review this question within different neutrino mixing models including superstring inspired models. Processes such as μ→e+γ, μ→3e, μ-e conversion in nuclei, etc. as well as lepton flavour violating Z0 decays can occur even if the physical neutrinos are strictly massless. As a result, the corresponding rates are unconstrained by bounds on the neutrino mass that follow from laboratory, astrophysics and cosmology and can therefore be large. Leptonic CP violation may also occur even when the physical neutrinos are strictly massless. (orig.)

  16. 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.

  17. Tritium neutrino mass experiments

    International Nuclear Information System (INIS)

    The current status of the experimental search for neutrino mass is reviewed, with emphasis on direct kinematic methods, such as the beta decay of tritium. The situation concerning the electron neutrino mass as measured in tritium beta decay is essentially unchanged from a year ago, although a great deal of experimental work is in progress. The ITEP group continues to find evidence for a nonzero mass, now slightly revised to 26(5) eV. After correcting for recently discovered errors in the energy loss distribution and source thickness, however, the Z/umlt u/rich group still claims and upper limit of 18 eV. There may be evidence for neutrino mass and mixing in the SN1987a data, in the same range suggested by the ITEP experiment. 42 refs., 3 figs

  18. Neutrinos Confronting Large Extra Dimensions

    CERN Document Server

    Maalampi, J; Vilja, I

    2001-01-01

    We study neutrino physics in a model with one large extra dimension. We assume the existence of two four-dimensional branes in the five-dimensional space-time, one for the ordinary particles and the other one for mirror particles, and we investigate neutrino masses and mixings in this scheme. Comparison of experimental neutrino data with the predictions of the model leads to various restrictions on the parameters of the model. For instance, the size of the extra dimension, R, turns out to be bounded from below. Cosmological considerations seem to favor a large R. The usual mixing schemes proposed as solutions to the solar and atmospheric neutrino anomalies are compatible with our model.

  19. Atmospheric neutrinos, nu_e-nu_s oscillations, and a novel neutrino evolution equation

    CERN Document Server

    Akhmedov, Evgeny

    2016-01-01

    If a sterile neutrino nu_s with an eV-scale mass and a sizeable mixing to the electron neutrino exists, as indicated by the reactor and gallium neutrino anomalies, a strong resonance enhancement of nu_e-nu_s oscillations of atmospheric neutrinos should occur in the TeV energy range. At these energies neutrino flavour transitions in the 3+1 scheme depend on just one neutrino mass squared difference and are fully described within a 3-flavour oscillation framework. We demonstrate that the flavour transitions of atmospheric nu_e can actually be very accurately described in a 2-flavour framework, with neutrino flavour evolution governed by an inhomogeneous Schroedinger-like equation. Evolution equations of this type have not been previously considered in the theory of neutrino oscillations.

  20. A Sterile Neutrino at DUNE

    CERN Document Server

    Berryman, Jeffrey M; Kelly, Kevin J; Kobach, Andrew

    2015-01-01

    We investigate the potential for the Deep Underground Neutrino Experiment (DUNE) to probe the existence and effects of a fourth neutrino mass-eigenstate. We study the mixing of the fourth mass-eigenstate with the three active neutrinos of the Standard Model, including the effects of new sources of CP-invariance violation, for a wide range of new mass-squared differences, from lower than 10^-5 eV^2 to higher than 1 eV^2. DUNE is sensitive to previously unexplored regions of the mixing angle - mass-squared difference parameter space. If there is a fourth neutrino, in some regions of the parameter space, DUNE is able to measure the new oscillation parameters (some very precisely) and clearly identify two independent sources of CP-invariance violation. Finally, we use the hypothesis that there are four neutrino mass-eigenstates in order to ascertain how well DUNE can test the limits of the three-massive-neutrinos paradigm. In this way, we briefly explore whether light sterile neutrinos can serve as proxies for ot...

  1. Light sterile neutrinos, lepton number violating interactions and short baseline neutrino experiments

    Science.gov (United States)

    Babu, K. S.; McKay, D. W.; Mocioiu, Irina; Pakvasa, Sandip

    2016-06-01

    We develop the consequences of introducing a purely leptonic, non-standard interaction (NSI) ΔL = 2, four-fermion effective Lagrangian and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short-baseline, neutrino experiments. We focus on the muon decay at rest (DAR) results from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford medium Energy Neutrino Experiment (KARMEN), seeking a reconciliation between the two. Both v¯e appearance from v¯μ oscillation and v¯e survival after production from NSI decay of the µ+ contribute to the expected signal. This is a unique feature of our scheme. We comment on further implications of the lepton number violating interaction and sterile neutrino-standard neutrino mixing.

  2. Quantum decoherence effect and neutrino oscillation

    CERN Document Server

    Sun, C P

    1998-01-01

    In the view of the quantum dynamic theory of measurement developed from the Hepp-Colemen (HC) model (K. Hepp, Hev.Phys.Acta, {\\bf 45}, 237 (1972)), the quantum decoherence in neutrino flavor oscillation caused by an environment surrounding neutrinos is generally considered in this paper. The Ellis, Hagelin, Nanopoulos and Srednicki (EHNS) mechanism for solving the solar neutrino problem can be comprehended in a framework of the ordinary quantum mechanics. In the weak- coupling limit, a microscopic model is proposed to describe the transition of two neutrino system from a pure state to a mixed state. It gives the modified formula of survival probability of neutrino oscillation with two additional time-dependent parameters. For specified environments, this result shows that the oscillating phenomena of neutrino still exist even without a mass difference in free neutrino.

  3. Multipartite entanglement in neutrino oscillations

    International Nuclear Information System (INIS)

    Particle mixing is related to multi-mode entanglement of single-particle states The occupation number of both flavor eigenstates and mass eigenstates can be used to define a multiqubit space. In such a framework, flavor neutrino states can be interpreted as multipartite mode-entangled states. By using two different entanglement measures, we analyze the behavior of multipartite entanglement in the phenomenon of neutrino oscillations.

  4. Axions, majorons and neutrino masses

    International Nuclear Information System (INIS)

    We point out that there is an intimate connection between the seesaw scale for the light neutrinos and the invisible axion scale based on a series of recent investigations on the neutrino masses and mixings within a class of realistic SO(10) models. We can then extend the standard model accordingly so that both the standard invisible axion and majoron can be treated in a naturally unified manner. 7 refs

  5. Multipartite entanglement in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, Massimo; Dell' Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio, E-mail: blasone@sa.infn.i [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy)

    2009-06-01

    Particle mixing is related to multi-mode entanglement of single-particle states The occupation number of both flavor eigenstates and mass eigenstates can be used to define a multiqubit space. In such a framework, flavor neutrino states can be interpreted as multipartite mode-entangled states. By using two different entanglement measures, we analyze the behavior of multipartite entanglement in the phenomenon of neutrino oscillations.

  6. Neutrinos in cosmology

    OpenAIRE

    Dolgov, A.D.(Novosibirsk State University, Novosibirsk, 630090, Russia)

    2002-01-01

    Cosmological implications of neutrinos are reviewed. The following subjects are discussed at a different level of scrutiny: cosmological limits on neutrino mass, neutrinos and primordial nucleosynthesis, cosmological constraints on unstable neutrinos, lepton asymmetry of the universe, impact of neutrinos on cosmic microwave radiation, neutrinos and the large scale structure of the universe, neutrino oscillations in the early universe, baryo/lepto-genesis and neutrinos, neutrinos and high ener...

  7. Neutrino magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Fernando; Pascoal, Kellen Alves [Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Mendonça, José Tito [IPFN, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal and Instituto de Física, Universidade de São Paulo, 05508-090 São Paulo, SP (Brazil)

    2016-01-15

    A new neutrino magnetohydrodynamics (NMHD) model is formulated, where the effects of the charged weak current on the electron-ion magnetohydrodynamic fluid are taken into account. The model incorporates in a systematic way the role of the Fermi neutrino weak force in magnetized plasmas. A fast neutrino-driven short wavelengths instability associated with the magnetosonic wave is derived. Such an instability should play a central role in strongly magnetized plasma as occurs in supernovae, where dense neutrino beams also exist. In addition, in the case of nonlinear or high frequency waves, the neutrino coupling is shown to be responsible for breaking the frozen-in magnetic field lines condition even in infinite conductivity plasmas. Simplified and ideal NMHD assumptions were adopted and analyzed in detail.

  8. Neutrino magnetohydrodynamics

    International Nuclear Information System (INIS)

    A new neutrino magnetohydrodynamics (NMHD) model is formulated, where the effects of the charged weak current on the electron-ion magnetohydrodynamic fluid are taken into account. The model incorporates in a systematic way the role of the Fermi neutrino weak force in magnetized plasmas. A fast neutrino-driven short wavelengths instability associated with the magnetosonic wave is derived. Such an instability should play a central role in strongly magnetized plasma as occurs in supernovae, where dense neutrino beams also exist. In addition, in the case of nonlinear or high frequency waves, the neutrino coupling is shown to be responsible for breaking the frozen-in magnetic field lines condition even in infinite conductivity plasmas. Simplified and ideal NMHD assumptions were adopted and analyzed in detail

  9. Neutrino Oscillations

    Directory of Open Access Journals (Sweden)

    G. Bellini

    2014-01-01

    Full Text Available In the last decades, a very important breakthrough has been brought about in the elementary particle physics by the discovery of the phenomenon of the neutrino oscillations, which has shown neutrino properties beyond the Standard Model. But a full understanding of the various aspects of the neutrino oscillations is far to be achieved. In this paper the theoretical background of the neutrino oscillation phenomenon is described, referring in particular to the paradigmatic models. Then the various techniques and detectors which studied neutrinos from different sources are discussed, starting from the pioneering ones up to the detectors still in operation and to those in preparation. The physics results are finally presented adopting the same research path which has been crossed by this long saga. The problems not yet fixed in this field are discussed, together with the perspectives of their solutions in the near future.

  10. Viability of $\\Delta m^2\\sim$ 1 eV$^2$ sterile neutrino mixing models in light of MiniBooNE electron neutrino and antineutrino data from the Booster and NuMI beamlines

    CERN Document Server

    Karagiorgi, G; Conrad, J; Shaevitz, M H; Sorel, M

    2009-01-01

    This paper examines sterile neutrino oscillation models in light of recently published results from the MiniBooNE Experiment. The new MiniBooNE data include the updated neutrino results, including the low energy region, and the first antineutrino results, as well as first results from the off-axis NuMI beam observed in the MiniBooNE detector. These new global fits also include data from LSND, KARMEN, NOMAD, Bugey, CHOOZ, CCFR84, and CDHS. Constraints from atmospheric oscillation data have been imposed.

