WorldWideScience

Sample records for neutrino mass model

  1. Unconventional model of neutrino masses

    Science.gov (United States)

    Georgi, Howard M.; Glashow, Sheldon Lee; Nussinov, Shmuel

    1981-12-01

    Gelmini and Roncadelli have proposed a model of neutrino masses in which B- L symmetry is spontaneously broken by a small vacuum expectation value of a Higgs triplet. We give an exegesis of this model. We show that the massive neutrinos in this model cannot be cosmologically relevant today and that conflicting analyses of double beta decay experiments can be reconciled.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  3. Leptogenesis models and neutrino mass constraints

    Indian Academy of Sciences (India)

    Following the recent convincing evidence for neutrino masses, leptogenesis [1] has become a well motivated possible explanation of the origin of the baryon asymmetry of the universe. In these proceedings, in the framework of the usual seesaw model with three right-handed neutrinos ('Type-I' seesaw model [2]), we will ...

  4. Models of neutrino masses and baryogenesis

    Indian Academy of Sciences (India)

    ble to discriminate different classes of models of neutrino masses. While see-saw mechanism and the triplet Higgs mechanism are preferred, the Zee-type radiative models and the К-parity breaking mod- els requires additional inputs to generate baryon asymmetry of the universe during the electroweak phase transition.

  5. Models of neutrino masses and baryogenesis

    Indian Academy of Sciences (India)

    exp[-О¼ М ] where the potential or the free energy О¼ is related to the mass of the sphaleron field. ... The chemical potentials of the neutrinos always enter as a sum and for that reason we can consider it as one .... the mass terms of the singlet right handed neutrinosЖ and the Yukawa couplings of these fields with the light ...

  6. Neutrino mass

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1992-01-01

    Despite intensive experimental work since the neutrino's existence was proposed by Pauli 60 years ago, and its first observation by Reines and Cowan almost 40 years ago, the neutrino's fundamental properties remain elusive. Among those properties are the masses of the three known flavors, properties under charge conjugation, parity and time-reversal, and static and dynamic electromagnetic moments. Mass is perhaps the most fundamental, as it constrains the other properties. The present status of the search for neutrino mass is briefly reviewed

  7. Unification of gauge couplings in radiative neutrino mass models

    DEFF Research Database (Denmark)

    Hagedorn, Claudia; Ohlsson, Tommy; Riad, Stella

    2016-01-01

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

  8. Models of neutrino masses and baryogenesis

    Indian Academy of Sciences (India)

    Majorana masses of the neutrino implies lepton number violation and is intimately related to the lepton asymmetry of the universe, which gets related to the baryon asymmetry of the universe in the presence of the sphalerons during the electroweak phase transition. Assuming that the baryon asymmetry of the universe is ...

  9. Neutrino Mass Models: Impact of non-zero reactor angle

    OpenAIRE

    King, Stephen F.

    2011-01-01

    In this talk neutrino mass models are reviewed and the impact of a non-zero reactor angle and other deviations from tri-bimaximal mixing are discussed. We propose some benchmark models, where the only way to discriminate between them is by high precision neutrino oscillation experiments.

  10. Model independent explorations of Majorana neutrino mass origins

    Science.gov (United States)

    Jenkins, James Phearl, Jr.

    The recent observation of nonzero neutrino mass is the first concrete indication of physics beyond the Standard Model. Their properties, unique among the other fermions, leads naturally to the idea of a Majorana neutrino mass term. Despite the strong theoretical prejudice toward this concept, it must be tested experimentally. This is indeed possible in the context of next generation experiments. Unfortunately, the scale of neutrino mass generation may be too large to explore directly, but useful information may still be extracted from independent experimental channels. Here I survey various model independent probes of Majorana neutrino mass origins. A brief introduction to the concepts relevant to the analysis is followed by a discussion of the physical ranges of neutrino mass and mixing parameters within the context of standard and non-standard interactions. Armed with this, I move on to systematically analyze the properties of radiatively generated neutrino masses induced by nonrenormalizable lepton number violating effective operators of mass dimensions five through eleven. By fitting these to the observed light mass scale, I extract predictions for neutrino mixing as well as neutrinoless double beta decay, rare meson/tau decays and collider phenomenology. I find that many such models are already constrained by current data and many more will be probed in the near future. I then move on demonstrate the utility of a low scale see saw mechanism via a viable 3+2+1 sterile neutrino model that satisfies all oscillation data as well as solves problems associated with supernova kicks and heavy element nucleosynthesis. From this I extract predictions for tritium and neutrinoless double beta decay searches. This is supplemented throughout by descriptions of practical limitations in addition to suggestions for future work.

  11. Gravitational leptogenesis, reheating, and models of neutrino mass

    Science.gov (United States)

    Adshead, Peter; Long, Andrew J.; Sfakianakis, Evangelos I.

    2018-02-01

    Gravitational leptogenesis refers to a class of baryogenesis models in which the matter-antimatter asymmetry of the Universe arises through the standard model lepton-number gravitational anomaly. In these models chiral gravitational waves source a lepton asymmetry in standard model neutrinos during the inflationary epoch. We point out that gravitational leptogenesis can be successful in either the Dirac or Majorana neutrino mass scenario. In the Dirac mass scenario, gravitational leptogenesis predicts a relic abundance of sterile neutrinos that remain out of equilibrium, and the lepton asymmetry carried by the standard model sector is unchanged. In the Majorana mass scenario, the neutrinos participate in lepton-number-violating interactions that threaten to wash out the lepton asymmetry during postinflationary reheating. However, we show that a complete (exponential) washout of the lepton asymmetry is prevented if the lepton-number-violating interactions go out of equilibrium before all of the standard model Yukawa interactions come into equilibrium. The baryon and lepton asymmetries carried by right-chiral quarks and leptons are sequestered from the lepton-number violation, and the washout processes only suppress the predicted baryon asymmetry by a factor of ɛw .o .=±O (0.1 ). The sign of ɛw .o . depends on the model parameters in such a way that a future measurement of the primordial gravitational wave chirality would constrain the scale of lepton-number violation (heavy Majorana neutrino mass).

  12. Models of Neutrino Masses: Anarchy versus Hierarchy

    Science.gov (United States)

    Altarelli, Guido; Feruglio, Ferruccio; Masina, Isabella

    2003-01-01

    We present a quantitative study of the ability of models with different levels of hierarchy to reproduce the solar neutrino solutions, in particular the LA solution. As a flexible testing ground we consider models based on SU(5) × U(1)F. In this context, we have made statistical simulations of models with different patterns from anarchy to various types of hierarchy: normal hierarchical models with and without automatic suppression of the 23 (sub)determinant and inverse hierarchy models. We find that, not only for the LOW or VO solutions, but even in the LA case, the hierarchical models have a significantly better success rate than those based on anarchy. The normal hierarchy and the inverse hierarchy models have comparable performances in models with see-saw dominance, while the inverse hierarchy models are particularly good in the no see-saw versions. As a possible distinction between these categories of models, the inverse hierarchy models favour a maximal solar mixing angle and their rate of success drops dramatically as the mixing angle decreases, while normal hierarchy models are far more stable in this respect.

  13. Models of Neutrino Masses Anarchy versus Hierarchy

    CERN Document Server

    Altarelli, Guido; Masina, I; Altarelli, Guido; Feruglio, Ferruccio; Masina, Isabella

    2003-01-01

    We present a quantitative study of the ability of models with different levels of hierarchy to reproduce the solar neutrino solutions, in particular the LA solution. As a flexible testing ground we consider models based on SU(5)xU(1)_F. In this context, we have made statistical simulations of models with different patterns from anarchy to various types of hierachy: normal hierarchical models with and without automatic suppression of the 23 (sub)determinant and inverse hierarchy models. We find that, not only for the LOW or VO solutions, but even in the LA case, the hierarchical models have a significantly better success rate than those based on anarchy. The normal hierachy and the inverse hierarchy models have comparable performances in models with see-saw dominance, while the inverse hierarchy models are particularly good in the no see-saw versions. As a possible distinction between these categories of models, the inverse hierarchy models favour a maximal solar mixing angle and their rate of success drops dr...

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

    NARCIS (Netherlands)

    Nieuwenhuizen, T.M.

    2016-01-01

    The dark matter in the galaxy cluster Abell 1689 is modelled as an isothermal sphere of neutrinos. New data on the 2d mass density allow an accurate description of its core and halo. The model has no "missing baryon problem" and beyond 2.1 Mpc the baryons have the cosmic mass abundance. Combination

  15. Neutrino mass and physics beyond the Standard Model

    International Nuclear Information System (INIS)

    Hosteins, P.

    2007-09-01

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

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

    Science.gov (United States)

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

    2013-05-24

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

  17. Neutrino masses and their ordering: global data, priors and models

    Science.gov (United States)

    Gariazzo, S.; Archidiacono, M.; de Salas, P. F.; Mena, O.; Ternes, C. A.; Tórtola, M.

    2018-03-01

    We present a full Bayesian analysis of the combination of current neutrino oscillation, neutrinoless double beta decay and Cosmic Microwave Background observations. Our major goal is to carefully investigate the possibility to single out one neutrino mass ordering, namely Normal Ordering or Inverted Ordering, with current data. Two possible parametrizations (three neutrino masses versus the lightest neutrino mass plus the two oscillation mass splittings) and priors (linear versus logarithmic) are exhaustively examined. We find that the preference for NO is only driven by neutrino oscillation data. Moreover, the values of the Bayes factor indicate that the evidence for NO is strong only when the scan is performed over the three neutrino masses with logarithmic priors; for every other combination of parameterization and prior, the preference for NO is only weak. As a by-product of our Bayesian analyses, we are able to (a) compare the Bayesian bounds on the neutrino mixing parameters to those obtained by means of frequentist approaches, finding a very good agreement; (b) determine that the lightest neutrino mass plus the two mass splittings parametrization, motivated by the physical observables, is strongly preferred over the three neutrino mass eigenstates scan and (c) find that logarithmic priors guarantee a weakly-to-moderately more efficient sampling of the parameter space. These results establish the optimal strategy to successfully explore the neutrino parameter space, based on the use of the oscillation mass splittings and a logarithmic prior on the lightest neutrino mass, when combining neutrino oscillation data with cosmology and neutrinoless double beta decay. We also show that the limits on the total neutrino mass ∑ mν can change dramatically when moving from one prior to the other. These results have profound implications for future studies on the neutrino mass ordering, as they crucially state the need for self-consistent analyses which explore the

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

    Energy Technology Data Exchange (ETDEWEB)

    Hosteins, P

    2007-09-15

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

  19. Neutrino masses

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Postulated in the early days of quantum mechanics by Wolfgang Pauli to make energy-momentum conservation in nuclear beta decay come out right, the neutrino has never strayed far from physicists' attention. The Moriond Workshop on Massive Neutrinos in Particle Physics and Astrophysics held recently in the French Alps showed that more than half a century after Pauli's prediction, the neutrino stubbornly refuses to yield up all its secrets

  20. Anarchy of Neutrino Mass

    Science.gov (United States)

    Haba, Naoyuki; Murayama, Hitoshi

    We have advocated a new approach to build models of fermion masses and mixings, namely anarchy. The approach relies only on the approximate flavor symmetries, and scan the O(1) coefficients randomly. The randomness in O(1) coupling constants is indeed what one expects in models which are sufficiently complicated or which have a large number of fields mixed with each other. Assuming there is no physical distinction among three generations of neutrinos, the near-maximal mixings, as observed in the atmospheric neutrino data and as required in the LMA solution to the solar neutrino problem, are highly probable.

  1. Physics of the neutrino mass

    International Nuclear Information System (INIS)

    Mohapatra, R N

    2004-01-01

    Recent neutrino oscillation experiments have yielded valuable information on the nature of neutrino masses and mixings and qualify as the first evidence for physics beyond the standard model. Even though we are far from a complete understanding of the new physics implied by them, there are many useful hints. As the next precision era in neutrino physics is about to be launched, we review the physics of neutrino mass: what we have learned and what we are going to learn

  2. ABSOLUTE NEUTRINO MASSES

    DEFF Research Database (Denmark)

    Schechter, J.; Shahid, M. N.

    2012-01-01

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

  3. Neutrino mass: Recent results

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1989-01-01

    Some recent developments in the experimental search for neutrino mass are discussed. Simpson and Hime report finding new evidence for a 17-keV neutrino in the β decay of 3 H and 35 S. New data from Los Alamos on the electron neutrino mass as measured in tritium beta decay give an upper limit of 13.5 eV at the 95% confidence level. This result is not consistent with the long-standing ITEP result of 26(5) eV within a ''model-independent'' range of 17 to 40 eV. It now appears that the electron neutrino is not sufficiently massive to close the universe by itself. 38 refs., 1 figs., 2 tabs

  4. The B - L scotogenic models for Dirac neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weijian [North China Electric Power University, Department of Physics, Baoding (China); Wang, Ruihong [Hebei Agricultural University, College of Information Science and Technology, Baoding (China); Han, Zhi-Long [University of Jinan, School of Physics and Technology, Jinan, Shandong (China); Han, Jin-Zhong [Zhoukou Normal University, School of Physics and Telecommunications Engineering, Zhoukou, Henan (China)

    2017-12-15

    We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of U(1){sub B-L} extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by the anomaly free condition and the new particles may have exotic B - L charges so that the direct SM Yukawa mass term anti ν{sub L}ν{sub R}φ{sup 0} and the Majorana mass term (m{sub N}/2)ν{sub R}{sup C}ν{sub R} are naturally forbidden. After the spontaneous breaking of the U(1){sub B-L} symmetry, the discrete Z{sub 2} or Z{sub 3} symmetry appears as the residual symmetry and gives rise to the stability of intermediate fields as DM candidates. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed. (orig.)

  5. The B-L scotogenic models for Dirac neutrino masses

    Science.gov (United States)

    Wang, Weijian; Wang, Ruihong; Han, Zhi-Long; Han, Jin-Zhong

    2017-12-01

    We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of U(1)_{B-L} extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by the anomaly free condition and the new particles may have exotic B-L charges so that the direct SM Yukawa mass term \\bar{ν }_Lν _R\\overline{φ ^0} and the Majorana mass term (m_N/2)\\overline{ν _R^C}ν _R are naturally forbidden. After the spontaneous breaking of the U(1)_{B-L} symmetry, the discrete Z2 or Z3 symmetry appears as the residual symmetry and gives rise to the stability of intermediate fields as DM candidates. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed.

  6. Measuring neutrino mass without neutrinos!

    CERN Multimedia

    Peach, Kenneth J

    2004-01-01

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

  7. Gauge Trimming of Neutrino Masses

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-01

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

  8. Neutrino mass anarchy

    Science.gov (United States)

    Hall; Murayama; Weiner

    2000-03-20

    What is the form of the neutrino mass matrix which governs the oscillations of the atmospheric and solar neutrinos? Features of the data have led to a dominant viewpoint where the mass matrix has an ordered, regulated pattern, perhaps dictated by a flavor symmetry. We challenge this viewpoint and demonstrate that the data are well accounted for by a neutrino mass matrix which appears to have random entries.

  9. Neutrino Mass Anarchy

    Science.gov (United States)

    Hall, Lawrence; Murayama, Hitoshi; Weiner, Neal

    2000-03-01

    What is the form of the neutrino mass matrix which governs the oscillations of the atmospheric and solar neutrinos? Features of the data have led to a dominant viewpoint where the mass matrix has an ordered, regulated pattern, perhaps dictated by a flavor symmetry. We challenge this viewpoint and demonstrate that the data are well accounted for by a neutrino mass matrix which appears to have random entries.

  10. A Class of Inert N-tuplet Models with Radiative Neutrino Mass and Dark Matter

    OpenAIRE

    Law, Sandy S. C.; McDonald, Kristian L.

    2013-01-01

    We present a class of models with radiative neutrino mass and stable dark-matter candidates. Neutrino mass is generated by a one-loop diagram with the same topography as Ma's 2006 proposal (which used an inert scalar-doublet and singlet fermion). We generalize this approach and determine all variants with new fields no larger than the adjoint representation. When the neutrino mass diagram contains a Majorana mass insertion there are two possibilities, both of which are known. If the mass inse...

  11. Neutrino mass, a status report

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1993-01-01

    Experimental approaches to neutrino mass include kinematic mass measurements, neutrino oscillation searches at rectors and accelerators, solar neutrinos, atmospheric neutrinos, and single and double beta decay. The solar neutrino results yield fairly strong and consistent indications that neutrino oscillations are occurring. Other evidence for new physics is less consistent and convincing

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

    International Nuclear Information System (INIS)

    Chao Wei; Luo Shu; Xing Zhizhong; Zhou Shun

    2008-01-01

    A natural extension of the standard SU(2) L xU(1) 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 L , M D and M R . We show that three light Majorana neutrinos (i.e., the mass eigenstates of ν e , ν μ , and ν τ ) are exactly massless in this model, if and only if M L =M D M R -1 M D T exactly holds. This no-go theorem implies that small but nonvanishing neutrino masses may result from a significant but incomplete cancellation between M L and M D M R -1 M D 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 4 xU(1) 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

  13. Mass and oscillations of Dirac neutrinos

    International Nuclear Information System (INIS)

    Collot, J.

    1989-01-01

    In the most economical extension of the standard model, we have presented the theory of massive Dirac neutrinos. We have particularly emphasized that, in this model, a complete analogy between quarks and leptons can be erected and predicts neutrino flavor oscillations. We have reviewed the last experimental results concerning kinetic neutrino mass experiments and neutrino oscillation investigations

  14. On The Origin of Neutrino Mass and Mixing in the Standard Model

    CERN Document Server

    McElrath, Bob

    2009-01-01

    One can describe cosmological relic neutrinos by adding Lagrange multipliers to the Standard Model Lagrangian for them. The two possible Lagrange multipliers are a chemical potential, which fixes the mean neutrino/anti-neutrino asymmetry, and a Majorana mass, which fixes the mean spin-entropy. Because these neutrinos originated from a thermal bath, their entropy should be maximal, implying that each state in the background is a symmetric superposition of a neutrino and anti-neutrino. Therefore the Standard Model must be augmented by a flavor-diagonal Majorana neutrino mass matrix. This impacts the propagator via tadpole diagrams due to self-interactions. In the low-energy limit, neutrino self-interactions are entirely off-diagonal because same-flavor four-fermion operators vanish by Pauli exclusion. These interactions must be diagonalized when propagating through a bath of neutrinos, using the U(3) global flavor symmetry. U(3) gets broken broken down to SO(3) by Majorana masses, and down to $A_4$ if the three...

  15. Neutrino masses from SUSY breaking in radiative seesaw models

    International Nuclear Information System (INIS)

    Figueiredo, Antonio J.R.

    2015-01-01

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

  16. Neutrino masses and family replication

    International Nuclear Information System (INIS)

    Hung, P.Q.

    1999-01-01

    The issue of whether or not there is any link between the smallness of the neutrino mass (if present) and the odd or even nature of the number of families is investigated. It is found that, by assuming the existence of right-handed neutrinos (which would imply that neutrinos will have a mass) and a new chiral SU(2) gauge theory, a constraint on the nature of the number of families can be obtained. In addition, a model, based on that extra SU(2), is constructed where it is plausible to have one 'very heavy' fourth neutrino and three almost degenerate light neutrinos whose masses are all of the Dirac type. copyright 1999 The American Physical Society

  17. Current Direct Neutrino Mass Experiments

    Directory of Open Access Journals (Sweden)

    G. Drexlin

    2013-01-01

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

  18. Neutrino masses and family symmetry

    International Nuclear Information System (INIS)

    Grinstein, B.; Preskill, J.; Wise, M.B.

    1985-01-01

    Neutrino masses in the 100 eV-1 MeV range are permitted if there is a spontaneously broken global family symmetry that allows the heavy neutrinos to decay by Goldstone boson emission with a cosmologically acceptable lifetime. The family symmetry may be either abelian or nonabelian; we present models illustrating both possibilities. If the family symmetry is nonabelian, then the decay tau -> μ + Goldstone boson or tau -> e + Goldstone may have an observable rate. (orig.)

  19. Direct measurements of neutrino mass

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1991-01-01

    Some recent developments in the experimental search for neutrino mass are discussed. New data from Los Alamos on the electron neutrino mass as measured in tritium beta decay give an upper limit of 9.3 eV at the 95% confidence level. This result is not consistent with the long-standing ITEP result of 26(5) eV within a ''model-independent'' range of 17 to 40 eV. It now appears that the electron neutrino is not sufficiently massive to close the universe by itself. Hime and Jelley report finding new evidence for a 17-keV neutrino in the Β decay of 35 S and 63 Ni. Many other experiments are being reported and the situation is still unresolved. 56 refs., 1 fig., 3 tabs

  20. A model of neutrino mass and dark matter with an accidental symmetry

    Directory of Open Access Journals (Sweden)

    Amine Ahriche

    2015-06-01

    Full Text Available We present a model of radiative neutrino mass that automatically contains an accidental Z2 symmetry and thus provides a stable dark matter candidate. This allows a common framework for the origin of neutrino mass and dark matter without invoking any symmetries beyond those of the Standard Model. The model can be probed by direct-detection experiments and μ→e+γ searches, and predicts a charged scalar that can appear at the TeV scale, within reach of collider experiments.

  1. Neutrino mass, leptogenesis and FIMP dark matter in a U(1){sub B-L} model

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Anirban; Khan, Sarif [Harish-Chandra Research Institute, Allahabad (India); Homi Bhabha National Institute, Training School Complex, Mumbai (India); Choubey, Sandhya [Harish-Chandra Research Institute, Allahabad (India); Homi Bhabha National Institute, Training School Complex, Mumbai (India); AlbaNova University Center, Department of Theoretical Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm (Sweden)

    2017-12-15

    The Standard Model (SM) is inadequate to explain the origin of tiny neutrino masses, the dark matter (DM) relic abundance and the baryon asymmetry of the Universe. In this work, to address all three puzzles, we extend the SM by a local U(1){sub B-L} gauge symmetry, three right-handed (RH) neutrinos for the cancellation of gauge anomalies and two complex scalars having non-zero U(1){sub B-L} charges. All the newly added particles become massive after the breaking of the U(1){sub B-L} symmetry by the vacuum expectation value (VEV) of one of the scalar fields φ{sub H}. The other scalar field, φ{sub DM}, which does not have any VEV, becomes automatically stable and can be a viable DM candidate. Neutrino masses are generated using the Type-I seesaw mechanism, while the required lepton asymmetry to reproduce the observed baryon asymmetry can be attained from the CP violating out of equilibrium decays of the RH neutrinos in TeV scale. More importantly within this framework, we study in detail the production of DM via the freeze-in mechanism considering all possible annihilation and decay processes. Finally, we find a situation when DM is dominantly produced from the annihilation of the RH neutrinos, which are at the same time also responsible for neutrino mass generation and leptogenesis. (orig.)

  2. Neutrino mass, leptogenesis and FIMP dark matter in a U(1)_{B-L} model

    Science.gov (United States)

    Biswas, Anirban; Choubey, Sandhya; Khan, Sarif

    2017-12-01

    The Standard Model (SM) is inadequate to explain the origin of tiny neutrino masses, the dark matter (DM) relic abundance and the baryon asymmetry of the Universe. In this work, to address all three puzzles, we extend the SM by a local U(1)_{B-L} gauge symmetry, three right-handed (RH) neutrinos for the cancellation of gauge anomalies and two complex scalars having non-zero U(1)_{B-L} charges. All the newly added particles become massive after the breaking of the U(1)_{B-L} symmetry by the vacuum expectation value (VEV) of one of the scalar fields φ _H. The other scalar field, φ _DM, which does not have any VEV, becomes automatically stable and can be a viable DM candidate. Neutrino masses are generated using the Type-I seesaw mechanism, while the required lepton asymmetry to reproduce the observed baryon asymmetry can be attained from the CP violating out of equilibrium decays of the RH neutrinos in TeV scale. More importantly within this framework, we study in detail the production of DM via the freeze-in mechanism considering all possible annihilation and decay processes. Finally, we find a situation when DM is dominantly produced from the annihilation of the RH neutrinos, which are at the same time also responsible for neutrino mass generation and leptogenesis.

  3. Challenging Lorentz noninvariant neutrino oscillations without neutrino masses

    OpenAIRE

    Barger, V.; Marfatia, D.; Whisnant, K.

    2007-01-01

    We show that the combined data from solar, long-baseline and reactor neutrino experiments can exclude the generalized bicycle model of Lorentz noninvariant direction-dependent and/or direction-independent oscillations of massless neutrinos. This model has five parameters, which is more than is needed in standard oscillation phenomenology with neutrino masses. Solar data alone are sufficient to exclude the pure direction-dependent case. The combination of solar and long-baseline data rules out...

  4. AN OVERVIEW OF NEUTRINO MASSES AND MIXING IN SO(10) MODELS.

    Energy Technology Data Exchange (ETDEWEB)

    CHEN,M.C.MAHANTHAPPA,K.T.

    2003-06-05

    We review in this talk various SUSY SO(10) models. Specifically, we discuss how small neutrino masses are generated in and generic predictions of different SO(10) models. A comparison of the predictions of these models for sin{sup 2} {theta}{sub 13}is given.

  5. Massive Neutrinos and the Higgs Mass Window

    CERN Document Server

    Casas, J A; Ibarra, Alejandro; Quirós, Mariano

    2000-01-01

    If neutrino masses are produced by a see-saw mechanism the Standard Model prediction for the Higgs mass window (defined by upper (perturbativity) and lower (stability) bounds) can be substantially affected. Actually the Higgs mass window can close completely, which settles an upper bound on the Majorana mass for the right-handed neutrinos, $M$, ranging from $10^{13}$ GeV for three generations of quasi-degenerate massive neutrinos with $m_\

  6. A class of inert N-tuplet models with radiative neutrino mass and dark matter

    Science.gov (United States)

    Law, Sandy S. C.; McDonald, Kristian L.

    2013-09-01

    We present a class of models with radiative neutrino mass and stable dark-matter candidates. Neutrino mass is generated by a one-loop diagram with the same topography as Ma's 2006 proposal (which used an inert scalar-doublet and singlet fermion). We generalize this approach and determine all variants with new fields no larger than the adjoint representation. When the neutrino mass diagram contains a Majorana mass insertion there are two possibilities, both of which are known. If the mass insertion is of the Dirac type there are seven additional models, two of which are excluded by direct-detection experiments. The other five models are also constrained, such that only scalar dark-matter is viable. There are cases with an inert singlet, an inert doublet, and an inert triplet, providing a natural setting for inert N -tuplet models of dark matter, with the additional feature of achieving radiative neutrino mass. We show that some of the models admit a simple explanation for the (requisite) discrete symmetry, and briefly discuss cases with representations larger than the adjoint, which can admit a connection to the astrophysical gamma-ray signal.

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

    Indian Academy of Sciences (India)

    An attempt has been made to discriminate theoretically the three possible patterns of neutrino mass models,viz., degenerate, inverted hierarchical and normal hierachical models, within the framework of Type-II see-saw formula. From detailed numerical analysis we are able to arrive at a conclusion that the inverted ...

  8. Lepton flavour violation, Yukawa unification and neutrino masses in supersymmetric unified models

    International Nuclear Information System (INIS)

    Oliveira, J.M.D.S.B.

    2000-12-01

    We explore some phenomenological consequences of models based on supersymmetric extensions of the Standard Model. In particular, we focus on the Minimal Supersymmetric Standard Model supplemented by right-handed neutrinos in the context of the Pati-Salam SU(4) x SU(2) L x SU(2) R Grand Unified Theory. We start by analysing the possibility of using Lepton Flavour Violation as a probe of physics beyond the Standard Model. We show that the μ → eγ and τ → μγ decays impose important constraints to the soft supersymmetry breaking parameters of the Pati-Salam model that already allow the formulation of lower bounds for the masses of the lighter supersymmetric particles. Secondly, we investigate how third family Yukawa unification can be used to provide a window into the soft supersymmetry breaking Lagrangian. We show that, a successful top quark mass prediction requires that the supersymmetric corrections to the bottom quark mass are small which, in turn, imposes a distinct hierarchy between the soft breaking parameters. Finally, we explicitly construct a realistic model of quark, charged lepton and neutrino masses and mixing angles, based on the Pati-Salam. gauge group supplemented by an abelian flavour symmetry, that can explain the large atmospheric neutrino mixing angle, suggested by the Super-Kamiokande data, and account for the large mixing angle Mikheyev-Smirnov-Wolfenstein solution to the solar neutrino problem. (author)

  9. Does a massive neutrino imply to go beyond the standard model?; la masse du neutrino ouvre-t-elle une porte au-dela du modele standard?

    Energy Technology Data Exchange (ETDEWEB)

    Le Diberder, F.; Cohen-Tannoudji, G.; Davier, M. [and others

    2002-01-01

    This article gathers the 15 contributions to this seminar. The purpose of this seminar was to define up to which extend the standard model is challenged by massive neutrinos. A non-zero mass for neutrinos, even a few eV, would solve the problem of the missing mass of the universe, and it would mean no more need for supersymmetry and its neutralinos. A massless neutrino theoretically implies a symmetry and an interaction that are not described by the standard model. In some aspects, it appears that a non-zero mass is natural within the framework of the standard model, and for some scientists the smallness of this value could be the hint of the need for a new physics.

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

    Science.gov (United States)

    Borgohain, Happy; Das, Mrinal Kumar

    2017-09-01

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

  11. Starobinsky-Like Inflation and Neutrino Masses in a No-Scale SO(10) Model

    CERN Document Server

    Ellis, John

    2016-11-08

    Using a no-scale supergravity framework, we construct an SO(10) model that makes predictions for cosmic microwave background observables similar to those of the Starobinsky model of inflation, and incorporates a double-seesaw model for neutrino masses consistent with oscillation experiments and late-time cosmology. We pay particular attention to the behaviour of the scalar fields during inflation and the subsequent reheating.

  12. Systems of neutrinos with mass

    International Nuclear Information System (INIS)

    Groot, S.R. de

    1984-01-01

    From the formalism of relativistic kinetic theory and the weak interaction Lagrangian the volume viscosity of a massive neutrino system is derived. Its value is calculated as a function of the neutrino mass and the temperature. Its role in the way of expanding or contraction of neutrino clouds in the universe is discussed. (Author) [pt

  13. Laboratory Limits on Neutrino Masses

    Science.gov (United States)

    Weinheimer, Christian

    The recent neutrino oscillation experiments have obtained nonzero differences of squared neutrino masses and therefore proven that neutrinos are massive particles. The values of the neutrino masses have to be determined in a different way. There are two classes of laboratory experiments, both of which have yielded up to now only upper limits on neutrino masses. The direct mass experiments investigate the kinematics of weak decays, obtaining information about the neutrino mass without further requirements. Here, the tritium β decay experiments give the most stringent results. The search for neutrinoless double β decay is also very sensitive to the neutrino mass states. However, this search is complementary to direct neutrino mass experiments, since it requires neutrinos to be identical to their antiparticles and probes a linear combination of neutrino masses including complex phases. This chapter is structured as follows. After an introduction in Sect. 2.1, the two approaches are discussed together with the current experimental results in Sects. 2.2 and 2.3, followed by consideration of the outlook for future activities in Sect. 2.4.

  14. New scotogenic model of neutrino mass with U(1){sub D} gauge interaction

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Picek, Ivica; Radovčić, Branimir [Department of Physics, Faculty of Science, University of Zagreb, P.O.B. 331, HR-10002 Zagreb (Croatia)

    2013-11-04

    We propose a new realization of the one-loop radiative model of neutrino mass generated by dark matter (scotogenic), where the particles in the loop have an additional U(1){sub D} gauge symmetry, which may be exact or broken to Z{sub 2}. This model is relevant to a number of astrophysical observations, including AMS-02 and the dark-matter distribution in dwarf galactic halos.

  15. Flavor connections and neutrino mass hierarchy in variant invisible axion models without domain wall problem

    International Nuclear Information System (INIS)

    Geng, C.Q.; Ng, J.N.

    1988-08-01

    New types of invisible axion model based on the recent variant axion models are presented. They belong to the N=1 type model and hence are free of domain wall problems. The Peccei-Quinn symmetry transformations are not totally generation and flavor blind, which may help in understanding the small values of electron and u-quark and large t-quark masses. The light neutrino mass pattern in the two Higgs singlet models can have a very different hierarchy that differs from the other type invisible axion model. (Author) (25 refs.)

  16. Neutrinos and Physics Beyond Electroweak and Cosmological Standard Models

    CERN Document Server

    Kirilova, Daniela

    2014-01-01

    This is a short review of the established and the proposed by physics beyond Standard Electroweak Model and beyond Standard Cosmological Model neutrino characteristics. In particular, cosmological effects of and cosmological constraints on: extra neutrino families, neutrino mass differences and mixing, lepton asymmetry in the neutrino sector, neutrino masses, light sterile neutrino, are discussed.

  17. The Masses of the Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Peter S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-05-10

    If the cosmological limits on the sum of the neutrino masses are taken seriously we have first measurements of the masses of the neutrinos. Using the Planck experiment's limit $\\sum_{i=1}^3{m_i} < 230 ~meV$ and some simple assumptions on measurement uncertainties the mass of the heaviest neutrino is $63\\pm11 ~meV$ and the lightest $40\\pm18 ~meV$ for either hierarchy.

  18. Lepton flavor violation and scalar dark matter in a radiative model of neutrino masses

    Science.gov (United States)

    Esch, Sonja; Klasen, Michael; Lamprea, David R.; Yaguna, Carlos E.

    2018-02-01

    We consider a simple extension of the Standard Model that can account for the dark matter and explain the existence of neutrino masses. The model includes a vector-like doublet of SU(2), a singlet fermion, and two scalar singlets, all of them odd under a new Z_2 symmetry. Neutrino masses are generated radiatively by one-loop processes involving the new fields, while the dark matter candidate is the lightest neutral particle among them. We focus specifically on the case where the dark matter particle is one of the scalars and its relic density is determined by its Yukawa interactions. The phenomenology of this setup, including neutrino masses, dark matter and lepton flavor violation, is analyzed in some detail. We find that the dark matter mass must be below 600 GeV to satisfy the relic density constraint. Lepton flavor violating processes are shown to provide the most promising way to test this scenario. Future μ → 3e and μ - e conversion experiments, in particular, have the potential to probe the entire viable parameter space of this model.

  19. Constraints on a massive Dirac neutrino model

    International Nuclear Information System (INIS)

    Wynter, T.; Randall, L.

