Sample records for neutrinos heavy leptons

  1. Prospects of Heavy Neutrino Searches at Future Lepton Colliders

    E-Print Network [OSTI]

    Banerjee, Shankha; Ibarra, Alejandro; Mandal, Tanumoy; Mitra, Manimala

    2015-01-01T23:59:59.000Z

    We discuss the future prospects of heavy neutrino searches at next generation lepton colliders. In particular, we focus on the planned electron-positron colliders, operating in two different beam modes, namely, $e^+e^-$ and $e^-e^-$. In the $e^+e^-$ beam mode, we consider various production and decay modes of the heavy neutrino ($N$), and find that the final state with $e+2j+\\slashed{E}$, arising from the $e^+e^-\\to N\

  2. Neutrino and it's lepton

    E-Print Network [OSTI]

    G. Quznetsov

    2008-11-10T23:59:59.000Z

    In this paper I cite p.p. 100-117 of book G. Quznetsov, Probabilistic Treatment of Gauge Theories, in series Contemporary Fundamental Physics,ed. V. Dvoeglazov, Nova Sci. Publ., NY (2007). There I research a bound between neutrino and it's lepton.

  3. Lepton textures and neutrino oscillations

    E-Print Network [OSTI]

    Verma, Rohit

    2014-01-01T23:59:59.000Z

    Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.

  4. Lepton textures and neutrino oscillations

    E-Print Network [OSTI]

    Rohit Verma

    2014-06-03T23:59:59.000Z

    Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.

  5. Lepton flavor violation decays with the fourth generation neutrino

    E-Print Network [OSTI]

    Wu-Jun Huo; Tai-Fu Feng

    2002-03-22T23:59:59.000Z

    We investigate the lepton flavor violation decays, $\\tau \\to \\mu\\gamma$, $\\tau \\to e\\gamma$ and $\\mu \\to e\\gamma$, in the framwork of a squential fourth generation model with a heavy fourth neutrino, $\

  6. Lepton Mass Hierarchy and Neutrino Oscillations

    E-Print Network [OSTI]

    H. Fritzsch; Z. Z Xing

    1995-09-26T23:59:59.000Z

    Starting from the symmetry of lepton flavor democracy, we propose and discuss a simple pattern for the mass generation and flavor mixing of the charged leptons and neutrinos. The three neutrino masses are nearly degenerate, and the flavor mixing angles can be calculated. The observed deficit of solar and atmospheric neutrinos can be interpreted as a consequence of the near degeneracy and large oscillations of $\

  7. Little Flavor: Heavy Leptons, Z' and Higgs Phenomenology

    E-Print Network [OSTI]

    Sichun Sun

    2014-12-01T23:59:59.000Z

    The Little Flavor model is a close cousin of the Little Higgs theory which aims to generate flavor structure around TeV scale. While the original Little Flavor only included the quark sector, here we build the lepton part of the Little Flavor model and explore its phenomenology. The model produces the neutrino mixing matrix and Majorana masses of the Standard Model neutrinos through coupling to heavy lepton partners and Little Higgses. We combine the usual right-handed seesaw mechanism with global symmetry protection to suppress the Standard Model neutrino masses, and identify the TeV partners of leptons as right-handed Majorana neutrinos. The lepton masses and mixing matrix are calculated perturbatively in the theory. The TeV new gauge bosons have suppressed decay width in dilepton channels. Even assuming the Standard Model couplings, the branching ratios to normal dilepton channels are largely reduced in the model, to evade the bound from current $Z'$ search. It also opens up the new search channels for exotic gauge bosons, especially Z' -> E_{t missing} + multi L. The multiple lepton partners will create new chain decay signals in flavor related processes in colliders, which also give rise to flavor anomalies. The lepton flavor violation process can be highly suppressed in charged lepton sector and happens only through neutrinos.

  8. Differentiating neutrino models on the basis of $\\theta_{13}$ and lepton flavor violation

    SciTech Connect (OSTI)

    Albright, Carl H.; /Northern Illinois U. /Fermilab

    2008-03-01T23:59:59.000Z

    The authors show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for {theta}{sub 13} and lepton flavor violation in radiative charged lepton decays and {mu} - e conversion. They illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and {theta}{sub 13} predictions.

  9. Unveiling neutrino mixing and leptonic CP violation

    SciTech Connect (OSTI)

    Mena, Olga; /Fermilab

    2005-01-01T23:59:59.000Z

    We review the present understanding of neutrino masses and mixings, discussing what are the unknowns in the three family oscillation scenario. Despite the anticipated success coming from the planned long baseline neutrino experiments in unraveling the leptonic mixing sector, there are two important unknowns which may remain obscure: the mixing angle {theta}{sub 13} and the CP-phase {delta}. The measurement of these two parameters has led us to consider the combination of superbeams and neutrino factories as the key to unveil the neutrino oscillation picture.

  10. Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices

    E-Print Network [OSTI]

    Fritzsch, Harald

    2012-01-01T23:59:59.000Z

    Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.

  11. Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices

    E-Print Network [OSTI]

    Harald Fritzsch; Shun Zhou

    2012-12-03T23:59:59.000Z

    Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.

  12. Lepton flavor violating Higgs boson decays from massive seesaw neutrinos

    SciTech Connect (OSTI)

    Arganda, Ernesto; Curiel, Ana M.; Herrero, Maria J.; Temes, David [Departamento de Fisica Teorica, Universidad Autonoma de Madrid (Spain); Laboratoire de Physique Theorique, LAPTH (France)

    2005-02-01T23:59:59.000Z

    Lepton flavor violating Higgs boson decays are studied within the context of seesaw models with Majorana massive neutrinos. Two models are considered: the SM-seesaw, with the standard model particle content plus three right-handed neutrinos, and the MSSM-seesaw, with the minimal supersymmetric standard model particle content plus three right-handed neutrinos and their supersymmetric partners. The widths for these decays are derived from a full one-loop diagrammatic computation in both models, and they are analyzed numerically in terms of the seesaw parameters, namely, the Dirac and Majorana mass matrices. Several possible scenarios for these mass matrices that are compatible with neutrino data are considered. In the SM-seesaw case, very small branching ratios are found for all studied scenarios. These ratios are explained as a consequence of the decoupling behavior of the heavy right-handed neutrinos. In contrast, in the MSSM-seesaw case, sizable branching ratios are found for some of the leptonic flavor violating decays of the MSSM neutral Higgs bosons and for some choices of the seesaw matrices and MSSM parameters. The relevance of the two competing sources of lepton flavor changing interactions in the MSSM-seesaw case is also discussed. The nondecoupling behavior of the supersymmetric particles contributing in the loop diagrams is finally shown.

  13. Neutrinoless Double Beta Decay and Heavy Sterile Neutrinos

    E-Print Network [OSTI]

    Manimala Mitra; Goran Senjanovic; Francesco Vissani

    2011-12-21T23:59:59.000Z

    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.

  14. Minimal Seesaw Textures with Two Heavy Neutrinos

    E-Print Network [OSTI]

    Srubabati Goswami; Atsushi Watanabe

    2008-08-06T23:59:59.000Z

    We systematically analyze the Dirac and the Majorana mass matrices in seesaw models with two heavy right-handed neutrinos. We perform thorough classification of the vanishing matrix elements which are compatible with the results from the current neutrino oscillation experiments. We include the possibility of a non-diagonal Majorana mass matrix which leads to new solutions viable with data. In a basis where the Majorana mass matrix is diagonal, these solutions imply a Dirac matrix with specific relationships amongst its elements. We find that at the level of total 4 zeros together in the Dirac and the Majorana sectors, the mass matrices are almost consistent with the data but one mixing angle is predicted to be unsuitable. At the next level, i.e. with total 3 zeros, only seven patterns of mass matrices describe the experimental data well. The seven solutions have testable predictions for the future neutrino experiments. In particular, each solution has definite predictions about the observation of the 1-3 leptonic mixing angle and the effective mass measured in neutrino-less double beta decay. The solutions of the mass matrices contain novel texture forms and provide new insights into the lepton-generation structure. We also discuss possible connections between these textures and the tri-bimaximal mixing to search for symmetry principles behind the mass matrix structure.

  15. Permutation symmetry for neutrino and charged-lepton mass matrices

    SciTech Connect (OSTI)

    Ma, Ernest [Physics Department, Univeristy of California, Riverside, California 92521 (United States)] [Physics Department, Univeristy of California, Riverside, California 92521 (United States)

    2000-02-01T23:59:59.000Z

    Permutation symmetry S{sub 3} is applied to obtain two equal Majorana neutrino masses, while maintaining three different charged-lepton masses and suppressing neutrinoless double beta decay. The resulting radiative splitting of the two neutrinos is shown to be suitable for solar neutrino vacuum oscillations. (c) 2000 The American Physical Society.

  16. Minimal seesaw textures with two heavy neutrinos

    SciTech Connect (OSTI)

    Goswami, Srubabati [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019 (India); Physical Research Laboratory, Navrangpura, Ahmedabad -380009 (India); Watanabe, Atsushi [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019 (India)

    2009-02-01T23:59:59.000Z

    We systematically analyze the Dirac and the Majorana mass matrices in seesaw models with two heavy right-handed neutrinos. We perform thorough classification of the vanishing matrix elements which are compatible with the results from the current neutrino oscillation experiments. We include the possibility of a nondiagonal Majorana mass matrix which leads to new solutions viable with data. In a basis where the Majorana mass matrix is diagonal, these solutions imply a Dirac matrix with specific relationships amongst its elements. We find that at the level of total four zeros together in m{sub D} and M{sub R} the mass matrices are almost consistent with the data but one mixing angle is predicted to be unsuitable. At the next level, i.e. with total three zeros, only seven patterns of mass matrices describe the experimental data well. The seven solutions have testable predictions for the future neutrino experiments. In particular, each solution has definite predictions about the observation of the 1-3 leptonic mixing angle and the effective mass measured in neutrinoless double beta decay. The solutions of the mass matrices contain novel texture forms and provide new insights into the lepton-generation structure. We also discuss possible connections between these textures and the tri-bimaximal mixing to search for symmetry principles behind the mass matrix structure.

  17. Testing solar lepton mixing sum rules in neutrino oscillation experiments

    E-Print Network [OSTI]

    Ballett, Peter; Luhn, Christoph; Pascoli, Silvia; Schmidt, Michael A

    2014-01-01T23:59:59.000Z

    Small discrete family symmetries such as S4, A4 or A5 may lead to simple leading-order predictions for the neutrino mixing matrix such as the bimaximal, tribimaximal or golden ratio mixing patterns, which may be brought into agreement with experimental data with the help of corrections from the charged-lepton sector. Such scenarios generally lead to relations among the parameters of the physical leptonic mixing matrix known as solar lepton mixing sum rules. In this article, we present a simple derivation of such solar sum rules, valid for arbitrary neutrino and charged lepton mixing angles and phases, assuming only {\\theta}13^{\

  18. Preon Trinity - A Schematic Model of Leptons, Quarks and Heavy Vector Bosons

    E-Print Network [OSTI]

    Jean-Jacques Dugne; Sverker Fredriksson; Johan Hansson

    2002-08-14T23:59:59.000Z

    Quarks, leptons and heavy vector bosons are suggested to be composed of stable spin-1/2 preons, existing in three flavours, combined according to simple rules. Straightforward consequences of an SU(3) preon-flavour symmetry are the conservation of three lepton numbers, oscillations and decays between some neutrinos, and the mixing of the d and s quarks, as well as of the vector fields W^0 and B^0. We find a relation between the Cabibbo and Weinberg mixing angles, and predict new (heavy) leptons, quarks and vector bosons, some of which might be observable at the Fermilab Tevatron and the future CERN LHC. A heavy neutrino might even be visible in existing data from the CERN LEP facility.

  19. Neutrino mass hierarchy and the origin of leptonic flavor mixing from the righthanded sector

    E-Print Network [OSTI]

    Leser, Philipp

    2011-01-01T23:59:59.000Z

    We consider a neutrino mass model where all leptonic mixing is induced by a heavy Majorana sector through the seesaw type I mechanism, while the Dirac mass matrices are diagonal. Such a pattern occurs naturally in Grand Unified Theories (GUTs). Constraints on the parameters of the models are considered and it is shown that a normal neutrino mass hierarchy is preferred. The lightest neutrino mass is typically small, leading to non-observable rates for neutrinoless double beta decay in the normal hierarchy case.

  20. Nuclear PDF for neutrino and charged lepton data

    E-Print Network [OSTI]

    K. Kovarik

    2010-12-13T23:59:59.000Z

    Neutrino Deep Inelastic Scattering on nuclei is an essential process to constrain the strange quark parton distribution functions in the proton. The critical component on the way to using the neutrino DIS data in a proton PDF analysis is understanding the nuclear effects in parton distribution functions. We parametrize these effects by nuclear parton distribution functions. Here we compare results from two analysis of NPDF both done at next-to-leading order in QCD. The first uses neutral current charged-lepton lA Deeply Inelastic Scattering and Drell-Yan data for several nuclear targets and the second uses neutrino-nucleon DIS data. We compare the nuclear corrections factors F_2^Fe/F_2^D for the charged-lepton data with other results from the literature. In particular, we compare and contrast fits based upon the charged-lepton DIS data with those using neutrino-nucleon DIS data.

  1. Neutrino Masses, Lepton Flavor Mixing and Leptogenesis in the Minimal Seesaw Model

    E-Print Network [OSTI]

    Wan-lei Guo; Zhi-zhong Xing; Shun Zhou

    2006-12-05T23:59:59.000Z

    We present a review of neutrino phenomenology in the minimal seesaw model (MSM), an economical and intriguing extension of the Standard Model with only two heavy right-handed Majorana neutrinos. Given current neutrino oscillation data, the MSM can predict the neutrino mass spectrum and constrain the effective masses of the tritium beta decay and the neutrinoless double-beta decay. We outline five distinct schemes to parameterize the neutrino Yukawa-coupling matrix of the MSM. The lepton flavor mixing and baryogenesis via leptogenesis are investigated in some detail by taking account of possible texture zeros of the Dirac neutrino mass matrix. We derive an upper bound on the CP-violating asymmetry in the decay of the lighter right-handed Majorana neutrino. The effects of the renormalization-group evolution on the neutrino mixing parameters are analyzed, and the correlation between the CP-violating phenomena at low and high energies is highlighted. We show that the observed matter-antimatter asymmetry of the Universe can naturally be interpreted through the resonant leptogenesis mechanism at the TeV scale. The lepton-flavor-violating rare decays, such as $\\mu \\to e + \\gamma$, are also discussed in the supersymmetric extension of the MSM.

  2. Discriminating among the theoretical origins of new heavy Majorana neutrinos at the CERN LHC

    E-Print Network [OSTI]

    F. M. L. de Almeida Jr.; Y. A. Coutinho; J. A. Martins Simoes; A. J. Ramalho; S. Wulck; M. A. B. do Vale

    2007-03-08T23:59:59.000Z

    A study on the possibility of distinguishing new heavy Majorana neutrino models at LHC energies is presented. The experimental confirmation of standard neutrinos with non-zero mass and the theoretical possibility of lepton number violation find a natural explanation when new heavy Majorana neutrinos exist. These new neutrinos appear in models with new right-handed singlets, in new doublets of some grand unified theories and left-right symmetrical models. It is expected that signals of new particles can be found at the CERN high-energy hadron collider (LHC). We present signatures and distributions that can indicate the theoretical origin of these new particles. The single and pair production of heavy Majorana neutrinos are calculated and the model dependence is discussed. Same-sign dileptons in the final state provide a clear signal for the Majorana nature of heavy neutrinos, since there is lepton number violation. Mass bounds on heavy Majorana neutrinos allowing model discrimination are estimated for three different LHC luminosities.

  3. Nearly degenerate heavy sterile neutrinos in cascade decay: mixing and oscillations

    E-Print Network [OSTI]

    Boyanovsky, Daniel

    2014-01-01T23:59:59.000Z

    Some extensions beyond the Standard Model propose the existence of nearly degenerate heavy sterile neutrinos. If kinematically allowed these can be resonantly produced and decay in a cascade to common final states. The common decay channels lead to mixing of the heavy sterile neutrino states and interference effects. We implement non-perturbative methods to study the dynamics of the cascade decay to common final states, which features similarities but also noteworthy differences with the case of neutral meson mixing. We show that mixing and oscillations among the nearly degenerate sterile neutrinos can be detected as \\emph{quantum beats} in the distribution of final states produced from their decay. These oscillations would be a telltale signal of mixing between heavy sterile neutrinos. We study in detail the case of two nearly degenerate sterile neutrinos produced in the decay of pseudoscalar mesons and decaying into a purely leptonic "visible" channel: $\

  4. Nearly degenerate heavy sterile neutrinos in cascade decay: mixing and oscillations

    E-Print Network [OSTI]

    Daniel Boyanovsky

    2014-11-20T23:59:59.000Z

    Some extensions beyond the Standard Model propose the existence of nearly degenerate heavy sterile neutrinos. If kinematically allowed these can be resonantly produced and decay in a cascade to common final states. The common decay channels lead to mixing of the heavy sterile neutrino states and interference effects. We implement non-perturbative methods to study the dynamics of the cascade decay to common final states, which features similarities but also noteworthy differences with the case of neutral meson mixing. We show that mixing and oscillations among the nearly degenerate sterile neutrinos can be detected as \\emph{quantum beats} in the distribution of final states produced from their decay. These oscillations would be a telltale signal of mixing between heavy sterile neutrinos. We study in detail the case of two nearly degenerate sterile neutrinos produced in the decay of pseudoscalar mesons and decaying into a purely leptonic "visible" channel: $\

  5. Neutrino masses and mixing, quark-lepton symmetry, and strong right-handed neutrino hierarchy

    SciTech Connect (OSTI)

    Dermisek, Radovan [Davis Institute for High Energy Physics, University of California, Davis, California 95616 (United States)

    2004-10-01T23:59:59.000Z

    Assuming the same form of all mass matrices as motivated by quark-lepton symmetry, we discuss conditions under which bilarge mixing in the lepton sector can be obtained with a minimal amount of fine-tuning requirements for possible models. We assume hierarchical mass matrices, dominated by the 3-3 element, with off-diagonal elements much smaller than the larger neighboring diagonal element. Characteristic features of this scenario are strong hierarchy in masses of right-handed neutrinos, and comparable contributions of both lighter right-handed neutrinos to the resulting left-handed neutrino Majorana mass matrix. Because of obvious quark-lepton symmetry, this approach can be embedded into grand unified theories. The mass of the lightest neutrino does not depend on details of a model in the leading order. The right-handed neutrino scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as (m{sub top}{sup 2}/M{sub GUT}) vertical bar U{sub {tau}}{sub 1} vertical bar{sup 2}.

  6. Lepton number violating processes mediated by Majorana neutrinos at hadron colliders

    SciTech Connect (OSTI)

    Kovalenko, Sergey; Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico, Santa Maria, Casilla 110-V, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)

    2009-10-01T23:59:59.000Z

    We study the lepton number violating like-sign dilepton processes h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}jjX and h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}W{sup {+-}}X, mediated by heavy GeV scale Majorana neutrinos. We focus on the resonantly enhanced contributions with a nearly on-mass-shell Majorana neutrino in the s channel. We study the constraints on like-sign dilepton production at the Tevatron and the LHC on the basis of the existing experimental limits on the masses of heavy neutrinos and their mixings U{sub {alpha}}{sub N} with {alpha}={nu}{sub e}, {nu}{sub {mu}}, {nu}{sub {tau}}. Special attention is paid to the constraints from neutrinoless double beta decay. We note that searches for like-sign e{sup {+-}}e{sup {+-}} events at Tevatron and LHC may provide evidence of CP violation in the neutrino sector. We also discuss the conditions under which it is possible to extract individual constraints on the mixing matrix elements in a model independent way.

  7. Detecting exotic heavy leptons at the large hadron collider.

    E-Print Network [OSTI]

    Allanach, B C; Harris, Chris M; Parker, Michael A; Richardson, P; Webber, Bryan R

    the cuts actually slightly increases with mass due to the longer time delays. 0.01 0.1 1 10 100 1000 100 200 300 400 500 600 700 800 900 1000 Cr os s se ct io n (fb ) Mass of heavy lepton (GeV) Before applying cuts After applying cuts Figure 5: Cross...

  8. Almost Maximal Lepton Mixing with Large T Violation in Neutrino Oscillations and Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    Zhi-zhong Xing

    2001-07-02T23:59:59.000Z

    We point out two simple but instructive possibilities to construct the charged lepton and neutrino mass matrices, from which the nearly bi-maximal neutrino mixing with large T violation can naturally emerge. The two lepton mixing scenarios are compatible very well with current experimental data on solar and atmospheric neutrino oscillations, and one of them may lead to an observable T-violating asymmetry between \

  9. Heavy neutrinos and the $pp\\to lljj$ CMS data

    E-Print Network [OSTI]

    Gluza, J

    2015-01-01T23:59:59.000Z

    We show that the excess in the $pp \\to ee jj$ CMS data can be naturally interpreted within the Minimal Left Right Symmetric model (MLRSM), keeping $g_L = g_R$, if CP phases and non-degenerate masses of heavy neutrinos are taken into account. As an additional benefit, a natural interpretation of the reported ratio (14:1) of the opposite-sign (OS) $pp\\to l^\\pm l^\\mp jj$ to the same-sign (SS) $pp\\to l^\\pm l^\\pm jj$ lepton signals is possible. Finally, a suppression of muon pairs with respect to electron pairs in the $pp \\to lljj$ data is obtained, in accordance with experimental data. If the excess in the CMS data survives in the future, it would be a first clear hint towards presence of heavy neutrinos in right-handed charged currents with specific CP phases, mixing angles and masses, which will have far reaching consequences for particle physics directions.

  10. Lepton mixing under the lepton charge nonconservation, neutrino masses and oscillations and the 'forbidden' decay Micro-Sign {sup -} {yields} e{sup -} + {gamma}

    SciTech Connect (OSTI)

    Lyuboshitz, V. L.; Lyuboshitz, V. V., E-mail: Valery.Lyuboshitz@jinr.ru [Joint Institute for Nuclear Research (Russian Federation)

    2013-08-15T23:59:59.000Z

    The lepton-charge (L{sub e}, L{sub {mu}}, L{sub {tau}}) nonconserving interaction leads to the mixing of the electron, muon, and tau neutrinos, which manifests itself in spatial oscillations of a neutrino beam, and also to the mixing of the electron, negative muon, and tau lepton, which, in particular, may be the cause of the 'forbidden' radiative decay of the negative muon into the electron and {gamma} quantum. Under the assumption that the nondiagonal elements of the mass matrices for neutrinos and ordinary leptons, connected with the lepton charge nonconservation, are the same, and by performing the joint analysis of the experimental data on neutrino oscillations and experimental restriction for the probability of the decay Micro-Sign {sup -} {yields} e{sup -} + {gamma} per unit time, the following estimate for the lower bound of neutrino mass has been obtained: m{sup ({nu})} > 1.5 eV/c{sup 2}.

  11. CPT and lepton number violation in neutrino sector: Modified mass matrix and oscillation due to gravity

    E-Print Network [OSTI]

    Monika Sinha; Banibrata Mukhopadhyay

    2007-11-21T23:59:59.000Z

    We study the consequences of CPT and lepton number violation in neutrino sector. For CPT violation we take gravity with which neutrino and antineutrino couple differently. Gravity mixes neutrino and antineutrino in an unequal ratio to give two mass eigenstates. Lepton number violation interaction together with CPT violation gives rise to neutrino-antineutrino oscillation. Subsequently, we study the neutrino flavor mixing and oscillation under the influence of gravity. It is found that gravity changes flavor oscillation significantly which influences the relative abundance of different flavors in present universe. We show that the neutrinoless double beta decay rate is modified due to presence of gravity- the origin of CPT violation, as the mass of the flavor state is modified.

  12. Leptogenesis and low energy CP phases with two heavy neutrinos

    SciTech Connect (OSTI)

    Bhattacharya, Kaushik; Sahu, Narendra; Sarkar, Utpal; Singh, Santosh K. [Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380 009 (India)

    2006-11-01T23:59:59.000Z

    An attractive explanation for nonzero neutrino masses and small matter antimatter asymmetry of the present Universe lies in 'leptogenesis'. At present the size of the lepton asymmetry is precisely known, while the sign is not known yet. In this work we determine the sign of this asymmetry in the framework of two right-handed neutrino models by relating the leptogenesis phase(s) with the low energy CP violating phases appearing in the leptonic mixing matrix. It is shown that the knowledge of low energy lepton number violating rephasing invariants can indeed determine the sign of the present matter antimatter asymmetry of the Universe and hence indirectly probing the light physical neutrinos to be Majorana type.

  13. Dynamical evolution of neutrino--cooled accretion disks: detailed microphysics, lepton-driven convection, and global energetics

    E-Print Network [OSTI]

    William H. Lee; Enrico Ramirez-Ruiz; Dany Page

    2005-06-06T23:59:59.000Z

    We present a detailed, two dimensional numerical study of the microphysical conditions and dynamical evolution of accretion disks around black holes when neutrino emission is the main source of cooling. Such structures are likely to form after the gravitational collapse of massive rotating stellar cores, or the coalescence of two compact objects in a binary (e.g., the Hulse--Taylor system). The physical composition is determined self consistently by considering two regimes: neutrino--opaque and neutrino--transparent, with a detailed equation of state which takes into account neutronization, nuclear statistical equilibrium of a gas of free nucleons and alpha particles, blackbody radiation and a relativistic Fermi gas of arbitrary degeneracy. Various neutrino emission processes are considered, with electron/positron capture onto free nucleons providing the dominant contribution to the cooling rate. We find that important temporal and spatial scales, related to the optically thin/optically thick transition are present in the disk, and manifest themselves clearly in the energy output in neutrinos. This transition produces an inversion of the lepton gradient in the innermost regions of the flow which drives convective motions, and affects the density and disk scale height radial profiles. The electron fraction remains low in the region close to the black hole, and if preserved in an outflow, could give rise to heavy element nucleosynthesis. Our specific initial conditions arise from the binary merger context, and so we explore the implications of our results for the production of gamma ray bursts.

  14. Signature of heavy Majorana neutrinos at a linear collider: Enhanced charged Higgs pair production

    SciTech Connect (OSTI)

    Atwood, David [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Bar-Shalom, Shaouly [Physics Department, Technion-Institute of Technology, Haifa 32000 (Israel); Soni, Amarjit [Theory Group, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2007-08-01T23:59:59.000Z

    A charged Higgs pair can be produced at an ee collider through a t-channel exchange of a heavy neutrino (N) via e{sup +}e{sup -}{yields}H{sup +}H{sup -} and, if N is a Majorana particle, also via the lepton number violating (LNV) like-sign reaction e{sup {+-}}e{sup {+-}}{yields}H{sup {+-}}H{sup {+-}}. Assuming no a priori relation between the effective eNH{sup +} coupling ({xi}) and light neutrino masses, we show that this interaction vertex can give a striking enhancement to these charged Higgs pair production processes. In particular, the LNV H{sup -}H{sup -} signal can probe N at the International Linear Collider (ILC) in the mass range 100 GeV < or approx. m{sub N} < or approx. 10{sup 4} TeV and with the effective mixing angle {xi} in the range 10{sup -4} < or approx. {xi}{sup 2} < or approx. 10{sup -8}--well within its perturbative unitarity bound and the {beta}{beta}{sub 0{nu}} limit. The lepton number conserving e{sup +}e{sup -}{yields}H{sup +}H{sup -} mode can be sensitive to, e.g., an O(10) TeV heavy Majorana neutrino at a 500 GeV ILC, if {xi}{sup 2} > or approx. 0.001.

  15. Dark Matter and Lepton Flavour Violation in a Hybrid Neutrino Mass Model

    E-Print Network [OSTI]

    Deppisch, Frank F

    2014-01-01T23:59:59.000Z

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

  16. Seesaw enhancement of lepton mixing

    SciTech Connect (OSTI)

    Smirnov, A.Y. (Institute for Advanced Study, Princeton, New Jersey 08540 (United States) International Centre for Theoretical Physics, 34100 Trieste (Italy) Institute for Nuclear Research, 117312 Moscow (Russian Federation))

    1993-10-01T23:59:59.000Z

    The seesaw mechanism of neutrino mass generation may enhance lepton mixing up to maximal even if the Dirac mass matrices of leptons have a structure similar to that in the quark sector. Two sets of conditions for such an enhancement are found. The first one includes the seesaw generation of heavy Majorana masses for right-handed neutrinos and a universality of Yukawa couplings which can follow from the unification of neutrinos with new superheavy neutral leptons. The second set is related to the lepton number symmetry of the Yukawa interactions in the Dirac basis of neutrinos. Models which realize these conditions have a strong hierarchy or strong degeneration of Majorana masses of the right-handed neutrinos.

  17. Heavy Sterile Neutrinos and Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    P. Bamert; C. P. Burgess; R. N. Mohapatra

    1994-10-12T23:59:59.000Z

    We investigate the possibility of producing neutrinoless double beta decay without having an electron neutrino with a mass in the vicinity of 1 eV. We do so by having a much lighter electron neutrino mix with a much heavier (m > 1 GeV) sterile neutrino. We study the constraints on the masses and mixings of such heavy sterile neutrinos from existing laboratory, astrophysical and cosmological information, and discuss the properties it would require in order to produce a detectable signal in current searches for neutrinoless double beta decay.

  18. Neutrino Mass Matrix from Seesaw Mechanism with Heavy Majorana Neutrino Subject to Texture Zero and Invariant Under a Cyclic Permutation

    E-Print Network [OSTI]

    Asan Damanik; Mirza Satriawan; Pramudita Anggraita; Arief Hermanto; Muslim

    2007-12-13T23:59:59.000Z

    We evaluate the predictive power of the neutrino mass matrices arising from seesaw mechanism with heavy Majorana mass matrices subject to texture zero and satisfy a cyclic permutation invariant form to the solar neutrino mixing phenomena. From eight possible patterns of heavy Majorana neutrino mass matrix, we found that there is no heavy Majorana neutrino mass matrix to be invariant in form under a cyclic permutation. But, by imposing an additional assumption that at least one of the 2x2 sub-matrices of heavy Majorana neutrino mass matrix inverse having zero determinant, we found that only two of the eight possible patterns for heavy Majorana neutrino mass matrices to be invariant under a cyclic permutation. One of the two invariant heavy Majorana neutrino mass matrices could produces neutrino mass matrix $M_{\

  19. Search for Heavy Majorana Neutrinos in ?[superscript ±]?[superscript ±] + just and e[superscript ±]e[superscript ±] + jets events in pp collisions at ?s = 7 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    A search is performed for heavy Majorana neutrinos (N) using an event signature defined by two same-sign charged leptons of the same flavour and two jets. The data correspond to an integrated luminosity of 4.98 fb[superscript ...

  20. Upper limits on electric dipole moments of tau-lepton, heavy quarks, and W-boson

    E-Print Network [OSTI]

    A. G. Grozin; I. B. Khriplovich; A. S. Rudenko

    2009-03-04T23:59:59.000Z

    We discuss upper limits on the electric dipole moments (EDM) of the tau-lepton, heavy quarks, and W-boson, which follow from the precision measurements of the electron and neutron EDM.

  1. Upper limits on electric dipole moments of tau-lepton, heavy quarks, and W-boson

    E-Print Network [OSTI]

    Grozin, A G; Rudenko, A S

    2009-01-01T23:59:59.000Z

    We discuss upper limits on the electric dipole moments (EDM) of the tau-lepton, heavy quarks, and W-boson, which follow from the precision measurements of the electron and neutron EDM.

  2. Neutrino properties deduced from the study of lepton number violating processes at low and high energies

    SciTech Connect (OSTI)

    Stoica, Sabin [Horia Hulubei Foundation, P.O. Box MG-12, 077125 Magurele-Bucharest (Romania) and Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Magurele-Bucharest 077125 (Romania)

    2012-11-20T23:59:59.000Z

    There is nowadays a significant progress in understanding the neutrino properties. The results of the neutrino oscillation experiments have convincingly showed that neutrinos have mass and oscillate, in contradiction with the Standard Model (SM) assumptions, and these are the first evidences of beyond SM physics. However, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Majorana particles?), their mass hierarchy, the number of neutrino flavors, etc., still remain unknown. In this context there is an increased interest in the study of the lepton number violating (LNV) processes, since they could complete our understanding on the neutrino properties. Since recently, the neutrinoless double beta decay was considered the only process able to distinguish between Dirac or Majorana neutrinos and to give a hint on the absolute mass of the electron neutrino. At present, the increased luminosity of the LHC experiments makes feasible the search of LNV processes at high energy as well. In this lecture I will make a brief review on our present knowledge of the neutrino properties, on the present status of the double-beta decay studies and on the first attempts to search LNV processes at LHC.

  3. Neutrino mass, lepton number, and the origin of matter

    E-Print Network [OSTI]

    antiparticles? And many other things% Do neutrinos violate CP? #12;Neutrinoless Double Beta Decay W. Rodejohann? #12;Neutrinoless Double Beta Decay 1 sigma W. Rodejohann, 1206.2560 #12;14 F. Iachello #12;15 Regions

  4. Quasidegeneracy of Majorana Neutrinos and the Origin of Large Leptonic Mixing

    E-Print Network [OSTI]

    G. C. Branco; M. N. Rebelo; J. I. Silva-Marcos; Daniel Wegman

    2015-02-20T23:59:59.000Z

    We propose that the observed large leptonic mixing may just reflect a quasidegeneracy of three Majorana neutrinos. The limit of exact degeneracy of Majorana neutrinos is not trivial, as leptonic mixing and even CP violation may occur. We conjecture that the smallness of $|U_{13}|$, when compared to the other elements of $U_{PMNS}$, may just reflect the fact that, in the limit of exact mass degeneracy, the leptonic mixing matrix necessarily has a vanishing element. We show that the lifting of the mass degeneracy can lead to the measured value of $|U_{13}|$ while at the same time accommodating the observed solar and atmospheric mixing angles. In the scenario we consider for the breaking of the mass degeneracy there is only one CP violating phase, already present in the limit of exact degeneracy, which upon the lifting of the degeneracy generates both Majorana and Dirac-type CP violation in the leptonic sector. We analyse some of the correlations among physical observables and point out that in most of the cases considered, the implied strength of leptonic Dirac-type CP violation is large enough to be detected in the next round of experiments.

  5. Tau decays into three charged leptons and two neutrinos

    E-Print Network [OSTI]

    Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Copty, N.; Davis, Robin E. P.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan

    1996-04-01T23:59:59.000Z

    We search for the radiative leptonic tau decays tau --> ee(+) e(-)nu(tau)nu(e) and tau --> mu e(+)e(-)nu(tau)nu(mu) using 3.60 fb(-1) of data collected by the CLEO-II experiment at the Cornell Electron Storage Ring. We present a first observation...

  6. Leptogenesis from right-handed neutrino decays to right-handed leptons

    E-Print Network [OSTI]

    Thomas Hambye

    2006-06-16T23:59:59.000Z

    We investigate what would be the consequences for leptogenesis of the existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar particle exists, it allows the right-handed neutrinos to couple not only to left-handed lepton and Higgs doublets as in ordinary leptogenesis, but also to a right-handed charged lepton and a delta^+. This provides a new source of leptogenesis which can be successful in a non-resonant way at scales as low as TeV. The incorporation of this scenario in left-right symmetric and unified models is discussed.

  7. Giant Liquid Argon Observatory for Proton Decay, Neutrino Astrophysics and CP-violation in the Lepton Sector (GLACIER)

    E-Print Network [OSTI]

    Badertscher, A; Degunda, U; Epprecht, L; Horikawa, S; Knecht, L; Lazzaro, C; Lussi, D; Marchionni, A; Natterer, G; Otiougova, P; Resnati, F; Rubbia, A; Strabel, C; Ulbricht, J; Viant, T

    2010-01-01T23:59:59.000Z

    GLACIER (Giant Liquid Argon Charge Imaging ExpeRiment) is a large underground observatory for proton decay search, neutrino astrophysics and CP-violation studies in the lepton sector. Possible underground sites are studied within the FP7 LAGUNA project (Europe) and along the JPARC neutrino beam in collaboration with KEK (Japan). The concept is scalable to very large masses.

  8. Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background

    E-Print Network [OSTI]

    George M. Fuller; Chad T. Kishimoto; Alexander Kusenko

    2011-10-28T23:59:59.000Z

    We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the early universe with temperatures T > 1 GeV, but in a range to give decay lifetimes from seconds to minutes. Such neutrinos would decouple early, with relic densities comparable to those of photons, but decay out of equilibrium, with consequent prodigious entropy generation prior to, or during, Big Bang Nucleosynthesis (BBN). Most of the ranges of sterile neutrino rest mass and lifetime considered are at odds with Cosmic Microwave Background (CMB) limits on the relativistic particle contribution to energy density (e.g., as parameterized by N_eff). However, some sterile neutrino parameters can lead to an acceptable N_eff. These parameter ranges are accompanied by considerable dilution of the ordinary background relic neutrinos, possibly an adverse effect on BBN, but sometimes fall in a range which can explain measured neutrino masses in some particle physics models. A robust signature of these sterile neutrinos would be a measured N_eff not equal to 3 coupled with no cosmological signal for neutrino rest mass when the detection thresholds for these probes are below laboratory-established neutrino mass values, either as established by the atmospheric neutrino oscillation scale or direct measurements with, e.g., KATRIN or neutrino-less double beta decay experiments.

  9. Updated fit to three neutrino mixing: status of leptonic CP violation

    E-Print Network [OSTI]

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

    2014-12-16T23:59:59.000Z

    We present a global analysis of solar, atmospheric, reactor and accelerator neutrino data in the framework of three-neutrino oscillations based on data available in summer 2014. We provide the allowed ranges of the six oscillation parameters and show that their determination is stable with respect to uncertainties related to reactor neutrino and solar neutrino flux predictions. We find that the maximal possible value of the Jarlskog invariant in the lepton sector is $0.0329 \\pm 0.0009$ ($\\pm 0.0027$) at the $1\\sigma$ ($3\\sigma$) level and we use leptonic unitarity triangles to illustrate the ability of global oscillation data to obtain information on CP violation. We discuss "tendencies and tensions" of the global fit related to the octant of $\\theta_{23}$ as well as the CP violating phase $\\delta_\\mathrm{CP}$. The favored values of $\\delta_\\mathrm{CP}$ are around $3\\pi/2$ while values around $\\pi/2$ are disfavored at about $\\Delta\\chi^2 \\simeq 6$. We comment on the non-trivial task to assign a confidence level to this $\\Delta\\chi^2$ value by performing a Monte Carlo study of T2K data.

  10. Neutrino mixings and leptonic CP violation from CKM matrix and Majorana phases

    SciTech Connect (OSTI)

    Agarwalla, Sanjib Kumar; Parida, M. K.; Mohapatra, R. N.; Rajasekaran, G. [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Institute of Mathematical Sciences, Chennai 600113 (India)

    2007-02-01T23:59:59.000Z

    The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale the quark and lepton mixing matrices are equal, then for quasidegenerate neutrinos radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasidegenerate neutrinos could, within this framework, be interpreted as being consistent with quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP-violating phases (which were set to zero in the first paper). In the case where the Pontecorvo-Maki-Nakagawa-Sakata matrix is identical to the Cabibbo-Kobayashi-Maskawa quark-mixing matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ({approx_equal}0.3 deg.) and leptonic CP-violation parameter J{sub CP}{approx_equal}(4-8)x10{sup -5} and {theta}{sub 13}=3.5 deg. If on the other hand, the Pontecorvo-Maki-Nakagawa-Sakata matrix is assumed to also have non-negligible Majorana phase(s) initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has {theta}{sub 13}=3.5 deg. -10 deg. and vertical bar J{sub CP} vertical bar as large as 0.02-0.04 which are accessible to long baseline neutrino oscillation experiments.

  11. Neutrino Mixings and Leptonic CP Violation from CKM Matrix and Majorana Phases

    E-Print Network [OSTI]

    S. K. Agarwalla; M. K. Parida; R. N. Mohapatra; G. Rajasekaran

    2007-04-11T23:59:59.000Z

    The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale, the quark and lepton mixing matrices are equal then for quasi-degenerate neutrinos, radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasi-degenerate neutrinos could, within this framework, be interpreted as a sign of quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP violating phases (which were set to zero in the first paper). In the case where the PMNS matrix is identical to the CKM matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ($\\simeq 0.3^{\\circ}$) and leptonic CP-violation parameter $J_{CP} \\simeq (4 - 8)\\times 10^{-5}$ and $\\theta_{13} = 3.5^{\\circ}$. If on the other hand, the PMNS matrix is assumed to also have Majorana phases initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has $\\theta_{13} = 3.5^{\\circ} - 10^{\\circ}$ and $|J_{CP}|$ as large as $0.02-0.04$ which are accessible to long baseline neutrino oscillation experiments.

  12. Neutrino-driven wind simulations and nucleosynthesis of heavy elements

    E-Print Network [OSTI]

    A. Arcones; F. -K. Thielemann

    2012-07-11T23:59:59.000Z

    Neutrino-driven winds, which follow core-collapse supernova explosions, present a fascinating nuclear astrophysics problem that requires understanding advanced astrophysics simulations, the properties of matter and neutrino interactions under extreme conditions, the structure and reactions of exotic nuclei, and comparisons against forefront astronomical observations. The neutrino-driven wind has attracted vast attention over the last 20 years as it was suggested to be a candidate for the astrophysics site where half of the heavy elements are produced via the r-process. In this review, we summarize our present understanding of neutrino-driven winds from the dynamical and nucleosynthesis perspectives. Rapid progress has been made during recent years in understanding the wind with improved simulations and better micro physics. The current status of the fields is that hydrodynamical simulations do not reach the extreme conditions necessary for the r-process and the proton or neutron richness of the wind remains to be investigated in more detail. However, nucleosynthesis studies and observations point already to neutrino-driven winds to explain the origin of lighter heavy elements, such as Sr, Y, Zr.

  13. Neutrino Masses via a Seesaw with Heavy Majorana and Dirac Neutrino Mass Matrices from Discrete Subgroup $?(27)$ of SU(3)

    E-Print Network [OSTI]

    Asan Damanik

    2010-11-25T23:59:59.000Z

    Neutrino mass matrix via a seesaw mechanism is constructed by assuming that the underlying symmetry of both heavy Majorana and Dirac mass matrices is the discrete subgroup $\\Delta(27)$ symmetry of SU(3). Using the experimental data of neutrino oscillation, the neutrino mass matrix exhibits maximal $\

  14. Non-perturbative Heavy Quark Effective Theory: An application to semi-leptonic B-decays

    E-Print Network [OSTI]

    Michele Della Morte; Jochen Heitger; Hubert Simma; Rainer Sommer

    2015-01-14T23:59:59.000Z

    We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays at the leading order in 1/m_h.

  15. Probing long-range leptonic forces with solar and reactor neutrinos

    E-Print Network [OSTI]

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

    2007-01-01T23:59:59.000Z

    In this work we study the phenomenological consequences of the existence of long-range forces coupled to lepton flavour numbers in solar neutrino oscillations. We study electronic forces mediated by scalar, vector or tensor neutral bosons and analyze their effect on the propagation of solar neutrinos as a function of the force strength and range. Under the assumption of one mass scale dominance, we perform a global analysis of solar and KamLAND neutrino data which depends on the two standard oscillation parameters, \\Delta m^2_{21} and \\tan^2\\theta_{12}, the force coupling constant, its range and, for the case of scalar-mediated interactions, on the neutrino mass scale as well. We find that, generically, the inclusion of the new interaction does not lead to a very statistically significant improvement on the description of the data in the most favored MSW LMA (or LMA-I) region. It does, however, substantially improve the fit in the high-\\Delta m^2 LMA (or LMA-II) region which can be allowed for vector and scal...

  16. A minimal and predictive $T_7$ lepton flavor 331 model

    E-Print Network [OSTI]

    Hernández, A E Cárcamo

    2015-01-01T23:59:59.000Z

    We present a model based on the $SU(3)_{C}\\otimes SU(3)_{L}\\otimes U(1)_{X}$ gauge group having an extra $T_{7}\\otimes Z_{3}\\otimes Z_{14}$ flavor group, where the light active neutrino masses arise via double seesaw mechanism and the observed charged lepton mass hierarchy is a consequence of the $Z_{14}$ symmetry breaking at very high energy. In our minimal and predictive $T_7$ lepton flavor 331 model, the spectrum of neutrinos includes very light active neutrinos and heavy and very heavy sterile neutrinos. The obtained neutrino mixing parameters and neutrino mass squared splittings are compatible with the neutrino oscillation experimental data, for both normal and inverted hierarchies. The model predicts CP conservation in neutrino oscillations.

  17. Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background

    E-Print Network [OSTI]

    Fuller, George M; Kusenko, Alexander

    2011-01-01T23:59:59.000Z

    We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the early universe with temperatures T > 1 GeV, but in a range to give decay lifetimes from seconds to minutes. Such neutrinos would decouple early, with relic densities comparable to those of photons, but decay out of equilibrium, with consequent prodigious entropy generation prior to, or during, Big Bang Nucleosynthesis (BBN). Most of the ranges of sterile neutrino rest mass and lifetime considered are at odds with Cosmic Microwave Background (CMB) limits on the relativistic particle contribution to energy density (e.g., as parameterized by N_eff). However, some sterile neutrino parameters can lead to an acceptable N_eff. These parameter ranges are accompanie...

  18. The Lepton Sector of a Fourth Generation

    E-Print Network [OSTI]

    Gustavo Burdman; Leandro Da Rold; Ricardo D. Matheus

    2010-05-10T23:59:59.000Z

    In extensions of the standard model with a heavy fourth generation one important question is what makes the fourth-generation lepton sector, particularly the neutrinos, so different from the lighter three generations. We study this question in the context of models of electroweak symmetry breaking in warped extra dimensions, where the flavor hierarchy is generated by the localization of the zero-mode fermions in the extra dimension. In this setup the Higgs sector is localized near the infrared brane, whereas the Majorana mass term is localized at the ultraviolet brane. As a result, light neutrinos are almost entirely Majorana particles, whereas the fourth generation neutrino is mostly a Dirac fermion. We show that it is possible to obtain heavy fourth-generation leptons in regions of parameter space where the light neutrino masses and mixings are compatible with observation. We study the impact of these bounds, as well as the ones from lepton flavor violation, on the phenomenology of these models.

  19. Charged Higgs boson effects in the production and decay of a heavy Majorana neutrino at the CERN LHC

    SciTech Connect (OSTI)

    Bar-Shalom, Shaouly [Physics Department, Technion-Institute of Technology, Haifa 32000 (Israel); Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Eilam, Gad [Physics Department, Technion-Institute of Technology, Haifa 32000 (Israel); Han Tao [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); KITP, University of California, Santa Barbara, CA 93107 (United States); Soni, Amarjit [Theory Group, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2008-06-01T23:59:59.000Z

    We consider a new interaction between a heavy Majorana neutrino (N) and a charged Higgs boson (H{sup {+-}}), and show that it can have drastic implications on lepton-number-violating (LNV) signal of same-sign dileptons at the CERN LHC. The LNV signal of heavy Majorana neutrinos previously considered at the LHC, pp{yields}l{sup +}N{yields}l{sup +}l{sup +}W{sup -}, may be overwhelmed by pp{yields}l{sup +}N{yields}l{sup +}l{sup +}H{sup -}. With the subsequent decays H{sup -}{yields}tb or H{sup -}{yields}W{sup -}H{sup 0}, the heavy Majorana neutrino production leads to the spectacular events of l{sup +}l{sup +}bb+2 jets. We also explore the case m{sub N}

  20. A new map of neutrino cosmology - revised bounds on the number of neutrino species and the cosmological lepton asymmetry from WMAP data

    E-Print Network [OSTI]

    Hannestad, S

    2003-01-01T23:59:59.000Z

    We have performed a thorough analysis of the constraints which can be put on neutrino parameters from cosmological observations, most notably those from the WMAP satellite and the 2dF galaxy survey. In terms of the relativistic energy density in neutrinos or other weakly interacting species we find, in units of equivalent number of neutrino species, N_nu, that N_nu = 2.1+1.6-1.8 (95% conf.). This limit on relativistic energy density can be translated into a bound on the neutrino lepton asymmetry of |eta| 5% conf), assuming that the asymmetry is entirely in one flavour. When BBN constraints are added, the bound on N_nu is 2.5 +- 0.5 (95% conf), suggesting that N_nu could possibly be lower than the standard model value of 3. this can for instance be the case in models with very low reheating temperature and incomplete neutrino thermalization.