  11. Highlights on experimental neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Ernesto [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2013-07-01

    Full text: In the last years a remarkable progress was achieved in a deeper understanding of neutrino sector. Nowadays we know all mixing angles and mass splits which govern the neutrino oscillation phenomena. The parameters of neutrino mixing were measured by combining results of different experimental approaches including accelerator beams, nuclear reactors, radiative decays and astrophysical neutrinos. Nevertheless, there are open questions which can be viewed as key points to consolidate our knowledge on the intrinsic properties of neutrinos such as mass hierarchy and the existence of a CP violation in leptonic sector. To answer these questions and also to improve the precision of the already known mixing parameters, a series of huge experimental efforts are being set up, even in a world-wide scale in some cases. In this presentation I will review the current knowledge of the fundamental properties of neutrinos and the experimental scenario in which we expect, in a time frame of a decade, to find missing pieces in the leptonic sector. The findings can strengthen the foundations of the Standard Model as well as open very interesting paths for new physics. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Justin; /University Coll. London; Whitehead, Lisa; /Brookhaven

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, Lisa [Brookhaven National Laboratory, Building 510E, P.O. Box 5000, Upton, NY 11973-5000 (United States); Evans, Justin [Physics building, University College London, Gower Street, London - WC1E 6BT (United Kingdom)

    2010-07-01

    MINOS is a long-baseline neutrino oscillation experiment situated along Fermilab's high-intensity NuMI neutrino beam. MINOS has completed an updated search for muon neutrino to electron neutrino transitions, observation of which would indicate a nonzero value for the neutrino mixing angle {theta}{sub 13}. The present 7x10{sup 20} protons-on-target data set represents more than double the exposure used in the previous analysis. The new result and its implications are presented. (author)

  14. 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.

  15. Split neutrinos - leptogenesis, dark matter and inflation

    OpenAIRE

    Mazumdar, Anupam; Morisi, Stefano

    2012-01-01

    We propose a simple framework to split neutrinos with a slight departure from tribimaximal mixing - where two of the neutrinos are Majorana type which provide thermal leptogenesis. The Dirac neutrino with a tiny Yukawa coupling explains primordial inflation and the cosmic microwave background radiation, where the inflaton is the gauge invariant flat direction. The observed baryon asymmetry, and the scale of inflation are intimately tied to the observed reactor angle, which can be further cons...

  16. The Daya Bay Reactor Neutrino Experiment

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    On Aug.15, 201l, a new large-scale scientific facility in China, Daya Bay Reactor Neutrino Experiment, started to operate. It is located in Daya Bay Nuclear Power Plant in Guangdong Province, around 50kin to both Hong Kong and Shenzhen City. The main scientific goal is to precisely determine the neutrino mixing angle 013 by detecting neutrinos from the reactors at different distances.

  17. Academic Training: Neutrino Physics, Present and Future

    CERN Multimedia

    2006-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 27, 28, 29, 30 November, 1st December, from 11:00 to 12:00 - TH Auditorium, bldg 4 - 3 - 006 Neutrino Physics, Present and Future B. KAYSER / Fermilab, USA Our understanding of neutrinos has been revolutionized by the discovery that they have nonzero masses and very large mixing. We will explain the phenomenology of massive neutrinos, including neutrino oscillation in vacuum and in matter, and the physics of neutrinos that are their own antiparticles. We will review the evidence for neutrino masses and mixing, and summarize what has been learned about the neutrinos so far. Identifying the very interesting open questions raised by the discovery of neutrino mass, we will discuss how these questions may be answered through future experiments. Finally, we will consider the possibility that CP violation by neutrinos is the key to understanding the matter-antimatter asymmetry of the universe, and discuss the see-saw theory of why neutrino masses are so tiny....

  18. Academic Training: Neutrino Physics, Present and Future

    CERN Multimedia

    2006-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 27, 28, 29, 30 November, 1st December, from 11:00 to 12:00 - TH Auditorium, bldg 4 - 3 - 006 Neutrino Physics, Present and Future B. KAYSER, Fermilab, USA Our understanding of neutrinos has been revolutionized by the discovery that they have nonzero masses and very large mixing. We will explain the phenomenology of massive neutrinos, including neutrino oscillation in vacuum and in matter, and the physics of neutrinos that are their own antiparticles. We will review the evidence for neutrino masses and mixing, and summarize what has been learned about the neutrinos so far. Identifying the very interesting open questions raised by the discovery of neutrino mass, we will discuss how these questions may be answered through future experiments. Finally, we will consider the possibility that CP violation by neutrinos is the key to understanding the matter-antimatter asymmetry of the universe, and discuss the see-saw theory of why neutrino masses are so tiny....

  19. Entanglement in neutrino oscillations

    OpenAIRE

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

    2007-01-01

    Flavor oscillations in elementary particle physics are related to multi-mode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We disc...

  20. Neutrinos and flavor symmetries

    Science.gov (United States)

    Tanimoto, Morimitsu

    2015-07-01

    We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ13 and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ13 is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.

  1. Neutrinos and flavor symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Tanimoto, Morimitsu

    2015-07-15

    We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ{sub 13} and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ{sub 13} is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.

  2. An overview of the Daya Bay Reactor Neutrino Experiment

    CERN Document Server

    Cao, Jun

    2016-01-01

    The Daya Bay Reactor Neutrino Experiment discovered an unexpectedly large neutrino oscillation related to the mixing angle $\\theta_{13}$ in 2012. This finding paved the way to the next generation of neutrino oscillation experiments. In this article, we review the history, featured design, and scientific results of Daya Bay. Prospects of the experiment are also described.

  3. An overview of the Daya Bay reactor neutrino experiment

    Science.gov (United States)

    Cao, Jun; Luk, Kam-Biu

    2016-07-01

    The Daya Bay Reactor Neutrino Experiment discovered an unexpectedly large neutrino oscillation related to the mixing angle θ13 in 2012. This finding paved the way to the next generation of neutrino oscillation experiments. In this article, we review the history, featured design, and scientific results of Daya Bay. Prospects of the experiment are also described.

  4. Neutrino properties from observations of SN 1987A

    International Nuclear Information System (INIS)

    Observations of the neutrino burst from SN 1987A by KAMIOKANDE II and IMB water Cherenkov detectors are discussed. They yield strong constraints on the lifetime, mass, mixings, electric charge and magnetic moment of the electron neutrino and on the number of flavors of light neutrinos

  5. Light sterile neutrino production in the early universe with dynamical neutrino asymmetries

    CERN Document Server

    Mirizzi, Alessandro; Miele, Gennaro; Serpico, Pasquale Dario

    2012-01-01

    Light sterile neutrinos mixing with the active ones have been recently proposed to solve different anomalies observed in short-baseline oscillation experiments. These neutrinos can also be produced by oscillations of the active neutrinos in the early universe, leaving possible traces on different cosmological observables. Here we perform an updated study of the neutrino kinetic equations in (3+1) and (2+1) oscillation schemes, dynamically evolving primordial asymmetries of active neutrinos and taking into account for the first time CP-violation effects. In the absence of neutrino asymmetries, eV-mass scale sterile neutrinos would be completely thermalized creating a tension with respect to the CMB, LSS and BBN data. In the past literature, active neutrino asymmetries have been invoked as a way to inhibit the sterile neutrino production via the in-medium suppression of the sterile-active mixing angle. However, neutrino asymmetries also permit a resonant sterile neutrino production. We find that if the active s...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Updating neutrino magnetic moment constraints

    Directory of Open Access Journals (Sweden)

    B.C. Cañas

    2016-02-01

    Full Text Available In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs, discussing both the constraints on the magnitudes of the three transition moments Λi and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1×10−11μB at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Λ1|≤5.6×10−11μB, |Λ2|≤4.0×10−11μB, and |Λ3|≤3.1×10−11μB (90% C.L., irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.

  11. Possible explanation of the solar-neutrino puzzle

    Science.gov (United States)

    Bethe, H. A.

    1986-01-01

    A new derivation of the Mikheyev and Smirnov (1985) mechanism for the conversion of electron neutrinos into mu neutrinos when traversing the sun is presented, and various hypotheses set forth. It is assumed that this process is responsible for the detection of fewer solar neutrinos than expected, with neutrinos below a minimum energy, E(m), being undetectable. E(m) is found to be about 6 MeV, and the difference of the squares of the respective neutrino masses is calculated to be 6 X 10 to the - 5th sq eV. A restriction on the neutrino mixing angle is assumed such that the change of density near the crossing point is adiabatic. It is predicted that no resonance conversion of neutrinos will occur in the dense core of supernovae, but conversion of electron neutrinos to mu neutrinos will occur as they escape outward through a density region around 100.

  12. Precision measurement of neutrino oscillation parameters at INO-ICAL detector

    Indian Academy of Sciences (India)

    Daljeet Kaur; Md Naimuddin; Sanjeev Kumar Verma

    2016-02-01

    A magnetized Iron CALorimeter (ICAL) detector at the India-based neutrino observatory (INO) is used to study neutrino oscillation sensitivity using atmospheric muon neutrino source. The ICAL detector will be able to detect muon tracks and hadron showers produced by neutrino interactions with the iron target. We have performed precision measurement analysis for the atmospheric neutrino oscillation parameters with the muon neutrino events, generated by Monte Carlo NUANCE event generator. A marginalized 2 analysis based on reconstructed neutrino energy and muon zenith angle binning scheme has been performed to determine the sensitivity for the atmospheric neutrino mixing parameters, ${\\rm sin}^{2} \\theta_{23}$ and $|\\Delta m^{2}_{23}|$.

  13. Tau contribution and precision measurement of theta23 at a neutrino factory

    CERN Document Server

    Indumathi, D

    2009-01-01

    We discuss precision measurements of the leading atmospheric parameters at a standard neutrino factory. The oscillation of the muon and electron neutrinos (anti-neutrinos) to tau neutrinos (anti-neutrinos) adds to the muon events sample (both right sign and wrong sign) via leptonic decays of the taus produced through charge-current interactions in the detector. We focus on how this contribution affects a precision measurement of the atmospheric mixing parameters and the deviation of muon neutrino -- tau neutrino mixing from maximality.