    1994-01-01

    We examine constraints on a simple neutrino model in which there are three massless and three massive Dirac neutrinos and in which the left-handed neutrinos are linear combinations of doublet and singlet neutrinos. We examine constraints from direct decays into heavy neutrinos, indirect effects on electroweak parameters, and flavor-changing processes. We combine these constraints to examine the allowed mass range for the heavy neutrinos of each of the three generations

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

    Indian Academy of Sciences (India)

    Thus we have the bound for the natural selection: mI. LL > vLf. (4). Denoting the heaviest right-handed neutrino mass as vR and taking MW ∼ 82. GeV [22] in the expression of vL, the following lower bounds on vR for the natural selection are obtained: For normal hierarchical and inverted hierarchical model: vR > γ1.345 ...

  1. New class of two-loop neutrino mass models with distinguishable phenomenology

    Science.gov (United States)

    Cao, Qing-Hong; Chen, Shao-Long; Ma, Ernest; Yan, Bin; Zhang, Dong-Ming

    2018-04-01

    We discuss a new class of neutrino mass models generated in two loops, and explore specifically three new physics scenarios: (A) doubly charged scalar, (B) dark matter, and (C) leptoquark and diquark, which are verifiable at the 14 TeV LHC Run-II. We point out how the different Higgs insertions will distinguish our two-loop topology with others if the new particles in the loop are in the simplest representations of the SM gauge group.

  2. Renormalization of seesaw neutrino masses in the standard model ...

    Indian Academy of Sciences (India)

    experimental constraints on electroweak mixing angle and proton lifetime. But predictions from SO(10) GUT are ... One method consists of running the gauge couplings and using the matching ..... where the running masses of top and bottom quarks are obtained from the respective pole masses СФУР. ШУФ = 175 6 GeV ...

  3. A novel scenario for neutrino masses in superstring-inspired GUT models

    International Nuclear Information System (INIS)

    Ranfone, S.; Papageorgiu, E.

    1992-06-01

    It is shown that the usual ''super-suppression'' of the standard neutrino masses in the context of the SU(4) x O(4) and the flipped SU(5) x U(1) models may be avoided in the presence of large vacuum expectation values (VEV's) of order M GUT for the right-handed sneutrinos, which have been introduced as a means to improve the mass relations between the down-type quarks and the charged leptons in the first of the two models. (author)

  4. Explaining dark matter and neutrino mass in the light of TYPE-II seesaw model

    Science.gov (United States)

    Biswas, Anirban; Shaw, Avirup

    2018-02-01

    With the motivation of simultaneously explaining dark matter and neutrino masses, mixing angles, we have invoked the Type-II seesaw model extended by an extra SU(2) doublet Φ. Moreover, we have imposed a Z2 parity on Φ which remains unbroken as the vacuum expectation value of Φ is zero. Consequently, the lightest neutral component of Φ becomes naturally stable and can be a viable dark matter candidate. On the other hand, light Majorana masses for neutrinos have been generated following usual Type-II seesaw mechanism. Further in this framework, for the first time we have derived the full set of vacuum stability and unitarity conditions, which must be satisfied to obtain a stable vacuum as well as to preserve the unitarity of the model respectively. Thereafter, we have performed extensive phenomenological studies of both dark matter and neutrino sectors considering all possible theoretical and current experimental constraints. Finally, we have also discussed a qualitative collider signatures of dark matter and associated odd particles at the 13 TeV Large Hadron Collider.

  5. Neutrino masses and superheavy dark matter in the 3-3-1-1 model

    International Nuclear Information System (INIS)

    Huong, D.T.; Dong, P.V.

    2017-01-01

    In this work, we interpret the 3-3-1-1 model when the B - L and 3-3-1 breaking scales behave simultaneously as the inflation scale. This setup not only realizes the previously achieved consequences of inflation and leptogenesis, but also provides new insights in superheavy dark matter and neutrino masses. We argue that the 3-3-1-1 model can incorporate a scalar sextet, which induces both small masses for the neutrinos via a combined type I and II seesaw and large masses for the new neutral fermions. Additionally, all the new particles have large masses in the inflation scale. The lightest particle among the W-particles that have abnormal (i.e., wrong) B - L number in comparison to those of the standard model particles may be superheavy dark matter as it is stabilized by W-parity. The dark matter candidate may be a Majorana fermion, a neutral scalar, or a neutral gauge boson, which was properly created in the early universe due to gravitational effects on the vacuum or thermal production after cosmic inflation. (orig.)

  6. Supernova signatures of neutrino mass ordering

    Science.gov (United States)

    Scholberg, Kate

    2018-01-01

    A suite of detectors around the world is poised to measure the flavor-energy-time evolution of the ten-second burst of neutrinos from a core-collapse supernova occurring in the Milky Way or nearby. Next-generation detectors to be built in the next decade will have enhanced flavor sensitivity and statistics. Not only will the observation of this burst allow us to peer inside the dense matter of the extreme event and learn about the collapse processes and the birth of the remnant, but the neutrinos will bring information about neutrino properties themselves. This review surveys some of the physical signatures that the currently-unknown neutrino mass pattern will imprint on the observed neutrino events at Earth, emphasizing the most robust and least model-dependent signatures of mass ordering.

  7. Neutrinos from the Early Universe and physics beyond standard models

    Directory of Open Access Journals (Sweden)

    Kirilova Daniela

    2015-01-01

    Full Text Available Neutrino oscillations present the only robust example of experimentally detected physics beyond the standard model. This review discusses the established and several hypothetical beyond standard models neutrino characteristics and their cosmological effects and constraints. Particularly, the contemporary cosmological constraints on the number of neutrino families, neutrino mass differences and mixing, lepton asymmetry in the neutrino sector, neutrino masses, light sterile neutrino are briefly reviewed.

  8. Leptogenesis. Theory and neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.

    2012-12-15

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

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

    Directory of Open Access Journals (Sweden)

    Zhen Liu

    2017-02-01

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

  10. Neutrinos

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    The Standard Model predicts that the neutrinos are massless and do not mix. Generic extensions of the Standard Model predict that neutrinos are massive (but, very likely, much lighter than the charged fermions). Therefore, the search for neutrino masses and mixing tests the Standard Model and probes new phasics. Measurements of various features of the fluxes of atmospheric, solar and, more recently, reactor neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. These results have significant theoretical implications: new physics exists, and its scale can be estimated. There are interesting lessons for grand unified theories and for models of extra dimensions. The measured neutrino flavor parameters pose a challenge to flavor models.

  11. Symplectic symmetry of the neutrino mass for many neutrino flavors

    International Nuclear Information System (INIS)

    Oeztuerk, N.; Ankara Univ.

    2001-01-01

    The algebraic structure of the neutrino mass Hamiltonian is presented for two neutrino flavors considering both Dirac and Majorana mass terms. It is shown that the algebra is Sp(8) and also discussed how the algebraic structure generalizes for the case of more than two neutrino flavors. (orig.)

  12. Seesaw neutrino masses and mixing with extended democracy

    Energy Technology Data Exchange (ETDEWEB)

    Joaquim, F.R

    2001-05-01

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

  13. Evaluation of the Majorana phases of a general Majorana neutrino mass matrix: Testability of hierarchical flavour models

    Directory of Open Access Journals (Sweden)

    Rome Samanta

    2016-03-01

    Full Text Available We evaluate the Majorana phases for a general 3×3 complex symmetric neutrino mass matrix on the basis of Mohapatra–Rodejohann's phase convention using the three rephasing invariant quantities I12, I13 and I23 proposed by Sarkar and Singh. We find them interesting as they allow us to evaluate each Majorana phase in a model independent way even if one eigenvalue is zero. Utilizing the solution of a general complex symmetric mass matrix for eigenvalues and mixing angles we determine the Majorana phases for both the hierarchies, normal and inverted, taking into account the constraints from neutrino oscillation global fit data as well as bound on the sum of the three light neutrino masses (Σimi and the neutrinoless double beta decay (ββ0ν parameter |m11|. This methodology of finding the Majorana phases is applied thereafter in some predictive models for both the hierarchical cases (normal and inverted to evaluate the corresponding Majorana phases and it is shown that all the sub cases presented in inverted hierarchy section can be realized in a model with texture zeros and scaling ansatz within the framework of inverse seesaw although one of the sub cases following the normal hierarchy is yet to be established. Except the case of quasi degenerate neutrinos, the methodology obtained in this work is able to evaluate the corresponding Majorana phases, given any model of neutrino masses.

  14. The Mainz Neutrino Mass Experiment

    Czech Academy of Sciences Publication Activity Database

    Kraus, C.; Bornschein, L.; Bonn, J.; Bornschein, B.; Flatt, B.; Kovalík, Alojz; Müller, B.; Otten, EW; Schall, JP.; Thummler, T.; Weinheimer, C.

    2005-01-01

    Roč. 143, - (2005), s. 143 ISSN 0920-5632. [International Conference on Neutrino Physics and Astrophysics /21./. Paříž, 14.06.2004-19.06.2004] R&D Projects: GA MŠk 1P04LA213 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutrino mass * tritium beta decay Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.875, year: 2005

  15. Status of neutrino mass experiments

    International Nuclear Information System (INIS)

    Fackler, O.

    1985-12-01

    In 1980 two experiments ignited a fertile field of research the determination of the neutrino masses. Subsequently, over 35 experiments using a variety of techniques have probed or are probing this question. Primarily I will discuss electron antineutrino (hereafter referred to as neutrino) mass experiments. However, let me begin in Section I to discuss astronomical and terrestrial observations which motivated these experiments. In Section II, I will quote limits from muon and tau mass determinations. These limits are more thoroughly discussed in other papers. I will continue by describing the four approaches used to measure the electron neutrino mass. In Section III, tritium beta decay mass determinations will be reviewed. This section includes a general summary of previous experimental results, and discussion of the major ongoing experiments. Section IV offers concluding remarks. 24 refs., 24 figs

  16. Status of neutrino mass experiments

    International Nuclear Information System (INIS)

    Fackler, O.

    1985-01-01

    In 1980 two experiments ignited a fertile field of research - the determination of the neutrino masses. Subsequently, over 35 experiments using a variety of techniques have probed or are probing this question. Primarily the author discuss electron antineutrino (hereafter referred to as neutrino) mass experiments. Section I begins with a discussion of astronomical and terrestrial observations which motivated these experiments. In Section II, the author quote limits from muon and tau mass determinations. These limits are more thoroughly discussed in other paper. The author continues by describing the four approaches used to measure the electron neutrino mass. In Section III, tritium beta decay mass determinations are reviewed. This section includes a general summary of previous experimental results, and discussion of the major ongoing experiments. Section IV offers concluding remarks

  17. Radiative neutrino masses from order-4 CP symmetry

    Science.gov (United States)

    Ivanov, Igor P.

    2018-02-01

    Generalized CP symmetry of order 4 (CP4) is surprisingly powerful in shaping scalar and quark sectors of multi-Higgs models. Here, we extend this framework to the neutrino sector. We build two simple Majorana neutrino mass models with unbroken CP4, which are analogous to Ma's scotogenic model. Both models use three Higgs doublets and two or three right-handed (RH) neutrinos. The minimal CP4 symmetric scotogenic model uses only two RH neutrinos, leads to three non-zero light neutrino masses, and contains a built-in mechanism to further suppress them via phase alignment. With three RH neutrinos, one generates a type I seesaw mass matrix of rank 1, which is then corrected by the same scotogenic mechanism, naturally leading to two neutrino mass scales with mild hierarchy. These minimal CP4-based constructions emerge as a primer for introducing additional symmetry structures and exploring their phenomenological consequences.

  18. Constraining dynamical neutrino mass generation with cosmological data

    Energy Technology Data Exchange (ETDEWEB)

    Koksbang, S.M.; Hannestad, S., E-mail: koksbang@phys.au.dk, E-mail: sth@phys.au.dk [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

    2017-09-01

    We study models in which neutrino masses are generated dynamically at cosmologically late times. Our study is purely phenomenological and parameterized in terms of three effective parameters characterizing the redshift of mass generation, the width of the transition region, and the present day neutrino mass. We also study the possibility that neutrinos become strongly self-interacting at the time where the mass is generated. We find that in a number of cases, models with large present day neutrino masses are allowed by current CMB, BAO and supernova data. The increase in the allowed mass range makes it possible that a non-zero neutrino mass could be measured in direct detection experiments such as KATRIN. Intriguingly we also find that there are allowed models in which neutrinos become strongly self-interacting around the epoch of recombination.

  19. On the muon neutrino mass

    Energy Technology Data Exchange (ETDEWEB)

    Angelov, N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Balestra, F. [Dipartimento di Fisica Generale ' Amedeo Avogadro' , University of Torino, INFN, Sez. di Torino, Turin (Italy); Batusov, Yu. [Joint Institute for Nuclear Research, Dubna (Russian Federation)] (and others)

    2006-12-11

    During the runs of the PS 179 experiment at LEAR of CERN, we photographed an event of antiproton-Ne absorption, with a complete {pi}{sup +}->{mu}{sup +}->e{sup +} chain. From the vertex of the reaction a very slow energy {pi}{sup +} was emitted. The {pi}{sup +} decays into a {mu}{sup +} and subsequently the {mu}{sup +} decays into a positron. At the first decay vertex a muon neutrino was emitted and at the second decay vertex an electron neutrino and a muon antineutrino. Measuring the pion and muon tracks and applying the momentum and energy conservation and using a classical statistical interval estimator, we obtained an experimental upper limit for the muon neutrino mass: m{sub {nu}}<2.2 MeV at a 90% confidence level. A statistical analysis has been performed of the factors contributing to the square value of the neutrino mass, to deduce the possibility to reach experimentally the lowest muon neutrino mass limit from the {pi}->{mu}{nu} decays.

  20. Neutrino masses and mixing in supersymmetric theories

    Indian Academy of Sciences (India)

    parity violation provide a natural framework where small neutrino masses can be generated. We discuss neutrino masses and mixing in these theories in the presence of trilinear lepton number violating couplings. It will be shown that ...

  1. Can Neutrinos be Degenerate in Mass?

    CERN Document Server

    Ellis, Jonathan Richard; Ellis, John; Lola, Smaragda

    1999-01-01

    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 tanbe...

  2. Neutrino mass as the probe of intermediate mass scales

    Energy Technology Data Exchange (ETDEWEB)

    Senjanovic, G.

    1980-01-01

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

  3. Absolute values of neutrino masses: status and prospects

    International Nuclear Information System (INIS)

    Bilenky, S.M.; Giunti, C.; Grifols, J.A.; Masso, E.

    2003-01-01

    Compelling evidences in favor of neutrino masses and mixing obtained in the last years in Super-Kamiokande, SNO, KamLAND and other neutrino experiments made the physics of massive and mixed neutrinos a frontier field of research in particle physics and astrophysics. There are many open problems in this new field. In this review we consider the problem of the absolute values of neutrino masses, which apparently is the most difficult one from the experimental point of view. We discuss the present limits and the future prospects of β-decay neutrino mass measurements and neutrinoless double-β decay. We consider the important problem of the calculation of nuclear matrix elements of neutrinoless double-β decay and discuss the possibility to check the results of different model calculations of the nuclear matrix elements through their comparison with the experimental data. We discuss the upper bound of the total mass of neutrinos that was obtained recently from the data of the 2dF Galaxy Redshift Survey and other cosmological data and we discuss future prospects of the cosmological measurements of the total mass of neutrinos. We discuss also the possibility to obtain information on neutrino masses from the observation of the ultra high-energy cosmic rays (beyond the GZK cutoff). Finally, we review the main aspects of the physics of core-collapse supernovae, the limits on the absolute values of neutrino masses from the observation of SN1987A neutrinos and the future prospects of supernova neutrino detection

  4. Common origin of RK and neutrino masses

    Science.gov (United States)

    Päs, H.; Schumacher, E.

    2015-12-01

    The same leptoquarks that explain the recently observed anomaly in RK can generate naturally small Majorana neutrino masses at one-loop level through mixing with the standard model Higgs. This is particularly relevant in models with at least two leptoquarks contributing to b →s l l transitions.

  5. Understanding neutrino masses and mixings

    Indian Academy of Sciences (India)

    that all the above data can be understood in terms of oscillations of the three known neutrinos, i.e., among themselves. since the ... are expressed in terms of the mass eigenstates. ( = 1 2 3) as follows: « = И ... down by one order of magnitude. 1.1.4 Н 3. The reactor experiments CHOOZ and PALO VERDE imply that Н 3 ≤.

  6. Direct measurements of neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  7. Neutrinos: in and out of the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Parke, Stephen; /Fermilab

    2006-07-01

    The particle physics Standard Model has been tremendously successful in predicting the outcome of a large number of experiments. In this model Neutrinos are massless. Yet recent evidence points to the fact that neutrinos are massive particles with tiny masses compared to the other particles in the Standard Model. These tiny masses allow the neutrinos to change flavor and oscillate. In this series of Lectures, I will review the properties of Neutrinos In the Standard Model and then discuss the physics of Neutrinos Beyond the Standard Model. Topics to be covered include Neutrino Flavor Transformations and Oscillations, Majorana versus Dirac Neutrino Masses, the Seesaw Mechanism and Leptogenesis.

  8. Neutrino masses, mixings, and FCNC’s in an S3 flavor symmetric extension of the standard model

    International Nuclear Information System (INIS)

    Mondragón, A.; Mondragón, M.; Peinado, E.

    2011-01-01

    By introducing threeHiggs fields that are SU(2) doublets and a flavor permutational symmetry, S 3 , in the theory, we extend the concepts of flavor and generations to the Higgs sector and formulate a Minimal S 3 -Invariant Extension of the Standard Model. The mass matrices of the neutrinos and charged leptons are re-parameterized in terms of their eigenvalues, then the neutrino mixing matrix, V PMNS , is computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained in excellent agreement with the latest experimental data. We also compute the branching ratios of some selected flavor-changing neutral current (FCNC) processes, as well as the contribution of the exchange of neutral flavor-changing scalars to the anomaly of the magnetic moment of the muon, as functions of the masses of charged leptons and the neutral Higgs bosons. We find that the S 3 × Z 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 bounds by many orders of magnitude. The contribution of FCNC’s to the anomaly of the muon’s magnetic moment is small, but not negligible.

  9. Beyond the Standard Model: The Weak Scale, Neutrino Mass, and the Dark Sector

    International Nuclear Information System (INIS)

    Weiner, Neal

    2010-01-01

    The goal of this proposal was to advance theoretical studies into questions of collider physics at the weak scale, models and signals of dark matter, and connections between neutrino mass and dark energy. The project was a significant success, with a number of developments well beyond what could have been anticipated at the outset. A total of 35 published papers and preprints were produced, with new ideas and signals for LHC physics and dark matter experiments, in particular. A number of new ideas have been found on the possible indirect signals of models of dark matter which relate to the INTEGRAL signal of astrophysical positron production, high energy positrons seen at PAMELA and Fermi, studies into anomalous gamma rays at Fermi, collider signatures of sneutrino dark matter, scenarios of Higgs physics arising in SUSY models, the implications of galaxy cluster surveys for photon-axion conversion models, previously unconsidered collider phenomenology in the form of 'lepton jets' and a very significant result for flavor physics in supersymmetric theories. Progress continues on all fronts, including development of models with dramatic implications for direct dark matter searches, dynamics of dark matter with various excited states, flavor physics, and consequences of modified missing energy signals for collider searches at the LHC.

  10. Radiative left-right Dirac neutrino mass

    Science.gov (United States)

    Ma, Ernest; Sarkar, Utpal

    2018-01-01

    We consider the conventional left-right gauge extension of the standard model of quarks and leptons without a scalar bidoublet. We study systematically how one-loop radiative Dirac neutrino masses may be obtained. In addition to two well-known cases from almost 30 years ago, we find two new scenarios with verifiable predictions.

  11. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    In this article I review the constraints on neutrino mass and mixing coming from type-II supernovae. The bounds obtained on these parameters from shock reheating, -process nucleosynthesis and from SN1987A are discussed. Given the current constraints on neutrino mass and mixing the effect of oscillations of neutrinos ...

  12. Neutrino Masses from Neutral Top Partners

    CERN Document Server

    Batell, Brian

    2015-01-01

    We present theories of `Natural Neutrinos' in which neutral fermionic top partner fields are simultaneously the right-handed neutrinos (RHN), linking seemingly disparate aspects of the Standard Model structure: a) The RHN top partners are responsible for the observed small neutrino masses, b) They help ameliorate the tuning in the weak scale and address the little hierarchy problem, and c) The factor of $3$ arising from $N_c$ in the top-loop Higgs mass corrections is countered by a factor $3$ from the number of vector-like generations of RHN. The RHN top partners may arise in pseudo-Nambu-Goldstone-Boson (pNGB) Higgs models such as the Twin Higgs, as well as more general Composite, Little, and Orbifold Higgs scenarios, and three simple example models are presented. This framework firmly predicts a TeV-scale seesaw, as the RHN masses are bounded to be below the TeV scale by naturalness. The generation of light neutrino masses relies on a collective breaking of lepton number, allowing for comparatively large ne...

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

    Indian Academy of Sciences (India)

    the sum of the two terms and 'pure Type-II see-saw formula' to represent only the first term. Type-II ... the vacuum expectation value (VEV) of the Higgs fields imparting mass to the right-handed neutrinos and fR is the Yukawa coupling matrix. The second term. mII. LL in eq. .... We thus express MRR in the most general form ...

  14. Neutrino masses in astrophysics and cosmology

    International Nuclear Information System (INIS)

    Raffelt, G.G.

    1996-01-01

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

  15. Neutrino masses in astrophysics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  16. Neutrino mass constraints from joint cosmological probes.

    Science.gov (United States)

    Kwan, Juliana

    2018-01-01

    One of the most promising avenues to come from precision cosmology is the measurement of the sum of neutrino masses in the next 5-10 years. Ongoing imaging surveys, such as the Dark Energy Survey and the Hyper Suprime Cam survey, will cover a substantial volume of the sky and when combined with existing spectroscopic data, are expected to deliver a definitive measurement in the near future. But it is important that the accuracy of theoretical predictions matches the precision of the observational data so that the neutrino mass signal can be properly detected without systematic error. To this end, we have run a suite of high precision, large volume cosmological N-body simulations containing massive neutrinos to quantify their effect on probes of large scale structure such as weak lensing and galaxy clustering. In this talk, I will describe the analytical tools that we have developed to extract the neutrino mass that are capable of fully utilizing the non-linear regime of structure formation. These include predictions for the bias in the clustering of dark matter halos (one of the fundamental ingredients of the halo model) with an error of only a few percent.

  17. Neutrino Masses and Lepton-Flavor Violation in Supersymmetric Models with lopsided Froggatt-Nielsen charges

    CERN Document Server

    Sato, J; Sato, Joe; Tobe, Kazuhiro

    2001-01-01

    We analyze in detail lepton-flavor violation (LFV) in the charged-lepton sector such as $\\mu \\to e \\gamma$, $\\tau \\to \\mu \\gamma$, $\\mu \\to eee$ and the $\\mu \\to e$ conversion in nuclei, within the framework of supersymmetric models with lopsided Froggatt--Nielsen charges, in which the large mixing in the neutrino sector as well as small mixings in the quark sector can be naturally accommodated. We show that the present experimental limits on the LFV processes already exclude some of the models. The future proposed search for LFV, especially in muon processes, can provide a significant probe to this framework. We also stress the importance of the measurement of $U^{MNS}_{e3}$ in neutrino experiments, and the fact that the KamLAND experiment could play a significant role to test a certain class of models.

  18. Neutrino Masses and Oscillations

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Treille, Daniel

    2002-01-01

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

  19. Electron capture and the neutrino mass

    Science.gov (United States)

    Faessler, Amand

    2018-02-01

    The electron neutrino mass can be determined by electron capture. One expects the largest influence of the neutrino mass on this decay for a small Q value of Q = 2.8 keV for {}67163\\text{Ho}+e{\\to }66163\\text{Dy}+v. The energy of the Q value is distributed to the emitted neutrino and the excitation of the Dy atom. Thus the energy difference between the Q value and the upper end of the deexcitation spectrum is the electron neutrino mass. The electron wave functions are calculated selfconsistently by the Dirac-Hartree-Fock approach for the bound and the continuum states. To extract the neutrino mass from the spectrum is only possible, if the background is reduced relative to the present situation. The analysis presented here shows, that the determination of the electron neutrino mass by electron capture is difficult, but seems not to be impossible.

  20. Neutrino mass anarchy and the Universe

    Science.gov (United States)

    Lu, Xiaochuan; Murayama, Hitoshi

    2014-08-01

    We study the consequence of the neutrino mass anarchy on cosmology, in particular the total mass of neutrinos and baryon asymmetry through leptogenesis. We require independence of measure in each mass matrix elements in addition to the basis independence, which uniquely picks the Gaussian measure. A simple approximate U(1) flavor symmetry makes leptogenesis highly successful. Correlations between the baryon asymmetry and the light-neutrino quantities are investigated. We also discuss possible implications of recently suggested large total mass of neutrinos by the SDSS/BOSS data.

  1. Probing the Absolute Mass Scale of Neutrinos

    International Nuclear Information System (INIS)

    Formaggio, Joseph A.

    2011-01-01

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

  2. The IBM neutrino-mass experiment

    International Nuclear Information System (INIS)

    Clark, G.J.; Frisch, M.A.; Chaudhari, P.; Bregman, M.F.

    1985-01-01

    IBM is undertaking an experiment to measure the electron anti-neutrino mass. A high precision measurement of the tritium β-decay spectrum near the end point is used to infer the neutrino mass. Electron energies are measured using a large spherical retarding grid analyzer. They are placing particular emphasis on understanding the complications introduced by solid state effects in the source

  3. The IBM neutrino-mass experiment

    International Nuclear Information System (INIS)

    Clark, G.J.; Frisch, M.A.; Chaudhari, P.; Bregman, M.F.

    1985-01-01

    IBM is undertaking an experiment to measure the electron anti-neutrino mass. A high precision measurement of the tritium Β-decay spectrum near the end point is used to infer the neutrino mass. Electron energies are measured using a large spherical retarding grid analyzer. We are placing particular emphasis on understanding the complications introduced by solid state effects in the source

  4. Neutrino masses and mixing in supersymmetric theories

    Indian Academy of Sciences (India)

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

  5. The experimental status of neutrino masses and mixings

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1992-01-01

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

  6. Neutrino mass and mixing with discrete symmetry

    Science.gov (United States)

    King, Stephen F.; Luhn, Christoph

    2013-05-01

    This is a review paper about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of see-saw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A4, S4 and Δ(96).

  7. Neutrino masses, muon g-2, and lepton-flavour violation in the supersymmetric see-saw model

    CERN Document Server

    Hisano, J; Hisano, Junji; Tobe, Kazuhiro

    2001-01-01

    In the light of the recent muon (g_mu-2) result by the E821 experiment at the Brookhaven National Laboratory, we study the event rates of the charged lepton-flavour-violating (LFV) processes in the supersymmetric standard model (SUSY SM) with the heavy right-handed neutrinos (SUSY see-saw model). Since the left-handed sleptons get the LFV masses via the neutrino Yukawa interaction in this model, the event rate of mu->e gamma and the SUSY-SM correction to (g_mu-2)/2 (a_mu(SUSY)) are strongly correlated. When the left-handed sleptons have a LFV mass between the first and second generations ((m^2_L)_{12}) in the mass matrix, it should be suppressed by \\sim 10^{-3} (10^{-9}/a_mu(SUSY)) compared with the diagonal components (m_SUSY^2), from the current experimental bound on mu->e gamma. The recent (g_mu-2) result indicates a_mu(SUSY) \\sim 10^{-9}. The future charged LFV experiments could cover (m^2_L)_{12}/m_SUSY^2 \\gsim 10^{-(5-6)}. These experiments will give a significant impact on the flavour models and the SU...

  8. Understanding neutrino masses and mixings

    Indian Academy of Sciences (India)

    atmospheric neutrino observations, where there is a deficit of observed neutrinos compared to theoretical expectations. ... and reactor neutrinos as in the Kamland experiment have also shown deficits in their flux compared to ... In this brief overview, I wish to draw attention to some of the theoretical ideas for understanding ...

  9. The high mass frontier: limits on heavy neutrinos

    International Nuclear Information System (INIS)

    Gronau, M.

    1984-01-01

    The theoretical motivation for a search for heavy neutrinos is discussed followed by the presentation of typical model dependent expectations for the mixing of the latter with ordinary neutrinos. Present mass and mixing limits on such heavy neutral leptons are based on search for secondary peaks in π and K leptonic decays and on the absence of neutrino decay signatures in neutrino beams from conventional sources and beam dumps. While these limits are quite poor for masses above 1 GeV, we describe methods to extend the limits to masses in the many GeV region. Such limits may be derived from search in b decays, high statistics neutrino experiments, search in ep colliders, W and Z decays and finally - decays of very heavy gauge bosons (if such exist in the TeV region) when produced in multi-TeV pp and antipp colliders

  10. PINGU sensitivity to neutrino mass hierarchy

    Energy Technology Data Exchange (ETDEWEB)

    Groß, Andreas [Technische Universität München, D-85748 Garching (Germany); Collaboration: IceCube-PINGU Collaboration

    2014-11-18

    Determination of the neutrino mass hierarchy (NMH) is among the most fundamental questions in particle physics. Recent measurements of 1) a large mixing angle between the first and the third neutrino mass eigenstates and 2) the first observation of atmospheric neutrino oscillations at tens of GeV with neutrino telescopes, open the intriguing new possibility to exploit matter effects in neutrino oscillation to determine the neutrino mass hierarchy. A further extension of IceCube/DeepCore called PINGU (Precision IceCube Next Generation Upgrade) has been recently envisioned with the ultimate goal to measure neutrino mass hierarchy. PINGU would consist of additional IceCube-like strings of detectors deployed in the deepest and cleanest ice in the center of IceCube. More densely deployed instrumentation would provide a threshold substantially below 10 GeV and enhance the sensitivity to the mass hierarchy signal in atmospheric neutrinos. Here we discuss an estimate of the PINGU sensitivity to the mass hierarchy determined using an approximation with an Asimov dataset and an oscillation parameter fit.

  11. General CP properties of neutrino mass eigenstates

    International Nuclear Information System (INIS)

    Rosen, S.P.

    1984-01-01

    We show that the mass eigenvectors of the neutrino mass matrix have definite CP quantum numbers whether or not CP is conserved, and we examine the conditions under which a mixture of even and odd CP eigenstates will occur

  12. Instability of dark energy with mass-varying neutrinos

    International Nuclear Information System (INIS)

    Afshordi, Niayesh; Zaldarriaga, Matias; Kohri, Kazunori

    2005-01-01

    An interesting dynamical model for dark energy which does not require extremely light scalar fields such as quintessence, and at the same time explains the (near) coincidence between the neutrino and dark energy densities is the model of dark energy coupled to mass-varying neutrinos (MaVaNs). Despite the attractions of this model, we show that, generically, this model contains a catastrophic instability which occurs when neutrinos become nonrelativistic. As a result of this instability, as neutrinos become nonrelativistic, they condense into neutrino nuggets which redshift away similar to cold dark matter, and thus cease to act as dark energy. Any stable MaVaNs dark energy model is extremely contrived and is virtually indistinguishable from a cosmological constant

  13. Model independent bounds on magnetic moments of Majorana neutrinos

    International Nuclear Information System (INIS)

    Bell, Nicole F.; Gorchtein, Mikhail; Ramsey-Musolf, Michael J.; Vogel, Petr; Wang, Peng

    2006-01-01

    We analyze the implications of neutrino masses for the magnitude of neutrino magnetic moments. By considering electroweak radiative corrections to the neutrino mass, we derive model-independent naturalness upper bounds on neutrino magnetic moments, μ ν , generated by physics above the electroweak scale. For Dirac neutrinos, the bound is several orders of magnitude more stringent than present experimental limits. However, for Majorana neutrinos the magnetic moment contribution to the mass is Yukawa suppressed. The bounds we derive for magnetic moments of Majorana neutrinos are weaker than present experimental limits if μ ν is generated by new physics at ∼1 TeV, and surpass current experimental sensitivity only for new physics scales >10-100 TeV. The discovery of a neutrino magnetic moment near present limits would thus signify that neutrinos are Majorana particles

  14. Neutrino masses and ordering via multimessenger astronomy

    DEFF Research Database (Denmark)

    Langæble, Kasper; Meroni, Aurora; Sannino, Francesco

    2016-01-01

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

  15. Neutrino mass and mixing – status

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Vol. 79, No. 5. — journal of. November 2012 physics pp. 979–992. Neutrino mass and mixing – status. THOMAS SCHWETZ. Max-Planck-Institut für Kernphysik, .... addition to being the smoking gun signature for neutrino oscillations, this provides the very accurate determination of m2. 21.

  16. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    the effect of oscillations of neutrinos from a nearby supernova explosion in future detectors will also be discussed. Keywords. Neutrino ... the Chandrasekhar limiting mass the pressure of the relativistic electron gas alone can no longer counterbalance the .... Considering the limiting case of Ц × ^. К, (9) implies К — О . Also,.

  17. Neutrino mass hierarchy and octant determination with atmospheric neutrinos.

    Science.gov (United States)

    Barger, Vernon; Gandhi, Raj; Ghoshal, Pomita; Goswami, Srubabati; Marfatia, Danny; Prakash, Suprabh; Raut, Sushant K; Sankar, S Uma

    2012-08-31

    The recent discovery by the Daya-Bay and RENO experiments, that θ(13) is nonzero and relatively large, significantly impacts existing experiments and the planning of future facilities. In many scenarios, the nonzero value of θ(13) implies that θ(23) is likely to be different from π/4. Additionally, large detectors will be sensitive to matter effects on the oscillations of atmospheric neutrinos, making it possible to determine the neutrino mass hierarchy and the octant of θ(23). We show that a 50 kT magnetized liquid argon neutrino detector can ascertain the mass hierarchy with a significance larger than 4σ with moderate exposure times, and the octant at the level of 2-3σ with greater exposure.