  1. Neutrino Mass, Sneutrino Dark Matter and Signals of Lepton Flavor Violation in the MRSSM

    E-Print Network [OSTI]

    Kumar, Abhishek; Weiner, Neal

    2009-01-01T23:59:59.000Z

    We study the phenomenology of mixed-sneutrino dark matter in the Minimal R-Symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa couplings singles out sneutrino A-terms as the only ones not automatically forbidden by R-symmetry. We perform a study of randomly generated sneutrino mass matrices and find that (i) the measured value of $\\Omega_{DM}$ is well within the range of typical values obtained for the relic abundance of the lightest sneutrino, (ii) with small lepton-number-violating mass terms $m_{nn}^{2} {\\tilde n} {\\tilde n}$ for the right-handed sneutrinos, random matrices satisfying the $\\Omega_{DM}$ constraint have a decent probability of satisfying direct detection constraints, and much of the remaining parameter space will be probed by upcoming experiments, (iii) the $m_{nn}^{2} {\\tilde n} {\\tilde n}$ terms radiatively generate appropriately small Majorana neutrino masses, with neutrino oscillation data favo...

  2. Aspects of Neutrino Masses and Lepton-Number Violation in the light of the Super-Kamiokande data

    E-Print Network [OSTI]

    Smaragda Lola

    1999-03-01T23:59:59.000Z

    We discuss aspects of neutrino masses and lepton-number violation, in the light of the observations of Super-Kamiokande. As a first step, we use the data from various experiments, in order to obtain a phenomenological understanding of neutrino mass textures. We then investigate how the required patterns of neutrino masses and mixings are related to the flavour structure of the underlying theory. In supersymmetric extensions of the Standard Model, renormalisation group effects can have important implications: for small tanb, bottom-tau unification indicates the presence of significant muon-tau flavour mixing. The evolution of the neutrino mixing may be described by simple semi-analytic expressions, which confirm that, for large tanb, very small mixing at the GUT scale may be amplified to maximal mixing at low energies, and vice versa. Passing to specific models, we first discuss the predictions for neutrino masses in different GUT models (including superstring-embedded solutions). Imposing the requirement for successful leptogenesis may give additional constraints on the generic structure of the neutrino mass textures. Finally, we discuss direct ways to look for lepton-number violation in ultra-high energy neutrino interactions.

  3. On leptonic decay of a heavy quarkonium with a Higgs-boson emission

    E-Print Network [OSTI]

    G. A. Kozlov

    2005-06-27T23:59:59.000Z

    A leptonic $(\\bar l l)$ decay of a heavy quark-antiquark bound state $T(\\bar QQ)$ with a Higgs-boson $H$ emission is investigated. The applying of the well-known low-energy theorem to meson-Higgs coupling allows one to estimate the probability of the decay $T(\\bar QQ)\\to \\bar ll H$. The only a simple version of the Standard Model extension containing two-Higgs doublet is considered.

  4. Heavy Quark and Neutrino Physics Final Report 2011 – 2014

    SciTech Connect (OSTI)

    Horton-Smith, Glenn A. [Kansas State University] (ORCID:0000000196779167); Bolton, Timothy [Kansas State University; Ivanov, Andrew [Kansas State University; Maravin, Yurii [Kansas State University; Ratra, Bharat [Kansas State University

    2014-07-21T23:59:59.000Z

    This final closeout report covers research supported by the ``Heavy Quark and Neutrino Physics'' grant at Kansas State University during the grant's last renewal period, November 1, 2011, through April 30, 2014. The report begins with an overview of the group, its goals and activities, and personnel. Then summaries are given of achievements in each of the three frontiers: Energy Frontier research in the D0 and CMS experiments; Intensity Frontier research in the Double Chooz and ArgoNeuT experiments as well as research and development for MicroBooNE and LBNE; and Cosmic Frontier and Theoretical research. The report concludes with a list of publications supported by this grant in which our group made a significant contribution during the reporting period, followed by a list of students partially or fully supported by the grant who were awarded a PhD during this period.

  5. Flavor symmetry L{sub e}-L{sub {mu}}-L{sub {tau}}, atmospheric neutrino mixing, and CP violation in the lepton sector

    SciTech Connect (OSTI)

    Petcov, S.T.; Rodejohann, W. [Scuola Internazionale Superiore di Studi Avanzati, Via Beirut 2-4, I-34014 Trieste, Italy and Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34014 Trieste (Italy)

    2005-04-01T23:59:59.000Z

    The Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing matrix is given, in general, by the product of two unitary matrices associated with the diagonalization of the charged lepton and neutrino mass matrices. Assuming that the active flavor neutrinos possess a Majorana mass matrix which is diagonalized by a bimaximal mixing matrix, we give the allowed forms of the charged lepton mixing matrix and the corresponding implied forms of the charged lepton mass matrix. We then assume that the origin of bimaximal mixing is a weakly broken flavor symmetry corresponding to the conservation of the nonstandard lepton charge L{sup '}=L{sub e}-L{sub {mu}}-L{sub {tau}}. The latter does not predict, in general, the atmospheric neutrino mixing to be maximal. We study the impact of this fact on the allowed forms of the charged lepton mixing matrix and on the neutrino mixing observables, analyzing the case of CP violation in detail. When compared with the case of exact bimaximal mixing, the deviations from zero U{sub e3} and from maximal atmospheric neutrino mixing are typically more sizable if one assumes just L{sup '} conservation. In fact, |U{sub e3}|{sup 2} can be as small as 0.007 and atmospheric neutrino mixing can take any value inside its currently allowed range. We discuss under which conditions the atmospheric neutrino mixing angle is larger or smaller than {pi}/4. We present also a simple seesaw realization of the implied light neutrino Majorana mass matrix and consider leptogenesis in this scenario.

  6. Neutrino Masses via a Seesaw with Heavy Majorana and Dirac Neutrino Mass Matrices from Discrete Subgroup $\\Delta (27)$ of $SU(3)$

    E-Print Network [OSTI]

    Damanik, Asan

    2010-01-01T23:59:59.000Z

    Neutrino mass matrix via a seesaw mechanism is constructed by assuming that the underlying symmetry of both heavy Majorana and Dirac mass matrices is the discrete subgroup $\\Delta(27)$ symmetry of $SU(3)$. Using the experimental data of neutrino oscillation, the neutrino mass matrix exhibits maximal $\

  7. Baryogenesis via leptogenesis from quark-lepton symmetry and a compact heavy N{sub R} spectrum

    SciTech Connect (OSTI)

    Buccella, F.; Falcone, D.; Oliver, L. [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Napoli (Italy); INFN, Sezione di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Napoli (Italy); Laboratoire de Physique Theorique Universite de Paris XI, Batiment 210, 91405 Orsay Cedex (France)

    2011-05-01T23:59:59.000Z

    By demanding a compact spectrum for the right-handed neutrinos and an approximate quark-lepton symmetry inspired from SO(10) gauge unification (assuming a Dirac neutrino mass matrix close to the up quark mass matrix), we construct a fine-tuning scenario for baryogenesis via leptogenesis. We find two solutions with a normal hierarchy, with the lightest neutrino mass m{sub 1} different from zero, providing an absolute scale for the spectrum. In the approximations of the model, there are three independent CP phases: {delta}{sub L} (that we take of the order of the quark Kobayashi-Maskawa phase) and the two light neutrino Majorana phases {alpha} and {beta}. A main conclusion is that, although this general scheme is rather flexible, in some regions of parameter space we find that the necessary baryogenesis with its sign is given in terms of the {delta}{sub L} phase alone. The light Majorana phases can also be computed, and they turn out to be close to {pi}/2 or very small. Moreover, SO(10) breaks down to the Pati-Salam group SU(4)xSU(2)xSU(2) at the expected natural intermediate scale of about 10{sup 10}-10{sup 11} GeV. A prediction is made for the effective mass in ({beta}{beta}){sub 0{nu}} decay, the {nu}{sub e} mass, and the sum of all light neutrino masses.

  8. Heavy Sterile Neutrinos and Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    Manimala Mitra; Goran Senjanovic; Francesco Vissani

    2012-05-17T23:59:59.000Z

    Sterile neutrinos of mass up to a few tens of TeV can saturate the present experimental bound of neutrinoless double beta decay process. Due to the updated nuclear matrix elements, the bound on mass and mixing angle is now improved by one order of magnitude. We have performed a detailed analysis of neutrinoless double beta decay for the minimal Type I seesaw scenario. We have shown that in spite of the naive expectation that the light neutrinos give the dominant contribution, sterile neutrinos can saturate the present experimental bound of neutrinoless double beta decay process. However, in order to be consistent with radiative stability of light neutrino masses, the mass scale of sterile neutrinos should be less than 10 GeV.

  9. SU(3) Gauge Family Symmetry and Prediction for the Lepton-Flavor Mixing and Neutrino Masses with Maximal Spontaneous CP Violation

    E-Print Network [OSTI]

    Yue-Liang Wu

    2012-07-12T23:59:59.000Z

    A model for the lepton-flavor mixing and CP violation is proposed based on the SU$_F$(3) gauge family symmetry and the Majorana feature of neutrinos. A consistent prediction for the lepton-flavor mixing and masses is shown to be resulted from the appropriate vacuum structure of SU$_F$(3) gauge symmetry breaking. By choosing the SU$_F$(3) gauge fixing condition to possess a residual $Z_2$ symmetry and requiring the vacuum structure of spontaneous symmetry breaking to have approximate global U(1) family symmetries, we obtain naturally the tri-bimaximal mixing matrix and largely degenerate neutrino masses in the neutrino sector and the small mixing matrix in the charged-lepton sector. With a simple ansatz that all the smallness due to the approximate global U(1) family symmetries is characterized by a single Wolfenstein parameter $\\lambda \\simeq 0.22$, and the charged-lepton mixing matrix has a similar hierarchy structure as the CKM quark mixing matrix, we arrive at a consistent prediction for the MNSP lepton-flavor mixing with a maximal spontaneous CP violation: $\\delta =\\pi/2$, $\\sin^2\\theta_{13} \\simeq 1/2\\lambda^2 \\simeq 0.024$ ($\\sin^22\\theta_{13} \\simeq 0.094$), $\\sin^2\\theta_{12} \\simeq 1/3{3}(1 - 2\\lambda^3) \\simeq 0.326$ and $\\sin^2\\theta_{23} \\simeq 1/2(1 - \\lambda^2) \\simeq 0.48$, which agree well with the current experimental data. The CP-violating Jarlskog-invariant is obtained to be $J_{CP} \\simeq 1/6\\lambda(1-\\lambda^2/2-\\lambda^3)\\sin\\delta \\simeq 0.035$, which is detectable in next generation neutrino experiment. The largely degenerate neutrino masses with the normal hierarchy and inverse hierarchy are discussed and found be at the order $m_{\

  10. Phenomenology of the minimal B-L extension of the standard model: Z{sup '} and neutrinos

    SciTech Connect (OSTI)

    Basso, Lorenzo; Belyaev, Alexander; Moretti, Stefano [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); Shepherd-Themistocleous, Claire H. [Particle Physics Department, Rutherford Appleton Laboratory, Chilton Didcot, Oxon OX11 0QX (United Kingdom)

    2009-09-01T23:59:59.000Z

    We present the Large Hadron Collider (LHC) discovery potential in the Z{sup '} and heavy neutrino sectors of a U(1){sub B-L} enlarged standard model also encompassing 3 heavy Majorana neutrinos. This model exhibits novel signatures at the LHC, the most interesting arising from a Z{sup '} decay chain involving heavy neutrinos, eventually decaying into leptons and jets. In particular, this signature allows one to measure the Z{sup '} and heavy neutrino masses involved. In addition, over a large region of the parameter space, the heavy neutrinos are rather long-lived particles producing distinctive displaced vertices that can be seen in the detectors. Lastly, the simultaneous measurement of both the heavy neutrino mass and decay length enables an estimate of the absolute mass of the parent light neutrino.

  11. On the description of non-unitary neutrino mixing

    E-Print Network [OSTI]

    F. J. Escrihuela; D. V. Forero; O. G. Miranda; M. Tortola; J. W. F. Valle

    2015-04-13T23:59:59.000Z

    Neutrino oscillations are well established and the relevant parameters determined with good precision, except for the CP phase, in terms of a unitary lepton mixing matrix. Seesaw extensions of the Standard Model predict unitarity deviations due to the admixture of heavy isosinglet neutrinos. We provide a complete description of the unitarity and universality deviations in the light neutrino sector. Neutrino oscillation experiments involving electron or muon neutrinos and anti-neutrinos are fully described in terms of just three new real parameters and a new CP phase, in addition to the ones describing oscillations with unitary mixing. Using this formalism we describe the implications of non-unitarity for neutrino oscillations and summarize the model-independent constraints on heavy neutrino couplings that arise from current experiments.

  12. Lepton sector of a fourth generation

    SciTech Connect (OSTI)

    Burdman, G. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil); Da Rold, L. [Centro Atomico Bariloche, Bariloche (Argentina); Matheus, R. D. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)

    2010-09-01T23:59:59.000Z

    In extensions of the standard model with a heavy fourth generation, one important question is what makes the fourth-generation lepton sector, particularly the neutrinos, so different from the lighter three generations. We study this question in the context of models of electroweak symmetry breaking in warped extra dimensions, where the flavor hierarchy is generated by choosing the localization of the zero-mode fermions in the extra dimension. In this setup the Higgs sector is localized near the infrared brane, whereas the Majorana mass term is localized at the ultraviolet brane. As a result, light neutrinos are almost entirely Majorana particles, whereas the fourth-generation neutrino is mostly a Dirac fermion. We show that it is possible to obtain heavy fourth-generation leptons in regions of parameter space where the light neutrino masses and mixings are compatible with observation. We study the impact of these bounds, as well as the ones from lepton flavor violation, on the phenomenology of these models.

  13. Lepton flavor violation as a probe of quark-lepton unification

    SciTech Connect (OSTI)

    Cheung, Kingman; Kang, Sin Kyu; Kim, C.S.; Lee, Jake [Department of Physics, Tsing Hua Univeristy, Hsinchu, Taiwan (China); School of Physics, Seoul National University, Seoul 151-741 (Korea, Republic of); Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2005-08-01T23:59:59.000Z

    The recent measurements of the solar neutrino mixing angle {theta}{sub sol} and the Cabibbo mixing angle {theta}{sub C} reveal a surprising relation, {theta}{sub sol}+{theta}{sub C}{approx_equal}({pi}/4), which has been interpreted as an evidence for quark-lepton unification. We show in realizations of quark-lepton unification that the PMNS mixing matrix can be decomposed into a CKM-like matrix and maximal mixing matrices. We explore a possibility to probe such implications by considering the relative sizes of branching ratios for the lepton flavor violating radiative decay processes, l{sub i}{yields}l{sub j}{gamma}, in the context of the supersymmetric standard model with heavy right-handed Majorana neutrinos.

  14. Numerical Implementation of lepton-nucleus interactions and its effect on neutrino oscillation analysis

    E-Print Network [OSTI]

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

    2014-10-13T23:59:59.000Z

    We discuss the implementation of the nuclear model based on realistic nuclear spectral functions in the GENIE neutrino interaction generator. Besides improving on the Fermi gas description of the nuclear ground state, our scheme involves a new prescription for $Q^2$ selection, meant to efficiently enforce energy momentum conservation. The results of our simulations, validated through comparison to electron scattering data, have been obtained for a variety of target nuclei, ranging from carbon to argon, and cover the kinematical region in which quasi elastic scattering is the dominant reaction mechanism. We also analyse the influence of the adopted nuclear model on the determination of neutrino oscillation parameters.

  15. Selected Topics in Majorana Neutrino Physics

    E-Print Network [OSTI]

    Maiani, Luciano

    2014-01-01T23:59:59.000Z

    Starting from the original Majorana's article of 1937, the see-saw mechanism is illustrated, first for one and later for three neutrino generations, and neutrinoless double beta decay is considered. Neutrino mixing and oscillations in three flavors are described. The Yukawa couplings to the Higgs field of quarks and leptons are considered, their transformation properties under the corresponding flavor groups are spelled and the principle of Minimal Flavor Violation is illustrated, in connection with possible new physics beyond the Standard Theory. The idea that the Yukawa couplings may be the vacuum expectation value of some new fields is introduced and natural extrema of potentials which are invariant under quark and lepton flavor groups are characterized. A recent result indicating large mixing of almost degenerate neutrinos is derived from the heavy lepton invariance under flavor ${\\cal O}(3)$.

  16. The anomalous lepton magnetic moment, LFV decays and the fourth generation

    E-Print Network [OSTI]

    W. J. Huo; T. F. Feng

    2003-01-20T23:59:59.000Z

    We investigate the lepton flavor violation (LFV) decays, $\\tau\\to l\\gamma$ ($l=\\mu, e$) and $\\mu\\to e\\gamma$, and the newly observed muon $g-2$ anomaly in the framwork of a squential fourth generation model with a heavy fourth neutrino, $\

  17. Parity violating radiative emission of neutrino pair in heavy alkaline earth atoms of even isotopes

    E-Print Network [OSTI]

    M. Yoshimura; N. Sasao; S. Uetake

    2014-03-26T23:59:59.000Z

    Metastable excited states ${}^3P_2, {}^3P_0$ of heavy alkaline earth atoms of even isotopes are studied for parity violating (PV) effects in radiative emission of neutrino pair (RENP). PV terms arise from interference between two diagrams containing neutrino pair emission of valence spin current and nuclear electroweak charge density proportional to the number of neutrons in nucleus. This mechanism gives large PV effects, since it does not suffer from the suppression of 1/(electron mass) usually present for non-relativistic atomic electrons. A controllable magnetic field is crucial to identify RENP process by measuring PV observables. Results of PV asymmetries under the magnetic field reversal and the photon circular polarization reversal are presented for an example of Yb atom.

  18. Search for heavy neutrinos and W bosons with right-handed couplings in proton-proton collisions at sqrt(s) = 8 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2014-12-01T23:59:59.000Z

    A search for heavy, right-handed neutrinos, N[l] (l = e, mu), and right-handed WR bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton-proton collisions at a center-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 inverse femtobarns. For models with strict left-right symmetry, and assuming only one N[l] flavor contributes significantly to the WR decay width, the region in the two-dimensional (M[WR], M[N]) mass plane excluded at a 95% confidence level extends to approximately M[WR] = 3.0 TeV and covers a large range of neutrino masses below the WR boson mass, depending on the value of M[WR]. This search significantly extends the (M[WR], M[N]) exclusion region beyond previous results.

  19. Neutrino Yukawa textures within type-I see-saw

    E-Print Network [OSTI]

    Biswajit Adhikary; Probir Roy

    2012-11-02T23:59:59.000Z

    The arbitrariness of Yukawa couplings can be reduced by the imposition of some flavor symmetries and/or by the realization of texture zeros. We review neutrino Yukawa textures with zeros within the framework of the type-I seesaw with three heavy right chiral neutrinos and in the basis where the latter and the charged leptons are mass diagonal. An assumed non-vanishing mass of every ultralight neutrino and the observed non-decoupling of any neutrino generation allow a maximum of four zeros in the Yukawa coupling matrix $Y_\

  20. Lepton number violation and W ? chiral couplings at the LHC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Han, Tao; Lewis, Ian; Ruiz, Richard; Si, Zong-guo

    2013-02-01T23:59:59.000Z

    We study the observability for a heavy Majorana neutrino N along with a new charged gauge boson W' at the LHC. We emphasize the complementarity of these two particles in their production and decay to unambiguously determine their properties. We show that the Majorana nature of N can be verified by the lepton number violating like-sign dilepton process, and by polar and azimuthal angular distributions. The chirality of the W' coupling to leptons and to quarks can be determined by a polar angle distribution in the reconstructed frame and an azimuthal angle distribution.

  1. Leptogenesis in a seesaw model with Fritzsch-type lepton mass matrices

    SciTech Connect (OSTI)

    Ahn, Y. H.; Kim, C. S.; Lee, Jake [Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Kang, Sin Kyu [School of Liberal Arts, Seoul National University of Technology, Seoul 139-743 (Korea, Republic of)

    2008-04-01T23:59:59.000Z

    We investigate how the baryon asymmetry of our Universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch-type lepton mass matrices proposed by Fukugita et al. We study the cases with CP-violating phases in charged-lepton Yukawa matrix, however, with and without Dirac neutrino Yukawa phases. We consider both flavor-independent and flavor-dependent leptogenesis, and demonstrate how they lead to different amounts of lepton asymmetries in detail. In particular, it is shown that flavor-dependent leptogenesis in this model can be achieved only for very tiny or zero values of CP phases in Dirac neutrino Yukawa matrix at the grand unified theory scale. In addition to the CP phases, for successful leptogenesis in the model it is required that the degeneracy of the heavy Majorana neutrino mass spectrum should be broken and we also show that the breakdown of the degeneracy can be radiatively induced.

  2. Bounds on neutrino masses from leptogenesis in type-II seesaw models

    SciTech Connect (OSTI)

    Sahu, Narendra; Sankar, S. Uma [Department of Physics, Indian Institute of Technology, Bombay, Mumbai 400076 (India)

    2005-01-01T23:59:59.000Z

    The presence of the triplet {delta}{sub L} in left-right symmetric theories leads to type-II seesaw mechanism for the neutrino masses. In these models, assuming a normal mass hierarchy for the heavy Majorana neutrinos, we derive a lower bound on the mass of the lightest of heavy Majorana neutrinos from the leptogenesis constraint. From this bound we establish a consistent picture for the hierarchy of heavy Majorana neutrinos in a class of left-right symmetric models in which we identify the neutrino Dirac mass matrix with that of Fritzsch type charged lepton mass matrix. It is shown that these values are compatible with the current neutrino oscillation data.

  3. REVIEW OF HEAVY LEPTON PRODUCTION IN e+e- ANNIHILATION* Martin L. Per1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah47,193.70COMMUNITYResponses:December 11, 2014WD2 MAY2REVIEW OF HEAVY

  4. 8Li electron spectrum versus 8B neutrino spectrum Implications for measuring solar neutrinos with a heavy water detector

    E-Print Network [OSTI]

    Jonkmans, G; Sur, B

    1998-01-01T23:59:59.000Z

    The sensitivity of the Sudbury Neutrino Observatory (SNO) to measure the shape of the recoil electron spectrum in the charged-current reaction of $^{8}$B solar neutrinos interacting with deuterium can be improved if the results of a $^{8}$Li beta-decay calibration experiment are included in the test. We calculate an improvement in sensitivity, under certain idealistic assumptions, of about a factor of 2, sufficient to resolve different neutrino-oscillation solutions to the solar-neutrino problem. We further examine the role of recoil and radiative corrections on both the $^{8}$B neutrino spectrum and the $^{8}$Li electron spectrum and conclude that the influence of these effects on the ratio of the two spectra as measured by SNO is very small.

  5. Lepton Number Violation within the Conformal Inverse Seesaw

    E-Print Network [OSTI]

    Humbert, Pascal; Patra, Sudhanwa; Smirnov, Juri

    2015-01-01T23:59:59.000Z

    We present a novel framework within the conformal inverse seesaw scheme allowing large lepton number violation while the neutrino mass formula is still governed by the low-scale inverse seesaw mechanism. This model includes new contributions to rare low-energy lepton number violating processes like neutrinoless double beta decay. We find that the lifetime for this rare process due to heavy sterile neutrinos can saturate current experimental limits. The characteristic collider signature of the present conformal inverse seesaw scheme includes, same-sign dilepton plus two jets and same-sign dilepton plus four jets. Finally, we comment on the testability of the model at the Large Hadron Collider since there are new scalars, new fermions and an extra neutral gauge boson with masses around few 100 GeV to few TeV.

  6. Leptogenesis within a generalized quark-lepton symmetry

    SciTech Connect (OSTI)

    Buccella, F.; Falcone, D.; Oliver, L. [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy) and INFN, Sezione di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy); Laboratoire de Physique Theorique, Universite de Paris XI, Batiment 210, Orsay Cedex (France)

    2008-02-01T23:59:59.000Z

    We reexamine the question of baryogenesis via leptogenesis in schemes of the seesaw mechanism with quark-lepton symmetry. Within the phenomenological approach of textures, we propose to relax this strict symmetry and propose weaker conditions, namely, models of the neutrino Dirac mass matrix M{sub D} which have the same hierarchy as the matrix elements of M{sub u}. We call this guideline generalized hierarchical quark-lepton symmetry. We consider in detail particular cases in which the moduli of the matrix elements of M{sub D} are equal to those of M{sub u}. We try for the heavy Majorana mass matrix diagonal and off-diagonal forms. We find that an ansatz for M{sub D} preserving the hierarchy, together with an off-diagonal model for the heavy Majorana neutrino mass, is consistent with neutrino masses, neutrino mixing, and baryogenesis via leptogenesis for an intermediate mass scale m{sub R}{approx}10{sup 12} GeV. The preservation of the hierarchical structure could come from a possible symmetry scheme.

  7. Left-right models with light neutrino mass prediction and dominant neutrinoless double beta decay rate

    E-Print Network [OSTI]

    M. K. Parida; Sudhanwa Patra

    2013-01-14T23:59:59.000Z

    In TeV scale left-right symmetric models, new dominant predictions to neutrinoless double beta decay and light neutrino masses are in mutual contradiction because of large contribution to the latter through popular seesaw mechanisms. We show that in a class of left-right models with high-scale parity restoration, these results coexist without any contravention with neutrino oscillation data and the relevant formula for light neutrino masses is obtained via gauged inverse seesaw mechanism. The most dominant contribution to the double beta decay is shown to be via $W^-_L- W^-_R$ mediation involving both light and heavy neutrino exchanges, and the model predictions are found to discriminate whether the Dirac neutrino mass is of quark-lepton symmetric origin or without it. We also discuss associated lepton flavor violating decays.

  8. Probing the coupling of heavy dark matter to nucleons by detecting neutrino signature from the Earth core

    E-Print Network [OSTI]

    Guey-Lin Lin; Yen-Hsun Lin

    2014-04-02T23:59:59.000Z

    We argue that the detection of neutrino signature from the Earth core is an ideal approach for probing the coupling of heavy dark matter ($m_{\\chi}>10^{4}$ GeV) to nucleons. We first note that direct searches for dark matter (DM) in such a mass range do not provide stringent constraints. Furthermore the energies of neutrinos arising from DM annihilations inside the Sun cannot exceed a few TeV at the Sun surface due to the attenuation effect. Therefore the sensitivity to the heavy DM coupling is lost. Finally, the detection of neutrino signature from galactic halo can only probe DM annihilation cross sections. After presenting the rationale of our studies, we discuss the event rates in IceCube and KM3NeT arising from the neutrino flux produced by annihilations of Earth-captured DM heavier than $10^{4}$ GeV. The IceCube and KM3NeT sensitivities to spin independent DM-proton scattering cross section $\\sigma_{\\chi p}$ and isospin violation effect in this mass range are presented. The implications of our results are also discussed.

  9. Preon Trinity - a new model of leptons and quarks

    E-Print Network [OSTI]

    Jean-Jacques Dugne; Sverker Fredriksson; Johan Hansson; Enrico Predazzi

    1999-10-12T23:59:59.000Z

    A new model for the substructure of quarks, leptons and weak gauge bosons is discussed. It is based on three fundamental and absolutely stable spin-1/2 preons. Its preon flavour SU(3) symmetry leads to a prediction of nine quarks, nine leptons and nine heavy vector bosons. One of the quarks has charge $-4e/3$, and is speculated to be the top quark (whose charge has not been measured). The flavour symmetry leads to three conserved lepton numbers in all known weak processes, except for some neutrinos, which might either oscillate or decay. There is also a (Cabibbo) mixing of the $d$ and $s$ quarks due to an internal preon-antipreon annihilation channel. An identical channel exists inside the composite $Z^0$, leading to a relation between the Cabibbo and Weinberg mixing angles.

  10. Symmetrical parametrizations of the lepton mixing matrix

    SciTech Connect (OSTI)

    Rodejohann, W. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apt 22085, E-46071 Valencia (Spain)

    2011-10-01T23:59:59.000Z

    Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.

  11. Baryogenesis via neutrino oscillations

    E-Print Network [OSTI]

    E. Kh. Akhmedov; V. A. Rubakov; A. Yu. Smirnov

    1998-07-29T23:59:59.000Z

    We propose a new mechanism of leptogenesis in which the asymmetries in lepton numbers are produced through the CP-violating oscillations of ``sterile'' (electroweak singlet) neutrinos. The asymmetry is communicated from singlet neutrinos to ordinary leptons through their Yukawa couplings. The lepton asymmetry is then reprocessed into baryon asymmetry by electroweak sphalerons. We show that the observed value of baryon asymmetry can be generated in this way, and the masses of ordinary neutrinos induced by the seesaw mechanism are in the astrophysically and cosmologically interesting range. Except for singlet neutrinos, no physics beyond the Standard Model is required.

  12. Neutrinos

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3, Issue 30NeutrinoNeutrinos from the

  13. Neutrinoless double beta decay and pseudo-Dirac neutrino mass predictions through inverse seesaw mechanism

    E-Print Network [OSTI]

    Ram Lal Awasthi; M. K. Parida; Sudhanwa Patra

    2013-01-21T23:59:59.000Z

    In the inverse seesaw extension of the standard model, supersymmetric or non-supersymmetric, while the light left-handed neutrinos are Majorana, the heavy right-handed neutrinos are pseudo-Dirac fermions. We show how one of these latter category of particles can contribute quite significantly to neutrinoless double beta decay. The neutrino virtuality momentum is found to play a crucial role in the non-standard contributions leading to the prediction of the pseudo-Dirac fermion mass in the range of $120\\, {MeV}-500\\, {MeV}$. When the Dirac neutrino mass matrix in the inverse seesaw formula is similar to the up-quark mass matrix, characteristic of high scale quark-lepton symmetric origin, the predicted branching ratios for lepton flavor violating decays are also found to be closer to the accessible range of ongoing experiments.

  14. Neutrinos in Nuclear Physics

    E-Print Network [OSTI]

    R. D. McKeown

    2014-12-03T23:59:59.000Z

    Since the discovery of nuclear beta decay, nuclear physicists have studied the weak interaction and the nature of neutrinos. Many recent and current experiments have been focused on the elucidation of neutrino oscillations and neutrino mass. The quest for the absolute value of neutrino mass continues with higher precision studies of the tritium beta decay spectrum near the endpoint. Neutrino oscillations are studied through measurements of reactor neutrinos as a function of baseline and energy. And experiments searching for neutrinoless double beta decay seek to discover violation of lepton number and establish the Majorana nature of neutrino masses.

  15. Neutrinos in Nuclear Physics

    E-Print Network [OSTI]

    McKeown, R D

    2014-01-01T23:59:59.000Z

    Since the discovery of nuclear beta decay, nuclear physicists have studied the weak interaction and the nature of neutrinos. Many recent and current experiments have been focused on the elucidation of neutrino oscillations and neutrino mass. The quest for the absolute value of neutrino mass continues with higher precision studies of the tritium beta decay spectrum near the endpoint. Neutrino oscillations are studied through measurements of reactor neutrinos as a function of baseline and energy. And experiments searching for neutrinoless double beta decay seek to discover violation of lepton number and establish the Majorana nature of neutrino masses.

  16. Texture 4 zero Fritzsch-like lepton mass matrices

    E-Print Network [OSTI]

    Gulsheen Ahuja; Sanjeev Kumar; Monika Randhawa; Manmohan Gupta; S. Dev

    2008-02-20T23:59:59.000Z

    For Majorana or Dirac neutrinos, using Fritzsch-like texture 4 zero mass matrices with parallel texture structures for the charged leptons and the Dirac neutrino mass matrix (M_{\

  17. New textures for the lepton mass matrices

    E-Print Network [OSTI]

    P. M. Ferreira; L. Lavoura

    2014-12-02T23:59:59.000Z

    We study predictive textures for the lepton mass matrices in which the charged-lepton mass matrix has either four or five zero matrix elements while the neutrino Majorana mass matrix has, respectively, either four or three zero matrix elements. We find that all the viable textures of these two kinds share many predictions: the neutrino mass spectrum is inverted, the sum of the light-neutrino masses is close to 0.1 eV, the Dirac phase $\\delta$ in the lepton mixing matrix is close to either $0$ or $\\pi$, and the mass term responsible for neutrinoless double-beta decay lies in between 12 and 22 meV.

  18. Charged- and neutral-current solar-neutrino cross sections for heavy-water Cherenkov detectors

    SciTech Connect (OSTI)

    Ying, S.; Haxton, W.C.; Henley, E.M. (Department of Physics, FM-15, and National Institute for Nuclear Theory, HN-12, University of Washington, Seattle, Washington 98195 (United States))

    1992-04-01T23:59:59.000Z

    Charged- and neutral-current neutrino cross sections for deuterium have been calculated for the Bonn, Paris, and Hamada-Johnson potentials in order to estimate event rates (and their uncertainties) for solar and supernova neutrino detection in the Sudbury Solar Neutrino Observatory. Tests of the wave functions are provided by calculations of the {ital j}=1/2 hyperfine-state muon capture rate and of the total cross section for absorbing {nu}{sub {ital e}s} from stopped muon decay. Detailed tables of the Paris potential results are given, and comparisons are made to the work of Doi and Kubodera.

  19. Neutrinoless double beta decay and neutrino physics

    E-Print Network [OSTI]

    Werner Rodejohann

    2012-08-20T23:59:59.000Z

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

  20. Neutrino

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3, Issue 30Neutrino cross section

  1. Oscillations of Mossbauer neutrinos

    E-Print Network [OSTI]

    Evgeny Kh. Akhmedov; Joachim Kopp; Manfred Lindner

    2008-05-02T23:59:59.000Z

    We calculate the probability of recoilless emission and detection of neutrinos (Mossbauer effect with neutrinos) taking into account the boundedness of the parent and daughter nuclei in the neutrino source and detector as well as the leptonic mixing. We show that, in spite of their near monochromaticity, the recoillessly emitted and captured neutrinos oscillate. After a qualitative discussion of this issue, we corroborate and extend our results by computing the combined rate of $\\bar{\

  2. Neutrino Masses

    E-Print Network [OSTI]

    Christian Weinheimer; Kai Zuber

    2013-09-04T23:59:59.000Z

    The various experiments on neutrino oscillation evidenced that neutrinos have indeed non-zero masses but cannot tell us the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and the structure formation of the universe as well as for nuclear and particle physics beyond the present Standard Model. Complementary to deducing constraints on the sum of all neutrino masses from cosmological observations two different methods to determine the neutrino mass scale in the laboratory are pursued: the search for neutrinoless double $\\beta$-decay and the direct neutrino mass search by investigating single $\\beta$-decays or electron captures. The former method is not only sensitive to neutrino masses but also probes the Majorana character of neutrinos and thus lepton number violation with high sensitivity. Currently quite a few experiments with different techniques are being constructed, commissioned or are even running, which aim for a sensitivity on the neutrino mass of {\\cal O}(100) meV. The principle methods and these experiments will be discussed in this short review.

  3. On quark-lepton complementarity

    E-Print Network [OSTI]

    F. Gonzalez-Canales; A. Mondragon

    2006-06-16T23:59:59.000Z

    Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation theta_{sol} + theta_{C} ~ 45^{o}. This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices V_{CKM} and U_{MNSP} as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.

  4. On quark-lepton complementarity

    SciTech Connect (OSTI)

    Gonzalez Canales, F.; Mondragon, A. [Instituto de Fisica, UNAM, 04510, Mexico D.F. (Mexico)

    2006-09-25T23:59:59.000Z

    Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation {theta}{sub sol} + {theta}{sub C} {approx_equal} ({pi}/4). This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices VCKM and UMNSP as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.

  5. Upper Limits on Electric and Weak Dipole Moments of Tau-Lepton and Heavy Quarks from e+e- Annihilation

    E-Print Network [OSTI]

    A. E. Blinov; A. S. Rudenko

    2009-03-23T23:59:59.000Z

    The total cross-sections measured at LEP for e+e- annihilation into tau+tau-, c\\bar{c} and b\\bar{b} at 2E ~ 200 GeV are used to derive the upper limits 3*10^{-17}, 5*10^{-17}, 2*10^{-17} e*cm for the electric dipole moments and 4*10^{-17}, 7*10^{-17}, 2.5*10^{-17} e*cm for the weak dipole moments of the tau-lepton, c-, and b-quarks, respectively. Some of the existing limits on these moments are improved and for the b-quark the improvement is rather significant.

  6. F-theory and Neutrinos: Kaluza-Klein Dilution of Flavor Hierarchy

    SciTech Connect (OSTI)

    Seo, Jihye [Jefferson Physical Laboratory, Harvard University, Cambridge, MA 02138 (United States)

    2010-02-10T23:59:59.000Z

    We present a Majorana neutrino scenario in a F-theory SU(5) GUT model, which is recently proposed in [1]. The mass scale of the neutrinos arises from integrating out heavy Kaluza-Klein modes on the right-handed neutrinos. The participation of non-holomorphic Kaluza-Klein mode wave functions dilutes the mass hierarchy in comparison to the quark and charged lepton sectors, in agreement with experimentally measured mass splittings. The neutrinos are predicted to exhibit a 'normal' mass hierarchy, with masses (m{sub 3}, m{sub 2}, m{sub 1})approx.05x(1,alpha{sub GUT}{sup 1/2},alpha{sub GUT}) eV. The neutrino mixing matrix exhibits a mild hierarchical structure with theta{sub 13}approxalpha{sub GUT}{sup 1/2}approx0.2. We also predict mass measurements in single and double beta decay experiments.

  7. Universal Mass Texture, CP violation and Quark-Lepton Complementarity

    E-Print Network [OSTI]

    Canales, F Gonzalez; Barranco, J

    2010-01-01T23:59:59.000Z

    Recent measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggests the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We asssume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a two zeroes Fritzsch texture.

  8. Universal mass matrix for quarks and leptons and CP violation

    SciTech Connect (OSTI)

    Barranco, J.; Gonzalez Canales, F.; Mondragon, A. [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Golm (Germany); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510, Mexico D.F. (Mexico)

    2010-10-01T23:59:59.000Z

    The measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggest the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We assume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a universal form with four texture zeroes.

  9. Form invariance and symmetry in the neutrino mass matrix

    SciTech Connect (OSTI)

    Lashin, E. I. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Nasri, S.; Malkawi, E. [Department of Physics, UAE University, P.O. Box 17551, Al-Ain (United Arab Emirates); Chamoun, N. [Physics Department, HIAST, P.O. Box 31983, Damascus (Syrian Arab Republic)

    2011-01-01T23:59:59.000Z

    We present the general form of the unitary matrices keeping invariant the Majorana neutrino mass matrix of specific texture suitable for explaining oscillation data. In the case of the tri-bimaximal pattern with two degenerate masses, we give a specific realization of the underlying U(1) symmetry which can be uplifted to a symmetry in a complete theory including charged leptons. For this, we present a model with three light SM-like Higgs doublets and one heavy Higgs triplet and find that one can accommodate the hierarchy of the charged-lepton masses. The lepton mass spectrum can also be achieved in another model extending the SM with three SM-singlet scalars transforming nontrivially under the flavor symmetry. We discuss how such a model has room for generating enough baryon asymmetry through leptogenesis in the framework of type-I and -II seesaw mechanisms.

  10. Lepton number violation and W ? chiral couplings at the LHC

    SciTech Connect (OSTI)

    Han, Tao; Lewis, Ian; Ruiz, Richard; Si, Zong-guo

    2013-02-01T23:59:59.000Z

    We study the observability for a heavy Majorana neutrino N along with a new charged gauge boson W' at the LHC. We emphasize the complementarity of these two particles in their production and decay to unambiguously determine their properties. We show that the Majorana nature of N can be verified by the lepton number violating like-sign dilepton process, and by polar and azimuthal angular distributions. The chirality of the W' coupling to leptons and to quarks can be determined by a polar angle distribution in the reconstructed frame and an azimuthal angle distribution.

  11. Leptonic CP Violation from a New Perspective

    E-Print Network [OSTI]

    David Emmanuel-Costa; Nuno Rosa Agostinho; J. I. Silva-Marcos; Daniel Wegman

    2015-04-27T23:59:59.000Z

    We study leptonic CP violation from a new perspective. For Majorana neutrinos, a new parametrization for leptonic mixing of the form $V=O_{23} O_{12} K_{a}^{i}\\cdot O$ reveals interesting aspects that are less clear in the standard parametrization. We identify several important scenario-cases with mixing angles in agreement with experiment and leading to large leptonic CP violation. If neutrinos happen to be quasi-degenerate, this new parametrization might be very useful, e.g., in reducing the number of relevant parameters of models.

  12. Leptonic CP Violation from a New Perspective

    E-Print Network [OSTI]

    Emmanuel-Costa, David; Silva-Marcos, J I; Wegman, Daniel

    2015-01-01T23:59:59.000Z

    We study leptonic CP violation from a new perspective. For Majorana neutrinos, a new parametrization for leptonic mixing of the form $V=O_{23} O_{12} K_{a}^{i}\\cdot O$ reveals interesting aspects that are less clear in the standard parametrization. We identify several important scenario-cases with mixing angles in agreement with experiment and leading to large leptonic CP violation. If neutrinos happen to be quasi-degenerate, this new parametrization might be very useful, e.g., in reducing the number of relevant parameters of models.

  13. Neutrinos and Collider Physics

    E-Print Network [OSTI]

    Frank F. Deppisch; P. S. Bhupal Dev; Apostolos Pilaftsis

    2015-03-09T23:59:59.000Z

    We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with $R$-parity violation. In the simplest Type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the LHC for leptogenesis are also studied.

  14. Neutrinos and Collider Physics

    E-Print Network [OSTI]

    Deppisch, Frank F; Pilaftsis, Apostolos

    2015-01-01T23:59:59.000Z

    We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with $R$-parity violation. In the simplest Type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the LHC for leptogenesis are also studied.

  15. LSND neutrino oscillation results

    SciTech Connect (OSTI)

    Louis, W.C.

    1996-06-01T23:59:59.000Z

    In the past several years, a number of experiments have searched for neutrino oscillations, where a neutrino of one type (say {bar {nu}}{sub {mu}}) spontaneously transforms into a neutrino of another type (say {bar {nu}}{sub e}). For this phenomenon to occur, neutrinos must be massive and the apparent conservation law of lepton families must be violated. In 1995 the LSND experiment published data showing candidate events that are consistent with {bar {nu}}{sub {mu}} oscillations. Additional data are reported here which provide stronger evidence for neutrino oscillations.

  16. Probing lepton number violation on three frontiers

    SciTech Connect (OSTI)

    Deppisch, Frank F. [Department of Physics and Astronomy, University College London (United Kingdom)

    2013-12-30T23:59:59.000Z

    Neutrinoless double beta decay constitutes the main probe for lepton number violation at low energies, motivated by the expected Majorana nature of the light but massive neutrinos. On the other hand, the theoretical interpretation of the (non-)observation of this process is not straightforward as the Majorana neutrinos can destructively interfere in their contribution and many other New Physics mechanisms can additionally mediate the process. We here highlight the potential of combining neutrinoless double beta decay with searches for Tritium decay, cosmological observations and LHC physics to improve the quantitative insight into the neutrino properties and to unravel potential sources of lepton number violation.

  17. Search for heavy Majorana neutrinos in $\\mu^\\pm \\mu^\\pm$+jets events in proton-proton collisions at $\\sqrt{s}$ = 8 TeV

    E-Print Network [OSTI]

    Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Lauwers, Jasper; Luyckx, Sten; Ochesanu, Silvia; Rougny, Romain; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Daci, Nadir; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Maes, Michael; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Dobur, Didar; Favart, Laurent; Gay, Arnaud; Grebenyuk, Anastasia; Léonard, Alexandre; Mohammadi, Abdollah; Pernič, Luca; Randle-conde, Aidan; Reis, Thomas; Seva, Tomislav; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Zenoni, Florian; Adler, Volker; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Costantini, Silvia; Crucy, Shannon; Fagot, Alexis; Garcia, Guillaume; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Poyraz, Deniz; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bruno, Giacomo; Castello, Roberto; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jafari, Abideh; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Nuttens, Claude; Pagano, Davide; Perrini, Lucia; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Dos Reis Martins, Thiago; Molina, Jorge; Mora Herrera, Clemencia; Pol, Maria Elena; Rebello Teles, Patricia; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santaolalla, Javier; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Bernardes, Cesar Augusto; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Aleksandrov, Aleksandar; Genchev, Vladimir; Hadjiiska, Roumyana; Iaydjiev, Plamen; Marinov, Andrey; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Cheng, Tongguang; Du, Ran; Jiang, Chun-Hua; Plestina, Roko; Romeo, Francesco; Tao, Junquan; Wang, Zheng; Asawatangtrakuldee, Chayanit; Ban, Yong; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Xu, Zijun; Zhang, Fengwangdong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Cabrera, Andrés; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Rykaczewski, Hans; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Radi, Amr; Kadastik, Mario; Murumaa, Marion; Raidal, Martti; Tiko, Andres; Eerola, Paula; Voutilainen, Mikko; Härkönen, Jaakko; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma

    2015-01-01T23:59:59.000Z

    A search is performed for heavy Majorana neutrinos (N) using an event signature defined by two muons of the same charge and two jets ($\\mu^\\pm \\mu^\\pm \\mathrm{j j}$). The data correspond to an integrated luminosity of 19.7 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC. No excess of events is observed beyond the expected standard model background and upper limits are set on $|V_{\\mu\\mathrm{N}}|^2$ as a function of Majorana neutrino mass $\\mathrm{m}_{\\mathrm{N}}$ for masses in the range of 40-500 GeV, where $|V_{\\mu\\mathrm{N}}|$ is the mixing element of the heavy neutrino with the standard model muon neutrino. The limits obtained are $|V_{\\mu\\mathrm{N}}|^2 \\le 0.00470$ for $\\mathrm{m}_{\\mathrm{N}} = 90$ GeV, $|V_{\\mu\\mathrm{N}}|^2 \\le 0.0123$ for $\\mathrm{m}_{\\mathrm{N}} = 200$ GeV, and $|V_{\\mu\\mathrm{N}}|^2 \\le 0.583$ for $\\mathrm{m}_{\\mathrm{N}} = 500$ GeV. These results extend considerably the regions excluded by previous direct se...