  14. Sterile neutrinos

    Science.gov (United States)

    Kopp, J.; Machado, P. A. N.; Maltoni, M.; Schwetz, T.

    2016-06-01

    We characterize statistically the indications of a presence of one or more light sterile neutrinos from MiniBooNE and LSND data, together with the reactor and gallium anomalies, in the global context. The compatibility of the aforementioned signals with null results from solar, atmospheric, reactor, and accelerator experiments is evaluated. We conclude that a severe tension is present in the global fit, and therefore the addition of eV-scale sterile neutrinos does not satisfactorily explain the anomalies.

  15. Search for Sterile Neutrinos at OPERA and other Long--Baseline Experiments

    CERN Document Server

    Stanco, Luca

    2015-01-01

    The OPERA experiment at the CNGS beam has observed muon to tau neutrino oscillations in the atmospheric sector. Based on this result new limits on the mixing parameters of a massive sterile neutrino may be set. Preliminary results of the analysis done in the 3+1 neutrino framework are here presented. An update of the search for sterile neutrinos in the $\

  16. Neutrino Oscillations as a Probe of Light Scalar Dark Matter

    OpenAIRE

    Berlin, Asher

    2016-01-01

    We consider a class of models involving interactions between ultra-light scalar dark matter and Standard Model neutrinos. Such couplings modify the neutrino mass splittings and mixing angles to include additional components that vary in time periodically with a frequency and amplitude set by the mass and energy density of the dark matter. Null results from recent searches for anomalous periodicities in the solar neutrino flux strongly constrain the dark matter-neutrino coupling to be orders o...

  17. Neutrino oscillations: Present status and outlook

    Indian Academy of Sciences (India)

    Thomas Schwetz

    2009-01-01

    The status of neutrino oscillations from global data is summarized, with the focus on the three-flavour picture. The status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of recent MiniBooNE results is also discussed. Further-more, an outlook on the measurement of the mixing angle 13 in the near term future, as well as prospects to discover CP violation in neutrino oscillations and to determine the type of the neutrino mass ordering by long-baseline experiments in the long term future are given.

  18. Neutrino Interactions and Long-Baseline Experiments

    CERN Document Server

    Mosel, Ulrich

    2016-01-01

    The extraction of neutrino mixing parameters and the CP-violating phase requires knowledge of the neutrino energy. This energy must be reconstructed from the final state of a neutrino-nucleus reaction since all long-baseline experiments use nuclear targets. This reconstruction requires detailed knowledge of the neutrino reactions with bound nucleons and of the final state interactions of hadrons with the nuclear environment. Quantum-kinetic transport theory can be used to build an event generator for this reconstruction that takes basic nuclear properties, such as binding, into account. Some examples are discussed that show the effects of nuclear interactions on observables in long-baseline experiments

  19. Sterile Neutrinos in Cold Climates

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Benjamin J.P. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-09-01

    Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified, and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to sin224 ≤ 0.02 at m2 ~ 0.3 eV2, and the LSND and Mini

  20. Neutrino observables from predictive flavour patterns

    Energy Technology Data Exchange (ETDEWEB)

    Cebola, Luis M.; Emmanuel-Costa, David [Universidade de Lisboa, Departamento de Fisica and Centro de Fisica Teorica de Particulas - CFTP, Instituto Superior Tecnico, Lisboa (Portugal); Felipe, Ricardo Gonzalez [Universidade de Lisboa, Departamento de Fisica and Centro de Fisica Teorica de Particulas - CFTP, Instituto Superior Tecnico, Lisboa (Portugal); ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politecnico de Lisboa, Lisboa (Portugal)

    2016-03-15

    We look for predictive flavour patterns of the effective Majorana neutrino mass matrix that are compatible with current neutrino oscillation data. Our search is based on the assumption that the neutrino mass matrix contains equal elements and a minimal number of parameters, in the flavour basis where the charged lepton mass matrix is diagonal and real. Three unique patterns that can successfully explain neutrino observables at the 3σ confidence level with just three physical parameters are presented. Neutrino textures described by four and five parameters are also studied. The predictions for the lightest neutrino mass, the effective mass parameter in neutrinoless double beta decays and for the CP-violating phases in the leptonic mixing are given. (orig.)

  1. Measurements of Neutrino Oscillation Angle theta_13

    CERN Document Server

    Kuze, Masahiro

    2013-01-01

    Neutrinos exhibit an interesting phenomenon called 'neutrino oscillation', in which a neutrino changes its flavor after traveling some flight length. Many experiments measured the mixing angles and mass differences, but the angle $\\theta_{13}$ had been unmeasured due to its smallness compared to others. During 2011 and 2012, series of new-generation neutrino experiments reported positive results in $\\theta_{13}$ search, and its value has been determined to be just below the previous upper limit. The non-zero result of $\\theta_{13}$ is a very good news for future of neutrino physics, since it opens a possibility of measuring the CP violation phase in the lepton sector. An introduction to neutrino oscillation and latest experimental results are presented. A detail is put on Double Chooz reactor experiment, in which the author is involved.

  2. Neutrino observables from predictive flavour patterns

    CERN Document Server

    Cebola, Luis M; Felipe, Ricardo Gonzalez

    2016-01-01

    We look for predictive flavour patterns of the effective Majorana neutrino mass matrix that are compatible with current neutrino oscillation data. Our search is based on the assumption that the neutrino mass matrix contains equal elements and a minimal number of parameters, in the flavour basis where the charged lepton mass matrix is diagonal and real. Three unique patterns that can successfully explain neutrino observables at the $3\\sigma$ confidence level with just three physical parameters are presented. Neutrino textures described by four and five parameters are also studied. The predictions for the lightest neutrino mass, the effective mass parameter in neutrinoless double beta decays and the CP-violating phases in the leptonic mixing are given.

  3. Testing constrained sequential dominance models of neutrinos

    Science.gov (United States)

    Björkeroth, Fredrik; King, Stephen F.

    2015-12-01

    Constrained sequential dominance (CSD) is a natural framework for implementing the see-saw mechanism of neutrino masses which allows the mixing angles and phases to be accurately predicted in terms of relatively few input parameters. We analyze a class of CSD(n) models where, in the flavour basis, two right-handed neutrinos are dominantly responsible for the ‘atmospheric’ and ‘solar’ neutrino masses with Yukawa couplings to ({ν }e,{ν }μ ,{ν }τ ) proportional to (0,1,1) and (1,n,n-2), respectively, where n is a positive integer. These coupling patterns may arise in indirect family symmetry models based on A 4. With two right-handed neutrinos, using a χ 2 test, we find a good agreement with data for CSD(3) and CSD(4) where the entire Pontecorvo-Maki-Nakagawa-Sakata mixing matrix is controlled by a single phase η, which takes simple values, leading to accurate predictions for mixing angles and the magnitude of the oscillation phase | {δ }{CP}| . We carefully study the perturbing effect of a third ‘decoupled’ right-handed neutrino, leading to a bound on the lightest physical neutrino mass {m}1{{≲ }}1 meV for the viable cases, corresponding to a normal neutrino mass hierarchy. We also discuss a direct link between the oscillation phase {δ }{CP} and leptogenesis in CSD(n) due to the same see-saw phase η appearing in both the neutrino mass matrix and leptogenesis.

  4. Mixed

    Directory of Open Access Journals (Sweden)

    Pau Baya

    2011-05-01

    Full Text Available Remenat (Catalan (Mixed, "revoltillo" (Scrambled in Spanish, is a dish which, in Catalunya, consists of a beaten egg cooked with vegetables or other ingredients, normally prawns or asparagus. It is delicious. Scrambled refers to the action of mixing the beaten egg with other ingredients in a pan, normally using a wooden spoon Thought is frequently an amalgam of past ideas put through a spinner and rhythmically shaken around like a cocktail until a uniform and dense paste is made. This malleable product, rather like a cake mixture can be deformed pulling it out, rolling it around, adapting its shape to the commands of one’s hands or the tool which is being used on it. In the piece Mixed, the contortion of the wood seeks to reproduce the plasticity of this slow heavy movement. Each piece lays itself on the next piece consecutively like a tongue of incandescent lava slowly advancing but with unstoppable inertia.

  5. Future Neutrino Long Baseline Experiments

    International Nuclear Information System (INIS)

    A new generation of reactor and accelerator neutrino oscillation experiments - Double Chooz, Daya Bay, Reno, T2K and NOA - is ready to start a sensitive search for oscillation signals generated by the mixing parameter θ13. Their output will be a fundamental milestone to optimize further experiments aimed at detecting CP violation in the neutrino sector, a key phenomenon with profound implications in particle physics and cosmology. Since late 90s, a world-wide activity is in progress to design facilities that can access CP violation in neutrino oscillation and perform high precision measurements of the lepton mixing matrix. In this paper the status of these studies will be summarized, focusing on the options that are best suited to exploit existing European facilities. (author)

  6. A Model for Pseudo-Dirac Neutrinos: Leptogenesis and Ultra-High Energy Neutrinos

    CERN Document Server

    Ahn, Y H; Kim, C S

    2016-01-01

    We propose a model where sterile neutrinos are introduced to make light neutrinos to be pseudo-Dirac particles. It is shown how tiny mass splitting necessary for realizing pseudo-Dirac neutrinos can be achieved. Within the model, we show how leptogenesis can be successfully generated. Motivated by the recent observation of very high energy neutrino events at IceCube, we study a possibility to observe the effects of the pseudo-Dirac property of neutrinos by performing astronomical-scale baseline experiments to uncover the oscillation effects of very tiny mass splitting. Using the result of global fit to neutrino data for the input of neutrino mixing angles and CP phase at $1\\sigma$ C.L. and fixing neutrino energy and mass splittings, we study how the oscillation effects induced by pseudo-Dirac neutrinos may affect the track-to-shower ratio obtained from IceCube data. We also discuss future prospect to observe the effects of the pseudo-Dirac property of neutrinos at high energy neutrino experiments.