  18. A novel approach to quantifying the sensitivity of current and future cosmological datasets to the neutrino mass ordering through Bayesian hierarchical modeling

    Science.gov (United States)

    Gerbino, Martina; Lattanzi, Massimiliano; Mena, Olga; Freese, Katherine

    2017-12-01

    We present a novel approach to derive constraints on neutrino masses, as well as on other cosmological parameters, from cosmological data, while taking into account our ignorance of the neutrino mass ordering. We derive constraints from a combination of current as well as future cosmological datasets on the total neutrino mass Mν and on the mass fractions fν,i =mi /Mν (where the index i = 1 , 2 , 3 indicates the three mass eigenstates) carried by each of the mass eigenstates mi, after marginalizing over the (unknown) neutrino mass ordering, either normal ordering (NH) or inverted ordering (IH). The bounds on all the cosmological parameters, including those on the total neutrino mass, take therefore into account the uncertainty related to our ignorance of the mass hierarchy that is actually realized in nature. This novel approach is carried out in the framework of Bayesian analysis of a typical hierarchical problem, where the distribution of the parameters of the model depends on further parameters, the hyperparameters. In this context, the choice of the neutrino mass ordering is modeled via the discrete hyperparameterhtype, which we introduce in the usual Markov chain analysis. The preference from cosmological data for either the NH or the IH scenarios is then simply encoded in the posterior distribution of the hyperparameter itself. Current cosmic microwave background (CMB) measurements assign equal odds to the two hierarchies, and are thus unable to distinguish between them. However, after the addition of baryon acoustic oscillation (BAO) measurements, a weak preference for the normal hierarchical scenario appears, with odds of 4 : 3 from Planck temperature and large-scale polarization in combination with BAO (3 : 2 if small-scale polarization is also included). Concerning next-generation cosmological experiments, forecasts suggest that the combination of upcoming CMB (COrE) and BAO surveys (DESI) may determine the neutrino mass hierarchy at a high statistical

  19. Constraining the lightest neutrino mass and mee from general ...

    Indian Academy of Sciences (India)

    Majorana mass mee measured in neutrinoless double beta decay. In this context, the present work aims to make an attempt to obtain some bounds for mee and the lightest neutrino mass using fairly general lepton mass matrices in the Standard Model. Keywords. Lepton mass matrices; neutrinoless double beta decay.

  20. Extended Higgs sectors in radiative neutrino models

    Directory of Open Access Journals (Sweden)

    Oleg Antipin

    2017-05-01

    Full Text Available Testable Higgs partners may be sought within the extensions of the SM Higgs sector aimed at generating neutrino masses at the loop level. We study a viability of extended Higgs sectors for two selected models of radiative neutrino masses: a one-loop mass model, providing the Higgs partner within a real triplet scalar representation, and a three-loop mass model, providing it within its two-Higgs-doublet sector. The Higgs sector in the one-loop model may remain stable and perturbative up to the Planck scale, whereas the three-loop model calls for a UV completion around 106 GeV. Additional vector-like lepton and exotic scalar fields, which are required to close one- and three-loop neutrino-mass diagrams, play a decisive role for the testability of the respective models. We constrain the parameter space of these models using LHC bounds on diboson resonances.

  1. The Neutrino Mass Window for Baryogenesis

    CERN Document Server

    Buchmüller, Wilfried; Plümacher, Michael

    2003-01-01

    Interactions of heavy Majorana neutrinos in the thermal phase of the early universe may be the origin of the cosmological matter-antimatter asymmetry. This mechanism of baryogenesis implies stringent constraints on light and heavy Majorana neutrino masses. We derive an improved upper bound on the CP asymmetry in heavy neutrino decays which, together with the kinetic equations, yields an upper bound on all light neutrino masses of 0.1 eV. Lepton number changing processes at temperatures above the temperature T_B of baryogenesis can erase other, pre-existing contributions to the baryon asymmetry. We find that these washout processes become very efficient if the effective neutrino mass \\tilde{m}_1 is larger than m_* \\simeq 10^{-3} eV. All memory of the initial conditions is then erased. Hence, for neutrino masses in the range from (\\Delta m^2_sol)^{1/2} \\simeq 8*10^{-3} eV to (\\Delta m^2_atm)^{1/2} \\simeq 5*10^{-2} eV, which is suggested by neutrino oscillations, leptogenesis emerges as the unique source of the ...

  2. Neutrino Mixing and Masses from a Minimum Principle

    CERN Document Server

    Alonso, R; Isidori, G; Maiani, L

    2013-01-01

    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 $\\left[SU(3)\\right]^5\\otimes \\mathcal O(3)$ 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 mixing angle close to maximal, a second potentially large, a third one necessarily small, and one maximal relative Majorana phase. 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 and cosmological measurements. The generalization of these results to arbitrary sew-saw models is also discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ng, John N.; Puente, Alejandro de la

    2013-11-25

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

  4. Cosmological and astrophysical neutrino mass measurements

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  5. A model for pseudo-Dirac neutrinos: leptogenesis and ultra-high energy neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Y.H. [Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS),Daejeon, 34051 (Korea, Republic of); Kang, Sin Kyu [Insitute for Convergence Fundamental Study, School of Liberal Arts, Seoul-Tech.,Seoul, 01811 (Korea, Republic of); Kim, C.S. [Dept. of Physics and IPAP, Yonsei University,Seoul, 120-749 (Korea, Republic of)

    2016-10-18

    We propose a model where sterile neutrinos are introduced to make light neutrinos to be pseudo-Dirac particles. It is shown how tiny mass splitting necessary for realizing pseudo-Dirac neutrinos can be achieved. Within the model, we show how leptogenesis can be successfully generated. Motivated by the recent observation of very high energy neutrino events at IceCube, we study a possibility to observe the effects of the pseudo-Dirac property of neutrinos by performing astronomical-scale baseline experiments to uncover the oscillation effects of very tiny mass splitting. We also discuss future prospect to observe the effects of the pseudo-Dirac property of neutrinos at high energy neutrino experiments.

  6. Constraining the lightest neutrino mass and mee from general ...

    Indian Academy of Sciences (India)

    2016-01-25

    Jan 25, 2016 ... Despite spectacular advances in fixing the neutrino mass and mixing parameters through various neutrino oscillation experiments, we still have little knowledge about the magnitudes of some vital parameters in the neutrino sector such as the absolute neutrino mass scale, effective Majorana mass mee ...

  7. Higgs mass from neutrino-messenger mixing

    International Nuclear Information System (INIS)

    Byakti, Pritibhajan; Khosa, Charanjit K.; Mummidi, V.S.; Vempati, Sudhir K.

    2017-01-01

    The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A t , relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

  8. Higgs mass from neutrino-messenger mixing

    Energy Technology Data Exchange (ETDEWEB)

    Byakti, Pritibhajan [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science,2A & 2B Raja S.C. Mullick Road, Kolkata 700 032 (India); Khosa, Charanjit K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Mummidi, V.S. [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Vempati, Sudhir K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India)

    2017-03-06

    The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A{sub t}, relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

  9. The singular seesaw mechanism with hierarchical Dirac neutrino mass

    International Nuclear Information System (INIS)

    Chikira, Y.; Mimura, Y.

    2000-01-01

    The singular seesaw mechanism can naturally explain the atmospheric neutrino deficit by maximal oscillations between ν μ L and ν μ R . This mechanism can also induce three different scales of the neutrino mass squared differences, which can explain the neutrino deficits of three independent experiments (solar, atmospheric, and LSND) by neutrino oscillations. In this paper we show that realistic mixing angles among the neutrinos can be obtained by introducing a hierarchy in the Dirac neutrino mass. In the case where the Majorana neutrino mass matrix has rank 2, the solar neutrino deficit is explained by vacuum oscillations between ν e and ν τ . We also consider the case where the Majorana neutrino mass matrix has rank 1. In this case, the matter enhanced Mikheyev-Smirnov-Wolfenstein solar neutrino solution is preferred as the solution of the solar neutrino deficit. (orig.)

  10. Fermion masses and mixings in the 3-3-1 model with right-handed neutrinos based on the S{sub 3} flavor symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.E.C. [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Martinez, R.; Ochoa, F. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia)

    2016-11-15

    We propose a 3-3-1 model where the SU(3){sub C} x SU(3){sub L} x U(1){sub X} symmetry is extended by S{sub 3} x Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} and the scalar spectrum is enlarged by extra SU(3){sub L} singlet scalar fields. The model successfully describes the observed SM fermion mass and mixing pattern. In this framework, the light active neutrino masses arise via an inverse seesaw mechanism and the observed charged fermion mass and quark mixing hierarchy is a consequence of the Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} symmetry breaking at very high energy. The obtained physical observables for both quark and lepton sectors are compatible with their experimental values. The model predicts the effective Majorana neutrino mass parameter of neutrinoless double beta decay to be m{sub ββ} = 4 and 48 meV for the normal and the inverted neutrino spectra, respectively. Furthermore, we found a leptonic Dirac CP-violating phase close to (π)/(2) and a Jarlskog invariant close to about 3 x 10{sup -2} for both normal and inverted neutrino mass hierarchy. (orig.)

  11. Radiative scaling neutrino mass and warm dark matter

    International Nuclear Information System (INIS)

    Ma, Ernest

    2012-01-01

    A new and radical scenario of the simple 2006 model of radiative neutrino mass is proposed, where there is no seesaw mechanism, i.e. neutrino masses are not inversely proportional to some large mass scale, contrary to the prevalent theoretical thinking. The neutral singlet fermions in the loop have masses of order 10 keV, the lightest of which is absolutely stable and the others are very long-lived. All are components of warm dark matter, which is a possible new paradigm for explaining the structure of the Universe at all scales.

  12. Neutrino transport in black hole-neutron star binaries: Neutrino emission and dynamical mass ejection

    Science.gov (United States)

    Kyutoku, Koutarou; Kiuchi, Kenta; Sekiguchi, Yuichiro; Shibata, Masaru; Taniguchi, Keisuke

    2018-01-01

    We study the merger of black hole-neutron star binaries by fully general-relativistic neutrino-radiation-hydrodynamics simulations throughout the coalescence, particularly focusing on the role of neutrino irradiation in dynamical mass ejection. Neutrino transport is incorporated by an approximate transfer scheme based on the truncated moment formalism. While we fix the mass ratio of the black hole to the neutron star to be 4 and the dimensionless spin parameter of the black hole to be 0.75, the equations of state for finite-temperature neutron-star matter are varied. The hot accretion disk formed after tidal disruption of the neutron star emits a copious amount of neutrinos with the peak total luminosity ˜1 - 3 ×1053 erg s-1 via thermal pair production and subsequent electron/positron captures on free nucleons. Nevertheless, the neutrino irradiation does not modify significantly the electron fraction of the dynamical ejecta from the neutrinoless β -equilibrium value at zero temperature of initial neutron stars. The mass of the wind component driven by neutrinos from the remnant disk is negligible compared to the very neutron-rich dynamical component, throughout our simulations performed until a few tens milliseconds after the onset of merger, for the models considered in this study. These facts suggest that the ejecta from black hole-neutron star binaries are very neutron rich and are expected to accommodate strong r -process nucleosynthesis, unless magnetic or viscous processes contribute substantially to the mass ejection from the disk. We also find that the peak neutrino luminosity does not necessarily increase as the disk mass increases, because tidal disruption of a compact neutron star can result in a remnant disk with a small mass but high temperature.

  13. Remark on natural models of neutrinos

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo

    2005-01-01

    We comment on what 't Hooft's naturalness argument implies with regard to a minimal extension of the Standard Model that incorporates right-handed neutrinos with generic mass terms. If this Lagrangian is taken as that of a low energy effective theory, the idea of pseudo-Dirac neutrinos with very small masses is consistent with 't Hooft's naturalness argument. This argument is based on the observation that the right-handed components of neutrinos in the massless limit exhibit an extra enhanced symmetry which is absent in other charged fermions. This enhanced symmetry is reminiscent of the Nambu-Goldstone fermions associated with spontaneously broken supersymmetry. The conventional seesaw scenario gives another natural solution if the ultra-heavy right-handed neutrinos are integrated out in the formulation of a low energy effective theory. (author)

  14. Remarks on ''Neutrino masses and mixing angles in a predictive theory of fermion masses''

    International Nuclear Information System (INIS)

    Lavoura, L.; Silva, J.P.

    1994-01-01

    In the extension of the Dimopoulos-Hall-Raby model of the fermion mass matrices to the neutrino sector, there is an entry in the up-quark and neutrino Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a 120, instead of a 10 or a 126, of SO(10). Although this assumption leads to an extra undetermined complex parameter in the model, the resulting lepton mixing matrix exhibits the remarkable feature that the ν τ does not mix with the other two neutrinos. Making a reasonable assumption about the extra parameter, we are able to fit the large-mixing-angle MSW solution of the solar-neutrino problem, and we obtain m ντ ∼10 eV, the right mass range to close the Universe. Other possibilities for explaining the solar-neutrino deficit are also discussed

  15. Structure of right-handed neutrino mass matrix

    Science.gov (United States)

    Koide, Yoshio

    2017-11-01

    Recently, Nishiura and the author proposed a unified quark-lepton mass matrix model under a family symmetry U (3 )×U (3 )' . The model can give excellent parameter fitting to the observed quark and neutrino data. The model has a reasonable basis as far as the quark sector, but, in the neutrino sector, the form of the right-handed neutrino mass matrix MR does not have a theoretical basis; that is, it was nothing but a phenomenological assumption. In this paper, it is pointed out that the form of MR is originated in the structure of Majorana mass matrix (4 ×4 matrix) for the left-handed fields ((νL)i,(νRc)i,(NL)α,(NRc)α) where νi (i =1 , 2, 3) and Nα (α =1 , 2, 3) are U(3)-family and U(3 ) ' -family triplets, respectively.

  16. Small Neutrino Masses from Supersymmetry Breaking

    Energy Technology Data Exchange (ETDEWEB)

    Arkani-Hamed, Nima; Hall, Lawrence; Murayama, Hitoshi; Smith, David; Weiner, Neal

    2000-06-27

    An alternative to the conventional see-saw mechanism is proposed to explain the origin of small neutrino masses in supersymmetric theories. The masses and couplings of the right-handed neutrino field are suppressed by supersymmetry breaking, in a way similar to the suppression of the Higgs doublet mass, $\\mu$. New mechanisms for light Majorana, Dirac and sterile neutrinos arise, depending on the degree of suppression. Superpartner phenomenology is greatly altered by the presence of weak scale right-handed sneutrinos, which may have a coupling to a Higgs boson and a left-handed sneutrino. The sneutrino spectrum and couplings are quite unlike the conventional case - the lightest sneutrino can be the dark matter and predictions are given for event rates at upcoming halo dark matter direct detection experiments. Higgs decays and search strategies are changed. Copious Higgs production at hadron colliders can result from cascade decays of squarks and gluinos.

  17. Neutrino Masses and Lepton Flavour Violation in Thick Brane Scenarios

    CERN Document Server

    Barenboim, G; De Gouvêa, A; Rebelo, Margarida N; Barenboim, Gabriela; Gouvea, Andre de

    2001-01-01

    We address the issue of lepton flavour violation and neutrino masses in the ``fat-brane'' paradigm, where flavour changing processes are suppressed by localising different fermion field wave-functions at different positions (in the extra dimensions) in a thick brane. We study the consequences of suppressing lepton number violating charged lepton decays within this scenario for lepton masses and mixing angles. In particular, we find that charged lepton mass matrices are constrained to be quasi-diagonal. We further consider whether the same paradigm can be used to naturally explain small Dirac neutrino masses by considering the existence of three right-handed neutrinos in the brane, and discuss the requirements to obtain phenomenologically viable neutrino masses and mixing angles. Finally, we examine models where neutrinos obtain a small Majorana mass by breaking lepton number in a far away brane and show that, if the fat-brane paradigm is the solution to the absence of lepton number violating charged lepton de...

  18. Probing neutrino masses with CMB lensing extraction

    International Nuclear Information System (INIS)

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

    2006-01-01

    We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and Planck to the nonzero total neutrino mass M ν indicated by current neutrino oscillation data. We find that these experiments greatly benefit from lensing extraction techniques, improving their one-sigma sensitivity to M ν by a factor of order four. The combination of data from Planck and the SAMPAN mini-satellite project would lead to σ(M ν )∼0.1 eV, while a value as small as σ(M ν )∼0.035 eV is within the reach of a space mission based on bolometers with a passively cooled 3-4 m aperture telescope, representative of the most ambitious projects currently under investigation. We show that our results are robust not only considering possible difficulties in subtracting astrophysical foregrounds from the primary CMB signal but also when the minimal cosmological model (Λ Mixed Dark Matter) is generalized in order to include a possible scalar tilt running, a constant equation-of-state parameter for the dark energy and/or extra relativistic degrees of freedom

  19. A Simple Grand Unification View of Neutrino Mixing and Fermion Mass Matrices

    CERN Document Server

    Altarelli, Guido; Altarelli, Guido; Feruglio, Ferruccio

    1999-01-01

    Assuming three light neutrinos and the see-saw mechanism we present a semiquantitative model of fermion masses based on (SUSY) SU(5) and abelian horizontal charges. A good description of the observed pattern of quark and lepton masses is obtained. For neutrinos we naturally obtain widely split masses and large atmospheric neutrino mixing as a consequence of SU(5)-related asymmetric mass matrices for d quarks and charged leptons.

  20. Deconstructing the neutrino mass constraint from galaxy redshift surveys

    Science.gov (United States)

    Boyle, Aoife; Komatsu, Eiichiro

    2018-03-01

    The total mass of neutrinos can be constrained in a number of ways using galaxy redshift surveys. Massive neutrinos modify the expansion rate of the Universe, which can be measured using baryon acoustic oscillations (BAOs) or the Alcock-Paczynski (AP) test. Massive neutrinos also change the structure growth rate and the amplitude of the matter power spectrum, which can be measured using redshift-space distortions (RSD). We use the Fisher matrix formalism to disentangle these information sources, to provide projected neutrino mass constraints from each of these probes alone and to determine how sensitive each is to the assumed cosmological model. We isolate the distinctive effect of neutrino free-streaming on the matter power spectrum and structure growth rate as a signal unique to massive neutrinos that can provide the most robust constraints, which are relatively insensitive to extensions to the cosmological model beyond ΛCDM . We also provide forecasted constraints using all of the information contained in the observed galaxy power spectrum combined, and show that these maximally optimistic constraints are primarily limited by the accuracy to which the optical depth of the cosmic microwave background, τ, is known.

  1. One right-handed neutrino to generate complete neutrino mass spectrum in the framework of NMSSM

    Directory of Open Access Journals (Sweden)

    Yi-Lei Tang

    2015-01-01

    Full Text Available The see-saw mechanism is usually applied to explain the lightness of neutrinos. The traditional see-saw mechanism introduces at least two right-handed neutrinos for the realistic neutrino spectrum. In the case of supersymmetry, loop corrections can also contribute to neutrino masses, which lead to the possibility to generate the neutrino spectrum by introducing just one right-handed neutrino. To be realistic, MSSM suffers from the μ problem and other phenomenological difficulties, so we extend NMSSM (the MSSM with a singlet S by introducing one single right-handed neutrino superfield (N and relevant phenomenology is discussed.

  2. Neutrino physics

    International Nuclear Information System (INIS)

    Gil-Botella, I.

    2011-01-01

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

  3. Neutrino Physics

    CERN Document Server

    Gil-Botella, I.

    2013-06-27

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

  4. QLC relation and neutrino mass hierarchy

    Energy Technology Data Exchange (ETDEWEB)

    Ferrandis, Javier; Pakvasa, Sandip

    2005-01-27

    Latest measurements have revealed that the deviation from a maximal solar mixing angle is approximately the Cabibbo angle, i.e., QLC relation. We argue that it is not plausible that this deviation from maximality, be it a coincidence or not, comes from the charged lepton mixing. Consequently we have calculated the required corrections to the exactly bimaximal neutrino mass matrix ansatz necessary to account for the solar mass difference and the solar mixing angle. We point out that the relative size of these two corrections depends strongly on the hierarchy case under consideration. We find that the inverted hierarchy case with opposite CP parities, which is known to guarantee the RGE stability of the solar mixing angle, offers the most plausible scenario for a high energy origin of a QLC-corrected bimaximal neutrino mass matrix. This possibility may allow us to explain the QLC relation in connection with the origin of the charged fermion mass matrices.

  5. Double beta decays and neutrino masses

    International Nuclear Information System (INIS)

    Ejiri, Hiro

    2006-01-01

    Neutrino-less double beta decays(0νββ) are of great interest for studying the Majorana nature of ν's and the absolute ν-mass scale. The present report is a brief review of the 0νββ studies with emphasis on future experiments with the mass sensitivity of an order of 25∼100 meV and on experimental probes for investigating 0νββ nuclear matrix elements

  6. Supersymmetric unification in the light of neutrino mass

    Indian Academy of Sciences (India)

    Supersymmetry; -parity; Pati–Salam; left–right. ... recently developed minimal left right supersymmetric models with a renormalizable see-saw mechanism for neutrino mass to left right symmetric SUSY GUTS: in ... Author Affiliations. Charanjit S Aulakh1. Department of Physics, Panjab University, Chandigarh 160 019, India ...

  7. Lepton family symmetries for neutrino masses and mixing

    Indian Academy of Sciences (India)

    I then focus on the tetrahedral group A4 and show how the charged-lepton and neutrino mass matrices may be constrained, followed by a catalog of recent models, with one detailed example. I will also discuss the symmetry S4 with another example and mention briefly the symmetry B4. These examples show how exact ...

  8. The next challenge for neutrinos: the mass ordering

    Directory of Open Access Journals (Sweden)

    Stanco Luca

    2017-01-01

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

  9. Neutrino mass priors for cosmology from random matrices

    Science.gov (United States)

    Long, Andrew J.; Raveri, Marco; Hu, Wayne; Dodelson, Scott

    2018-02-01

    Cosmological measurements of structure are placing increasingly strong constraints on the sum of the neutrino masses, Σ mν, through Bayesian inference. Because these constraints depend on the choice for the prior probability π (Σ mν), we argue that this prior should be motivated by fundamental physical principles rather than the ad hoc choices that are common in the literature. The first step in this direction is to specify the prior directly at the level of the neutrino mass matrix Mν, since this is the parameter appearing in the Lagrangian of the particle physics theory. Thus by specifying a probability distribution over Mν, and by including the known squared mass splittings, we predict a theoretical probability distribution over Σ mν that we interpret as a Bayesian prior probability π (Σ mν). Assuming a basis-invariant probability distribution on Mν, also known as the anarchy hypothesis, we find that π (Σ mν) peaks close to the smallest Σ mν allowed by the measured mass splittings, roughly 0.06 eV (0.1 eV) for normal (inverted) ordering, due to the phenomenon of eigenvalue repulsion in random matrices. We consider three models for neutrino mass generation: Dirac, Majorana, and Majorana via the seesaw mechanism; differences in the predicted priors π (Σ mν) allow for the possibility of having indications about the physical origin of neutrino masses once sufficient experimental sensitivity is achieved. We present fitting functions for π (Σ mν), which provide a simple means for applying these priors to cosmological constraints on the neutrino masses or marginalizing over their impact on other cosmological parameters.

  10. Cosmological constraints on the neutrino mass including systematic uncertainties

    Science.gov (United States)

    Couchot, F.; Henrot-Versillé, S.; Perdereau, O.; Plaszczynski, S.; Rouillé d'Orfeuil, B.; Spinelli, M.; Tristram, M.

    2017-10-01

    When combining cosmological and oscillations results to constrain the neutrino sector, the question of the propagation of systematic uncertainties is often raised. We address this issue in the context of the derivation of an upper bound on the sum of the neutrino masses (Σmν) with recent cosmological data. This work is performed within the ΛCDM model extended to Σmν, for which we advocate the use of three mass-degenerate neutrinos. We focus on the study of systematic uncertainties linked to the foregrounds modelling in cosmological microwave background (CMB) data analysis, and on the impact of the present knowledge of the reionisation optical depth. This is done through the use of different likelihoods built from Planck data. Limits on Σmν are derived with various combinations of data, including the latest baryon acoustic oscillations (BAO) and Type Ia supernovae (SNIa) results. We also discuss the impact of the preference for current CMB data for amplitudes of the gravitational lensing distortions higher than expected within the ΛCDM model, and add the Planck CMB lensing. We then derive a robust upper limit: Σmνcosmological parameters is also reported, for different assumptions on the neutrino mass repartition, and different high and low multipole CMB likelihoods.

  11. Theory of Neutrino Masses and Mixing

    CERN Document Server

    González-Garciá, M Concepción

    2003-01-01

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

  12. Mass limits for the muon neutrino

    International Nuclear Information System (INIS)

    Hoffman, C.M.; Sandberg, V.D.

    1982-01-01

    The possibility of improving the present limit on the mass of the muon neutrino is discussed. It is found that decays of muons and pions are not useful means to significantly improve this limit. On the other hand, the decays K 0 /sub L/ → π/sup +-/μ/sup -+/nu/sub μ/ and K + → π 0 μ + nu/sub μ/ appear to be quite promising. Possible experiments are discussed

  13. Gauge Anomalies and Neutrino Seesaw Models

    CERN Document Server

    Neves Cebola, Luis Manuel

    Despite the success of the Standard Model concerning theoretical predictions, there are several experimental results that cannot be explained and there are reasons to believe that there exists new physics beyond it. Neutrino oscillations, and hence their masses, are examples of this. Experimentally it is known that neutrinos masses are quite small, when compared to all Standard Model particle masses. Among the theoretical possibilities to explain these tiny masses, the seesaw mechanism is a simple and well-motivated framework. In its minimal version, heavy particles are introduced that decouple from the theory in the early universe. To build consistent theories, classical symmetries need to be preserved at quantum level, so that there are no anomalies. The cancellation of these anomalies leads to constraints in the parameters of the theory. One attractive solution is to realize the anomaly cancellation through the modication of the gauge symmetry. In this thesis we present a short review of some features of t...

  14. Cosmology and the neutrino mass ordering

    DEFF Research Database (Denmark)

    Hannestad, Steen; Schwetz, Thomas

    2016-01-01

    We propose a simple method to quantify a possible exclusion of the inverted neutrino mass ordering from cosmological bounds on the sum of the neutrino masses. The method is based on Bayesian inference and allows for a calculation of the posterior odds of normal versus inverted ordering. We apply...... the method for a specific set of current data from Planck CMB data and large-scale structure surveys, providing an upper bound on the sum of neutrino masses of 0.14 eV at 95% CL. With this analysis we obtain posterior odds for normal versus inverted ordering of about 2:1. If cosmological data is combined...... with data from oscillation experiments the odds reduce to about 3:2. For an exclusion of the inverted ordering from cosmology at more than 95% CL, an accuracy of better than 0.02 eV is needed for the sum. We demonstrate that such a value could be reached with planned observations of large scale structure...

  15. Lepton family symmetries for neutrino masses and mixing

    Indian Academy of Sciences (India)

    on the tribimaximal mixing ansatz of Harrison, Perkins and Scott. Keywords. Neutrino mixing; discrete symmetry. PACS Nos 14.60.Pq; 11.30.Hv. 1. Some basics. Using present data from neutrino oscillations, the 3 × 3 neutrino mixing matrix is largely determined, together with the two mass-squared differences [1]. In the Stan-.

  16. Weighing neutrinos in Finslerian cosmological models

    Science.gov (United States)

    Wang, Deng; Meng, Xin-He

    2017-07-01

    To explore the neutrino physics in the framework of Finsler geometry, we perform constraints on five cosmological models using the most stringent constraint we can provide so far. For the first time, we give the 95% limits of the total mass of three active neutrinos Σ mν for three Finslerian models in the presence of massive neutrinos. We find that the base Finslerian model, a two-parameter extension to the Λ CDM model based on the Finsler geometry, can fit better to current data than the other four models, and that the values of constrained effective typical parameters α and β in four Finslerian models are all consistent with zero at the 1 σ confidence level (CL), indicating that four Finslerian models just deviate very slightly from the Λ CDM model. For the base Finslerian model with a constant equation of state (EoS) of dark energy (DE) and massive neutrinos, we obtain a tighter constraint on the EoS of DE, which is more stringent than Planck's prediction by one order of magnitude. For the nonflat base Finslerian model with massive neutrinos, we find that our measured value of spatial curvature is in a strong tension with a flat universe at the 2.45 σ CL. However, if fixing Σ mν=0.06 eV with a normal hierarchy, this tension vanishes, i.e., a flat universe is still preferred in the nonflat base Finslerian model. We also find that the current H0 tension can be effectively alleviated by four Finslerian models.

  17. Neutrino Textures in the Light of Super-Kamiokande Data and a Realistic String Model

    CERN Document Server

    Ellis, Jonathan Richard; Lola, S; Nanopoulos, Dimitri V

    1999-01-01

    Motivated by the Super-Kamiokande atmospheric neutrino data, we discuss possible textures for Majorana and Dirac neutrino masses within the see-saw framework. The main purposes of this paper are twofold: first to obtain intuition from a purely phenomenological analysis, and secondly to explore to what extent it may be realized in a specific model. We comment initially on the simplified two-generation case, emphasizing that large mixing is not incompatible with a large hierarchy of mass eigenvalues. We also emphasize that renormalization-group effects may amplify neutrino mixing, presenting semi-analytic expressions for estimating this amplification. Several examples are then given of three-family neutrino mass textures which may also accommodate the persistent solar neutrino deficit, with different assumptions for the neutrino Dirac mass matrices. We comment on a few features of neutrino mass textures arising in models with a U(1) flavour symmetry. Finally, we discuss the possible pattern of neutrino masses i...

  18. Dark matter stability and one-loop neutrino mass generation based on Peccei-Quinn symmetry

    Science.gov (United States)

    Suematsu, Daijiro

    2018-01-01

    We propose a model which is a simple extension of the KSVZ invisible axion model with an inert doublet scalar. Peccei-Quinn symmetry forbids tree-level neutrino mass generation and its remnant Z_2 symmetry guarantees dark matter stability. The neutrino masses are generated by one-loop effects as a result of the breaking of Peccei-Quinn symmetry through a nonrenormalizable interaction. Although the low energy effective model coincides with an original scotogenic model which contains right-handed neutrinos with large masses, it is free from the strong CP problem.

  19. Relaxing neutrino mass bounds by a running cosmological constant

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, F.; Schrempp, L.

    2007-11-15

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

  20. Sneutrino dark matter in gauged inverse seesaw models for neutrinos.

    Science.gov (United States)

    An, Haipeng; Dev, P S Bhupal; Cai, Yi; Mohapatra, R N

    2012-02-24

    Extending the minimal supersymmetric standard model to explain small neutrino masses via the inverse seesaw mechanism can lead to a new light supersymmetric scalar partner which can play the role of inelastic dark matter (IDM). It is a linear combination of the superpartners of the neutral fermions in the theory (the light left-handed neutrino and two heavy standard model singlet neutrinos) which can be very light with mass in ~5-20 GeV range, as suggested by some current direct detection experiments. The IDM in this class of models has keV-scale mass splitting, which is intimately connected to the small Majorana masses of neutrinos. We predict the differential scattering rate and annual modulation of the IDM signal which can be testable at future germanium- and xenon-based detectors.

  1. Neutrino mass matrices with one texture equality and one vanishing neutrino mass

    Science.gov (United States)

    Han, Jinzhong; Wang, Ruihong; Wang, Weijian; Wei, Xing-Ning

    2017-10-01

    In the light of latest data of neutrino oscillation experiments, we carry out a systematic investigation on the texture structures of Majorana neutrino mass matrix Mν, which contain one vanishing neutrino mass and an equality between two matrix elements. Among 15 logically possible patterns, it is found that for norm order (m3>m2>m1=0 ) of neutrino masses only three of them are compatible with recent experimental data at the 3 σ level, while for inverted order (m2>m1>m3=0 ) two patterns is phenomenologically allowed. In the numerical analysis, we perform a scan over the parameter space of all viable patterns to get a large sample of scattering points. We present the implications of each allowed pattern for three mixing angles (θ12,θ2,θ3), leptonic C P violation and neutrinoless double-beta decay, predicting strong correlations between oscillation parameters. The theoretical realization of a concrete example is discussed in the framework of Froggatt-Nielsen mechanism.

  2. Complex scaling and residual flavour symmetry in the neutrino mass ...

    Indian Academy of Sciences (India)

    2017-10-09

    Oct 9, 2017 ... Using the residual symmetry approach, we propose a complex extension of the scaling ansatz on the neutrino Majorana mass matrix M ν which allows a nonzero mass for each of the three light neutrinos as well as a nonvanishing θ 13 . Leptonic Dirac CP violation must be maximal while atmospheric ...

  3. Neutrino astrophysics

    International Nuclear Information System (INIS)

    Roulet, E.

    2001-01-01

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

  4. Neutrino physics

    CERN Document Server

    Hernandez, P.

    2016-01-01

    This is the writeup of the lectures on neutrino physics delivered at various schools: TASI and Trieste in 2013 and the CERN-Latin American School in 2015. The topics discussed in this lecture include: general properties of neutrinos in the SM, the theory of neutrino masses and mixings (Dirac and Majorana), neutrino oscillations both in vacuum and in matter, as well as an overview of the experimental evidence for neutrino masses and of the prospects in neutrino oscillation physics. We also briefly review the relevance of neutri- nos in leptogenesis and in beyond-the-Standard-Model physics.

  5. Neutrino mass matrix suppression by Abelian charges with see-saw mechanism

    CERN Document Server

    Nielsen, Holger Bech

    2000-01-01

    We have investigated a neutrino mass matrix model without supersymmetry including three see-saw right-handed neutrinos around order $10^{12}$ GeV masses, aiming at a picture with all small numbers explained as being due to approximately conserved gauge charges. The prediction of the solar neutrino mixing angle is given by $\\sin^22\\theta_{\\odot}= 3 {+3\\atop -2}\\times10^{-2}$; in fact, the solar mixing angle is, apart from detailed order unity corrections, equal to the Cabibbo angle. Furthermore the ratio of the solar neutrino mass square difference to that for the atmospheric neutrino oscillation is predicted to $6 {+11\\atop -4}\\times10^{-4}$ and is given by the same Cabibbo angle related parameter $\\xi$ as $6 \\xi^4$.

  6. Cosmological implication of massive neutrinos in a horizontal model context

    International Nuclear Information System (INIS)

    Goldman, C.

    1985-04-01

    An extended version of the Glashow-Weinberg-Salam model for the eletroweak interactions is studied in detail. It has an extra global horizontal symmetry, which allows the appearance of neutrino mass terms. The constraints imposed by the standard cosmological model were used to determine the allowed range of variations of the free parameters of this model. As applications, the solar neutrinos problem and the formation of large scale structures in the universe is studied. (Author) [pt

  7. Majorana neutrino masses and the neutrinoless double-beta decay

    International Nuclear Information System (INIS)

    Faessler, A.

    2006-01-01

    Neutrinoless double-beta decay is forbidden in the Standard Model of electroweak and strong interaction but allowed in most Grand Unified Theories (GUTs). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass is neutrinoless double-beta decay allowed. Apart from one claim that the neutrinoless double-beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow one to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUTs and the minimal R-parity-violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUTs. For that, one has to assume that the specific mechanism is the leading one for neutrinoless double-beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present work, one discusses the accuracy of the present status of calculating of the nuclear matrix elements and the corresponding limits of GUTs and supersymmetric parameters

  8. Towards a unified model of neutrino-nucleus reactions for neutrino oscillation experiments

    Science.gov (United States)

    Nakamura, S. X.; Kamano, H.; Hayato, Y.; Hirai, M.; Horiuchi, W.; Kumano, S.; Murata, T.; Saito, K.; Sakuda, M.; Sato, T.; Suzuki, Y.

    2017-05-01

    A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the Δ (1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a Δ -hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments.