  18. Implications of theta_13 on Fritzsch-like lepton mass matrices

    E-Print Network [OSTI]

    Fakay, Priyanka; Verma, Rohit; Ahuja, Gulsheen; Gupta, Manmohan

    2013-01-01T23:59:59.000Z

    Implications of the lepton mixing angles, in particular of theta_13, have been investigated for minimal as well as non-minimal Fritzsch-like textures for the case of Majorana neutrinos. Both, in minimal texture (texture 6 zero lepton mass matrices) and non-minimal textures (two cases of texture 5 zero lepton mass matrices), inverted hierarchy and degenerate scenario of neutrino masses have been ruled out. The implications of theta_13 have been investigated on the lightest neutrino mass m_\

  19. Implications of theta_13 on Fritzsch-like lepton mass matrices

    E-Print Network [OSTI]

    Priyanka Fakay; Samandeep Sharma; Rohit Verma; Gulsheen Ahuja; Manmohan Gupta

    2013-01-25T23:59:59.000Z

    Implications of the lepton mixing angles, in particular of theta_13, have been investigated for minimal as well as non-minimal Fritzsch-like textures for the case of Majorana neutrinos. Both, in minimal texture (texture 6 zero lepton mass matrices) and non-minimal textures (two cases of texture 5 zero lepton mass matrices), inverted hierarchy and degenerate scenario of neutrino masses have been ruled out. The implications of theta_13 have been investigated on the lightest neutrino mass m_\

  20. Isospin-Violating Dark Matter and Neutrinos From the Sun

    E-Print Network [OSTI]

    Shao-Long Chen; Yue Zhang

    2011-06-20T23:59:59.000Z

    We study the indirect detection of dark matter through neutrino flux from their annihilation in the center of the Sun, in a class of theories where the dark matter-nucleon spin-independent interactions break the isospin symmetry. We point out that, while the direct detection bounds with heavy targets like Xenon are weakened and reconciled with the positive signals in DAMA and CoGeNT experiments, the indirect detection using neutrino telescopes can impose a relatively stronger constraint and brings tension to such explanation, if the annihilation is dominated by heavy quark or $\\tau$-lepton final states. As a consequence, the qualified isospin violating dark matter candidate has to preferably annihilate into light flavors.

  1. Neutrino Oscillation Physics

    SciTech Connect (OSTI)

    Kayser, Boris

    2012-06-01T23:59:59.000Z

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

  2. Nonzero {theta}{sub 13} for neutrino mixing in a supersymmetric B-L gauge model with T{sub 7} lepton flavor symmetry

    SciTech Connect (OSTI)

    Cao Qinghong [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, U.S.A (United States); Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Khalil, Shaaban [Centre for Theoretical Physics, The British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Okada, Hiroshi [School of Physics, KIAS, Seoul 130-722 (Korea, Republic of)

    2011-10-01T23:59:59.000Z

    We discuss how {theta}{sub 13}{ne}0 is accommodated in a recently proposed renormalizable model of neutrino mixing using the non-Abelian discrete symmetry T{sub 7} in the context of a supersymmetric extension of the standard model with gauged U(1){sub B-L}. We predict a correlation between {theta}{sub 13} and {theta}{sub 23}, as well as the effective neutrino mass m{sub ee} in neutrinoless double beta decay.

  3. Investigating texture six zero lepton mass matrices

    E-Print Network [OSTI]

    Mahajan, Neelu; Gupta, Manmohan; Gill, P S

    2013-01-01T23:59:59.000Z

    All possible hermitian texture 6 zero Fritzsch like as well as non Fritzsch like lepton mass matrices (144 combinations in all) have been investigated for both Majorana and Dirac neutrinos for their compatibility with the current neutrino oscillation data, keeping in mind the hierarchy of neutrino masses. All the combinations considered here are ruled out by the existing data in the case of inverted hierarchy and degenerate scenario of Majorana neutrino masses. For Majorana neutrinos with normal hierarchy, we find that out of 144 combinations, only 16 possibilities can accommodate the experimental data. Assuming neutrinos to be Dirac particles, normal hierarchy, inverted hierarchy as well as degenerate neutrinos are ruled out for all the combinations.

  4. High energy neutrino telescopes as a probe of the neutrino mass mechanism

    E-Print Network [OSTI]

    Kfir Blum; Anson Hook; Kohta Murase

    2014-08-17T23:59:59.000Z

    We show that measurements of the spectral shape and flavor ratios of high energy astrophysical neutrinos at neutrino telescopes can be sensitive to the details of the neutrino mass mechanism. We propose a simple model for Majorana neutrino mass generation that realizes the relevant parameter space, in which small explicit lepton number violation is mediated to the Standard Model through the interactions of a light scalar. IceCube, with about ten years of exposure time, could reveal the presence of anomalous neutrino self-interactions. Precision electroweak and lepton flavor laboratory experiments and a determination of the total neutrino mass from cosmology would provide consistency checks on the interpretation of a signal.

  5. Neutrino Physics: A Selective Overview

    E-Print Network [OSTI]

    Scott M. Oser

    2006-04-11T23:59:59.000Z

    Neutrinos in the Standard Model of particle physics are massless, neutral fermions that seemingly do little more than conserve 4-momentum, angular momentum, lepton number, and lepton flavour in weak interactions. In the last decade conclusive evidence has demonstrated that the Standard Model's description of neutrinos does not match reality. We now know that neutrinos undergo flavour oscillations, violating lepton flavour conservation and implying that neutrinos have non-zero mass. A rich oscillation phenomenology then becomes possible, including matter-enhanced oscillation and possibly CP violation in the neutrino sector. Extending the Standard Model to include neutrino masses requires the addition of new fields and mass terms, and possibly new methods of mass generation. In this review article I will discuss the evidence that has established the existence of neutrino oscillation, and then highlight unresolved issues in neutrino physics, such as the nature of three-generational mixing (including CP-violating effects), the origins of neutrino mass, the possible existence of light sterile neutrinos, and the difficult question of measuring the absolute mass scale of neutrinos.

  6. Relating quarks and leptons with the T7 flavour group

    E-Print Network [OSTI]

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

    2014-01-01T23:59:59.000Z

    In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

  7. Are the B decay anomalies related to neutrino oscillations?

    E-Print Network [OSTI]

    Boucenna, Sofiane M; Vicente, Avelino

    2015-01-01T23:59:59.000Z

    Neutrino oscillations are solidly established, with a hint of CP violation just emerging. Similarly, there are hints of lepton universality violation in $b \\to s$ transitions at the level of $2.6 \\sigma$. By assuming that the unitary transformation between weak and mass charged leptons equals the leptonic mixing matrix measured in neutrino oscillation experiments, we predict several lepton flavor violating (LFV) B meson decays. We are led to the tantalizing possibility that some LFV branching ratios for B decays correlate with the leptonic CP phase $\\delta$ characterizing neutrino oscillations. Moreover, we also consider implications for $\\ell_i \\to \\ell_j \\ell_k \\ell_k$ decays.

  8. B-L Neutrinos

    E-Print Network [OSTI]

    Cahill, K E

    1999-01-01T23:59:59.000Z

    Neutrino masses and mixings are analyzed in terms of left-handed fields and a 6x6 complex symmetric mass matrix whose singular values are the neutrino masses. An angle theta_nu characterizes the kind of the neutrinos, with theta_nu=0 for Dirac neutrinos and theta_nu=pi/2 for Majorana neutrinos. At theta_nu = 0 baryon-minus-lepton number is conserved. If theta_nu is approximately zero, the six neutrino masses coalesce into three nearly degenerate pairs. Thus the tiny mass differences exhibited in the solar and atmospheric neutrino experiments are naturally explained by the approximate conservation of B-L. Neutrinos are nearly Dirac fermions. This B-L model leads to these predictions: neutrinos oscillate mainly between flavor eigenfields and sterile eigenfields, and so neither KARMEN, nor SNO, nor BooNE will detect the appearance of neutrinos or antineutrinos; neutrinos may well be of cosmological importance; in principle the disappearance of the tau neutrino should be observable; and neutrinoless double-beta d...

  9. B-L Neutrinos

    E-Print Network [OSTI]

    Kevin Cahill

    2000-06-19T23:59:59.000Z

    Neutrino masses and mixings are analyzed in terms of left-handed fields and a 6x6 complex symmetric mass matrix whose singular values are the neutrino masses. An angle theta_nu characterizes the kind of the neutrinos, with theta_nu=0 for Dirac neutrinos and theta_nu=pi/2 for Majorana neutrinos. At theta_nu = 0 baryon-minus-lepton number is conserved. If theta_nu is approximately zero, the six neutrino masses coalesce into three nearly degenerate pairs. Thus the tiny mass differences exhibited in the solar and atmospheric neutrino experiments are naturally explained by the approximate conservation of B-L. Neutrinos are nearly Dirac fermions. This B-L model leads to these predictions: neutrinos oscillate mainly between flavor eigenfields and sterile eigenfields, and so the appearance of neutrinos and antineutrinos is suppressed; neutrinos may well be of cosmological importance; in principle the disappearance of the tau neutrino should be observable; and neutrinoless double-beta decay is suppressed by an extra factor of 10^(-5) and so will not be seen in the Heidelberg/Moscow, IGEX, GENIUS, or CUORE experiments.

  10. Natural fourth generation of leptons

    E-Print Network [OSTI]

    Oleg Antipin; Matti Heikinheimo; Kimmo Tuominen

    2009-09-14T23:59:59.000Z

    We consider implications of a fourth generation of leptons, allowing for the most general mass patterns for the fourth generation neutrino. We determine the constraints due to the precision electroweak measurements and outline the signatures to search for at the LHC experiments. As a concrete framework to apply these results we consider the minimal walking technicolor (MWTC) model where the matter content, regarding the electroweak quantum numbers, corresponds to a fourth generation.

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

    SciTech Connect (OSTI)

    Vergados, J. D. [Physics Department, University of Ioannina, Ioannina, GR 451 10, Greece and Theory Division, CERN 1211, Geneva 23 (Greece)

    2011-12-16T23:59:59.000Z

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

  12. Neutrino self-energy operator and neutrino magnetic moment

    SciTech Connect (OSTI)

    Dobrynina, A. A., E-mail: elenan@uniyar.ac.ru; Mikheev, N. V.; Narynskaya, E. N. [Yaroslavl State University (Russian Federation)] [Yaroslavl State University (Russian Federation)

    2013-11-15T23:59:59.000Z

    A simple method for calculating the magnetic moment of a massive neutrino on the basis of its self-energy operator is presented. An expression for the magnetic moment of a massive neutrino in an external electromagnetic field is obtained in the R{sub {xi}} gauge for the case of an arbitrary ratio of the lepton and W-boson masses.

  13. Neutrino mass matrix

    SciTech Connect (OSTI)

    Strobel, E.L.

    1985-01-01T23:59:59.000Z

    Given the many conflicting experimental results, examination is made of the neutrino mass matrix in order to determine possible masses and mixings. It is assumed that the Dirac mass matrix for the electron, muon, and tau neutrinos is similar in form to those of the quarks and charged leptons, and that the smallness of the observed neutrino masses results from the Gell-Mann-Ramond-Slansky mechanism. Analysis of masses and mixings for the neutrinos is performed using general structures for the Majorana mass matrix. It is shown that if certain tentative experimental results concerning the neutrino masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. A very recent experimental neutrino mass result and its implications are discussed. Some general properties of matrices with structure similar to the Dirac mass matrices are discussed.

  14. Guesswork for Dirac and Majorana neutrino mass matrices

    E-Print Network [OSTI]

    W. Krolikowski

    2004-01-14T23:59:59.000Z

    In the framework of seesaw mechanism with three neutrino flavors, we propose tentatively an efficient parametrization for the spectra of Dirac and righthanded Majorana neutrino mass matrices in terms of three free parameters. Two of them are related to (and determined by) the corresponding parameters introduced previously for the mass spectra of charged leptons and up and down quarks. The third is determined from the experimental estimate of solar $\\Delta m^2_{21}$. Then, the atmospheric $\\Delta m^2_{32}$ is {\\it predicted} close to its experimental estimation. With the use of these three parameters all light active-neutrino masses $ m_1 < m_2 < m_3$ and heavy sterile-neutrino masses $ M_1 < M_2 < M_3$ are readily evaluated. The latter turn out much more {\\it hierarchical} than the former. The lightest heavy mass $ M_1$ comes out to be of the order $O(10^6 {\\rm GeV})$ so, it is too light to imply that the mechanism of baryogenesis through thermal leptogenesis might work.

  15. Neutrino Masses and Flavor Mixing

    E-Print Network [OSTI]

    Fritzsch, Harald

    2015-01-01T23:59:59.000Z

    We discuss the neutrino oscillations, using texture zero mass matrices for the leptons. The reactor mixing angle $\\theta^{}_{l}$ is calculated. The ratio of the masses of two neutrinos is determined by the solar mixing angle. We can calculate the masses of the three neutrinos: $m_1$ $\\approx$ 0.003 eV - $m_2$ $\\approx$ 0.012 eV - $m_3$ $\\approx$ 0.048 eV.

  16. Neutrino Masses and Flavor Mixing

    E-Print Network [OSTI]

    Harald Fritzsch

    2015-03-06T23:59:59.000Z

    We discuss the neutrino oscillations, using texture zero mass matrices for the leptons. The reactor mixing angle $\\theta^{}_{l}$ is calculated. The ratio of the masses of two neutrinos is determined by the solar mixing angle. We can calculate the masses of the three neutrinos: $m_1$ $\\approx$ 0.003 eV - $m_2$ $\\approx$ 0.012 eV - $m_3$ $\\approx$ 0.048 eV.

  17. A new multi-dimensional general relativistic neutrino hydrodynamics code for core-collapse supernovae. IV. The neutrino signal

    SciTech Connect (OSTI)

    Müller, Bernhard [Monash Center for Astrophysics, School of Mathematical Sciences, Building 28, Monash University, Victoria 3800 (Australia); Janka, Hans-Thomas, E-mail: bernhard.mueller@monash.edu, E-mail: bjmuellr@mpa-garching.mpg.de, E-mail: thj@mpa-garching.mpg.de [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2014-06-10T23:59:59.000Z

    Considering six general relativistic, two-dimensional (2D) supernova (SN) explosion models of progenitor stars between 8.1 and 27 M {sub ?}, we systematically analyze the properties of the neutrino emission from core collapse and bounce to the post-explosion phase. The models were computed with the VERTEX-COCONUT code, using three-flavor, energy-dependent neutrino transport in the ray-by-ray-plus approximation. Our results confirm the close similarity of the mean energies, (E), of ?-bar {sub e} and heavy-lepton neutrinos and even their crossing during the accretion phase for stars with M ? 10 M {sub ?} as observed in previous 1D and 2D simulations with state-of-the-art neutrino transport. We establish a roughly linear scaling of ?E{sub ?-bar{sub e}}? with the proto-neutron star (PNS) mass, which holds in time as well as for different progenitors. Convection inside the PNS affects the neutrino emission on the 10%-20% level, and accretion continuing beyond the onset of the explosion prevents the abrupt drop of the neutrino luminosities seen in artificially exploded 1D models. We demonstrate that a wavelet-based time-frequency analysis of SN neutrino signals in IceCube will offer sensitive diagnostics for the SN core dynamics up to at least ?10 kpc distance. Strong, narrow-band signal modulations indicate quasi-periodic shock sloshing motions due to the standing accretion shock instability (SASI), and the frequency evolution of such 'SASI neutrino chirps' reveals shock expansion or contraction. The onset of the explosion is accompanied by a shift of the modulation frequency below 40-50 Hz, and post-explosion, episodic accretion downflows will be signaled by activity intervals stretching over an extended frequency range in the wavelet spectrogram.

  18. Search for Lepton Flavour Violating Decays of Heavy Resonances and Quantum Black Holes to electron/muon Pairs in pp Collisions at a centre of mass energy of 8 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2015-01-01T23:59:59.000Z

    A search for heavy states decaying into the e$\\mu$ final state has been performed using an integrated luminosity of $19.7~\\text{fb}^{-1}$ of $8\\,\\text{TeV}$ proton-proton collision data recorded with the CMS detector at the LHC. No evidence for physics beyond the Standard Model is observed in the invariant mass spectrum of selected e$\\mu$ pairs. 95$\\%$ CL upper limits are set on the cross section times branching ratio of different signals arising in theories of new physics with lepton flavour violation in interactions involving charged leptons. In the framework of TeV-scale quantum gravity from a renormalization of Newton's constant, exclusion limits are set on the production threshold of quantum black holes for threshold masses below $1.99\\,\\text{TeV}$, and in extra-dimensional models the bounds range from $2.36\\,\\text{TeV}$ for one extra dimension to $3.63\\,\\text{TeV}$ for six extra dimensions. Scenarios of resonant tau sneutrino LSP production in R-parity violating supersymmetry are excluded for LSP masses...

  19. Constraints on Non-Standard Neutrino Interactions and Unparticle Physics with Neutrino-Electron Scattering at the Kuo-Sheng Nuclear Power Reactor

    E-Print Network [OSTI]

    M. Deniz er al.; TEXONO Collaboration

    2010-08-09T23:59:59.000Z

    Neutrino-electron scatterings are purely leptonic processes with robust Standard Model (SM) predictions. Their measurements can therefore provide constraints to physics beyond SM. The $\

  20. Performance of ?q-lepton reconstruction and identification in CMS

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2012-01-01T23:59:59.000Z

    The performance of tau-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at sqrt(s)=7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns collected with the CMS detector at the LHC. The tau leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using tau leptons produced in Z-boson decays. The tau-lepton misidentification rates for jets and electrons are determined.

  1. Electromagnetic properties of massive neutrinos

    SciTech Connect (OSTI)

    Dobrynina, A. A., E-mail: aleksandradobrynina@rambler.ru; Mikheev, N. V.; Narynskaya, E. N. [Demidov Yaroslavl State University (Russian Federation)] [Demidov Yaroslavl State University (Russian Federation)

    2013-10-15T23:59:59.000Z

    The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

  2. Phenomenological relations for neutrino masses and mixing parameters

    SciTech Connect (OSTI)

    Khruschov, V. V., E-mail: khru@imp.kiae.ru [National Research Center Kurchatov Institute (Russian Federation)

    2013-11-15T23:59:59.000Z

    Phenomenological relations for masses, angles, and CP phases in the neutrino mixing matrix are proposed with allowance for available experimental data. For the case of CP violation in the lepton sector, an analysis of the possible structure of the neutrino mass matrix and a calculation of the neutrino mass features and the Dirac CP phase for the bimodal-neutrino model are performed. The values obtained in this way can be used to interpret and predict the results of various neutrino experiments.

  3. Neutrino Physics: Status and Prospects

    E-Print Network [OSTI]

    K. Scholberg

    2003-08-05T23:59:59.000Z

    This pedagogical overview will cover the current status of neutrino physics from an experimentalist's point of view, focusing primarily on oscillation studies. The evidence for neutrino oscillations will be presented, along with the prospects for further refinement of observations in each of the indicated regions of two-flavor oscillation parameter space. The next steps in oscillation physics will then be covered (under the assumption of three-flavor mixing): the quest for $\\theta_{13}$, mass hierarchy and, eventually, leptonic CP violation. Prospects for non-oscillation aspects of neutrino physics, such as kinematic tests for absolute neutrino mass and double beta decay searches, will also be discussed briefly.

  4. Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\\sqrt{s} with the ATLAS Detector

    SciTech Connect (OSTI)

    Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; /Freiburg U. /Oklahoma U. /Barcelona, IFAE /Geneva U. /Oxford U. /Baku, Inst. Phys. /Oklahoma State U. /Michigan State U. /Tel Aviv U. /Orsay, LAL /INFN, Milan /Milan U. /INFN, Udine /ICTP, Trieste /Brookhaven /Hampton U. /Yale U. /Heidelberg, Max Planck Inst. /Munich U. /Queen Mary, U. of London /Rutherford

    2012-06-20T23:59:59.000Z

    The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.

  5. Status and implications of neutrino masses: a brief panorama

    E-Print Network [OSTI]

    Valle, J W F

    2015-01-01T23:59:59.000Z

    With the historic discovery of the Higgs boson our picture of particle physics would have been complete were it not for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role in elucidating the nature of dark matter and cosmic inflation.

  6. Low and high energy phenomenology of quark-lepton complementarity scenarios

    SciTech Connect (OSTI)

    Hochmuth, Kathrin A. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Munich (Germany); Rodejohann, Werner [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany)

    2007-04-01T23:59:59.000Z

    We conduct a detailed analysis of the phenomenology of two predictive seesaw scenarios leading to quark-lepton complementarity. In both cases we discuss the neutrino mixing observables and their correlations, neutrinoless double beta decay and lepton flavor violating decays such as {mu}{yields}e{gamma}. We also comment on leptogenesis. The first scenario is disfavored on the level of one to two standard deviations, in particular, due to its prediction for |U{sub e3}|. There can be resonant leptogenesis with quasidegenerate heavy and light neutrinos, which would imply sizable cancellations in neutrinoless double beta decay. The decays {mu}{yields}e{gamma} and {tau}{yields}{mu}{gamma} are typically observable unless the SUSY masses approach the TeV scale. In the second scenario leptogenesis is impossible. It is, however, in perfect agreement with all oscillation data. The prediction for {mu}{yields}e{gamma} is in general too large, unless the SUSY masses are in the range of several TeV. In this case {tau}{yields}e{gamma} and {tau}{yields}{mu}{gamma} are unobservable.

  7. A select overview of neutrino experiments

    SciTech Connect (OSTI)

    Stefanski, Raymond J.

    2004-11-01T23:59:59.000Z

    The relationship between the lepton sector and the quark sector is an interesting source of discourse in the current theoretical climate. Models that might someday supersede the Standard Model typically require quark structure, with implications for the lepton sector. This talk will explore some of the consequences of newer models, in the context of certain neutrino experiments.

  8. Two-Higgs Leptonic Minimal Flavour Violation

    E-Print Network [OSTI]

    Botella, F J; Nebot, M; Rebelo, M N

    2011-01-01T23:59:59.000Z

    We construct extensions of the Standard Model with two Higgs doublets, where there are flavour changing neutral currents both in the quark and leptonic sectors, with their strength fixed by the fermion mixing matrices $V_{CKM}$ and $V_{PMNS}$. These models are an extension to the leptonic sector of the class of models previously considered by Branco, Grimus and Lavoura, for the quark sector. We consider both the cases of Dirac and Majorana neutrinos and identify the minimal discrete symmetry required in order to implement the models in a natural way.

  9. Renormalization group invariant of lepton Yukawa couplings

    E-Print Network [OSTI]

    Tsuyuki, Takanao

    2015-01-01T23:59:59.000Z

    By using quark Yukawa matrices only, we can construct renormalization invariants that are exact at the one-loop level in the standard model. One of them $I^q$ is accidentally consistent with unity, even though quark masses are strongly hierarchical. We calculate a lepton version of the invariant $I^l$ for Dirac and Majorana neutrino cases and find that $I^l$ can be also close to unity. For the Dirac neutrino case, if we assume $I^q=I^l$, we can deduce that the hierarchy of neutrino masses is inverted, and the lightest neutrino mass is 3.0 meV to 8.8 meV.

  10. SU4228472 Simpson's Neutrino and the Singular SeeSaw

    E-Print Network [OSTI]

    Allen, Theodore J.

    Burjassot, Valâ??encia, Spain Abstract We derive explicit forms for the neutrino and lepton ``mixing­matrices ``natural'') massive neutrino in gauge theories is of the two­component ``Majorana'' type, it becomes Majorana neutrinos whose contributions cancel each other. If the two are degenerate, or nearly so, they e

  11. Lepton-flavored dark matter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kile, Jennifer; Kobach, Andrew; Soni, Amarjit

    2015-05-01T23:59:59.000Z

    In this work, we address two paradoxes. The first is that the measured dark-matter relic density can be satisfied with new physics at O(100 GeV–1 TeV), while the null results from direct-detection experiments place lower bounds of O(10 TeV) on a new-physics scale. The second puzzle is that the severe suppression of lepton-flavor-violating processes involving electrons, e.g. ? ? 3e, ? ? e??, etc., implies that generic new-physics contributions to lepton interactions cannot exist below O(10–100 TeV), whereas the 3.6? deviation of the muon g – 2 from the standard model can be explained by a new physics scale lepton-flavor interaction that couples at tree level only to ?- and ?-flavored leptons and the dark sector. Dark matter thus interacts appreciably only with particles of ? and ? flavor at tree level and has loop-suppressed couplings to quarks and electrons. Remarkably, if such a gauged flavor interaction exists at a scale O(100 GeV–1 TeV), it allows for a consistent phenomenological framework, compatible with the muon g – 2, the relic density, direct detection, indirect detection, charged-lepton decays, neutrino trident production, and results from hadron and e?e? colliders. We suggest experimental tests for these ideas at colliders and for low-energy observables. (author)

  12. Lepton-flavored dark matter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kile, Jennifer; Kobach, Andrew; Soni, Amarjit

    2015-05-01T23:59:59.000Z

    In this work, we address two paradoxes. The first is that the measured dark-matter relic density can be satisfied with new physics at O(100 GeV–1 TeV), while the null results from direct-detection experiments place lower bounds of O(10 TeV) on a new-physics scale. The second puzzle is that the severe suppression of lepton-flavor-violating processes involving electrons, e.g. ? ? 3e, ? ? e??, etc., implies that generic new-physics contributions to lepton interactions cannot exist below O(10–100 TeV), whereas the 3.6? deviation of the muon g – 2 from the standard model can be explained by a new physics scale more »TeV). Here, we suggest that it may not be a coincidence that both the muon g – 2 and the relic density can be satisfied by a new-physics scale ?1 TeV. We consider the possibility of a gauged lepton-flavor interaction that couples at tree level only to ?- and ?-flavored leptons and the dark sector. Dark matter thus interacts appreciably only with particles of ? and ? flavor at tree level and has loop-suppressed couplings to quarks and electrons. Remarkably, if such a gauged flavor interaction exists at a scale O(100 GeV–1 TeV), it allows for a consistent phenomenological framework, compatible with the muon g – 2, the relic density, direct detection, indirect detection, charged-lepton decays, neutrino trident production, and results from hadron and e?e? colliders. We suggest experimental tests for these ideas at colliders and for low-energy observables. (author)« less

  13. Small Neutrino Masses from Supersymmetry Breaking

    E-Print Network [OSTI]

    Arkani-Hamed, Nima

    2009-01-01T23:59:59.000Z

    neutrino mass matrices. The above Majorana and Dirac casesMajorana mass for N of the order F/M ? 100GeV, yielding a LR neutrino mass matrixMajorana masses M and couplings to the lepton doublets: L = M NN + ?LNH where M and ? are mass matrices.

  14. Gauge Trimming of Neutrino Masses

    SciTech Connect (OSTI)

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

    2006-12-01T23:59:59.000Z

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

  15. Search for WW and WZ production in lepton, neutrino plus jets final states at CDF Run II and Silicon module production and detector control system for the ATLAS SemiConductor Tracker

    SciTech Connect (OSTI)

    Sfyrla, Anna; /Geneva U.

    2008-03-01T23:59:59.000Z

    In the first part of this work, we present a search for WW and WZ production in charged lepton, neutrino plus jets final states produced in p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron, using 1.2 fb{sup -1} of data accumulated with the CDF II detector. This channel is yet to be observed in hadron colliders due to the large singleWplus jets background. However, this decay mode has a much larger branching fraction than the cleaner fully leptonic mode making it more sensitive to anomalous triple gauge couplings that manifest themselves at higher transverse W momentum. Because the final state is topologically similar to associated production of a Higgs boson with a W, the techniques developed in this analysis are also applicable in that search. An Artificial Neural Network has been used for the event selection optimization. The theoretical prediction for the cross section is {sigma}{sub WW/WZ}{sup theory} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 2.09 {+-} 0.14 pb. They measured N{sub Signal} = 410 {+-} 212(stat) {+-} 102(sys) signal events that correspond to a cross section {sigma}{sub WW/WZ} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 1.47 {+-} 0.77(stat) {+-} 0.38(sys) pb. The 95% CL upper limit to the cross section is estimated to be {sigma} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) < 2.88 pb. The second part of the present work is technical and concerns the ATLAS SemiConductor Tracker (SCT) assembly phase. Although technical, the work in the SCT assembly phase is of prime importance for the good performance of the detector during data taking. The production at the University of Geneva of approximately one third of the silicon microstrip end-cap modules is presented. This collaborative effort of the university of Geneva group that lasted two years, resulted in 655 produced modules, 97% of which were good modules, constructed within the mechanical and electrical specifications and delivered in the SCT collaboration for assembly on the end-cap disks. The SCT end-caps and barrels consist of 4088 silicon modules, with a total of 6.3 million readout channels. The coherent and safe operation of the SCT during commissioning and subsequent operation is the essential task of the Detector Control System (DCS). The main building blocks of the DCS are the cooling system, the power supplies and the environmental system. The DCS has been initially developed for the SCT assembly phase and this system is described in the present work. Particular emphasis is given in the environmental hardware and software components, that were my major contributions. Results from the DCS testing during the assembly phase are also reported.

  16. Natural Dirac Neutrinos from Warped Extra Dimension

    E-Print Network [OSTI]

    Jackson M. S. Wu

    2010-06-29T23:59:59.000Z

    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.

  17. Parallel hybrid textures of lepton mass matrices

    E-Print Network [OSTI]

    S. Dev; Shivani Gupta; Radha Raman Gautam

    2010-09-28T23:59:59.000Z

    We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type $CP$ violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.

  18. Parallel hybrid textures of lepton mass matrices

    SciTech Connect (OSTI)

    Dev, S.; Gupta, Shivani; Gautam, Radha Raman [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

    2010-10-01T23:59:59.000Z

    We analyze the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total 60 parallel hybrid texture structures can be grouped into 12 classes, and all the hybrid textures in the same class have identical physical implications. We examine all 12 classes under the assumption of nonfactorizable phases in the neutrino mass matrix. Five out of the total 12 classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type CP violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.

  19. Parallel hybrid textures of lepton mass matrices

    E-Print Network [OSTI]

    Dev, S; Gautam, Radha Raman

    2010-01-01T23:59:59.000Z

    We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type $CP$ violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.

  20. Classification of lepton mixing patterns from finite flavour symmetries

    E-Print Network [OSTI]

    Renato M. Fonseca; Walter Grimus

    2014-10-15T23:59:59.000Z

    Flavour symmetries have been used to constrain both quark and lepton mixing parameters. In particular, they can be used to completely fix the mixing angles. For the lepton sector, assuming that neutrinos are Majorana particles, we have derived the complete list of mixing patterns achievable in this way, as well as the symmetry groups associated to each case. Partial computer scans done in the past have hinted that such list is limited, and this does indeed turn out to be the case. In addition, most mixing patterns are already 3-sigma excluded by neutrino oscillation data.

  1. Search for Heavy Majorana Neutrinos in Same-Sign mumu+jets and ee+jets Events in pp Collisions at sqrt(s) = 7 GeV

    E-Print Network [OSTI]

    Giordano, Ferdinando

    2013-01-01T23:59:59.000Z

    neutrinos in neutrinoless double beta decay. Phys. Rev. D,non-observation of neutrinoless double beta decay [16], re-

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

    E-Print Network [OSTI]

    Amand Faessler

    2012-03-16T23:59:59.000Z

    The Neutrinoless double beta Decay allows to determine the effectice Majorana electron neutrino mass. For this the following conditions have to be satisfied: (i) The neutrino must be a Majorana particle, i. e. identical to the antiparticle. (ii) The half life has to be measured. (iii)The transition matrix element must be reliably calculated. (iv) The leading mechanism must be the light Majorana neutrino exchange. The present contribution studies the accuracy with which one can calculate by different methods: (1) Quasi-Particle Random Phase Approach (QRPA), (2) the Shell Model (SM), (3) the (before the variation) angular momentum projected Hartree-Fock-Bogoliubov method (PHFB)and the (4) Interacting Boson Approach (IBA). In the second part we investigate how to determine experimentally the leading mechanism for the Neutrinoless Double Beta Decay. Is it (a) the light Majorana neutrino exchange as one assumes to determine the effective Majorana neutrino mass, ist it the heavy left (b) or right handed (c) Majorana neutrino exchange allowed by left-right symmetric Grand Unified Theories (GUT's). Is it a mechanism due to Supersymmetry e.g. with gluino exchange and R-parity and lepton number violating terms. At the end we assume, that Klapdor et al. have indeed measured the Neutrinoless Double Beta Decay(, although contested,)and that the light Majorana neutrino exchange is the leading mechanism. With our matrix elements we obtain then an effective Majorana neutrino mass of: = 0.24 [eV], exp (pm) 0.02; theor. (pm) 0.01 [eV

  3. Flavor Mixing and CP Violation of Massive Neutrinos

    E-Print Network [OSTI]

    Zhi-zhong Xing

    2004-11-26T23:59:59.000Z

    We present an overview of recent progress in the phenomenological study of neutrino masses, lepton flavor mixing and CP violation. We concentrate on the model-independent properties of massive neutrinos, both in vacuum and in matter. Current experimental constraints on the neutrino mass spectrum and the lepton flavor mixing parameters are summarized. The Dirac- and Majorana-like phases of CP violation, which are associated respectively with the long-baseline neutrino oscillations and the neutrinoless double beta decay, are discussed in detail. The seesaw mechanism, the leptogenesis scenario and the strategies to construct lepton mass matrices are briefly described. The features of flavor mixing between one sterile neutrino and three active neutrinos are also explored.

  4. Neutrinos Are Nearly Dirac Fermions

    E-Print Network [OSTI]

    Cahill, K E

    1999-01-01T23:59:59.000Z

    Neutrino masses and mixings are analyzed in terms of left-handed fields and a 6x6 complex symmetric mass matrix whose singular values are the neutrino masses. An angle theta_nu characterizes the kind of the neutrinos, with theta_nu = 0 for Dirac neutrinos and theta_nu = pi/2 for Majorana neutrinos. If theta_nu = 0, then baryon-minus-lepton number is conserved. When theta_nu is approximately zero, the six neutrino masses coalesce into three nearly degenerate pairs. Thus the smallness of the differences in neutrino masses exhibited in the solar and atmospheric neutrino experiments and the stringent limits on neutrinoless double-beta decay are naturally explained if B-L is approximately conserved and neutrinos are nearly Dirac fermions. If one sets theta_nu = 0.0005, suppresses inter-generational mixing, and imposes a quark-like mass hierarchy, then one may fit the essential features of the solar, reactor, and atmospheric neutrino experiments with otherwise random mass matrices in the eV range. This B-L model le...

  5. Phenomenology of a leptonic goldstino and invisible Higgs boson decays

    E-Print Network [OSTI]

    Ignatios Antoniadis; Marc Tuckmantel; Fabio Zwirner

    2005-03-23T23:59:59.000Z

    Non-linearly realized supersymmetry, combined with the Standard Model field content and SU(3)XSU(2)XU(1) gauge invariance, permits local dimension-six operators involving a goldstino, a lepton doublet and a Higgs doublet. These interactions preserve total lepton number if the left-handed goldstino transforms as an antilepton. We discuss the resulting phenomenology, in the simple limit where the new couplings involve only one lepton family, thus conserving also lepton flavour. Both the Z boson and the Higgs boson can decay into a neutrino and a goldstino: the present limits from the invisible Z width and from other observables leave room for the striking possibility of a Higgs boson decaying dominantly, or at least with a sizable branching ratio, via such an invisible mode. We finally comment on the perspectives at hadron and lepton colliders, and on possible extensions of our analysis.

  6. Neutrinos Are Nearly Dirac Fermions

    E-Print Network [OSTI]

    Kevin Cahill

    2000-06-10T23:59:59.000Z

    Neutrino masses and mixings are analyzed in terms of left-handed fields and a 6x6 complex symmetric mass matrix whose singular values are the neutrino masses. An angle x_nu characterizes the kind of the neutrinos, with x_nu = 0 for Dirac neutrinos and x_nu = pi/2 for Majorana neutrinos. If x_nu = 0, then baryon-minus-lepton number is conserved. When x_nu is approximately zero, the six neutrino masses coalesce into three nearly degenerate pairs. Thus the smallness of the differences in neutrino masses exhibited in the solar and atmospheric neutrino experiments and the stringent limits on neutrinoless double beta decay are naturally explained if B-L is approximately conserved and neutrinos are nearly Dirac fermions. If one sets sin(x_nu) = 0.003, suppresses inter-generational mixing, and imposes a quark-like mass hierarchy, then one may fit the essential features of the solar, reactor, and atmospheric neutrino experiments with otherwise random mass matrices in the eV range. This B-L model leads to these predictions: neutrinos oscillate mainly between flavor eigenfields and sterile eigenfields, and so the probabilities of the appearance of neutrinos or antineutrinos are very small; neutrinos may well be of cosmological importance; in principle the disappearance of the tau neutrino should be observable; and neutrinoless double beta decay is suppressed by an extra factor of < 10^(-5) and hence will not be seen in the Heidelberg/Moscow, IGEX, GENIUS, or CUORE experiments.

  7. Neutrino production in [ital e][sup +][ital e[minus

    SciTech Connect (OSTI)

    Gluza, J.; Zralek, M. (Department of Field Theory and Particle Physics, Institute of Physics, University of Silesia, Uniwersytecka 4, PL-40-007 Katowice (Poland))

    1993-12-01T23:59:59.000Z

    The production of light and heavy ([nu][ital N]) and two heavy neutrinos ([ital NN]) in [ital e][sup +][ital e[minus

  8. Flavor $\\S_{4}$ [circle times operator] $\\Z_{2}$ symmetry and neutrino mixing

    E-Print Network [OSTI]

    Zhang, H

    2007-01-01T23:59:59.000Z

    We present a model of the lepton masses and flavor mixing based on the discrete group $S^{}_4\\otimes Z^{}_2$. In this model, all the charged leptons and neutrinos are assigned to the ${\\bf \\underline{3}}_\\alpha$ representation of $S^{}_4$ in the Yamanouchi bases. The charged lepton and neutrino masses are mainly determined by the vacuum expectation value structures of the Higgs fields. Our model predicts a nearly tri-bimaximal lepton flavor mixing pattern, which is fully in agreement with the current experimental results. The neutrino mass spectrum takes the nearly degenerate pattern, which may be well tested in the future precise experiments.

  9. Renormalization group invariant of lepton Yukawa couplings

    E-Print Network [OSTI]

    Takanao Tsuyuki

    2015-04-20T23:59:59.000Z

    By using quark Yukawa matrices only, we can construct renormalization invariants that are exact at the one-loop level in the standard model. One of them $I^q$ is accidentally consistent with unity, even though quark masses are strongly hierarchical. We calculate a lepton version of the invariant $I^l$ for Dirac and Majorana neutrino cases and find that $I^l$ can also be close to unity. For the Dirac neutrino and inverted hierarchy case, if the lightest neutrino mass is 3.0 meV to 8.8 meV, an equality $I^q=I^l$ can be satisfied. These invariants are not changed even if new particles couple to the standard model particles, as long as those couplings are generation independent.

  10. Entanglement in neutrino oscillations

    E-Print Network [OSTI]

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

    2009-04-17T23:59:59.000Z

    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 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.

  11. Constraints on the relic neutrino abundance and implications for cosmological neutrino mass limits

    SciTech Connect (OSTI)

    Bell, Nicole F.; /Fermilab

    2004-01-01T23:59:59.000Z

    The authors examine a mechanism which can lead to flavor transformation of neutrino-antineutrino asymmetries in the early universe, a process which is unavoidable when the neutrino mixing angles are large. This sets the best limit on the lepton number of the universe, and hence on the relic neutrino abundance. They also consider the consequences for the relic neutrino abundance if extra neutrino interactions are allowed, e.g., the coupling of the neutrinos to a light (compared to m{sub {nu}}) boson. For a wide range of couplings not excluded by other considerations, the relic neutrinos would annihilate to bosons at late times, and thus make a negligible contribution to the matter density today. This mechanism evades the neutrino mass limits arising from large scale structure.

  12. Neutrino Majorana Mass from Black Hole

    E-Print Network [OSTI]

    Yosuke Uehara

    2002-05-25T23:59:59.000Z

    We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of higher-dimensional spacetime can result in the production of a black hole, which emits 2 neutrinos. If neutrinos are Majorana particles, this process is equivalent to the free propagation of a neutrino with the insertion of the black hole. From this fact, we derive the neutrino Majorana mass. The result is completely consistent with the recently observed evidence of neutrinoless double beta decay. And the obtained neutrino Majorana mass satisfies the constraint from the density of the neutrino dark matter, which affects the cosmic structure formation. Furthermore, we can explain the ultrahigh energy cosmic rays by the Z-burst scenario with it.

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

    SciTech Connect (OSTI)

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

    2001-06-30T23:59:59.000Z

    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.

  14. A New Type of Resonant Neutrino Conversions Induced by Magnetic Fields

    E-Print Network [OSTI]

    S. Sahu; V. B. Semikoz; J. W. F. Valle

    1995-12-21T23:59:59.000Z

    We consider resonant neutrino conversions in magnetised matter, such as a degenerate electron gas. We show how magnetisation effects caused by axial vector interactions of neutrinos with the charged leptons in the medium can induce a new type of resonant neutrino conversion which may occur even in situations where the MSW effect does not occur, such as the case of degenerate or inverted neutrino mass spectra. Our new resonance may simultaneously affect anti-neutrino $\\bar{\

  15. CP violation in neutrino mass matrix

    E-Print Network [OSTI]

    Utpal Sarkar; Santosh K. Singh

    2006-08-03T23:59:59.000Z

    We constructed rephasing invariant measures of CP violation with elements of the neutrino mass matrix, in the basis in which the charged lepton mass matrix is diagonal. We discuss some examples of neutrino mass matrices with texture zeroes, where the present approach is applicable and demonstrate how it simplifies an analysis of CP violation. We applied our approach to study CP violation in all the phenomenologically acceptable 3-generation two-zero texture neutrino mass matrices and shown that in any of these cases there is only one CP phase which contributes to the neutrino oscillation experiment and there are no Majorana phases.

  16. A complete survey of texture zeros in the lepton mass matrices

    E-Print Network [OSTI]

    Ludl, Patrick Otto

    2014-01-01T23:59:59.000Z

    We perform a systematic and complete analysis of texture zeros in the lepton mass matrices and identify all viable and maximally restrictive cases of pairs (M_\\ell, M_D) and (M_\\ell, M_L), where M_\\ell, M_D and M_L are the charged-lepton, Dirac neutrino and Majorana neutrino mass matrices, respectively. To this end, we perform a thorough analysis of textures which are equivalent through weak-basis permutations. Furthermore, we introduce numerical measures for the predictivity of textures and apply them to the viable and maximally restrictive texture zero models. It turns out that for Dirac neutrinos these models can at most predict the smallest neutrino mass and the CKM-type phase of the mixing matrix. For Majorana neutrinos most models can, in addition, predict the effective neutrino mass for neutrinoless double beta decay.

  17. Leptonic CP Violation Phases, Quark-Lepton Similarity and Seesaw Mechanism

    E-Print Network [OSTI]

    Basudeb Dasgupta; Alexei Yu. Smirnov

    2014-05-20T23:59:59.000Z

    We explore generic features of the leptonic CP violation in the framework of the seesaw type I mechanism with similarity of the Dirac lepton and quarks mass matrices $m_D$. For this, we elaborate on the standard parametrization conditions which allow to simultaneously obtain the Dirac and Majorana phases. If the only origin of CP violation is the left-handed (LH) transformation which diagonalizes $m_D$ (similar to quarks), the leptonic CP violation is suppressed and the Dirac phase is close to $\\pi$ or to $0$ with $\\sin \\delta_{CP} \\approx (\\sin \\theta_{13}^q /\\sin \\theta_{13}) \\cos \\theta_{23} \\sin \\delta_q \\sim \\lambda^2 \\sin \\delta_q$. Here $\\lambda \\sim \\theta_C$, is the Cabibbo mixing angle, and $\\theta_{13}^q$ and $\\theta_{13}$ are the 1-3 mixing angles of quarks and leptons respectively. The Majorana phases $\\beta_1$ and $\\beta_2$ are suppressed as $\\lambda^3\\sin\\delta_q$. For Majorana neutrinos implied by seesaw, the right-handed (RH) transformations are important. We explore the simplest extension inspired by Left-Right (L-R) symmetry with small CKM-type CP violation. In this case, seesaw enhancement of the CP violation occurs due to strong hierarchy of the eigenvalues of $m_D$ leading to $\\delta_{CP} \\sim 1$. The enhancement is absent under the phase factorization conditions which require certain relations between parameters of the Majorana mass matrix of RH neutrinos.

  18. Confronting predictive texture zeros in lepton mass matrices with current data

    E-Print Network [OSTI]

    Luís M. Cebola; David Emmanuel-Costa; Ricardo González Felipe

    2015-04-24T23:59:59.000Z

    Several popular Ans\\"atze of lepton mass matrices that contain texture zeros are confronted with current neutrino observational data. We perform a systematic $\\chi^2$-analysis in a wide class of schemes, considering arbitrary Hermitian charged lepton mass matrices and symmetric mass matrices for Majorana neutrinos or Hermitian mass matrices for Dirac neutrinos. Our study reveals that several patterns are still consistent with all the observations at 68.27% confidence level, while some others are disfavored or excluded by the experimental data. The well-known Frampton-Glashow-Marfatia two-zero textures, hybrid textures and parallel structures, among others, are considered.

  19. Confronting predictive texture zeros in lepton mass matrices with current data

    E-Print Network [OSTI]

    Cebola, Luís M; Felipe, Ricardo González

    2015-01-01T23:59:59.000Z

    Several popular Ans\\"atze of lepton mass matrices that contain texture zeros are confronted with current neutrino observational data. We perform a systematic $\\chi^2$-analysis in a wide class of schemes, considering arbitrary Hermitian charged lepton mass matrices and symmetric mass matrices for Majorana neutrinos or Hermitian mass matrices for Dirac neutrinos. Our study reveals that several patterns are still consistent with all the observations at 68.27% confidence level, while some others are disfavored or excluded by the experimental data. The well-known Frampton-Glashow-Marfatia two-zero textures, hybrid textures and parallel structures, among others, are considered.

  20. Survey of lepton number violation via effective operators

    SciTech Connect (OSTI)

    Gouvea, Andre de; Jenkins, James [Northwestern University, Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

    2008-01-01T23:59:59.000Z

    We survey 129 lepton number violating effective operators, consistent with the minimal standard model gauge group and particle content, of mass dimension up to and including 11. Upon requiring that each one radiatively generates the observed neutrino masses, we extract an associated characteristic cutoff energy scale which we use to calculate other observable manifestations of these operators for a number of current and future experimental probes, concentrating on lepton number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson, lepton, and gauge boson decays. We also consider searches at hadron/lepton collider facilities in anticipation of the CERN LHC and the future ILC. We find that some operators are already disfavored by current data, while more are ripe to be probed by next-generation experiments. We also find that our current understanding of lepton mixing disfavors a subset of higher dimensional operators. While neutrinoless double-beta decay is the most promising signature of lepton number violation for the majority of operators, a handful is best probed by other means. We argue that a combination of constraints from various independent experimental sources will help to pinpoint the ''correct'' model of neutrino mass, or at least aid in narrowing down the set of possibilities.

  1. A Survey of Lepton Number Violation Via Effective Operators

    E-Print Network [OSTI]

    Andre de Gouvea; James Jenkins

    2007-08-09T23:59:59.000Z

    We survey 129 lepton number violating effective operators, consistent with the minimal Standard Model gauge group and particle content, of mass dimension up to and including eleven. Upon requiring that each one radiatively generates the observed neutrino masses, we extract an associated characteristic cutoff energy scale which we use to calculate other observable manifestations of these operators for a number of current and future experimental probes, concentrating on lepton number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson, lepton, and gauge boson decays. We also consider searches at hadron/lepton collider facilities in anticipation of the LHC and the future ILC. We find that some operators are already disfavored by current data, while more are ripe to be probed by next-generation experiments. We also find that our current understanding of lepton mixing disfavors a subset of higher dimensional operators. While neutrinoless double-beta decay is the most promising signature of lepton number violation for the majority of operators, a handful is best probed by other means. We argue that a combination of constraints from various independent experimental sources will help to pinpoint the ``correct'' model of neutrino mass, or at least aid in narrowing down the set of possibilities.