  7. Probing CP violation in neutrino oscillations with neutrino telescopes

    CERN Document Server

    Blum, Kfir; Waxman, Eli

    2007-01-01

    Measurements of flavor ratios of astrophysical neutrino fluxes are sensitive to the two yet unknown mixing parameters $\\theta_{13}$ and $\\delta$ through the combination $\\sin\\theta_{13}\\cos\\delta$. We extend previous studies by considering the possibility that neutrino fluxes from more than a single type of sources will be measured. We point out that, if reactor experiments establish a lower bound on $\\theta_{13}$, then neutrino telescopes might establish an upper bound on $|\\cos\\delta|$ that is smaller than one, and by that prove that CP is violated in neutrino oscillations. Such a measurement requires several favorable ingredients to occur: (i) $\\theta_{13}$ is not far below the present upper bound; (ii) The uncertainties in $\\theta_{12}$ and $\\theta_{23}$ are reduced by a factor of about two; (iii) Neutrino fluxes from muon-damped sources are identified, and their flavor ratios measured with accuracy of order 10% or better. For the last condition to be achieved with the planned km^3 detectors, the neutrino...

  8. Neutrino factory near detector

    OpenAIRE

    Bogomilov, M.; Y. Karadzhov; Matev, R.; Tsenov, R.; Laing, A.; F.J.P. Soler

    2013-01-01

    The neutrino factory is a facility for future precision studies of neutrino oscillations. A so-called near detector is essential for reaching the required precision for a neutrino oscillation analysis. The main task of the near detector is to measure the flux of the neutrino beam. Such a high intensity neutrino source like a neutrino factory provides also the opportunity for precision studies of various neutrino interaction processes in the near detector. We discuss the design concepts of suc...

  9. Neutrino Catalyzed Diphoton Excess

    CERN Document Server

    Chao, Wei

    2015-01-01

    In this paper we explain the 750 GeV diphoton resonance observed at the run-2 LHC as a scalar singlet $S$, that plays a key rule in generating tiny but nonzero Majorana neutrino masses. The model contains four electroweak singlets: two leptoquarks, a singly charged scalar and a neutral scalar $S$. Majorana neutrino masses might be generated at the two-loop level as $S$ get nonzero vacuum expectation value. $S$ can be produced at the LHC through the gluon fusion and decays into diphoton at the one-loop level with charged scalars running in the loop. The model fits perfectly with a wide width of the resonance. Constraints on the model are investigated, which shows a negligible mixing between the resonance and the standard model Higgs boson.

  10. Solar neutrino oscillation phenomenology

    Indian Academy of Sciences (India)

    Srubabati Goswami

    2004-02-01

    This article summarises the status of the solar neutrino oscillation phenomenology at the end of 2002 in the light of the SNO and KamLAND results. We first present the allowed areas obtained from global solar analysis and demonstrate the preference of the solar data towards the large-mixing-angle (LMA) MSW solution. A clear confirmation in favour of the LMA solution comes from the KamLAND reactor neutrino data. the KamLAND spectral data in conjunction with the global solar data further narrows down the allowed LMA region and splits it into two allowed zones - a low $ m^{2}$ region (low-LMA) and high $ m^{2}$ region (high-LMA). We demonstrate through a projected analysis that with an exposure of 3 kton-year (kTy) KamLAND can remove this ambiguity.

  11. The three neutrino scenario

    International Nuclear Information System (INIS)

    I have discussed in my talk several remaining issues in the standard three-flavor mixing scheme of neutrinos, in particular, the sign of Δm213 and the leptonic CP violating phase. In this report I focus on two topics: (1) supernova method for determining the former sign, and (2) illuminating how one can detect the signatures for both of them in long-baseline (> or approx. 10 km) neutrino oscillation experiments. I do this by formulating perturbative frameworks appropriate for the two typical options of such experiments, the high energy and the low energy options with beam energies of ∼ 10 GeV and ∼ 100 MeV, respectively

  12. A global analysis of neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Fogli, G.L. [Dipartimento Interateneo di Fisica “Michelangelo Merlin”, Via Amendola 173, 70126 Bari (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Lisi, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Marrone, A. [Dipartimento Interateneo di Fisica “Michelangelo Merlin”, Via Amendola 173, 70126 Bari (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Montanino, D. [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Via Arnesano, 73100 Lecce (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, Via Arnesano, 73100 Lecce (Italy); Palazzo, A. [Cluster of Excellence, Origin and Structure of the Universe, Technische Universität München, Boltzmannstraße 2, D-85748 Garching (Germany); Rotunno, A.M. [Dipartimento Interateneo di Fisica “Michelangelo Merlin”, Via Amendola 173, 70126 Bari (Italy)

    2013-02-15

    We present a global analysis of neutrino oscillation data, including high-precision measurements of the neutrino mixing angle θ{sub 13} at reactor experiments, which have confirmed previous indications in favor of θ{sub 13}>0. Recent data presented at this Conference are also included. We focus on the correlations between θ{sub 13} and the mixing angle θ{sub 23}, as well as between θ{sub 13} and the neutrino CP-violation phase δ. We find interesting indications for θ{sub 23}<π/4 and possible hints for δ∼π, with no significant difference between normal and inverted mass hierarchy.

  13. Natural Dirac Neutrinos from Warped Extra Dimension

    CERN Document Server

    Wu, Jackson M S

    2010-01-01

    Dirac neutrinos arising from gauged discrete symmetry \\`a la Krauss-Wilczek are implemented in the minimal custodial Randall-Sundrum model. In the case of a normal hierarchy, all lepton masses and mixing pattern can be naturally reproduced at the TeV scale set by the electroweak constraints, while simultanously satisfy bounds from lepton flavour violation. A nonzero neutrino mixing angle, $\\theta_{13}$, is generic in the scenario, as well as the existence of sub-TeV right-handed Kaluza-Klein neutrinos, which may be searched for at the LHC.

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

    Science.gov (United States)

    Xing, Zhi-Zhong

    2009-04-01

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

  15. Observation of Electron Neutrino Appearance in a Muon Neutrino Beam

    CERN Document Server

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

    2013-01-01

    The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3$\\sigma$ when compared to 4.92 $\\pm$ 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles $\\theta_{12}$, $\\theta_{23}$, $\\theta_{13}$, a mass difference $\\Delta m^2_{32}$ and a CP violating phase $\\delta_{\\mathrm{CP}}$. In this neutrino oscillation scenario, assuming $|\\Delta m^2_{32}| = 2.4 \\times 10^{-3}$ $\\rm eV^2$, $\\sin^2 \\theta_{23} = 0.5$, $\\delta_{\\mathrm{CP}}=0$, and $\\Delta m^2_{32} >0$ ($\\Delta m^2_{32} <0$), a best-fit value of $\\sin^2 2 \\theta_{13}$ = $0.140^{+0.038}_{-0.032}$ ($0.170^{+0.045}_{-0.037}$) is obtained.

  16. Observation of electron neutrino appearance in a muon neutrino beam.

    Science.gov (United States)

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

    2014-02-14

    The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L. PMID:24580687

  17. Democratic Approach To Atmospheric And Solar Neutrino Oscillations

    CERN Document Server

    Shafi, Qaisar; Shafi, Qaisar; Tavartkiladze, Zurab

    2002-01-01

    Working with a U(1) flavor symmetry, we show how the hierarchical structure in the charged fermion sector and a democratic approach for neutrinos that yields large solar and atmospheric neutrino mixings can be simultaneously realized in the MSSM framework. However, in SU(5) due to the unified multiplets we encounter difficulties. Namely, democracy for the neutrinos leads to a wrong hierarchical pattern for charged fermion masses and mixings. We discuss how this is overcome in flipped SU(5).

  18. Implications of Fermionic Dark Matter on recent neutrino oscillation data

    OpenAIRE

    Singirala, Shivaramakrishna

    2016-01-01

    We investigate flavor phenomenology and dark matter in the context of scotogenic model. In this model, the neutrino masses are generated through radiative corrections at one-loop level. Considering the neutrino mixing matrix to be of tri-bimaximal form with additional perturbations to accommodate the recently observed non-zero value of reactor mixing angle $\\theta_{13}$, we obtain the relation between various neutrino oscillation parameters and the model parameters. Working in degenerate heav...

  19. Obtaining nonvanishing $\\theta_{13}$ with constrained neutrino Yukawa matrix and implications for flavor model buildings

    CERN Document Server

    Zhao, Ya

    2016-01-01

    Assuming a diagonal Majorana neutrino mass matrix, we investigate the neutrino Yukawa textures which lead to a non-zero reactor mixing angle $\\theta_{13}$. The neutrino effective coupling matrix $\\kappa^{eff}$ is pre-diagonalized by a constant mixing pattern $V_{\

  20. The Borexino Solar Neutrino Experiment And Its Scintillator Containment Vessel

    CERN Document Server

    Cadonati, L

    2001-01-01

    Thirty years ago, the first solar neutrino detector proved fusion reactions power the Sun. However, the total rate detected in this and all subsequent solar neutrino experiments is consistently two to three times lower than predicted by the Standard Solar Model. Current experiments seek to explain this “solar neutrino puzzle” through non-standard particle properties, like neutrino mass and flavor mixing, within the context of the MSW theory. The detection of the monoenergetic 7Be solar neutrino is the missing clue for the solution of the solar neutrino problem; this constitutes the main physics goal of Borexino, a real- time, high-statistics solar neutrino detector located under the Gran Sasso mountain, in Italy. In the first part of this thesis, I present a Monte Carlo study of the expected performance of Borexino, with simulations of the neutrino rate, the external y background and the α/β/γ activity in the scintillator. The Standard Solar Model predicts a so...

  1. Neutrino Data and Neutrino-Antineutrino Transition

    CERN Document Server

    Alexeyev, E N

    2005-01-01

    A problem, whether a neutrino-antineutrino transition could be responsible for the muon neutrino deficit found in underground experiments (Super-Kamiokande, MACRO, Soudan 2) and in the accelerator long-baseline K2K experiment, is discussed in this paper. The intention of the work is not consideration of concrete models for muon neutrino-antineutrino transition but a desire to attract an attention to another possibility of understanding the nature of the measured muon neutrino deficit in neutrino experiments.