  9. Phenomenological study of extended seesaw model for light sterile neutrino

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Newton [Physical Research Laboratory,Navarangpura, Ahmedabad 380 009 (India); Indian Institute of Technology,Gandhinagar, Ahmedabad-382424 (India); Ghosh, Monojit [Department of Physics, Tokyo Metropolitan University,Hachioji, Tokyo 192-0397 (Japan); Goswami, Srubabati [Physical Research Laboratory,Navarangpura, Ahmedabad 380 009 (India); Gupta, Shivani [Center of Excellence for Particle Physics (CoEPP), University of Adelaide,Adelaide SA 5005 (Australia)

    2017-03-14

    We study the zero textures of the Yukawa matrices in the minimal extended type-I seesaw (MES) model which can give rise to ∼ eV scale sterile neutrinos. In this model, three right handed neutrinos and one extra singlet S are added to generate a light sterile neutrino. The light neutrino mass matrix for the active neutrinos, m{sub ν}, depends on the Dirac neutrino mass matrix (M{sub D}), Majorana neutrino mass matrix (M{sub R}) and the mass matrix (M{sub S}) coupling the right handed neutrinos and the singlet. The model predicts one of the light neutrino masses to vanish. We systematically investigate the zero textures in M{sub D} and observe that maximum five zeros in M{sub D} can lead to viable zero textures in m{sub ν}. For this study we consider four different forms for M{sub R} (one diagonal and three off diagonal) and two different forms of (M{sub S}) containing one zero. Remarkably we obtain only two allowed forms of m{sub ν} (m{sub eτ}=0 and m{sub ττ}=0) having inverted hierarchical mass spectrum. We re-analyze the phenomenological implications of these two allowed textures of m{sub ν} in the light of recent neutrino oscillation data. In the context of the MES model, we also express the low energy mass matrix, the mass of the sterile neutrino and the active-sterile mixing in terms of the parameters of the allowed Yukawa matrices. The MES model leads to some extra correlations which disallow some of the Yukawa textures obtained earlier, even though they give allowed one-zero forms of m{sub ν}. We show that the allowed textures in our study can be realized in a simple way in a model based on MES mechanism with a discrete Abelian flavor symmetry group Z{sub 8}×Z{sub 2}.

  10. Neutrino oscillation observables from mass matrix structure

    International Nuclear Information System (INIS)

    Winter, Walter

    2008-01-01

    We present a systematic procedure to establish a connection between complex neutrino mass matrix textures and experimental observables, including the Dirac CP phase. In addition, we illustrate how future experimental measurements affect the selection of textures in the (θ 13 ,δ CP )-plane. For the mixing angles, we use generic assumptions motivated by quark-lepton complementarity. We allow for any combination between U l and U ν , as well as we average over all present complex phases. We find that individual textures lead to very different distributions of the observables, such as to large or small leptonic CP violation. In addition, we find that the extended quark-lepton complementarity approach motivates future precision measurements of δ CP at the level of θ C ≅11 deg

  11. Majorana equations and the rest mass of neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    von Borzeszkowski, H.; Treder, H.

    1985-02-01

    As is well known, the law of parity conservation does not hold in weak interactions. This type of asymmetry created a number of theoretical problems which were solved, first of all, by a new understanding of the features of neutrinos and their role in weak interactions. These solutions were based, however, essentially on the handedness (chirality) of neutrinos which is closely related to their vanishing rest mass. The thesis of neutrinos with nonvanishing rest mass, newly considered in the literature, therefore requires a rediscussion of the early arguments concerning the relation between the neutrino theory and some weak interaction essentials. When one does this, as in the present paper, it is noted that neutrinos with rest mass lead to some difficulties, in particular to a violation of T invariance.

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

    Indian Academy of Sciences (India)

    The neutrino mass matrix and (selected) variants of A4. MARTIN HIRSCH. AHEP Group, Instituto de Fısica Corpuscular – C.S.I.C./Universitat de Val`encia,. Edificio de Institutos de Paterna, Apartado 22085, E-46071 Val`encia, Spain. E-mail: mahirsch@ific.uv.es. Abstract. Recent neutrino oscillation experiments have ...

  13. Neutrino mass bounds from neutrinoless double beta-decays and ...

    Indian Academy of Sciences (India)

    2016-01-21

    Jan 21, 2016 ... We investigate the way the total mass sum of neutrinos can be constrained from the neutrinoless double beta-decay and cosmological probes with cosmic microwave background (CMBR), large-scale structures including 2dFGRS and SDSS datasets. First we discuss, in brief, the current status of neutrino ...

  14. KATRIN and sterile Neutrinos in the eV mass range

    Energy Technology Data Exchange (ETDEWEB)

    Korzeczek, Marc [Karlsruhe Institute of Technology (Germany); Lasserre, Thierry [Commissariat a l' energie atomique (France); Mertens, Susanne [Karlsruhe Institute of Technology (Germany); Lawrence Berkeley National Laboratory (United States); Collaboration: KATRIN-Collaboration

    2016-07-01

    Sterile neutrinos in the eV-mass range could resolve a number of longstanding anomalies in short baseline neutrino oscillation experiments. The KATRIN Experiment (KArlsruhe TRItium Neutrino) designed to measure the mass of the active neutrino, has the potential to search for a signature of light sterile neutrinos without any hardware modification. In this talk we explore the combined sensitivity of KATRIN with CeSOX (CErium Short distance neutrino Oscillations with boreXino), an experiment dedicated to search for light sterile neutrinos via oscillations. In particular, we study the impact of sterile neutrinos on the KATRIN's active neutrino mass measurement.

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

    CERN Multimedia

    Johnson, G

    2002-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-15

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

  17. Gravity wave and neutrino bursts from stellar collapse: A sensitive test of neutrino masses

    International Nuclear Information System (INIS)

    Arnaud, N.; Barsuglia, M.; Bizouard, M.A.; Cavalier, F.; Davier, M.; Hello, P.; Pradier, T.

    2002-01-01

    New methods are proposed with the goal to determine absolute neutrino masses from the simultaneous observation of the bursts of neutrinos and gravitational waves emitted during a stellar collapse. It is shown that the neutronization electron neutrino flash and the maximum amplitude of the gravitational wave signal are tightly synchronized with the bounce occurring at the end of the core collapse on a time scale better than 1 ms. The existing underground neutrino detectors (SuperKamiokande, SNO,...) and the gravity wave antennas soon to operate (LIGO, VIRGO,...) are well matched in their performance for detecting galactic supernovae and for making use of the proposed approach. Several methods are described, which apply to the different scenarios depending on neutrino mixing. Given the present knowledge on neutrino oscillations, the methods proposed are sensitive to a mass range where neutrinos would essentially be mass degenerate. The 95% C.L. upper limit which can be achieved varies from 0.75 eV/c 2 for large ν e survival probabilities to 1.1 eV/c 2 when in practice all ν e 's convert into ν μ 's or ν τ 's. The sensitivity is nearly independent of the supernova distance

  18. Interplay of type I and type II seesaw contributions to neutrino mass

    International Nuclear Information System (INIS)

    Akhmedov, Evgeny Kh.; Frigerio, Michele

    2007-01-01

    Type I and type II seesaw contributions to the mass matrix of light neutrinos are inherently related if left-right symmetry is realized at high energy scales. We investigate implications of such a relation for the interpretation of neutrino data. We proved recently that the left-right symmetric seesaw equation has eight solutions, related by a duality property, for the mass matrix of right-handed neutrinos M R . In this paper the eight allowed structures of M R are reconstructed analytically and analyzed numerically in a bottom-up approach. We study the dependence of right-handed neutrino masses on the mass spectrum of light neutrinos, mixing angle θ 13 , leptonic CP violation, scale of left-right symmetry breaking and on the hierarchy in neutrino Yukawa couplings. The structure of the seesaw formula in several specific SO(10) models is explored in the light of the duality. The outcome of leptogenesis may depend crucially on the choice among the allowed structures of M R and on the level crossing between right-handed neutrino masses

  19. Neutrinos: Theory and Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Parke, Stephen

    2013-10-22

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

  20. Limits on neutrino masses from tritium beta decay

    CERN Document Server

    Bonn, J; Bornschein, L; Flatt, B; Kraus, C V; Otten, E W; Schall, J P; Thuemmler, T; Weinheimer, C

    2002-01-01

    The presently lowest limit for the mass of the electron neutrino is m nu < 2.2 eV (95 % C.L.) derived from measurements at Mainz up to 1999. The data taken in 2000 are not fully analyzed yet but limits of possible distortions as reported by the Troitsk group can be given. The next generation neutrino mass experiment KATRIN is briefly discussed.

  1. Gif 2011 school: neutrinos. Slides of the presentations

    International Nuclear Information System (INIS)

    Smirnov, A.; Pascoli, S.; Piquemal, F.; Lasserre, T.; Kouchner, A.; Patzak, T.; Lavignac, S.; Volpe, C.; Katsanevas, S.; Rubbia, A.

    2012-01-01

    This document gathers the slides of the lectures given at the GIF 2011 school. These lectures were pedagogical reviews of both theoretical and experimental physics around neutrino issues. There were 9 lectures: 1) the origin of the neutrino mass, 2) theory of neutrino oscillations, 3) measuring the neutrino mass, 4) measuring the neutrino oscillation parameters, 5) astronomy with neutrinos, 6) the story of the neutrino, 7) neutrinos beyond the standard model, 8) neutrinos in cosmology, and 9) future experiments. (A.C.)

  2. Neutrino clustering and the Z-burst model

    International Nuclear Information System (INIS)

    McKellar, B.H.J.; Garbutt, M.; Stephenson, G.J.; Goldman, T.

    2001-01-01

    The possibility that the observed Ultra High Energy Cosmic Rays are generated by high energy neutrinos creating 'Z-bursts' in resonant interactions with the background neutrinos has been proposed, but there are difficulties in generating enough events with reasonable incident neutrino fluxes. We point out that this difficulty is overcome if the background neutrinos have coalesced into 'neutrino clouds' - a possibility previously suggested by some of us in another context. The limitations that this mechanism for the generation of UHECRs places on the high energy neutrino flux, on the masses of the background neutrinos and the characteristics of the neutrino clouds are discussed

  3. Neutrino Masses with Inverse Hierarchy from Broken $L_{e}-L_{\\mu}-L_{\\tau}$: a Reappraisal

    CERN Document Server

    Altarelli, Guido; Altarelli, Guido; Franceschini, Roberto

    2006-01-01

    We discuss a class of models of neutrino masses and mixings with inverse hierarchy based on a broken U(1)_F flavour symmetry with charge L_e-L_\\mu-L_\\tau. The symmetry breaking sector receives separate contributions from flavon vev breaking terms and from soft mass breaking in the right handed Majorana sector. The model is able to reproduce in a natural way all observed features of the charged lepton mass spectrum and of neutrino masses and mixings (even with arbitrarily small \\theta_{13}), with the exception of a moderate fine tuning which is needed to accomodate the observed small value of r = Delta m^2_{sol} / Delta m^2_{atm}.

  4. Radiative stability of neutrino-mass textures

    Indian Academy of Sciences (India)

    .Нv; 12.15.Lk. A major challenge to particle physics at present is the theoretical understanding of experimentally observed neutrino anomalies. Whereas the observed mixing between quarks are small, experimental data favor two large mixings ...

  5. The Nonlinear cosmological matter power spectrum with massive neutrinos. 1. The Halo model

    Energy Technology Data Exchange (ETDEWEB)

    Abazajian, Kevork; /Los Alamos; Switzer, Eric R.; /Princeton U.; Dodelson, Scott; /Fermilab /Chicago U., Astron. Astrophys. Ctr.; Heitmann, Katrin; Habib, Salman; /Los

    2004-11-01

    Measurements of the linear power spectrum of galaxies have placed tight constraints on neutrino masses. We extend the framework of the halo model of cosmological nonlinear matter clustering to include the effect of massive neutrino infall into cold dark matter (CDM) halos. The magnitude of the effect of neutrino clustering for three degenerate mass neutrinos with m{sub v{sub 1}} = 0.9 eV is of order {approx}1%, within the potential sensitivity of upcoming weak lensing surveys. In order to use these measurements to further constrain--or eventually detect--neutrino masses, accurate theoretical predictions of the nonlinear power spectrum in the presence of massive neutrinos will be needed, likely only possible through high-resolution multiple particle (neutrino, CDM and baryon) simulations.

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

    CERN Multimedia

    Witten, Edward

    2002-01-01

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

  7. Neutrino Mass Textures from Oscillations with Maximal Mixing

    CERN Document Server

    Altarelli, Guido; Altarelli, Guido; Feruglio, Ferruccio

    1998-01-01

    We study the implications of neutrino oscillations with maximal mixing for the neutrino Dirac and Majorana matrices in the see-saw mechanism for three non degenerate neutrino masses. We find the form of the Dirac matrix for a structure-less Majorana matrix and, conversely, the structure of the Majorana matrix if the Dirac matrix is according to our naive intuition. We give some examples of Majorana matrices that, in a 3 X 3 context, lead to maximal mixing without too much fine tuning and cross talk with the Dirac input.

  8. Do Small-Mass Neutrinos Participate in Gauge Transformations?

    Directory of Open Access Journals (Sweden)

    Y. S. Kim

    2016-01-01

    Full Text Available Neutrino oscillation experiments presently suggest that neutrinos have a small but finite mass. If neutrinos have mass, there should be a Lorentz frame in which they can be brought to rest. This paper discusses how Wigner’s little groups can be used to distinguish between massive and massless particles. We derive a representation of the SL(2,c group which separates out the two sets of spinors: one set is gauge dependent and the other set is gauge invariant and represents polarized neutrinos. We show that a similar calculation can be done for the Dirac equation. In the large-momentum/zero-mass limit, the Dirac spinors can be separated into large and small components. The large components are gauge invariant, while the small components are not. These small components represent spin-1/2 non-zero-mass particles. If we renormalize the large components, these gauge invariant spinors represent the polarization of neutrinos. Massive neutrinos cannot be invariant under gauge transformations.

  9. Emission line models for the lowest mass core-collapse supernovae - I. Case study of a 9 M⊙ one-dimensional neutrino-driven explosion

    Science.gov (United States)

    Jerkstrand, A.; Ertl, T.; Janka, H.-T.; Müller, E.; Sukhbold, T.; Woosley, S. E.

    2018-03-01

    A large fraction of core-collapse supernovae (CCSNe), 30-50 per cent, are expected to originate from the low-mass end of progenitors with MZAMS = 8-12 M⊙. However, degeneracy effects make stellar evolution modelling of such stars challenging, and few predictions for their supernova light curves and spectra have been presented. Here, we calculate synthetic nebular spectra of a 9 M⊙ Fe CCSN model exploded with the neutrino mechanism. The model predicts emission lines with FWHM ˜ 1000 km s-1, including signatures from each deep layer in the metal core. We compare this model to the observations of the three subluminous IIP SNe with published nebular spectra; SN 1997D, SN 2005cs and SN 2008bk. The predictions of both line profiles and luminosities are in good agreement with SN 1997D and SN 2008bk. The close fit of a model with no tuning parameters provides strong evidence for an association of these objects with low-mass Fe CCSNe. For SN 2005cs, the interpretation is less clear, as the observational coverage ended before key diagnostic lines from the core had emerged. We perform a parametrized study of the amount of explosively made stable nickel, and find that none of these three SNe show the high 58Ni/56Ni ratio predicted by current models of electron capture SNe (ECSNe) and ECSN-like explosions. Combined with clear detection of lines from O and He shell material, these SNe rather originate from Fe core progenitors. We argue that the outcome of self-consistent explosion simulations of low-mass stars, which gives fits to many key observables, strongly suggests that the class of subluminous Type IIP SNe is the observational counterpart of the lowest mass CCSNe.

  10. Constraining the lightest neutrino mass and mee from general ...

    Indian Academy of Sciences (India)

    - trino masses as compared to their charged ... The purpose of the present work, therefore, is to make an attempt to obtain bounds for mee and the lightest neutrino mass by considering the fairly general lepton mass matrices in the SM using the ...

  11. Neutrino mass patterns, ¡ -parity violating supersymmetry and ...

    Indian Academy of Sciences (India)

    physics answering to a neutrino mass pattern of the suggested type. There are, however, a very large number of possibilities to explore, and the credibility of any .... Also, one has to address the question as to whether the treatment of x and x. % as mass eigenstates is proper, from the viewpoint of the charged lepton mass ...

  12. Neutrino mass bounds from neutrinoless double beta-decays and ...

    Indian Academy of Sciences (India)

    2016-01-21

    Jan 21, 2016 ... where νi is the field of neutrino with mass mi and U is the unitary mixing matrix. Neglec- ting the recoil of ... (10), for normal and inverted hierarchy respectively, in terms of mixing angles and 2 s = m2 ..... ical evolution of the sound speed of neutrinos cs = δPν/δρν with the wavenumber k = 2.3 × 10−3 Mpc−1, ...

  13. Status of Neutrino Mass and Mixing

    CERN Document Server

    Altarelli, Guido

    2014-01-01

    In the last two decades experiments have established the existence of neutrino oscillations and most of the related parameters have by now been measured with reasonable accuracy. These results have accomplished a major progress for particle physics and cosmology. At present neutrino physics is a most vital domain of particle physics and cosmology and the existing open questions are of crucial importance. We review the present status of the subject, the main lessons that we have learnt so far and discuss the great challenges that remain in this field.

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

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Kinney, William H. [University at Buffalo, Department of Physics, Buffalo, NY (United States); Park, Wan-Il [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Chonbuk National University, Division of Science Education and Institute of Fusion Science, Jeonju (Korea, Republic of)

    2017-09-15

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

  15. Direct measurement of neutrino mass utilizing beta decay of tritium

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hirokane (Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study)

    1992-10-01

    Among elementary particles, neutrino is the queer, wondrous elementary particle that has asymmetric property, and in spite of strenuous efforts, its mass has not been determined. The mass value expected for electron neutrino is as extremely small as several tens eV, but its value may control the future of the space whether this vast space continues to expand as it is or turns to contract. Accordingly, it has become a very important subject for space physics as well as elementary particle physics. The mass of neutrino has been considered to be nearly zero, but in 1980, the USSR group gave the finite value of 14-46 eV for the first time. Since then, the experiments for verifying this result were begun in more than ten places in the world. The method of measuring the mass of neutrino is that by precisely measuring with a beta ray analyzer the vicinity of the maximum value in the continuous energy spectra of the electron beam emitted simultaneously with neutrinos in the beta decay of tritium, and determining the mass from its form. [pi][radical]2 type air core beta ray analyzer, beta ray source, electron detector, the comparison of the contents of the published experiments, and the results of measurement are reported. (K.I.).

  16. Neutrino CP violation and sign of baryon asymmetry in the minimal seesaw model

    Science.gov (United States)

    Shimizu, Yusuke; Takagi, Kenta; Tanimoto, Morimitsu

    2018-03-01

    We discuss the correlation between the CP violating Dirac phase of the lepton mixing matrix and the cosmological baryon asymmetry based on the leptogenesis in the minimal seesaw model with two right-handed Majorana neutrinos and the trimaximal mixing for neutrino flavors. The sign of the CP violating Dirac phase at low energy is fixed by the observed cosmological baryon asymmetry since there is only one phase parameter in the model. According to the recent T2K and NOνA data of the CP violation, the Dirac neutrino mass matrix of our model is fixed only for the normal hierarchy of neutrino masses.

  17. Minimal models for axion and neutrino

    Directory of Open Access Journals (Sweden)

    Y.H. Ahn

    2016-01-01

    Full Text Available The PQ mechanism resolving the strong CP problem and the seesaw mechanism explaining the smallness of neutrino masses may be related in a way that the PQ symmetry breaking scale and the seesaw scale arise from a common origin. Depending on how the PQ symmetry and the seesaw mechanism are realized, one has different predictions on the color and electromagnetic anomalies which could be tested in the future axion dark matter search experiments. Motivated by this, we construct various PQ seesaw models which are minimally extended from the (non- supersymmetric Standard Model and thus set up different benchmark points on the axion–photon–photon coupling in comparison with the standard KSVZ and DFSZ models.

  18. Neutrino mass and mixing – status

    Indian Academy of Sciences (India)

    dashed curves) the improvement of the fit is not significant, with a χ2 between the best-fit points and the no-oscillation case of only 3.6 and 4.4 for the 3+1 and 3+2 hypotheses, respectively. 5. Global data and the status of eV-scale sterile neutrinos.

  19. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    process nucleosyn- thesis and .... fractions respectively and М s are the temperatures of the respective neutrino-spheres. In. Pramana – J. ... would be changed to М . One can make a rough estimate of the increase in heating rate assuming the ...

  20. Phenomenology of MaVaN’s Models in Reactor Neutrino Data

    Directory of Open Access Journals (Sweden)

    M. F. Carneiro

    2013-01-01

    Full Text Available Mass Varying Neutrinos (MaVaN’s mechanisms were proposed to link the neutrino mass scale with the dark energy density, addressing the coincidence problem. In some scenarios, this mass can present a dependence on the baryonic density felt by neutrinos, creating an effective neutrino mass that depends both on the neutrino and baryonic densities. In this work, we study the phenomenological consequence of MaVaN’s scenarios in which the matter density dependence is induced by Yukawa interactions of a light neutral scalar particle which couples to neutrinos and matter. Under the assumption of one mass scale dominance, we perform an analysis of KamLAND neutrino data which depends on 4 parameters: the two standard oscillation parameters, Δm0,212 and tan2θ12, and two new coefficients which parameterize the environment dependence of neutrino mass. We introduce an Earth’s crust model to compute precisely the density in each point along the neutrino trajectory. We show that this new description of density does not affect the analysis with the standard model case. With the MaVaN model, we observe a first order effect in lower density, which leads to an improvement on the data description.

  1. Insights into neutrino decoupling gleaned from considerations of the role of electron mass

    Science.gov (United States)

    Grohs, E.; Fuller, George M.

    2017-10-01

    We present calculations showing how electron rest mass influences entropy flow, neutrino decoupling, and Big Bang Nucleosynthesis (BBN) in the early universe. To elucidate this physics and especially the sensitivity of BBN and related epochs to electron mass, we consider a parameter space of rest mass values larger and smaller than the accepted vacuum value. Electromagnetic equilibrium, coupled with the high entropy of the early universe, guarantees that significant numbers of electron-positron pairs are present, and dominate over the number of ionization electrons to temperatures much lower than the vacuum electron rest mass. Scattering between the electrons-positrons and the neutrinos largely controls the flow of entropy from the plasma into the neutrino seas. Moreover, the number density of electron-positron-pair targets can be exponentially sensitive to the effective in-medium electron mass. This entropy flow influences the phasing of scale factor and temperature, the charged current weak-interaction-determined neutron-to-proton ratio, and the spectral distortions in the relic neutrino energy spectra. Our calculations show the sensitivity of the physics of this epoch to three separate effects: finite electron mass, finite-temperature quantum electrodynamic (QED) effects on the plasma equation of state, and Boltzmann neutrino energy transport. The ratio of neutrino to plasma-component energy scales manifests in Cosmic Microwave Background (CMB) observables, namely the baryon density and the radiation energy density, along with the primordial helium and deuterium abundances. Our results demonstrate how the treatment of in-medium electron mass (i.e., QED effects) could translate into an important source of uncertainty in extracting neutrino and beyond-standard-model physics limits from future high-precision CMB data.

  2. Insights into neutrino decoupling gleaned from considerations of the role of electron mass

    Directory of Open Access Journals (Sweden)

    E. Grohs

    2017-10-01

    Full Text Available We present calculations showing how electron rest mass influences entropy flow, neutrino decoupling, and Big Bang Nucleosynthesis (BBN in the early universe. To elucidate this physics and especially the sensitivity of BBN and related epochs to electron mass, we consider a parameter space of rest mass values larger and smaller than the accepted vacuum value. Electromagnetic equilibrium, coupled with the high entropy of the early universe, guarantees that significant numbers of electron–positron pairs are present, and dominate over the number of ionization electrons to temperatures much lower than the vacuum electron rest mass. Scattering between the electrons–positrons and the neutrinos largely controls the flow of entropy from the plasma into the neutrino seas. Moreover, the number density of electron–positron-pair targets can be exponentially sensitive to the effective in-medium electron mass. This entropy flow influences the phasing of scale factor and temperature, the charged current weak-interaction-determined neutron-to-proton ratio, and the spectral distortions in the relic neutrino energy spectra. Our calculations show the sensitivity of the physics of this epoch to three separate effects: finite electron mass, finite-temperature quantum electrodynamic (QED effects on the plasma equation of state, and Boltzmann neutrino energy transport. The ratio of neutrino to plasma–component energy scales manifests in Cosmic Microwave Background (CMB observables, namely the baryon density and the radiation energy density, along with the primordial helium and deuterium abundances. Our results demonstrate how the treatment of in-medium electron mass (i.e., QED effects could translate into an important source of uncertainty in extracting neutrino and beyond-standard-model physics limits from future high-precision CMB data.

  3. Sterile neutrinos with eV masses in cosmology — How disfavoured exactly?

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, G.G.

    2011-01-01

    We study cosmological models that contain sterile neutrinos with eV-range masses as suggested by reactor and short-baseline oscillation data. We confront these models with both precision cosmological data (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch...... be circumvented by a small νe degeneracy. Any model containing eV-mass sterile neutrinos implies also strong modifications of other cosmological parameters. Notably, the inferred cold dark matter density can shift up by 20-75% relative to the standard ΛCDM value....

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

    CERN Document Server

    De Rújula, A

    2013-01-01

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

  5. Fermion masses and mixings in SO(10) (II). Probing grand unification through neutrino oscillations

    Science.gov (United States)

    Lazarides, G.; Shafi, Q.

    In a class of grand unified models based on SO(10), the mixing angles in the lepton sector are related by symmetry arguments to the measured quark mixing angles. The mixing angles relevant in neutrino oscillations are estimated to be sin 22θ cμc ⋍ 0.02 , sin 22θ μτ ⋍ (0.36-1.3) × 10 -2 and sin 2 2 fθc τ } - (0.04-2) × 10 -4. A variety of considerations unrelated to neutrino oscillations enable us to estimate the neutrino masses as well. The heaviest (essentially "tau") neutrino lies in the range 0.5-8 eV, the "muon" neutrino is close to 10 -3 eV, while the "electron" neutrino turns out to be substantially lighter. These predictions can be confronted with recent, ongoing, and proposed neutrino oscillation experiments. As a by-product, one obtains a new understanding of the well-known asymptotic relation mμ = 3 ms.

  6. Neutrinos

    OpenAIRE

    Gouvea, AD; Pitts, K; Scholberg, K; Zeller, GP; Alonso, J; Bernstein, A; Bishai, M; Elliott, S; Heeger, K; Hoffman, K; Huber, P; Kaufman, LJ; Kayser, B; Link, J; Lunardini, C

    2016-01-01

    This document represents the response of the Intensity Frontier Neutrino Working Group to the Snowmass charge. We summarize the current status of neutrino physics and identify many exciting future opportunities for studying the properties of neutrinos and for addressing important physics and astrophysics questions with neutrinos. Report of the Community Summer Study 2013 (Snowmass) Intensity Frontier Neutrino Working Group

  7. Studies on PINGU's sensitivity to the neutrino mass hierarchy

    Energy Technology Data Exchange (ETDEWEB)

    Berghaus, P.; Bretz, H.P.; Shanidze, R. [DESY, D-15738 Zeuthen (Germany); Gross, A.; Leute, J.; Odrowski, S.; Resconi, E. [Technische Universitaet Muenchen, D-85748 Garching (Germany); Kappes, A. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-12489 Berlin (Germany); DESY, D-15738 Zeuthen (Germany)

    2013-07-01

    The determination of the neutrino mass hierarchy is among the most fundamental questions in particle physics. The recent measurement of a large mixing angle between the first and the third neutrino mass eigenstate and the first observation of atmospheric neutrino oscillations at tens of GeV with neutrino telescopes opens the intriguing new possibility to exploit matter effects in neutrino oscillation to determine the mass hierarchy in the neutrino sector. We discuss in this talk the ongoing IceCube/DeepCore activities and the potential of the PINGU extension with a further lowered energy threshold. The status of calculations concerning PINGU's sensitivity to the mass hierarchy is reported.

  8. Implications of neutrino masses and mixing for weak processes

    International Nuclear Information System (INIS)

    Shrock, R.E.

    1981-01-01

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

  9. The S{sub 3} flavour symmetry: Neutrino masses and mixings

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Canales, F. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico); Facultad de Ciencias de la Electronica, Benemerita Universidad Autonoma de Puebla (Mexico); Mondragon, A.; Mondragon, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico)

    2013-04-02

    In this work, we discuss the neutrino masses and mixings as the realization of an S{sub 3} flavour permutational symmetry in two models, namely the Standard Model and an extension of the Standard Model with three Higgs doublets. In the S{sub 3} Standard Model, mass matrices of the same generic form are obtained for the neutrino and charged leptons when the S{sub 3} flavour symmetry is broken sequentially according to the chain S{sub 3L} x S{sub 3R} contains S{sub 3}{sup diag} contains S{sub 2}. In the minimal S{sub 3}-symmetric extension of the Standard Model, the S{sub 3} symmetry is left unbroken, and the concept of flavour is extended to the Higgs sector by introducing in the theory three Higgs fields which are SU(2) doublets. In both models, the mass matrices of the neutrinos and charged leptons are reparametrized in terms of their eigenvalues, and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained. In the case of the S{sub 3} Standard Model, from a {chi}{sup 2} fit of the theoretical expressions of the lepton mixing matrix to the values extracted from experiment, the numerical values of the neutrino mixing angles are obtained in excellent agreement with experimental data. In the S{sub 3} extension of the Standard Model, if two of the right handed neutrinos masses are degenerate, the reactor and atmospheric mixing angles are determined by the masses of the charged leptons, yielding {theta}{sub 23} in excellent agreement with experimental data, and {theta}{sub 13} different from zero but very small. If the masses of the three right handed neutrinos are assumed to be different, then it is possible to get {theta}{sub 13}also in very good agreement with experimental data. We also show the branching ratios of some selected flavour changing neutral currents (FCNC) process as well as the contribution of the exchange of a neutral flavour changing scalar to the anomaly of the

  10. Neutrino Oscillations in Extended Anti-GUT Model

    CERN Document Server

    Froggatt, C.D.; Takanishi, Y.

    2000-10-16

    What we call the Anti-GUT model is extended a bit to include also right-handed neutrinos and thus make use of the see-saw mechanism for neutrino masses. This model consists in assigning gauge quantum numbers to the known Weyl fermions and the three see-saw right-handed neutrinos. Each family (generation) is given its own Standard Model gauge fields and a gauge field coupled to the $B-L$ quantum number for that family alone. Further we assign a rather limited number of Higgs fields, so as to break these gauge groups down to the Standard Model gauge group and to fit, w.r.t. order of magnitude, the spectra and mixing angles of the quarks and leptons. We find a rather good fit, which for neutrino oscillations favours the small mixing angle MSW solution, although the mixing angle predicted is closest to the upper side of the uncertainty range for the measured solar neutrino mixing angle. An idea for making a ``finetuning''-principle to ``explain'' the large ratios found empirically in physics, and answer such ques...

  11. Visible neutrino decay at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

    2017-05-09

    If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

  12. arXiv Neutrino Masses from Outer Space

    CERN Document Server

    D'Amico, Guido; Kaloper, Nemanja

    Neutrinos can gain mass from coupling to an ultralight field in slow roll. When such a field is displaced from its minimum, its vev acts just like the Higgs vev in spontaneous symmetry breaking. Although these masses may eventually vanish, they do it over a very long time. The theory is technically natural, with the ultralight field-dependent part being the right-handed Majorana mass. The mass variation induced by the field correlates with the cosmological evolution. The change of the mass term changes the mixing matrix, and therefore suppresses the fraction of sterile neutrinos at earlier times and increases it at later times. Since the issue of quantum gravity corrections to field theories with large field variations remains open, this framework may give an observational handle on the Weak Gravity Conjecture.

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

    Directory of Open Access Journals (Sweden)

    A. Nucciotti

    2016-01-01

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

  14. Neutrino mass | Nduka | Journal of the Nigerian Association of ...

    African Journals Online (AJOL)

    It turns out that geometrization of matter is a necessary prerequisite for the resolution of many problems of considerable current interest. In this paper we discuss the geometrization of matter, and deduce therefore the mass of the neutrino. Journal of the Nigerian Association of Mathematical Physics Vol. 10 2006: pp. 1-4 ...

  15. Neutrino mass patterns, ¡ -parity violating supersymmetry and ...

    Indian Academy of Sciences (India)

    January 2000 physics pp. 147–154. Neutrino mass patterns, ¡ -parity violating supersymmetry and associated phenomenology. BISWARUP MUKHOPADHYAYA ... Supersymmetry (SUSY) is perhaps the object of the hottest pursuit in terms of physics beyond the ..... [19] D Kaplan and A Nelson, hep-ph/9901254. S Choi et al ...

  16. A common source for neutrino and sparticle masses

    CERN Document Server

    Brignole, Andrea; Rossi, Anna

    2010-01-01

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

  17. Neutrino mass bounds from neutrinoless double beta-decays and ...

    Indian Academy of Sciences (India)

    2016-01-21

    Jan 21, 2016 ... Abstract. We investigate the way the total mass sum of neutrinos can be constrained from the neu- trinoless double beta-decay and cosmological probes with cosmic microwave background (CMBR), large-scale structures including 2dFGRS and SDSS datasets. First we discuss, in brief, the current status of ...

  18. Most recent results of the Mainz Neutrino Mass Espetiment

    Czech Academy of Sciences Publication Activity Database

    Kraus, Ch.; Bornschein, L.; Bonn, J.; Bornschein, B.; Conde, F.; Flatt, B.; Kovalík, Alojz; Müller, B.; Otten, E.; Schall, J.; Thümmler, Th.; Weinheimer, Ch.

    2003-01-01

    Roč. 118, - (2003), s. 482 ISSN 0920-5632 R&D Projects: GA ČR GA202/02/0157 Institutional research plan: CEZ:AV0Z1048901 Keywords : beta-spectrum * neutrino mass Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.990, year: 2003

  19. Meson exchange second class currents and the neutrino mass in the muon capture by light nuclei

    International Nuclear Information System (INIS)

    Katkhat, Ch.L.