  2. Mass Spectrum and Number of Light Neutrinos: An Attempt of the Gauge Explanation

    E-Print Network [OSTI]

    Dyatlov, I T

    2009-01-01T23:59:59.000Z

    Symplectic flavour symmetry group Sp(n/2) (n is even) of n Majorana states does not allow for invariant Majorana masses. Only specific mass matrices with diagonal and nondiagonal elements are possible here. As a result of the spontaneous violation of flavour and chiral symmetries, a mass matrix could appear only for the number of flavours n = 6 and only together with R,L-symmetry violation (i.e., parity violation). The see-saw mechanism produces here three light and three heavy Dirac particles (neutrinos). The peculiarity of the observed light neutrino spectrum: two states located far from the third one, can be explained by certain simple properties of mass matrices appearing in Sp(3). The ordering of the states corresponds to normal mass hierarchy. Situation, when neutrino mass differences are significantly less than masses themselves, appears to be unrealizable here. Mixing angles for neutrinos can not be determined without understanding formation mechanisms for charged lepton spectrum and Majorana state we...

  3. Mass Spectrum and Number of Light Neutrinos: An Attempt of the Gauge Explanation

    E-Print Network [OSTI]

    I. T. Dyatlov

    2009-10-01T23:59:59.000Z

    Symplectic flavour symmetry group Sp(n/2) (n is even) of n Majorana states does not allow for invariant Majorana masses. Only specific mass matrices with diagonal and nondiagonal elements are possible here. As a result of the spontaneous violation of flavour and chiral symmetries, a mass matrix could appear only for the number of flavours n = 6 and only together with R,L-symmetry violation (i.e., parity violation). The see-saw mechanism produces here three light and three heavy Dirac particles (neutrinos). The peculiarity of the observed light neutrino spectrum: two states located far from the third one, can be explained by certain simple properties of mass matrices appearing in Sp(3). The ordering of the states corresponds to normal mass hierarchy. Situation, when neutrino mass differences are significantly less than masses themselves, appears to be unrealizable here. Mixing angles for neutrinos can not be determined without understanding formation mechanisms for charged lepton spectrum and Majorana state weak currents.

  4. Search for new physics in final states with a lepton and missing transverse energy in pp collisions at the LHC

    E-Print Network [OSTI]

    Apyan, Aram

    This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an ...

  5. Search for new physics in final states with a lepton and missing transverse energy in pp collisions at the LHC

    E-Print Network [OSTI]

    Baringer, Philip S.; Bean, Alice; Benelli, Gabriele; Kenny, R. P. III; Murray, Michael J.; Noonan, Danny; Sanders, Stephen J.; Stringer, Robert W.; Tinti, Gemma; Wood, Jeffrey Scott; Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.

    2013-04-08T23:59:59.000Z

    This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an ...

  6. Family number non-conservation induced by the supersymmetric mixing of scalar leptons

    SciTech Connect (OSTI)

    Levine, M.J.S.

    1987-08-01T23:59:59.000Z

    The most egregious aspect of (N = 1) supersymmetric theories is that each particle state is accompanied by a 'super-partner', a state with identical quantum numbers save that it differs in spin by one half unit. For the leptons these are scalars and are called ''sleptons'', or scalar leptons. These consist of the charged sleptons (selectron, smuon, stau) and the scalar neutrinos ('sneutrinos'). We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model. 49 refs., 12 figs.

  7. SU-4228-472 Simpson's Neutrino and the Singular See-Saw

    E-Print Network [OSTI]

    Allen, Theodore J.

    Burjassot, Val`encia, Spain Abstract We derive explicit forms for the neutrino and lepton "mixing-matrices neutrino in gauge theories is of the two-component "Majorana" type, it becomes a puzzle to understand why] on neutrinoless double beta decay (0). The only way out would be to have two Majorana neutrinos whose

  8. Leptons in Composite MFV

    E-Print Network [OSTI]

    Michele Redi

    2014-07-21T23:59:59.000Z

    We study the lepton sector of composite Higgs models with partial compositeness. The standard anarchic scenario is in conflict with the absence of observable charged lepton flavor violation. This tension can be completely solved in MFV scenarios that require either left-handed or right-handed SM leptons to be equally composite. Constraints on this scenario are weak and the composite lepton partners could be as light as few hundreds GeVs with interesting LHC signatures. The contribution to the muon (g-2) in theories where the Higgs is a pseudo Nambu-Goldstone boson is also discussed.

  9. Universal neutrino mass hierarchy and cosmological baryon number asymmetry

    SciTech Connect (OSTI)

    Xing Zhizhong [CCAST (World Laboratory), P.O. Box 8730, Beijing 100080 (China); Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918 (4), Beijing 100039 (China)

    2004-10-01T23:59:59.000Z

    We conjecture that three light Majorana neutrinos and their right-handed counterparts may have a universal geometric mass hierarchy. Incorporating this phenomenological conjecture with the Fritzsch texture of lepton mass matrices in a simple seesaw mechanism, we show that it is possible to simultaneously account for current neutrino oscillation data and the cosmological baryon number asymmetry via leptogenesis.

  10. Atmospheric Neutrinos

    E-Print Network [OSTI]

    Thomas K. Gaisser

    2006-12-11T23:59:59.000Z

    This paper is a brief overview of the theory and experimental data of atmospheric neutrino production at the fiftieth anniversary of the experimental discovery of neutrinos.

  11. Neutrino Physics

    E-Print Network [OSTI]

    Gil-Botella, I

    2013-01-01T23:59:59.000Z

    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.

  12. Big Bang Nucleosynthesis with Independent Neutrino Distribution Functions

    E-Print Network [OSTI]

    Christel J. Smith; George M. Fuller; Michael S. Smith

    2008-12-06T23:59:59.000Z

    We have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these distributions to the thermodynamics, the expansion rate and scale factor-time/temperature relationship, as well as to all relevant weak, electromagnetic, and strong nuclear reaction processes in the early universe. With this approach, we can treat any scenario in which neutrino or antineutrino spectral distortion might arise. These scenarios might include, for example, decaying particles, active-sterile neutrino oscillations, and active-active neutrino oscillations in the presence of significant lepton numbers. Our calculations allow lepton numbers and sterile neutrinos to be constrained with observationally-determined primordial helium and deuterium abundances. We have modified a standard BBN code to perform these calculations and have made it available to the community.

  13. Discriminating Majorana Neutrino Textures in the light of Baryon Asymmetry

    E-Print Network [OSTI]

    Borah, Manikanta; Das, Mrinal Kumar

    2015-01-01T23:59:59.000Z

    We study all possible texture zeros in the Majorana neutrino mass matrix which are allowed from neutrino oscillation as well as cosmology data when the charged lepton mass matrix is assumed to take the diagonal form. Considering two different possible values of the lightest neutrino mass giving rise to quasi-degenerate and hierarchical light neutrino mass spectrum respectively, we write down the Majorana CP phases as a function of the Dirac CP phase using the constraints coming from vanishing or equality of elements in a particular texture zero mass matrix. We constrain texture zero mass matrices from the requirement of producing correct baryon asymmetry through the mechanism of leptogenesis. Adopting a type I seesaw framework, we consider the CP violating out of equilibrium decay of the lightest right handed neutrino as the source of lepton asymmetry. Apart from discriminating between the texture zero mass matrices and light neutrino mass hierarchy, we also constrain the Dirac CP phase so that the observed b...

  14. Updated values of running quark and lepton masses at GUT scale in SM, 2HDM and MSSM

    E-Print Network [OSTI]

    Kalpana Bora

    2012-06-26T23:59:59.000Z

    Updated values of running quark and lepton masses at GUT (Grand unified theories) scales are important for fermion mass model building, and to calculate neutrino masses, in GUTs . We present their values at GUT scales, in SM, MSSM and 2HDM theories, using the latest values of running quark and lepton masses.

  15. DECAYS OF THE HEAVY LEPTON, TAU (1785)

    E-Print Network [OSTI]

    Blocker, Craig Alan

    2010-01-01T23:59:59.000Z

    G. S. Abrams et. a_K , PRL 4_3, 1555 (1979) W. Davies-WhiteL. v. C. Perl L. e t al_. , PRL 3 5 , al_. , et 63B, f,f^l. , Cavalli-Sforza J. Felinan PRL _3f r 558 H" (197

  16. Dirac Lepton Angle Matrix v.s. Majorana Lepton Angle Matrix and Their Renormalization Group Running Behaviours

    E-Print Network [OSTI]

    Shu Luo

    2011-12-14T23:59:59.000Z

    Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana neutrinos the RG-evolutions of Phi, Psi and the Jarlskog strongly depend on the Majorana-type CP-violating parameters and are quite sensitive to the sign of Delta m^{2}_{31}. They may receive significant radiative corrections in the MSSM if three neutrino masses are nearly degenerate.

  17. CP Violation in Neutrinoless Double Beta Decay and Neutrino Oscillation

    E-Print Network [OSTI]

    T. Fukuyama; K. Matsuda; H. Nishiura

    1998-03-03T23:59:59.000Z

    Taking account of possible CP violation, we discuss about the constraints on the lepton mixing angles from the neutrinoless double beta decay and from the neutrino oscillation for the three flavour Majorana neutrinos. From the CHORUS oscillation experiment, combined with the data of neutrinoless double beta decay, we show that the large angle solution of (\\theta_{23}) is improbable if the neutrino mass (m_3) of the third generation is a candidate of hot dark matters.

  18. Neutrino Mixing and Discrete Symmetries

    E-Print Network [OSTI]

    Hu, Bo

    2012-01-01T23:59:59.000Z

    A model independent study of neutrino mixing based on a new method to derive mixing patterns is presented. An interesting result we find is that, in the case where unbroken residual symmetries of the Majorana neutrino and left-handed charged-lepton mass matrices obey some general assumptions, the complete set of possible mixing patterns can be determined by the solutions to the constraint equation with the help of algebraic number theory. This method can also be applied to more general cases beyond the minimal scenario. Several applications and phenomenological implications are discussed.

  19. Muon Colliders and Neutrino Factories

    E-Print Network [OSTI]

    Daniel M. Kaplan; for the MAP; MICE Collaborations

    2014-12-10T23:59:59.000Z

    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.

  20. Muon Colliders and Neutrino Factories

    E-Print Network [OSTI]

    Kaplan, Daniel M

    2014-01-01T23:59:59.000Z

    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.

  1. Neutrino mass matrix

    SciTech Connect (OSTI)

    Capps, R.H.; Strobel, E.L.

    1985-07-01T23:59:59.000Z

    It is assumed that the Dirac mass matrix for the neutrinos (..nu../sub e/,..nu../sub ..mu../,..nu../sub tau/) is similar in form to those for the quarks and charged leptons, and that the smallness of the observed ..nu.. masses results from the Gell-Mann--Ramond--Slansky mechanism. It is shown that if certain tentative experimental results concerning the ..nu.. masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. Some general properties of the Dirac matrices are discussed.

  2. Electroweak model of lepton mass and mixing hierarchies

    E-Print Network [OSTI]

    E. M. Lipmanov

    2009-04-06T23:59:59.000Z

    Flavor physics, like cosmology, is likely in need of new basic ideas; the puzzles of elementary particle mass hierarchies and in particular the e-mu-tau and neutrino ones still remain mysteries. In this paper a new idea of dynamical connection between low energy 3-flavor particle mass hierarchies and electroweak charges is studied with restriction to the simplest case of lepton flavor phenomenology. The main inference is that it can be only two types of lepton 3-flavor particle-copy groups: 1) with large and strongly hierarchical mass ratios and 2) with close to 1 mass ratios. From experimental data definitely follows that the three charged leptons belong to the first type whereas the three neutrinos belong to the second type and so are quasi-degenerate. The inferences of QD-neutrinos with realistic small masses and oscillation hierarchy parameter and quark-QD-neutrino mixing angle complementarity follow from the fact of small EW charges and their relation to the concept of benchmark flavor pattern.

  3. Corrections to Scaling Neutrino Mixing: Non-zero $?_{13}, ?_{CP}$ and Baryon Asymmetry

    E-Print Network [OSTI]

    Rupam Kalita; Debasish Borah; Mrinal Kumar Das

    2015-03-11T23:59:59.000Z

    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 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.

  4. Statistical Understanding of Quark and Lepton Masses in Gaussian Landscapes

    E-Print Network [OSTI]

    Lawrence J. Hall; Michael P. Salem; Taizan Watari

    2007-08-10T23:59:59.000Z

    The fundamental theory of nature may allow a large landscape of vacua. Even if the theory contains a unified gauge symmetry, the 22 flavor parameters of the Standard Model, including neutrino masses, may be largely determined by the statistics of this landscape, and not by any symmetry. Then the measured values of the flavor parameters do not lead to any fundamental symmetries, but are statistical accidents; their precise values do not provide any insights into the fundamental theory, rather the overall pattern of flavor reflects the underlying landscape. We investigate whether random selection from the statistics of a simple landscape can explain the broad patterns of quark, charged lepton, and neutrino masses and mixings. We propose Gaussian landscapes as simplified models of landscapes where Yukawa couplings result from overlap integrals of zero-mode wavefunctions in higher-dimensional supersymmetric gauge theories. In terms of just five free parameters, such landscapes can account for all gross features of flavor, including: the hierarchy of quark and charged lepton masses; small quark mixing angles, with 13 mixing less than 12 and 23 mixing; very light Majorana neutrino masses, with the solar to atmospheric neutrino mass ratio consistent with data; distributions for leptonic 12 and 23 mixings that are peaked at large values, while the distribution for 13 mixing is peaked at low values; and order unity CP violating phases in both the quark and lepton sectors. While the statistical distributions for flavor parameters are broad, the distributions are robust to changes in the geometry of the extra dimensions. Constraining the distributions by loose cuts about observed values leads to narrower distributions for neutrino measurements of 13 mixing, CP violation, and neutrinoless double beta decay.

  5. Neutrinoless Double Beta Decay and Lepton Flavor Violation

    E-Print Network [OSTI]

    V. Cirigliano; A. Kurylov; M. J. Ramsey-Musolf; P. Vogel

    2004-06-17T23:59:59.000Z

    We point out that extensions of the Standard Model with low scale (~TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with GUT scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of \\mu -> e \\gamma and \\mu -> e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments.

  6. Texture-zero model for the lepton mass matrices

    E-Print Network [OSTI]

    Ferreira, P M

    2012-01-01T23:59:59.000Z

    We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and $M_{e\\mu} = 0$ ($M$ is the effective light-neutrino Majorana mass matrix). We show that these predictions perfectly agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if $m_3 = 0$, provided the Dirac phase $\\delta$ is very close to maximal ($\\pm \\pi / 2$). In the case of a normal neutrino mass spectrum, i.e. when $m_1 = 0$, the agreement of our model with the data is less than optimal---the reactor mixing angle $\\theta_{13}$ is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.

  7. Texture-zero model for the lepton mass matrices

    E-Print Network [OSTI]

    P. M. Ferreira; L. Lavoura

    2012-10-01T23:59:59.000Z

    We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and $M_{e\\mu} = 0$ ($M$ is the effective light-neutrino Majorana mass matrix). We show that these predictions perfectly agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if $m_3 = 0$, provided the Dirac phase $\\delta$ is very close to maximal ($\\pm \\pi / 2$). In the case of a normal neutrino mass spectrum, i.e. when $m_1 = 0$, the agreement of our model with the data is less than optimal---the reactor mixing angle $\\theta_{13}$ is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.

  8. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect (OSTI)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09T23:59:59.000Z

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and ?{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on ?{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  9. Neutrino Mass Matrix in Triplet Higgs Models with A-bar 4 Symmetry

    SciTech Connect (OSTI)

    Baek, Seungwon [Institute of Basic Science and Department of Physics, Korea University, Seoul (Korea, Republic of); Chu Oh, Myoung [Department of Physics, University of Seoul, Seoul (Korea, Republic of)

    2009-04-19T23:59:59.000Z

    The tribimaximal form of the neutrino mixing matrix can be naturally obtained with A-bar 4 flavor symmetry. We consider triplet Higgs model with A-bar 4 symmetry to generate the neutrino masses. With neutrino oscillation data we show that the mass matrix can be (almost) reconstructed, which allows us to predict the absolute neutrino mass scale including the neutrinoless double beta decay, the decay rates of the doubly charged Higgs boson to lepton pairs.

  10. Cosmological and supernova neutrinos

    SciTech Connect (OSTI)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Balantekin, A. B. [Department of Physics, University of Wisconsin - Madison, Wisconsin 53706 (United States); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Mathews, G. J. [Department of Physics, University of Notre Dame, IN 46556 (United States); Nakamura, K. [Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Pehlivan, Y. [Mimar Sinan GSÜ, Department of Physics, ?i?li, ?stanbul 34380 (Turkey); Suzuki, T. [Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-06-24T23:59:59.000Z

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on ?{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  11. Measurement of the ?[subscript e] and total [superscript 8]B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

    E-Print Network [OSTI]

    Formaggio, Joseph A.

    This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of [superscript 3]He proportional counters was installed in the heavy-water ...

  12. Textures for neutrino mass matrices

    SciTech Connect (OSTI)

    Leontaris, G.K.; Lola, S.; Scheich, C.; Vergados, J.D. [Theoretical Physics Division, Ioannina University, GR-45110 Ioannina (Greece)] [Theoretical Physics Division, Ioannina University, GR-45110 Ioannina (Greece); [Institut fuer Theoretische Physik, Univerisitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, 28049, Madrid (Spain); [Department of Natural Sciences, University of Cyprus, Nicosia (Cyprus)

    1996-06-01T23:59:59.000Z

    We give a classification of heavy Majorana neutrino mass matrices with up to three texture zeros, assuming the Dirac masses of the neutrinos to be of the same form as the ones of the up quarks in the five texture zero solutions for the quark matrices. This is the case for many unified and partially unified models. We find that it is possible to have solutions which account for the solar and atmospheric neutrino problems as well as the COBE observations simultaneously, and we motivate the existence of such solutions from symmetries. {copyright} {ital 1996 The American Physical Society.}

  13. Perturbations to $?-?$ Symmetry, Leptogenesis and Lepton Flavour Violation with Type II Seesaw

    E-Print Network [OSTI]

    Manikanta Borah; Debasish Borah; Mrinal Kumar Das; Sudhanwa Patra

    2014-10-17T23:59:59.000Z

    We study the possibility of generating non-zero reactor mixing angle $\\theta_{13}$ by perturbing the $\\mu-\\tau$ symmetric neutrino mass matrix. The leading order $\\mu-\\tau$ symmetric neutrino mass matrix originates from type I seesaw mechanism whereas the perturbations to $\\mu-\\tau$ symmetry originate from type II seesaw term. We consider four different realizations of $\\mu-\\tau$ symmetry: Bimaximal Mixing(BM), Tri-bimaximal Mixing (TBM), Hexagonal Mixing (HM) and Golden Ratio Mixing (GRM) all giving rise to $\\theta_{13} = 0, \\theta_{23} = \\frac{\\pi}{4}$ but different non-zero values of solar mixing angle $\\theta_{12}$. We assume a minimal $\\mu-\\tau$ symmetry breaking type II seesaw mass matrix as a perturbation and calculate the neutrino oscillation parameters as a function of type II seesaw strength. We then consider the origin of non-trivial leptonic CP phase in the charged lepton sector and calculate the lepton asymmetry arising from the lightest right handed neutrino decay by incorporating the presence of both type I and type II seesaw. We constrain the type II seesaw strength as well as leptonic CP phase (and hence the charged lepton sector) by comparing our results with experimental neutrino oscillation parameters as well as Planck bound on baryon to photon ratio. Finally, we extend our analysis on lepton flavour violating decays like $\\mu \\to e \\gamma$ and $\\mu \\to eee$ due to exchange of TeV scale Higgs triplet scalar within the low scale type II seesaw framework. The branching ratios for these lepton flavour processes are examined with the small type II perturbation term $\\omega$ and the estimated values are very close to the experimental bound coming from current search experiments.

  14. Near Detectors for a Neutrino Factory

    SciTech Connect (OSTI)

    Morfin, Jorge G. [Fermi National Accelerator Laboratory (United States)

    2011-11-23T23:59:59.000Z

    The baseline design for a Neutrino Factory includes the need for one or more near detectors.The near detectors must be designed to carry out measurements essential to the sensitivity of the oscillation-physics program. In addition, the intense neutrino beam delivered by the Neutrino Factory makes it possible to carry out a unique neutrino-physics program at the near detectors. This program includes fundamental electroweak and QCD physics. The near detector must also be capable of searching for new physics, for example by detecting tau-leptons which are particularly sensitive probes of non-standard interactions at source and at detection. This paper is extracted from the Near Detector chapter of the Neutrino Factory Interim Design Report.

  15. Neutrino Mixing

    E-Print Network [OSTI]

    Carlo Giunti; Marco Laveder

    2004-10-01T23:59:59.000Z

    In this review we present the main features of the current status of neutrino physics. After a review of the theory of neutrino mixing and oscillations, we discuss the current status of solar and atmospheric neutrino oscillation experiments. We show that the current data can be nicely accommodated in the framework of three-neutrino mixing. We discuss also the problem of the determination of the absolute neutrino mass scale through Tritium beta-decay experiments and astrophysical observations, and the exploration of the Majorana nature of massive neutrinos through neutrinoless double-beta decay experiments. Finally, future prospects are briefly discussed.

  16. Lepton Flavor Violation in Flavored Gauge Mediation

    E-Print Network [OSTI]

    Lorenzo Calibbi; Paride Paradisi; Robert Ziegler

    2014-08-04T23:59:59.000Z

    We study the anatomy and phenomenology of Lepton Flavor Violation (LFV) in the context of Flavored Gauge Mediation (FGM). Within FGM, the messenger sector couples directly to the MSSM matter fields with couplings controlled by the same dynamics that explains the hierarchies in the SM Yukawas. Although the pattern of flavor violation depends on the particular underlying flavor model, FGM provides a built-in flavor suppression similar to wave function renormalization or SUSY Partial Compositeness. Moreover, in contrast to these models, there is an additional suppression of left-right (LR) flavor transitions by third-generation Yukawas that in particular provides an extra protection against flavor-blind phases. We exploit the consequences of this setup for lepton flavor phenomenology, assuming that the new couplings are controlled by simple U(1) flavor models that have been proposed to accommodate large neutrino mixing angles. Remarkably, it turns out that in the context of FGM these models can pass the impressive constraints from LFV processes and leptonic EDMs even for light superpartners, therefore offering the possibility of resolving the longstanding muon g-2 anomaly.

  17. Quark-lepton symmetric model at the LHC

    E-Print Network [OSTI]

    Jackson D. Clarke; Robert Foot; Raymond R. Volkas

    2012-02-04T23:59:59.000Z

    We investigate the quark-lepton symmetric model of Foot and Lew in the context of the Large Hadron Collider (LHC). In this `bottom-up' extension to the Standard Model, quark-lepton symmetry is achieved by introducing a gauged `leptonic colour' symmetry which is spontaneously broken above the electroweak scale. If this breaking occurs at the TeV scale, then we expect new physics to be discovered at the LHC. We examine three areas of interest: the Z$'$ heavy neutral gauge boson, charge $\\pm1/2$ exotic leptons, and a colour triplet scalar diquark. We find that the LHC has already explored and/or will explore new parameter space for these particles over the course of its lifetime.

  18. Neutrinos in Physics and Astrophysics

    E-Print Network [OSTI]

    G. G. Raffelt

    2003-03-05T23:59:59.000Z

    The observed flavor oscillations of solar and atmospheric neutrinos determine several elements of the leptonic mixing matrix, but leave open the small mixing angle Theta_13, a possible CP-violating phase, the mass ordering, the absolute mass scale m_nu, and the Dirac vs. Majorana property. Progress will be made by long-baseline, tritium endpoint, and 2-beta decay experiments. The best constraint on m_nu obtains from cosmological precision observables, implying that neutrinos contribute very little to the dark matter. However, massive Majorana neutrinos may well be responsible for ordinary matter by virtue of the leptogenesis mechanism for creating the baryon asymmetry of the universe. In future, neutrinos could play an important role as astrophysical messengers if point sources are discovered in high-energy neutrino telescopes. In the low-energy range, a high-statistics observation of a galactic supernova would allow one to observe directly the dynamics of stellar collapse and perhaps to discriminate between certain mixing scenarios. An observation of the relic neutrinos from all past supernovae has come within reach.

  19. Study of top quark production and decays involving a tau lepton at CDF and limits on a charged Higgs boson contribution

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We present an analysis of top-antitop quark production and decay into a tau lepton, tau neutrino, and bottom quark using data from 9??fb[superscript ?1] of integrated luminosity at the Collider Detector at Fermilab. Dilepton ...

  20. Texture Zero Mass Matrices and Flavor Mixing of Quarks and Leptons

    E-Print Network [OSTI]

    Fritzsch, Harald

    2015-01-01T23:59:59.000Z

    We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: $m_1$ $\\approx$ 0.003 eV , $m_2$ $\\approx$ 0.012 eV , $m_3$ $\\approx$ 0.048 eV.

  1. Probing the Majorana nature of the neutrino with neutrinoless double beta decay

    E-Print Network [OSTI]

    S. Morisi

    2009-10-14T23:59:59.000Z

    Neutrinoless double beta decay (NDBD) is the only experiment that could probe the Majorana nature of the neutrino. Here we study the theoretical implications of NDBD for models yielding tri-bimaximal lepton mixing like A4 and S4.

  2. Neutrino Factories

    SciTech Connect (OSTI)

    Geer, Steve; /Fermilab

    2010-01-01T23:59:59.000Z

    Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture and accelerate O(10{sup 21}) muons/year. This prepares the way for a Neutrino Factory (NF) in which high energy muons decay within the straight sections of a storage ring to produce a beam of neutrinos and anti-neutrinos. The NF concept was proposed in 1997 at a time when the discovery that the three known types of neutrino ({nu}{sub e}, {nu}{sub {mu}}, {nu}{sub {tau}}) can change their flavor as they propagate through space (neutrino oscillations) was providing a first glimpse of physics beyond the Standard Model. This development prepares the way for a new type of neutrino source: a Neutrino Factory. This article reviews the motivation, design and R&D for a Neutrino Factory.

  3. Minimal archi-texture for neutrino mass matrices

    E-Print Network [OSTI]

    Atsushi Watanabe; Koichi Yoshioka

    2006-03-15T23:59:59.000Z

    The origin of the observed masses and mixing angles of quarks and leptons is one of imperative subjects in and beyond the standard model. Toward a deeper understanding of flavor structure, we investigate in this paper the minimality of fermion mass (Yukawa) matrices in unified theory. That is, the simplest matrix form is explored in light of the current experimental data for quarks and leptons, including the recent measurements of quark CP violation and neutrino oscillations. Two types of neutrino mass schemes are particularly analyzed; (i) Majorana masses of left-handed neutrinos with unspecified mechanism and (ii) Dirac and Majorana masses introducing three right-handed neutrinos. As a result, new classes of neutrino mass matrices are found to be consistent to the low-energy experimental data and high-energy unification hypothesis. For distinctive phenomenological implications of the minimal fermion mass textures, we discuss flavor-violating decay of charged leptons, the baryon asymmetry of the universe via thermal leptogenesis, neutrino-less double beta decay, and low-energy leptonic CP violation.

  4. On-shell renormalization of the mixing matrices in Majorana neutrino theories

    E-Print Network [OSTI]

    Andrea A. Almasy; Bernd A. Kniehl; Alberto Sirlin

    2009-04-20T23:59:59.000Z

    We generalize a recently proposed on-shell approach to renormalize the Cabibbo-Kobayashi-Maskawa quark-mixing matrix to the case of an extended leptonic sector that includes Dirac and Majorana neutrinos in the framework of the seesaw mechanism. An important property of this formulation is the gauge independence of both the renormalized and bare lepton mixing matrices. Also, the texture zero in the neutrino mass matrix is preserved.

  5. Evidence for Neutrino Oscillations I: Solar and Reactor Neutrinos

    E-Print Network [OSTI]

    A. B. McDonald

    2004-12-06T23:59:59.000Z

    This paper discusses evidence for neutrino oscillations obtained from measurements with solar neutrinos and reactor neutrinos.

  6. Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II

    E-Print Network [OSTI]

    Mitsuka, G; Hayato, Y; Iida, T; Ikeda, M; Kameda, J; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Hazama, S; Higuchi, I; Ishihara, C; Kaji, H; Kajita, T; Kaneyuki, K; Nishino, H; Okumura, K; Tanimoto, N; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Bays, K; Cravens, J P; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Vagins, M R; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J; Scholberg, K; Walter, C W; Wendell, R; Ishizuka, T; Tasaka, S; Learned, J G; Matsuno, S; Watanabe, Y; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Yokoyama, M; Fukuda, Y; Itow, Y; Tanaka, T; Jung, C K; Lopez, G; McGrew, C; Yanagisawa, C; Tamura, N; Idehara, Y; Sakuda, M; Kuno, Y; Yoshida, M; Kim, S B; Yang, B S; Okazawa, H; Choi, Y; Seo, H K; Furuse, Y; Nishijima, K; Yokosawa, Y; Koshiba, M; Totsuka, Y; Chen, S; Liu, J; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Connolly, K; Thrane, E; Wilkes, R J

    2011-01-01T23:59:59.000Z

    In this paper we study non-standard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton non-universality (NU) and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|Super-Kamiokande atmospheric data.

  7. Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II

    E-Print Network [OSTI]

    G. Mitsuka; K. Abe; Y. Hayato; T. Iida; M. Ikeda; J. Kameda; Y. Koshio; M. Miura; S. Moriyama; M. Nakahata; S. Nakayama; Y. Obayashi; H. Sekiya; M. Shiozawa; Y. Suzuki; A. Takeda; Y. Takenaga; Y. Takeuchi; K. Ueno; K. Ueshima; H. Watanabe; S. Yamada; S. Hazama; I. Higuchi; C. Ishihara; H. Kaji; T. Kajita; K. Kaneyuki; H. Nishino; K. Okumura; N. Tanimoto; F. Dufour; E. Kearns; M. Litos; J. L. Raaf; J. L. Stone; L. R. Sulak; M. Goldhaber; K. Bays; J. P. Cravens; W. R. Kropp; S. Mine; C. Regis; M. B. Smy; H. W. Sobel; M. R. Vagins; K. S. Ganezer; J. Hill; W. E. Keig; J. S. Jang; J. Y. Kim; I. T. Lim; J. Albert; K. Scholberg; C. W. Walter; R. Wendell; T. Ishizuka; S. Tasaka; J. G. Learned; S. Matsuno; Y. Watanabe; T. Hasegawa; T. Ishida; T. Ishii; T. Kobayashi; T. Nakadaira; K. Nakamura; K. Nishikawa; Y. Oyama; K. Sakashita; T. Sekiguchi; T. Tsukamoto; A. T. Suzuki; A. Minamino; T. Nakaya; M. Yokoyama; Y. Fukuda; Y. Itow; T. Tanaka; C. K. Jung; G. Lopez; C. McGrew; C. Yanagisawa; N. Tamura; Y. Idehara; M. Sakuda; Y. Kuno; M. Yoshida; S. B. Kim; B. S. Yang; H. Okazawa; Y. Choi; H. K. Seo; Y. Furuse; K. Nishijima; Y. Yokosawa; M. Koshiba; Y. Totsuka; S. Chen; J. Liu; Y. Heng; Z. Yang; H. Zhang; D. Kielczewska; K. Connolly; E. Thrane; R. J. Wilkes

    2011-09-09T23:59:59.000Z

    In this paper we study non-standard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton non-universality (NU) and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|Super-Kamiokande atmospheric data.

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

    E-Print Network [OSTI]

    Zachary Marshall; Burt A. Ovrut; Austin Purves; Sogee Spinner

    2014-08-05T23:59:59.000Z

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

  9. Top Quark Mass in Events with two Charged Leptons at the D0 Experiment

    SciTech Connect (OSTI)

    Boline, Daniel Dooley; /Boston U.

    2010-01-01T23:59:59.000Z

    The top quark is the most massive observed fundamental subatomic particle, and at the Tevatron accelerator is produced mostly in top-antitop (t{bar t}) quark pairs from the collisions of protons and anti-protons. Each top quark decays into a bottom quark and a W boson. The W boson can then decay into a pair of quarks, or into a charged lepton and a neutrino. The various decays can be broken up into three different channels based on the number of leptons from the decay of the W bosons: all-jets (with no leptons), lepton+jets (with one lepton), and dilepton (with two leptons). This dissertation will present a measurement of the top quark mass in the dilepton channel. The dilepton channel is characterized by two leptons, two neutrinos and two b-quarks. The neutrinos are not directly observed, but their absence is felt as missing transverse momentum (p{sub T}) in the detector. The combination of two leptons and large p{sub T} produces an easily isolated signal, giving the dilepton channel a high signal over background ratio. Having two neutrinos means that we cannot know what the transverse momenta of either neutrino is. This means that even if we knew the momenta of the leptons and b-quarks perfectly, we would be unable to reconstruct the mass of the top quark. This measurement gets around this problem by scanning over all possible values of the top mass, finding all consistent t{bar t} combinations, assigning a kinematic weight to each, and then adding the weights for each combination at a given possible top mass. The lepton momenta, jet momenta, and p{sub T} are only known to within some finite precision, so for a given top mass, I also vary each of these momenta within their resolutions and add the weights for a given possible top mass. After scanning over possible top masses, I choose the top mass with the largest sum of weights m{sub t}{sup max} as an observable for the event. I then perform a template based likelihood fit of m{sub t} using m{sub t}{sup max}. I analyze 322 candidate events collected by the D0 detector, and obtain a top quark mass of: m{sub t} = 174.8 {+-} 3.1 GeV.

  10. Dirac Lepton Angle Matrix v.s. Majorana Lepton Angle Matrix and Their Renormalization Group Running Behaviours

    E-Print Network [OSTI]

    Luo, Shu

    2011-01-01T23:59:59.000Z

    Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana ne...

  11. Light Sterile Neutrinos and Short Baseline Neutrino Oscillation Anomalies

    E-Print Network [OSTI]

    JiJi Fan; Paul Langacker

    2012-01-31T23:59:59.000Z

    We study two possible explanations for short baseline neutrino oscillation anomalies, such as the LSND and MiniBooNE anti-neutrino data, and for the reactor anomaly. The first scenario is the mini-seesaw mechanism with two eV-scale sterile neutrinos. We present both analytic formulas and numerical results showing that this scenario could account for the short baseline and reactor anomalies and is consistent with the observed masses and mixings of the three active neutrinos. We also show that this scenario could arise naturally from an effective theory containing a TeV-scale VEV, which could be related to other TeV-scale physics. The minimal version of the mini-seesaw relates the active-sterile mixings to five real parameters and favors an inverted hierarchy. It has the interesting property that the effective Majorana mass for neutrinoless double beta decay vanishes, while the effective masses relevant to tritium beta decay and to cosmology are respectively around 0.2 and 2.4 eV. The second scenario contains only one eV-scale sterile neutrino but with an effective non-unitary mixing matrix between the light sterile and active neutrinos. We find that though this may explain the anomalies, if the non-unitarity originates from a heavy sterile neutrino with a large (fine-tuned) mixing angle, this scenario is highly constrained by cosmological and laboratory observations.

  12. Neutrino Mixing and Masses from a Minimum Principle

    E-Print Network [OSTI]

    Alonso, R; Isidori, G; Maiani, L

    2013-01-01T23:59:59.000Z

    We analyze the structure of quark and lepton mass matrices under the hypothesis that they are determined from a minimum principle applied to a generic potential invariant under the $[SU(3)]^5\\otimes {\\mathcal O}(3)$ flavor symmetry, acting on Standard Model fermions and right-handed neutrinos. Unlike the quark case, we show that hierarchical masses for charged leptons are naturally accompanied by degenerate Majorana neutrinos with one angle close to maximal, a second potentially large, a third one necessarily small, and precise values for the two Majorana phases. Adding small perturbations the predicted structure for the neutrino mass matrix is in excellent agreement with present observations and could be tested in the near future via neutrino-less double beta decay. The generalization of these results to arbitrary sew-saw models is also discussed.

  13. Neutrino Decay and Neutrinoless Double Beta Decay in a 3-3-1 Model

    E-Print Network [OSTI]

    Alex G. Dias; A. Doff; C. A. de S. Pires; P. S. Rodrigues da Silva

    2005-08-11T23:59:59.000Z

    In this work we show that the implementation of spontaneous breaking of the lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast neutrino decay with majoron emission and generates a bunch of new contributions to the neutrinoless double beta decay.

  14. Neutrino decay and neutrinoless double beta decay in a 3-3-1 model

    SciTech Connect (OSTI)

    Dias, Alex G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66.318, 05315-970, Sao Paulo-SP (Brazil); Doff, A. [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900 Sao Paulo-SP (Brazil); Pires, C.A. de S; Rodrigues da Silva, P.S. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970, Joao Pessoa-PB (Brazil)

    2005-08-01T23:59:59.000Z

    In this work we show that the implementation of spontaneous breaking of the lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast neutrino decay with Majoron emission and generates a bunch of new contributions to the neutrinoless double beta decay.

  15. Attempt at a gauge-theory-based explanation of the mass spectrum and number of light neutrinos

    SciTech Connect (OSTI)

    Dyatlov, I. T. [Russian Academy of Sciences, Petersburg Nuclear Physics Institute (Russian Federation)

    2009-12-15T23:59:59.000Z

    The symplectic group Sp(n/2) of invariance of flavors of n Majorana states (n is even) does not admit the existence of invariant Majorana masses. Only a specific mass matrix involving diagonal and off-diagonal elements is possible. A mass matrix as a result of spontaneous flavor- and chiral-symmetry breaking may appear here only in the case where the number of flavors is n = 6 and only together with spontaneous R- and L-symmetry violation-that is, parity violation. As a result, three light and three heavy Dirac particles (neutrinos) are present if the seesaw mechanism is operative. Special features of the observed spectrum of light neutrinos-in particular, the fact that two states are far off the third one-can be explained by simple properties of the mass matrices arising in Sp(3). The arrangement of states corresponds to an ordinary mass hierarchy. The mixing angles for physical neutrinos cannot be determined without understanding the mechanisms responsible for the formation of the charged-lepton spectrum and the weak current of Majorana states.

  16. Neutrino oscillation constraints on neutrinoless double beta decay

    E-Print Network [OSTI]

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

    1997-11-20T23:59:59.000Z

    We have studied the constraints imposed by the results of neutrino oscillation experiments on the effective Majorana mass || that characterizes the contribution of Majorana neutrino masses to the matrix element of neutrinoless double-beta decay. We have shown that in a general scheme with three Majorana neutrinos and a hierarchy of neutrino masses (which can be explained by the see-saw mechanism), the results of neutrino oscillation experiments imply rather strong constraints on the parameter ||. From the results of the first reactor long-baseline experiment CHOOZ and the Bugey experiment it follows that || | > 10^{-1} eV would be a signal for a non-hierarchical neutrino mass spectrum and/or non-standard mechanisms of lepton number violation.

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

    E-Print Network [OSTI]

    Yuta Hamada; Tatsuo Kobayashi; Shohei Uemura

    2014-06-11T23:59:59.000Z

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

  18. Fermi-Boltzmann statistics of neutrinos and relativistic effective degrees of freedom

    E-Print Network [OSTI]

    Jun Iizuka; Teruyuki Kitabayashi

    2014-11-22T23:59:59.000Z

    We investigate the effect of the presence of non-pure fermionic neutrinos on the relativistic effective degrees of freedom in the early universe. The statistics of neutrinos is transformed continuously from Fermi-Dirac to Maxwell-Boltzmann statistics. We find that the relativistic degrees of freedom decreases with the deviation from pure Fermi-Dirac statistics of neutrinos if there are constant and large lepton asymmetries. Additionally, we confirm that the change of the statistics of neutrinos from Fermi-Dirac to Maxwell-Boltzmann is not sufficient to cover the excess of the effective number of neutrinos.

  19. Anomalous magnetic and electric moments of $?$ and lepton flavor mixing matrix in effective lagrangian approach

    E-Print Network [OSTI]

    J. Q. Zhang; X. C. Song; W. J. Huo; T. F. Feng

    2002-06-17T23:59:59.000Z

    In an effective lagrangian approach [EM97] to new physics, the authors in ref. [HL99] pushed tau anomalous magnetic and electric dipole moments (AMDM and EDM) down to $10^{-11}$ and $10^{-25} e cm$ by using a Fritzsch-Xing lepton mass matrix ansatz. In this note, we find that, in this approach, there exists the connection between $\\tau$ AMDM and EDM and the lepton flavor mixing matrix. By using the current neutrino oscillation experimental results, we investigate the parameter space of lepton mixing angles to $\\tau$ AMDM and EDM. We can obtain the same or smaller bounds of $\\delta a_\\tau$ and $d_\\tau$ acquired in ref. [HL99] and constrain $\\theta_l$ (the mixing angle obtained by long-baseline neutrino oscillation experiments) from $\\tau$ AMDM and EDM.

  20. Neutrino oscillations in the early Universe

    E-Print Network [OSTI]

    D. Kirilova; M. Chizhov

    2001-02-09T23:59:59.000Z

    We discuss the oscillations effects on neutrinos in the early Universe and update the cosmological constraints on the oscillation parameters. It is shown that sterile LOW solution to the solar neutrino problem is almost completely excluded from cosmological nucleosynthesis considerations. Two possibilities for the relaxation of this constraint are discussed: high primordial helium-4 yield and a relic lepton asymmetry present at nucleosynthesis epoch. The numerical analysis proved that Y_p=0.25 only relaxes the constraint on LOW solution, while L > 10^{-5} is capable to remove it.

  1. Neutrinoless Double Beta Decay and Neutrino Masses

    E-Print Network [OSTI]

    Michael Duerr

    2012-06-04T23:59:59.000Z

    Neutrinoless double beta decay is a promising test for lepton number violating physics beyond the standard model of particle physics. There is a deep connection between this decay and the phenomenon of neutrino masses. In particular, we will discuss the relation between neutrinoless double beta decay and Majorana neutrino masses provided by the so-called Schechter--Valle theorem in a quantitative way. Furthermore, we will present an experimental cross check to discriminate neutrinoless double beta decay from unknown nuclear background using only one isotope, i.e., within one experiment.

  2. Neutrinoless double beta decay and neutrino masses

    SciTech Connect (OSTI)

    Duerr, Michael [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2012-07-27T23:59:59.000Z

    Neutrinoless double beta decay (0{nu}{beta}{beta}) is a promising test for lepton number violating physics beyond the standard model (SM) of particle physics. There is a deep connection between this decay and the phenomenon of neutrino masses. In particular, we will discuss the relation between 0{nu}{beta}{beta} and Majorana neutrino masses provided by the so-called Schechter-Valle theorem in a quantitative way. Furthermore, we will present an experimental cross check to discriminate 0{nu}{beta}{beta} from unknown nuclear background using only one isotope, i.e., within one experiment.

  3. An SO(10) GUT Model With Lopsided Mass Matrix and Neutrino Mixing Angle theta_13

    E-Print Network [OSTI]

    Xiangdong Ji; Yingchuan Li; R. N. Mohapatra

    2005-10-27T23:59:59.000Z

    An alternative supersymmetric SO(10) grand unification model with lopsided fermion mass matrices is introduced. It generates a large solar-neutrino-mixing angle through the neutrinos' Dirac mass matrix constrained by the SO(10) group structure, avoiding the fine-tuning required in the Majorana mass matrix of right-handed neutrinos. The model fits well the known data on masses and mixings of quarks and leptons, and predicts a sizable lepton mixing $\\sin^22\\theta_{13}\\simeq 0.074$, which is significantly larger than that of the original lopsided model.

  4. Neutrino masses and solar neutrinos

    SciTech Connect (OSTI)

    Wolfenstein, L.

    1992-01-01T23:59:59.000Z

    It has been pointed out by Bahcall and Bethe and others that all solar neutrino data can be explained by MSW oscillations with m([nu][sub [mu

  5. Neutrino masses from U(1) symmetries and the Super-Kamiokande data

    E-Print Network [OSTI]

    Smaragda Lola; Graham G. Ross

    1999-02-09T23:59:59.000Z

    Motivated by the Super-Kamiokande data, we revisit models with U(1) symmetries and discuss the origin of neutrino masses and mixings in such theories. We show that, in models with just three light neutrinos and a hierarchy of neutrino masses, large (2-3) mixing fixes the lepton doublet U(1) charges and is thus related to the structure of the charged lepton mass matrix. We discuss the fermion mass structure that follows from the Abelian family symmetry with an extended gauge group. Requiring that the quark and lepton masses be ordered by the family symmetry, we identify the most promising scheme. This requires large, but not necessarily maximal, mixing in the mu-tau sector and gives small e-mu mixing in the range that is required for the small angle solution of the solar neutrino deficit.

  6. Neutrinoless Double Beta Decay in Heavy Deformed Nuclei

    E-Print Network [OSTI]

    Jorge G. Hirsch; O. Castańos; P. O. Hess

    1994-07-12T23:59:59.000Z

    The zero neutrino mode of the double beta decay in heavy deformed nuclei is investigated in the framework of the pseudo SU(3) model, which has provided an accurate description of collective nuclear structure and predicted half-lives for the two neutrino mode in good agreement with experiments. In the case of $^{238}U$ the calculated zero neutrino half-life is at least three orders of magnitude greater than the two neutrino one, giving strong support of the identification of the radiochemically determined half-life as being the two neutrino double beta decay. For $^{150}Nd$ the zero neutrino matrix elements are of the order of magnitude of, but lesser than, those evaluated using the QRPA. This result confirms that different nuclear models produce similar zero neutrino matrix elements, contrary to the two neutrino case. Using these pseudo SU(3) results and the upper limit for the neutrino mass we estimate the $\\beta\\beta_{0\

  7. Impact of Lepton Number Violation at the LHC on Models of Leptogenesis

    E-Print Network [OSTI]

    Frank F. Deppisch; Julia Harz

    2014-08-22T23:59:59.000Z

    The discovery of lepton number violation (LNV) at the LHC would have profound consequences for the viability of high-scale leptogenesis models. As an example, we discuss the case of observing a signal with two same-sign leptons, two jets and no missing energy. This would imply a large washout factor for the lepton number density in the early Universe, which leads to a significant constraint on any high-scale model for the generation of the observed baryon asymmetry. In a standard leptogenesis scenario, the corresponding washout factor would strongly decrease a pre-existing lepton asymmetry and thus would render leptogenesis models that generate a (B-L) asymmetry far above the LHC scale ineffective. Therefore, LHC searches focused on LNV processes without missing energy are powerful probes for high-scale leptogenesis models and correspondingly shed light on the nature of baryogenesis and neutrino masses.

  8. Using Neutrino Nucleus Interactions as a Probe of the Strong Interaction

    SciTech Connect (OSTI)

    Morfin, Jorge G. [Fermi National Accelerator Laboratory (United States)

    2011-11-23T23:59:59.000Z

    Neutrino scattering experiments have been studying QCD for over 30 years. From the Gargamelle experiments in the early 70's, through the subsequent bubble chamber and electronic detector experiments in the 80's and 90's, neutrino scattering experiments have steadily accumulated increasing statistics and minimized their systematic errors. An example of the more recent studies of QCD with neutrinos is from the TeVatron neutrino beam--the NuTeV {nu}-Fe experiment. The problem the community faces in trying to study QCD with modern neutrino data is that there is no experimentally verified way to scale neutrino-nucleus (for example, Fe) results to the equivalent neutrino-nucleon values making it difficult to combine neutrino nucleus scattering data with charged-lepton nucleus and nucleon scattering data in QCD global fits to extract parton distribution functions. This is particularly crucial since there is now indications that nuclear effects in neutrino nucleus interactions are different than those measured in charged-lepton nucleus scattering. To better understand this situation, the MINER{nu}A neutrino-nucleus scattering experiment at Fermilab, a collaboration of elementary-particle and nuclear physicists, is systematically studying neutrino nuclear effects off of He, C, Fe and Pb for a more thorough A-dependent study of nuclear PDFs and these correction factors.