  2. BEST sensitivity to O(1) eV sterile neutrino

    CERN Document Server

    Barinov, Vladislav; Gorbunov, Dmitry; Ibragimova, Tatiana

    2016-01-01

    Numerous anomalous results in neutrino oscillation experiments can be attributed to interference of ~1 eV sterile neutrino. The specially designed to fully explore the Gallium anomaly Baksan Experiment on Sterile Transitions (BEST) starts next year. We investigate the sensitivity of BEST in searches for sterile neutrino mixed with electron neutrino. Then, performing the combined analysis of all the Gallium experiments (SAGE, GALLEX, BEST) we find the regions in model parameter space (sterile neutrino mass and mixing angle), which will be excluded if BEST agrees with no sterile neutrino hypothesis. For the opposite case, if BEST observes the signal as it follows from the sterile neutrino explanation of the Gallium (SAGE and GALLEX) anomaly, we show how BEST will improve upon the present estimates of the model parameters.

  3. Phenomenology of neutrino oscillations at the neutrino factory

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jian

    2011-12-19

    We consider the prospects for a neutrino factory measuring mixing angles, the CP violating phase and mass-squared differences by detecting wrong-charge muons arising from the chain {mu}{sup +} {yields} {nu}{sub e} {yields} {nu}{sub {mu}} {yields} {mu}{sup -} and the right-charge muons coming from the chain {mu}{sup +} {yields} anti {nu}{sub {mu}} {yields} anti {nu}{sub {mu}} {yields} {mu}{sup -} (similar to {mu}{sup -} chains), where {nu}{sub e} {yields} {nu}{sub {mu}} and anti {nu}{sub {mu}} {yields} anti {nu}{sub {mu}} are neutrino oscillation channels through a long baseline. First, we study physics with near detectors and consider the treatment of systematic errors including cross section errors, flux errors, and background uncertainties. We illustrate for which measurements near detectors are required, discuss how many are needed, and what the role of the flux monitoring is. We demonstrate that near detectors are mandatory for the leading atmospheric parameter measurements if the neutrino factory has only one baseline, whereas systematic errors partially cancel if the neutrino factory complex includes the magic baseline. Second, we perform the baseline and energy optimization of the neutrino factory including the latest simulation results from the magnetized iron neutrino detector (MIND). We also consider the impact of {tau} decays, generated by appearance channels {nu}{sub {mu}} {yields} {nu}{sub {tau}} and {nu}{sub e} {yields} {nu}{sub {tau}}, on the discovery reaches of the mass orderings, the leptonic CP violation, and the non-zero {theta}{sub 13}, which we find to be negligible for the considered detector. Third, we make a comparison of a high energy neutrino factory to a low energy neutrino factory and find that they are just two versions of the same experiment optimized for different regions of the parameter space. In addition, we briefly comment on whether it is useful to build the bi-magic baseline at the low energy neutrino factory. Finally, the

  4. Muon neutrino disappearance at MINOS

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, R [Indiana Univ., Bloomington, IN (United States)

    2009-08-01

    A strong case has been made by several experiments that neutrinos oscillate, although important questions remain as to the mechanisms and precise values of the parameters. In the standard picture, two parameters describe the nature of how the neutrinos oscillate: the mass-squared difference between states and the mixing angle. The purpose of this thesis is to use data from the MINOS experiment to precisely measure the parameters associated with oscillations first observed in studies of atmospheric neutrinos. MINOS utilizes two similar detectors to observe the oscillatory nature of neutrinos. The Near Detector, located 1 km from the source, observes the unoscillated energy spectrum while the Far Detector, located 735 km away, is positioned to see the oscillation signal. Using the data in the Near Detector, a prediction of the expected neutrino spectrum at the Far Detector assuming no oscillations is made. By comparing this prediction with the MINOS data, the atmospheric mixing parameters are measured to be Δm322 = 2.45+0.12-0.12 x 10-3 eV2 and sin232) = 1.00-0.04+0.00 (> 0.90 at 90% confidence level).

  5. 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.

  6. A Combined View of Sterile-Neutrino Constraints from CMB and Neutrino Oscillation Measurements

    CERN Document Server

    Bridle, Sarah; Evans, Justin; Fernandez, Susana; Guzowski, Pawel; Soldner-Rembold, Stefan

    2016-01-01

    We perform a comparative analysis of constraints on sterile neutrinos from the Planck experiment and from current and future neutrino oscillation experiments (MINOS, IceCube, SBN). For the first time, we express the Planck constraints on $N_{\\rm eff}$ and $m_{\\rm eff}^{\\rm sterile}$ from the Cosmic Microwave Background in the parameter space used by oscillation experiments using both mass-squared differences and mixing angles. In a model with a single sterile neutrino species and using standard assumptions, we find that the Planck data and the oscillation experiments measuring muon-neutrino disappearance have similar sensitivity.

  7. Liouville equations for neutrino distribution matrices

    CERN Document Server

    Cardall, Christian Y

    2007-01-01

    The classical notion of a single-particle scalar distribution function or phase space density can be generalized to a matrix in order to accommodate superpositions of states of discrete quantum numbers, such as neutrino mass/flavor. Such a `neutrino distribution matrix' is thus an appropriate construct to describe a neutrino gas that may vary in space as well as time and in which flavor mixing competes with collisions. The Liouville equations obeyed by neutrino distribution matrices, including the spatial derivative and vacuum flavor mixing terms, can be explicitly but elegantly derived in two new ways: from a covariant version of the familiar simple model of flavor mixing, and from the Klein-Gordon equations satisfied by a quantum `density function' (mean value of paired quantum field operators). Associated with the latter derivation is a case study in how the joint position/momentum dependence of a classical gas (albeit with Fermi statistics) emerges from a formalism built on quantum fields.

  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. Very low-energy neutrino interactions

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2015-05-15

    Neutrino-nucleus reaction cross sections are now evaluated rather accurately by shell-model (SM) or SM+RPA calculations based on recent advances in nuclear structure studies. Due to these achievements, reliable constraints on super-nova neutrino temperatures as well as neutrino oscillation parameters become possible. Supernova neutrino tempeatures are constrained from abundances of elements obtained by using new ν-nucleus reaction cross sections. A possibility of constructing supernova neutrino spectrum from beta-beam measurements is pointed out. Neutrino mass hierarchy and mixing angle θ{sub 13} can be determined from abundance ratio of {sup 7}Li/{sup 11}B, which is sensitive to the MSW matter oscillation effects in supernova explosions. Inverted mass hierarchy is shown to be statistically more favored based on a recent analysis of presolar grains. Effects of neutrino-neutrino interactions are also shown to play important roles in r-process nucleosynthesis. Importance and possibilities of direct measurements of ν-induced cross sections on {sup 40}Ar and {sup 208}Pb are discussed for future supernova neutrino detections. Recent calculations of the cross sections for ν-{sup 40}Ar are presented. The need for new theoretical evaluations of the cross sections for ν-{sup 208}Pb is pointed out. Challenges to experiments on coherent elastic scattering are presented.

  10. Neutrino cave

    CERN Multimedia

    1977-01-01

    Here the end of the underground decay tunnel, its window and beam stopper. On the left one sees the end of the last quadrupole of the neutrino narrow-band beam, and the detectors measuring the beam profile. Further downstream one sees two Beam Current Transformers (BCT, see photo 7801005) measuring the beam intensity, and a Cerenkov counter.

  11. Neutrino horn

    CERN Multimedia

    1967-01-01

    View of the new neutrino horn installed in its blockhouse from the target end. Protons pass through the 2mm hole in the centre of the small fluorescent screen, hitting the target immediately behind it. The circular tubes carry pressurized cooling water.

  12. The sensitivity of the ICAL detector at India-based Neutrino Observatory to neutrino oscillation parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Daljeet; Naimuddin, Md.; Kumar, Sanjeev [University of Delhi, Department of Physics and Astrophysics, Delhi (India)

    2015-04-01

    The India-based Neutrino Observatory will host a 50 kt magnetized iron calorimeter (ICAL) detector that will be able to detect muon tracks and hadron showers produced by charged-current muon neutrino interactions in the detector. The ICAL experiment will be able to determine the precision of atmospheric neutrino mixing parameters and neutrino mass hierarchy using atmospheric muon neutrinos through the earth matter effect. In this paper, we report on the sensitivity for the atmospheric neutrino mixing parameters(sin{sup 2}θ{sub 23} and vertical stroke Δm{sub 32}{sup 2} vertical stroke) and octant sensitivity for the ICAL detector using the reconstructed neutrino energy and muon direction as observables. We apply realistic resolutions and efficiencies obtained by the ICAL collaboration with a GEANT4-based simulation to reconstruct neutrino energy and muon direction. Our study shows that using neutrino energy and muon direction as observables for a χ{sup 2} analysis, the ICAL detector can measure sin{sup 2}θ{sub 23} and vertical stroke Δm{sub 32}{sup 2} vertical stroke with 13% and 4% uncertainties at 1σ confidence level and can rule out the wrong octant of θ{sub 23} with 2σ confidence level for 10 years of exposure. (orig.)

  13. 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_\

  14. 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.

  15. Neutrino Physics: what we have learned so far and what

    Energy Technology Data Exchange (ETDEWEB)

    Nunokawa, Hiroshi [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2013-07-01

    Full text: In the last 15 years, after the discovery of neutrino oscillation by the Super-Kamiokande collaboration in 1998, an enormous progress has been made in neutrino physics. Thanks to the recent results from reactor experiments which finally measured the angle theta13 whose value was not known for a long time, we now know all the mixing angles in the standard three flavor scheme. Yet there are several unknowns and open questions about neutrinos. I will try to discuss what we have learned so far and what we would like to know more about neutrinos.we would like to know more about neutrinos.

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

    Science.gov (United States)

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

    2016-08-01

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

  17. New ambiguity in probing CP violation in neutrino oscillations

    CERN Document Server

    Miranda, O G; Valle, J W F

    2016-01-01

    If neutrinos get mass a la seesaw the mixing matrix describing neutrino oscillations can be effectively non-unitary. We show that in this case the neutrino appearance probabilities involve a new CP phase, phi, associated to non-unitarity. This leads to an ambiguity in extracting the "standard" three--neutrino phase delta_CP, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of delta_CP.

  18. Non-Unitarity, sterile neutrinos, and Non-Standard neutrino Interactions

    CERN Document Server

    Blennow, Mattias; Fernandez-Martinez, Enrique; Hernandez-Garcia, Josu; Lopez-Pavon, Jacobo

    2016-01-01

    The simplest Standard Model extension to explain neutrino masses involves the addition of right-handed neutrinos. At some level, this extension will impact neutrino oscillation searches. In this work we explore the differences and similarities between the case in which these neutrinos are kinematically accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify apparent inconsistencies in the present literature when using different parametrizations to describe these effects and recast both limits in the popular neutrino non-standard interaction (NSI) formal- ism. We find that, in the limit in which sterile oscillations are averaged out at the near detector, their effects at the far detector coincide with non-unitarity at leading order, even in presence of a matter potential. We also summarize the present bounds existing in both limits and compare them with the expected sensitivities of near-future facilities taking the DUNE proposal as a bench- mark. We conclude that non-unitarity effects ...