    1988-01-01

    Influence of the Kubodera-Delorme-Rho model parameters (ζ and ξ), the scalar form factor (F s ) and the muonic neutrino rest mass (m νμ ) on the asymmetry coefficient (α μν ) of neutrino emission with respect to the muon spin orientation in the muon capture by light nuclei is analyzed. It is shown, that the mass m νμ , the parameters of ζ and ξ, and the form factor F s may be estimated by studying the coefficient α μν in O -> O, Gamov-Teller, and mixed transitions, respectively

  20. Another look at the impact of an eV-mass sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays

    Science.gov (United States)

    Liu, Jun-Hao; Zhou, Shun

    2018-01-01

    The possible existence of an eV-mass sterile neutrino, slightly mixing with ordinary active neutrinos, is not yet excluded by neutrino oscillation experiments. Assuming neutrinos to be Majorana particles, we explore the impact of such a sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays 〈m〉ee‧≡ m 1|V e1|2eiρ + m 2|V e2|2 + m 3|V e3|2eiσ + m 4|V e4|2eiω, where mi and Vei (for i = 1, 2, 3, 4) denote respectively the absolute masses and the first-row elements of the 4 × 4 neutrino flavor mixing matrix V, for which a full parametrization involves three Majorana-type CP-violating phases {ρ,σ,ω}. A zero effective neutrino mass |〈m〉ee‧| = 0 is possible, no matter whether three active neutrinos take the normal or inverted mass ordering, and its implications for the parameter space are examined in great detail. In particular, given the best-fit values of m4 ≈ 1.3eV and |Ve4|2 ≈ 0.019 from the latest global analysis of neutrino oscillation data, a three-dimensional view of |〈m〉ee‧| in the (mlightest,ρ)-plane is presented and further compared with that of the counterpart |〈m〉ee| in the absence of any sterile neutrino.

  1. External meeting: KATRIN - direct measurement of neutrino masses with sub-eV sensitivity

    CERN Multimedia

    2007-01-01

    GENEVA UNIVERSITY - ECOLE DE PHYSIQUE Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 - Tél : 022 379 62 73 - Fax: 022 379 69 92 Wednesday 18 April 2007 PARTICLE PHYSICS SEMINAR at 17:00 - Stückelberg Auditorium KATRIN - direct measurement of neutrino masses with sub-eV sensitivity by Prof. Guido Drexlin, Karlsruhe Institute of Technology KIT The major scientific objective of the international Karlsruhe Tritum Neutrino (KATRIN) Experiment is the model independent measurement of the electron neutrino mass in tritium beta decay with a sensitivity of 200 meV. In the cosmological context, this allows an investigation of whether massive relic neutrinos left over from the Big Bang play a specific role as hot dark matter in the evolution of large scale structures of the universe. In particle physics KATRIN will allow for discrimination between different neutrino mass models (either of quasi-degenerate or hierarchical pattern).The key components of KATRIN comprise...

  2. Neutrinos

    OpenAIRE

    de Gouvea, A.; Pitts, K.; Scholberg, K.; Zeller, G. P.; Alonso, J.; Bernstein, A.; Bishai, M.; Elliott, S.; Heeger, K.; Hoffman, K.; Huber, P.; Kaufman, L. J.; Kayser, B.; Link, J.; Lunardini, C.

    2013-01-01

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

  3. keV right-handed neutrinos from type II seesaw mechanism in a 3-3-1 model

    International Nuclear Information System (INIS)

    Cogollo, D.; Diniz, H.; Pires, C.A. de S

    2009-01-01

    We adapt the type II seesaw mechanism to the framework of the 3-3-1 model with right-handed neutrinos. We emphasize that the mechanism is capable of generating small masses for the left-handed and right-handed neutrinos and the structure of the model allows that both masses arise from the same Yukawa coupling. For typical values of the free parameters of the model we may obtain at least one right-handed neutrino with mass in the keV range. Right-handed neutrino with mass in this range is a viable candidate for the warm component of the dark matter existent in the universe.

  4. From high-scale leptogenesis to low-scale one-loop neutrino mass generation

    Science.gov (United States)

    Zhou, Hang; Gu, Pei-Hong

    2018-02-01

    We show that a high-scale leptogenesis can be consistent with a low-scale one-loop neutrino mass generation. Our models are based on the SU(3)c × SU(2)L × U(1)Y × U(1) B - L gauge groups. Except a complex singlet scalar for the U(1) B - L symmetry breaking, the other new scalars and fermions (one scalar doublet, two or more real scalar singlets/triplets and three right-handed neutrinos) are odd under an unbroken Z2 discrete symmetry. The real scalar decays can produce an asymmetry stored in the new scalar doublet which subsequently decays into the standard model lepton doublets and the right-handed neutrinos. The lepton asymmetry in the standard model leptons then can be partially converted to a baryon asymmetry by the sphaleron processes. By integrating out the heavy scalar singlets/triplets, we can realize an effective theory to radiatively generate the small neutrino masses at the TeV scale. Furthermore, the lightest right-handed neutrino can serve as a dark matter candidate.

  5. Models of light singlet fermion and neutrino phenomenology

    International Nuclear Information System (INIS)

    Chun, E.J.; Joshipura, A.S.; Smirnov, A.Yu.

    1995-05-01

    We suggest that a single fermion S exists beyond the standard see-saw structure. It mixes with light neutrinos via interactions with the right-handed neutrino components, so that ν e → S conversion solves the solar neutrino problem. Supersymmetry endowed with R-symmetry is shown to give a natural framework for existence, mass scale (∼ 3 · 10 -3 eV) and mixing (sin 2 2θ es ∼ (0.1 - 1.5) · 10 -2 ) of such a fermion. Models with an approximate horizontal symmetry are constructed, which embed the fermion S and explain simultaneously solar, atmospheric, hot dark matter problems as well as may predict the oscillation ν-bar μ → ν-bar e in the region of sensitivity of KARMEN and LSND experiments. (author). 24 refs

  6. Repressing anarchy in neutrino mass textures

    Science.gov (United States)

    Altarelli, Guido; Feruglio, Ferruccio; Masina, Isabella; Merlo, Luca

    2012-11-01

    The recent results that θ 13 is relatively large, of the order of the previous upper bound, and the indications of a sizable deviation of θ 23 from the maximal value are in agreement with the predictions of Anarchy in the lepton sector. The quark and charged lepton hierarchies can then be reproduced in a SU(5) GUT context by attributing non-vanishing U(1)FN charges, different for each family, only to the SU(5) tenplet states. The fact that the observed mass hierarchies are stronger for up quarks than for down quarks and charged leptons supports this idea. As discussed in the past, in the flexible context of SU(5) ⊗ U(1)FN, different patterns of charges can be adopted going from Anarchy to various types of hierarchy. We revisit this approach by also considering new models and we compare all versions to the present data. As a result we confirm that, by relaxing the ansatz of equal U(1)FN charges for all SU(5) pentaplets and singlets, better agreement with the data than for Anarchy is obtained without increasing the model complexity. We also present the distributions obtained in the different models for the Dirac CP-violating phase. Finally we discuss the relative merits of these simple models.

  7. Galaxy Formation in Sterile Neutrino Dark Matter Models

    Science.gov (United States)

    Menci, N.; Grazian, A.; Lamastra, A.; Calura, F.; Castellano, M.; Santini, P.

    2018-02-01

    We investigate galaxy formation in models with dark matter (DM) constituted by sterile neutrinos. Given their large parameter space, defined by the combinations of sterile neutrino mass {m}ν and mixing parameter {\\sin }2(2θ ) with active neutrinos, we focus on models with {m}ν =7 {keV}, consistent with the tentative 3.5 keV line detected in several X-ray spectra of clusters and galaxies. We consider (1) two resonant production models with {\\sin }2(2θ )=5 × {10}-11 and {\\sin }2(2θ )=2 × {10}-10, to cover the range of mixing parameters consistent with the 3.5 keV line; (2) two scalar-decay models, representative of the two possible cases characterizing such a scenario: a freeze-in and a freeze-out case. We also consider thermal warm DM with particle mass {m}X=3 {keV}. Using a semianalytic model, we compare the predictions for the different DM scenarios with a wide set of observables. We find that comparing the predicted evolution of the stellar mass function, the abundance of satellites of Milky Way–like galaxies, and the global star formation history of galaxies with observations does not allow us to disentangle the effects of the baryonic physics from those related to the different DM models. On the other hand, the distribution of the stellar-to-halo mass ratios, the abundance of faint galaxies in the UV luminosity function at z≳ 6, and the specific star formation and age distribution of local, low-mass galaxies constitute potential probes for the DM scenarios considered. We discuss how future observations with upcoming facilities will enable us to rule out or to strongly support DM models based on sterile neutrinos.

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

    Energy Technology Data Exchange (ETDEWEB)

    Addazi, Andrea [Dipartimento di Fisica, Università di L' Aquila, 67010 Coppito AQ (Italy); Laboratori Nazionali del Gran Sasso (INFN), 67010 Assergi AQ (Italy); Capozziello, Salvatore [Dipartimento di Fisica “Ettore Pancini”, Università di Napoli “Federico II”, INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); Gran Sasso Science Institute (INFN), Viale F. Crispi 7, I-67100, L' Aquila (Italy); Odintsov, Sergei [Institució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona (Spain); Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Carrer de Can Magrans, s/n 08193 Cerdanyola del Valles, Barcelona (Spain); Lab. Theor. Cosmology, Tomsk State University of Control Systems and Radioelectronics (TUSUR), 634050 Tomsk (Russian Federation); Tomsk State Pedagogical University, 634061 Tomsk (Russian Federation)

    2016-09-10

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

  9. The solar neutrinos epopee

    CERN Document Server

    Lasserre, T

    2003-01-01

    The 2002 year has been fruitful for the neutrino physics. First, the Sudbury Neutrino Observatory (SNO) experiment has shown that the electron neutrinos nu sub e emitted by the sun are converted into muon neutrinos (nu submu) and tau neutrinos (nu subtau), thus closing the 30 years old problem of solar neutrinos deficit. This discovery validates the model of nuclear energy production inside the sun but it shakes the theory describing the weak interactions between the fundamental constituents of matter. This theory considers the neutrinos (and the photons) as massless particles, while the taste conversion phenomenon necessarily implies that neutrinos have a mass. In October 2000, the Universe exploration by the cosmic neutrinos is jointly recognized by R. Davis (USA) and M. Koshiba (Japan) who received the Nobel price of physics. Finally, in December 2000, the KamLAND experiment quantitatively demonstrated the neutrinos metamorphosis by detecting a deficit in the flux of electron antineutrinos coming from the ...

  10. Computation of neutrino masses in R-parity violating supersymmetry: SOFTSUSY3.2

    Science.gov (United States)

    Allanach, B. C.; Kom, C. H.; Hanussek, M.

    2012-03-01

    The program SOFTSUSY can calculate tree-level neutrino masses in the R-parity violating minimal supersymmetric standard model (MSSM) with real couplings. At tree-level, only one neutrino acquires a mass, in contradiction with neutrino oscillation data. Here, we describe an extension to the SOFTSUSY program which includes one-loop R-parity violating effects' contributions to neutrino masses and mixing. Including the one-loop effects refines the radiative electroweak symmetry breaking calculation, and may result in up to three massive, mixed neutrinos. This paper serves as a manual to the neutrino mass prediction mode of the program, detailing the approximations and conventions used. Program summaryProgram title: SOFTSUSY Catalogue identifier: ADPM_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADPM_v3_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 93 291 No. of bytes in distributed program, including test data, etc.: 1 288 618 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on Linux 4.x Word size: 32 bits Classification: 11.1, 11.6 Catalogue identifier of previous version: ADPM_v2_0 Journal reference of previous version: Comput. Phys. Comm. 181 (2010) 232 Does the new version supersede the previous version?: Yes Nature of problem: Calculation of neutrino masses and the neutrino mixing matrix at one-loop level in the R-parity violating minimal supersymmetric standard model. The solution to the renormalisation group equations must be consistent with a high or weak-scale boundary condition on supersymmetry breaking parameters and R-parity violating parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm

  11. Status of Heavy Neutrino Experiments

    CERN Document Server

    Wynne, Benjamin; The ATLAS collaboration

    2017-01-01

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

  12. Changing the Bayesian prior: Absolute neutrino mass constraints in nonlocal gravity*

    Science.gov (United States)

    Dirian, Yves

    2017-10-01

    Prior change is discussed in observational constraints studies of nonlocally modified gravity, where a model characterized by a modification of the form ˜m2R □-2R to the Einstein-Hilbert action was compared against the base Λ CDM one in a Bayesian way. It was found that the competing modified gravity model is significantly disfavored (at 22 ∶1 in terms of betting-odds) against Λ CDM given CMB +SNIa +BAO data, because of a tension appearing in the H0- ΩM plane. We identify the underlying mechanism generating such a tension and show that it is mostly caused by the late-time, quite smooth, phantom nature of the effective dark energy described by the nonlocal model. We find that the tension is resolved by considering an extension of the initial baseline, consisting in allowing the absolute mass of three degenerated massive neutrino species ∑mν/3 to take values within a prior interval consistent with existing data. As a net effect, the absolute neutrino mass is inferred to be nonvanishing at 2 σ level, best-fitting at ∑mν≈0.21 eV , and the Bayesian tension disappears rendering the nonlocal gravity model statistically equivalent to Λ CDM , given recent CMB +SNIa +BAO data. We also discuss constraints from growth rate measurements f σ8, whose fit is found to be improved by a larger massive neutrino fraction as well. The ν -extended nonlocal model also prefers a higher value of H0 than Λ CDM , therefore in better agreement with local measurements. Our study provides one more example suggesting that the neutrino density fraction Ων is partially degenerated with the nature of the dark energy. This emphasizes the importance of cosmological and terrestrial neutrino research and, as a massive neutrino background impacts structure formation observables non-negligibly, proves to be especially relevant for future galaxy surveys.

  13. The nucleon axial mass and the MiniBooNE quasielastic neutrino-nucleus scattering problem

    International Nuclear Information System (INIS)

    Nieves, J.; Ruiz Simo, I.; Vicente Vacas, M.J.

    2012-01-01

    The charged-current double differential neutrino cross section, measured by the MiniBooNE Collaboration, has been analyzed using a microscopical model that accounts for, among other nuclear effects, long range nuclear (RPA) correlations and multinucleon scattering. We find that MiniBooNE data are fully compatible with the world average of the nucleon axial mass in contrast with several previous analyses which have suggested an anomalously large value. We also discuss the reliability of the algorithm used to estimate the neutrino energy.

  14. The physics of neutrinos

    CERN Document Server

    Barger, Vernon D; Whisnant, Kerry

    2012-01-01

    The physics of neutrinos- uncharged elementary particles that are key to helping us better understand the nature of our universe - is one of the most exciting frontiers of modern science. This book provides a comprehensive overview of neutrino physics today and explores promising new avenues of inquiry that could lead to future breakthroughs. The Physics of Neutrinos begins with a concise history of the field and a tutorial on the fundamental properties of neutrinos, and goes on to discuss how the three neutrino types interchange identities as they propagate from their sources to detectors. The book shows how studies of neutrinos produced by such phenomena as cosmic rays in the atmosphere and nuclear reactions in the solar interior provide striking evidence that neutrinos have mass, and it traces our astounding progress in deciphering the baffling experimental findings involving neutrinos. The discovery of neutrino mass offers the first indication of a new kind of physics that goes beyond the Standard Model ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-22

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

  16. Repressing Anarchy in Neutrino Mass Textures

    CERN Document Server

    Altarelli, Guido; Masina, Isabella; Merlo, Luca

    2012-01-01

    The recent results that $\\theta_{13}$ is relatively large, of the order of the previous upper bound, and the indications of a sizable deviation of $\\theta_{23}$ from the maximal value are in agreement with the predictions of Anarchy in the lepton sector. The quark and charged lepton hierarchies can then be reproduced in a SU(5) GUT context by attributing non-vanishing $U(1)_{FN}$ charges, different for each family, only to the SU(5) tenplet states. The fact that the observed mass hierarchies are stronger for up quarks than for down quarks and charged leptons supports this idea. As discussed in the past, in the flexible context of $SU(5)\\otimes U(1)_{FN}$, different patterns of charges can be adopted going from Anarchy to various types of hierarchy. We revisit this approach by also considering new models and we compare all versions to the present data. As a result we confirm that, by relaxing the extreme ansatz of equal $U(1)_{FN}$ charges for all SU(5) pentaplets and singlets, better agreement with the data t...

  17. A natural connection between neutrino mass generation and the ...

    Indian Academy of Sciences (India)

    2012-10-05

    Oct 5, 2012 ... of lepton number violation that also yields an acceptable neutrino mass [3]. In the NMSSM, the lightest CP-odd physical scalar A1 can be decomposed as,. A1 ≡ cos θA AMSSM + sin θA AS ,. (1) where AMSSM is the MSSM part of the CP-odd scalar, which arises solely from the. NMSSM Higgs doublets and ...

  18. Neutrino masses, leptogenesis and dark matter from small lepton number violation?

    Science.gov (United States)

    Abada, Asmaa; Arcadi, Giorgio; Domcke, Valerie; Lucente, Michele

    2017-12-01

    We consider the possibility of simultaneously addressing the baryon asymmetry of the Universe, the dark matter problem and the neutrino mass generation in minimal extensions of the Standard Model via sterile fermions with (small) total lepton number violation. Within the framework of Inverse and Linear Seesaw models, the small lepton number violating parameters set the mass scale of the active neutrinos, the efficiency of leptogenesis through a small mass splitting between pairs of sterile fermions as well as the mass scale of a sterile neutrino dark matter candidate. We provide an improved parametrization of these seesaw models taking into account existing experimental constraints and derive a linearized system of Boltzmann equations to describe the leptogenesis process, which allows for an efficient investigation of the parameter space. This in particular enables us to perform a systematic study of the strong washout regime of leptogenesis. Our study reveals that one can have a successful leptogenesis at the temperature of the electroweak scale through oscillations between two sterile states with a natural origin of the (necessary) strong degeneracy in their mass spectrum. The minimal model however requires a non-standard cosmological history to account for the relic dark matter. Finally, we discuss the prospect for neutrinoless double beta decay and for testing, in future experiments, the values of mass and different active-sterile mixings required for successful leptogenesis.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-03-01

    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.

  20. 170th International School of Physics "Enrico Fermi" : Measurements of Neutrino Mass

    CERN Document Server

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

    2009-01-01

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

  1. Sterile neutrinos in cosmology

    Science.gov (United States)

    Abazajian, Kevork N.

    2017-11-01

    Sterile neutrinos are natural extensions to the standard model of particle physics in neutrino mass generation mechanisms. If they are relatively light, less than approximately 10 keV, they can alter cosmology significantly, from the early Universe to the matter and radiation energy density today. Here, we review the cosmological role such light sterile neutrinos can play from the early Universe, including production of keV-scale sterile neutrinos as dark matter candidates, and dynamics of light eV-scale sterile neutrinos during the weakly-coupled active neutrino era. We review proposed signatures of light sterile neutrinos in cosmic microwave background and large scale structure data. We also discuss keV-scale sterile neutrino dark matter decay signatures in X-ray observations, including recent candidate ∼3.5 keV X-ray line detections consistent with the decay of a ∼7 keV sterile neutrino dark matter particle.

  2. A possible solution of the flavor problem and radiative neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Adulpravitchai, Adisorn

    2010-06-23

    In this thesis, we discuss two important problems of the Standard Model of Particle Physics (SM), namely the flavor problem and the reason for the smallness of neutrino masses. The first one might be related to the origin of non-abelian discrete flavor symmetries. We discuss the possibility of obtaining them from an underlying continuous flavor symmetry, i.e. SU(2) or SU(3) through spontaneous symmetry breaking. Moreover, we investigate their possible origin from an orbifold compactification. We discuss all non-abelian discrete symmetries, which can arise from an orbifold T{sup 2}/Z{sub N}. They are A{sub 4}, S{sub 4}, D{sub 4}, D{sub 3}, and D{sub 6}. We present the idea of combining the breaking of an orbifold GUT and the flavor symmetry arising from the orbifold. We demonstrate the construction in a 6d SUSY SO(10) x S{sub 4}. For the second problem, we propose a one-loop neutrino mass model in the left-right symmetric framework. We observe the transmitted hierarchy from the charged lepton masses to the right-handed neutrino masses, which we call ''Radiative Transmission of Lepton Flavor Hierarchy''. Finally, we study the phenomenological aspects of the model such as lepton flavor violation (LFV), flavor number violation (FNV), and flavor changing neutral currents (FCNCs). (orig.)

  3. Astrophysical neutrinos flavored with beyond the Standard Model physics

    International Nuclear Information System (INIS)

    Rasmussen, Rasmus W.; Ackermann, Markus; Winter, Walter; Lechner, Lukas; Kowalski, Marek; Humboldt-Universitaet, Berlin

    2017-07-01

    We systematically study the allowed parameter space for the flavor composition of astrophysical neutrinos measured at Earth, including beyond the Standard Model theories at production, during propagation, and at detection. One motivation is to illustrate the discrimination power of the next-generation neutrino telescopes such as IceCube-Gen2. We identify several examples that lead to potential deviations from the standard neutrino mixing expectation such as significant sterile neutrino production at the source, effective operators modifying the neutrino propagation at high energies, dark matter interactions in neutrino propagation, or non-standard interactions in Earth matter. IceCube-Gen2 can exclude about 90% of the allowed parameter space in these cases, and hence will allow to efficiently test and discriminate models. More detailed information can be obtained from additional observables such as the energy-dependence of the effect, fraction of electron antineutrinos at the Glashow resonance, or number of tau neutrino events.

  4. Astrophysical neutrinos flavored with beyond the Standard Model physics

    Science.gov (United States)

    Rasmussen, Rasmus W.; Lechner, Lukas; Ackermann, Markus; Kowalski, Marek; Winter, Walter

    2017-10-01

    We systematically study the allowed parameter space for the flavor composition of astrophysical neutrinos measured at Earth, including beyond the Standard Model theories at production, during propagation, and at detection. One motivation is to illustrate the discrimination power of the next-generation neutrino telescopes such as IceCube-Gen2. We identify several examples that lead to potential deviations from the standard neutrino mixing expectation such as significant sterile neutrino production at the source, effective operators modifying the neutrino propagation at high energies, dark matter interactions in neutrino propagation, or nonstandard interactions in Earth matter. IceCube-Gen2 can exclude about 90% of the allowed parameter space in these cases, and hence will allow us to efficiently test and discriminate between models. More detailed information can be obtained from additional observables such as the energy dependence of the effect, fraction of electron antineutrinos at the Glashow resonance, or number of tau neutrino events.

  5. Final scientific and technical report: New experiments to measure the neutrino mass scale

    Energy Technology Data Exchange (ETDEWEB)

    Monreal, Benjamin [Univ. of California, Santa Barbara, CA (United States)

    2016-11-19

    In this work, we made material progress towards future measurements of the mass of the neutrino. The neutrino is a fundamental particle, first observed in the 1950s and subjected to particularly intense study over the past 20 years. It is now known to have some, non-zero mass, but we are in an unusual situation of knowing the mass exists but not knowing what value it takes. The mass may be determined by precise measurements of certain radioactive decay distributions, particularly the beta decay of tritium. The KATRIN experiment is an international project which is nearing the beginning of a tritium measurement campaign using a large electrostatic spectrumeter. This research included participation in KATRIN, including construction and delivery of a key calibration subsystem, the ``Rear Section''. To obtain sensitivity beyond KATRIN's, new techniques are required; this work included R&D on a new technique we call CRES (Cyclotron Resonance Electron Spectroscopy) which has promise to enable even more sensitive tritium decay measurements. We successfully carried out CRES spectroscopy in a model system in 2014, making an important step towards the design of a next-generation tritium experiment with new neutrino mass measurement abilities.

  6. Constraining neutrino mass and extra relativistic degrees of freedom in dynamical dark energy models using Planck 2015 data in combination with low-redshift cosmological probes: basic extensions to ΛCDM cosmology

    Science.gov (United States)

    Zhao, Ming-Ming; Li, Yun-He; Zhang, Jing-Fei; Zhang, Xin

    2017-08-01

    We investigate how the properties of dark energy affect the cosmological measurements of neutrino mass and extra relativistic degrees of freedom. We limit ourselves to the most basic extensions of Λ cold dark matter (CDM) model, I.e. the wCDM model with one additional parameter w, and the w0waCDM model with two additional parameters, w0 and wa. In the cosmological fits, we employ the 2015 cosmic microwave background temperature and polarization data from the Planck mission, in combination with low-redshift measurements such as the baryon acoustic oscillations, Type Ia supernovae and the Hubble constant (H0). Given effects of massive neutrinos on large-scale structure, we further include weak lensing, redshift space distortion, Sunyaev-Zeldovich cluster counts and Planck lensing data. We show that, though the cosmological constant Λ is still consistent with the current data, a phantom dark energy (w -1) is slightly more favoured by current observations, which leads to the fact that in both wCDM and w0waCDM models we obtain a larger upper limit of ∑mν. We also show that in the three dark energy models, the constraints on Neff are in good accordance with each other, all in favour of the standard value 3.046, which indicates that the dark energy parameters almost have no impact on constraining Neff. Therefore, we conclude that the dark energy parameters can exert a significant influence on the cosmological weighing of neutrinos, but almost cannot affect the constraint on dark radiation.

  7. COSMOGENIC NEUTRINOS CHALLENGE THE COSMIC-RAY PROTON DIP MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Heinze, Jonas; Boncioli, Denise; Winter, Walter [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, D-15738 Zeuthen (Germany); Bustamante, Mauricio, E-mail: jonas.heinze@desy.de, E-mail: denise.boncioli@desy.de, E-mail: walter.winter@desy.de, E-mail: bustamanteramirez.1@osu.edu [Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, OH 43210 (United States)

    2016-07-10

    The origin and composition of ultra-high-energy cosmic rays (UHECRs) remain a mystery. The proton dip model describes their spectral shape in the energy range above 10{sup 9} GeV by pair production and photohadronic interactions with the cosmic microwave background. The photohadronic interactions also produce cosmogenic neutrinos peaking around 10{sup 9} GeV. We test whether this model is still viable in light of recent UHECR spectrum measurements from the Telescope Array experiment and upper limits on the cosmogenic neutrino flux from IceCube. While two-parameter fits have been already presented, we perform a full scan of the three main physical model parameters: source redshift evolution, injected proton maximal energy, and spectral index. We find qualitatively different conclusions compared to earlier two-parameter fits in the literature: a mild preference for a maximal energy cutoff at the sources instead of the Greisen–Zatsepin–Kuzmin cutoff, hard injection spectra, and strong source evolution. The predicted cosmogenic neutrino flux exceeds the IceCube limit for any parameter combination. As a result, the proton dip model is challenged at more than 95% C.L. This is strong evidence against this model independent of mass composition measurements.

  8. Cosmogenic Neutrinos Challenge the Cosmic-ray Proton Dip Model

    Science.gov (United States)

    Heinze, Jonas; Boncioli, Denise; Bustamante, Mauricio; Winter, Walter

    2016-07-01

    The origin and composition of ultra-high-energy cosmic rays (UHECRs) remain a mystery. The proton dip model describes their spectral shape in the energy range above 109 GeV by pair production and photohadronic interactions with the cosmic microwave background. The photohadronic interactions also produce cosmogenic neutrinos peaking around 109 GeV. We test whether this model is still viable in light of recent UHECR spectrum measurements from the Telescope Array experiment and upper limits on the cosmogenic neutrino flux from IceCube. While two-parameter fits have been already presented, we perform a full scan of the three main physical model parameters: source redshift evolution, injected proton maximal energy, and spectral index. We find qualitatively different conclusions compared to earlier two-parameter fits in the literature: a mild preference for a maximal energy cutoff at the sources instead of the Greisen-Zatsepin-Kuzmin cutoff, hard injection spectra, and strong source evolution. The predicted cosmogenic neutrino flux exceeds the IceCube limit for any parameter combination. As a result, the proton dip model is challenged at more than 95% C.L. This is strong evidence against this model independent of mass composition measurements.

  9. Minimal flavour violation and neutrino masses without R-parity

    DEFF Research Database (Denmark)

    Arcadi, G.; Di Luzio, L.; Nardecchia, M.

    2012-01-01

    symmetry breaking all the couplings of the superpotential including the R-parity violating ones. If R-parity violation is responsible for neutrino masses, our setup can be seen as an extension of MFV to the lepton sector. We analyze two patterns based on the non-abelian flavour symmetries SU(3)(4) circle...... times SU(4) and SU(3)(5). In the former case the total lepton number and the lepton flavour number are broken together, while in the latter the lepton number can be broken independently by an abelian spurion, so that visible effects and peculiar correlations can be envisaged in flavour changing charged...

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

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, N.G. [ed.

    1997-12-31

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

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

    International Nuclear Information System (INIS)

    Cooper, N.G.

    1997-01-01

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

  12. Neutrino masses and mixing: a flavour symmetry roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Morisi, S.; Valle, J.W.F. [AHEP Group, Instituto de Fisica Corpuscular - C.S.I.C./Universitat de Valencia, Edificio de Institutos de Paterna, Apartado 22085, 46071 Valencia (Spain)

    2013-04-02

    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. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. SOX - Towards the detection of sterile neutrinos in Borexino. Beta spectrum modeling, Monte Carlo development and sensitivity studies for the sterile neutrino search in Borexino

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Mikko

    2016-12-15

    Several experiments have reported anomalies in the neutrino sector which might be explained by the existence of a fourth (sterile) neutrino with a squared mass difference of about 1 eV{sup 2} to the other three active neutrinos. The SOX project is part of the experimental program of the Borexino experiment and seeks for a clarification of the observed anomalies. For that purpose an artificial antineutrino source ({sup 144}Ce-{sup 144}Pr) and possibly neutrino source ({sup 51}Cr) will be deployed underneath the large low background detector Borexino. The detector provides both energy and vertex resolution to observe a possible oscillation signature within the detector volume. The calculation of the antineutrino spectrum is based on existing theoretical models and was performed within this thesis. The modeling includes several sub-leading corrections particularly such as finite size of the nucleus, screening of the atomic electrons and radiative effects. Related to this work, dedicated Monte Carlo generators have been developed to simulate the inverse beta decay reaction and the (anti)neutrino elastic scattering off electrons. Based on a profile likelihood analysis, the sensitivity to the sterile neutrino search of the SOX project was evaluated. The results obtained from this analysis confirm that the currently allowed parameter regions for sterile neutrinos can be tested at 95% confidence level. Finally, an alternative concept for the sterile neutrino search is presented which is based on a cyclotron and a Beryllium target near Borexino (Borexino+IsoDAR).

  14. SOX - Towards the detection of sterile neutrinos in Borexino. Beta spectrum modeling, Monte Carlo development and sensitivity studies for the sterile neutrino search in Borexino

    International Nuclear Information System (INIS)

    Meyer, Mikko

    2016-12-01

    Several experiments have reported anomalies in the neutrino sector which might be explained by the existence of a fourth (sterile) neutrino with a squared mass difference of about 1 eV 2 to the other three active neutrinos. The SOX project is part of the experimental program of the Borexino experiment and seeks for a clarification of the observed anomalies. For that purpose an artificial antineutrino source ( 144 Ce- 144 Pr) and possibly neutrino source ( 51 Cr) will be deployed underneath the large low background detector Borexino. The detector provides both energy and vertex resolution to observe a possible oscillation signature within the detector volume. The calculation of the antineutrino spectrum is based on existing theoretical models and was performed within this thesis. The modeling includes several sub-leading corrections particularly such as finite size of the nucleus, screening of the atomic electrons and radiative effects. Related to this work, dedicated Monte Carlo generators have been developed to simulate the inverse beta decay reaction and the (anti)neutrino elastic scattering off electrons. Based on a profile likelihood analysis, the sensitivity to the sterile neutrino search of the SOX project was evaluated. The results obtained from this analysis confirm that the currently allowed parameter regions for sterile neutrinos can be tested at 95% confidence level. Finally, an alternative concept for the sterile neutrino search is presented which is based on a cyclotron and a Beryllium target near Borexino (Borexino+IsoDAR).

  15. Double beta decay and majorana neutrinos. Right-handed currents or nonzero masses

    International Nuclear Information System (INIS)

    Rosen, S.P.; Perlmutter, A.

    1981-01-01

    This chapter describes some new developments concerning the mechanism for lepton number nonconservation in no-neutrino double beta decay. Explains that lepton number nonconservation in no-neutrino double beta decay comes about either because both left- and right-handed components of a Majorano neutrino are coupled to the electron in the weak leptonic current, or because the neutrino has nonzero mass. Shows that while nuclear ground-state to ground-state transitions arise from right-handed currents and from neutrino mass terms, transitions to low-lying excited states with J /SUP P/ =2 + can arise only from right-handed currents. Emphasizes that the possibilities of detecting small admixtures of right-handed currents, and of setting limits on neutrino masses that are either very small or very large, make double beta decay a most rewarding phenomenon to study

  16. Theoretical Models of Neutrino Mixing Recent Developments

    CERN Document Server

    Altarelli, Guido

    2009-01-01

    The data on neutrino mixing are at present compatible with Tri-Bimaximal (TB) mixing. If one takes this indication seriously then the models that lead to TB mixing in first approximation are particularly interesting and A4 models are prominent in this list. However, the agreement of TB mixing with the data could still be an accident. We discuss a recent model based on S4 where Bimaximal mixing is instead valid at leading order and the large corrections needed to reproduce the data arise from the diagonalization of charged leptons. The value of $\\theta_{13}$ could distinguish between the two alternatives.

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

    International Nuclear Information System (INIS)

    Bilenky, S.

    2016-01-01

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

  18. Introduction to the physics of massive and mixed neutrinos

    CERN Document Server

    Bilenky, Samoil

    2018-01-01

    Small neutrino masses are the first signs of new physics beyond the Standard Model of particle physics. Since the first edition of this textbook appeared in 2010, the Nobel Prize has been awarded "for the discovery of neutrino oscillations, which shows that neutrinos have mass". The measurement of the small neutrino mixing angle $\\theta_{13}$ in 2012, launched the precision stage of the investigation of neutrino oscillations. This measurement now allows such fundamental problems as the three-neutrino mass spectrum - is it normal or inverted? – and the $CP$ violation in the lepton sector to be tackled. In order to understand the origin of small neutrino masses, it remains crucial to reveal the nature of neutrinos with definite masses: are they Dirac neutrinos possessing a conserved lepton number, which distinguishes neutrinos and antineutrinos, or are they Majorana neutrinos with identical neutrinos and antineutrinos? Experiments searching for the neutrinoless double beta decay are presently under way to ans...

  19. Neutrinos (1/3)

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    The neutrino, the lightest and most weakly interacting particle of the Standard Model has revealed itself as the messenger of very exciting news in particle physics: there is Physics Beyond the Standard Model. All this thanks to the quantum-mechanical phenomenon of flavour oscillations which is intrinsically connected to the question of neutrino mass and which has been observed in neutrinos produced in natural sources, like the Sun and the Earth's atmosphere, as well as with human made neutrino beams at accelerator and reactors. The purpose of these lectures is to overview some aspects of the phenomenology of massive neutrinos. I will present the simplest extensions for adding neutrino masses to the SM, and then I will describe the phenomenology associated with neutrino oscillations in vacuum and in matter and its present signatures.