  9. A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

    E-Print Network [OSTI]

    :,; Aihara, H; Andreopoulos, C; Anghel, I; Ariga, A; Ariga, T; Asfandiyarov, R; Askins, M; Back, J J; Ballett, P; Barbi, M; Barker, G J; Barr, G; Bay, F; Beltrame, P; Berardi, V; Bergevin, M; Berkman, S; Berry, T; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bolognesi, S; Boyd, S B; Bravar, A; Bronner, C; Cafagna, F S; Carminati, G; Cartwright, S L; Catanesi, M G; Choi, K; Choi, J H; Collazuol, G; Cowan, G; Cremonesi, L; Davies, G; De Rosa, G; Densham, C; Detwiler, J; Dewhurst, D; Di Lodovico, F; Di Luise, S; Drapier, O; Emery, S; Ereditato, A; Fernandez, P; Feusels, T; Finch, A; Fitton, M; Friend, M; Fujii, Y; Fukuda, Y; Fukuda, D; Galymov, V; Ganezer, K; Gonin, M; Gumplinger, P; Hadley, D R; Haegel, L; Haesler, A; Haga, Y; Hartfiel, B; Hartz, M; Hayato, Y; Hierholzer, M; Hill, J; Himmel, A; Hirota, S; Horiuchi, S; Huang, K; Ichikawa, A K; Iijima, T; Ikeda, M; Imber, J; Inoue, K; Insler, J; Intonti, R A; Irvine, T; Ishida, T; Ishino, H; Ishitsuka, M; Itow, Y; Izmaylov, A; Jamieson, B; Jang, H I; Jiang, M; Joo, K K; Jung, C K; Kaboth, A; Kajita, T; Kameda, J; Karadhzov, Y; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kim, J Y; Kim, S B; Kishimoto, Y; Kobayashi, T; Koga, M; Konaka, A; Kormos, L L; Korzenev, A; Koshio, Y; Kropp, W R; Kudenko, Y; Kutter, T; Kuze, M; Labarga, L; Lagoda, J; Laveder, M; Lawe, M; Learned, J G; Lim, I T; Lindner, T; Longhin, A; Ludovici, L; Ma, W; Magaletti, L; Mahn, K; Malek, M; Mariani, C; Marti, L; Martin, J F; Martin, C; Martins, P P J; Mazzucato, E; McCauley, N; McFarland, K S; McGrew, C; Mezzetto, M; Minakata, H; Minamino, A; Mine, S; Mineev, O; Miura, M; Monroe, J; Mori, T; Moriyama, S; Mueller, T; Muheim, F; Nakahata, M; Nakamura, K; Nakaya, T; Nakayama, S; Needham, M; Nicholls, T; Nirkko, M; Nishimura, Y; Noah, E; Nowak, J; Nunokawa, H; O'Keeffe, H M; Okajima, Y; Okumura, K; Oser, S M; O'Sullivan, E; Owen, R A; Oyama, Y; Perez, J; Pac, M Y; Palladino, V; Palomino, J L; Paolone, V; Payne, D; Perevozchikov, O; Perkin, J D; Pistillo, C; Playfer, S; Posiadala-Zezula, M; Poutissou, J -M; Quilain, B; Quinto, M; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M; Redij, A; Retiere, F; Riccio, C; Richard, E; Rondio, E; Rose, H J; Ross-Lonergan, M; Rott, C; Rountree, S D; Rubbia, A; Sacco, R; Sakuda, M; Sanchez, M C; Scantamburlo, E; Scholberg, K; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Shaikhiev, A; Shimizu, I; Shiozawa, M; Short, S; Sinnis, G; Smy, M B; Sobczyk, J; Sobel, H W; Stewart, T; Stone, J L; Suda, Y; Suzuki, Y; Suzuki, A T; Svoboda, R; Tacik, R; Takeda, A; Taketa, A; Takeuchi, Y; Tanaka, H A; Tanaka, H K M; Tanaka, H; Terri, R; Thompson, L F; Thorpe, M; Tobayama, S; Tolich, N; Tomura, T; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vagins, M R; Vasseur, G; Vogelaar, R B; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilson, J R; Xin, T; Yamamoto, K; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Zito, M

    2014-01-01T23:59:59.000Z

    Hyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of $CP$ asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hep-ex

  10. A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

    E-Print Network [OSTI]

    Hyper-Kamiokande Working Group; :; K. Abe; H. Aihara; C. Andreopoulos; I. Anghel; A. Ariga; T. Ariga; R. Asfandiyarov; M. Askins; J. J. Back; P. Ballett; M. Barbi; G. J. Barker; G. Barr; F. Bay; P. Beltrame; V. Berardi; M. Bergevin; S. Berkman; T. Berry; S. Bhadra; F. d. M. Blaszczyk; A. Blondel; S. Bolognesi; S. B. Boyd; A. Bravar; C. Bronner; F. S. Cafagna; G. Carminati; S. L. Cartwright; M. G. Catanesi; K. Choi; J. H. Choi; G. Collazuol; G. Cowan; L. Cremonesi; G. Davies; G. De Rosa; C. Densham; J. Detwiler; D. Dewhurst; F. Di Lodovico; S. Di Luise; O. Drapier; S. Emery; A. Ereditato; P. Fernandez; T. Feusels; A. Finch; M. Fitton; M. Friend; Y. Fujii; Y. Fukuda; D. Fukuda; V. Galymov; K. Ganezer; M. Gonin; P. Gumplinger; D. R. Hadley; L. Haegel; A. Haesler; Y. Haga; B. Hartfiel; M. Hartz; Y. Hayato; M. Hierholzer; J. Hill; A. Himmel; S. Hirota; S. Horiuchi; K. Huang; A. K. Ichikawa; T. Iijima; M. Ikeda; J. Imber; K. Inoue; J. Insler; R. A. Intonti; T. Irvine; T. Ishida; H. Ishino; M. Ishitsuka; Y. Itow; A. Izmaylov; B. Jamieson; H. I. Jang; M. Jiang; K. K. Joo; C. K. Jung; A. Kaboth; T. Kajita; J. Kameda; Y. Karadhzov; T. Katori; E. Kearns; M. Khabibullin; A. Khotjantsev; J. Y. Kim; S. B. Kim; Y. Kishimoto; T. Kobayashi; M. Koga; A. Konaka; L. L. Kormos; A. Korzenev; Y. Koshio; W. R. Kropp; Y. Kudenko; T. Kutter; M. Kuze; L. Labarga; J. Lagoda; M. Laveder; M. Lawe; J. G. Learned; I. T. Lim; T. Lindner; A. Longhin; L. Ludovici; W. Ma; L. Magaletti; K. Mahn; M. Malek; C. Mariani; L. Marti; J. F. Martin; C. Martin; P. P. J. Martins; E. Mazzucato; N. McCauley; K. S. McFarland; C. McGrew; M. Mezzetto; H. Minakata; A. Minamino; S. Mine; O. Mineev; M. Miura; J. Monroe; T. Mori; S. Moriyama; T. Mueller; F. Muheim; M. Nakahata; K. Nakamura; T. Nakaya; S. Nakayama; M. Needham; T. Nicholls; M. Nirkko; Y. Nishimura; E. Noah; J. Nowak; H. Nunokawa; H. M. O'Keeffe; Y. Okajima; K. Okumura; S. M. Oser; E. O'Sullivan; R. A. Owen; Y. Oyama; J. Perez; M. Y. Pac; V. Palladino; J. L. Palomino; V. Paolone; D. Payne; O. Perevozchikov; J. D. Perkin; C. Pistillo; S. Playfer; M. Posiadala-Zezula; J. -M. Poutissou; B. Quilain; M. Quinto; E. Radicioni; P. N. Ratoff; M. Ravonel; M. Rayner; A. Redij; F. Retiere; C. Riccio; E. Richard; E. Rondio; H. J. Rose; M. Ross-Lonergan; C. Rott; S. D. Rountree; A. Rubbia; R. Sacco; M. Sakuda; M. C. Sanchez; E. Scantamburlo; K. Scholberg; M. Scott; Y. Seiya; T. Sekiguchi; H. Sekiya; A. Shaikhiev; I. Shimizu; M. Shiozawa; S. Short; G. Sinnis; M. B. Smy; J. Sobczyk; H. W. Sobel; T. Stewart; J. L. Stone; Y. Suda; Y. Suzuki; A. T. Suzuki; R. Svoboda; R. Tacik; A. Takeda; A. Taketa; Y. Takeuchi; H. A. Tanaka; H. K. M. Tanaka; H. Tanaka; R. Terri; L. F. Thompson; M. Thorpe; S. Tobayama; N. Tolich; T. Tomura; C. Touramanis; T. Tsukamoto; M. Tzanov; Y. Uchida; M. R. Vagins; G. Vasseur; R. B. Vogelaar; C. W. Walter; D. Wark; M. O. Wascko; A. Weber; R. Wendell; R. J. Wilkes; M. J. Wilking; J. R. Wilson; T. Xin; K. Yamamoto; C. Yanagisawa; T. Yano; S. Yen; N. Yershov; M. Yokoyama; M. Zito

    2015-01-18T23:59:59.000Z

    Hyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of $CP$ asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hep-ex

  11. ANRV391-NS59-19 ARI 19 June 2009 15:20 The Sudbury Neutrino

    E-Print Network [OSTI]

    Abolmaesumi, Purang

    oscillation, heavy water, Cherenkov detector Abstract The solar neutrino problem arose when the first conversion was taking place--a hallmark of neutrino oscillation and mass. The solar models were vindicatedANRV391-NS59-19 ARI 19 June 2009 15:20 R E V I E W S IN A D V A N CE The Sudbury Neutrino

  12. Neutrino-Argon Interaction with GENIE Event Generator

    SciTech Connect (OSTI)

    Chesneanu, Daniela [Faculty of Physics, University of Bucharest, Bucharest (Romania); National Institute for Nuclear Physics and Engineering 'Horia Hulubei' Bucharest-Magurele (Romania)

    2010-11-24T23:59:59.000Z

    Neutrinos are very special particles, have only weak interactions, except gravity, and are produced in very different processes in Nuclear and Particle Physics. Neutrinos are, also, messengers from astrophysical objects, as well as relics from Early Universe. Therefore, its can give us information on processes happening in the Universe, during its evolution, which cannot be studied otherwise. The underground instrumentation including a variety of large and very large detectors, thanks to technical breakthroughs, have achieved new fundamental results like the solution of the solar neutrino puzzle and the evidence for Physics beyond the Standard Model of elementary interactions in the neutrino sector with non-vanishing neutrino masses and lepton flavour violation.Two of the LAGUNA(Large Apparatus studying Grand Unification and Neutrino Astrophysics) detectors, namely: GLACIER (Giant Liquid Argon Charge Imaging ExpeRiment) and LENA (Low Energy Neutrino Astrophysics) could be emplaced in 'Unirea' salt mine from Slanic-Prahova, Romania. A detailed analysis of the conditions and advantages is necessary. A few results have been presented previously. In the present work, we propose to generate events and compute the cross sections for interactions between neutrino and Argon-40, to estimate possible detection performances and event types. For doing this, we use the code GENIE(G lowbar enerates E lowbar vents for N lowbar eutrino I lowbar nteraction E lowbar xperiments). GENIE Code is an Object-Oriented Neutrino MC Generator supported and developed by an international collaboration of neutrino interaction experts.

  13. Lepton Mixing Predictions from (Generalised) CP and Discrete Flavour Symmetry

    E-Print Network [OSTI]

    Thomas Neder

    2015-03-31T23:59:59.000Z

    An important class of flavour groups, that are subgroups of $U(3)$ and that predict experimentally viable lepton mixing parameters including Majorana phases, is the $\\Delta(6n^2)$ series. The most well-known member is $\\Delta(24)=S_4$. I present results of several extensive studies of lepton mixing predictions obtained in models with a $\\Delta(6n^2)$ flavour group that preserve either the full residual $Z_2\\times Z_2$ or a $Z_2$ subgroup for neutrinos and can include a generalised CP symmetry. Predictions include mixing angles and Dirac CP phase generally; and if invariance under a generalised CP symmetry is included, also Majorana phases. For this, the interplay of flavour group and generalised CP symmetry has to be studied carefully.

  14. A complete survey of texture zeros in the lepton mass matrices

    E-Print Network [OSTI]

    Patrick Otto Ludl; Walter Grimus

    2014-10-16T23:59:59.000Z

    We perform a systematic and complete analysis of texture zeros in the lepton mass matrices and identify all viable and maximally restrictive cases of pairs (M_\\ell, M_D) and (M_\\ell, M_L), where M_\\ell, M_D and M_L are the charged-lepton, Dirac neutrino and Majorana neutrino mass matrices, respectively. To this end, we perform a thorough analysis of textures which are equivalent through weak-basis permutations. Furthermore, we introduce numerical measures for the predictivity of textures and apply them to the viable and maximally restrictive texture zero models. It turns out that for Dirac neutrinos these models can at most predict the smallest neutrino mass and the CKM-type phase of the mixing matrix. For Majorana neutrinos most models can, in addition, predict the effective neutrino mass for neutrinoless double beta decay. Apart from one model, which has marginal predictive power with respect to sin^2(theta_23), no other model can predict any of the already measured observables.

  15. On the 17-keV neutrino

    SciTech Connect (OSTI)

    Hime, A.

    1993-04-01T23:59:59.000Z

    A brief review on the status of the 17-keV neutrino is presented. Several different experiments found spectral distortions which were consistently interpreted as evidence for a heavy neutrino admixture in [beta] decay. Recent experiments, however, rule out the existence of a 17-keV neutrino as well as escaping criticisms of earlier null results. Moreover, the majority of positive results have been reinterpreted in terms of instrumental effects, despite the need for a different explanation in each case. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation.

  16. On the 17-keV neutrino

    SciTech Connect (OSTI)

    Hime, A.

    1993-04-01T23:59:59.000Z

    A brief review on the status of the 17-keV neutrino is presented. Several different experiments found spectral distortions which were consistently interpreted as evidence for a heavy neutrino admixture in {beta} decay. Recent experiments, however, rule out the existence of a 17-keV neutrino as well as escaping criticisms of earlier null results. Moreover, the majority of positive results have been reinterpreted in terms of instrumental effects, despite the need for a different explanation in each case. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation.

  17. ``STUDIES OF THE SUDBURY NEUTRINO OBSERVATORY DETECTOR AND SONOLUMINESCENCE USING A SONOLUMINESCENT SOURCE''

    E-Print Network [OSTI]

    contraptions used in the experiments. Godwin Mayers helped out with many electronics tasks. Jim Cook, Chuck heavy water Cerenkov solar neutrino detector. 1000 metric tonnes of heavy water is used as a neutrino target and detection medium. SNO is designed to measure the flux and energy spectrum of high energy solar

  18. Possible deviation from the tri-bimaximal neutrino mixing in a seesaw model

    SciTech Connect (OSTI)

    Kang, Sin Kyu; Xing Zhizhong; Zhou Shun [School of Physics, Seoul National University, Seoul 151-734 (Korea, Republic of); CCAST (World Laboratory), P.O. Box 8730, Beijing 100080 (China) and Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, Beijing 100049 (China)

    2006-01-01T23:59:59.000Z

    We propose a simple but suggestive seesaw model with two phenomenological conjectures: three heavy (right-handed) Majorana neutrinos are degenerate in mass in the symmetry limit and three light Majorana neutrinos have the tri-bimaximal mixing pattern V{sub 0}. We show that a small mass splitting between the first generation and the other two generations of heavy Majorana neutrinos is responsible for the deviation of the solar neutrino mixing angle {theta}{sub 12} from its initial value 35.3 deg. given by V{sub 0}, and the slight breaking of the mass degeneracy between the second and third generations of heavy Majorana neutrinos results in a small mixing angle {theta}{sub 13} and a tiny departure of the atmospheric neutrino mixing angle {theta}{sub 23} from 45 deg. It turns out that a normal hierarchy of the light neutrino mass spectrum is favored in this seesaw scenario.

  19. Discriminating Majorana Neutrino Textures in the light of Baryon Asymmetry

    E-Print Network [OSTI]

    Manikanta Borah; Debasish Borah; Mrinal Kumar Das

    2015-04-13T23:59:59.000Z

    We study all possible texture zeros in the Majorana neutrino mass matrix which are allowed from neutrino oscillation as well as cosmology data when the charged lepton mass matrix is assumed to take the diagonal form. In case of one-zero texture, we write down the Majorana phases which are assumed to be equal and the lightest neutrino mass as a function of the Dirac CP phase. In case of two-zero texture, we numerically evaluate all the three CP phases and lightest neutrino mass by solving four real constraint equations. We then constrain texture zero mass matrices from the requirement of producing correct baryon asymmetry through the mechanism of leptogenesis. Adopting a type I seesaw framework, we consider the CP violating out of equilibrium decay of the lightest right handed neutrino as the source of lepton asymmetry. Apart from discriminating between the texture zero mass matrices and light neutrino mass hierarchy, we also constrain the Dirac and Majorana CP phases so that the observed baryon asymmetry can be produced. In two-zero texture, we further constrain the diagonal form of Dirac neutrino mass matrix from the requirement of producing correct baryon asymmetry.

  20. Naturalness and the neutrino matrix

    SciTech Connect (OSTI)

    Sayre, J. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Wiesenfeldt, S. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Institut fur Theoretische Teilchenphysik, Universitaet Karlsruhe, 76128 Karlsruhe (Germany)

    2008-03-01T23:59:59.000Z

    The observed pattern of neutrino mass splittings and mixing angles indicates that their family structure is significantly different from that of the charged fermions. We investigate the implications of these data for the fermion mass matrices in grand-unified theories with a type-I seesaw mechanism. We show that, with simple assumptions, naturalness leads to a strongly hierarchical Majorana mass matrix for heavy right-handed neutrinos and a partially cascade form for the Dirac neutrino matrix. We consider various model building scenarios which could alter this conclusion, and discuss their consequences for the construction of a natural model. We find that including partially lopsided matrices can aid us in generating a satisfying model.

  1. Recent Results in Neutrino Physics

    E-Print Network [OSTI]

    K. V. L. Sarma

    1994-11-07T23:59:59.000Z

    This is a survey of the current experimental information on some of the interesting issues in neutrino physics: neutrino species, neutrino masses, neutrino magnetic moments, solar neutrinos, and the atmospheric neutrino anomaly.

  2. Flavor Physics Data from the Heavy Flavor Averaging Group (HFAG)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Heavy Flavor Averaging Group (HFAG) was established at the May 2002 Flavor Physics and CP Violation Conference in Philadelphia, and continues the LEP Heavy Flavor Steering Group's tradition of providing regular updates to the world averages of heavy flavor quantities. Data are provided by six subgroups that each focus on a different set of heavy flavor measurements: B lifetimes and oscillation parameters, Semi-leptonic B decays, Rare B decays, Unitarity triangle parameters, B decays to charm final states, and Charm Physics.

  3. Neutrino Physics, Superbeams, and the Neutrino Factory

    E-Print Network [OSTI]

    Boris Kayser

    2003-06-09T23:59:59.000Z

    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.

  4. Cosmic neutrino cascades from secret neutrino interactions

    E-Print Network [OSTI]

    Kenny C. Y. Ng; John F. Beacom

    2014-11-01T23:59:59.000Z

    The first detection of high-energy astrophysical neutrinos by IceCube provides new opportunities for tests of neutrino properties. The long baseline through the Cosmic Neutrino Background (C$\

  5. Neutrino Theory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    operators in the Lagrangian (Majorana mass terms), or both. The ongoing neutrinoless double-beta decay searches may be able to shine light on the matter. But the neutrino sector...

  6. Classification of lepton mixing matrices from finite residual symmetries

    E-Print Network [OSTI]

    Renato M. Fonseca; Walter Grimus

    2014-08-19T23:59:59.000Z

    Assuming that neutrinos are Majorana particles, we perform a complete classification of all possible mixing matrices which are fully determined by residual symmetries in the charged-lepton and neutrino mass matrices. The classification is based on the assumption that the residual symmetries originate from a finite flavour symmetry group. The mathematical tools which allow us to accomplish this classification are theorems on sums of roots of unity. We find 17 sporadic cases plus one infinite series of mixing matrices associated with three-flavour mixing, all of which have already been discussed in the literature. Only the infinite series contains mixing matrices which are compatible with the data at the 3 sigma level.

  7. Evidence for the Appearance of Atmospheric Tau Neutrinos in Super-Kamiokande

    E-Print Network [OSTI]

    Super-Kamiokande Collaboration

    2013-06-26T23:59:59.000Z

    Super-Kamiokande atmospheric neutrino data were fit with an unbinned maximum likelihood method to search for the appearance of tau leptons resulting from the interactions of oscillation-generated tau neutrinos in the detector. Relative to the expectation of unity, the tau normalization is found to be $1.42 \\pm 0.35 \\ (stat) {\\}^{+0.14}_{-0.12}\\ (syst) $ excluding the no-tau-appearance hypothesis, for which the normalization would be zero, at the 3.8$\\sigma$ level. We estimate that $180.1 \\pm 44.3\\ (stat) {\\}^{+17.8}_{-15.2}\\ (syst)$ tau leptons were produced in the 22.5 kton fiducial volume of the detector by tau neutrinos during the 2806 day running period. In future analyses, this large sample of selected tau events will allow the study of charged current tau neutrino interaction physics with oscillation produced tau neutrinos.

  8. Four-Way Neutrino Oscillations

    E-Print Network [OSTI]

    V. Barger; T. J. Weiler; K. Whisnant

    1997-12-22T23:59:59.000Z

    We present a four-neutrino model with three active neutrinos and one sterile neutrino which naturally has maximal $\

  9. Lepton masses, mixings, and flavor-changing neutral currents in a minimal S{sub 3}-invariant extension of the standard model

    SciTech Connect (OSTI)

    Mondragon, A.; Mondragon, M.; Peinado, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 Mexico D.F. (Mexico)

    2007-10-01T23:59:59.000Z

    The mass matrices of the charged leptons and neutrinos, previously derived in a minimal S{sub 3}-invariant extension of the standard model, were reparametrized in terms of their eigenvalues. We obtained explicit, analytical expressions for all entries in the neutrino mixing matrix, V{sub PMNS}, the neutrino mixing angles, and the Majorana phases as functions of the masses of charged leptons and neutrinos in excellent agreement with the latest experimental values. The resulting V{sub PMNS} matrix is very close to the tribimaximal form of the neutrino mixing matrix. We also derived explicit, analytical expressions for the matrices of the Yukawa couplings and computed the branching ratios of some selected flavor-changing neutral current processes as functions of the masses of the charged leptons and the neutral Higgs bosons. We find that the S{sub 3}xZ{sub 2} flavor symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector well below the present experimental upper bounds by many orders of magnitude.

  10. Double Beta Decay, Lepton Flavour Violation and Collider Signatures of Left-Right Symmetric Models with Spontaneous D Parity Breaking

    E-Print Network [OSTI]

    Frank F. Deppisch; Tomas E. Gonzalo; Sudhanwa Patra; Narendra Sahu; Utpal Sarkar

    2014-10-23T23:59:59.000Z

    We propose a class of left-right symmetric models (LRSMs) with spontaneous D parity breaking, where SU(2)_R breaks at the TeV scale while discrete left-right symmetry breaks around 10^9 GeV. By embedding this framework in a non-supersymmetric SO(10) Grand Unified Theory (GUT) with Pati-Salam symmetry as the highest intermediate breaking step, we obtain g_R / g_L ~ 0.6 between the right- and left-handed gauge couplings at the TeV scale. This leads to a suppression of beyond the Standard Model phenomena induced by the right-handed gauge coupling. Here we focus specifically on the consequences for neutrinoless double beta decay, low energy lepton flavour violation and LHC signatures due to the suppressed right handed currents. Interestingly, the reduced g_R allows us to interpret an excess of events observed recently in the range of 1.9 TeV to 2.4 TeV by the CMS group at the LHC as the signature of a right handed gauge boson in LRSMs with spontaneous D parity breaking. Moreover, the reduced right-handed gauge coupling also strongly suppresses the non-standard contribution of heavy states to the neutrinoless double beta decay rate as well as the amplitude of low energy lepton flavour violating processes. In a dominant type-II Seesaw mechanism of neutrino mass generation, we find that both sets of observables provide stringent and complimentary bounds which make it challenging to observe the scenario at the LHC.

  11. Vertical Structure of Neutrino Dominated Accretion Disks and Neutrino Transport in the disks

    E-Print Network [OSTI]

    Zhen Pan; Ye-Fei Yuan

    2012-09-06T23:59:59.000Z

    We investigate the vertical structure of neutrino dominated accretion disks by self-consistently considering the detailed microphysics, such as the neutrino transport, vertical hydrostatic equilibrium, the conservation of lepton number, as well as the balance between neutrino cooling, advection cooling and viscosity heating. After obtaining the emitting spectra of neutrinos and antineutrinos by solving the one dimensional Boltzmann equation of neutrino and antineutrino transport in the disk, we calculate the neutrino/antineutrino luminosity and their annihilation luminosity. We find that the total neutrino and antineutrino luminosity is about $10^{54}$ ergs/s and their annihilation luminosity is about $5\\times10^{51}$ ergs/s with an extreme accretion rate $10 M_{\\rm {sun}}$/s and an alpha viscosity $\\alpha=0.1$. In addition, we find that the annihilation luminosity is sensitive to the accretion rate and will not exceed $10^{50}$ ergs/s which is not sufficient to power the most fireball of GRBs, if the accretion rate is lower than $1 M_{\\rm {sun}}$/s. Therefore, the effects of the spin of black hole or/and the magnetic field in the accretion flow might be introduced to power the central engine of GRBs.

  12. Phenomenology of Neutrino Oscillations

    E-Print Network [OSTI]

    S. M. Bilenky; C. Giunti; W. Grimus

    1999-06-04T23:59:59.000Z

    This review is focused on neutrino mixing and neutrino oscillations in the light of the recent experimental developments. After discussing possible types of neutrino mixing for Dirac and Majorana neutrinos and considering in detail the phenomenology of neutrino oscillations in vacuum and matter, we review all existing evidence and indications in favour of neutrino oscillations that have been obtained in the atmospheric, solar and LSND experiments. We present the results of the analyses of the neutrino oscillation data in the framework of mixing of three and four massive neutrinos and investigate possibilities to test the different neutrino mass and mixing schemes obtained in this way. We also discuss briefly future neutrino oscillation experiments.

  13. Neutrino masses and Neutrinoless Double Beta Decay: Status and expectations

    E-Print Network [OSTI]

    Oliviero Cremonesi

    2010-02-07T23:59:59.000Z

    Two most outstanding questions are puzzling the world of neutrino Physics: the possible Majorana nature of neutrinos and their absolute mass scale. Direct neutrino mass measurements and neutrinoless double beta decay (0nuDBD) are the present strategy to solve the puzzle. Neutrinoless double beta decay violates lepton number by two units and can occurr only if neutrinos are massive Majorana particles. A positive observation would therefore necessarily imply a new regime of physics beyond the standard model, providing fundamental information on the nature of the neutrinos and on their absolute mass scale. After the observation of neutrino oscillations and given the present knowledge of neutrino masses and mixing parameters, a possibility to observe 0nuDBDD at a neutrino mass scale in the range 10-50 meV could actually exist. This is a real challenge faced by a number of new proposed projects. Present status and future perpectives of neutrinoless double-beta decay experimental searches is reviewed. The most important parameters contributing to the experimental sensitivity are outlined. A short discussion on nuclear matrix element calculations is also given. Complementary measurements to assess the absolute neutrino mass scale (cosmology and single beta decays) are also discussed.

  14. Heavy flavor production in the STAR experiment

    E-Print Network [OSTI]

    Barbara Trzeciak; for the STAR Collaboration

    2014-09-11T23:59:59.000Z

    In this paper, recent STAR heavy flavor measurements in proton-proton and heavy-ion collisions are highlighted. We report studies of open charm mesons, reconstructed directly from hadronic decay products, and studies of electrons from semi-leptonic decays of heavy flavor hadrons. We also present J/$\\psi$ measurements via the di-electron decay channel at various collision systems and energies. In Au+Au collisions the energy dependence of J/$\\psi$ production measured at $\\sqrt{s_{NN}}$ = 39, 62.4 and 200 GeV is shown. Finally, prospects of heavy flavor measurements with the STAR detector upgrades are discussed.

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

    SciTech Connect (OSTI)

    Babi?, Andrej [Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 842 48 Bratislava (Slovakia); Šimkovic, Fedor [Bogoliubov Laboratory of Theoretical Physics, JINR, Joliot-Curie 6, 141980 Dubna, Moscow region, Russia and Institute of Experimental and Applied Physics, Czech Technical University, CZ-128 00 Prague (Czech Republic)

    2013-12-30T23:59:59.000Z

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

  16. Solar Neutrinos and the Decaying Neutrino Hypothesis

    E-Print Network [OSTI]

    Jeffrey M. Berryman; Andre de Gouvea; Daniel Hernandez

    2014-11-02T23:59:59.000Z

    We explore, mostly using data from solar neutrino experiments, the hypothesis that the neutrino mass eigenstates are unstable. We find that, by combining $^8$B solar neutrino data with those on $^7$Be and lower-energy solar neutrinos, one obtains a mostly model-independent bound on both the $\

  17. Can the four-zero-texture mass matrix model reproduce the observed quark and lepton mixing angles and CP-violating phases?

    SciTech Connect (OSTI)

    Matsuda, Koichi; Nishiura, Hiroyuki [Center for High Energy Physics, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Faculty of Information Science and Technology, Osaka Institute of Technology, Hirakata, Osaka 573-0196 (Japan)

    2006-08-01T23:59:59.000Z

    We reconsider a universal mass matrix model which has a seesaw-invariant structure with four-zero texture common to all quarks and leptons. The Cabibbo-Kobayashi-Maskawa (CKM) quark and Maki-Nakagawa-Sakata (MNS) lepton mixing matrices of the model are analyzed analytically. We show that the model can be consistent with all the experimental data of neutrino oscillation and quark mixings by tuning free parameters of the model. It is also shown that the model predicts a relatively large value for the (1, 3) element of the MNS lepton mixing matrix (U{sub MNS}){sub 13}{sup 2}{approx_equal}(0.041-9.6)x10{sup -2}. Using the seesaw mechanism, we also discuss the conditions for the components of the Dirac and the right-handed Majorana neutrino mass matrices which lead to the neutrino mass matrix consistent with the experimental data.

  18. Solar Neutrinos

    E-Print Network [OSTI]

    R. G. H. Robertson

    2006-02-05T23:59:59.000Z

    Experimental work with solar neutrinos has illuminated the properties of neutrinos and tested models of how the sun produces its energy. Three experiments continue to take data, and at least seven are in various stages of planning or construction. In this review, the current experimental status is summarized, and future directions explored with a focus on the effects of a non-zero theta-13 and the interesting possibility of directly testing the luminosity constraint. Such a confrontation at the few-percent level would provide a prediction of the solar irradiance tens of thousands of years in the future for comparison with the present-day irradiance. A model-independent analysis of existing low-energy data shows good agreement between the neutrino and electromagnetic luminosities at the +/- 20 % level.

  19. Neutrino Physics: Fundamentals of Neutrino Oscillations

    E-Print Network [OSTI]

    C. W. Kim

    1996-07-22T23:59:59.000Z

    In this lecture we review some of the basic properties of neutrinos, in particular their mass and the oscillation behavior. First we discuss how to describe the neutrino mass. Then, under the assumption that neutrinos are massive and mixed, the fundamentals of the neutrino oscillations are discussed with emphasis on subtle aspects which have been overlooked in the past. We then review the terrestrial neutrino oscillation experiments in the framework of three generations of neutrinos with the standard mass hierarchy. Finally, a brief summary of the current status of the solar and atmospheric neutrino problems will be given.

  20. Large neutrino asymmetries from neutrino oscillations

    E-Print Network [OSTI]

    R. Foot; M. J. Thomson; R. R. Volkas

    1995-09-19T23:59:59.000Z

    We re-examine neutrino oscillations in the early universe. Contrary to previous studies, we show that large neutrino asymmetries can arise due to oscillations between ordinary neutrinos and sterile neutrinos. This means that the Big Bang Nucleosynthesis (BBN) bounds on the mass and mixing of ordinary neutrinos with sterile neutrinos can be evaded. Also, it is possible that the neutrino asymmetries can be large (i.e. $\\stackrel{>}{\\sim} 10\\%$), and hence have a significant effect on BBN through nuclear reaction rates.

  1. Dynamics of disentanglement, density matrix, and coherence in neutrino oscillations

    SciTech Connect (OSTI)

    Wu Jun; Boyanovsky, Daniel [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Hutasoit, Jimmy A.; Holman, Richard [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2010-07-01T23:59:59.000Z

    In charged current weak interaction processes, neutrinos are produced in an entangled state with the charged lepton. This correlated state is disentangled by the measurement of the charged lepton in a detector at the production site. We study the dynamical aspects of disentanglement, propagation, and detection, in particular, the conditions under which the disentangled state is a coherent superposition of mass eigenstates. The appearance and disappearance far-detection processes are described from the time evolution of this disentangled 'collapsed' state. The familiar quantum mechanical interpretation and factorization of the detection rate emerges when the quantum state is disentangled on time scales much shorter than the inverse oscillation frequency, in which case the final detection rate factorizes in terms of the usual quantum mechanical transition probability provided the final density of states is insensitive to the neutrino energy difference. We suggest possible corrections for short-baseline experiments. If the charged lepton is unobserved, neutrino oscillations and coherence are described in terms of a reduced density matrix obtained by tracing out an unobserved charged lepton. The diagonal elements in the mass basis describe the production of mass eigenstates whereas the off-diagonal ones provide a measure of coherence. It is shown that coherences are of the same order of the diagonal terms on time scales up to the inverse oscillation frequency, beyond which the coherences oscillate as a result of the interference between mass eigenstates.

  2. Secret of Neutrino Oscillations

    E-Print Network [OSTI]

    Dmitry Zhuridov

    2012-03-08T23:59:59.000Z

    The new effect of partial and full destruction of the neutrino oscillation pattern due to the neutrino wave packets separation in the transverse plane to the direction of the neutrino propagation is investigated. It is shown that this effect is significant in the real oscillation data, in particular, for the solar neutrinos, and dramatically changes the extracted physical properties of neutrinos.

  3. Fast Neutrino Decay in the Minimal Seesaw Model

    E-Print Network [OSTI]

    Anjans S. Joshipura; Saurabh D. Rindani

    1992-05-13T23:59:59.000Z

    Neutrino decay in the minimal seesaw model containing three right handed neutrinos and a complex $SU(2)\\times U(1)$ singlet Higgs in addition to the standard model fields is considered. A global horizontal symmetry $U(1)_H$ is imposed, which on spontaneous breaking gives rise to a Goldstone boson. This symmetry is chosen in a way that makes a) the contribution of heavy ($\\leq$ MeV) majorana neutrinos to the neutrinoless double beta decay amplitude vanish and b) allows the heavy neutrino to decay to a lighter neutrino and the Goldstone boson. It is shown that this decay can occur at a rate much faster than in the original Majoron model even if one does not introduce any additional Higgs fields as is done in the literature. Possibility of describing the 17 keV neutrino in this minimal seesaw model is investigated. While most of the cosmological and astrophysical constraints on the 17 keV neutrino can be satisfied in this model, the laboratory limits coming from the neutrino oscillations cannot be easily met. An extension which removes this inadequacy and offers a consistent description of the 17 keV neutrino is discussed.

  4. An infrared origin of leptonic mixing and its test at DeepCore

    E-Print Network [OSTI]

    F. Terranova

    2011-10-10T23:59:59.000Z

    Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.

  5. Sterile neutrinos: direct mixing effects versus induced mass matrix of active neutrinos

    E-Print Network [OSTI]

    Alexei Yu. Smirnov; Renata Zukanovich Funchal

    2006-06-14T23:59:59.000Z

    Mixing of active neutrinos with sterile ones generate ``induced'' contributions to the mass matrix of active neutrinos $\\sim m_S \\sin^2\\theta_{aS}$, where $m_S$ is the Majorana mass of the sterile neutrino and $\\theta_{aS}$ is the active-sterile mixing angle. We study possible effects of the induced matrix which can modify substantially the implications of neutrino oscillation results. We have identified the regions of $m_S$ and $\\sin^2\\theta_{aS}$ where the induced matrix (i) provides the dominant structures, (ii) gives the sub-dominant effects and (iii) where its effects can be neglected. The induced matrix can be responsible for peculiar properties of the lepton mixing and neutrino mass spectrum, in particular, it can generate the tri-bimaximal mixing. We update and discuss bounds on the induced masses from laboratory measurements, astrophysics and cosmology. We find that substantial impact of the induced matrix is possible if $m_S \\sim 0.1-1$ eV and $\\sin^2\\theta_{aS} \\sim 10^{-3} - 10^{-2}$ or $m_S \\geq 200$ MeV and $\\sin^2\\theta_{aS} \\leq 10^{-9}$. The bounds can be relaxed in cosmological scenarios with low reheating temperature, if sterile neutrinos decay sufficiently fast, or their masses change with time.

  6. S3 x Z2 model for neutrino mass matrices

    E-Print Network [OSTI]

    W. Grimus; L. Lavoura

    2005-08-02T23:59:59.000Z

    We propose a model for lepton mass matrices based on the seesaw mechanism, a complex scalar gauge singlet and a horizontal symmetry $S_3 \\times \\mathbbm{Z}_2$. In a suitable weak basis, the charged-lepton mass matrix and the neutrino Dirac mass matrix are diagonal, but the vacuum expectation value of the scalar gauge singlet renders the Majorana mass matrix of the right-handed neutrinos non-diagonal, thereby generating lepton mixing. When the symmetry $S_3$ is not broken in the scalar potential, the effective light-neutrino Majorana mass matrix enjoys $\\mu$--$\\tau$ interchange symmetry, thus predicting maximal atmospheric neutrino mixing together with $U_{e3} = 0$. A partial and less predictive form of $\\mu$--$\\tau$ interchange symmetry is obtained when the symmetry $S_3$ is softly broken in the scalar potential. Enlarging the symmetry group $S_3 \\times \\mathbbm{Z}_2$ by an additional discrete electron-number symmetry $\\mathbbm{Z}_2^{(e)}$, a more predicitive model is obtained, which is in practice indistinguishable from a previous one based on the group $D_4$.

  7. Neutrino masses and solar neutrinos

    SciTech Connect (OSTI)

    Wolfenstein, L.

    1992-11-01T23:59:59.000Z

    It has been pointed out by Bahcall and Bethe and others that all solar neutrino data can be explained by MSW oscillations with m({nu}{sub {mu}}) {approximately} 10{sup {minus}3} eV consistent with ideas grand unified theories (GUTS). There is a second possibility consistent with GUTS ideas with m({nu}{sub {tau}}) {approximately} 10{sup {minus}2} eV and m({nu} {sub {mu}}) {approximately} 10 {sup {minus}4} eV. The two cases can be distinguished by a measurement of the solar neutrinos from {sup {tau}}Be.

  8. TeV Scale Lepton Number Violation and Baryogenesis

    E-Print Network [OSTI]

    Dev, P S Bhupal; Mohapatra, R N

    2015-01-01T23:59:59.000Z

    Contrary to the common lore based on naive dimensional analysis, the seesaw scale for neutrino masses can be naturally in the TeV range, with small parameters coming from radiative corrections. We present one such class of type-I seesaw models, based on the left-right gauge group $SU(2)_L\\times SU(2)_R\\times U(1)_{B-L}$ realized at the TeV scale, which fits the observed neutrino oscillation parameters as well as other low energy constraints. We discuss how the small parameters of this scenario can arise naturally from one loop effects. The neutrino fits in this model use quasi-degenerate heavy Majorana neutrinos, as also required to explain the matter-antimatter asymmetry in our Universe via resonant leptogenesis mechanism. We discuss the constraints implied by the dynamics of this mechanism on the mass of the right-handed gauge boson in this class of models with enhanced neutrino Yukawa couplings compared to the canonical seesaw model and find a lower bound of $m_{W_R}\\geq 9.9$ TeV for successful leptogenesi...

  9. Structure of Cosmological CP Violation via Neutrino Seesaw

    E-Print Network [OSTI]

    V. Barger; Duane A. Dicus; Hong-Jian He; Tianjun Li

    2003-12-16T23:59:59.000Z

    The cosmological matter-antimatter asymmetry can originate from CP-violating interactions of seesaw Majorana neutrinos via leptogenesis in the thermal phase of the early universe. Having the cosmological CP-phase for leptogenesis requires at least two right-handed Majorana neutrinos. Using only the low energy neutrino observables we quantitatively reconstruct a minimal neutrino seesaw. We establish a general criterion for minimal seesaw schemes in which the cosmological CP-phase is {\\it completely} reconstructed from the low energy CP-phases measured by neutrino oscillation and neutrinoless double-beta decay experiments. We reveal and analyze two distinct classes of such minimal schemes that are shown to be highly predictive. Extension of our reconstruction formalism to a three-heavy-neutrino seesaw is discussed.

  10. Neutrino masses and mixing: a flavour symmetry roadmap

    E-Print Network [OSTI]

    S. Morisi; J. W. F. Valle

    2012-06-28T23:59:59.000Z

    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.

  11. Neutrino masses and mixing: a flavour symmetry roadmap

    E-Print Network [OSTI]

    Morisi, S

    2012-01-01T23:59:59.000Z

    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.

  12. Renormalization of a two-loop neutrino mass model

    SciTech Connect (OSTI)

    Babu, K. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States); Julio, J. [Fisika LIPI, Kompleks Puspiptek Serpong, Tangerang 15310, Indonesia and Jožef Stefan Institute, Jamova Cesta 39, 1001 Ljubljana (Slovenia)

    2014-01-01T23:59:59.000Z

    We analyze the renormalization group structure of a radiative neutrino mass model consisting of a singly charged and a doubly charged scalar fields. Small Majorana neutrino masses are generated by the exchange of these scalars via two-loop diagrams. We derive boundedness conditions for the Higgs potential and show how they can be satisfied to energies up to the Planck scale. Combining boundedness and perturbativity constraints with neutrino oscillation phenomenology, new limits on the masses and couplings of the charged scalars are derived. These in turn lead to lower limits on the branching ratios for certain lepton flavor violating (LFV) processes such as ??e?, ??3e and ? – e conversion in nuclei. Improved LFV measurements could test the model, especially in the case of inverted neutrino mass hierarchy where these are more prominent.

  13. Beams for European Neutrino Experiments (BENE) Midterm scientific report

    E-Print Network [OSTI]

    Baldini, A; Blondel, A; Campagne, J E; Cavata, C; Donini, A; Dracos, M; Dumarchez, J; Edgecock, R; Efthymiopoulos, I; Garoby, R; Huber, P; Long, K; Lindroos, M; Méot, F; Mezzetto, Mauro; Palladino, V; Rees, G; Sievers, P; Strolin, P; Volpe, C

    2006-01-01T23:59:59.000Z

    The activities of BENE during 2004 and 2005 are reviewed. Neutrino oscillation experiments at accelerators offer the richest possibilities of precision studies of neutrino mixing and mass differences, with the potential of important discoveries including leptonic CP or T violation. Two main options for a major initiative have been studied: 1) a high-energy Neutrino Factory coupled to a large dense magnetized detector; 2) a lower energy betabeam and conventional superbeam, coupled to a very large low-density, non-magnetic, detector. Both offer signi cant scienti c breakthroughs over other planned facilities. Much remains to be done to optimize and establish the cost, performance, and feasibility of either solution so as to allow comparison and decision. The proposal of a FP7 Design Study of a Neutrino Facility to be completed by the end of the decade is being prepared. Its success will require strong support and engagement at CERN and other European laboratories and funding agencies. International contributors...

  14. Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

    SciTech Connect (OSTI)

    Hawthorne, J.F. (ed.)

    1991-01-01T23:59:59.000Z

    This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K{sup 0} decays at CERN; recent K{sup 0} decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results from CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN {rho}{bar {rho}} collider; B physics at CDF; and review of particle astrophysics.

  15. Neutrinos: Theory and Phenomenology

    SciTech Connect (OSTI)

    Parke, Stephen

    2013-10-22T23:59:59.000Z

    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.

  16. Neutrino Factory Downstream Systems

    E-Print Network [OSTI]

    Zisman, Michael S.

    2010-01-01T23:59:59.000Z

    Neutrino Factory Downstream Systems Michael S. Zisman*Factory accelerator systems downstream from the target andthe Neutrino Factory systems downstream of the target and

  17. Lepton Flavor Violation in Predictive SUSY-GUT Models

    SciTech Connect (OSTI)

    Albright, Carl H.; /Northern Illinois U. /Fermilab; Chen, Mu-Chun; /UC, Irvine

    2008-02-01T23:59:59.000Z

    There have been many theoretical models constructed which aim to explain the neutrino masses and mixing patterns. While many of the models will be eliminated once more accurate determinations of the mixing parameters, especially sin{sup 2} 2{theta}{sub 13}, are obtained, charged lepton flavor violation (LFV) experiments are able to differentiate even further among the models. In this paper, they investigate various rare LFV processes, such as {ell}{sub i} {yields} {ell}{sub j} + {gamma} and {mu} - e conversion, in five predictive SUSY SO(10) models and their allowed soft SUSY breaking parameter space in the constrained minimal SUSY standard model (CMSSM). Utilizing the WMAP dark matter constraints, they obtain lower bounds on the branching ratios of these rare processes and find that at least three of the five models they consider give rise to predictions for {mu} {yields} e + {gamma} that will be tested by the MEG collaboration at PSI. in addition, the next generation {mu} - e conversion experiment has sensitivity to the predictions of all five models, making it an even more robust way to test these models. While generic studies have emphasized the dependence of the branching ratios of these rare processes on the reactor neutrino angle, {theta}{sub 13}, and the mass of the heaviest right-handed neutrino, M{sub 3}, they find very massive M{sub 3} is more significant than large {theta}{sub 13} in leading to branching ratios near to the present upper limits.

  18. Dark matter and strong electroweak phase transition in a radiative neutrino mass model

    SciTech Connect (OSTI)

    Ahriche, Amine [Department of Physics, University of Jijel, PB 98 Ouled Aissa, DZ-18000 Jijel (Algeria); Nasri, Salah, E-mail: aahriche@ictp.it, E-mail: snasri@uaeu.ac.ae [Physics Department, UAE University, POB 17551, Al Ain (United Arab Emirates)

    2013-07-01T23:59:59.000Z

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

  19. Self-induced flavor instabilities of a dense neutrino stream in a two-dimensional model

    E-Print Network [OSTI]

    Mirizzi, Alessandro; Saviano, Ninetta

    2015-01-01T23:59:59.000Z

    We consider a simplifed model for self-induced flavor conversions of a dense neutrino gas in two dimensions, showing new solutions that spontaneously break the spatial symmetries of the initial conditions. As a result of the symmetry breaking induced by the neutrino-neutrino interactions, the coherent behavior of the neutrino gas becomes unstable. This instability produces large spatial variations in the flavor content of the ensemble. Furthermore, it also leads to the creation of domains of different net lepton number flux. The transition of the neutrino gas from a coherent to incoherent behavior shows an intriguing analogy with a streaming flow changing from laminar to turbulent regime. These finding would be relevant for the self-induced conversions of neutrinos streaming-off a supernova core.

  20. Thermal and non-thermal leptogenesis in different neutrino mass models with tribimaximal mixings

    E-Print Network [OSTI]

    N. Nimai Singh; H. Zeen Devi; Amal Kr Sarma

    2008-07-15T23:59:59.000Z

    In the present work we study both thermal and non-thermal leptogenesis in all neutrino mass models describing the presently available neutrino mass patterns. We consider the Majorana CP violating phases coming from right-handed Majorana mass matrices to estimate the baryon asymmetry of the universe, for different neutrino mass models namely degenerate, inverted hierarchical and normal hierarchical models, with tribimaximal mixings. Considering two possible diagonal forms of Dirac neutrino mass matrix as either charged lepton or up-quark mass matrix, the right-handed Majorana mass matrices are constructed from the light neutrino mass matrix through the inverse seesaw formula. Only the normal hierarchical model leads to the best predictions for baryon asymmetry of the universe, consistent with observations in both thermal and non-thermal leptogenesis scenario. The analysis though phenomenological may serve as an additional information in the discrimination among the presently available neutrino mass models.