  19. The Neutrino Factory and Beta Beam Experiments and Development

    CERN Document Server

    Albright, C; Beacom, J; Berg, J S; Black, E; Blondel, A; Bogacz, S; Brice, S; Caspi, S; Chou, W; Cummings, M; Fernow, R; Finley, D; Gallardo, J; Geer, S; Gómez-Cadenas, J J; Goodman, M; Harris, D; Huber, P; Jansson, A; Johnstone, C; Kahn, S; Kaplan, D; Kirk, H; Kobilarcik, T; Lindner, Manfred; McDonald, K; Mena, O; Neuffer, David V; Palladino, V; Palmer, R; Paul, K; Rapidis, P; Solomey, Nickolas; Spampinato, P T; Summers, D; Torun, Y; Whisnant, K; Winter, W; Zisman, M S

    2004-01-01

    The long-term prospects for fully exploring three-flavor mixing in the neutrino sector depend upon an ongoing and increased investment in the appropriate accelerator R\\&D. Two new concepts have been proposed that would revolutionize neutrino experiments, namely the Neutrino Factory and the Beta Beam facility. These new facilities would dramatically improve our ability to test the three-flavor mixing framework, measure \\textsl{CP} violation in the lepton sector, and perhaps determine the neutrino mass hierarchy, and, if necessary, probe extremely small values of the mixing angle $\\theta_{13}$. The stunning sensitivity that could be achieved with a Neutrino Factory is described, together with our present understanding of the corresponding sensitivity that might be achieved with a Beta Beam facility. In the Beta Beam case, additional study is required to better understand the optimum Beta Beam energy, and the achievable sensitivity. Neither a Neutrino Factory nor a Beta Beam facility could be built without s...

  20. Neutrino GDR meeting; Reunion du GDR neutrino

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Saavedra, J.A.; Camilleri, L.; Mention, G.; VanElewyck, V.; Verderi, M.; Blondel, A.; Augier, C.; Bellefon, A. de; Coc, A.; Duchesneau, D.; Favier, J.; Lesgourgues, J.; Payet, J

    2006-07-01

    The purpose of the neutrino GDR (research program coordination) is to federate the activities of French research teams devoted to studying the neutrino. The presentations have been organized on 2 days. A review of the present status of the theoretical and experimental knowledge on neutrinos on a worldwide basis has been made on the first day while the second day has been dedicated to reporting the activities of the 5 following working groups: 1) determination of neutrino parameters, 2) physics beyond the standard model, 3) neutrinos in the universe, 4) neutrino detection, and 5) common tools. During the first day the American neutrino research program has been presented through the description of the 2 neutrino detection systems: Nova and Minor. The following neutrino experiments involving nuclear reactors: Chooz (France), Daya-bay (China), Reno (Korea) and Angra (Brazil) have also been reviewed. This document is made up of the slides of the presentations.

  1. Muon Colliders and Neutrino Factories

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel M. [IIT, Chicago

    2015-05-29

    Muon colliders and neutrino factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies and precision measurements of Higgs boson and neutrino mixing matrix parameters. The facility performance and cost depend on how well a beam of muons can be cooled. Recent progress in muon cooling design studies and prototype tests nourishes the hope that such facilities could be built starting in the coming decade. The status of the key technologies and their various demonstration experiments is summarized. Prospects "post-P5" are also discussed.

  2. Neutrino beams and experiments

    International Nuclear Information System (INIS)

    After a brief review of the early history of neutrino experiments, the principle of neutrino beams at proton accelerators is described and a survey of neutrino experiments since 1963 is given. ((orig.))

  3. Expectation values of flavor-neutrino numbers with respect to neutrino-source hadron states: Neutrino oscillations and decay probabilities

    International Nuclear Information System (INIS)

    On the basis of quantum field theory, we consider a unified description of various processes accompanied by neutrinos, namely, weak decays and oscillation processes. The structures of the expectation values of flavor-neutrino numbers with respect to the neutrino-source hadron state are investigated. Due to the smallness of neutrino masses, we naturally obtain the old (i.e., pre-mixing) formulas of decay probabilities. In addition, it is shown that the oscillation formulas, similar to the usual ones, are derived irrespectively of the details of neutrino-producing processes. The derived oscillation formulas are regarded as being the same in form as the usually adopted ones, except for some simple distinctions

  4. Measuring neutrino mass without neutrinos!

    CERN Document Server

    Peach, Kenneth J

    2004-01-01

    Neutrinoless double beta decay offers the most precise (if challenging) way of measuring the absolute mass of the neutrino. Particle Physics met at the Rutherford Appleton Laboratory last autumn to discuss wether the UK should take a lead in setting up such an experiment

  5. Impact of sterile neutrino dark matter on core-collapse supernovae

    Science.gov (United States)

    Warren, Mackenzie L.; Mathews, Grant J.; Meixner, Matthew; Hidaka, Jun; Kajino, Toshitaka

    2016-09-01

    We summarize the impact of sterile neutrino dark matter on core-collapse supernova explosions. We explore various oscillations between electron neutrinos or mixed μ ‑ τ neutrinos and right-handed sterile neutrinos that may occur within a core-collapse supernova. In particular, we consider sterile neutrino masses and mixing angles that are consistent with sterile neutrino dark matter candidates as indicated by recent X-ray flux measurements. We find that the interpretation of the observed 3.5 keV X-ray excess as due to a decaying 7 keV sterile neutrino that comprises 100% of the dark matter would have almost no observable effect on supernova explosions. However, in the more realistic case in which the decaying sterile neutrino comprises only a small fraction of the total dark matter density due to the presence of other sterile neutrino flavors, WIMPs, etc. a larger mixing angle is allowed. In this case a 7 keV sterile neutrino could have a significant impact on core-collapse supernovae. We also consider mixing between μ ‑ τ neutrinos and sterile neutrinos. We find, however, that this mixing does not significantly alter the explosion and has no observable effect on the neutrino luminosities at early times.

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

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Stephen James [College of William and Mary, Williamsburg, VA (United States)

    2011-05-01

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

  7. Can a non-unitary effect be prominent In neutrino oscillation measurements?

    Institute of Scientific and Technical Information of China (English)

    L(U) Lei; WANG Wen-Yu; XIONG zhao-Hua

    2010-01-01

    Subject to neutrino experiments, the mixing matrix of ordinary neutrinos can still have small vi-olation from unitarity. We introduce a quasi-unitary matrix to interpret this violation and propose a natural scheme to parameterize it. A quasi-unitary factor △QF is defined to be measured in neutrino oscillation exper-iments and the numerical results show that the improvement in experimental precision may help us figure out the secret of neutrino mixing.

  8. Dirac neutrinos and SN 1987A

    Science.gov (United States)

    Turner, Michael S.

    1991-01-01

    Previous work has shown that the cooling of SN 1987A excludes a Dirac-neutrino mass greater than theta(20 keV) for nu(sub e), nu(sub mu), or nu(sub tau). The emission of wrong-helicity, Dirac neutrinos from SN 1987A, is re-examined. It is concluded that the effect of a Dirac neutrino on the cooling of SN 1987A has been underestimated due to neutrino degeneracy and additional emission processes. The limit that follows from the cooling of SN 1987A is believed to be greater (probably much greater) than 10 keV. This result is significant in light of the recent evidence for a 17 keV mass eigenstate that mixes with the electron neutrino.

  9. Investigation of Neutrino Properties with Bolometric Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Heeger, Karsten M [University of Wisconsin & Yale University

    2014-11-01

    Neutrino mass and mixing are amongst the major discoveries of the past decade. The particle nature of neutrinos and the hierarchy of mass eigenstates, however, are unknown. Neutrinoless double beta-decay (0νββ) is the only known mechanism to test whether neutrinos are their own antiparticles. The observation of 0νββ would imply lepton number violation and show that neutrinos have Majorana mass. This report describes research activities performed at the University of Wisconsin in 2011-2014 aimed at the search for 0νββ with CUORE-0 and CUORE with the goal of exploring the inverted mass hierarchy region and probing an effective neutrino mass of ~40- 120 meV.

  10. Neutrinos: Theory and Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Parke, Stephen

    2013-10-22

    The theory and phenomenology of neutrinos will be addressed, especially that relating to the observation of neutrino flavor transformations. The current status and implications for future experiments will be discussed with special emphasis on the experiments that will determine the neutrino mass ordering, the dominant flavor content of the neutrino mass eigenstate with the smallest electron neutrino content and the size of CP violation in the neutrino sector. Beyond the neutrino Standard Model, the evidence for and a possible definitive experiment to confirm or refute the existence of light sterile neutrinos will be briefly discussed.

  11. Neutrinos: Theory and Phenomenology

    CERN Document Server

    Parke, Stephen J

    2013-01-01

    The theory and phenomenology of neutrinos will be addressed, especially that relating to the observation of neutrino flavor transformations. The current status and implications for future experiments will be discussed with special emphasis on the experiments that will determine the neutrino mass ordering, the dominant flavor content of the neutrino mass eigenstate with the smallest electron neutrino content and the size of CP violation in the neutrino sector. Beyond the neutrino Standard Model, the evidence for and a possible definitive experiment to confirm or refute the existence of light sterile neutrinos will be briefly discussed.

  12. The Simplest Neutrino Mass Matrix

    CERN Document Server

    Harrison, P F

    2004-01-01

    We motivate the simplest ansatz for the neutrino mass matrix consistent with the data from neutrino oscillation experiments, and admitting CP violation. It has only two free parameters: an arbitrary mass-scale and a small dimensionless ratio. This mass matrix exhibits two symmetries, Democracy and Mutativity, which respectively ensure trimaximal mixing of the |nu_2> mass eigenstate, and mixing parameter values |theta_{23}|=45 degrees and |delta|=90 degrees, consistent with bimaximal mixing of the |nu_3> mass eigenstate. A third constraint relates the smallness of |U_{e3}|^2 to that of the mass-squared difference ratio, Delta m^2_sol/Delta m^2_atm, yielding the prediction sin(theta_{13})=sqrt{2 Delta m^2_sol/3 Delta m^2_atm} ~ 0.13 +- 0.03.