  20. Neutrinos

    OpenAIRE

    Ferdinando Casolaro; Alberto Trotta

    2014-01-01

    The article made a survey on neutrinos and the role they have for the understanding of nature, both on a microscopic and cosmic scale.   I neutrini Nell'articolo viene fatta una rassegna sui  neutrini e sul ruolo che essi hanno per la comprensione della natura, sia su scala microscopica, che su scala cosmica. Parole Chiave: neutrino, massa, onde gravitazionali

  1. Neutrinos

    Directory of Open Access Journals (Sweden)

    Ferdinando Casolaro

    2014-12-01

    Full Text Available The article made a survey on neutrinos and the role they have for the understanding of nature, both on a microscopic and cosmic scale.   I neutrini Nell'articolo viene fatta una rassegna sui  neutrini e sul ruolo che essi hanno per la comprensione della natura, sia su scala microscopica, che su scala cosmica. Parole Chiave: neutrino, massa, onde gravitazionali

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

    Directory of Open Access Journals (Sweden)

    Yong Tang

    2015-11-01

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

  3. Constraints on the electron-neutrino mass from the supernova data

    International Nuclear Information System (INIS)

    Abbott, L.F.; Walker, T.P.

    1988-01-01

    The energy versus time of arrival pattern of neutrinos from SN1987A is sensitive to a neutrino mass, m ν , of order a few eV. To disentangle constraints on m ν , from the data, a theory of supernova emission is necessary. We recall the present status of this theory and approximate its predictions in two diffusion models: One designed to reflect the present supernova lore, the other devised to pessimize, within reason, the consequent upper limits on m ν . We discuss the model dependence and statistical significance of our results, as well as the experimental uncertainties and caveats to which they are subject. We adress the question, do the supernova results supercede the present laboratory limits on m ν ? (orig.)

  4. Light Sterile Neutrinos from Large Extra Dimensions

    OpenAIRE

    Ma, Ernest; Rajasekaran, G.; Sarkar, Utpal

    2000-01-01

    An experimentally verifiable Higgs-triplet model of neutrino masses from large extra dimensions was recently proposed. We extend it to accomodate a light sterile neutrino which also mixes with the three active neutrinos. A previously proposed phenomenological model of four neutrinos (\\underline {the only viable such model now left}, in view of the latest atmospheric and solar neutrino-oscillation data) is specifically realized.

  5. The Progenitor-Remnant Connection of Neutrino-Driven Supernovae Across the Stellar Mass Range

    Science.gov (United States)

    Ertl, Thomas

    2017-11-01

    We perform hydrodynamic supernova (SN) simulations in spherical symmetry for progenitor models with solar metallicity across the stellar mass range from 9.0 to 120 M ⊙ to explore the progenitor-explosion and progenitor-remnant connections based on the neutrino-driven mechanism. We use an approximative treatment of neutrino transport and replace the high-density interior of the neutron star (NS) by an inner boundary condition based on an analytic proto-NS core-cooling model, whose free parameters are chosen to reproduce the observables of SN 1987A and the Crab SN for theoretical models of their progenitor stars. Judging the fate of a massive star, either a neutron star (NS) or a black hole (BH), solely by its structure prior to collapse has been ambiguous. Our work and previous attempts find a non-monotonic variation of successful and failed supernovae with zero-age main-sequence mass. We identify two parameters based on the ``critical luminosity'' concept for neutrino-driven explosions, which in combination allows for a clear separation of exploding and non-exploding cases. Continuing our simulations beyond shock break-out, we are able to determine nucleosynthesis, light curves, explosion energies, and remnant masses. The resulting NS initial mass function has a mean gravitational mass near 1.4 M ⊙. The average BH mass is about 9 M ⊙ if only the helium core implodes, and 14 M ⊙ if the entire pre-SN star collapses. Only ~10% of SNe come from stars over 20 M ⊙, and some of these are Type Ib or Ic.

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

    International Nuclear Information System (INIS)

    Yasumi, Shinjiro; Maezawa, Hideki

    1996-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-06

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

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

    Science.gov (United States)

    Farzan, Yasaman

    2015-05-01

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

  9. A 3-3-1 model with right-handed neutrinos based on the Δ (27) family symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.E.C. [Universidad Tecnica Federico Santa Maria and Centro Cienti fico-Tecnologico de Valparaiso, Valparaiso (Chile); Long, H.N. [Vietnam Academy of Science and Technology, Institute of Physics, Hanoi (Viet Nam); Vien, V.V. [Duy Tan University, Institute of Research and Development, Da Nang City (Viet Nam); Tay Nguyen University, Department of Physics, Buon Ma Thuot, DakLak (Viet Nam)

    2016-05-15

    We present the first multiscalar singlet extension of the original 3-3-1 model with right-handed neutrinos, based on the Δ (27) family symmetry, supplemented by the Z{sub 4} x Z{sub 8} x Z{sub 14} flavor group, consistent with current low energy fermion flavor data. In the model under consideration, the light active neutrino masses are generated from a double seesaw mechanism and the observed pattern of charged fermion masses and quark mixing angles is caused by the breaking of the Δ (27) x Z{sub 4} x Z{sub 8} x Z{sub 14} discrete group at very high energy. Our model has only 14 effective free parameters, which are fitted to reproduce the experimental values of the 18 physical observables in the quark and lepton sectors. The obtained physical observables for the quark sector agree with their experimental values, whereas those for the lepton sector also do, only for the inverted neutrino mass hierarchy. The normal neutrino mass hierarchy scenario of the model is disfavored by the neutrino oscillation experimental data. We find an effective Majorana neutrino mass parameter of neutrinoless double beta decay of m{sub ββ} = 22 meV, a leptonic Dirac CP violating phase of 34 {sup circle}, and a Jarlskog invariant of about 10{sup -2} for the inverted neutrino mass spectrum. (orig.)

  10. The Flavour Hierarchy and See-Saw Neutrinos from Bulk Masses in 5d Orbifold GUTs

    CERN Document Server

    Hebecker, A; Hebecker, Arthur; March-Russell, John

    2002-01-01

    In supersymmetric grand unified theories (GUTs) based on S^1/(Z_2 x Z'_2) orbifold constructions in 5 dimensions, Standard Model (SM) matter and Higgs fields can be realized in terms of 5d hypermultiplets. These hypermultiplets can naturally have large bulk masses, leading to a localization of the zero modes at one of the two branes or to an exponential suppression of the mass of the lowest-lying non-zero mode. We demonstrate that these dynamical features allow for the construction of an elegant 3-generation SU(5) model in 5 dimensions that explains all the hierarchies between fermion masses and CKM matrix elements in geometrical terms. Moreover, if U(1)_\\chi (where SU(5) x U(1)_\\chi \\subset SO(10)) is gauged in the bulk, but broken by the orbifold action at the SM brane, the right-handed neutrino mass scale is naturally suppressed relative to M_GUT. Together with our construction in the charged fermion sector this leads, via the usual see-saw mechanism, to a realistic light neutrino mass scale and large neut...

  11. Neutrinos: Fast & Curious

    CERN Document Server

    Barenboim, Gabriela

    2016-01-01

    The Standard Model has been effective way beyond expectations in foreseeing the result of almost all the experimental tests done up so far. In it, neutrinos are massless. Nonetheless, in recent years we have collected solid proofs indicating little but non zero masses for the neutrinos (when contrasted with those of the charged leptons). These masses permit neutrinos to change their flavor and oscillate, indeed a unique treat. In these lectures, I discuss the properties and the amazing potential of neutrinos in and beyond the Standard Model.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, Shinjiro; Maezawa, Hideki [eds.

    1996-02-01

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

  13. Discrete Symmetries and Neutrino Mass Perturbations for θ$_{13}$

    CERN Document Server

    Hall, L J

    2013-01-01

    The recent measurement of the third lepton mixing angle, \\theta_{13}, has shown that, although small compared to \\theta_{12} and \\theta_{23}, it is much larger than anticipated in schemes that generate Tri-Bi-Maximal (TBM) or Golden Ratio (GR) mixing. We develop a model-independent formalism for perturbations away from exact TBM or GR mixing in the neutrino sector. Each resulting perturbation scheme reflects an underlying symmetry structure and involves a single complex parameter. We show that such perturbations can readily fit the observed value of \\theta_{13}, which is then correlated with a change in the other mixing angles. We also determine the implication for the lepton CP violating phases. For comparison we determine the predictions for Bi-Maximal mixing corrected by charged lepton mixing and we discuss the accuracy that will be needed to distinguish between the various schemes.

  14. Neutrino mass patterns,¡-parity violating supersymmetry and ...

    Indian Academy of Sciences (India)

    Motivated by the recent super-Kamiokande results on atmospheric neutrinos, we incorporate massive neutrinos, with large angle oscillation between the second and third generations, in a theory with -parity violating supersymmetry. The general features of such a theory are briefly reviewed. We emphasize its testability ...

  15. Constraint on neutrino masses from SDSS-III/BOSS Ly$\\alpha$ forest and other cosmological probes

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Lesgourgues, Julien; Rossi, Graziano; Borde, Arnaud; Viel, Matteo; Aubourg, Eric; Kirkby, David; LeGoff, Jean-Marc; Rich, James; Roe, Natalie; Ross, Nicholas P.; Schneider, Donald P.; Weinberg, David

    2015-02-27

    We present constraints on the parameters of the $\\Lambda$CDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly$\\alpha$ forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS) by Palanque-Delabrouille et al. (2013), complemented by additional cosmological probes. The interpretation of the measured Ly$\\alpha$ spectrum is done using a second-order Taylor expansion of the simulated power spectrum. BOSS Ly$\\alpha$ data alone provide better bounds than previous Ly$\\alpha$ results, but are still poorly constraining, especially for the sum of neutrino masses $\\sum m_\

  16. Signature of heavy sterile neutrinos at CEPC

    Science.gov (United States)

    Liao, Wei; Wu, Xiao-Hong

    2018-03-01

    We study the production of heavy sterile neutrino N , e+e-→N ν (ν ¯), at the Circular Electron Positron Collider (CEPC) and its l j j signal in its decay to three charged fermions. We study background events for this process which are mainly events coming from W pair production. We study the production of a single heavy sterile neutrino and the sensitivity of CEPC to the mixing of the sterile neutrino with active neutrinos. We study the production of two degenerate heavy sterile neutrinos in a low energy seesaw model by taking into account the constraints on mixings of sterile neutrinos from the neutrinoless double β decay experiment and the masses and mixings of active neutrinos. We show that CEPC under proposal has a good sensitivity to the mixing of sterile neutrinos with active neutrinos for a mass of a sterile neutrino around 100 GeV.

  17. An S 4 model inspired from self-complementary neutrino mixing

    Science.gov (United States)

    Zhang, Xinyi

    2018-03-01

    We build an S 4 model for neutrino masses and mixings based on the self-complementary (SC) neutrino mixing pattern. The SC mixing is constructed from the self-complementarity relation plus {δ }CP}=-\\tfrac{π }{2}. We elaborately construct the model at a percent level of accuracy to reproduce the structure given by the SC mixing. After performing a numerical study on the model’s parameter space, we find that in the case of normal ordering, the model can give predictions on the observables that are compatible with their 3σ ranges, and give predictions for the not-yet observed quantities like the lightest neutrino mass m 1 ∈ [0.003, 0.010] eV and the Dirac CP violating phase {δ }CP}\\in [256.72^\\circ ,283.33^\\circ ].

  18. Neutrino cosmology

    International Nuclear Information System (INIS)

    Berstein, J.

    1984-01-01

    These lectures offer a self-contained review of the role of neutrinos in cosmology. The first part deals with the question 'What is a neutrino.' and describes in a historical context the theoretical ideas and experimental discoveries related to the different types of neutrinos and their properties. The basic differences between the Dirac neutrino and the Majorana neutrino are pointed out and the evidence for different neutrino 'flavours', neutrino mass, and neutrino oscillations is discussed. The second part summarizes current views on cosmology, particularly as they are affected by recent theoretical and experimental advances in high-energy particle physics. Finally, the close relationship between neutrino physics and cosmology is brought out in more detail, to show how cosmological constraints can limit the various theoretical possibilities for neutrinos and, more particularly, how increasing knowledge of neutrino properties can contribute to our understanding of the origin, history, and future of the Universe. The level is that of the beginning graduate student. (orig.)

  19. Measuring the neutrino mass hierarchy with the future KM3NeT/ORCA detector

    Energy Technology Data Exchange (ETDEWEB)

    Hofestaedt, Jannik

    2017-02-22

    The neutrino mass hierarchy can be determined by measuring the energy- and zenith-angle-dependent oscillation pattern of few-GeV atmospheric neutrinos that have traversed the Earth. This measurement is the main science goal of KM3NeT/ORCA ('Oscillation Research with Cosmics in the Abyss'), a planned multi-megaton underwater Cherenkov detector in the Mediterranean Sea. A key task is the reconstruction of shower-like events induced by electron neutrinos in charged-current interactions, which substantially affect the neutrino mass hierarchy sensitivity. In this thesis, numerous aspects of the expected neutrino detection performance of the planned ORCA detector are investigated. A new reconstruction algorithm for neutrino-induced shower-like events is developed. Excellent reconstruction accuracies are achieved, with a neutrino energy resolution better than 26%/24%, and a median neutrino direction resolution better than 11 /9 for electron neutrinos/antineutrinos in charged-current interactions with energies above 7 GeV. It is shown that these resolutions are close to the reconstruction accuracy limits imposed by intrinsic fluctuations in the Cherenkov light signatures. These intrinsic resolution limits are based on generic assumptions about event reconstruction in Cherenkov detectors and are derived as part of this thesis. Differences in event reconstruction capabilities between water- and ice-based Cherenkov detectors are discussed. The configuration of existing trigger algorithms is optimised for the ORCA detector. Based on the developed shower reconstruction, a detector optimisation study of the photosensor density is performed. In addition, it is shown that optical background noise in the deep Mediterranean Sea is not expected to compromise the feasibility of the neutrino mass hierarchy measurement with ORCA. Together, these investigations contribute significantly to the estimated neutrino mass hierarchy sensitivity of ORCA published in the 'Letter of

  20. Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effects

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Atri [Department of Physics, University of Arizona,1118 E. 4th St. Tucson, AZ 85704 (United States); Space sciences, Technologies and Astrophysics Research (STAR) Institute,Université de Liège,Bât. B5a, 4000 Liège (Belgium); Enberg, Rikard [Department of Physics and Astronomy, Uppsala University,Box 516, SE-75120 Uppsala (Sweden); Jeong, Yu Seon [Department of Physics and IPAP, Yonsei University,50 Yonsei-ro Seodaemun-gu, Seoul 03722 (Korea, Republic of); National Institute of Supercomputing and Networking, KISTI,245 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Kim, C.S. [Department of Physics and IPAP, Yonsei University,50 Yonsei-ro Seodaemun-gu, Seoul 03722 (Korea, Republic of); Reno, Mary Hall [Department of Physics and Astronomy, University of Iowa,Iowa City, Iowa 52242 (United States); Sarcevic, Ina [Department of Physics, University of Arizona,1118 E. 4th St. Tucson, AZ 85704 (United States); Department of Astronomy, University of Arizona,933 N. Cherry Ave., Tucson, AZ 85721 (United States); Stasto, Anna [Department of Physics, 104 Davey Lab, The Pennsylvania State University,University Park, PA 16802 (United States)

    2016-11-28

    We evaluate the prompt atmospheric neutrino flux at high energies using three different frameworks for calculating the heavy quark production cross section in QCD: NLO perturbative QCD, k{sub T} factorization including low-x resummation, and the dipole model including parton saturation. We use QCD parameters, the value for the charm quark mass and the range for the factorization and renormalization scales that provide the best description of the total charm cross section measured at fixed target experiments, at RHIC and at LHC. Using these parameters we calculate differential cross sections for charm and bottom production and compare with the latest data on forward charm meson production from LHCb at 7 TeV and at 13 TeV, finding good agreement with the data. In addition, we investigate the role of nuclear shadowing by including nuclear parton distribution functions (PDF) for the target air nucleus using two different nuclear PDF schemes. Depending on the scheme used, we find the reduction of the flux due to nuclear effects varies from 10% to 50% at the highest energies. Finally, we compare our results with the IceCube limit on the prompt neutrino flux, which is already providing valuable information about some of the QCD models.

  1. Atmospheric neutrinos and discovery of neutrino oscillations.

    Science.gov (United States)

    Kajita, Takaaki

    2010-01-01

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

  2. Sudbury neutrino observatory proposal

    International Nuclear Information System (INIS)

    Ewan, G.T.; Evans, H.C.; Lee, H.W.

    1987-10-01

    This report is a proposal by the Sudbury Neutrino Observatory (SNO) collaboration to develop a world class laboratory for neutrino astrophysics. This observatory would contain a large volume heavy water detector which would have the potential to measure both the electron-neutrino flux from the sun and the total solar neutrino flux independent of neutrino type. It will therefore be possible to test models of solar energy generation and, independently, to search for neutrino oscillations with a sensitivity many orders of magnitude greater than that of terrestrial experiments. It will also be possible to search for spectral distortion produced by neutrino oscillations in the dense matter of the sun. Finally the proposed detector would be sensitive to neutrinos from a stellar collapse and would detect neutrinos of all types thus providing detailed information on the masses of muon- and tau-neutrinos. The neutrino detector would contain 1000 tons of D20 and would be located more than 2000 m below ground in the Creighton mine near Sudbury. The operation and performance of the proposed detector are described and the laboratory design is presented. Construction schedules and responsibilities and the planned program of technical studies by the SNO collaboration are outlined. Finally, the total capital cost is estimated to be $35M Canadian and the annual operating cost, after construction, would be $1.8 M Canadian, including the insurance costs of the heavy water

  3. Probing dark matter models with neutrinos from the Galactic center

    OpenAIRE

    Erkoca, Arif Emre; Reno, Mary Hall; Sarcevic, Ina

    2010-01-01

    We calculate the contained and upward muon and shower fluxes due to neutrinos produced via dark matter annihilation or decay in the Galactic center. We consider dark matter models in which the dark matter particle is a gravitino, a Kaluza-Klein particle and a particle in leptophilic models. The Navarro-Frenk-White profile for the dark matter density distribution in the Galaxy is used. We incorporate neutrino oscillations by assuming maximal mixing and parametrize our results for muon and show...

  4. Neutrino fluxes from nonuniversal Higgs mass LSP annihilations in the Sun

    CERN Document Server

    Ellis, John; Savage, Christopher; Spanos, Vassilis C.; 10.1103/PhysRevD.83.085023

    2011-01-01

    We extend our previous studies of the neutrino fluxes expected from neutralino LSP annihilations inside the Sun to include variants of the minimal supersymmetric extension of the Standard Model (MSSM) with squark, slepton and gaugino masses constrained to be universal at the GUT scale, but allowing one or two non-universal supersymmetry-breaking parameters contributing to the Higgs masses (NUHM1,2). As in the constrained MSSM (CMSSM) with universal Higgs masses, there are large regions of the NUHM parameter space where the LSP density inside the Sun is not in equilibrium, so that the annihilation rate may be far below the capture rate, and there are also large regions where the capture rate is not dominated by spin-dependent LSP-proton scattering. The spectra possible in the NUHM are qualitatively similar to those in the CMSSM. We calculate neutrino-induced muon fluxes above a threshold energy of 10 GeV, appropriate for the IceCube/DeepCore detector, for points where the NUHM yields the correct cosmological r...

  5. Neutrino masses and neutrinoless double-beta decay

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, M. [Dipartimento di Fisica dell' Universita di Milano, Bicocca and sezioneINFN di Milano Bicocca (Italy)

    2008-12-15

    The potentials of Double Beta Decay experiments in the field of neutrino study are here discussed. Sensitivity and results are compared with the information coming from oscillation, cosmology and beta decay measurements. (Author)

  6. Constraints on the Active and Sterile Neutrino Masses from Beta-Ray Spectra: Past, Present and Future

    Czech Academy of Sciences Publication Activity Database

    Dragoun, Otokar; Vénos, Drahoslav

    2016-01-01

    Roč. 3, č. 1 (2016), s. 73-113 ISSN 1874-8430 R&D Projects: GA ČR(CZ) GAP203/12/1896 Institutional support: RVO:61389005 Keywords : active neutrino * Beta-ray spectrum * Beta- spectrometer * neutrino * neutrino mass * sterile neutrino Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders http://benthamopen.com/ABSTRACT/PHY-3-73

  7. Neutrinos and dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Schrempp, L.

    2008-02-15

    From the observed late-time acceleration of cosmic expansion arises the quest for the nature of Dark Energy. As has been widely discussed, the cosmic neutrino background naturally qualifies for a connection with the Dark Energy sector and as a result could play a key role for the origin of cosmic acceleration. In this thesis we explore various theoretical aspects and phenomenological consequences arising from non-standard neutrino interactions, which dynamically link the cosmic neutrino background and a slowly-evolving scalar field of the dark sector. In the considered scenario, known as Neutrino Dark Energy, the complex interplay between the neutrinos and the scalar field not only allows to explain cosmic acceleration, but intriguingly, as a distinct signature, also gives rise to dynamical, time-dependent neutrino masses. In a first analysis, we thoroughly investigate an astrophysical high energy neutrino process which is sensitive to neutrino masses. We work out, both semi-analytically and numerically, the generic clear-cut signatures arising from a possible time variation of neutrino masses which we compare to the corresponding results for constant neutrino masses. Finally, we demonstrate that even for the lowest possible neutrino mass scale, it is feasible for the radio telescope LOFAR to reveal a variation of neutrino masses and therefore to probe the nature of Dark Energy within the next decade. A second independent analysis deals with the recently challenged stability of Neutrino Dark Energy against the strong growth of hydrodynamic perturbations, driven by the new scalar force felt between neutrinos. Within the framework of linear cosmological perturbation theory, we derive the equation of motion of the neutrino perturbations in a model-independent way. This equation allows to deduce an analytical stability condition which translates into a comfortable upper bound on the scalar-neutrino coupling which is determined by the ratio of the densities in cold dark

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

    Indian Academy of Sciences (India)

    A4 is particularly well suited to describe three family mixing, and allows to explain the near tri-bimaximal mixing observed. .... A4 family symmetry [26,27] in which no right-handed neutrinos are introduced. Instead, the small neutrino .... The two different assignments of table 2 can lead to either. (mν) =.. a x 0 x 0 b. 0 b y.

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

    Energy Technology Data Exchange (ETDEWEB)

    Campagne, J.E.

    1995-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-15

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

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

    Directory of Open Access Journals (Sweden)

    Sandroos Joakim

    2016-01-01

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

  12. Exotic see-saw mechanism for neutrinos and leptogenesis in a Pati-Salam model

    Energy Technology Data Exchange (ETDEWEB)

    Addazi, Andrea [Dipartimento di Fisica, Università di L’Aquila,67010 Coppito, AQ (Italy); LNGS, Laboratori Nazionali del Gran Sasso,67010 Assergi AQ (Italy); Bianchi, Massimo [Dipartimento di Fisica, Università di Roma Tor Vergata,I.N.F.N. Sezione di Roma Tor Vergata,Via della Ricerca Scientifica, 1 00133 Roma (Italy); Ricciardi, Giulia [Dipartimento di Fisica “E. Pancini”, Università di Napoli “Federico II”,Complesso Universitario di Monte Sant’Angelo, Via Cintia, 80126 Napoli (Italy); I.N.F.N. Sezione di Napoli,Complesso Universitario di Monte Sant’Angelo, Via Cintia, 80126 Napoli (Italy)

    2016-02-04

    We discuss non-perturbative corrections to the neutrino sector, in the context of a D-brane Pati-Salam-like model, that can be obtained as a simple alternative to SO(10) GUT’s in theories with open and unoriented strings. In such D-brane models, exotic stringy instantons can correct the right-handed neutrino mass matrix in a calculable way, thus affecting mass hierarchies and modifying the see-saw mechanism to what we name exotic see-saw. For a wide range of parameters, a compact spectrum of right-handed neutrino masses can occur that gives rise to a predictive scenario for low energy observables. This model also provides a viable mechanism for Baryon Asymmetry in the Universe (BAU) through leptogenesis. Finally, a Majorana mass for the neutron is naturally predicted in the model, leading to potentially testable neutron-antineutron oscillations. Combined measurements in neutrino and neutron-antineutron sectors could provide precious informations on physics at the quantum gravity scale.

  13. Extended scaling and residual flavor symmetry in the neutrino Majorana mass matrix

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, Rome; Ghosal, Ambar [Saha Institute of Nuclear Physics, HBNI, Astroparticle Physics and Cosmology Division, Kolkata (India); Roy, Probir [Bose Institute, Center for Astroparticle Physics and Space Science, Kolkata (India)

    2016-12-15

    The residual symmetry approach, along with a complex extension for some flavor invariance, is a powerful tool to uncover the flavor structure of the 3 x 3 neutrino Majorana mass matrix M{sub ν} toward gaining insights into neutrino mixing. We utilize this to propose a complex extension of the real scaling ansatz for M{sub ν} which was introduced some years ago. Unlike the latter, our proposal allows a nonzero mass for each of the three light neutrinos as well as a nonvanishing θ{sub 13}. The generation of light neutrino masses via the type-I seesaw mechanism is also demonstrated. A major result of this scheme is that leptonic Dirac CP-violation must be maximal while atmospheric neutrino mixing does not need to be exactly maximal. Moreover, each of the two allowed Majorana phases, to be probed by the search for nuclear 0νββ decay, has to be at one of its two CP-conserving values. There are other interesting consequences such as the allowed occurrence of a normal mass ordering which is not favored by the real scaling ansatz. Our predictions will be tested in ongoing and future neutrino oscillation experiments at T2K, NOνA and DUNE. (orig.)

  14. Standard coupling unification in SO(10), hybrid seesaw neutrino mass and leptogenesis, dark matter, and proton lifetime predictions

    Energy Technology Data Exchange (ETDEWEB)

    Parida, M.K.; Nayak, Bidyut Prava; Satpathy, Rajesh [Centre of Excellence in Theoretical and Mathematical Sciences,Siksha ‘O’ Anusandhan University,Khandagiri Square, Bhubaneswar 751030 (India); Awasthi, Ram Lal [Indian Institute of Science Education and Research,Knowledge City, Sector 81, SAS Nagar, Manauli 140306 (India)

    2017-04-12

    We discuss gauge coupling unification of SU(3){sub C}×SU(2){sub L}×U(1){sub Y} descending directly from non-supersymmetric SO(10) while providing solutions to the three outstanding problems of the standard model: neutrino masses, dark matter, and the baryon asymmetry of the universe. Conservation of matter parity as gauged discrete symmetry for the stability and identification of dark matter in the model calls for high-scale spontaneous symmetry breaking through 126{sub H} Higgs representation. This naturally leads to the hybrid seesaw formula for neutrino masses mediated by heavy scalar triplet and right-handed neutrinos. Being quadratic in the Majorana coupling, the seesaw formula predicts two distinct patterns of right-handed neutrino masses, one hierarchical and another not so hierarchical (or compact), when fitted with the neutrino oscillation data. Predictions of the baryon asymmetry via leptogenesis are investigated through the decays of both the patterns of RHν masses. A complete flavor analysis has been carried out to compute CP-asymmetries including washouts and solutions to Boltzmann equations have been utilised to predict the baryon asymmetry. The additional contribution to vertex correction mediated by the heavy left-handed triplet scalar is noted to contribute as dominantly as other Feynman diagrams. We have found successful predictions of the baryon asymmetry for both the patterns of right-handed neutrino masses. The SU(2){sub L} triplet fermionic dark matter at the TeV scale carrying even matter parity is naturally embedded into the non-standard fermionic representation 45{sub F} of SO(10). In addition to the triplet scalar and the triplet fermion, the model needs a nonstandard color octet fermion of mass ∼5×10{sup 7} GeV to achieve precision gauge coupling unification at the GUT mass scale M{sub U}{sup 0}=10{sup 15.56} GeV. Threshold corrections due to superheavy components of 126{sub H} and other representations are estimated and found to be

  15. Cosmology favoring extra radiation and sub-eV mass sterile neutrinos as an option.

    Science.gov (United States)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G; Tamborra, Irene; Wong, Yvonne Y Y

    2010-10-29

    Precision cosmology and big-bang nucleosynthesis mildly favor extra radiation in the Universe beyond photons and ordinary neutrinos, lending support to the existence of low-mass sterile neutrinos. We use the WMAP 7-year data, small-scale cosmic microwave background observations from ACBAR, BICEP, and QuAD, the SDSS 7th data release, and measurement of the Hubble parameter from HST observations to derive credible regions for the assumed common mass scale m{s} and effective number N{s} of thermally excited sterile neutrino states. Our results are compatible with the existence of one or perhaps two sterile neutrinos, as suggested by LSND and MiniBooNE, if m{s} is in the sub-eV range.

  16. Neutrino flavor instabilities in a time-dependent supernova model

    Directory of Open Access Journals (Sweden)

    Sajad Abbar

    2015-12-01

    Full Text Available A dense neutrino medium such as that inside a core-collapse supernova can experience collective flavor conversion or oscillations because of the neutral-current weak interaction among the neutrinos. This phenomenon has been studied in a restricted, stationary supernova model which possesses the (spatial spherical symmetry about the center of the supernova and the (directional axial symmetry around the radial direction. Recently it has been shown that these spatial and directional symmetries can be broken spontaneously by collective neutrino oscillations. In this letter we analyze the neutrino flavor instabilities in a time-dependent supernova model. Our results show that collective neutrino oscillations start at approximately the same radius in both the stationary and time-dependent supernova models unless there exist very rapid variations in local physical conditions on timescales of a few microseconds or shorter. Our results also suggest that collective neutrino oscillations can vary rapidly with time in the regimes where they do occur which need to be studied in time-dependent supernova models.

  17. Observations in particle physics: from two neutrinos to standard model

    International Nuclear Information System (INIS)

    Lederman, L.M.

    1990-01-01

    Experiments, which have made their contribution to creation of the standard model, are discussed. Results of observations on the following concepts: long-lived neutral V-particles, violation of preservation of parity and charge invariance in meson decays, reaction with high-energy neutrino and existence of neutrino of two types, partons and dynamic quarks, dimuon resonance at 9.5 GeV in 400 GeV-proton-nucleus collisions, are considered

  18. Minimal supersymmetric SO(10) model and predictions for neutrino mixings and leptonic CP violation

    International Nuclear Information System (INIS)

    Goh, H.S.; Mohapatra, R.N.; Ng, Siew-Phang

    2003-01-01

    We discuss a minimal supersymmetric SO(10) model where B-L symmetry is broken by a 126 dimensional Higgs boson multiplet which also contributes to fermion masses in conjunction with a 10 dimensional superfield. This minimal Higgs boson choice provides a partial unification of neutrino flavor structure with that of quarks and has been shown to predict all three neutrino mixing angles and the solar mass splitting in agreement with observations, provided one uses the type II seesaw formula for neutrino masses. In this paper we generalize this analysis to include arbitrary CP phases in couplings and vacuum expectation values. We find that (i) the predictions for neutrino mixings are similar with U e3 ≅0.18 as before and other parameters in a somewhat bigger range and (ii) that to first order in the quark mixing parameter λ (the Cabibbo angle), the leptonic mixing matrix is CP conserving. We also find that in the absence of any higher dimensional contributions to fermion masses, the CKM phase is different from that of the standard model implying that there must be new contributions to quark CP violation from the supersymmetry breaking sector. Inclusion of higher dimensional terms however allows the standard model CKM phase to be maintained

  19. SU(2)L×U(1)Y×S3×D model for atmospheric and solar neutrino deficits

    Science.gov (United States)

    Ray, Asim K.; Sarkar, Saswati

    2000-02-01

    Motivated by the recent Super-Kamiokande experiment on atmospheric and solar neutrinos we propose a see-saw model of three generations of neutrinos based on the gauge group SU(2)L×U(1)Y with the discrete symmetries (S3×D) and three right handed singlet neutrinos so that this model can accommodate the recent Super-Kamiokande data on atmospheric and solar neutrino oscillations. The model predicts maximal mixing between νμ and ντ with sin2 2θμτ=1 as required by the atmospheric neutrino data and small mixing between νe and νμ with sin22θeμ~(10-2-10-3) as a possible explanation of the solar neutrino deficit through the MSW mechanism. The model admits two mass scales of which one breaks the electroweak symmetry and the other is responsible for the breaking of the lepton number symmetry at GUT scale leading to a small Majorana mass of the left handed doublet neutrinos.

  20. Precision electron-capture energy in {sup 202}Pb and its relevance for neutrino mass determination

    Energy Technology Data Exchange (ETDEWEB)

    Welker, A. [CERN, Geneva (Switzerland); Technische Universitaet Dresden, Dresden (Germany); Filianin, P. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Althubiti, N.A.S. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Atanasov, D.; Blaum, K.; Eliseev, S.; Kreim, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Cocolios, T.E. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Herfurth, F.; Neidherr, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Manea, V. [CERN, Geneva (Switzerland); Novikov, Yu. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Physics Faculty, St. Petersburg State University (Russian Federation); Rosenbusch, M.; Schweikhard, L.; Wienholtz, F. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Greifswald (Germany); Wolf, R.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); The University of Sydney, ARC Centre of Excellence for Engineered Quantum Systems, Sydney (Australia); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany)

    2017-07-15

    Within the framework of an extensive programme devoted to the search for alternative candidates for the neutrino mass determination, the atomic mass difference between {sup 202}Pb and {sup 202}Tl has been measured with the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The obtained value Q{sub EC} = 38.8(43) keV is three times more precise than the AME2012 value. While it will probably not lead to a replacement of {sup 163}Ho in modern experiments on the determination of the electron-neutrino mass, the electron capture in {sup 202}Pb would however allow a determination of the electron-neutrino mass on the few-eV level using a cryogenic micro-calorimeter. (orig.)

  1. Matter power spectra in viable f(R gravity models with massive neutrinos

    Directory of Open Access Journals (Sweden)

    Chao-Qiang Geng

    2015-01-01

    Full Text Available We investigate the matter power spectra in the power law and exponential types of viable f(R theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, ∑mν, is allowed in the viable f(R models than that in the ΛCDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get ∑mν<0.451(0.214 eV at 95% C.L. in the Starobinsky (exponential model, while the corresponding one for the ΛCDM model is ∑mν<0.200 eV. Furthermore, by treating the effective number of neutrino species Neff as a free parameter along with ∑mν, we find that Neff=3.78−0.84+0.64(3.47−0.60+0.74 and ∑mν=0.533−0.411+0.254 (<0.386 eV at 95% C.L. in the Starobinsky (exponential model.