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

    SciTech Connect (OSTI)

    Bellini, F. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma I-00185 (Italy) and INFN - Sezione di Roma, Roma I-00185 (Italy)

    2012-11-20T23:59:59.000Z

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

  2. Perspectives for future neutrino oscillation experiments with accelerators: beams, detectors and physics

    E-Print Network [OSTI]

    Pasquale Migliozzi

    2003-11-21T23:59:59.000Z

    In recent years great progress toward the understanding of the mixing in the leptonic sector has been made. Nonetheless, this field of research is just at the beginning. Further advance by accelerator based neutrino oscillation experiments requires new beams and detectors to reach the wanted physics goals. In this paper we review the next possible steps that can be done for neutrino oscillation experiments with accelerators

  3. 13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS

    E-Print Network [OSTI]

    13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS Updated October 2011 by K compelling evidences for oscillations of neutrinos caused by nonzero neutrino masses and neutrino mixing. The data imply the existence of 3-neutrino mixing in vacuum. We review the theory of neutrino oscillations

  4. 13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS

    E-Print Network [OSTI]

    13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS Written May 2010 by K. Nakamura for oscillations of neutrinos caused by nonzero neutrino masses and neutrino mixing. The data imply the existence of 3-neutrino mixing in vacuum. We review the theory of neutrino oscillations, the phenomenology

  5. The Intermediate Neutrino Program

    E-Print Network [OSTI]

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

    2015-04-01T23:59:59.000Z

    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.

  6. The Intermediate Neutrino Program

    E-Print Network [OSTI]

    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

    2015-01-01T23:59:59.000Z

    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...

  7. Search for neutrinoless decays of the ? lepton

    E-Print Network [OSTI]

    Baringer, Philip S.

    1990-02-01T23:59:59.000Z

    We have searched for neutrinoless ? decays into three charged particles. Evidence of such decays would demonstrate nonconservation of lepton flavor and, in some cases, lepton number. We see no signal for any such neutrinoless ? decays and set upper...

  8. Can Neutrinos be Degenerate in Mass?

    E-Print Network [OSTI]

    John Ellis; Smaragda Lola

    1999-04-13T23:59:59.000Z

    We reconsider the possibility that the masses of the three light neutrinos of the Standard Model might be almost degenerate and close to the present upper limits from Tritium beta decay and cosmology. In such a scenario, the cancellations required by the latest upper limit on neutrinoless double-beta decay enforce near-maximal mixing that may be compatible only with the vacuum-oscillation scenario for solar neutrinos. We argue that the mixing angles yielded by degenerate neutrino mass-matrix textures are not in general stable under small perturbations. We evaluate within the MSSM the generation-dependent one-loop renormalization of neutrino mass-matrix textures that yielded degenerate masses and large mixing at the tree level. We find that m_{nu_e} > m_{nu_mu} > m_{nu_tau} after renormalization, excluding MSW effects on solar neutrinos. We verify that bimaximal mixing is not stable, and show that the renormalized masses and mixing angles are not compatible with all the experimental constraints, even for tanbeta as low as unity. These results hold whether the neutrino masses are generated by a see-saw mechanism with heavy neutrinos weighing approx. 10^{13} GeV or by non-renormalizable interactions at a scale approx. 10^5 GeV. We also comment on the corresponding renormalization effects in the minimal Standard Model, in which m_{nu_e} < m_{nu_mu} < m_{nu_tau}. Although a solar MSW effect is now possible, the perturbed neutrino masses and mixings are still not compatible with atmospheric- and solar-neutrino data.

  9. Super-Kamiokande 0.07 eV Neutrinos in Cosmology: Hot Dark Matter and the Highest Energy Cosmic Rays

    E-Print Network [OSTI]

    Graciela B. Gelmini

    2000-05-25T23:59:59.000Z

    Relic neutrinos with mass in the range indicated by Super-Kamiokande results if neutrino masses are hierarchial (about 0.07 eV) are many times deemed too light to be cosmologically relevant. Here we remark that these neutrinos may significantly contribute to the dark matter of the Universe (with a large lepton asymmetry $L$) and that their existence might be revealed by the spectrum of ultra high energy cosmic rays (maybe even in the absence of a large $L$).

  10. Ultra High Energy Neutrino Astronomy

    E-Print Network [OSTI]

    V. Berezinsky

    2005-05-11T23:59:59.000Z

    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.

  11. Physics Potential of a Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

    E-Print Network [OSTI]

    Abe, K; Andreopoulos, C; Anghel, I; Ariga, A; Ariga, T; Asfandiyarov, R; Askins, M; Back, J J; Ballett, P; Barbi, M; Barker, G J; Barr, G; Bay, F; Beltrame, P; Berardi, V; Bergevin, M; Berkman, S; Berry, T; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bolognesi, S; Boyd, S B; Bravar, A; Bronner, C; Cafagna, F S; Carminati, G; Cartwright, S L; Catanesi, M G; Choi, K; Choi, J H; Collazuol, G; Cowan, G; Cremonesi, L; Davies, G; De Rosa, G; Densham, C; Detwiler, J; Dewhurst, D; Di Lodovico, F; Di Luise, S; Drapier, O; Emery, S; Ereditato, A; Fernández, P; Feusels, T; Finch, A; Fitton, M; Friend, M; Fujii, Y; Fukuda, Y; Fukuda, D; Galymov, V; Ganezer, K; Gonin, M; Gumplinger, P; Hadley, D R; Haegel, L; Haesler, A; Haga, Y; Hartfiel, B; Hartz, M; Hayato, Y; Hierholzer, M; Hill, J; Himmel, A; Hirota, S; Horiuchi, S; Huang, K; Ichikawa, A K; Iijima, T; Ikeda, M; Imber, J; Inoue, K; Insler, J; Intonti, R A; Irvine, T; Ishida, T; Ishino, H; Ishitsuka, M; Itow, Y; Izmaylov, A; Jamieson, B; Jang, H I; Jiang, M; Joo, K K; Jung, C K; Kaboth, A; Kajita, T; Kameda, J; Karadhzov, Y; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kim, J Y; Kim, S B; Kishimoto, Y; Kobayashi, T; Koga, M; Konaka, A; Kormos, L L; Korzenev, A; Koshio, Y; Kropp, W R; Kudenko, Y; Kutter, T; Kuze, M; Labarga, L; Lagoda, J; Laveder, M; Lawe, M; Learned, J G; Lim, I T; Lindner, T; Longhin, A; Ludovici, L; Ma, W; Magaletti, L; Mahn, K; Malek, M; Mariani, C; Marti, L; Martin, J F; Martin, C; Martins, P P J; Mazzucato, E; McCauley, N; McFarland, K S; McGrew, C; Mezzetto, M; Minakata, H; Minamino, A; Mine, S; Mineev, O; Miura, M; Monroe, J; Mori, T; Moriyama, S; Mueller, T; Muheim, F; Nakahata, M; Nakamura, K; Nakaya, T; Nakayama, S; Needham, M; Nicholls, T; Nirkko, M; Nishimura, Y; Noah, E; Nowak, J; Nunokawa, H; O'Keeffe, H M; Okajima, Y; Okumura, K; Oser, S M; O'Sullivan, E; Ovsiannikova, T; Owen, R A; Oyama, Y; Pérez, J; Pac, M Y; Palladino, V; Palomino, J L; Paolone, V; Payne, D; Perevozchikov, O; Perkin, J D; Pistillo, C; Playfer, S; Posiadala-Zezula, M; Poutissou, J -M; Quilain, B; Quinto, M; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A; Redij, A; Retiere, F; Riccio, C; Richard, E; Rondio, E; Rose, H J; Ross-Lonergan, M; Rott, C; Rountree, S D; Rubbia, A; Sacco, R; Sakuda, M; Sanchez, M C; Scantamburlo, E; Scholberg, K; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Shaikhiev, A; Shimizu, I; Shiozawa, M; Short, S; Sinnis, G; Smy, M B; Sobczyk, J; Sobel, H W; Stewart, T; Stone, J L; Suda, Y; Suzuki, Y; Suzuki, A T; Svoboda, R; Tacik, R; Takeda, A; Taketa, A; Takeuchi, Y; Tanaka, H A; Tanaka, H K M; Tanaka, H; Terri, R; Thompson, L F; Thorpe, M; Tobayama, S; Tolich, N; Tomura, T; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vagins, M R; Vasseur, G; Vogelaar, R B; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilson, J R; Xin, T; Yamamoto, K; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Zito, M

    2015-01-01T23:59:59.000Z

    Hyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of $CP$ asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW $\\times$ 10$^7$ sec integrated proton beam power (corresponding to $1.56\\times10^{22}$ protons on target with a 30 GeV proton beam) to a $2.5$-degree off-axis neutrino beam, it is expected that the leptonic $CP$ phase $\\delta_{CP}$ can be determined to better than 19 degrees for all possible values of $\\delta_{CP}$, and $CP$ violation can be establis...

  12. Physics Potential of a Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

    E-Print Network [OSTI]

    Hyper-Kamiokande Proto-Collaboraion; :; K. Abe; H. Aihara; C. Andreopoulos; I. Anghel; A. Ariga; T. Ariga; R. Asfandiyarov; M. Askins; J. J. Back; P. Ballett; M. Barbi; G. J. Barker; G. Barr; F. Bay; P. Beltrame; V. Berardi; M. Bergevin; S. Berkman; T. Berry; S. Bhadra; F. d. M. Blaszczyk; A. Blondel; S. Bolognesi; S. B. Boyd; A. Bravar; C. Bronner; F. S. Cafagna; G. Carminati; S. L. Cartwright; M. G. Catanesi; K. Choi; J. H. Choi; G. Collazuol; G. Cowan; L. Cremonesi; G. Davies; G. De Rosa; C. Densham; J. Detwiler; D. Dewhurst; F. Di Lodovico; S. Di Luise; O. Drapier; S. Emery; A. Ereditato; P. Fernández; T. Feusels; A. Finch; M. Fitton; M. Friend; Y. Fujii; Y. Fukuda; D. Fukuda; V. Galymov; K. Ganezer; M. Gonin; P. Gumplinger; D. R. Hadley; L. Haegel; A. Haesler; Y. Haga; B. Hartfiel; M. Hartz; Y. Hayato; M. Hierholzer; J. Hill; A. Himmel; S. Hirota; S. Horiuchi; K. Huang; A. K. Ichikawa; T. Iijima; M. Ikeda; J. Imber; K. Inoue; J. Insler; R. A. Intonti; T. Irvine; T. Ishida; H. Ishino; M. Ishitsuka; Y. Itow; A. Izmaylov; B. Jamieson; H. I. Jang; M. Jiang; K. K. Joo; C. K. Jung; A. Kaboth; T. Kajita; J. Kameda; Y. Karadhzov; T. Katori; E. Kearns; M. Khabibullin; A. Khotjantsev; J. Y. Kim; S. B. Kim; Y. Kishimoto; T. Kobayashi; M. Koga; A. Konaka; L. L. Kormos; A. Korzenev; Y. Koshio; W. R. Kropp; Y. Kudenko; T. Kutter; M. Kuze; L. Labarga; J. Lagoda; M. Laveder; M. Lawe; J. G. Learned; I. T. Lim; T. Lindner; A. Longhin; L. Ludovici; W. Ma; L. Magaletti; K. Mahn; M. Malek; C. Mariani; L. Marti; J. F. Martin; C. Martin; P. P. J. Martins; E. Mazzucato; N. McCauley; K. S. McFarland; C. McGrew; M. Mezzetto; H. Minakata; A. Minamino; S. Mine; O. Mineev; M. Miura; J. Monroe; T. Mori; S. Moriyama; T. Mueller; F. Muheim; M. Nakahata; K. Nakamura; T. Nakaya; S. Nakayama; M. Needham; T. Nicholls; M. Nirkko; Y. Nishimura; E. Noah; J. Nowak; H. Nunokawa; H. M. O'Keeffe; Y. Okajima; K. Okumura; S. M. Oser; E. O'Sullivan; T. Ovsiannikova; R. A. Owen; Y. Oyama; J. Pérez; M. Y. Pac; V. Palladino; J. L. Palomino; V. Paolone; D. Payne; O. Perevozchikov; J. D. Perkin; C. Pistillo; S. Playfer; M. Posiadala-Zezula; J. -M. Poutissou; B. Quilain; M. Quinto; E. Radicioni; P. N. Ratoff; M. Ravonel; M. A. Rayner; A. Redij; F. Retiere; C. Riccio; E. Richard; E. Rondio; H. J. Rose; M. Ross-Lonergan; C. Rott; S. D. Rountree; A. Rubbia; R. Sacco; M. Sakuda; M. C. Sanchez; E. Scantamburlo; K. Scholberg; M. Scott; Y. Seiya; T. Sekiguchi; H. Sekiya; A. Shaikhiev; I. Shimizu; M. Shiozawa; S. Short; G. Sinnis; M. B. Smy; J. Sobczyk; H. W. Sobel; T. Stewart; J. L. Stone; Y. Suda; Y. Suzuki; A. T. Suzuki; R. Svoboda; R. Tacik; A. Takeda; A. Taketa; Y. Takeuchi; H. A. Tanaka; H. K. M. Tanaka; H. Tanaka; R. Terri; L. F. Thompson; M. Thorpe; S. Tobayama; N. Tolich; T. Tomura; C. Touramanis; T. Tsukamoto; M. Tzanov; Y. Uchida; M. R. Vagins; G. Vasseur; R. B. Vogelaar; C. W. Walter; D. Wark; M. O. Wascko; A. Weber; R. Wendell; R. J. Wilkes; M. J. Wilking; J. R. Wilson; T. Xin; K. Yamamoto; C. Yanagisawa; T. Yano; S. Yen; N. Yershov; M. Yokoyama; M. Zito

    2015-03-31T23:59:59.000Z

    Hyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of $CP$ asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW $\\times$ 10$^7$ sec integrated proton beam power (corresponding to $1.56\\times10^{22}$ protons on target with a 30 GeV proton beam) to a $2.5$-degree off-axis neutrino beam, it is expected that the leptonic $CP$ phase $\\delta_{CP}$ can be determined to better than 19 degrees for all possible values of $\\delta_{CP}$, and $CP$ violation can be established with a statistical significance of more than $3\\,\\sigma$ ($5\\,\\sigma$) for $76\\%$ ($58\\%$) of the $\\delta_{CP}$ parameter space. Using both $\

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

    E-Print Network [OSTI]

    Watabe, Masaki

    2010-07-14T23:59:59.000Z

    neutrino is massive and a Majorana particle. Neutrinoless double beta decay is one of the nuclear processes that violates the total lepton number and related to Majorana nature of neutrinos. Details are discussed in Ref. [12, 15, 16, 17, 18, 19, 20, 21... be measured in two distinct ways. First, the experimental search for neutrinoless double beta decays is one of the possible ways to measure the "absolute" mass scale. The SM predicts the double beta decay and the process is experimentally con rmed by Elliot...

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

    E-Print Network [OSTI]

    Watabe, Masaki

    2010-07-14T23:59:59.000Z

    neutrino is massive and a Majorana particle. Neutrinoless double beta decay is one of the nuclear processes that violates the total lepton number and related to Majorana nature of neutrinos. Details are discussed in Ref. [12, 15, 16, 17, 18, 19, 20, 21... be measured in two distinct ways. First, the experimental search for neutrinoless double beta decays is one of the possible ways to measure the "absolute" mass scale. The SM predicts the double beta decay and the process is experimentally con rmed by Elliot...

  15. Neutrino matter potentials induced by Earth

    E-Print Network [OSTI]

    J. Linder

    2006-01-15T23:59:59.000Z

    An instructive method of deriving the matter potentials felt by neutrinos propagating through matter on Earth is presented. This paper thoroughly guides the reader through the calculations involving the effective weak Hamiltonian for lepton and quark scattering. The matter potentials are well-known results since the late 70's, but a detailed and pedagogical calculation of these quantities is hard to find. We derive potentials due to charged and neutral current scattering on electrons, neutrons and protons. Intended readership is for undergraduates/graduates in the fields of relativistic quantum mechanics and quantum field theory. In addition to the derivation of the potentials for neutrinos, we explicitely study the origin of the reversed sign for potentials in the case of antineutrino-scattering.

  16. Neutrino symmetries from high to low scales

    E-Print Network [OSTI]

    Probir Roy

    2007-06-18T23:59:59.000Z

    Proposed symmetry relations, e.g., quark-lepton complementarity (QLC) or tribimaximal mixing (TBM), need to be imposed at a high scale $\\wedge \\sim 10^{12}$ GeV characterising the large masses of right-handed neutrinos required to implement the seesaw mechanism. RG evolution down to the laboratory scale $\\lambda \\sim 10^3$ GeV, generically prone to spoil these relations and their predicted neutrino mixing patterns, can be made to preserve them by appropriately constraining the Majorana phases $\\alpha_{2,3}$. This is explicitly demonstrated in the MSSM for two versions of QLC and two versions of TBM. A preference for $\\alpha_2 \\simeq \\pi$ (i.e. $m_1 \\simeq - m_2$) emerges in each case. Discrimination among the four cases is shown to be possible by future measurements of $\\theta_{13}$.

  17. Double beta decay and neutrino mass models

    E-Print Network [OSTI]

    Helo, J C; Ota, T; Santos, F A Pereira dos

    2015-01-01T23:59:59.000Z

    Neutrinoless double beta decay allows to constrain lepton number violating extensions of the standard model. If neutrinos are Majorana particles, the mass mechanism will always contribute to the decay rate, however, it is not a priori guaranteed to be the dominant contribution in all models. Here, we discuss whether the mass mechanism dominates or not from the theory point of view. We classify all possible (scalar-mediated) short-range contributions to the decay rate according to the loop level, at which the corresponding models will generate Majorana neutrino masses, and discuss the expected relative size of the different contributions to the decay rate in each class. We also work out the phenomenology of one concrete 2-loop model in which both, mass mechanism and short-range diagram, might lead to competitive contributions, in some detail.

  18. Particle physics implications of the WMAP neutrino mass bound

    E-Print Network [OSTI]

    G. Bhattacharyya; H. Päs; L. Song; T. J. Weiler

    2003-04-25T23:59:59.000Z

    The recently published cosmological bound on the absolute neutrino masses obtained from the Wilkinson Microwave Anisotropy Probe (WMAP) data has important consequences for neutrino experiments and models. Taken at face value, the new bound excludes the determination of the absolute neutrino mass in the KATRIN experiment and disfavors a neutrino oscillation interpretation of the LSND experiment. Combined with the KamLAND and Super-K data, the WMAP bound defines an accessible range for the neutrinoless double beta decay amplitude. The bound also impacts the Z-burst annihilation mechanism for resonant generation of extreme-energy cosmic rays on the cosmic neutrino background in two ways: it constrains the local overdensity of neutrino dark matter which is not helpful, but it also limits the resonant energy to a favorable range. In R-parity violating SUSY models neutrino masses are generated by trilinear and bilinear lepton number violating couplings. The WMAP result improves the constraints on these couplings over their existing values by an order of magnitude.

  19. Primordial nucleosynthesis and neutrino physics

    E-Print Network [OSTI]

    Smith, Christel Johanna

    2009-01-01T23:59:59.000Z

    A Brief History of and Introduction to Neutrino Physics . 13Nucleosynthesis and Neutrino Physics A dissertationdensity depend on new neutrino physics in di?erent ways. In

  20. Working group report: Neutrino physics

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    Working group report: Neutrino physics Acknowledgements TheWorking group report: Neutrino physics Coordinators: SANDHYAthe report of the neutrino physics working group at WHEPP-X.

  1. Neutrino physics at accelerators

    E-Print Network [OSTI]

    Enrique Fernandez

    2006-07-16T23:59:59.000Z

    Present and future neutrino experiments at accelerators are mainly concerned with understanding the neutrino oscillation phenomenon and its implications. Here a brief account of neutrino oscillations is given together with a description of the supporting data. Some current and planned accelerator neutrino experiments are also explained.

  2. Muons and Neutrinos 2007

    E-Print Network [OSTI]

    Thomas K. Gaisser

    2008-01-29T23:59:59.000Z

    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.

  3. Optimization of neutrino fluxes for future long baseline neutrino oscillation experiments

    E-Print Network [OSTI]

    Calviani, M; Galymov, V; Velten, P

    2014-01-01T23:59:59.000Z

    One of the main goals of the Long Baseline Neutrino Oscillation experiment (LBNO) experiment is to study the L/E behaviour of the electron neutrino appearance probability in order to determine the unknown phase $\\delta_{CP}$. In the standard neutrino 3-flavour mixing paradigm, this parameter encapsulates a possibility of a CP violation in the lepton sector that in turn could help explain the matter-antimatter asymmetry in the universe. In LBNO, the measurement of $\\delta_{CP}$ would rely on the observation of the electron appearance probability in a broad energy range covering the 1$^{st}$ and 2$^{nd}$ maxima of the oscillation probability. An optimization of the energy spectrum of the neutrino beam is necessary to find the best coverage of the neutrino energies of interest. This in general is a complex task that requires exploring a large parameter space describing hadron target and beamline focusing elements. In this paper we will present a numerical approach of finding a solution to this difficult optimiza...

  4. Neutrino Physics with JUNO

    E-Print Network [OSTI]

    An, Fengpeng; An, Qi; Antonelli, Vito; Baussan, Eric; Beacom, John; Bezrukov, Leonid; Blyth, Simon; Brugnera, Riccardo; Avanzini, Margherita Buizza; 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, Herve; 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; Goger-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, Cecile; 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; Mollenberg, 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, Yifang; Wang, Zhe; Wang, Zheng; Wang, Zhigang; Wang, Zhimin; Wei, Wei; Wen, Liangjian; Wiebusch, Christopher; Wonsak, Bjorn; 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, Frederic; 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

    2015-01-01T23:59:59.000Z

    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plants at 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4 sigma significance with six years of running. The measurement of antineutrino spectrum will also lead to the precise determination of three out of the six oscillation parameters to an accuracy of better than 1\\%. Neutrino burst from a typical cor...

  5. Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes

    E-Print Network [OSTI]

    Ivone F. M. Albuquerque; George F. Smoot

    2001-03-28T23:59:59.000Z

    Neutrino telescopes with large detection volumes can demonstrate that the current indications of neutrino oscillation are correct or if a better description can be achieved with non-standard alternatives. Observations of contained muons produced by atmospheric neutrinos can better constrain the allowed region for oscillations or determine the relevant parameters of non-standard models. We analyze the possibility of neutrino telescopes measuring atmospheric neutrino oscillations. We suggest adjustments to improve this potential. An addition of four densely-instrumented strings to the AMANDA II detector makes observations feasible. Such a configuration is competitive with current and proposed experiments.

  6. Radiatively broken symmetries of nonhierarchical neutrinos

    E-Print Network [OSTI]

    Dighe, Amol; Roy, Probir

    2007-01-01T23:59:59.000Z

    Symmetry-based ideas, such as the quark-lepton complementarity (QLC) principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to explain the observed mixing pattern of neutrinos. We argue that such symmetry relations need to be imposed at a high scale $\\Lambda \\sim 10^{12}$ GeV characterizing the large masses of right-handed neutrinos required to implement the seesaw mechanism. For nonhierarchical neutrinos, renormalisation group evolution down to a laboratory energy scale $\\lambda \\sim 10^3$ GeV tends to radiatively break these symmetries at a significant level and spoil the mixing pattern predicted by them. However, for Majorana neutrinos, suitable constraints on the extra phases $\\alpha_{2,3}$ enable the retention of those high scale mixing patterns at laboratory energies. We examine this issue within the Minimal Supersymmetric Standard Model (MSSM) and demonstrate the fact posited above for two versions of QLC and two versions of TBM. The appropriate constraints are worked out for all these...

  7. Radiatively broken symmetries of nonhierarchical neutrinos

    E-Print Network [OSTI]

    Amol Dighe; Srubabati Goswami; Probir Roy

    2007-09-17T23:59:59.000Z

    Symmetry-based ideas, such as the quark-lepton complementarity (QLC) principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to explain the observed mixing pattern of neutrinos. We argue that such symmetry relations need to be imposed at a high scale $\\Lambda \\sim 10^{12}$ GeV characterizing the large masses of right-handed neutrinos required to implement the seesaw mechanism. For nonhierarchical neutrinos, renormalisation group evolution down to a laboratory energy scale $\\lambda \\sim 10^3$ GeV tends to radiatively break these symmetries at a significant level and spoil the mixing pattern predicted by them. However, for Majorana neutrinos, suitable constraints on the extra phases $\\alpha_{2,3}$ enable the retention of those high scale mixing patterns at laboratory energies. We examine this issue within the Minimal Supersymmetric Standard Model (MSSM) and demonstrate the fact posited above for two versions of QLC and two versions of TBM. The appropriate constraints are worked out for all these four cases. Specifically, a preference for $\\alpha_2 \\approx \\pi$ (i.e. $m_1 \\approx -m_2$) emerges in each case. We also show how a future accurate measurement of $\\theta_{13}$ may enable some discrimination among these four cases in spite of renormalization group evolution.

  8. Neutrino Theory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3, Issue 30Neutrino crossN/SΒ ν

  9. Semi-inclusive charged-current neutrino-nucleus reactions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Moreno, Omar [California State Univ., Los Angeles, CA (United States); Donnelly, T. W. [California State Univ., Los Angeles, CA (United States); Van Orden, Jay Wallace [Old Dominion Univ., Norfolk, VA (United States); Jefferson Lab., Newport News, VA (United States); Ford, William P. [Univ. of Southern Mississippi, Hattiesburg, MS (United States)

    2014-07-01T23:59:59.000Z

    The general, universal formalism for semi-inclusive charged-current (anti)neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case of the hadronic responses, general symmetry principles are invoked to determine which contributions can occur. Finally, the general leptonic-hadronic tensor contraction is given as well as the cross section for the process.

  10. Neutrino masses and mixings in a Minimal S3-invariant Extension of the Standard Model

    SciTech Connect (OSTI)

    Felix, O.; Mondragon, A.; Mondragon, M.; Peinado, E. [Departamento de Fisica Teorica, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 Mexico D.F. (Mexico)

    2007-06-19T23:59:59.000Z

    The mass matrices of the charged leptons and neutrinos, that had been derived in the framework of a Minimal S3-invariant Extension of the Standard Model, are here reparametrized in terms of their eigenvalues. The neutrino mixing matrix, VPMNS, is then computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of the neutrinos and charged leptons are obtained. The reactor, {theta}13, and the atmosferic, {theta}23, mixing angles are found to be functions only of the masses of the charged leptons. The numerical values of {theta}{sub 13}{sup th} and {theta}{sub 23}{sup th} computed from our theoretical expressions are found to be in excellent agreement with the latest experimental determinations. The solar mixing angle, {theta}{sub 12}{sup th}, is found to be a function of both, the charged lepton and neutrino masses, as well as of a Majorana phase {phi}{nu}. A comparison of our theoretical expression for the solar angle {theta}{sub 12}{sup th} with the latest experimental value {theta}{sub 13}{sup exp} {approx_equal} 34 deg. allowed us to fix the scale and origin of the neutrino mass spectrum and obtain the mass values |m{nu}2| = 0.0507eV, |m{nu}1| = 0.0499eV and |m{nu}3| = 0.0193eV, in very good agreement with the observations of neutrino oscillations, the bounds extracted from neutrinoless double beta decay and the precision cosmological measurements of the CMB.

  11. Neutrino masses in SU(4){sub L}?U(1){sub X} gauge models

    SciTech Connect (OSTI)

    Palcu, Adrian [Faculty of Exact Sciences - Aurel Vlaicu University Arad, Str. Elena Dr?goi 2, Arad - 310330 (Romania)

    2013-11-13T23:59:59.000Z

    Neutrino masses are obtained within SU(4){sub L}?U(1){sub X} electroweak gauge models with spontaneous symmetry breaking by simply exploiting the tree level realization of certain dimension-five effective operators. The scalar sector needs not to be enlarged, since these operators are constructed as direct products among scalar multiplets already existing in the model. There is a unique generic matrix for Yukawa couplings in the neutrino sector, while the charged leptons are already in their diagonal basis. The experimentally observed phenomenology in the neutrino sector is obtained as a natural consequence of this particular approach.

  12. Signatures for Right-Handed Neutrinos at the Large Hadron Collider

    SciTech Connect (OSTI)

    Huitu, Katri; Rai, Santosh Kumar [Department of Physics, University of Helsinki and Helsinki Institute of Physics, P.O. Box 64, FIN-00014 University of Helsinki (Finland); Khalil, Shaaban [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No, 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo, 11566 (Egypt); Okada, Hiroshi [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No, 11837, P.O. Box 43 (Egypt)

    2008-10-31T23:59:59.000Z

    We explore possible signatures for right-handed neutrinos in a TeV scale B-L extension of the standard model at the Large Hadron Collider. The studied four lepton signal has a tiny standard model background. We find the signal experimentally accessible at the LHC for the considered parameter regions.

  13. 13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS

    E-Print Network [OSTI]

    13. Neutrino mixing 1 13. NEUTRINO MASS, MIXING, AND OSCILLATIONS Updated May 2012 by K. Nakamura have provided compelling evidences for oscillations of neutrinos caused by nonzero neutrino masses of neutrino oscillations, the phenomenology of neutrino mixing, the problem of the nature - Dirac or Majorana

  14. Reducing cosmological small scale structure via a large dark matter-neutrino interaction: constraints and consequences

    E-Print Network [OSTI]

    Bridget Bertoni; Seyda Ipek; David McKeen; Ann E. Nelson

    2014-12-09T23:59:59.000Z

    Cold dark matter explains a wide range of data on cosmological scales. However, there has been a steady accumulation of evidence for discrepancies between simulations and observations at scales smaller than galaxy clusters. Solutions to these small scale structure problems may indicate that simulations need to improve how they include feedback from baryonic matter, or may imply that dark matter properties differ from the standard cold, noninteracting scenario. One promising way to affect structure formation on small scales is a relatively strong coupling of dark matter to neutrinos. We construct an experimentally viable, simple, renormalizable, model with new interactions between neutrinos and dark matter. We show that addressing the small scale structure problems requires dark matter with a mass that is tens of MeV, and a present-day density determined by an initial particle-antiparticle asymmetry in the dark sector. Generating a sufficiently large dark matter-neutrino coupling requires a new heavy neutrino with a mass around 100 MeV. The heavy neutrino is mostly sterile but has a substantial $\\tau$ neutrino component, while the three nearly massless neutrinos are partly sterile. We provide the first discussion of how such dark matter-neutrino interactions affect neutrino (especially $\\tau$ neutrino) phenomenology. This model can be tested by future astrophysical, particle physics, and neutrino oscillation data. A feature in the neutrino energy spectrum and flavor content from a future nearby supernova would provide strong evidence of neutrino-dark matter interactions. Promising signatures include anomalous matter effects in neutrino oscillations due to nonstandard interactions and a component of the $\\tau$ neutrino with mass around 100 MeV.

  15. Booster Neutrino Experiment - About Neutrinos

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWPSuccess Stories Site MapSolarAbout Neutrinos General Information

  16. Li-loaded directionally sensitive anti-neutrino detector for possible

    E-Print Network [OSTI]

    Mcdonough, William F.

    -3 Aoba, Sendai, 980-8578 Miyagi, Japan. Despite the latent and unique benefits of imaging uranium-loaded neutrino detector. For possible imaging applications, we also explore the feasibility of producing geo-neutrino observations reveal the amount of heavy elements, uranium (U) and thorium (Th), deep inside the earth and can

  17. LC-TH-2003-030 Large lepton avor violating signals in supersymmetric particle

    E-Print Network [OSTI]

    -saw mechanism and by introducing heavy right-handed Majorana neutrinos [6]. In general, a gauge matrices for sleptons and sneutrinos, we demonstrate that large signals are expected. The most general @ M 2 LL M 2y LR M 2 LR M 2 RR 1 A ; (1) 2 #12; where the entries are 3 #2; 3 matrices. They are given

  18. Solar neutrino physics: Sensitivity to light dark matter particles

    E-Print Network [OSTI]

    Ilidio Lopes; Joseph Silk

    2013-09-29T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    Reddy, Sanjay

    2013-09-06T23:59:59.000Z

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

  20. From the Fourth Color to Spin-charge Separation - Neutrinos and Spinons

    E-Print Network [OSTI]

    Chi Xiong

    2015-03-31T23:59:59.000Z

    We introduce the spin-charge separation mechanism to the quark-lepton unification models which consider the lepton number as the fourth color. In certain finite-density systems, quarks and leptons are decomposed into spinons and chargons, which carry the spin and charge degrees of freedom respectively. Neutrinos can be related to the spinons with respect to the electric-charge and spin separation in the early universe or other circumstances. Some effective, probably universal couplings between the spinon sector and the chargon sector are derived and a phenomenological description for the chargon condensate is proposed. It is then demonstrated that the spinon current can induce vorticity in the chargon condensate, and spinon zero modes are trapped in the vortices, forming spinon-vortex bound states. In cosmology this configuration may lead to the emission of extremely high energy neutrinos when vortices split and reconnect.

  1. From the Fourth Color to Spin-charge Separation - Neutrinos and Spinons

    E-Print Network [OSTI]

    Xiong, Chi

    2015-01-01T23:59:59.000Z

    We introduce the spin-charge separation mechanism to the quark-lepton unification models which consider the lepton number as the fourth color. In certain finite-density systems, quarks and leptons are decomposed into spinons and chargons, which carry the spin and charge degrees of freedom respectively. Neutrinos can be related to the spinons with respect to the electric-charge and spin separation in the early universe or other circumstances. Some effective, probably universal couplings between the spinon sector and the chargon sector are derived and a phenomenological description for the chargon condensate is proposed. It is then demonstrated that the spinon current can induce vorticity in the chargon condensate, and spinon zero modes are trapped in the vortices, forming spinon-vortex bound states. In cosmology this configuration may lead to the emission of extremely high energy neutrinos when vortices split and reconnect.

  2. Threshold effects on renormalization group running of neutrino parameters in the low-scale seesaw model

    E-Print Network [OSTI]

    Johannes Bergstrom; Tommy Ohlsson; He Zhang

    2011-04-04T23:59:59.000Z

    We show that, in the low-scale type-I seesaw model, renormalization group running of neutrino parameters may lead to significant modifications of the leptonic mixing angles in view of so-called seesaw threshold effects. Especially, we derive analytical formulas for radiative corrections to neutrino parameters in crossing the different seesaw thresholds, and show that there may exist enhancement factors efficiently boosting the renormalization group running of the leptonic mixing angles. We find that, as a result of the seesaw threshold corrections to the leptonic mixing angles, various flavor symmetric mixing patterns (e.g., bi-maximal and tri-bimaximal mixing patterns) can be easily accommodated at relatively low energy scales, which is well within the reach of running and forthcoming experiments (e.g., the LHC).

  3. Experimental Neutrino Physics: Final Report

    SciTech Connect (OSTI)

    Lane, Charles E.; Maricic, Jelena

    2012-09-05T23:59:59.000Z

    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.

  4. Gauge Theory Model of the Neutrino and New Physics Beyond the Standard Model

    E-Print Network [OSTI]

    Yue-Liang Wu

    2012-03-05T23:59:59.000Z

    Majorana features of neutrinos and SO(3) gauge symmetry of three families enable us to construct a gauge model of neutrino for understanding naturally the observed smallness of neutrino masses and the nearly tri-bimaximal neutrino mixing when combining together with the mechanism of approximate global U(1) family symmetry. The vacuum structure of SO(3) symmetry breaking is found to play an important role. The mixing angle $\\theta_{13}$ and CP-violating phases governed by the vacuum of spontaneous symmetry breaking are in general non-zero and testable experimentally at the allowed sensitivity. The model predicts the existence of vector-like SO(3) triplet charged leptons and vector-like SO(3) triplet Majorana neutrinos as well as SO(3) tri-triplet Higgs bosons, some of them can be light and explored at the colliders LHC and ILC.

  5. SO(3) Gauge Symmetry and Nearly Tri-bimaximal Neutrino Mixing

    E-Print Network [OSTI]

    Yue-Liang Wu

    2008-07-24T23:59:59.000Z

    In this note I mainly focus on the neutrino physics part in my talk and report the most recent progress made in \\cite{YLW0}. It is seen that the Majorana features of neutrinos and SO(3) gauge flavor symmetry can simultaneously explain the smallness of neutrino masses and nearly tri-bimaximal neutrino mixing when combining together with the mechanism of approximate global U(1) family symmetry. The mixing angle $\\theta_{13}$ and CP-violating phase are in general nonzero and testable experimentally at the allowed sensitivity. The model also predicts the existence of vector-like Majorana neutrinos and charged leptons as well as new Higgs bosons, some of them can be light and explored at the LHC and ILC.

  6. Measurable neutrino mass scale in A{sub 4}xSU(5)

    SciTech Connect (OSTI)

    Antusch, S.; Spinrath, M. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Muenchen (Germany); King, Stephen F. [School of Physics and Astronomy, University of Southampton, SO17 1BJ Southampton (United Kingdom)

    2011-01-01T23:59:59.000Z

    We propose a supersymmetric A{sub 4}xSU(5) model of quasidegenerate neutrinos which predicts the effective neutrino mass m{sub ee} relevant for neutrinoless double beta decay to be proportional to the neutrino mass scale, thereby allowing its determination approximately independently of unknown Majorana phases. Such a natural quasidegeneracy is achieved by using A{sub 4} family symmetry (as an example of a non-Abelian family symmetry with real triplet representations) to enforce a contribution to the neutrino mass matrix proportional to the identity. Tribimaximal neutrino mixing as well as quark CP violation with {alpha}{approx_equal}90 deg. d a leptonic CP phase {delta}{sub MNS{approx_equal}}90 deg. arise from the breaking of the A{sub 4} family symmetry by the vacuum expectation values of four 'flavon' fields pointing in specific postulated directions in flavor space.

  7. Neutrino Physics at Fermilab

    ScienceCinema (OSTI)

    Niki Saoulidou

    2010-01-08T23:59:59.000Z

    Neutrino oscillations provide the first evidence for physics beyond the Standard Model. I will briefly overview the neutrino "hi-story", describing key discoveries over the past decades that shaped our understanding of neutrinos and their behavior. Fermilab was, is and hopefully will be at the forefront of the accelerator neutrino experiments.  NuMI, the most powerful accelerator neutrino beam in the world has ushered us into the era of precise measurements. Its further upgrades may give a chance to tackle the remaining mysteries of the neutrino mass hierarchy and possible CP violation.

  8. Testing Radiative Neutrino Mass Models at the LHC

    E-Print Network [OSTI]

    Yi Cai; Jackson D. Clarke; Michael A. Schmidt; Raymond R. Volkas

    2015-02-07T23:59:59.000Z

    The Large Hadron Collider provides us new opportunities to search for the origin of neutrino mass. Beyond the minimal see-saw models a plethora of models exist which realise neutrino mass at tree- or loop-level, and it is important to be sure that these possibilities are satisfactorily covered by searches. The purpose of this paper is to advance a systematic approach to this problem. Majorana neutrino mass models can be organised by SM-gauge-invariant operators which violate lepton number by two units. In this paper we write down the minimal ultraviolet completions for all of the mass-dimension 7 operators. We predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged scalar, and a scalar doublet, whose properties are constrained by neutrino oscillation data. A detailed collider study is presented for $O_3=LLQ\\bar dH$ and $O_8 = L\\bar d\\bar e^\\dagger \\bar u^\\dagger H$ completions with a vector-like quark $\\chi\\sim(3, 2, -\\frac{5}{6})$ and a leptoquark $\\phi\\sim(\\bar 3,1,\\frac{1}{3})$. The existing LHC limits extracted from searches for vector-like fermions and sbottoms/stops are $m_\\chi \\gtrsim 620$ GeV and $m_\\phi\\gtrsim 600$ GeV.

  9. Study of Two-Loop Neutrino Mass Generation Models

    E-Print Network [OSTI]

    Geng, Chao-Qiang

    2015-01-01T23:59:59.000Z

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

  10. Running Effects on Lepton Mixing Angles in Flavour Models with Type I Seesaw

    E-Print Network [OSTI]

    Yin Lin; Luca Merlo; Alessio Paris

    2009-11-27T23:59:59.000Z

    We study renormalization group running effects on neutrino mixing patterns when a (type I) seesaw model is implemented by suitable flavour symmetries. We are particularly interested in mass-independent mixing patterns to which the widely studied tribimaximal mixing pattern belongs. In this class of flavour models, the running contribution from neutrino Yukawa coupling, which is generally dominant at energies above the seesaw threshold, can be absorbed by a small shift on neutrino mass eigenvalues leaving mixing angles unchanged. Consequently, in the whole running energy range, the change in mixing angles is due to the contribution coming from charged lepton sector. Subsequently, we analyze in detail these effects in an explicit flavour model for tribimaximal neutrino mixing based on an A4 discrete symmetry group. We find that for normally ordered light neutrinos, the tribimaximal prediction is essentially stable under renormalization group evolution. On the other hand, in the case of inverted hierarchy, the deviation of the solar angle from its TB value can be large depending on mass degeneracy.

  11. The Neutrino Mass Hierarchy from Nuclear Reactor Experiments

    E-Print Network [OSTI]

    Emilio Ciuffoli; Jarah Evslin; Xinmin Zhang

    2013-08-14T23:59:59.000Z

    10 years from now reactor neutrino experiments will attempt to determine which neutrino mass eigenstate is the most massive. In this letter we present the results of more than seven million detailed simulations of such experiments, studying the dependence of the probability of successfully determining the mass hierarchy upon the analysis method, the neutrino mass matrix parameters, reactor flux models, geoneutrinos and, in particular, combinations of baselines. We show that a recently reported spurious dependence of the data analysis upon the high energy tail of the reactor spectrum can be removed by using a weighted Fourier transform. We determine the optimal baselines and corresponding detector locations. For most values of the CP-violating, leptonic Dirac phase delta, a degeneracy prevents NOvA and T2K from determining either delta or the hierarchy. We determine the confidence with which a reactor experiment can determine the hierarchy, breaking the degeneracy.

  12. Loop-induced Neutrino Masses: A Case Study

    E-Print Network [OSTI]

    Geng, Chao-Qiang; Tsai, Lu-Hsing

    2014-01-01T23:59:59.000Z

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

  13. Breaking the symmetries of the bulb model in two-dimensional self-induced supernova neutrino flavor conversions

    E-Print Network [OSTI]

    Mirizzi, Alessandro

    2015-01-01T23:59:59.000Z

    Self-induced flavor conversions of supernova (SN) neutrinos have been characterized in the spherically symmetric "bulb model", reducing the neutrino evolution to a one dimensional problem along a radial direction. We lift this assumption, presenting a two-dimensional model where neutrinos are launched from a spherical neutrino-sphere with many zenithal angles and two azimuthal angles. We also assume that self-induced conversions are not suppressed by large matter effects. In this situation we find that self-interacting neutrinos spontaneously break axial and spherical symmetries. As a result the flavor content and the lepton number of the neutrino gas would acquire seizable direction-dependent variations, breaking the coherent behavior found in the spherically symmetric case. This finding would suggest that the previous results of the self-induced flavor evolution obtained in one-dimensional models should be critically re-examined.

  14. A Measurement of the Appearance of Atmospheric Tau Neutrinos by Super-Kamiokande

    E-Print Network [OSTI]

    ,

    2013-01-01T23:59:59.000Z

    Super-Kamiokande atmospheric neutrino data were fit with an un-binned maximum likelihood method to search for the appearance of tau leptons resulting from the interactions of oscillation-generated tau neutrinos in the detector. Relative to the expectation of unity, the tau normalization is found to be $1.42 \\pm 0.35 \\ (stat)^{+0.14}_{-0.12}\\ (sys) $ excluding the no-tau-appearance hypothesis, for which the normalization would be zero, at the 3.8$\\sigma$ level. We estimate that $180.1 \\pm 44.3\\ (stat)^{+17.8}_{-15.2}\\ (sys)$ tau leptons were produced in the fiducial volume of the detector by tau neutrinos during the running period, compared to an expectation of $120.2^{+34.2}_{-34.8}\\ (sys)$ events.

  15. Renormalization group running of neutrino parameters in the inverse seesaw model

    E-Print Network [OSTI]

    Johannes Bergstrom; Michal Malinsky; Tommy Ohlsson; He Zhang

    2012-07-06T23:59:59.000Z

    We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.

  16. Renormalization group running of neutrino parameters in the inverse seesaw model

    SciTech Connect (OSTI)

    Bergstroem, Johannes; Malinsky, Michal; Ohlsson, Tommy; Zhang He [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH)-AlbaNova University Center, Roslagstullsbacken 21, 106 91 Stockholm (Sweden)

    2010-06-01T23:59:59.000Z

    We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.

  17. Pseudo-Dirac neutrinos in the new standard model

    SciTech Connect (OSTI)

    Gouvea, Andre de; Huang, W.-C.; Jenkins, James [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States); Elementary Particles and Field Theory Group, MS B285, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

    2009-10-01T23:59:59.000Z

    The addition of gauge-singlet fermions to the standard model Lagrangian renders the neutrinos massive and allows one to explain all that is experimentally known about neutrino masses and lepton mixing by varying the values of the Majorana mass parameters M for the gauge singlets and the neutrino Yukawa couplings {lambda}. Here we explore the region of parameter space where M values are much smaller than the neutrino Dirac masses {lambda}v. In this region, neutrinos are pseudo-Dirac fermions. We find that current solar data constrain M values to be less than at least 10{sup -9} eV, and discuss the sensitivity of future experiments to tiny gauge-singlet fermion masses. We also discuss a useful basis for analyzing pseudo-Dirac neutrino mixing effects. In particular, we identify a simple relationship between elements of M and the induced enlarged mixing matrix and new mass-squared differences. These allow one to directly relate bounds on the new mass-squared differences to bounds on the singlet fermion Majorana masses.

  18. Non standard neutrino interactions

    E-Print Network [OSTI]

    Miranda, O G

    2015-01-01T23:59:59.000Z

    Neutrino oscillations have become well-known phenomenon; the measurements of neutrino mixing angles and mass squared differences are continuously improving. Future oscillation experiments will eventually determine the remaining unknown neutrino parameters, namely, the mass ordering, normal or inverted, and the CP-violating phase. On the other hand, the absolute mass scale of neutrinos could be probed by cosmological observations, single beta decay as well as by neutrinoless double beta decay experiments. Furthermore, the last one may shed light on the nature of neutrinos, Dirac or Majorana, by measuring the effective Majorana mass of neutrinos. However, the neutrino mass generation mechanism remains unknown. A well-motivated phenomenological approach to search for new physics, in the neutrino sector, is that of non-standard interactions. In this short review, the current constraints in this picture, as well as the perspectives from future experiments, are discussed.

  19. Estimations of baryon asymmetry for different neutrino mass models

    E-Print Network [OSTI]

    Amal Kr. Sarma; Hijam Zeen Devi; N. Nimai Singh

    2006-04-05T23:59:59.000Z

    We present a comparison of the numerical prediction on baryon asymmetry of the Universe in different neutrino mass models. We start with a very brief review on the main formalism of baryogenesis via leptogenesis through decay of heavy right-handed Majorana neutrinos, and then calculate the baryon asymmetry of the universe for known six neutrino mass models viz., three quasi-degenerate, two inverted and one normal hierarchical models, which are derived from canonical seesaw formula. The corresponding mass matrices for the right-handed Majorana neutrino as well as the Dirac neutrino, which are fixed at the seesaw stage for generating correct light neutrino mass matrices, are again employed in the calculation of baryogenesis. This procedure removes possible ambiguity on the choices of Dirac neutrino and right-handed Majorana mass matrices, and fixes input parameters at the seesaw stage. We find that the ranges of predictions from both normal hierarchical model and degenerate model (DegT1A) are almost consistent with the observed baryon asymmetry of the universe. Combining the present result with other predictions such as light neutrino masses and mixing angles, and stability under radiative corrections in MSSM, the normal hierarchical model appears to be the most favourable choice of nature.