  13. Neutrinos in a Sterile Throat

    CERN Document Server

    Gripaios, Ben Matthew

    2007-01-01

    We consider field-theoretic models of a warped extra dimension with multiple throats, in which fermions that are singlets of the Standard Model gauge group propagate in a separate throat from the Standard Model fields, which we call the sterile throat. The singlets mix with Standard Model fields via interactions localized on the UV brane that connects the two throats. This leads to three, light, mostly-active, Majorana neutrinos via a higher-dimensional see-saw mechanism, together with Kaluza-Klein towers of mostly-sterile neutrinos, whose scale is set by the warp factor in the sterile throat and can be very low if the throat is deep. We suggest that a model of this kind may explain all the neutrino data, reconciling the LSND result with astrophysical constraints.

  14. The one loop corrections to the neutrino masses in BLMSSM

    Directory of Open Access Journals (Sweden)

    Shu-Min Zhao

    2016-09-01

    Full Text Available The neutrino masses and mixings are studied in the model which is the supersymmetric extension of the standard model with local gauged baryon and lepton numbers (BLMSSM. At tree level the neutrinos can obtain tiny masses through the See-Saw mechanism in the BLMSSM. The one-loop corrections to the neutrino masses and mixings are important, and they are studied in this work with the mass insertion approximation. We study the numerical results and discuss the allowed parameter space of BLMSSM. It can contribute to study the neutrino masses and to explore the new physics beyond the standard model (SM.

  15. The one loop corrections to the neutrino masses in BLMSSM

    Science.gov (United States)

    Zhao, Shu-Min; Feng, Tai-Fu; Dong, Xing-Xing; Zhang, Hai-Bin; Ning, Guo-Zhu; Guo, Tao

    2016-09-01

    The neutrino masses and mixings are studied in the model which is the supersymmetric extension of the standard model with local gauged baryon and lepton numbers (BLMSSM). At tree level the neutrinos can obtain tiny masses through the See-Saw mechanism in the BLMSSM. The one-loop corrections to the neutrino masses and mixings are important, and they are studied in this work with the mass insertion approximation. We study the numerical results and discuss the allowed parameter space of BLMSSM. It can contribute to study the neutrino masses and to explore the new physics beyond the standard model (SM).

  16. 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.

  17. Study on the Neutrino Oscillation with a Next Generation Medium-Baseline Reactor Experiment

    International Nuclear Information System (INIS)

    For over fifty years, reactor experiments have played an important role in neutrino physics, in both discoveries and precision measurements. One of the methods to verify the existence of neutrino is the observation of neutrino oscillation phenomena. Electron antineutrinos emitted from a reactor provide the measurement of the small mixing angle θ13, providing rich programs of neutrino properties, detector development, nuclear monitoring, and application. Using reactor neutrinos, future reactor neutrino experiments, more precise measurements of θ12,Δm122, and mass hierarchy will be explored. The precise measurement of θ13 would be crucial for measuring the CP violation parameters at accelerators. Therefore, reactor neutrino physics will assist in the complete understanding of the fundamental nature and implications of neutrino masses and mixing. In this paper, we investigated several characteristics of RENO-50, which is a future medium-baseline reactor neutrino oscillation experiment, by using the GloBES simulation package

  18. PREFACE: Neutrino physics at spallation neutron sources

    Science.gov (United States)

    Avignone, F. T.; Chatterjee, L.; Efremenko, Y. V.; Strayer, M.

    2003-11-01

    Unique because of their super-light masses and tiny interaction cross sections, neutrinos combine fundamental physics on the scale of the miniscule with macroscopic physics on the scale of the cosmos. Starting from the ignition of the primal p-p chain of stellar and solar fusion reactions that signal star-birth, these elementary leptons (neutrinos) are also critical players in the life-cycles and explosive deaths of massive stars and the production and disbursement of heavy elements. Stepping beyond their importance in solar, stellar and supernova astrophysics, neutrino interactions and properties influence the evolution, dynamics and symmetries of the cosmos as a whole. Further, they serve as valuable probes of its material content at various levels of structure from atoms and nuclei to valence and sea quarks. In the light of the multitude of physics phenomena that neutrinos influence, it is imperative to enhance our understanding of neutrino interactions and properties to the maximum. This is accentuated by the recent evidence of finite neutrino mass and flavour mixing between generations that reverberates on the plethora of physics that neutrinos influence. Laboratory experiments using intense neutrino fluxes would allow precision measurements and determination of important neutrino reaction rates. These can then complement atmospheric, solar and reactor experiments that have enriched so valuably our understanding of the neutrino and its repertoire of physics applications. In particular, intermediate energy neutrino experiments can provide critical information on stellar and solar astrophysical processes, along with advancing our knowledge of nuclear structure, sub-nuclear physics and fundamental symmetries. So where should we look for such intense neutrino sources? Spallation neutron facilities by their design are sources of intense neutrino pulses that are produced as a by-product of neutron spallation. These neutrino sources could serve as unique laboratories

  19. CP-phase effects on the effective neutrino mass $m_{ee}$ in the case of quasi-degenerate neutrinos

    OpenAIRE

    Maalampi, J.; Riittinen, J.

    2009-01-01

    We study the possibility that the three mass states of the ordinary active neutrinos actually split into pairs of quasi-degenerate states, with $\\Delta m^2_{kk'} \\sim 10^{-12}$ eV$^2$ or less, as a result of mixing of active neutrinos with sterile neutrinos. Although these quasi-degenerate pairs will look in laboratory experiment identical to single active states, the CP phase factors associated with active-sterile mixing might cause cancellations in the effective electron neutrino mass $m_{e...

  20. Turbulent Supernova Shock Waves and the Sterile Neutrino Signature in Megaton Water Detectors

    CERN Document Server

    Choubey, S; Ross, Graham G; Choubey, Sandhya

    2007-01-01

    The signatures of sterile neutrinos in the supernova neutrino signal in megaton water Cerenkov detectors are studied. Time dependent modulation of the neutrino signal emerging from the sharp changes in the oscillation probability due to shock waves is shown to be a smoking gun for the existence of sterile neutrinos. These modulations and indeed the entire neutrino oscillation signal is found to be different for the case with just three active neutrinos and the cases where there are additional sterile species mixed with the active neutrinos. The effect of turbulence is taken into account and it is found that the effect of the shock waves, while modifed, remain significant and measurable. Supernova neutrino signals in water detectors can therefore give unambiguous proof for the existence of sterile neutrinos, the sensitivity extending beyond that for terrestial neutrino experiments. In addition the time dependent modulations in the signal due to shock waves can be used to trace the evolution of the shock wave i...

  1. Neutrinoless double beta decay and heavy sterile neutrinos

    International Nuclear Information System (INIS)

    The experimental rate of neutrinoless double beta decay can be saturated by the exchange of virtual sterile neutrinos, that mix with the ordinary neutrinos and are heavier than 200 MeV. Interestingly, this hypothesis is subject only to marginal experimental constraints, because of the new nuclear matrix elements. This possibility is analyzed in the context of the Type I seesaw model, performing also exploratory investigations of the implications for heavy neutrino mass spectra, rare decays of mesons as well as neutrino-decay search, LHC, and lepton flavor violation. The heavy sterile neutrinos can saturate the rate only when their masses are below some 10 TeV, but in this case, the suppression of the light-neutrino masses has to be more than the ratio of the electroweak scale and the heavy-neutrino scale; i.e., more suppressed than the naive seesaw expectation. We classify the cases when this condition holds true in the minimal version of the seesaw model, showing its compatibility (1) with neutrinoless double beta rate being dominated by heavy neutrinos and (2) with any light neutrino mass spectra. The absence of excessive fine-tunings and the radiative stability of light neutrino mass matrices, together with a saturating sterile neutrino contribution, imply an upper bound on the heavy neutrino masses of about 10 GeV. We extend our analysis to the Extended seesaw scenario, where the light and the heavy sterile neutrino contributions are completely decoupled, allowing the sterile neutrinos to saturate the present experimental bound on neutrinoless double beta decay. In the models analyzed, the rate of this process is not strictly connected with the values of the light neutrino masses, and a fast transition rate is compatible with neutrinos lighter than 100 meV.

  2. Working group report: Neutrino and astroparticle physics

    Indian Academy of Sciences (India)

    Srubabati Goswami; Raghavan Rangarajan; K Agashe; A Bandyopadhyay; K Bhattacharya; B Brahmachari; C Burgess; E J Chun; D Choudhury; P K Das; A Dighe; A Godbole; S Goswami; N Gupta; M Kaplinghat; D Indumathi; J Forshaw; Y Y Keum; B Layek; D Majumdar; N Mahajan; P Mehta; R N Mohapatra; N Mondal; S More; N Nir; S Pakvasa; M K Parida; M Ravikumar; G Rajasekaran; P Ramadevi; R Rangarajan; S D Rindani; D P Roy; P Roy; N Sahu; A samanta; Y Shadmi; A M Srivastava; S Uma Sankar; R Vaidya; U Yajnik

    2004-12-01

    This is the report of neutrino and astroparticle physics working group at WHEPP-8. We present the discussions carried out during the workshop on selected topics in the above fields and also indicate progress made subsequently. The neutrino physics subgroup studied the possibilities of constraining neutrino masses, mixing and CPT violation in lepton sector from future experiments. Neutrino mass models in the context of Abelian horizontal symmetries, warped extra dimensions and in the presence of triplet Higgs were studied. Effect of threshold corrections on radiative magnification of mixing angles was investigated. The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation spectrum, and on brane cosmology. This report also contains an introduction on how to use the publicly available code CMBFAST to calculate the CMBR fluctuations.