  2. Matter power spectra in viable f(R) gravity models with massive neutrinos

    International Nuclear Information System (INIS)

    Geng, Chao-Qiang; Lee, Chung-Chi; Shen, Jia-Liang

    2015-01-01

    We investigate the matter power spectra in the power law and exponential types of viable f(R) theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, ∑m ν , is allowed in the viable f(R) models than that in the ΛCDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get ∑m ν <0.451(0.214) eV at 95% C.L. in the Starobinsky (exponential) model, while the corresponding one for the ΛCDM model is ∑m ν <0.200 eV. Furthermore, by treating the effective number of neutrino species N eff as a free parameter along with ∑m ν , we find that N eff =3.78 −0.84 +0.64 (3.47 −0.60 +0.74 ) and ∑m ν =0.533 −0.411 +0.254 (<0.386) eV at 95% C.L. in the Starobinsky (exponential) model

  3. An upper limit on the $\\tau$ neutrino mass from three- and five-prong tau decays

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Becker, U; Bright-Thomas, P G; Casper, David William; Cattaneo, M; Cerutti, F; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Lehraus, Ivan; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Boccali, T; Focardi, E; Parrini, G; Zachariadou, K; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Stacey, A M; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Sloan, Terence; Williams, M I; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Diaconu, C A; Etienne, F; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Mannert, C; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Schune, M H; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Konstantinidis, N P; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G

    1998-01-01

    A bound on the tau neutrino mass is established using the data collected from 1991 to 1995 at Ecm = M(Z) with the ALEPH detector. Two separate limits are derived by fitting the distribution of visible energy vs invariant mass in tau+ -> pi+ pi+ pi- nu and tau+ -> pi+ pi+ pi- pi- pi+ (pi0) nu decays. The two results are combined to obtain a 95 % confidence level upper limit of 18.2 MeV/c^2 on the mass of the tau neutrino.

  4. Neutrino 2004: Collection of Presentations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The scientific program covers the latest developments in neutrino physics, astrophysics and related topics through a set of invited talks and 2 poster sessions. The following issues are addressed: - solar neutrinos, - atmospheric neutrinos, - short and long baseline experiments, - neutrino oscillations, - double beta decay, - direct neutrino mass limits, - theory for neutrino masses, neutrino telescopes and ultra-high energy neutrinos, - dark matter searches, - neutrino in astrophysics and cosmology, and - future projects beams and experiments.

  5. Neutrino 2004: Collection of Presentations

    International Nuclear Information System (INIS)

    2004-01-01

    The scientific program covers the latest developments in neutrino physics, astrophysics and related topics through a set of invited talks and 2 poster sessions. The following issues are addressed: - solar neutrinos, - atmospheric neutrinos, - short and long baseline experiments, - neutrino oscillations, - double beta decay, - direct neutrino mass limits, - theory for neutrino masses, neutrino telescopes and ultra-high energy neutrinos, - dark matter searches, - neutrino in astrophysics and cosmology, and - future projects beams and experiments

  6. Theoretical aspects of neutrino mass and lepton flavour violation

    Indian Academy of Sciences (India)

    We consider lepton flavour violation (LFV) in the charged lepton sector both from the bottom-up effective Lagrangian approach and from the top-down approach via various case studies that have been analysed. The implications for LFV studies at the LHC is briefly discussed. Finally the nature of LFV in the neutrino sector is ...

  7. Anomalous leptonic U(1) symmetry: Syndetic origin of the QCD axion, weak-scale dark matter, and radiative neutrino mass

    Science.gov (United States)

    Ma, Ernest; Restrepo, Diego; Zapata, Óscar

    2018-01-01

    The well-known leptonic U(1) symmetry of the Standard Model (SM) of quarks and leptons is extended to include a number of new fermions and scalars. The resulting theory has an invisible QCD axion (thereby solving the strong CP problem), a candidate for weak-scale dark matter (DM), as well as radiative neutrino masses. A possible key connection is a color-triplet scalar, which may be produced and detected at the Large Hadron Collider.

  8. Implications of right-handed neutrinos in B -L extended standard model with scalar dark matter

    Science.gov (United States)

    Bandyopadhyay, Priyotosh; Chun, Eung Jin; Mandal, Rusa

    2018-01-01

    We investigate the standard model (SM) with a U (1 )B-L gauge extension where a B -L charged scalar is a viable dark matter (DM) candidate. The dominant annihilation process, for the DM particle is through the B -L symmetry breaking scalar to a right-handed neutrino pair. We exploit the effect of decay and inverse decay of the right-handed neutrino in thermal relic abundance of the DM. Depending on the values of the decay rate, the DM relic density can be significantly different from what is obtained in the standard calculation assuming the right-handed neutrino is in thermal equilibrium and there appear different regions of the parameter space satisfying the observed DM relic density. For a DM mass less than O (TeV ) , the direct detection experiments impose a competitive bound on the mass of the U (1 )B-L gauge boson Z' with the collider experiments. Utilizing the nonobservation of the displaced vertices arising from the right-handed neutrino decays, the bound on the mass of Z' has been obtained at present and higher luminosities at the LHC with 14 TeV center of mass energy where an integrated luminosity of 100 fb-1 is sufficient to probe mZ'˜5.5 TeV .

  9. A search for decays of heavy neutrinos in the mass range 0.5-2.8 GeV

    International Nuclear Information System (INIS)

    Dorenbosch, J.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Berger, C.; Bergsma, F.; Capone, A.; Flegel, W.; Lanceri, L.; Metcalf, M.; Nieuwenhuis, C.; Panman, J.; Winter, K.; Abt, I.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Hebbeker, T.; Niebergall, F.; Schuett, P.; Staehelin, P.; Baroncelli, A.; Bosio, C.; Santoni, C.; Tortora, L.; Valente, V.

    1986-01-01

    A search for decays of heavy neutrinos was conducted by the CHARM Collaboration in a prompt neutrino beam produced by dumping 400 GeV protons in a Cu target, and in the CERN wide-band neutrino beam produced by 400 GeV primary protons. No candidate event was found. In the beam-dump experiment heavy neutrinos have been assumed to be produced by mixing in charmed D meson decays. Neutrinos decaying into e + e - νsub(e), e + e - μ + e - νsub(e),e - +μ - νsub(μ), and μ + μ - νsub(μ) were searched for. Limits of vertical strokeUsub(ei)vertical stroke 2 , vertical strokeUsub(μ1)vertical stroke=2 -7 were obtained for neutrino masses around 1.5 GeV. In the wide-band experiment heavy neutrinos were assumed to be produced by neutral-current neutrino interactions in the CHARM calorimeter. Here a search was made for neutrinos decaying into a μ and hadrons. This experiment is sensitive to decays of neutrinos with mass in the range 0.5-2.8 GeV with limits of vertical strokeUsub(μi)vertical stroke 2 -4 for masses around 2.5 GeV. These measurements extend our previous results in the mass range 10-400 MeV. (orig.)

  10. Anatomy of Higgs mass in supersymmetric inverse seesaw models

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Eung Jin, E-mail: ejchun@kias.re.kr [Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Mummidi, V. Suryanarayana, E-mail: soori9@cts.iisc.ernet.in [Centre for High Energy Physics, Indian Institute of Science, Bangalore 560012 (India); Vempati, Sudhir K., E-mail: vempati@cts.iisc.ernet.in [Centre for High Energy Physics, Indian Institute of Science, Bangalore 560012 (India)

    2014-09-07

    We compute the one loop corrections to the CP-even Higgs mass matrix in the supersymmetric inverse seesaw model to single out the different cases where the radiative corrections from the neutrino sector could become important. It is found that there could be a significant enhancement in the Higgs mass even for Dirac neutrino masses of O(30) GeV if the left-handed sneutrino soft mass is comparable or larger than the right-handed neutrino mass. In the case where right-handed neutrino masses are significantly larger than the supersymmetry breaking scale, the corrections can utmost account to an upward shift of 3 GeV. For very heavy multi TeV sneutrinos, the corrections replicate the stop corrections at 1-loop. We further show that general gauge mediation with inverse seesaw model naturally accommodates a 125 GeV Higgs with TeV scale stops.

  11. An assessment of anti-neutrino mass determination via electrostatic measurements of tritium beta-decay

    International Nuclear Information System (INIS)

    Le Bas, P.A.

    1984-01-01

    Data on the mass of the anti-neutrino determined via electrostatic measurements of tritium beta-decay are assessed. Relativistic calculations concerning the finite mass of the electron anti-neutrino and the recoil of the nucleus, are given for the theoretical end-point spectrum of tritium beta-decay. The specifications are given for an electrostatic Spherical Retarding Beta-Spectrometer, and an electrostatic Cylindrical Mirror Analyser, both used in the tritium beta-decay experiment. The electrostatic measurements lead to a value of less than 50 ev (90% C.L.) for the electron anti-neutrino mass. These results are discussed in terms of the resolution of the electrostatic equipment and the Monte Carlo simulations of the data collection. (UK)

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  13. Sterile Neutrino Search with MINOS

    Energy Technology Data Exchange (ETDEWEB)

    Devan, Alena V. [College of William and Mary, Williamsburg, VA (United States)

    2015-08-01

    MINOS, Main Injector Neutrino Oscillation Search, is a long-baseline neutrino oscillation experiment in the NuMI muon neutrino beam at the Fermi National Accelerator Laboratory in Batavia, IL. It consists of two detectors, a near detector positioned 1 km from the source of the beam and a far detector 734 km away in Minnesota. MINOS is primarily designed to observe muon neutrino disappearance resulting from three flavor oscillations. The Standard Model of Particle Physics predicts that neutrinos oscillate between three active flavors as they propagate through space. This means that a muon-type neutrino has a certain probability to later interact as a different type of neutrino. In the standard picture, the neutrino oscillation probabilities depend only on three neutrino flavors and two mass splittings, Δm2. An anomaly was observed by the LSND and MiniBooNE experiments that suggests the existence of a fourth, sterile neutrino flavor that does not interact through any of the known Standard Model interactions. Oscillations into a theoretical sterile flavor may be observed by a deficit in neutral current interactions in the MINOS detectors. A distortion in the charged current energy spectrum might also be visible if oscillations into the sterile flavor are driven by a large mass-squared difference, ms2 ~ 1 eV2. The results of the 2013 sterile neutrino search are presented here.

  14. Neutrino physics with JUNO

    Science.gov (United States)

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

    2016-03-01

    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 (MH) as a primary physics goal. The excellent energy resolution and the large fiducial volume anticipated for the JUNO detector offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. In this document, we present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. Following an introduction summarizing the current status and open issues in neutrino physics, we discuss how the detection of antineutrinos generated by a cluster of nuclear power plants allows the determination of the neutrino MH at a 3-4σ significance with six years of running of JUNO. The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters {{sin}}2{θ }12, {{Δ }}{m}212, and | {{Δ }}{m}{ee}2| to an accuracy of better than 1%, which will play a crucial role in the future unitarity test of the MNSP matrix. The JUNO detector is capable of observing not only antineutrinos from the power plants, but also neutrinos/antineutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, and solar neutrinos. As a result of JUNO's large size, excellent energy resolution, and vertex reconstruction capability, interesting new data on these topics can be collected. For example, a neutrino burst from a typical core-collapse supernova at a distance of 10 kpc would lead to ˜5000 inverse-beta-decay events and ˜2000 all-flavor neutrino-proton ES events in JUNO, which are of crucial importance for understanding the mechanism of supernova explosion and for exploring novel phenomena such as collective neutrino oscillations

  15. The mass of the electron neutrino and electron capture in 163Ho

    International Nuclear Information System (INIS)

    Yasumi, S.; Rajasekaran, G.; Ando, M.; Ochiai, F.; Ikeda, H.; Ohta, T.; Stefan, P.M.; Maruyama, M.; Nashimoto, N.; Fujioka, M.; Ishii, K.; Shinozuka, T.; Sera, K.; Omori, T.; Izawa, G.; Yagi, M.; Masumoto, K.; Shima, K.

    1983-01-01

    To determine the mass of the electron neutrino, electron capture in 163 Ho was studied. From the intensity of M X-rays and the total number of 163 Ho atoms in a source, as determined by the PIXE method, the partial M-capture half life of 163 Ho was estimated to be (4.5 +- 1.5) x 10 4 yr. A relation between the Q-value of 163 Ho and the mass of the electron neutrino was obtained. (orig.)

  16. Magic neutrino mass matrix and the Bjorken-Harrison-Scott parameterization

    International Nuclear Information System (INIS)

    Lam, C.S.

    2006-01-01

    Observed neutrino mixing can be described by a tribimaximal MNS matrix. The resulting neutrino mass matrix in the basis of a diagonal charged lepton mass matrix is both 2-3 symmetric and magic. By a magic matrix, I mean one whose row sums and column sums are all identical. I study what happens if 2-3 symmetry is broken but the magic symmetry is kept intact. In that case, the mixing matrix is parameterized by a single complex parameter U e3 , in a form discussed recently by Bjorken, Harrison, and Scott

  17. Technical Note: Neutrino Speed and Mass Theory and its Deep Impacts on Cosmology

    Science.gov (United States)

    Frystacki, H.

    In the second half of September 2011 a neutrino beam from a CERN lab in Geneva, Switzerland shot 732 km to the National Institute of Nuclear Physics Gran Sasso lab in Italy seemed to travel 0.0025% faster through Earth than speed of light in a vacuum. Not looking at the accuracy of this disputed experiment it shows that neutrinos are very peculiar subatomic particles because they travel either with a speed very close to the speed of light, or at speed of light, or even above if the experiment turns out to be repeatable. This raises the question about the nature of neutrinos and if we can detect a feasible process that causes the extremely small mass of neutrinos that is obviously not subject to any relativistic mass increase. A new approach to the well-known simultaneity of relativity of events with Planck's quantization scale of length and time may solve the riddle for the strange nature of neutrinos and the unexpected mass feature they have. This discussion opens the horizon to hidden forms of energies throughout vacuum of space by introducing quantized rotary space-time elements and examining the relativity of simultaneity in a way it has never done before.

  18. The nucleon axial mass and the MiniBooNE CCQE neutrino-nucleus data

    International Nuclear Information System (INIS)

    Nieves, J; Ruiz Simo, I; Vacas, M J Vicente

    2013-01-01

    We analyze the MiniBooNE CCQE dσ/dT μ d cos θ μ data using a theoretical model that has proved to be quite successful in the analysis of nuclear reactions with electron, photon and pion probes. We find that RPA and multinucleon knockout turn out to be essential for the description of the MiniBooNE data. We show these measurements are fully compatible with former determinations of nucleon axial mass M A , in contrast with several previous analyses, which have suggested an anomalously large value. We find, M A = 1.08 ± 0.03 GeV. We also argue that the procedure, commonly used to reconstruct the neutrino energy for QE events from the muon angle and energy, could be unreliable for a wide region of the phase space, due to the large importance of multinucleon events.

  19. arXiv Neutrino masses and cosmology with Lyman-alpha forest power spectrum

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Baur, Julien; Magneville, Christophe; Rossi, Graziano; Lesgourgues, Julien; Borde, Arnaud; Burtin, Etienne; LeGoff, Jean-Marc; Rich, James; Viel, Matteo; Weinberg, David

    2015-01-01

    We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the $\\Lambda$CDM model, using the one-dimensional Ly$\\alpha$-forest power spectrum measured by Palanque-Delabrouille et al. (2013) from SDSS-III/BOSS, complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by Palanque-Delabrouille et al. (2015) by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Ly$\\alpha$ data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ...

  20. Probing the neutrino mass ordering with KM3NeT-ORCA: analysis and perspectives

    Science.gov (United States)

    Capozzi, Francesco; Lisi, Eligio; Marrone, Antonio

    2018-02-01

    The discrimination of the two possible options for the neutrino mass ordering (normal or inverted) is a major goal for current and future neutrino oscillation experiments. Such a goal might be reached by observing high-statistics energy-angle spectra of events induced by atmospheric neutrinos and antineutrinos propagating in the Earth matter. Large volume water-Cherenkov detectors envisaged to this purpose include the so-called KM3NeT-ORCA project (in seawater) and the IceCube-PINGU project (in ice). Building upon a previous work focused on PINGU, we study in detail the effects of various systematic uncertainties on the ORCA sensitivity to the mass ordering, for the reference configuration with 9 m vertical spacing. We point out the need to control spectral shape uncertainties at the percent level, the effects of better priors on the {θ }23 mixing parameter, and the benefits of an improved flavor identification in reconstructed ORCA events.

  1. KeV right-handed neutrinos from type II seesaw mechanism in a 3-3-1 model

    International Nuclear Information System (INIS)

    Cogollo, D.; Diniz, H.; Pires, Carlos

    2009-01-01

    Full text. Right-handed neutrinos were not detected yet in nature. Nobody knows if they are light or heavy particles. Light right-handed neutrinos are phenomenologically interesting because of their intricate implications in particle physics, astrophysics and cosmology. For example, warm dark matter in the form of sterile neutrinos with mass in the KeV range has been advocated as a solution to the conflict among cold dark matter and observations of clustering on sub galactic scales. There are many papers devoted to the study of such implications. However, as far as we know, there are few ones devoted to the development of mechanisms that could lead to light right-handed neutrinos. Suppose a scenario where the left-handed neutrinos as well as the right-handed ones are all light particles. In a scenario like this, a challenging task to particle physics would be to develop a seesaw mechanism in the framework of some extension of the standard model that could induce the small masses of these neutrinos. In this regard, an even more interesting scenario would be one where the explanation of the lightness of both left-handed and right-handed neutrino masses would have a common origin. In this paper we consider a variant of the gauge models based in the SU(3) C xSU(3) L xU(1) N (3-3-1) symmetry called 3-3-1 model with right-handed neutrinos and adapt the type II seesaw mechanism in this framework. (author)

  2. Prompt atmospheric neutrino flux from the various QCD models

    Directory of Open Access Journals (Sweden)

    Jeong Yu Seon

    2017-01-01

    Full Text Available We evaluate the prompt atmospheric neutrino flux using the different QCD models for heavy quark production including the b quark contribution. We include the nuclear correction and find it reduces the fluxes by 10% – 50% according to the models. Our heavy quark results are compared with experimental data from RHIC, LHC and LHCb.

  3. Oscillation properties of active and sterile neutrinos and neutrino anomalies at short distances

    Energy Technology Data Exchange (ETDEWEB)

    Khruschov, V. V., E-mail: khruschov-vv@nrcki.ru; Fomichev, S. V., E-mail: fomichev-sv@nrcki.ru; Titov, O. A., E-mail: titov-oa@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-09-15

    A generalized phenomenological (3 + 2 + 1) model featuring three active and three sterile neutrinos that is intended for calculating oscillation properties of neutrinos for the case of a normal active neutrino mass hierarchy and a large splitting between the mass of one sterile neutrino and the masses of the other two sterile neutrinos is considered. A new parametrization and a specific form of the general mixing matrix are proposed for active and sterile neutrinos with allowance for possible CP violation in the lepton sector, and test values are chosen for the neutrino masses and mixing parameters. The probabilities for the transitions between different neutrino flavors are calculated, and graphs representing the probabilities for the disappearance of muon neutrinos/antineutrinos and the appearance of electron neutrinos/antineutrinos in a beam of muon neutrinos/antineutrinos versus the distance from the neutrino source for various values of admissible model parameters at neutrino energies not higher than 50 MeV, as well as versus the ratio of this distance to the neutrino energy, are plotted. It is shown that the short-distance accelerator anomaly in neutrino data (LNSD anomaly) can be explained in the case of a specific mixing matrix for active and sterile neutrinos (which belongs to the a{sub 2} type) at the chosen parameter values. The same applies to the short-distance reactor and gallium anomalies. The theoretical results obtained in the present study can be used to interpret and predict the results of ground-based neutrino experiments aimed at searches for sterile neutrinos, as well as to analyze some astrophysical observational data.

  4. Experimental data on solar neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Ludhova, Livia [INFN, Milano (Italy)

    2016-04-15

    Neutrino physics continues to be a very active research field, full of opened fundamental questions reaching even beyond the Standard Model of elementary particles and towards a possible new physics. Solar neutrinos have played a fundamental historical role in the discovery of the phenomenon of neutrino oscillations and thus non-zero neutrino mass. Even today, the study of solar neutrinos provides an important insight both into the neutrino as well as into the stellar and solar physics. In this section we give an overview of the most important solar-neutrino measurements from the historical ones up to the most recent ones. We cover the results from the experiments using radio-chemic (Homestake, SAGE, GNO, GALLEX), water Cherenkov (Kamiokande, Super-Kamiokande, SNO), and the liquid-scintillator (Borexino, KamLAND) detection techniques. (orig.)

  5. Flipped Heavy Neutrinos from the Solar Neutrino Problem to Baryogenesis

    CERN Document Server

    Ellis, Jonathan Richard; Olive, Keith A

    1993-01-01

    We discuss baryogenesis using the flipped $SU(5)$ model for lepton mass matrices. We show that the generalized see-saw mechanism in this model can not only provide MSW neutrino mixing suitable for solving the solar neutrino problem, and supply a hot dark matter candidate ($\

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-15

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

  7. Identifying neutrino mass hierarchy at extremely small theta13 through earth matter effects in a supernova signal.

    Science.gov (United States)

    Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro

    2008-10-24

    Collective neutrino flavor transformations deep inside a supernova are sensitive to the neutrino mass hierarchy even at extremely small values of theta_(13). Exploiting this effect, we show that comparison of the antineutrino signals from a galactic supernova in two megaton class water Cherenkov detectors, one of which is shadowed by Earth, will enable us to distinguish between the hierarchies if sin(2)theta_(13) < or approximately 10(-5), where long baseline neutrino experiments would be ineffectual.

  8. Neutrino cosmology

    International Nuclear Information System (INIS)

    Bludman, S.A.

    1976-01-01

    Cosmological data are reviewed, questioning whether the universe may be open and dominated by neutrinos and gravitons rather than by baryons. The thermal history of the Lepton Era is investigated incorporating the effects of neutral currents, additional neutrinos, and a small neutrino mass. In the canonical version of Big Bang cosmology (equal numbers of neutrinos and antineutrinos), and neutrino number and energy density is, like that of photons, gravitationally insignificant unless the neutrino has a small mass (approximately 10 eV). The neutrino sea can be cosmologically significant if it is degenerate (so that the net leptonic or muonic charge is nonzero) with approximately 7 x 10 5 neutrinos (or antineutrinos) per cm 3 . This density homogeneously spread out is still so low that even the most energetic cosmic ray protons will not be stopped, even if neutral currents exist with the usual weak strength. It these degenerate neutrinos have a small mass (approximately 0.5 eV), they will condense into degenerate neutrino superstars of the size and mass of galactic clusters. If neutral currents make the (eν) (eν) coupling five times greater than what it is in V - A theory, nucleosynthesis commences a little earlier than conventionally assumed. This increases the cosmological He 4 abundance predicted only slightly from Y = 0.27 to Y = 0.29. An appendix reviews the effect of neutral currents on neutrino processes in stars. (author)

  9. Search for new candidates for the neutrino-oriented mass determination by electron-capture

    CERN Multimedia

    Herfurth, F; Boehm, C; Blaum, K; Beck, D

    2008-01-01

    This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

  10. Forecasting neutrino masses from combining KATRIN and the CMB observations: Frequentist and Bayesian analyses

    Science.gov (United States)

    Host, Ole; Lahav, Ofer; Abdalla, Filipe B.; Eitel, Klaus

    2007-12-01

    We present a showcase for deriving bounds on the neutrino masses from laboratory experiments and cosmological observations. We compare the frequentist and Bayesian bounds on the effective electron neutrino mass mβ which the KATRIN neutrino mass experiment is expected to obtain, using both an analytical likelihood function and Monte Carlo simulations of KATRIN. Assuming a uniform prior in mβ, we find that a null result yields an upper bound of about 0.17 eV at 90% confidence in the Bayesian analysis, to be compared with the frequentist KATRIN reference value of 0.20 eV. This is a significant difference when judged relative to the systematic and statistical uncertainties of the experiment. On the other hand, an input mβ=0.35eV, which is the KATRIN 5σ detection threshold, would be detected at virtually the same level. Finally, we combine the simulated KATRIN results with cosmological data in the form of present (post-WMAP) and future (simulated Planck) observations. If an input of mβ=0.2eV is assumed in our simulations, KATRIN alone excludes a zero neutrino mass at 2.2σ. Adding Planck data increases the probability of detection to a median 2.7σ. The analysis highlights the importance of combining cosmological and laboratory data on an equal footing.

  11. Forecasting neutrino masses from combining KATRIN and the CMB observations: Frequentist and Bayesian analyses

    International Nuclear Information System (INIS)

    Host, Ole; Lahav, Ofer; Abdalla, Filipe B.; Eitel, Klaus

    2007-01-01

    We present a showcase for deriving bounds on the neutrino masses from laboratory experiments and cosmological observations. We compare the frequentist and Bayesian bounds on the effective electron neutrino mass m β which the KATRIN neutrino mass experiment is expected to obtain, using both an analytical likelihood function and Monte Carlo simulations of KATRIN. Assuming a uniform prior in m β , we find that a null result yields an upper bound of about 0.17 eV at 90% confidence in the Bayesian analysis, to be compared with the frequentist KATRIN reference value of 0.20 eV. This is a significant difference when judged relative to the systematic and statistical uncertainties of the experiment. On the other hand, an input m β =0.35 eV, which is the KATRIN 5σ detection threshold, would be detected at virtually the same level. Finally, we combine the simulated KATRIN results with cosmological data in the form of present (post-WMAP) and future (simulated Planck) observations. If an input of m β =0.2 eV is assumed in our simulations, KATRIN alone excludes a zero neutrino mass at 2.2σ. Adding Planck data increases the probability of detection to a median 2.7σ. The analysis highlights the importance of combining cosmological and laboratory data on an equal footing

  12. The neutrino mass and other possible signals of lepton-number violation in supersymmetric theories

    OpenAIRE

    Polonsky, Nir

    1996-01-01

    We review a recently proposed framework in which the neutrino mass is a signal of supersymmetry breaking and is suppressed dynamically. In addition, we briefly comment on some possible consequences of general lepton-number violation in supersymmetric theories, e.g., dijet and multijet signals and $jj \\rightarrow ll\\gamma\\gamma$.

  13. The revival of two old ways to measure the electron-neutrino mass

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Meanwhile, the Tritium-decay neutrino-mass limits have improved by a factor of 15, and the difficulty of the experiments by the cube of that figure. Can the "calorimetric" EC theory cope with this increased challenge? I shall answer this question affirmatively. I shall also broach the ongoing beta-decay and EC experiments and report on progress i...

  14. KATRIN :a New Beta-Spectroscopic Experiment to Determine the Neutrino Mass

    Czech Academy of Sciences Publication Activity Database

    Dragoun, Otokar

    2007-01-01

    Roč. 958, - (2007), s. 193-196. ISBN 978-0-7354-0472-4. ISSN N R&D Projects: GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutrino mass * beta ray spectroscopy Subject RIV: BE - Theoretical Physics

  15. Final results phase II of the Mainz neutrino mass search in tritium ß decay

    Czech Academy of Sciences Publication Activity Database

    Kraus, Ch.; Bornschein, B.; Bornschein, L.; Bonn, J.; Flatt, B.; Kovalík, Alojz; Ostrick, B.; Otten, E.W.; Schall, J.P.; Thümmler, Th.; Weinheimer, Ch.

    2005-01-01

    Roč. 40, - (2005), s. 447-468 ISSN 1434-6001 R&D Projects: GA MŠk 1P04LA213 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutrino mass * tritium beta decay Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.659, year: 2005

  16. Seesaw induced electroweak scale, the hierarchy problem and sub-eV neutrino masses

    International Nuclear Information System (INIS)

    Atwood, D.; Bar-Shalom, S.; Soni, A.

    2006-01-01

    We describe a model for the scalar sector where all interactions occur either at an ultra-high scale, Λ U ∝10 16 -10 19 GeV, or at an intermediate scale, Λ I =10 9 -10 11 GeV. The interaction of physics on these two scales results in an SU(2) Higgs condensate at the electroweak (EW) scale, Λ EW , through a seesaw-like Higgs mechanism, Λ EW ∝Λ I 2 /Λ U , while the breaking of the SM SU(2) x U(1) gauge symmetry occurs at the intermediate scale Λ I . The EW scale is, therefore, not fundamental but is naturally generated in terms of ultra-high energy phenomena and so the hierarchy problem is alleviated. We show that the class of such ''seesaw Higgs'' models predict the existence of sub-eV neutrino masses which are generated through a ''two-step'' seesaw mechanism in terms of the same two ultra-high scales: m ν ∝Λ I 4 /Λ U 3 ∝Λ EW 2 /Λ U . The neutrinos can be either Dirac or Majorana, depending on the structure of the scalar potential. We also show that our seesaw Higgs model can be naturally embedded in theories with tiny extra dimensions of size R∝Λ U -1 ∝10 -16 fm, where the seesaw induced EW scale arises from a violation of a symmetry at a distant brane; in particular, in the scenario presented there are seven tiny extra dimensions. (orig.)

  17. The Neutrino mass matrix after Kamland and SNO salt enhanced results

    CERN Document Server

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

    2003-01-01

    An updated analysis of all available neutrino oscillation evidence in Solar experiments including the latest SNO ES,CC and NC data (254d live time, NaCL enhanced efficiency) is presented. We obtain, for the fraction of active oscillating neutrinos: sin^2alpha=(\\Phi_{NC}-\\Phi_{CC})/(\\Phi_{SSM}-\\Phi_{CC})=0.94^{+0.0.065}_{-0.060 } nearly 20\\sigma from the pure sterile oscillation case. The fraction of oscillating sterile neutrinos cos^2\\alpha \\lsim 0.12 (1 sigma CL). At face value, these results might slightly favour the existence of a small sterile oscillating sector. In the framework of two active neutrino oscillations we determine individual neutrino mixing parameters and their errors we obtain Delta m^2= 7.01\\pm 0.08 \\times 10^{-5} eV^2, tan^2 theta=0.42^{+0.12}_{-0.07}. The main difference with previous analysis is a better resolution in parameter space. In particular the secondary region at larger mass differences (LMAII) is now excluded at 95% CL. The combined analysis of solar and Kamland data concludes...

  18. Accelerator neutrinos

    International Nuclear Information System (INIS)

    Autiero, D.; Declais, Y.

    2005-01-01

    In the last years neutrino physics was shaken by many important experimental results bringing solid proofs in favor of neutrino oscillations. The goal of the present and future generation of experiments at accelerators is to complete the comprehension of neutrino mixing and of the pattern of neutrino masses, perform precise measurements of all these parameters and investigate CP violation in the neutrino sector. Most of these goals will be achieved with the study of ν μ → ν e oscillations, which are mainly ruled by the still unknown mixing angle Θ 13 . A multi-step experimental strategy has to be attempted, depending on the magnitude of Θ 13 . (authors)

  19. Experimental bounds on sterile neutrino mixing angles

    CERN Document Server

    Ruchayskiy, Oleg

    2012-01-01

    We derive bounds on the mixing between the left-chiral ("active") and the right-chiral ("sterile") neutrinos, provided from the combination of neutrino oscillation data and direct experimental searches for sterile neutrinos. We demonstrate that the mixing of sterile neutrinos with any flavour can be significantly suppressed, provided that the angle theta_13 is non-zero. This means that the lower bounds on sterile neutrino lifetime, coming from the negative results of direct experimental searches can be relaxed (by as much as the order of magnitude at some masses). We also demonstrate that the results of the negative searches of sterile neutrinos with PS191 and CHARM experiments are not applicable directly to the see-saw models. The reinterpretation of these results provides up to the order of magnitude stronger bounds on sterile neutrino lifetime than previously discussed in the literature. We discuss the implications of our results for the Neutrino Minimal Standard Model (the NuMSM).

  20. Calorimetric measurements of $^{163}$ holmium decay as tools to determine the electron neutrino mass

    CERN Document Server

    De Rújula, Alvaro

    1982-01-01

    Computes the spectrum of 'calorimetric' energy in the electron capture decay of /sup 163/Ho. A calorimetric experiment would yield an excellent determination of (/sup 163/Ho, /sup 163/Dy) mass difference. The proximity of the spectral endpoint to an atomic resonance makes the fraction of events that are sensitive to a non-zero neutrino mass superior in /sup 163/Ho decay than in tritium decay.

  1. Gravitationally confined relativistic neutrinos

    Science.gov (United States)

    Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.

    2017-09-01

    Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.

  2. A model of neutrino and Higgs physics at the electroweak scale

    International Nuclear Information System (INIS)

    Aranda, Alfredo; Blanno, Omar; Diaz-Cruz, J. Lorenzo

    2008-01-01

    We present and explore the Higgs physics of a model that in addition to the Standard Model fields includes a lepton number violating singlet scalar field. Based on the fact that the only experimental data we have so far for physics beyond the Standard Model is that of neutrino physics, we impose a constraint for any addition not to introduce new higher scales. As such, we introduce right-handed neutrinos with an electroweak scale mass. We study the Higgs decay H→νν and show that it leads to different signatures compared to those in the Standard Model, making it possible to detect them and to probe the nature of their couplings

  3. A model of neutrino and Higgs physics at the electroweak scale

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, Alfredo [Dual CP Institute of High Energy Physics (Mexico); Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima (Mexico)], E-mail: fefo@ucol.mx; Blanno, Omar [Facultad de Ciencias Fisico-Matematicas, BUAP Apdo. Postal 1364, C.P. 72000 Puebla, Pue (Mexico)], E-mail: pos00625@alumnos.fcfm.buap.mx; Diaz-Cruz, J. Lorenzo [Dual CP Institute of High Energy Physics (Mexico); Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima (Mexico); Facultad de Ciencias Fisico-Matematicas, BUAP Apdo. Postal 1364, C.P. 72000 Puebla, Pue (Mexico)], E-mail: lorenzo.diaz@fcfm.buap.mx

    2008-02-14

    We present and explore the Higgs physics of a model that in addition to the Standard Model fields includes a lepton number violating singlet scalar field. Based on the fact that the only experimental data we have so far for physics beyond the Standard Model is that of neutrino physics, we impose a constraint for any addition not to introduce new higher scales. As such, we introduce right-handed neutrinos with an electroweak scale mass. We study the Higgs decay H{yields}{nu}{nu} and show that it leads to different signatures compared to those in the Standard Model, making it possible to detect them and to probe the nature of their couplings.