  20. Introduction to Neutrino Physics

    SciTech Connect (OSTI)

    Linares, Edgar Casimiro [Division de Ciencias e Ingenierias Campus Leon, Loma del Bosque 103 Col. Lomas del Campestre, C.P. 37150 Leon (Mexico) and Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Av. Complutense, 22, C.P. 28040, Madrid (Spain)

    2009-04-30T23:59:59.000Z

    I present a basic introduction to the physics of the neutrino, with emphasis on experimental results and developments.

  1. Solar neutrinos - Eclipse effect

    E-Print Network [OSTI]

    Mohan Narayan; G. Rajasekaran; Rahul Sinha

    1997-03-12T23:59:59.000Z

    It is pointed out that the enhancement of the solar neutrino rate in a real time detector like Super-Kamioka, SNO or Borexino due to neutrino oscillations in the moon during a partial or total solar eclipse may be observable. The enhancement is calculated as a function of the neutrino parameters in the case of three flavor mixing. This enhancement if seen, can further help to determine the neutrino parameters.

  2. Recent results from the UrQMD hybrid model for heavy ion collisions

    E-Print Network [OSTI]

    Bleicher, Marcus; Steinheimer, Jan; van Hees, Hendrik

    2015-01-01T23:59:59.000Z

    These proceedings present recent results from transport-hydrodynamics-hybrid models for heavy ion collisions at relativistic energies. The main focus is on the absorption of (anti-)protons in the hadronic afterburner stage of the reaction, di-lepton production at SPS and heavy quark dynamics.

  3. Small mixing angle {theta}{sub 13} and the lepton asymmetry

    SciTech Connect (OSTI)

    Lee, Song-Haeng; Siyeon, Kim [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2005-05-01T23:59:59.000Z

    We present the correlation of low-energy CP phases, both Dirac and Majorana, and the lepton asymmetry for the baryon asymmetry in the universe, with a certain class of Yukawa matrices that consist of two right-handed neutrinos whose mass ratio is about 2x10{sup -4} and include one texture zero in themselves. For cases in which the amount of the lepton asymmetry Y{sub L} turns out to be proportional to {theta}{sub 13}{sup 2}, we consider the constraint between two types of CP phases and the relation of Y{sub L} versus the Jarlskog invariant or the amplitude of neutrinoless double beta decay as {theta}{sub 13} varies.

  4. Semi-leptonic Decay of Lambda-b in the Standard Model and with New Physics

    E-Print Network [OSTI]

    Wanwei Wu

    2015-05-13T23:59:59.000Z

    Heavy quark decays provide a very advantageous investigation to test the Standard Model (SM). Recently, promising experiments with \\textit{b} quark, as well as the analysis of the huge data sets produced at the B factories, have led to an increasing study and sensitive measurements of relative \\textit{b} quark decays. In this thesis, I calculate various observables in the semi-leptonic decay process $\\Lambda_{b}\\to \\Lambda_{c}\\tau\\bar{\

  5. Constraining Sterile Neutrinos Using Reactor Neutrino Experiments

    E-Print Network [OSTI]

    Ivan Girardi; Davide Meloni; Tommy Ohlsson; He Zhang; Shun Zhou

    2014-08-21T23:59:59.000Z

    Models of neutrino mixing involving one or more sterile neutrinos have resurrected their importance in the light of recent cosmological data. In this case, reactor antineutrino experiments offer an ideal place to look for signatures of sterile neutrinos due to their impact on neutrino flavor transitions. In this work, we show that the high-precision data of the Daya Bay experi\\-ment constrain the 3+1 neutrino scenario imposing upper bounds on the relevant active-sterile mixing angle $\\sin^2 2 \\theta_{14} \\lesssim 0.06$ at 3$\\sigma$ confidence level for the mass-squared difference $\\Delta m^2_{41}$ in the range $(10^{-3},10^{-1}) \\, {\\rm eV^2}$. The latter bound can be improved by six years of running of the JUNO experiment, $\\sin^22\\theta_{14} \\lesssim 0.016$, although in the smaller mass range $ \\Delta m^2_{41} \\in (10^{-4} ,10^{-3}) \\, {\\rm eV}^2$. We have also investigated the impact of sterile neutrinos on precision measurements of the standard neutrino oscillation parameters $\\theta_{13}$ and $\\Delta m^2_{31}$ (at Daya Bay and JUNO), $\\theta_{12}$ and $\\Delta m^2_{21}$ (at JUNO), and most importantly, the neutrino mass hierarchy (at JUNO). We find that, except for the obvious situation where $\\Delta m^2_{41}\\sim \\Delta m^2_{31}$, sterile states do not affect these measurements substantially.

  6. Neutrino Oscillations and the Solar Neutrino Problem

    E-Print Network [OSTI]

    W. C. Haxton

    2000-04-28T23:59:59.000Z

    I describe the current status of the solar neutrino problem, summarizing the arguments that its resolution will require new particle physics. The phenomenon of matter-enhanced neutrino oscillations is reviewed. I consider the implications of current experiments -- including the SuperKamiokande atmospheric and LSND measurements -- and the need for additional constraints from SNO and other new detectors.

  7. Neutrino Observations from the Sudbury Neutrino Observatory

    E-Print Network [OSTI]

    A. W. P. Poon; for the SNO Collaboration

    2001-10-07T23:59:59.000Z

    The Sudbury Neutrino Observatory (SNO) is a water imaging Cherenkov detector. Its usage of 1000 metric tons of D$_{2}$O as target allows the SNO detector to make a solar-model independent test of the neutrino oscillation hypothesis by simultaneously measuring the solar $\

  8. Neutrino Nuclear Responses For Neutrino Studies In Nuclear Femto Laboratories

    SciTech Connect (OSTI)

    Ejiri, H. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047, Japan and Nuclear Science, Czech Technical University, Brehova, Prague (Czech Republic)

    2011-12-16T23:59:59.000Z

    Neutrinos are key particles for particle and astro-nuclear physics. Majorana neutrino masses and phases, solar and supernova neutrino productions and oscillations, and neutrino nuclear synthesis and fundamental weak interactions are well studied in nuclei as femto laboratories. Here neutrino nuclear responses are crucial for the neutrino studies. This reports briefly experimental studies of neutrino nuclear responses, charge exchange reactions on Ga to study nuclear responses for solar and {sup 51}Cr neutrinos, and {beta}{sup +} neutrino responses for {beta}{beta}-{nu} matrix elements and astro {nu} interactions by photon and muon probes.

  9. Status of Neutrino Oscillations

    E-Print Network [OSTI]

    J. W. F. Valle

    2001-04-04T23:59:59.000Z

    Solar and atmospheric neutrino data require physics beyond the Standard Model of particle physics. The simplest, most generic, but not yet unique, interpretation of the data is in terms of neutrino oscillations. I summarize the results of the latest three-neutrino oscillation global fit of the data, in particular the bounds on the angle $\\theta_{13}$ probed in reactor experiments. Even though not implied by the data, bi-maximal neutrino mixing emerges as an attractive possibility either in hierarchical or quasi-degenerate neutrino scenarios.

  10. Search for lepton-family-number nonconservation

    SciTech Connect (OSTI)

    Hoffman, C.M.

    1986-01-01T23:59:59.000Z

    A review of the status of lepton-family-number nonconservation is given. After a brief historical and theoretical discussion, a description of how experimental searches for lepton-family-number nonconservation are performed is presented. Finally, a summary of the results from past experiments and prospects for future experiments is given.

  11. SNO Data: Results from Experiments at the Sudbury Neutrino Observatory

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Sudbury Neutrino Observatory (SNO) was built 6800 feet under ground, in INCO's Creighton mine near Sudbury, Ontario. SNO is a heavy-water Cherenkov detector that is designed to detect neutrinos produced by fusion reactions in the sun. It uses 1000 tonnes of heavy water, on loan from Atomic Energy of Canada Limited (AECL), contained in a 12 meter diameter acrylic vessel. Neutrinos react with the heavy water (D2O) to produce flashes of light called Cherenkov radiation. This light is then detected by an array of 9600 photomultiplier tubes mounted on a geodesic support structure surrounding the heavy water vessel. The detector is immersed in light (normal) water within a 30 meter barrel-shaped cavity (the size of a 10 story building!) excavated from Norite rock. Located in the deepest part of the mine, the overburden of rock shields the detector from cosmic rays. The detector laboratory is extremely clean to reduce background signals from radioactive elements present in the mine dust which would otherwise hide the very weak signal from neutrinos. (From http://www.sno.phy.queensu.ca/]

    The SNO website provides access to various datasets. See also the SNO Image Catalog at http://www.sno.phy.queensu.ca/sno/images/ and computer-generated images of SNO events at http://www.sno.phy.queensu.ca/sno/events/ and the list of published papers.

  12. Democratic Neutrino Theory

    E-Print Network [OSTI]

    Dmitry Zhuridov

    2014-05-21T23:59:59.000Z

    New theory of neutrino masses and mixing is introduced. This theory is based on a simple S_3 symmetric democratic neutrino mass matrix, and predicts the neutrino mass spectrum of normal ordering. Taking into account the matter effect and proper averaging of the oscillations, this theory agrees with the variety of atmospheric, solar and accelerator neutrino data. Moreover, the absolute scale of the neutrino masses m of 0.03 eV is determined in this theory, using the atmospheric neutrino oscillation data. In case of tiny perturbations in the democratic mass matrix only one this scale parameter m allows to explain the mentioned above neutrino results, and the theory has huge predictive power.

  13. Effect of steriles states on lepton magnetic moments and neutrinoless double beta decay

    E-Print Network [OSTI]

    Abada, A; Teixeira, A M

    2014-01-01T23:59:59.000Z

    We address the impact of sterile fermion states on the anomalous magnetic moment of charged leptons, as well as their contribution to neutrinoless double beta decays. We illustrate our results in a minimal, effective extension of the Standard Model by one sterile fermion state, and in a well-motivated framework of neutrino mass generation, embedding the Inverse Seesaw into the Standard Model. The simple "3+1" effective case succeeds in alleviating the tension related to the muon anomalous magnetic moment, albeit only at the 3$\\sigma$ level, and for light sterile states (corresponding to a }cosmologically disfavoured regime). Interestingly, our analysis shows that a future $0 \

  14. Compromise between neutrino masses and collider signatures in the type-II seesaw model

    SciTech Connect (OSTI)

    Chao Wei; Luo Shu; Xing Zhizhong; Zhou Shun [Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, Beijing 100049 (China)

    2008-01-01T23:59:59.000Z

    A natural extension of the standard SU(2){sub L}xU(1){sub Y} gauge model to accommodate massive neutrinos is to introduce one Higgs triplet and three right-handed Majorana neutrinos, leading to a 6x6 neutrino mass matrix which contains three 3x3 submatrices, M{sub L}, M{sub D} and M{sub R}. We show that three light Majorana neutrinos (i.e., the mass eigenstates of {nu}{sub e}, {nu}{sub {mu}}, and {nu}{sub {tau}}) are exactly massless in this model, if and only if M{sub L}=M{sub D}M{sub R}{sup -1}M{sub D}{sup T} exactly holds. This no-go theorem implies that small but nonvanishing neutrino masses may result from a significant but incomplete cancellation between M{sub L} and M{sub D}M{sub R}{sup -1}M{sub D}{sup T} terms in the Type-II seesaw formula, provided three right-handed Majorana neutrinos are of O(1) TeV and experimentally detectable at the LHC. We propose three simple Type-II seesaw scenarios with the A{sub 4}xU(1){sub X} flavor symmetry and its explicit breaking to interpret the observed neutrino mass spectrum and neutrino mixing pattern. Such a TeV-scale neutrino model can be tested in two complementary ways: (1) searching for possible collider signatures of lepton number violation induced by the right-handed Majorana neutrinos and doubly-charged Higgs particles; and (2) searching for possible consequences of unitarity violation of the 3x3 neutrino mixing matrix in the future long-baseline neutrino oscillation experiments.

  15. Neutrino Oscillations Physics 135c

    E-Print Network [OSTI]

    Golwala, Sunil

    Neutrino Oscillations Gary Cheng Physics 135c 6/1/07 #12;Introduction: Theory Neutrinos have mass neutrinos are produced. The difference between the mass eigenstates and the flavor eigenstates of neutrinos is what causes neutrino oscillations. #12;Introduction: Theory 2 The mass eigenstates 1, 2, 3

  16. Collective neutrino oscillations in supernovae

    SciTech Connect (OSTI)

    Duan, Huaiyu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-06-24T23:59:59.000Z

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

  17. A New Neutrino Oscillation

    SciTech Connect (OSTI)

    Parke, Stephen J.; /Fermilab

    2011-07-01T23:59:59.000Z

    Starting in the late 1960s, neutrino detectors began to see signs that neutrinos, now known to come in the flavors electron ({nu}{sub e}), muon ({nu}{sub {mu}}), and tau ({nu}{sub {tau}}), could transform from one flavor to another. The findings implied that neutrinos must have mass, since massless particles travel at the speed of light and their clocks, so to speak, don't tick, thus they cannot change. What has since been discovered is that neutrinos oscillate at two distinct scales, 500 km/GeV and 15,000 km/GeV, which are defined by the baseline (L) of the experiment (the distance the neutrino travels) divided by the neutrino energy (E). Neutrinos of one flavor can oscillate into neutrinos of another flavor at both L/E scales, but the amplitude of these oscillations is different for the two scales and depends on the initial and final flavor of the neutrinos. The neutrino states that propogate unchanged in time, the mass eigenstates {nu}1, {nu}2, {nu}3, are quantum mechanical mixtures of the electron, muon, and tau neutrino flavors, and the fraction of each flavor in a given mass eigenstate is controlled by three mixing angles and a complex phase. Two of these mixing angles are known with reasonable precision. An upper bound exists for the third angle, called {theta}{sub 13}, which controls the size of the muon neutrino to electron neutrino oscillation at an L/E of 500 km/GeV. The phase is completely unknown. The existence of this phase has important implications for the asymmetry between matter and antimatter we observe in the universe today. Experiments around the world have steadily assembled this picture of neutrino oscillation, but evidence of muon neutrino to electron neutrino oscillation at 500 km/GeV has remained elusive. Now, a paper from the T2K (Tokai to Kamioka) experiment in Japan, reports the first possible observation of muon neutrinos oscillating into electron neutrinos at 500 km/GeV. They see 6 candidate signal events, above an expected background of 1.5 events. The probability that the 6 events are all background is only about 0.7%. Stated differently, this is a 2.7{sigma} indication that the parameter that controls the oscillation, the neutrino mixing angle {theta}{sub 13}, is nonzero, just shy of the 3{sigma} requirement to claim 'evidence for.' Nevertheless, this experiment provides the strongest indication to date that this oscillation actually occurs in nature.

  18. arXiv:hep-ph/0412300v121Dec2004 Neutrinoless double beta decay and direct searches for neutrino mass

    E-Print Network [OSTI]

    Piepke, Andreas G.

    arXiv:hep-ph/0412300v121Dec2004 Neutrinoless double beta decay and direct searches for neutrino (Dated: December 22, 2004) Study of the neutrinoless double beta decay and searches for the manifestation and recommendations on them. · Observation of the neutrinoless double-beta decay (0) would prove that the total lepton

  19. Spontaneous R-Parity Breaking, Stop LSP Decays and the Neutrino Mass Hierarchy

    E-Print Network [OSTI]

    Zachary Marshall; Burt A. Ovrut; Austin Purves; Sogee Spinner

    2014-06-03T23:59:59.000Z

    The MSSM with right-handed neutrino supermultiplets, gauged B-L symmetry and a non-vanishing sneutrino expectation value is the minimal theory that spontaneously breaks R-parity and is consistent with the bounds on proton stability and lepton number violation. This minimal B-L MSSM can have a colored/charged LSP, of which a stop LSP is the most amenable to observation at the LHC. We study the R-parity violating decays of a stop LSP into a bottom quark and charged leptons--the dominant modes for a generic "admixture" stop. A numerical analysis of the relative branching ratios of these decay channels is given using a wide scan over the parameter space. The fact that R-parity is violated in this theory by a vacuum expectation value of a sneutrino links these branching ratios directly to the neutrino mass hierarchy. It is shown how a discovery of bottom-charged lepton events at the LHC can potentially determine whether the neutrino masses are in a normal or inverted hierarchy, as well as determining the theta_23 neutrino mixing angle. Finally, present LHC bounds on these leptoquark signatures are used to put lower bounds on the stop mass.

  20. Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS

    E-Print Network [OSTI]

    Agarwalla, Sanjib Kumar; Prakash, Suprabh

    2014-01-01T23:59:59.000Z

    A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity to the measurement of CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 4sigma sensitivity to CP violation for 59% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 4sigma sensitivity for 51% of true values of deltaCP. On the other hand, for the discovery of a...

  1. Atmospheric neutrino oscillations and tau neutrinos in ice

    E-Print Network [OSTI]

    Gerardo Giordano; Olga Mena; Irina Mocioiu

    2010-04-20T23:59:59.000Z

    The main goal of the IceCube Deep Core Array is to search for neutrinos of astrophysical origins. Atmospheric neutrinos are commonly considered as a background for these searches. We show here that cascade measurements in the Ice Cube Deep Core Array can provide strong evidence for tau neutrino appearance in atmospheric neutrino oscillations. A careful study of these tau neutrinos is crucial, since they constitute an irreducible background for astrophysical neutrino detection.

  2. Fourth standard model family neutrino at future linear colliders

    SciTech Connect (OSTI)

    Ciftci, A.K.; Ciftci, R.; Sultansoy, S. [Physics Department, Faculty of Sciences, Ankara University, 06100 Tandogan, Ankara (Turkey); Physics Department, Faculty of Sciences and Arts, Gazi University, 06500 Teknikokullar, Ankara (Turkey)

    2005-09-01T23:59:59.000Z

    It is known that flavor democracy favors the existence of the fourth standard model (SM) family. In order to give nonzero masses for the first three-family fermions flavor democracy has to be slightly broken. A parametrization for democracy breaking, which gives the correct values for fundamental fermion masses and, at the same time, predicts quark and lepton Cabibbo-Kobayashi-Maskawa (CKM) matrices in a good agreement with the experimental data, is proposed. The pair productions of the fourth SM family Dirac ({nu}{sub 4}) and Majorana (N{sub 1}) neutrinos at future linear colliders with {radical}(s)=500 GeV, 1 TeV, and 3 TeV are considered. The cross section for the process e{sup +}e{sup -}{yields}{nu}{sub 4}{nu}{sub 4}(N{sub 1}N{sub 1}) and the branching ratios for possible decay modes of the both neutrinos are determined. The decays of the fourth family neutrinos into muon channels ({nu}{sub 4}(N{sub 1}){yields}{mu}{sup {+-}}W{sup {+-}}) provide cleanest signature at e{sup +}e{sup -} colliders. Meanwhile, in our parametrization this channel is dominant. W bosons produced in decays of the fourth family neutrinos will be seen in detector as either di-jets or isolated leptons. As an example, we consider the production of 200 GeV mass fourth family neutrinos at {radical}(s)=500 GeV linear colliders by taking into account di-muon plus four jet events as signatures.

  3. Experimental Neutrino Physics

    E-Print Network [OSTI]

    Christopher W. Walter

    2008-10-22T23:59:59.000Z

    It's been a remarkable decade in neutrino physics. Ten years ago this summer, at the 1998 neutrino conference in Takayama, the Super-Kamiokande collaboration reported the observation of neutrinos changing flavor, thereby establishing the existence of neutrino mass. A few years later, the SNO experiment solved the long-standing solar neutrino problem demonstrating that it too was due to neutrino oscillation. Just a few years after that, these effects were confirmed and the oscillation parameters were measured with man-made neutrino sources. Now, just in this last year, the same neutrinos which were the source of the 30 year old solar neutrino problem were measured for the first time in a real-time experiment. In this talk, I will explain how a set of experiments, especially ones in the last few years, have established a consistent framework of neutrino physics and also explain some outstanding questions. Finally, I will cover how a set of upcoming experiments hope to address these questions in the coming decade.

  4. SuperGZK neutrinos

    E-Print Network [OSTI]

    V. Berezinsky

    2005-09-22T23:59:59.000Z

    The sources and fluxes of superGZK neutrinos, $E>10^{20}$ eV, are discussed. The fluxes of {\\em cosmogenic neutrinos}, i.e. those produced by ultra-high energy cosmic rays (UHECR) interacting with CMB photons, are calculated in the models, which give the good fit to the observed flux of UHECR. The best fit given in no-evolutionary model with maximum acceleration energy $E_{\\rm max}=1\\times 10^{21}$ eV results in very low flux of superGZK neutrinos an order of magnitude lower than the observed flux of UHECR. The predicted neutrino flux becomes larger and observable by next generation detectors at energies $10^{20} - 10^{21}$ eV in the evolutionary models with $E_{\\rm max}=1\\times 10^{23}$ eV. The largest cosmogenic neutrino flux is given in models with very flat generation spectrum, e.g. $\\propto E^{-2}$. The neutrino energies are naturally high in the models of {\\em superheavy dark matter and topological defects}. Their fluxes can also be higher than those of cosmogenic neutrinos. The largest fluxes are given by {\\em mirror neutrinos}, oscillating into ordinary neutrinos. Their fluxes obey some theoretical upper limit which is very weak, and in practice these fluxes are most efficiently limited now by observations of radio emission from neutrino-induced showers.

  5. MINOS Sterile Neutrino Search

    SciTech Connect (OSTI)

    Koskinen, David Jason; /University Coll. London

    2009-09-01T23:59:59.000Z

    The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline accelerator neutrino experiment designed to measure properties of neutrino oscillation. Using a high intensity muon neutrino beam, produced by the Neutrinos at Main Injector (NuMI) complex at Fermilab, MINOS makes two measurements of neutrino interactions. The first measurement is made using the Near Detector situated at Fermilab and the second is made using the Far Detector located in the Soudan Underground laboratory in northern Minnesota. The primary goal of MINOS is to verify, and measure the properties of, neutrino oscillation between the two detectors using the {nu}{sub {mu}} {yields} V{sub {tau}} transition. A complementary measurement can be made to search for the existence of sterile neutrinos; an oft theorized, but experimentally unvalidated particle. The following thesis will show the results of a sterile neutrino search using MINOS RunI and RunII data totaling {approx}2.5 x 10{sup 20} protons on target. Due to the theoretical nature of sterile neutrinos, complete formalism that covers transition probabilities for the three known active states with the addition of a sterile state is also presented.

  6. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect (OSTI)

    Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan) and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-11-20T23:59:59.000Z

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

  7. Oscillation Effects and Time Variation of the Supernova Neutrino Signal

    E-Print Network [OSTI]

    James P. Kneller; Gail C. McLaughlin; Justin Brockman

    2007-05-25T23:59:59.000Z

    The neutrinos detected from the next Galactic core-collapse supernova will contain valuable information on the internal dynamics of the explosion. One mechanism leading to a temporal evolution of the neutrino signal is the variation of the induced neutrino flavor mixing driven by changes in the density profile. With one and two dimensional hydrodynamical simulations we identify the behavior and properties of prominent features of the explosion. Using these results we demonstrate the time variation of the neutrino crossing probabilities due to changes in the MSW neutrino transformations as the star explodes by using the S-matrix - Monte Carlo - approach to neutrino propagation. After adopting spectra for the neutrinos emitted from the proto-neutron star we calculate for a Galactic supernova the evolution of the positron spectra within a water Cerenkov detector and the ratio of charged current to neutral current event rates for a heavy water - SNO like - detector and find that these detector signals are feasible probes of a number of explosion features.

  8. EA-1943: Long Baseline Neutrino Facility/Deep Underground Neutrino...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    DUNE) at Fermilab, Batavia, Illinois and the Sanford Underground Research Facility, Lead, South Dakota EA-1943: Long Baseline Neutrino FacilityDeep Underground Neutrino...

  9. Acquiring information about neutrino parameters by detecting supernova neutrinos

    SciTech Connect (OSTI)

    Huang, Ming-Yang; Guo, Xin-Heng [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Young, Bing-Lin [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 5001 (United States); Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-08-01T23:59:59.000Z

    We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein 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}{sub 13}, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about {theta}{sub 13} and neutrino masses by detecting supernova neutrinos. We apply these methods to some current neutrino experiments.

  10. New solar opacities, abundances, helioseismology, and neutrino fluxes

    E-Print Network [OSTI]

    John N. Bahcall; Aldo M. Serenelli; Sarbani Basu

    2005-01-19T23:59:59.000Z

    We construct solar models with the newly calculated radiative opacities from the Opacity Project (OP) and recently determined (lower) heavy element abundances. We compare results from the new models with predictions of a series of models that use OPAL radiative opacities, older determinations of the surface heavy element abundances, and refinements of nuclear reaction rates. For all the variations we consider, solar models that are constructed with the newer and lower heavy element abundances advocated by Asplund et al. (2005) disagree by much more than the estimated measuring errors with helioseismological determinations of the depth of the solar convective zone, the surface helium composition, the internal sound speeds, and the density profile. Using the new OP radiative opacities, the ratio of the 8B neutrino flux calculated with the older and larger heavy element abundances (or with the newer and lower heavy element abundances) to the total neutrino flux measured by the Sudbury Neutrino Observatory is 1.09 (0.87) with a 9% experimental uncertainty and a 16% theoretical uncertainty, 1 sigma errors.

  11. Tribimaximal mixing in neutrino mass matrices with texture zeros or vanishing minors

    E-Print Network [OSTI]

    Dev, S; Gautam, Radha Raman

    2010-01-01T23:59:59.000Z

    We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with $\\mu\\tau$ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors in the right-handed Majorana mass matrix having $\\mu\\tau$ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with $\\mu\\tau$ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass $M_{ee}$, the absolute mass scale and the Majorana-type CP violating phases.

  12. Tribimaximal mixing in neutrino mass matrices with texture zeros or vanishing minors

    E-Print Network [OSTI]

    S. Dev; Shivani Gupta; Radha Raman Gautam

    2010-11-25T23:59:59.000Z

    We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with $\\mu\\tau$ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors in the right-handed Majorana mass matrix having $\\mu\\tau$ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with $\\mu\\tau$ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass $M_{ee}$, the absolute mass scale and the Majorana-type CP violating phases.

  13. Running of Low-Energy Neutrino Masses, Mixing Angles and CP Violation

    E-Print Network [OSTI]

    John Ellis; Andi Hektor; Mario Kadastik; Kristjan Kannike; Martti Raidal

    2005-06-13T23:59:59.000Z

    We calculate the running of low-energy neutrino parameters from the bottom up, parameterizing the unknown seesaw parameters in terms of the dominance matrix $R$. We find significant running only if the $R$ matrix is non-trivial and the light-neutrino masses are moderately degenerate. If the light-neutrino masses are very hierarchical, the quark-lepton complementarity relation $\\theta_c + \\theta_{12} = \\pi/4$ is quite stable, but $\\theta_{13,23}$ may run beyond their likely future experimental errors. The running of the oscillation phase $\\delta$ is enhanced by the smallness of $\\theta_{13}$, and jumps in the mixing angles occur in cases where the light-neutrino mass eigenstates cross.

  14. Mind the gap on Icecube: Cosmic neutrino spectrum and muon anomalous magnetic moment in the gauged L_{\\mu} - L_{\\tau} model

    E-Print Network [OSTI]

    Araki, Takeshi; Konishi, Yasufumi; Ota, Toshihiko; Sato, Joe; Shimomura, Takashi

    2014-01-01T23:59:59.000Z

    The energy spectrum of cosmic neutrinos, which was recently reported by the IceCube collaboration, shows a gap between 400 TeV and 1 PeV. An unknown neutrino interaction mediated by a field with a mass of the MeV scale is one of the possible solutions to this gap. We examine if the leptonic gauge interaction L_{\\mu} - L_{\\tau} can simultaneously explain the two phenomena in the lepton sector: the gap in the cosmic neutrino spectrum and the unsettled disagreement in muon anomalous magnetic moment. We illustrate that there remains the regions in the model parameter space, which account for both the problems. Our results also provide a hint for the distance to the source of the high-energy cosmic neutrinos.

  15. Neutrino Decay and Solar Neutrino Seasonal Effect

    E-Print Network [OSTI]

    Picoreti, R; de Holanda, P C; Peres, O L G

    2015-01-01T23:59:59.000Z

    We consider the possibility of solar neutrino decay as a sub-leading effect on their propagation between production and detection. Using current oscillation data, we set a new lower bound to the $\

  16. Physics of Massive Neutrinos

    E-Print Network [OSTI]

    J. W. F. Valle

    2004-10-07T23:59:59.000Z

    I summarize the present status of global analyses of neutrino oscillations, including the most recent KamLAND and K2K data, as well as the latest solar and atmospheric neutrino fluxes. I give the allowed ranges of the three--flavour oscillation parameters from the current worlds' global neutrino data sample, their best fit values and discuss the small parameters DeltaM_solar/DeltaM_atm and sin^2 theta_13, which characterize the strength of CP violation in neutrino oscillations. I briefly discuss neutrinoless double beta decay and the LSND neutrino oscillation hint, as well as the robustness of the neutrino oscillation results in the presence of non-standard physics.

  17. Massive neutrinos and cosmology

    E-Print Network [OSTI]

    Julien Lesgourgues; Sergio Pastor

    2006-05-29T23:59:59.000Z

    The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure. In this review we describe in detail how free-streaming massive neutrinos affect the evolution of cosmological perturbations. We summarize the current bounds on the sum of neutrino masses that can be derived from various combinations of cosmological data, including the most recent analysis by the WMAP team. We also discuss how future cosmological experiments are expected to be sensitive to neutrino masses well into the sub-eV range.

  18. Solar neutrino detection

    E-Print Network [OSTI]

    Lino Miramonti

    2009-01-22T23:59:59.000Z

    More than 40 years ago, neutrinos where conceived as a way to test the validity of the solar models which tell us that stars are powered by nuclear fusion reactions. The first measurement of the neutrino flux, in 1968 in the Homestake mine in South Dakota, detected only one third of the expected value, originating what has been known as the Solar Neutrino Problem. Different experiments were built in order to understand the origin of this discrepancy. Now we know that neutrinos undergo oscillation phenomenon changing their nature traveling from the core of the Sun to our detectors. In the work the 40 year long saga of the neutrino detection is presented; from the first proposals to test the solar models to last real time measurements of the low energy part of the neutrino spectrum.

  19. Spectroscopy of Solar Neutrinos

    E-Print Network [OSTI]

    Michael Wurm; Franz von Feilitzsch; Marianne Goeger-Neff; Tobias Lachenmaier; Timo Lewke; Quirin Meindl; Randoplh Moellenberg; Lothar Oberauer; Walter Potzel; Marc Tippmann; Christoph Traunsteiner; Juergen Winter

    2010-04-06T23:59:59.000Z

    In the last years, liquid-scintillator detectors have opened a new window for the observation of low-energetic astrophysical neutrino sources. In 2007, the solar neutrino experiment Borexino began its data-taking in the Gran Sasso underground laboratory. High energy resolution and excellent radioactive background conditions in the detector allow the first-time spectroscopic measurement of solar neutrinos in the sub-MeV energy regime. The experimental results of the Beryllium-7 neutrino flux measurements as well as the prospects for the detection of solar Boron-8, pep and CNO neutrinos are presented in the context of the currently discussed ambiguities in solar metallicity. In addition, the potential of the future SNO+ and LENA experiments for high-precision solar neutrino spectroscopy will be outlined.

  20. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Petr Vogel; Liangjian Wen; Chao Zhang

    2015-03-03T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  1. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Petr Vogel; Liangjian Wen; Chao Zhang

    2015-04-27T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  2. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Vogel, Petr; Zhang, Chao

    2015-01-01T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  3. Neutrinos from Gamma Ray Bursts

    E-Print Network [OSTI]

    F. Halzen; G. Jaczko

    1996-02-07T23:59:59.000Z

    We show that the detection of neutrinos from a typical gamma ray burst requires a kilometer-scale detector. We argue that large bursts should be visible with the neutrino telescopes under construction. We emphasize the 3 techniques by which neutrino telescopes can perform this search: by triggering on i) bursts of muons from muon neutrinos, ii) muons from air cascades initiated by high energy gamma rays and iii) showers made by relatively low energy ($\\simeq 100\\,\\mev$) electron neutrinos. Timing of neutrino-photon coincidences may yield a measurement of the neutrino mass to order $10^{-5}$~eV, an interesting range in light of the solar neutrino anomaly.

  4. Neutrino oscillation studies with reactors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vogel, P. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Kellog Radiation Lab.; Wen, L.J. [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Zhang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-04-27T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle ?13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  5. Neutrinos: Nature's Ghosts?

    SciTech Connect (OSTI)

    Lincoln, Don

    2013-06-18T23:59:59.000Z

    Dr. Don Lincoln introduces one of the most fascinating inhabitants of the subatomic realm: the neutrino. Neutrinos are ghosts of the microworld, almost not interacting at all. In this video, he describes some of their properties and how they were discovered. Studies of neutrinos are expected to be performed at many laboratories across the world and to form one of the cornerstones of the Fermilab research program for the next decade or more.

  6. Neutrinos: Nature's Ghosts?

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-12T23:59:59.000Z

    Dr. Don Lincoln introduces one of the most fascinating inhabitants of the subatomic realm: the neutrino. Neutrinos are ghosts of the microworld, almost not interacting at all. In this video, he describes some of their properties and how they were discovered. Studies of neutrinos are expected to be performed at many laboratories across the world and to form one of the cornerstones of the Fermilab research program for the next decade or more.

  7. Kinetics of Oscillating Neutrinos

    E-Print Network [OSTI]

    P. Strack

    2005-05-12T23:59:59.000Z

    In the context of core-collapse supernovae, Strack and Burrows (Phys. Rev. D 71, 093004 (2005)) have recently developed an extension of the classical Boltzmann kinetic formalism that retains all the standard neutrino oscillation phenomenology, including resonant flavor conversion (the MSW effect), neutrino self-interactions, and the interplay between neutrino-matter coupling and flavor oscillations. In this thesis, I extend the Strack & Burrows formalism to incorporate general relativity, spin degrees of freedom, and a possible neutrino magnetic-moment/magnetic-field interaction.

  8. Neutrino-nucleus interactions

    SciTech Connect (OSTI)

    Gallagher, H.; /Tufts U.; Garvey, G.; /Los Alamos; Zeller, G.P.; /Fermilab

    2011-01-01T23:59:59.000Z

    The study of neutrino oscillations has necessitated a new generation of neutrino experiments that are exploring neutrino-nuclear scattering processes. We focus in particular on charged-current quasi-elastic scattering, a particularly important channel that has been extensively investigated both in the bubble-chamber era and by current experiments. Recent results have led to theoretical reexamination of this process. We review the standard picture of quasi-elastic scattering as developed in electron scattering, review and discuss experimental results, and discuss additional nuclear effects such as exchange currents and short-range correlations that may play a significant role in neutrino-nucleus scattering.

  9. Atmospheric Neutrino Fluxes

    E-Print Network [OSTI]

    Thomas K. Gaisser

    2005-02-18T23:59:59.000Z

    Starting with an historical review, I summarize the status of calculations of the flux of atmospheric neutrinos and how they compare to measurements.

  10. Composite Dirac Neutrinos

    E-Print Network [OSTI]

    Yuval Grossman; Dean J Robinson

    2011-01-25T23:59:59.000Z

    We present a mechanism that naturally produces light Dirac neutrinos. The basic idea is that the right-handed neutrinos are composite. Any realistic composite model must involve `hidden flavor' chiral symmetries. In general some of these symmetries may survive confinement, and in particular, one of them manifests itself at low energy as an exact $B-L$ symmetry. Dirac neutrinos are therefore produced. The neutrinos are naturally light due to compositeness. In general, sterile states are present in the model, some of them can naturally be warm dark matter candidates.

  11. Search for Pair Production of Heavy Top-Like Quarks Decaying to a High-p[subscript T]W Boson and a b Quark in the Lepton Plus Jets Final State at ?s = 7 TeV with the ATLAS Detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for production of a heavy up-type quark (t[superscript ?]) together with its antiparticle, assuming a significant branching ratio for subsequent decay into a W boson and a b quark. The search is ...

  12. Search for Lepton-Flavor and Lepton-Number Violation in the Decay tau to lhh'

    SciTech Connect (OSTI)

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San

    2005-06-29T23:59:59.000Z

    A search for lepton-flavor and lepton-number violation in the decay of the tau lepton into one charged lepton and two charged hadrons is performed using 221.4 fb{sup -1} of data collected at an e{sup +}e{sup -} center-of-mass energy of 10.58 GeV with the BABAR detector at the PEP-II storage ring. In all 14 decay modes considered, the observed data are compatible with background expectations, and upper limits are set in the range {Beta}({tau} {yields} {ell}hh') < (0.7-4.8) x 10{sup -7} at 90% confidence level.

  13. Charged-Lepton-Flavour Violation in the Light of the Super-Kamiokande Data

    E-Print Network [OSTI]

    John Ellis; M. E. Gomez; G. K. Leontaris; S. Lola; D. V. Nanopoulos

    1999-12-18T23:59:59.000Z

    Motivated by the data from Super-Kamiokande and elsewhere indicating oscillations of atmospheric and solar neutrinos, we study charged-lepton-flavour violation, in particular the radiative decays mu -> e gamma and tau -> mu gamma, but also commenting on mu -> 3e and tau -> 3 mu/e decays, as well as mu - e conversion on nuclei. We first show how the renormalization group may be used to calculate flavour-violating soft supersymmetry-breaking masses for charged sleptons and sneutrinos in models with universal input parameters. Subsequently, we classify possible patterns of lepton-flavour violation in the context of phenomenological neutrino mass textures that accommodate the Super-Kamiokande data, giving examples based on Abelian flavour symmetries. Then we calculate in these examples rates for mu -> e gamma and tau ->mu gamma, which may be close to the present experimental upper limits, and show how they may distinguish between the different generic mixing patterns. The rates are promisingly large when the soft supersymmetry-breaking mass parameters are chosen to be consistent with the cosmological relic-density constraints. In addition, we discuss mu -> e conversion on Titanium, which may also be accessible to future experiments.

  14. 0+ -> 2+ neutrinoless double beta decay triggered directly by the Majorana neutrino mass

    E-Print Network [OSTI]

    T. Tomoda

    1999-09-12T23:59:59.000Z

    We treat 0+ -> 2+ neutrinoless double beta decays taking into account recoil corrections to the nuclear currents. The decay probability can be written as a quadratic form of the effective coupling constants of the right-handed leptonic currents and the effective neutrino mass. We calculate the nuclear matrix elements for the 0+ -> 2+ neutrinoless double beta decays of 76Ge and 100Mo, and demonstrate that the relative sensitivities of 0+ -> 2+ decays to the neutrino mass and the right-handed currents are comparable to those of 0+ -> 0+ decays.

  15. New Neutrinos Algal Biofuels

    E-Print Network [OSTI]

    ) HEAVY HITTER SOLAR SYSTEM SURPRISE REACTION TO FUKUSHIMA GREENHOUSE GANG SOLVAY CENTENNIAL 1663 los

  16. Neutrino and anti-neutrino transport in accretion disks

    E-Print Network [OSTI]

    Zhen Pan; Ye-Fei Yuan

    2012-02-09T23:59:59.000Z

    We numerically solve the one dimensional Boltzmann equation of the neutrino and anti-neutrino transport in accretion disks and obtain the fully energy dependent and direction dependent neutrino and anti-neutrino emitting spectra, under condition that the distribution of the mass density,temperature and chemical components are given. Then, we apply the resulting neutrino and anti-neutrino emitting spectra to calculate the corresponding annihilation rate of neutrino pairs above the neutrino dominated accretion disk and find that the released energy resulting from the annihilation of neutrino pairs can not provide sufficient energy for the most energetic short gamma ray bursts whose isotropic luminosity can be as high as $10^{52}$ ergs/s unless the high temperature zone where the temperature is beyond 10 MeV can stretch over 200 km in the disk. We also compare the resulting luminosity of neutrinos and anti-neutrinos with the results from the two commonly used approximate treatment of the neutrino and anti-neutrino luminosity: the Fermi-Dirac black body limit and a simplified model of neutrino transport, i.e., the gray body model, and find that both of them overestimate the neutrino/anti-neutrino luminosity and their annihilation rate greatly. Additionally, as did in Sawyer (2003), we also check the validity of the two stream approximation, and find that it is a good approximation to high accuracy.

  17. Textures with two traceless submatrices of the neutrino mass matrix

    E-Print Network [OSTI]

    H. A. Alhendi; E. I. Lashin; A. A. Mudlej

    2008-02-27T23:59:59.000Z

    We propose a new texture for the light neutrino mass matrix. The proposal is based upon imposing zero-trace condition on the two by two sub-matrices of the complex symmetric Majorana mass matrix in the flavor basis where the charged lepton mass matrix is diagonal. Restricting the mass matrix to have two traceless sub-matrices may be found sufficient to describe the current data. Eight out of fifteen independent possible cases are found to be compatible with current data. Numerical and some approximate analytical results are presented.

  18. Cosmological Neutrino Mass Detection: The Best Probe of Neutrino Lifetime

    SciTech Connect (OSTI)

    Serpico, Pasquale D. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States)

    2007-04-27T23:59:59.000Z

    Future cosmological data may be sensitive to the effects of a finite sum of neutrino masses even as small as {approx}0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a cosmological detection of neutrino mass at that level would improve by many orders of magnitude the existing limits on neutrino lifetime, and as a consequence, on neutrino secret interactions with (quasi)massless particles as in Majoron models. On the other hand, neutrino decay may provide a way out to explain a discrepancy < or approx. 0.1 eV between cosmic neutrino bounds and lab data.

  19. Cosmological neutrino mass detection: The Best probe of neutrino lifetime

    SciTech Connect (OSTI)

    Serpico, Pasquale D.; /Fermilab

    2007-01-01T23:59:59.000Z

    Future cosmological data may be sensitive to the effects of a finite sum of neutrino masses even as small as {approx}0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a cosmological detection of neutrino mass at that level would improve by many orders of magnitude the existing limits on neutrino lifetime, and as a consequence on neutrino secret interactions with (quasi-)massless particles as in majoron models. On the other hand, neutrino decay may provide a way-out to explain a discrepancy {approx}< 0.1 eV between cosmic neutrino bounds and Lab data.

  20. Neutrino oscillations: another physics?

    E-Print Network [OSTI]

    S. N. Vergeles

    2014-07-21T23:59:59.000Z

    It is shown that the neutrino oscillations phenomenon may be attributed to the Wilson fermion doubling phenomenon. The Wilson fermion doubling exists only on the lattices, both periodic and non-periodic (simplicial complexes). Just the last case plays a key role here. Thereby, the neutrino oscillations may show for the existence of a space-time granularity.

  1. Neutrino Oscillations and Cosmology

    E-Print Network [OSTI]

    A. D. Dolgov

    2000-04-04T23:59:59.000Z

    Phenomenology of neutrino oscillations in vacuum and in cosmological plasma is considered. Neutrino oscillations in vacuum are usually described in plane wave approximation. In this formalism there is an ambiguity if one should assume $\\delta p =0$ and correspondingly $\\delta E\

  2. Neutrino oscillations: another physics?

    E-Print Network [OSTI]

    Vergeles, S N

    2014-01-01T23:59:59.000Z

    It is shown that the neutrino oscillations phenomenon may be attributed to the Wilson fermion doubling phenomenon. The Wilson fermion doubling exists only on the lattices, both periodic and non-periodic (simplicial complexes). Just the last case plays a key role here. Thereby, the neutrino oscillations may show for the existence of a space-time granularity.

  3. The Sudbury Neutrino Observatory

    SciTech Connect (OSTI)

    Hime, A.

    1996-09-01T23:59:59.000Z

    A report is given on the status of the Sudbury Neutrino Observatory, presently under construction in the Creighton nickel mine near Sudbury, Ontario in Canada. Focus is upon the technical factors involving a measurement of the charged-current and neutral-current interactions of solar neutrinos on deuterium.

  4. Reactor Monitoring with Neutrinos

    E-Print Network [OSTI]

    M. Cribier

    2007-04-06T23:59:59.000Z

    The fundamental knowledge on neutrinos acquired in the recent years open the possibility of applied neutrino physics. Among it the automatic and non intrusive monitoring of nuclear reactor by its antineutrino signal could be very valuable to IAEA in charge of the control of nuclear power plants. Several efforts worldwide have already started.

  5. Verifiable radiative seesaw mechanism of neutrino mass and dark matter

    SciTech Connect (OSTI)

    Ma, Ernest [Physics Department, University of California, Riverside, California 92521 (United States)

    2006-04-01T23:59:59.000Z

    Neutrino oscillations have established that neutrinos {nu}{sub i} have very small masses. Theoretically, they are believed to arise through the famous seesaw mechanism from their very heavy and unobservable Dirac mass partners N{sub i}. It is proposed here in a new minimal extension of the standard model with a second scalar doublet ({eta}{sup +}, {eta}{sup 0}) that the seesaw mechanism is actually radiative, and that N{sub i} and ({eta}{sup +}, {eta}{sup 0}) are experimentally observable at the forthcoming Large Hadron Collider, with the bonus that the lightest of them is also an excellent candidate for the dark matter of the Universe.

  6. Pattern of neutrino mixing in grand unified theories

    SciTech Connect (OSTI)

    Milton, K.; Tanaka, K.

    1981-01-01T23:59:59.000Z

    It was found previously in SO(10) grand unified theories that if the neutrinos have a Dirac mass and a right-handed Majorana mass (approx. 10/sup 15/GeV) but no left-handed Majorana mass, there is small ..nu../sub e/ mixing but ..nu../sub ..mu../ - ..nu../sub tau/ mixing can be substantial. This problem is reexamined on the basis of a formalism that assumes that the up, down, lepton, and neutrino mass matrices arise from a single complex 10 and a single 126 Higgs boson. This formalism determines the Majorana mass matrix in terms of quark mass matrices. Adopting three different sets of quark mass matrices that produce acceptable fermion mass ratios and Cabbibo mixing produces results consistent with the above; however, in the optimum case, ..nu../sub e/ - ..nu../sub ..mu../ mixing can be of the order of the Cabbibo angle.

  7. {mu}-{tau} symmetry, sterile right-handed neutrinos, and leptogenesis

    SciTech Connect (OSTI)

    Riazuddin [National Centre for Physics, Quaid-i-Azam University, Islamabad (Pakistan)

    2008-01-01T23:59:59.000Z

    Leptogenesis is studied in a seesaw model with {mu}-{tau} symmetry for SU{sub L}(2)-singlet right-handed neutrinos. It is shown that lepton asymmetry is not zero and is given by the square of the solar neutrino mass difference and can be of the right order of magnitude. Further it involves the same Majorana phase which appears in the neutrinoless double {beta}-decay. In this framework one of the right-handed seesaw partners of light neutrinos can be made massless. This can be identified with a sterile neutrino, once it acquires a tiny mass ({approx_equal}1 eV) when {mu}-{tau} symmetry is broken in the right-handed neutrino sector. The above mentioned sterile neutrino together with another one can be identified to explain the MiniBooNE and LSND results. The light 5x5 neutrino mass matrix is completely fixed if CP is conserved and so is the effective mass for neutrinoless double {beta}-decay.