  3. Probing large extra dimensions with neutrinos

    International Nuclear Information System (INIS)

    We study implications of theories with sub-millimeter extra dimensions and Mf∼(1-10) TeV scale quantum gravity for neutrino physics. In these theories, the left-handed neutrinos as well as other standard model (SM) particles, are localized on a brane embedded in the bulk of large extra space. Mixing of neutrinos with (SM) singlet fermions propagating in the bulk is naturally suppressed by the volume factor Mf/MP∼3·10-16-3·10-15, where MP is the Planck mass. Properties of the neutrino oscillations and the resonance conversion to the bulk fermions are considered. We show that the resonance conversion of the electron neutrinos to the light bulk fermions can solve the solar neutrino problem. The signature of the solution is the peculiar distortion of the solar neutrino spectrum. The solution implies that the radius of at least one extra dimension should be in the range 0.06-0.1 mm irrespective of total number of extra dimensions. The corresponding modification of the Newtonian law is within the range of sensitivity of proposed sub-millimeter experiments, thus providing a verifiable link between neutrino physics and the gravity measurements. (author)

  4. Ultra High Energy Neutrino Astronomy

    OpenAIRE

    Berezinsky, V.

    2005-01-01

    The short review of theoretical aspects of ultra high energy (UHE) neutrinos and superGZK neutrinos. The sources and diffuse fluxes of UHE neutrinos are discussed. Much attention is given to comparison of the cascade and cosmic ray upper bounds for diffuse neutrino fluxes. Cosmogenic neutrinos and neutrinos from the mirror mater are considered as superGZK neutrinos.

  5. Neutrino Oscillations Present Status and Future Plans

    CERN Document Server

    Thomas, Jennifer

    2008-01-01

    This book reviews the status of a very exciting field - neutrino oscillations - at a very important time. The fact that neutrinos have mass has only been proved in the last few years and the acceptance of that fact has opened up a whole new area of study to understand the fundamental parameters of the mixing matrix. The book summarizes the results from all the experiments which have played a role in the measurement of neutrino oscillations and briefly describes the scope of some new planned experiments. Contributions include a theoretical introduction by Stephen Parke from FNAL, as well as art

  6. Democratic-type neutrino mass matrix

    CERN Document Server

    Miura, T; Yoshimura, M; Miura, Takahiro; Takasugi, Eiichi; Yoshimura, Masaki

    2000-01-01

    We consider the democratic-type neutrino mass matrix and show that this matrix predicts the atmospheric neutrino mixing to be almost maximal, $\\sin^2 2\\theta_{atm}>0.999$ as well as the large CP violation (the CP violation phase in the standard form is maximal $\\delta=\\pi/2$). We construct the $Z_3$ symmetric dimension five effective Lagrangian with two up-type Higgs doublets and show that this Lagrangian leads to the democratic neutrino mass matrix. Furthermore, we consider the restricted model with one up-type Higgs doublet and obtain the prediction, $0.87<\\sin^2 2\\theta_{sol}<8/9$.

  7. Split neutrinos - leptogenesis, dark matter and inflation

    CERN Document Server

    Mazumdar, Anupam

    2012-01-01

    We propose a simple framework to split neutrinos with a slight departure from tribimaximal mixing - where two of the neutrinos are Majorana type which provide thermal leptogenesis. The Dirac neutrino with a tiny Yukawa coupling explains primordial inflation and the cosmic microwave background radiation, where the inflaton is the gauge invariant flat direction. The observed baryon asymmetry, and the scale of inflation are intimately tied to the observed reactor angle, which can be further constrained by the LHC and the neutrinoless double beta decay experiments. The model also provides the lightest right handed sneutrino as a part of the inflaton to be the dark matter candidate.

  8. History of "Anomalous" Atmospheric Neutrino Events: A First Person Account

    CERN Document Server

    LoSecco, John M

    2016-01-01

    The modern picture of the neutrino as a multiple mass highly mixed neutral particle has emerged over 40 years of study. Best known of the issues leading to this picture was the apparent loss of neutrinos coming from the sun. This article describes another piece of evidence that supports the picture; the substantial reduction of high energy muon type neutrinos observed in nature. For much of the 40 year period, before the modern picture emerged this observation was known as the "atmospheric neutrino anomaly", since as will be seen, these neutrinos originate in the Earth's atmosphere. This paper describes the discovery of the atmospheric neutrino anomaly. We explore the scientific context and motivations in the late 1970's from which this work emerged. The gradual awareness that the observations of atmospheric neutrinos were not as expected took place in the 1983-1986 period.

  9. FEASIBILITY STUDY II OF A MUON BASED NEUTRINO SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    GALLARDO,J.C.; OZAKI,S.; PALMER,R.B.; ZISMAN,M.

    2001-06-30

    The concept of using a muon storage ring to provide a well characterized beam of muon and electron neutrinos (a Neutrino Factory) has been under study for a number of years now at various laboratories throughout the world. The physics program of a Neutrino Factoryis focused on the relatively unexplored neutrino sector. In conjunction with a detector located a suitable distance from the neutrino source, the facility would make valuable contributions to the study of neutrino masses and lepton mixing. A Neutrino Factory is expected to improve the measurement accuracy of sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sup 2}{sub 32} and provide measurements of sin{sup 2}(2{theta}{sub 13}) and the sign of {Delta}m{sup 2}{sub 32}. It may also be able to measure CP violation in the lepton sector.

  10. Dark matter and IceCube neutrinos

    CERN Document Server

    Biondi, Riccardo

    2015-01-01

    We show that the excess of high energy neutrinos observed by the IceCube collaboration at energies above 100 TeV might originate from baryon number violating decays of heavy shadow baryons from mirror sector, which in turn constitute Dark Matter. Due to tiny mixing between mirror and ordinary neutrinos, it is possible to explain the specific features of the IceCube events spectrum.

  11. Supernova neutrino oscillations: What do we understand?

    Energy Technology Data Exchange (ETDEWEB)

    Dighe, Amol, E-mail: amol@theory.tifr.res.i [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2010-01-01

    We summarize our current understanding of the neutrino flavor conversions inside a core collapse supernova, clarifying the important role played by the 'collective effects' in determining flavor conversion probabilities. The potentially observable {nu}{sub e} and {nu}-bar {sub e} spectra may help us identify the neutrino mixing scenario, distinguish between primary flux models, and learn more about the supernova explosion.

  12. Light sterile neutrinos, lepton number violating interactions, and the LSND neutrino anomaly

    Science.gov (United States)

    Babu, K. S.; McKay, Douglas W.; Mocioiu, Irina; Pakvasa, Sandip

    2016-06-01

    We develop the consequences of introducing a purely leptonic, lepton number violating nonstandard interaction (NSI) and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short baseline, neutrino experiments. We focus on the muon decay at rest (DAR) results from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford Medium Energy Neutrino Experiment. We make a comprehensive analysis of lepton number violating, NSI effective operators and find nine that affect muon decay relevant to LSND results. Two of these preserve the standard model value 3 /4 for the Michel ρ and δ parameters and, overall, show favorable agreement with precision data and the ν¯e signal from LSND data. We display theoretical models that lead to these two effective operators. In the model we choose to apply to DAR data, both ν¯e appearance from ν¯μ oscillation and ν¯e survival after production from NSI decay of the μ+ contribute to the expected signal. This is a unique feature of our scheme. We find a range of parameters where both experiments can be accommodated consistently with recent global, sterile neutrino fits to short baseline data. We comment on implications of the models for new physics searches at colliders and comment on further implications of the lepton number violating interactions plus sterile neutrino-standard neutrino mixing.

  13. Measurement of Neutrino Oscillation Parameters from Muon Neutrino Disappearance with an Off-axis Beam

    CERN Document Server

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

    2013-01-01

    The T2K collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to $3.01 \\times 10^{20}$ protons on target. In the absence of neutrino oscillations, $205 \\pm 17$ (syst.) events are expected to be detected and only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum assuming three neutrino flavors, normal mass hierarchy and $\\theta_{23}\\leq \\pi/4$ yields a best-fit mixing angle $\\sin^2(2\\theta_{23})=1.000$ and mass splitting $|\\Delta m^2_{32}| =2.44 \\times 10^{-3}$ eV$^2$/c$^4$. If $\\theta_{23}\\geq \\pi/4$ is assumed, the best-fit mixing angle changes to $\\sin^2(2\\theta_{23})=0.999$ and the mass splitting remains unchanged.

  14. 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.

  15. Implications of Fermionic Dark Matter on recent neutrino oscillation data

    CERN Document Server

    Singirala, Shivaramakrishna

    2016-01-01

    We investigate flavor phenomenology and dark matter in the context of scotogenic model. In this model, the neutrino masses are generated through radiative corrections at one-loop level. Considering the neutrino mixing matrix to be of tri-bimaximal form with additional perturbations to accommodate the recently observed non-zero value of reactor mixing angle $\\theta_{13}$, we obtain the relation between various neutrino oscillation parameters and the model parameters. Working in degenerate heavy neutrino mass spectrum, we obtain light neutrino masses obeying normal heirarchy and also study the relic abundance of fermionic dark matter candidate including coannihilation effects. A viable parameter space is thus obtained, consistent with neutrino oscillation data, relic abundance and various lepton flavor violating decays such as $\\ell_\\alpha\\to\\ell_\\beta\\gamma$ and $\\ell_\\alpha \\to 3 \\, \\ell_\\beta$.

  16. Muons and Neutrinos 2007

    CERN Document Server

    Gaisser, Thomas K

    2008-01-01

    This paper is the written version of the rapporteur talk on Section HE-2, muons and neutrinos, presented at the 30th International Cosmic Ray Conference, Merida, Yucatan, July 11, 2007. Topics include atmospheric muons and neutrinos, solar neutrinos and astrophysical neutrinos as well as calculations and instrumentation related to these topics.

  17. Long Baseline Neutrino Oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Rebel, Brian; /Fermilab

    2009-10-01

    There is compelling evidence for neutrino flavor change as neutrinos propagate. The evidence for this phenomenon has been provided by several experiments observing neutrinos that traverse distances of several hundred kilometers between production and detection. This review outlines the evidence for neutrino flavor change from such experiments and describes recent results in the field.

  18. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

    J G Learned

    2000-07-01

    With the announcement of new evidence for muon neutrino disappearance observed by the super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an apparently inescapable fact. The evidence is reviewed, and new indications are presented that the oscillations are probably between muon and tau neutrinos. Implications and future directions are discussed.

  19. 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....

  20. Light Sterile Neutrinos

    CERN Document Server

    Giunti, Carlo

    2015-01-01

    The indications in favor of the existence of light sterile neutrinos at the eV scale found in short-baseline neutrino oscillation experiments is reviewed. The future perspectives of short-baseline neutrino oscillation experiments and the connections with beta-decay measurements of the neutrino masses and with neutrinoless double-beta decay experiments are discussed.