  8. Impact of Neutrino Oscillation Measurements on Theory

    E-Print Network [OSTI]

    Murayama, Hitoshi

    2009-01-01T23:59:59.000Z

    was an amazing year in neutrino physics. Before March, thetheorists have a very good track record in neutrino physics.results from neutrino oscillation physics had surprised

  9. Mass Hierarchy via Mossbauer and Reactor Neutrinos

    E-Print Network [OSTI]

    Stephen Parke; Hisakazu Minakata; Hiroshi Nunokawa; Renata Zukanovich Funchal

    2008-12-10T23:59:59.000Z

    We show how one could determine the neutrino mass hierarchy with Mossbauer neutrinos and also revisit the question of whether the hierarchy can be determined with reactor neutrinos.

  10. Mass Hierarchy via Mossbauer and Reactor Neutrinos

    E-Print Network [OSTI]

    Parke, Stephen; Nunokawa, Hiroshi; Funchal, Renata Zukanovich

    2008-01-01T23:59:59.000Z

    We show how one could determine the neutrino mass hierarchy with Mossbauer neutrinos and also revisit the question of whether the hierarchy can be determined with reactor neutrinos.

  11. Neutrino oscillations and dark matter

    E-Print Network [OSTI]

    K. Zuber

    1996-12-17T23:59:59.000Z

    The significance of light massive neutrinos as hot dark matter is outlined. The power of neutrino oscillation experiments with respect to detect such neutrinos in the eV-region is discussed. Present hints for neutrino oscillations in solar, atmospheric and LSND data are reviewed as well as future experiments and their potential.

  12. The ANTARES Neutrino Telescope

    E-Print Network [OSTI]

    Perrina, Chiara

    2015-01-01T23:59:59.000Z

    At about 40 km off the coast of Toulon (France), anchored at 2475 m deep in the Mediterranean Sea, there is ANTARES: the first undersea neutrino telescope and the only one currently operating. The detector consists of 885 photomultiplier tubes arranged into 12 strings of 450-metres high, with the aim to detect the Cherenkov light induced by the charged superluminal interaction products of neutrinos. Its main scientific target is the search for high-energy (TeV and beyond) neutrinos from cosmic accelerators, as predicted by hadronic interaction models, and the measurement of the cosmic neutrino diffuse flux, focusing in particular on events coming from below the horizon (up-going events) in order to significantly reduce the atmospheric muons background. Thanks to the development of a strategy for the identification of neutrinos coming from above the horizon (down-going events) the field of view of the telescope will be extended.

  13. Determining Reactor Neutrino Flux

    E-Print Network [OSTI]

    Jun Cao

    2012-03-08T23:59:59.000Z

    Flux is an important source of uncertainties for a reactor neutrino experiment. It is determined from thermal power measurements, reactor core simulation, and knowledge of neutrino spectra of fuel isotopes. Past reactor neutrino experiments have determined the flux to (2-3)% precision. Precision measurements of mixing angle $\\theta_{13}$ by reactor neutrino experiments in the coming years will use near-far detector configurations. Most uncertainties from reactor will be canceled out. Understanding of the correlation of uncertainties is required for $\\theta_{13}$ experiments. Precise determination of reactor neutrino flux will also improve the sensitivity of the non-proliferation monitoring and future reactor experiments. We will discuss the flux calculation and recent progresses.

  14. The Final Results from the Sudbury Neutrino Observatory

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    The Sudbury Neutrino Observatory (SNO) was a water Cherenkov detector dedicated to investigate elementary particles called neutrinos. It successfully took data between 1999 and 2006. The detector was unique in its use of heavy water as a detection medium, permitting it to make a solar model-independent test of solar neutrino mixing. In fact, SNO conclusively showed that solar neutrinos oscillate on their way from the core of the Sun to the Earth. This groundbreaking observation was made during three independent phases of the experiment. Even if data taking ended, SNO is still in a mode of precise determination of the solar neutrino oscillation parameters because all along SNO had developed several methods to tell charged-current events apart from neutral-current events. This ability is crucial for the final and ultimate data analysis of all the phases. The physics reach of a combined three-phase solar analysis will be reviewed together with results and subtleties about solar neutrino physics.

  15. Neutrino observations from the Sudbury Neutrino Observatory

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    Energy of Canada Limited (AECL), Agra-Monenco, Canatom,The heavy water was loaned by AECL with the cooperation of

  16. Neutrino-neutrino interactions in a supernova and their effect on neutrino flavor conversions

    SciTech Connect (OSTI)

    Dighe, Amol [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2011-11-23T23:59:59.000Z

    The neutrino-neutrino interactions inside a supernova core give rise to nonlinear collective effects that significantly influence the neutrino flavor conversions inside the star. I shall describe these interactions, the new oscillation phenomena they generate, and their effect on the neutrino fluxes arriving at the earth.

  17. MASSIVE NEUTRINOS IN A GROUNDS-UP APPROACH.

    SciTech Connect (OSTI)

    BAR-SHALOM, S.; ATWOOD, D.; SONI, A.

    2005-07-21T23:59:59.000Z

    We examine neutrino oscillations in a two Higgs doublet model (2HDM) in which the second doublet couples only to the third generation right-handed up-fermions, i.e., to t{sub R} and N{sub 3} which is the heaviest right-handed Majorana neutrino. The inherently large tan {beta} of this model can naturally account for the large top-quark mass and, based on a quark-lepton similarity ansatz, when embedded into a seesaw mechanism it can also account for the observed neutrino masses and mixing angles giving a very small {theta}{sub 13}: -0.96{sup 0} {approx}< {theta}{sub 13} {approx}< 1.36{sup 0} at 99% CL, and a very restrictive prediction for the atmospheric mixing angle: 42.9{sup 0} {approx}< {theta}{sub atm} {approx}< 45.2{sup 0} at 99% CL. The large value of tan {beta} also sets the mass scale of the heaviest right-handed Majorana neutrino N{sub 3} and triggers successful leptogenesis.

  18. Running of Radiative Neutrino Masses: The Scotogenic Model

    E-Print Network [OSTI]

    Romain Bouchand; Alexander Merle

    2012-04-30T23:59:59.000Z

    We study the renormalization group equations of Ma's scotogenic model, which generates an active neutrino mass at 1-loop level. In addition to other benefits, the main advantage of the mechanism exploited in this model is to lead to a natural loop-suppression of the neutrino mass, and therefore to an explanation for its smallness. However, since the structure of the neutrino mass matrix is altered compared to the ordinary type I seesaw case, the corresponding running is altered as well. We have derived the full set of renormalization group equations for the scotogenic model which, to our knowledge, had not been presented previously in the literature. This set of equations reflects some interesting structural properties of the model, and it is an illustrative example for how the running of neutrino parameters in radiative models is modified compared to models with tree-level mass generation. We also study a simplified numerical example to illustrate some general tendencies of the running. Interestingly, the structure of the RGEs can be exploited such that a bimaximal leptonic mixing pattern at the high-energy scale is translated into a valid mixing pattern at low energies, featuring a large value of \\theta_{13}. This suggests very interesting connections to flavour symmetries.

  19. Heavy quark physics from SLD

    SciTech Connect (OSTI)

    Messner, R. [Stanford Univ., CA (United States)

    1997-01-01T23:59:59.000Z

    This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.

  20. Running of Neutrino Oscillation Parameters in Matter with Flavor-Diagonal Non-Standard Interactions of the Neutrino

    E-Print Network [OSTI]

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

    2015-06-28T23:59:59.000Z

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

  1. Absolute neutrino mass measurements

    SciTech Connect (OSTI)

    Wolf, Joachim [Karlsruhe Institute of Technology (KIT), IEKP, Postfach 3640, 76021 Karlsruhe (Germany)

    2011-10-06T23:59:59.000Z

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.

  2. What conditions must be placed on the neutrino mixing matrix in order to have the same amount of e in 3 as in ?

    E-Print Network [OSTI]

    Golwala, Sunil

    matrices, this probability works out to be: P(µ e) = sin2 23 sin2 213 sin2(1.27m2 31L/E). [Next Slide] 3 to lepton number for Majorana neutrinos? "...L mixes and ¯. Thus, a Majorana mass term does not conserve L

  3. Neutrinos: Nature's Identity Thieves?

    SciTech Connect (OSTI)

    Lincoln, Don

    2013-07-11T23:59:59.000Z

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

  4. Neutrinos: Nature's Identity Thieves?

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-07T23:59:59.000Z

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

  5. Neutrinos: Nature's Identity Thieves?

    ScienceCinema (OSTI)

    Dr. Don Lincoln

    2013-07-22T23:59:59.000Z

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

  6. Reactor Neutrino Experiments

    E-Print Network [OSTI]

    Jun Cao

    2007-12-06T23:59:59.000Z

    Precisely measuring $\\theta_{13}$ is one of the highest priority in neutrino oscillation study. Reactor experiments can cleanly determine $\\theta_{13}$. Past reactor neutrino experiments are reviewed and status of next precision $\\theta_{13}$ experiments are presented. Daya Bay is designed to measure $\\sin^22\\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent improvements in neutrino moment measurement are also briefed.

  7. A search for muon neutrino and antineutrino disappearance in the Booster Neutrino Beam

    SciTech Connect (OSTI)

    Mahn, Kendall Brianna McConnel; /Columbia U.

    2009-04-01T23:59:59.000Z

    This dissertation presents a search for {mu}{sub {nu}} and {bar {mu}{sub {nu}}} disappearance with the MiniBooNE experiment in the {Delta}m{sup 2} region of a few eV{sup 2}. Disappearance measurements in this oscillation region constrain sterile neutrino models and CPT violation in the lepton sector. Fits to the shape of the {mu}{sub {nu}} and {bar {mu}{sub {nu}}} energy spectra reveal no evidence for disappearance in either mode. This is the first test of {bar {mu}{sub {nu}}} disappearance between {Delta}m{sup 2} = 0:1 -- 10 eV2. In addition, prospects for performing a joint analysis using the SciBooNE detector in conjunction with MiniBooNE are discussed.

  8. Majorana neutrino superfluidity and stability of neutrino dark energy

    SciTech Connect (OSTI)

    Bhatt, Jitesh R.; Sarkar, Utpal [Physical Research Laboratory, Ahmedabad 380009 (India)

    2009-08-15T23:59:59.000Z

    We demonstrate that Majorana neutrinos can form Cooper pairs due to long-range attractive forces and show BCS superfluidity in a class of mass varying neutrino dark energy models. We describe the condensates for Majorana neutrinos and estimate the value of the gap, critical temperature, and Pippard coherence length for a simple neutrino dark energy model. In the strong coupling regime bosonic degree of freedom can become important, and Bose-Einstein condensate may govern the dynamics for the mass varying neutrino models. Formation of the condensates can significantly alter the instability scenario in the mass varying neutrino models.

  9. Neutrino Masses in Astroparticle Physics

    E-Print Network [OSTI]

    G. G. Raffelt

    2002-08-08T23:59:59.000Z

    The case for small neutrino mass differences from atmospheric and solar neutrino oscillation experiments has become compelling, but leaves the overall neutrino mass scale m_nu undetermined. The most restrictive limit of m_nu neutrinos. If solar neutrino oscillations indeed correspond to the favored large mixing angle MSW solution, then big-bang nucleosynthesis gives us a restrictive limit on all neutrino chemical potentials, removing the previous uncertainty of n_nu. Therefore, a possible future measurement of m_nu will directly establish the cosmic neutrino mass fraction Omega_nu. Cosmological neutrinos with sub-eV masses can play an interesting role for producing the highest-energy cosmic rays (Z-burst scenario). Sub-eV masses also relate naturally to leptogenesis scenarios of the cosmic baryon asymmetry. Unfortunately, the time-of-flight dispersion of a galactic or local-group supernova neutrino burst is not sensitive in the sub-eV range.

  10. Berry Phase in Neutrino Oscillations

    E-Print Network [OSTI]

    Xiao-Gang He; Xue-Qian Li; Bruce H. J. McKellar; Yue Zhang

    2005-05-18T23:59:59.000Z

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

  11. DELAYED ONSET OF HIGH-ENERGY EMISSIONS IN LEPTONIC AND HADRONIC MODELS OF GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Asano, Katsuaki [Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Meszaros, Peter, E-mail: asano@phys.titech.ac.jp, E-mail: nnp@astro.psu.edu [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2012-10-01T23:59:59.000Z

    The temporal-spectral evolution of the prompt emission of gamma-ray bursts is simulated numerically for both leptonic and hadronic models. For weak enough magnetic fields, leptonic models can reproduce the few seconds delay of the onset of GeV photon emission observed by Fermi-LAT, due to the slow growth of the target photon field for inverse Compton scattering. For stronger magnetic fields, the GeV delay can be explained with hadronic models, due to the long acceleration timescale of protons and the continuous photopion production after the end of the particle injection. While the FWHMs of the MeV and GeV light curves are almost the same in one-zone leptonic models, the FWHMs of the 1-30 GeV light curves in hadronic models are significantly wider than those of the 0.1-1 MeV light curves. The amount of the GeV delay depends on the importance of the Klein-Nishina effect in both the leptonic and hadronic models. In our examples of hadronic models the energies of the escaped neutrons are comparable to the gamma-ray energy, although their contribution to the ultra high-energy cosmic rays is still subdominant. The resulting neutrino spectra are hard enough to avoid the flux limit constraint from IceCube. The delay of the neutrino emission onset is up to several times longer than the corresponding delay of the GeV photon emission onset. The quantitative differences in the light curves for various models may be further tested with future atmospheric Cerenkov telescopes whose effective area is larger than that of Fermi-LAT, such as CTA.

  12. Radiative inverse seesaw neutrino mass and dark matter

    SciTech Connect (OSTI)

    Guo Gang [INPAC, Department of Physics and Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai Jiao Tong University, Shanghai (China); He Xiaogang [INPAC, Department of Physics and Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai Jiao Tong University, Shanghai (China) and Department of Physics, National Tsing Hua University, and NCTS, Hsinchu, Taiwan (China); Li Guannan [INPAC, Department of Physics and Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai Jiao Tong University, Shanghai, Taiwan (China)

    2013-05-23T23:59:59.000Z

    Seesaw mechanism provides a natural explanation of light neutrino masses through suppression of heavy seesaw scale. In inverse seesaw models the seesaw scale can be much lower than that in the usual seesaw models. If terms inducing seesaw masses are further induced by loop corrections, the seesaw scale can be lowered to be in the range probed by experiments at the LHC without fine tuning. This talk, presented by X-G He, discuss models constructed in a recent preprint by us (arxiv:201207.6308) in which neutrino masses are generated at two loop level through inverse seesaw mechanism. These models also naturally have dark matter candidates. Although the recent data from Xenon100 put stringent constraint on the models, they can be consistent with data on neutrino masses, mixing, dark matter relic density and direct detection.

  13. Radiative Corrections to Light Neutrino Masses in Low Scale Type I Seesaw Scenarios and Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    Lopez-Pavon, J; Petcov, S T

    2015-01-01T23:59:59.000Z

    We perform a detailed analysis of the one-loop corrections to the light neutrino mass matrix within low scale type I seesaw extensions of the Standard Model and their implications in experimental searches for neutrinoless double beta decay. We show that a sizable contribution to the effective Majorana neutrino mass from the exchange of heavy Majorana neutrinos is always possible, provided one requires a fine-tuned cancellation between the tree-level and one-loop contribution to the light neutrino masses. We quantify the level of fine-tuning as a function of the seesaw parameters and introduce a generalisation of the Casas-Ibarra parametrization of the neutrino Yukawa matrix, which easily allows to include the one-loop corrections to the light neutrino masses.

  14. Optical calibration hardware for the Sudbury Neutrino Observatory

    E-Print Network [OSTI]

    B. A. Moffat; R. J. Ford; F. A. Duncan; K. Graham; A. L. Hallin; C. A. W. Hearns; J. Maneira; P. Skensved; D. R. Grant

    2005-07-19T23:59:59.000Z

    The optical properties of the Sudbury Neutrino Observatory (SNO) heavy water Cherenkov neutrino detector are measured in situ using a light diffusing sphere ("laserball"). This diffuser is connected to a pulsed nitrogen/dye laser via specially developed underwater optical fibre umbilical cables. The umbilical cables are designed to have a small bending radius, and can be easily adapted for a variety of calibration sources in SNO. The laserball is remotely manipulated to many positions in the D2O and H2O volumes, where data at six different wavelengths are acquired. These data are analysed to determine the absorption and scattering of light in the heavy water and light water, and the angular dependence of the response of the detector's photomultiplier tubes. This paper gives details of the physical properties, construction, and optical characteristics of the laserball and its associated hardware.

  15. Neutrino astrophysics : recent advances and open issues

    E-Print Network [OSTI]

    Volpe, Cristina

    2015-01-01T23:59:59.000Z

    We highlight recent advances in neutrino astrophysics, the open issues and the interplay with neutrino properties. We emphasize the important progress in our understanding of neutrino flavor conversion in media. We discuss the case of solar neutrinos, of core-collapse supernova neutrinos and of SN1987A, and of the recently discovered ultra-high energy neutrinos whose origin is to be determined.

  16. Limits on tau lepton flavor violating decays in three charged leptons

    SciTech Connect (OSTI)

    Cervelli, Alberto

    2010-04-29T23:59:59.000Z

    A search for the neutrinoless, lepton-flavor violating decay of the {tau} lepton into three charged leptons has been performed using an integrated luminosity of 468 fb{sup -1} collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8-3.3) x 10{sup -8} at 90% confidence level.

  17. Neutrino oscillations refitted

    E-Print Network [OSTI]

    Forero, D V; Valle, J W F

    2014-01-01T23:59:59.000Z

    Here we update our previous global fit of neutrino oscillations by including the recent results which have appeared since the Neutrino-2012 conference. These include the measurements of reactor anti-neutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle $\\theta_{23}$ is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with emphasis on the increasing sensitivity to the CP phase, thanks to the interplay between accelerator and reactor data.

  18. WMAPping out Neutrino Masses

    E-Print Network [OSTI]

    Aaron Pierce; Hitoshi Murayama

    2003-10-28T23:59:59.000Z

    Recent data from from the Wilkinson Microwave Anisotropy Probe (WMAP) place important bounds on the neutrino sector. The precise determination of the baryon number in the universe puts a strong constraint on the number of relativistic species during Big-Bang Nucleosynthesis. WMAP data, when combined with the 2dF Galaxy Redshift Survey (2dFGRS), also directly constrain the absolute mass scale of neutrinos. These results impinge upon a neutrino oscillation interpretation of the result from the Liquid Scintillator Neutrino Detector (LSND). We also note that the Heidelberg--Moscow evidence for neutrinoless double beta decay is only consistent with the WMAP+2dFGRS data for the largest values of the nuclear matrix element.

  19. Two Questions About Neutrinos

    SciTech Connect (OSTI)

    Kayser, Boris

    2010-12-01T23:59:59.000Z

    We explain why the see-saw picture and leptogenesis make it particularly interesting to find out whether neutrinos are their own antiparticles, and whether their oscillations violate CP.

  20. Pulsar kicks from neutrino oscillations

    E-Print Network [OSTI]

    Alexander Kusenko

    2004-09-27T23:59:59.000Z

    Neutrino oscillations in a core-collapse supernova may be responsible for the observed rapid motions of pulsars. Given the present bounds on the neutrino masses, the pulsar kicks require a sterile neutrino with mass 2-20 keV and a small mixing with active neutrinos. The same particle can be the cosmological dark matter. Its existence can be confirmed the by the X-ray telescopes if they detect a 1-10 keV photon line from the decays of the relic sterile neutrinos. In addition, one may be able to detect gravity waves from a pulsar being accelerated by neutrinos in the event of a nearby supernova.

  1. Radiochemical solar neutrino experiments

    E-Print Network [OSTI]

    V. N. Gavrin; B. T. Cleveland

    2007-03-06T23:59:59.000Z

    Radiochemical experiments have been crucial to solar neutrino research. Even today, they provide the only direct measurement of the rate of the proton-proton fusion reaction, p + p --> d + e^+ + nu_e, which generates most of the Sun's energy. We first give a little history of radiochemical solar neutrino experiments with emphasis on the gallium experiment SAGE -- the only currently operating detector of this type. The combined result of all data from the Ga experiments is a capture rate of 67.6 +/- 3.7 SNU. For comparison to theory, we use the calculated flux at the Sun from a standard solar model, take into account neutrino propagation from the Sun to the Earth and the results of neutrino source experiments with Ga, and obtain 67.3 ^{+3.9}_{-3.5} SNU. Using the data from all solar neutrino experiments we calculate an electron neutrino pp flux at the earth of (3.41 ^{+0.76}_{-0.77}) x 10^{10}/(cm^2-s), which agrees well with the prediction from a detailed solar model of (3.30 ^{+0.13} _{-0.14}) x 10^{10}/(cm^2-s). Four tests of the Ga experiments have been carried out with very intense reactor-produced neutrino sources and the ratio of observed to calculated rates is 0.88 +/- 0.05. One explanation for this unexpectedly low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71Ge has been overestimated. We end with consideration of possible time variation in the Ga experiments and an enumeration of other possible radiochemical experiments that might have been.

  2. Neutrino Interactions with Nuclei

    SciTech Connect (OSTI)

    Leitner, T.; Buss, O.; Mosel, U. [Institut fuer Theoretische Physik, Universitaet Giessen (Germany); Alvarez-Ruso, L. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC (Spain)

    2007-12-21T23:59:59.000Z

    We investigate neutrino-nucleus collisions at intermediate energies incorporating quasielastic scattering and the excitation of 13 resonances as elementary processes, taking into account medium effects such as Fermi motion, Pauli blocking, mean-field potentials and in-medium spectral functions. A coupled-channel treatment of final state interactions is achieved with the GiBUU transport model. Results for inclusive reactions, neutrino- and electron-induced, as well as for pion production and nucleon knockout are presented.

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

    SciTech Connect (OSTI)

    Kishimoto, T.; Nomachi, M. [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka Japan (Japan); Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka Ibaraki Osaka Japan (Japan); Yoshida, S.; Matsuoka, K.; Ichimura, K.; Ito, G.; Yasuda, K.; Kakubata, H.; Miyashita, M.; Takubo, K.; Saka, M.; Seki, K. [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka Japan (Japan); Ajimura, S.; Umehara, S.; Nakatani, N. [Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka Ibaraki Osaka Japan (Japan); Tamagawa, Y.; Ogawa, I. [Graduate School of Engineering, University of Fukui,Fukui (Japan); Fushimi, K. [Faculty of Integrated Arts and Science, Tokushima University, Tokushima (Japan); Hazama, R. [Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima (Japan); Ohsumi, H. [Faculty of Culture and Education, Saga University, Saga (Japan)

    2011-10-21T23:59:59.000Z

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

  4. Neutrino oscillations refitted

    E-Print Network [OSTI]

    D. V. Forero; M. Tortola; J. W. F. Valle

    2014-11-21T23:59:59.000Z

    Here we update our previous global fit of neutrino oscillations by including the recent results which have appeared since the Neutrino-2012 conference. These include the measurements of reactor anti-neutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle $\\theta_{23}$ is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with emphasis on the increasing sensitivity to the CP phase, thanks to the interplay between accelerator and reactor data. In the appendix we present the updated results obtained after the inclusion of new reactor data presented at the Neutrino 2014 conference. We discuss their impact on the global neutrino analysis.

  5. Measurement of the Inclusive Leptonic Asymmetry in Top-Quark Pairs that Decay to Two Charged Leptons at CDF

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We measure the inclusive forward–backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton–antiproton collisions and decaying to final states that contain two charged leptons (electrons ...

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

    SciTech Connect (OSTI)

    Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States)

    2014-06-24T23:59:59.000Z

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

  7. Sterile Neutrino Fits to Short-Baseline Neutrino Oscillation Measurements

    E-Print Network [OSTI]

    Conrad, J. M.

    2013-01-01T23:59:59.000Z

    This paper reviews short-baseline oscillation experiments as interpreted within the context of one, two, and three sterile neutrino models associated with additional neutrino mass states in the ~1?eV range. Appearance and ...

  8. GENIUS project, neutrino oscillations and Cosmology: neutrinos reveal their nature?

    E-Print Network [OSTI]

    M. Czakon; J. Studnik; M. Zralek; J. Gluza

    2000-05-17T23:59:59.000Z

    The neutrinoless double beta decay as well as any other laboratory experiment has not been able to answer the question of the neutrino's nature. Hints on the answer are available when neutrino oscillations and $(\\beta\\beta)_{0 \

  9. Constraints on the tau neutrino mass and mixing from precise measurements of tau decay rates

    E-Print Network [OSTI]

    John Swain; Lucas Taylor

    1996-10-04T23:59:59.000Z

    We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the partial widths of tau lepton decays, in particular: tau -> e nu nu_tau, tau -> mu nu nu_tau, tau -> pi nu_tau, tau -> K nu_tau. We present predictions for the tau decay widths, allowing for a non-zero tau neutrino mass, m(nu_tau), and for mixing with a neutrino of mass m(nu_L) > M_Z/2, which is parametrised using a Cabibbo-like mixing angle, theta_L. By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90% confidence level: m(nu_tau) < 42 MeV and sin^2(theta_L) < 0.014.

  10. High energy neutrino emission from the earliest gamma-ray bursts

    SciTech Connect (OSTI)

    Gao Shan; Toma, Kenji; Meszaros, Peter [Department of Physics, Department of Astronomy and Astrophysics, Center for Particle Astrophysics, Pennsylvania State University, University Park, 16802 (United States)

    2011-05-15T23:59:59.000Z

    We discuss the high energy neutrino emission from gamma-ray bursts resulting from the earliest generation (''population III'') stars forming in the Universe, whose core collapses into a black hole. These gamma-ray bursts are expected to produce a highly relativistic, magnetically dominated jet, where protons can be accelerated to ultrahigh energies. These interact with the photons produced by the jet, leading to ultrahigh energy photomeson neutrinos as well as secondary leptons and photons. The photon luminosity and the shock properties, and thus the neutrino spectrum, depend on the mass of the black holes as well as on the density of the surrounding external gas. We calculate the individual source neutrino spectral fluxes and the expected diffuse neutrino flux for various source parameters and evolution scenarios. Both the individual and diffuse signals appear detectable in the 1-300 PeV range with current and planned neutrino detectors such as IceCube and ARIANNA, provided the black hole mass is in excess of 30-100 solar masses. This provides a possible test for the debated mass of the progenitor stellar objects, as well as a probe for the early cosmological environment and the formation rate of the earliest structures.

  11. Phenomenology of TeV Right-handed Neutrino and the Dark Matter Model

    E-Print Network [OSTI]

    Kingman Cheung; Osamu Seto

    2004-03-08T23:59:59.000Z

    In a model of TeV right-handed (RH) neutrino by Krauss, Nasri, and Trodden, the sub-eV scale neutrino masses are generated via a 3-loop diagram with the vanishing see-saw mass forbidden by a discrete symmetry, and the TeV mass RH neutrino is simultaneously a novel candidate for the cold dark matter. However, we show that with a single RH neutrino it is not possible to generate two mass-square differences as required by the oscillation data. We extend the model by introducing one more TeV RH neutrino and show that it is possible to satisfy the oscillation pattern within the modified model. After studying in detail the constraints coming from the dark matter, lepton flavor violation and the muon anomalous magnetic moment, and the neutrinoless double beta decay, we explore the parameter space and derive predictions of the model. Finally, we study the production and decay signatures of the TeV RH neutrinos at TeV $e^+ e^-/\\mu^+ \\mu^-$ colliders.

  12. The NESSiE way to searches for sterile neutrinos at FNAL

    E-Print Network [OSTI]

    L. Stanco; A. Anokhina; A. Bagulya; M. Benettoni; P. Bernardini; R. Brugnera; M. Calabrese; A. Cecchetti; S. Cecchini; M. Chernyavskiy; P. Creti; F. Dal Corso; O. Dalkarov; A. Del Prete; G. De Robertis; M. De Serio; L. Degli Esposti; D. Di Ferdinando; S. Dusini; T. Dzhatdoev; C. Fanin; R. A. Fini; G. Fiore; A. Garfagnini; S. Golovanov; M. Guerzoni; B. Klicek; U. Kose; K. Jakovcic; G. Laurenti; I. Lippi; F. Loddo; A. Longhin; M. Malenica; G. Mancarella; G. Mandriol; A. Margiotta; G. Marsella; N. Mauri; E. Medinaceli; A. Mengucci; R. Mingazheva; O. Morgunova; M. T. Muciaccia; M. Nessi; D. Orecchini; A. Paoloni; G. Papadia; L. Paparella; L. Pasqualini; A. Pastore; L. Patrizii; N. Polukhina; M. Pozzato; M. Roda; T. Roganova; G. Rosa; Z. Sahnoun; S. Simone; C. Sirignano; G. Sirri; M. Spurio; N. Starkov; M. Stipcevic; A. Surdo; M. Tenti; V. Togo; M. Ventura; M. Vladymyrov

    2014-10-15T23:59:59.000Z

    Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $\\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. Its recent proposal refers to the use of magnetic spectrometers at two different sites, Near and Far ones. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the undergoing project of a multi-site Liquid-Argon detectors at FNAL. The experiment to be possibly setup at Booster will allow to definitively clarify the current $\

  13. The Neutrino Eye: A Megaton Low Energy Neutrino

    E-Print Network [OSTI]

    Learned, John

    from WIMPS and gamma ray bursts, and upon real time counting of solar neutrinos, are all from sensi­ tivity, and conduct a watch for for neutrino correlates to sporadic phenomenon such as gamma ray bursts. The main thrust would be to detect actual muon neutrino appearance as well as disappearance

  14. Underground Neutrino Detectors for Particle and Astroparticle Science the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER)

    E-Print Network [OSTI]

    Rubbia, A

    2009-01-01T23:59:59.000Z

    The current focus of the CERN program is the Large Hadron Collider (LHC), however, CERN is engaged in long baseline neutrino physics with the CNGS project and supports T2K as recognized CERN RE13, and for good reasons: a number of observed phenomena in high-energy physics and cosmology lack their resolution within the Standard Model of particle physics; these puzzles include the origin of neutrino masses, CP-violation in the leptonic sector, and baryon asymmetry of the Universe. They will only partially be addressed at LHC. A positive measurement of $\\sin^22\\theta_{13}>0.01$ would certainly give a tremendous boost to neutrino physics by opening the possibility to study CP violation in the lepton sector and the determination of the neutrino mass hierarchy with upgraded conventional super-beams. These experiments (so called ``Phase II'') require, in addition to an upgraded beam power, next generation very massive neutrino detectors with excellent energy resolution and high detection efficiency in a wide neutrin...

  15. Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS

    E-Print Network [OSTI]

    Sanjib Kumar Agarwalla; Sandhya Choubey; Suprabh Prakash

    2015-01-04T23:59:59.000Z

    A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity towards establishing CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 5sigma sensitivity to CP violation for 48% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 5sigma sensitivity for 34% of true values of deltaCP. On the other hand, for the discovery of a non-maximal theta23 and its octant, the 200 km baseline option with 7nu+3nubar run-plan performs significantly better than the other baselines. A 5sigma determination of a non-maximal theta23 can be made if the true value of sin^2theta23 lesssim 0.45 or sin^2theta23 gtrsim 0.57. The octant of theta23 could be resolved at 5sigma if the true value of sin^2theta23 lesssim 0.43 or gtrsim 0.59, irrespective of deltaCP.

  16. The heavy top quark and supersymmetry

    SciTech Connect (OSTI)

    Hall, L.J. [Lawrence Berkeley Lab., CA (United States); [Univ. of California, Berkeley, CA (United States)

    1997-01-01T23:59:59.000Z

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

  17. A Dynamical Framework for KeV Dirac Neutrino Warm Dark Matter

    E-Print Network [OSTI]

    Dean J. Robinson; Yuhsin Tsai

    2014-08-06T23:59:59.000Z

    If the source of the reported $3.5$ keV x-ray line is a sterile neutrino, comprising an $\\mathcal{O}(1)$ fraction of the dark matter (DM), then it exhibits the property that its mass times mixing angle is $\\sim \\mbox{few} \\times 10^{-2}$ eV, a plausible mass scale for the active neutrinos. This property is a common feature of Dirac neutrino mixing. We present a framework that dynamically produces light active and keV sterile Dirac neutrinos, with appropriate mixing angles to be the x-ray line source. The central idea is that the right-handed active neutrino is a composite state, while elementary sterile neutrinos gain keV masses similarly to the quarks in extended Technicolor. The entire framework is fixed by just two dynamical scales and may automatically exhibit a warm dark matter (WDM) production mechanism -- dilution of thermal relics from late decays of a heavy composite neutrino -- such that the keV neutrinos may comprise an $\\mathcal{O}(1)$ fraction of the DM. In this framework, the WDM is typically quite cool and within structure formation bounds, with temperature $\\sim \\mbox{few}\\times 10^{-2}~T_\

  18. Neutrino oscillations beyond two flavours

    E-Print Network [OSTI]

    E. Kh. Akhmedov

    2002-07-29T23:59:59.000Z

    I review some theoretical aspects of neutrino oscillations in the case when more than two neutrino flavours are involved. These include: approximate analytic solutions for 3-flavour (3f) oscillations in matter; matter effects in nu_mu - nu_tau oscillations; 3f effects in oscillations of solar, atmospheric, reactor and supernova neutrinos and in accelerator long-baseline experiments; CP and T violation in neutrino oscillations in vacuum and in matter; the problem of U_{e3}; 4f oscillations.

  19. Neutrino dispersion in magnetized plasma

    E-Print Network [OSTI]

    N. V. Mikheev; E. N. Narynskaya

    2008-12-02T23:59:59.000Z

    The neutrino dispersion in the charge symmetric magnetized plasma is investigated. We have studied the plasma contribution into the additional energy of neutrino and obtained the simple expression for it. We consider in detail the neutrino self-energy under physical conditions of weak field, moderate field and strong field limits. It is shown that our result for neutrino dispersion in moderate magnetic field differ substantially from the previous one in the literature.

  20. Determining the neutrino mass hierarchy

    SciTech Connect (OSTI)

    Parke, Stephen J.; /Fermilab

    2006-07-01T23:59:59.000Z

    In this proceedings I review the physics that future experiments will use to determine the neutrino mass hierarchy.

  1. Perspectives on neutrino telescopes 2009

    SciTech Connect (OSTI)

    Quigg, Chris; /Fermilab /Karlsruhe U., TTP

    2009-04-01T23:59:59.000Z

    Remarks at the roundtable on plans for the future at the XIII International Workshop on Neutrino Telescopes.

  2. On the Relation between the True Directions of Neutrinos and the Reconstructed Directions of Neutrinos in L/E Analysis Performed by Super-Kamiokande Collaboration Part1

    E-Print Network [OSTI]

    Konishi, E; Galkin, V I; Ishiwata, M; Nakamura, I; Takahashi, N; Kato, M; Misaki, A

    2011-01-01T23:59:59.000Z

    It should be regarded that the confirmation of the maximum oscillation in neutrino oscillation through L/E analysis by Super-Kamiokande is a logical consequence of their establishment on the existence of neutrino oscillation through the analysis of the zenith angle distribution for atmospheric neutrino events. In the present paper (Part1) with the computer numerical experiment, we examine the assumption made by Super-Kamiokande Collaboration that the direction of the incident neutrino is approximately the same as that of the produced lepton, which is the cornerstone in their L/E analysis, and we find this approximation does not hold even approximately. In a subsequent paper (Part2), we apply the results from Figures 16, 17, 18 and 19 to L/E analysis and conclude that one cannot obtain the maximum oscillation in L/E analysis in the single ring muon events due to quasi-elastic scattering reported by Super-Kamiokande which shows strongly the oscillation pattern from the neutrino oscillation.

  3. On the Relation between the True Directions of Neutrinos and the Reconstructed Directions of Neutrinos in L/E Analysis Performed by Super-Kamiokande Collaboration Part1

    E-Print Network [OSTI]

    E. Konishi; Y. Minorikawa; V. I. Galkin; M. Ishiwata; I. Nakamura; N. Takahashi; M. Kato; A. Misaki

    2011-08-04T23:59:59.000Z

    It should be regarded that the confirmation of the maximum oscillation in neutrino oscillation through L/E analysis by Super-Kamiokande is a logical consequence of their establishment on the existence of neutrino oscillation through the analysis of the zenith angle distribution for atmospheric neutrino events. In the present paper (Part1) with the computer numerical experiment, we examine the assumption made by Super-Kamiokande Collaboration that the direction of the incident neutrino is approximately the same as that of the produced lepton, which is the cornerstone in their L/E analysis, and we find this approximation does not hold even approximately. In a subsequent paper (Part2), we apply the results from Figures 16, 17, 18 and 19 to L/E analysis and conclude that one cannot obtain the maximum oscillation in L/E analysis in the single ring muon events due to quasi-elastic scattering reported by Super-Kamiokande which shows strongly the oscillation pattern from the neutrino oscillation.

  4. Neutrino oscillations: theory and phenomenology

    E-Print Network [OSTI]

    E. Kh. Akhmedov

    2006-10-05T23:59:59.000Z

    A brief overview of selected topics in the theory and phenomenology of neutrino oscillations is given. These include: oscillations in vacuum and in matter; phenomenology of 3-flavour neutrino oscillations and effective 2-flavour approximations; CP and T violation in neutrino oscillations in vacuum and in matter; matter effects on \

  5. Supernova Neutrinos Detection On Earth

    E-Print Network [OSTI]

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

    2009-05-12T23:59:59.000Z

    In this paper, we first discuss the detection of supernova neutrino on Earth. Then we propose a possible method to acquire information about $\\theta_{13}$ smaller than $1.5^\\circ$ by detecting the ratio of the event numbers of different flavor supernova neutrinos. Such an sensitivity cannot yet be achieved by the Daya Bay reactor neutrino experiment.

  6. Solar Neutrino Matter Effects Redux

    E-Print Network [OSTI]

    A. B. Balantekin; A. Malkus

    2011-12-19T23:59:59.000Z

    Following recent low-threshold analysis of the Sudbury Neutrino Observatory and asymmetry measurements of the BOREXINO Collaboration of the solar neutrino flux, we revisit the analysis of the matter effects in the Sun. We show that solar neutrino data constrains the mixing angle $\\theta_{13}$ poorly and that subdominant Standard Model effects can mimic the effects of the physics beyond the Standard Model.

  7. Heavy Higgs signal-background interference in gg --> VV in the Standard Model plus real singlet

    E-Print Network [OSTI]

    Kauer, Nikolas

    2015-01-01T23:59:59.000Z

    For the Standard Model extended with a real scalar singlet field, the modification of the heavy Higgs signal due to interference with the continuum background and the off-shell light Higgs contribution is studied for gg --> ZZ, WW --> 4 lepton processes at the Large Hadron Collider. A public program that allows to simulate the full interference is presented.

  8. Neutrino oscillations: brief history and present status

    E-Print Network [OSTI]

    Bilenky, S M

    2014-01-01T23:59:59.000Z

    A brief review of the problem of neutrino masses and oscillations is given. In the beginning we present an early history of neutrino masses, mixing and oscillations. Then we discuss all possibilities of neutrino masses and mixing (neutrino mass terms). The phenomenology of neutrino oscillations in vacuum is considered in some details. We present also the neutrino oscillation data and the seesaw mechanism of the neutrino mass generation.

  9. Optimisation of future long baseline neutrino experiments

    E-Print Network [OSTI]

    Olga Mena

    2008-09-28T23:59:59.000Z

    The aim of this talk is to review near and far future long baseline neutrino experiments as superbeams, beta-Beams and neutrino factories, comparing their sensitivities to the unknown parameters in the neutrino oscillation sector. We focus on the extraction of the neutrino mass hierarchy, exploring alternatives to the commonly used neutrino-antineutrino comparison. Special attention to a new concept of neutrino factory design, the low energy neutrino factory, is given.

  10. Neutrino oscillations and supernovae

    E-Print Network [OSTI]

    D. V. Ahluwalia-Khalilova

    2004-04-02T23:59:59.000Z

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

  11. Plasmon decay to a neutrino pair via neutrino electromagnetic moments in a strongly magnetized medium

    E-Print Network [OSTI]

    A. V. Borisov; P. E. Sizin

    2014-06-12T23:59:59.000Z

    We calculate the neutrino luminosity of a degenerate electron gas in a strong magnetic field via plasmon decay to a neutrino pair due to neutrino electromagnetic moments and obtain the relative upper bounds on the effective neutrino magnetic moment.

  12. Probing Late Neutrino Mass Properties With SupernovaNeutrinos

    SciTech Connect (OSTI)

    Baker, Joseph; Goldberg, Haim; Perez, Gilad; Sarcevic, Ina

    2007-08-08T23:59:59.000Z

    Models of late-time neutrino mass generation contain new interactions of the cosmic background neutrinos with supernova relic neutrinos (SRNs). Exchange of an on-shell light scalar may lead to significant modification of the differential SRN flux observed at earth. We consider an Abelian U(1) model for generating neutrino masses at low scales, and show that there are cases for which the changes induced in the flux allow one to distinguish the Majorana or Dirac nature of neutrinos, as well as the type of neutrino mass hierarchy (normal or inverted or quasi-degenerate). In some region of parameter space the determination of the absolute values of the neutrino masses is also conceivable. Measurements of the presence of these effects may be possible at the next-generation water Cerenkov detectors enriched with Gadolinium, or a 100 kton liquid argon detector.

  13. Inverse neutrinoless double beta decay revisited: Neutrinos, Higgs triplets, and a muon collider

    SciTech Connect (OSTI)

    Rodejohann, Werner [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)

    2010-06-01T23:59:59.000Z

    We revisit the process of inverse neutrinoless double beta decay (e{sup -}e{sup -{yields}}W{sup -}W{sup -}) at future linear colliders. The cases of Majorana neutrino and Higgs triplet exchange are considered. We also discuss the processes e{sup -{mu}-{yields}}W{sup -}W{sup -} and {mu}{sup -{mu}-{yields}}W{sup -}W{sup -}, which are motivated by the possibility of muon colliders. For heavy neutrino exchange, we show that masses up to 10{sup 6} (10{sup 5}) GeV could be probed for ee and e{mu} machines, respectively. The stringent limits for mixing of heavy neutrinos with muons render {mu}{sup -{mu}-{yields}}W{sup -}W{sup -} less promising, even though this process is not constrained by limits from neutrinoless double beta decay. If Higgs triplets are responsible for inverse neutrinoless double beta decay, observable signals are only possible if a very narrow resonance is met. We also consider unitarity aspects of the process in case both Higgs triplets and neutrinos are exchanged. An exact seesaw relation connecting low energy data with heavy neutrino and triplet parameters is found.

  14. The neutrino signal at HALO: learning about the primary supernova neutrino fluxes and neutrino properties

    SciTech Connect (OSTI)

    Väänänen, Daavid; Volpe, Cristina, E-mail: vaananen@ipno.in2p3.fr, E-mail: volpe@ipno.in2p3.fr [Institut de Physique Nucléaire, F-91406 Orsay cedex, CNRS/IN2P3 and University of Paris-XI (France)

    2011-10-01T23:59:59.000Z

    Core-collapse supernova neutrinos undergo a variety of phenomena when they travel from the high neutrino density region and large matter densities to the Earth. We perform analytical calculations of the supernova neutrino fluxes including collective effects due to the neutrino-neutrino interactions, the Mikheev-Smirnov-Wolfenstein (MSW) effect due to the neutrino interactions with the background matter and decoherence of the wave packets as they propagate in space. We predict the numbers of one- and two-neutron charged and neutral-current electron-neutrino scattering on lead events. We show that, due to the energy thresholds, the ratios of one- to two-neutron events are sensitive to the pinching parameters of neutrino fluxes at the neutrinosphere, almost independently of the presently unknown neutrino properties. Besides, such events have an interesting sensitivity to the spectral split features that depend upon the presence/absence of energy equipartition among neutrino flavors. Our calculations show that a lead-based observatory like the Helium And Lead Observatory (HALO) has the potential to pin down important characteristics of the neutrino fluxes at the neutrinosphere, and provide us with information on the neutrino transport in the supernova core.

  15. Examining the geometrical model with inverted mass hierarchy for neutrinos

    SciTech Connect (OSTI)

    Honda, Mizue; Tanimoto, Morimitsu [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Department of Physics, Niigata University, Niigata 950-2181 (Japan)

    2007-05-01T23:59:59.000Z

    The comprehensive analyses are presented in the model with the inverted mass hierarchy for neutrinos, which follows from a geometrical structure of a (1+5) dimensional space-time where two extra dimensions are compactified on the T{sup 2}/Z{sub 3} orbifold. The model gives two large lepton flavor mixings due to the S{sub 3} structure in the (1+5) dimensional space-time. It also predicts the lightest neutrino mass as m{sub 3}=(1-50)x10{sup -5} eV and the effective neutrino mass responsible for neutrinoless double beta decays as {sub ee}{approx_equal}50 meV. The low energy CP violation, J{sub CP} could be 0.02. On the other hand, the observed baryon asymmetry in the present universe is produced by the nonthermal leptogenesis, which works even at the reheating temperature T{sub R}=10{sup 4}-10{sup 6} GeV. The correlation between the baryon asymmetry and the low energy CP violation is examined in this model.

  16. Neutrino Oscillations and Blazars

    E-Print Network [OSTI]

    Karl Mannheim

    1999-01-25T23:59:59.000Z

    Three independent predictions follow from postulating the existence of protons co-accelerated with electrons in extragalactic jets (i) multi-TeV gamma ray emission from nearby blazars, (ii) extragalactic cosmic ray protons up to 10^20 eV, and (iii) extragalactic neutrinos up to 5 10^18 eV. Recent gamma ray observations of Mrk 421 and Mrk 501 employing the air-Cerenkov technique are consistent with the predicted gamma ray spectrum, if one corrects for pair attenuation on the infrared background. Prediction (ii) is consistent with cosmic ray data, if one requires that jets are responsible for at least a sizable fraction of the extragalactic gamma ray background. With kubic kilometer neutrino telescopes, it will be possible to test (iii), although the muon event rates are rather low. Neutrino oscillations can increase the event rate by inducing tau-cascades removing the Earth shadowing effect.

  17. Short Baseline Neutrino Oscillation Experiments

    E-Print Network [OSTI]

    Katori, Teppei

    2014-01-01T23:59:59.000Z

    Series of short baseline neutrino oscillation experiments provided unexpected results, and now they are called short baseline anomalies, and all indicates an existence of sterile neutrinos with a mass scale around 1~eV. The signals of short baseline anomalies are reported from 4 different classes of experiments. However, at this moment, there is no convincing theoretical model to explain such sterile neutrinos, and a single experiment to confirm 1~eV sterile neutrinos may be challenging. In this short note, we describe classes of short baseline neutrino oscillation experiments and their goals.

  18. Riddle of the Neutrino Mass

    E-Print Network [OSTI]

    Smirnov, A Yu

    2015-01-01T23:59:59.000Z

    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.

  19. Are neutrinos their own antiparticles?

    SciTech Connect (OSTI)

    Kayser, Boris; /Fermilab

    2009-03-01T23:59:59.000Z

    We explain the relationship between Majorana neutrinos, which are their own antiparticles, and Majorana neutrino masses. We point out that Majorana masses would make the neutrinos very distinctive particles, and explain why many theorists strongly suspect that neutrinos do have Majorana masses. The promising approach to confirming this suspicion is to seek neutrinoless double beta decay. We introduce a toy model that illustrates why this decay requires nonzero neutrino masses, even when there are both right-handed and left-handed weak currents.

  20. Test of lepton universality and search for lepton flavor violation in Upsilon(1S,2S,3S) decays at CLEO

    E-Print Network [OSTI]

    Istvan Danko; for the CLEO Collaboration

    2006-01-18T23:59:59.000Z

    We present the analysis technique and preliminary results of two ongoing analyses at CLEO which put lepton universality and lepton flavor conservation to the test in Upsilon decays.