  4. SN1987A-Neutrino emission from Supernova': in Dynamic universe model of cosmology

    Science.gov (United States)

    Naga Parameswara Gupta, Satyavarapu

    SN1987A-Neutrino emission from supernova before the star bursts' is an important discovery, when viewed from `Dynamic universe model of cosmology' point of view. In OMEG05, we have successfully presented the reasons for calculation error called `missing mass' in an inhomoge-neous, anisotropic and multi-body Dynamic universe Model, where this error is not occurring. But there are some new voices that say about generation of some flavors of neutrinos during Bigbang. We find from SN1987A Neutrino generation covers all flavors. Remaining flavors of Neutrinos are generated from sun and stars. This covers the whole spectrum. This paper covers all these aspects. And other earlier results by Dynamic Universe Model 1. Offers Singularity free solutions 2. Non-collapsing Galaxy structures 3. Solving Missing mass in Galaxies, and it finds reason for Galaxy circular velocity curves. . . . 4. Blue shifted and red shifted Galaxies co-existence. . . 5. Explains the force behind expansion of universe. 6. Explains the large voids and non-uniform matter densities. 7. Explains the Pioneer anomaly 8. Predicts the trajectory of New Horizons satellite. 9 Jeans swindle test 10. Existence of large number of blue shifted Galaxies `SITA Simulations' software was developed about 18 years back for Dynamic Universe Model of Cosmology. It is based on Newtonian physics. It is Classical singularity free N-body tensor solution to the old problem announced by King Oscar II and tried by Poincare in year AD1888 for 133 masses, tested extensively for so many years. This was developed on 486 based PC of those days; the same software was used repeatedly for so many years for solving different Physical problems on Different PCs and Laptops. It is based on Dynamic Universe Model's mathematical back ground.

  5. Pion production models and neutrino factories

    International Nuclear Information System (INIS)

    Collot, Johann; Kirk, Harold G.; Mokhov, Nikolai V.

    2000-01-01

    Scenarios for the building of muon colliders or storage rings suitable for the generation of robust neutrino beams call for the generation of a prodigious quantity of pions. These pions are then conducted into a decay channel where the resulting muon decay products can be collected for cooling and subsequent acceleration. Central to this concept is the design and construction of a target which will be highly efficient in producing pions of both signs while mitigating the absorption of these pions before they decay. This design effort is being facilitated by using two computer codes FLUKA and MARS. We present comparisons of the two computer codes and also present a comparison of these codes with available data

  6. PION PRODUCTION MODELS AND NEUTRINO FACTORIES

    International Nuclear Information System (INIS)

    COLLOT, J.; KIRK, H.G.; MOKHOV, N.V.

    2000-01-01

    Scenarios for the building of muon colliders or storage rings suitable for the generation of robust neutrino beams call for the generation of a prodigious quantity of pions. These pions are then conducted into a decay channel where the resulting muon decay products can be collected for cooling and subsequent acceleration. Central to this concept is the design and construction of a target which will be highly efficient in producing pions of both signs while mitigating the absorption of these pions before they decay. This design effort is being facilitated by using two computer codes FLUKA and MARS. The authors present comparisons of the two computer codes and also present a comparison of these codes with available data

  7. Renormalisation group analysis of single right-handed neutrino dominance

    International Nuclear Information System (INIS)

    King, S.F.; Nimai Singh, N.

    2000-01-01

    We perform a renormalisation group (RG) analysis of neutrino masses and mixing angles in the see-saw mechanism in the minimal supersymmetric standard model with three right-handed neutrinos, including the effects of the heavy neutrino thresholds. We focus on the case that one of the right-handed neutrinos provides the dominant contribution to the 23 block of the light Majorana matrix, causing its determinant to approximately vanish and giving an automatic neutrino mass hierarchy, so-called single right-handed neutrino dominance which may arise from a U(1) family symmetry. In these models radiative corrections can increase atmospheric and solar neutrino mixing by up to about 10% and 5%, respectively, and may help to achieve bi-maximal mixing. Significantly we find that the radiative corrections over the heavy neutrino threshold region are at least as important as those usually considered from the lightest right-handed neutrino down to low energies

  8. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.

    2012-01-01

    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications of po...... of possible sterile neutrinos with O(eV)-masses for cosmology....

  9. The Mystery of Neutrino Mixings

    CERN Document Server

    Altarelli, Guido

    2011-01-01

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

  10. Quark-model calculation of charmed-baryon production by neutrinos

    International Nuclear Information System (INIS)

    Avilez, C.; Kobayashi, T.; Koerner, J.G.

    1978-01-01

    We study the neutrino production of 25 low-lying charmed-baryon resonances in the four-flavor quark model. The mass difference of ordinary and charmed quarks is explicitly taken into account. The quark model is used to determine the spectrum of the charmed-baryon resonances and the q 2 = 0 values of the weak-current transition matrix elements. These transition matrix elements are then continued to spacelike q 2 values by a generalized meson-dominance ansatz for a set of suitably chosen invariant form factors. We find that the production of the L = 1,2 the J/sup P/ = 3/2 - ,5/2 + charm states are dominant. We discuss the sensitivity of our results to various input assumptions, e.g., the ratio of charm-quark mass to ordinary-quark mass. We give differential cross sections, total cross sections, and energy-integrated total cross sections using experimental neutrino fluxes. We conclude that the charmed-baryon production rate can be as large as 3-4% of the total neutrino cross section in a region extending from charm threshold to E approx. = 10 GeV

  11. Sterile neutrino anarchy

    Science.gov (United States)

    Heeck, Julian; Rodejohann, Werner

    2013-02-01

    Lepton mixing, which requires physics beyond the Standard Model, is surprisingly compatible with a minimal, symmetryless and unbiased approach, called anarchy. This contrasts with highly involved flavor symmetry models. On the other hand, hints for light sterile neutrinos have emerged from a variety of independent experiments and observations. If confirmed, their existence would represent a groundbreaking discovery, calling for a theoretical interpretation. We discuss anarchy in the two-neutrino eV-scale seesaw framework. The distributions of mixing angles and masses according to anarchy are in agreement with global fits for the active and sterile neutrino parameters. Our minimal and economical scenario predicts the absence of neutrinoless double beta decay and one vanishing neutrino mass, and can therefore be tested in future experiments.

  12. Experimental Neutrino Physics: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Charles E.; Maricic, Jelena

    2012-09-05

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

  13. Mixed Inert scalar triplet dark matter, radiative neutrino masses and leptogenesis

    Directory of Open Access Journals (Sweden)

    Wen-Bin Lu

    2017-11-01

    Full Text Available The neutral component of an inert scalar multiplet with hypercharge can provide a stable dark matter particle when its real and imaginary parts have a splitting mass spectrum. Otherwise, a tree-level dark-matter-nucleon scattering mediated by the Z boson will be much above the experimental limit. In this paper we focus on a mixed inert scalar triplet dark matter scenario where a complex scalar triplet with hypercharge can mix with another real scalar triplet without hypercharge through their renormalizable coupling to the standard model Higgs doublet. We consider three specified cases that carry most of the relevant features of the full parameter space: (i the neutral component of the real triplet dominates the dark matter particle, (ii the neutral component of the complex triplet dominates the dark matter particle; and (iii the neutral components of the real and complex triplets equally constitute the dark matter particle. Subject to the dark matter relic abundance and direct detection constraint, we perform a systematic study on the allowed parameter space with particular emphasis on the interplay among triplet-doublet terms and gauge interactions. In the presence of these mixed inert scalar triplets, some heavy Dirac fermions composed of inert fermion doublets can be utilized to generate a tiny Majorana neutrino mass term at one-loop level and realize a successful leptogenesis for explaining the cosmic baryon asymmetry.

  14. Proceedings of the 9th workshop on the mass of the electron neutrino

    International Nuclear Information System (INIS)

    Yasumi, Shinjiro

    1984-03-01

    The 9th workshop on the mass of electron neutrinos was held at KEK, Japan. The experimental studies concerning the M-shell of Dy atoms for the measurement of the mass of electron neutrinos were presented at the workshop. The reports included in this proceedings concern windowless Si(Li) detectors, the irradiation technique to make Ho-163 radioactive sources, high purity Ho-163 sources, the M X-ray spectra of rare earth atoms, the study on the M-shell of Dy atoms by using monochromatic X-ray from the KEK PF (Photon Factory), the absolute measurement of photon beam flux, the angular distribution of M X-ray accompanying the photoelectric effect caused by linearly polarized photons, the X-ray spectrum around the 5p to 3s peak accompanying the decay of Ho-163, and the data of nuclear matrix elements of the electron capture decay of Ho-163. The reports presented at the previous workshop are also included in this proceedings. They concern the theoretical calculation of the M X-ray spectrum of Dy, the mass measurement of electron neutrinos, the X-ray spectrum of Ho-163 sources, the amount of Dy-164 contained in Ho-163 samples, and the isotope dilution mass spectrometry. (Kato, T.)

  15. Constraints on lifetime and mass of heavy lepton neutrinos imposed by big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Miyama, Shoken; Sato, Katsuhiko

    1978-01-01

    If there exist massive neutral leptons (heavy neutrinos), they would have been produced in thermal equilibrium in the early stages of the universe. The effects of their presence and decay on the big bang nucleosynthesis are investigated in detail and abundances of the products 4 He, 2 H and 7 Li are compared with the observed cosmic abundances. We have determined a region in the lifetime-mass diagram of the heavy neutrino which should be ruled out in order for the big bang nucleosynthesis not to conflict with observed abundances of the elements. In addition, if a lower limit of the lifetime obtained from the Weinberg-Salam type theory, tau>=6 x 10 7 (1 MeV/m sub(νh)) 5 sec, is assumed, where m sub(νh) is the mass of the heavy neutrino, the mass range of 70 eV< m sub(νh)<10 MeV is ruled out. The other constraints on the mass and the lifetime obtained from astrophysical considerations are also discussed and summarized. (author)

  16. The gross theory model for neutrino-nucleus cross-section

    International Nuclear Information System (INIS)

    Samana, A R; Barbero, C A; Krmpotic, F; Duarte, S B; Dimarco, A J

    2008-01-01

    The nuclear gross theory, originally formulated by Takahashi and Yamada (1969 Prog. Theor. Phys. 41 1470) for the β-decay, is applied to the electronic-neutrino nucleus reactions, employing a more realistic description of the energetics of the Gamow-Teller resonances. The model parameters are gauged from the most recent experimental data, both for β - -decay and electron capture, separately for even-even, even-odd, odd-odd and odd-even nuclei. The numerical estimates for neutrino-nucleus cross-sections agree fairly well with previous evaluations done within the framework of microscopic models. The formalism presented here can be extended to the heavy nuclei mass region, where weak processes are quite relevant, which is of astrophysical interest because of its applications in supernova explosive nucleosynthesis

  17. Neutrinos at the forefront of elementary physics and astrophysics - Slides and abstracts

    International Nuclear Information System (INIS)

    Wark, D.; Cabrera, A.; Clark, K.; Cribier, M.; Rubbia, A.; Schwetz, T.; Hagedorn, C.; Bajc, B.; Thomas, J.; Nakahata, M.; Bravar, S.; Raffelt, G.; Mirizzi, A.; Serpico, P.; Drappeau, S.; Turk-Chieze, S.; Vignaud, D.; Kouchner, A.; Gay, P.; Baerwald, P.; Van Elewyck, V.; Branco, G.; Arbey, A.; Saviano, N.; Cirelli, M.; Verde, L.; Courtois, H.; Mauger, F.; Giunti, C.; Smadja, G.; Gascon, J.; Katsanevas, S.; Autiero, D.

    2014-01-01

    The conference has focused on neutrinos as a bridge between the two words of particle physics and astrophysics/cosmology with 3 main topics: -) the fundamental properties of neutrinos (neutrino masses and oscillations, mass hierarchy, neutrinoless double beta decay, neutrinos as Majorana particles, the search for CP violation in the leptonic sector, hints of physics beyond the standard model, the present experimental scenario and future large size experiments for neutrino oscillations and astro particle physics...); -) Neutrinos in astrophysics (neutrinos from the sun, neutrinos from Supernovae, high energy neutrinos... ); -) Neutrinos in cosmology (measurements of large scale structures, cosmological parameters, nucleosynthesis, dark matter, sterile neutrinos,...). This document is made up of the slides of the presentations and a few abstracts.

  18. Shell-model computed cross sections for charged-current scattering of astrophysical neutrinos off 40Ar

    Science.gov (United States)

    Kostensalo, Joel; Suhonen, Jouni; Zuber, K.

    2018-03-01

    Charged-current (anti)neutrino-40Ar cross sections for astrophysical neutrinos have been calculated. The initial and final nuclear states were calculated using the nuclear shell model. The folded solar-neutrino scattering cross section was found to be 1.78 (23 ) ×10-42cm2 , which is higher than what the previous papers have reported. The contributions from the 1- and 2- multipoles were found to be significant at supernova-neutrino energies, confirming the random-phase approximation (RPA) result of a previous study. The effects of neutrino flavor conversions in dense stellar matter (matter oscillations) were found to enhance the neutrino-scattering cross sections significantly for both the normal and inverted mass hierarchies. For the antineutrino scattering, only a small difference between the nonoscillating and inverted-hierarchy cross sections was found, while the normal-hierarchy cross section was 2-3 times larger than that of the nonoscillating cross section, depending on the adopted parametrization of the Fermi-Dirac distribution. This property of the supernova-antineutrino signal could probably be used to distinguish between the two hierarchies in megaton LAr detectors.

  19. Cosmogenic neutrinos and ultra-high energy cosmic ray models

    Energy Technology Data Exchange (ETDEWEB)

    Aloisio, R.; Petrera, S. [Gran Sasso Science Institute (INFN), L' Aquila (Italy); Boncioli, D.; Grillo, A.F. [INFN/Laboratori Nazionali Gran Sasso, Assergi (Italy); Di Matteo, A. [INFN and Department of Physical and Chemical Sciences, University of L' Aquila, L' Aquila (Italy); Salamida, F., E-mail: aloisio@arcetri.astro.it, E-mail: denise.boncioli@lngs.infn.it, E-mail: armando.dimatteo@aquila.infn.it, E-mail: aurelio.grillo@lngs.infn.it, E-mail: sergio.petrera@aquila.infn.it, E-mail: salamida@ipno.in2p3.fr [Institut de Physique Nucléaire d' Orsay (IPNO), Université Paris 11, CNRS-IN2P3, Orsay (France)

    2015-10-01

    We use an updated version of SimProp, a Monte Carlo simulation scheme for the propagation of ultra-high energy cosmic rays, to compute cosmogenic neutrino fluxes expected on Earth in various scenarios. These fluxes are compared with the newly detected IceCube events at PeV energies and with recent experimental limits at EeV energies of the Pierre Auger Observatory. This comparison allows us to draw some interesting conclusions about the source models for ultra-high energy cosmic rays. We will show how the available experimental observations are almost at the level of constraining such models, mainly in terms of the injected chemical composition and cosmological evolution of sources. The results presented here will also be important in the evaluation of the discovery capabilities of the future planned ultra-high energy cosmic ray and neutrino observatories.

  20. Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen.

    Science.gov (United States)

    Gando, A; Gando, Y; Hachiya, T; Hayashi, A; Hayashida, S; Ikeda, H; Inoue, K; Ishidoshiro, K; Karino, Y; Koga, M; Matsuda, S; Mitsui, T; Nakamura, K; Obara, S; Oura, T; Ozaki, H; Shimizu, I; Shirahata, Y; Shirai, J; Suzuki, A; Takai, T; Tamae, K; Teraoka, Y; Ueshima, K; Watanabe, H; Kozlov, A; Takemoto, Y; Yoshida, S; Fushimi, K; Banks, T I; Berger, B E; Fujikawa, B K; O'Donnell, T; Winslow, L A; Efremenko, Y; Karwowski, H J; Markoff, D M; Tornow, W; Detwiler, J A; Enomoto, S; Decowski, M P

    2016-08-19

    We present an improved search for neutrinoless double-beta (0νββ) decay of ^{136}Xe in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a significant reduction of the ^{110m}Ag contaminant identified in previous searches. Combining the results from the first and second phase, we obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>1.07×10^{26}  yr at 90% C.L., an almost sixfold improvement over previous limits. Using commonly adopted nuclear matrix element calculations, the corresponding upper limits on the effective Majorana neutrino mass are in the range 61-165 meV. For the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.

  1. Proceedings of the 10th workshop on the mass of the electron neutrino

    International Nuclear Information System (INIS)

    Yasumi, Shinjiro

    1985-01-01

    The small meeting on the mass measurement of electron neutrino was held at National Laboratory for High Energy Physics on July 26, 1984. At this meeting, following studies were reported and discussed: 164 Dy irradiation for the third preparation of 163 Ho; pretreatment of 164 Dy 2 O 3 ; Chemical separation of Ho and Dy in 163 Ho source and their determination; x-ray spectrum determination from 163 Ho by means of the window-less Si(Li) detector; mass measurement of electron neutrino by means of M shell electron capture of 163 Ho; a comment on the m sub(νe)-PF experiment; determination of absorption coefficients in the M shell absorption region of Dy; and a report on ν84 international conference (Dortmund). (Nogami, K.)

  2. NeSSiE and sterile neutrinos

    Science.gov (United States)

    Marsella, G.; NESSiE Collaboration

    2015-08-01

    The wonderful frame pinpointed for the 3 standard neutrinos, beautifully adjusted by the Θ13 measurement, left out some relevant questions such as leptonic CP violation, mass values, Dark Matter and anomalies and discrepancies in several neutrino experiment results. The NESSiE collaboration proposes 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.

  3. Bi-Maximal Neutrino Mixing in the MSSM with a Single Right-Handed Neutrino

    CERN Document Server

    Davidson, S.

    1998-01-01

    We discuss neutrino masses in the framework of a minimal extension of the minimal supersymmetric standard model (MSSM) consisting of an additional single right-handed neutrino superfield $N$ with a heavy Majorana mass $M$, which induces a single light see-saw mass $m_{\

  4. Neutrino Oscillations and Non-standard Interactions

    Directory of Open Access Journals (Sweden)

    Yasaman Farzan

    2018-02-01

    Full Text Available Current neutrino experiments are measuring the neutrino mixing parameters with an unprecedented accuracy. The upcoming generation of neutrino experiments will be sensitive to subdominant neutrino oscillation effects that can in principle give information on the yet-unknown neutrino parameters: the Dirac CP-violating phase in the PMNS mixing matrix, the neutrino mass ordering and the octant of θ23. Determining the exact values of neutrino mass and mixing parameters is crucial to test various neutrino models and flavor symmetries that are designed to predict these neutrino parameters. In the first part of this review, we summarize the current status of the neutrino oscillation parameter determination. We consider the most recent data from all solar neutrino experiments and the atmospheric neutrino data from Super-Kamiokande, IceCube, and ANTARES. We also implement the data from the reactor neutrino experiments KamLAND, Daya Bay, RENO, and Double Chooz as well as the long baseline neutrino data from MINOS, T2K, and NOνA. If in addition to the standard interactions, neutrinos have subdominant yet-unknown Non-Standard Interactions (NSI with matter fields, extracting the values of these parameters will suffer from new degeneracies and ambiguities. We review such effects and formulate the conditions on the NSI parameters under which the precision measurement of neutrino oscillation parameters can be distorted. Like standard weak interactions, the non-standard interaction can be categorized into two groups: Charged Current (CC NSI and Neutral Current (NC NSI. Our focus will be mainly on neutral current NSI because it is possible to build a class of models that give rise to sizeable NC NSI with discernible effects on neutrino oscillation. These models are based on new U(1 gauge symmetry with a gauge boson of mass ≲ 10 MeV. The UV complete model should be of course electroweak invariant which in general implies that along with neutrinos, charged

  5. Solar neutrinos and neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-15

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

  6. PREFACE: Nobel Symposium 129 on Neutrino Physics

    Science.gov (United States)

    Bergström, Lars; Botner, Olga; Carlson, Per; Hulth, Per Olof; Ohlsson, Tommy

    2005-01-01

    Nobel Symposium 129 on Neutrino Physics was held at Haga Slott in Enköping, Sweden during August 19 24, 2004. Invited to the symposium were around 40 globally leading researchers in the field of neutrino physics, both experimental and theoretical. In addition to these participants, some 30 local researchers and graduate students participated in the symposium. The dominant theme of the lectures was neutrino oscillations, which after several years were recently verified by results from the Super-Kamiokande detector in Kamioka, Japan and the SNO detector in Sudbury, Canada. Discussion focused especially on effects of neutrino oscillations derived from the presence of matter and the fact that three different neutrinos exist. Since neutrino oscillations imply that neutrinos have mass, this is the first experimental observation that fundamentally deviates from the standard model of particle physics. This is a challenge to both theoretical and experimental physics. The various oscillation parameters will be determined with increased precision in new, specially designed experiments. Theoretical physics is working intensively to insert the knowledge that neutrinos have mass into the theoretical models that describe particle physics. It will probably turn out that the discovery of neutrino oscillations signifies a breakthrough in the description of the very smallest constituents of matter. The lectures provided a very good description of the intensive situation in the field right now. The topics discussed also included mass models for neutrinos, neutrinos in extra dimensions as well as the `seesaw mechanism', which provides a good description of why neutrino masses are so small. Also discussed, besides neutrino oscillations, was the new field of neutrino astronomy. Among the questions that neutrino astronomy hopes to answer are what the dark matter in the Universe consists of and where cosmic radiation at extremely high energies comes from. For this purpose, large neutrino

  7. Dark Energy and Right-Handed Neutrinos

    CERN Document Server

    Barbieri, Riccardo; Oliver, S J; Strumia, A; Barbieri, Riccardo; Hall, Lawrence J.; Oliver, Steven J.; Strumia, Alessandro

    2005-01-01

    We explore the possibility that a CP violating phase of the neutrino mass matrix is promoted to a pseudo-Goldstone-boson field and is identified as the quintessence field for Dark Energy. By requiring that the quintessence potential be calculable from a Lagrangian, and that the extreme flatness of the potential be stable under radiative corrections, we are led to an essentially unique model. Lepton number is violated only by Majorana masses of light, right-handed neutrinos, comparable to the Dirac masses that mix right- with left-handed neutrinos. We outline the rich and constrained neutrino phenomenology that results from this proposal.

  8. Neutrinos in Nuclear Physics

    Energy Technology Data Exchange (ETDEWEB)

    McKeown, Bob [bmck@jlab.org

    2015-06-01

    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.

  9. Solar model uncertainties, MSW analysis, and future solar neutrino experiments

    International Nuclear Information System (INIS)

    Hata, N.; Langacker, P.

    1994-01-01

    Various theoretical uncertainties in the standard solar model and in the Mikheyev-Smirnov-Wolfenstein (MSW) analysis are discussed. It is shown that two methods give consistent estimations of the solar neutrino flux uncertainties: (a) a simple parametrization of the uncertainties using the core temperature and the ncuelar production cross sections; (b) the Monte Carlo method of Bahcall and Ulrich. In the MSW analysis, we emphasize proper treatments of correlations of theoretical uncertainties between flux components and between different detectors, the Earth effect, and multiple solutions in a combined χ 2 procedure. In particular the large-angle solution of the combined observation is allowed at 95% C.L. only when the theoretical uncertainties are included. If their correlations were ignored, the region would be overestimated. The MSW solutions for various standard and nonstandard solar models are also shown. The MSW predictions of the global solutions for the future solar neutrino experiments are given, emphasizing the measurement of the energy spectrum and the day-night effect in Sudbury Neutrino Observatory and Super-Kamiokande to distinguish the two solutions

  10. Standard and nonstandard neutrino properties

    CERN Document Server

    Valle, José W F

    2003-01-01

    I review the interpretation of solar and atmospheric neutrino data in terms neutrino oscillations and describe some ways to account for the required neutrino masses and mixing angles from first principles, both within top down and bottom-up approaches. Non-oscillation phenomena such as beta beta /sub 0 nu / probe the absolute scale of neutrino mass, and if found, would reveal the Majorana nature of neutrinos. Leptonic CP violation induced by "Majorana" phases drop from oscillations but play a role in the leptogenesis scenario for the baryon asymmetry of the Universe. Direct CP tests in oscillation experiments, such as neutrino factories, will be a tough challenge, due to the hierarchical neutrino mass splittings and the smallness of theta /sub 13/ indicated by reactors. The large solar mixing angle theta /sub 12/ offers a way to probe otherwise inaccessible features of supernova physics. Finally, I note that in lowscale models of neutrino mass, one may probe all mixing angles, including the atmospheric theta ...

  11. Accelerator-Based Neutrino Physics: Past, Present and Future

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The study of the neutrino is the study of physics beyond the Standard Model. We now know that the neutrinos have mass and that neutrino mixing occurs causing neutrino flavour to oscillate as neutrinos propagate through space and time. Further, some measurements can be interpreted as hints for new particles known as sterile neutrinos. The measured values of the mixing parameters make it possible that the matter-antimatter (CP) symmetry may be violated through the mixing process. The consequences of observing CP-invariance violation in neutrinos would be profound. To discover CPinvariance violation will require measurements of exquisite precision. Accelerator-based neutrino sources are central to the future programme and advances in technique are required to deliver the “headline” long- and short-baseline experiments and the programmes required to minimise systematic uncertainties. I will explain how measurements made at CERN using the first ever neutrino beams shaped the Standard Model, how the exciting ne...

  12. Neutrino Factory

    CERN Document Server

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

    2014-01-01

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

  13. Nonthermal leptogenesis with almost degenerate superheavy neutrinos

    NARCIS (Netherlands)

    Allahverdi, Rouzbeh; Mazumdar, Anupam

    We present a model with minimal assumptions for nonthermal leptogenesis with almost degenerate superheavy right-handed neutrinos in a supersymmetric setup. In this scenario the gauge singlet inflaton is directly coupled to the right-handed (s)neutrinos with a mass heavier than the inflaton mass.

  14. Properties of neutrinos: Recent results

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1987-01-01

    Recent progress in experimental determinations of the properties of neutrinos is summarized. In particular, the extensive work on direct kinematic measurements of neutrino mass, on neutrino counting and on neutrino oscillations is highlighted. It is concluded that there may already be sufficient information to fix the masses of the neutrinos, but the evidence is still far from convincing. 63 refs., 13 figs

  15. Minimal model for extragalactic cosmic rays and neutrinos

    Science.gov (United States)

    Kachelrieß, M.; Kalashev, O.; Ostapchenko, S.; Semikoz, D. V.

    2017-10-01

    We aim to explain in a unified way the experimental data on ultrahigh-energy cosmic rays (UHECRs) and neutrinos, using a single source class and obeying limits on the extragalactic diffuse gamma-ray background. If UHECRs only interact hadronically with gas around their sources, the resulting diffuse cosmic-ray (CR) flux can be matched well to the observed one, providing at the same time large neutrino fluxes. Since the required fraction of heavy nuclei is, however, rather large, the maxima of air showers in the Earth's atmosphere induced by UHECRs with energies E ≳3 ×1018 eV would be too high. Therefore, additional photohadronic interactions of UHECRs close to the accelerator have to be present, in order to modify the nuclear composition of CRs in a relatively narrow energy interval. We thus include both photon and gas backgrounds and combine the resulting CR spectra with the high-energy part of the Galactic CR fluxes predicted by the escape model. As result, we find a good description of experimental data on the total CR flux, the mean shower maximum depth Xmax and its width r m s (Xmax) in the whole energy range above E ≃1017 eV . The predicted high-energy neutrino flux matches IceCube measurements, while the contribution to the extragalactic diffuse gamma ray background is of order 30%.

  16. Modelling neutrino and gamma-ray fluxes in supernova remnants

    International Nuclear Information System (INIS)

    Ballet, J; Cassam-Chenai, G; Maurin, G; Naumann, C

    2008-01-01

    Supernova remnants (SNRs) are believed to accelerate charged particles by diffusive shock acceleration (DSA) and to produce the majority of galactic cosmic rays, at least up to the 'knee' at 3-10 15 electron volts. In the framework of a hydrodynamic self-similar simulation of the evolution of young supernova remnants, its interaction with the ambient matter as well as the microwave and infrared background is studied. The photon spectra resulting from synchrotron and inverse Compton emission as well as from hadronic processes are calculated, as are the accompanying neutrino fluxes. Applying this method to the particular case of the SNR RXJ-1713, 7-3946, we find that its TeV emission can in principle be explained by pion decay if the ambient density is assumed to grow with increasing distance from the centre. The neutrino flux associated with this hadronic model is of a magnitude that may be detectable by a cubic-kilometre sized deep-sea neutrino telescope in the northern hemisphere. In this poster, a description of the supernova remnant simulation is given together with the results concerning RXJ-1713.

  17. Neutrino sunshine

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    deficit is taken very seriously, and has led to ideas of neutrino oscillations, and oscillation resonances. If the different neutrino varieties - electron, muon and tau - have a mass, then they can oscillate between themselves. A neutrino beam starting off as pure muon-type, for example, would change its composition as it went along. Setting limits on this behaviour is an important objective in neutrino experiments, with 'long baseline' studies - beams covering a long distance between source and detector, playing a vital role. Lincoln Wolfenstein, one of the architects of the new neutrino oscillation scenarios, says 'it is still not clear whether neutrinos have masses or not'. Laboratory experiments try to measure these masses, but so far only upper Unfits have been established. These studies are beginning to reach the limit of their sensitivity and are unlikely to improve drastically. 'But there is indirect evidence,' says Wolfenstein, 'that neutrinos are much lighter.' The solar neutrino problem is really to solar neutrino opportunity,' he continues. Future experiments with gallium and other new neutrino detection techniques, coupled with new high energy neutrino studies, will answer the question

  18. Quantifying the sensitivity of oscillation experiments to the neutrino mass ordering

    Energy Technology Data Exchange (ETDEWEB)

    Blennow, Mattias [Department of Theoretical Physics, School of Engineering Sciences,KTH Royal Institute of Technology, AlbaNova University Center,106 91 Stockholm (Sweden); Coloma, Pilar; Huber, Patrick [Center for Neutrino Physics, Virginia Tech,Blacksburg, VA 24061 (United States); Schwetz, Thomas [Max-Planck-Institut für Kernphysik,Saupfercheckweg 1, 69117 Heidelberg (Germany); Oskar Klein Centre for Cosmoparticle Physics,Department of Physics, Stockholm University, SE-10691 Stockholm (Sweden)

    2014-03-05

    Determining the type of the neutrino mass ordering (normal versus inverted) is one of the most important open questions in neutrino physics. In this paper we clarify the statistical interpretation of sensitivity calculations for this measurement. We employ standard frequentist methods of hypothesis testing in order to precisely define terms like the median sensitivity of an experiment. We consider a test statistic T which in a certain limit will be normal distributed. We show that the median sensitivity in this limit is very close to standard sensitivities based on Δχ{sup 2} values from a data set without statistical fluctuations, such as widely used in the literature. Furthermore, we perform an explicit Monte Carlo simulation of the INO, JUNO, LBNE, NOνA, and PINGU experiments in order to verify the validity of the Gaussian limit, and provide a comparison of the expected sensitivities for those experiments.

  19. Reactor Neutrinos

    Directory of Open Access Journals (Sweden)

    Soo-Bong Kim

    2013-01-01

    Full Text Available We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very recently the most precise determination of the neutrino mixing angle θ13. This paper provides an overview of the upcoming experiments and of the projects under development, including the determination of the neutrino mass hierarchy and the possible use of neutrinos for society, for nonproliferation of nuclear materials, and geophysics.

  20. Neutrino properties from cosmology

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Future, massive large-scale structure survey have been presented and approved.On the theory side, a significant effort has bene devoted to achieve better modeling of small scale clustering that is of cosmological non-linearities. As a result it has become clear that forthcoming cosmological data have enough statitsical power to detect the effect of non-zero neutrino mass (even at the lower mass scale limit imposed by oscillations) and to constrain the absolute neutrino mass scale.Cosmological data can also constrain the numb...

  1. One-dimensional power spectrum and neutrino mass in the spectra of BOSS

    International Nuclear Information System (INIS)

    Borde, Arnaud

    2014-01-01

    large-volume ones. Using a splicing technique, the resolution is further enhanced to reach the equivalent of simulations with 3072 3 = 29 billion particles of each type in a (100 Mpc/h) 3 box size, i.e. a mean mass per gas particle of 1.2x10 5 solar masses. We show that the resulting power spectrum is accurate at the 2% level over the full range from a few Mpc to several tens of Mpc. We explore the effect on the one-dimensional transmitted-flux power spectrum of 4 cosmological parameters (n s , sigma 8 , Omega m ,H 0 ), 2 astrophysical parameters (T 0 , gamma) related to the heating rate of the IGM and the sum of the neutrino masses. By varying the input parameters around a central model chosen to be in agreement with the latest Planck results, we built a grid of simulations that allows the study of the impact on the flux power spectrum of these seven relevant parameters. We improve upon previous studies by not only measuring the effect of each parameter individually, but also probing the impact of the simultaneous variation of each pair of parameters. We thus provide a full second-order expansion, including cross-terms, around our central model. We check the validity of the second-order expansion with independent simulations obtained either with different cosmological parameters or different seeds for the initial condition generation. Finally, a comparison to the one-dimensional Lyman-alpha forest power spectrum obtained in the first part with BOSS data shows an excellent agreement. Eventually, even if there are still some potential biases and systematic errors that need to be studied in our simulation, we performed cosmological fits combining our measurement of the one-dimensional power spectrum and other cosmological probes such as the CMB results provided by Planck. These preliminary results are very encouraging as they lead to some of the tightest cosmological constraints as of today, especially on the sum of the neutrino masses with an upper limit of 0.1 e

  2. A model of spontaneous CP violation and neutrino phenomenology with approximate LμLτ symmetry

    International Nuclear Information System (INIS)

    Adhikary, Biswajit

    2013-01-01

    We introduce a model where CP and Z 2 symmetry violate spontaneously. CP and Z 2 violate spontaneously through a singlet complex scalar S which obtains vacuum expectation value with phase S = Ve iα /2 and this is the only source of CP violation in this model. Low energy CP violation in the leptonic sector is connected to the large scale phase by three generations of left and right handed singlet fermions in the inverse see-saw like structure of model. We have considered approximate LμL τ symmetry to study neutrino phenomenology. Considering two mass square differences and three mixing angles including non zero θ 13 to their experimental 3σ limit, we have restricted the Lagrangian parameters for reasonably small value of L μ L τ symmetry breaking parameters. We have predicted the three masses, Dirac phase and two Majorana phases. We also evaluate CP violating parameter J CP , sum-mass and effective mass parameter involved in neutrino less double beta decay. (author)

  3. Predictions for the neutrino parameters in the minimal gauged U(1){sub L{sub μ-L{sub τ}}} model

    Energy Technology Data Exchange (ETDEWEB)

    Asai, Kento; Nagata, Natsumi [University of Tokyo, Department of Physics, Bunkyo-ku, Tokyo (Japan); Hamaguchi, Koichi [University of Tokyo, Department of Physics, Bunkyo-ku, Tokyo (Japan); University of Tokyo, Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), Kashiwa (Japan)

    2017-11-15

    We study the structure of the neutrino-mass matrix in the minimal gauged U(1){sub L{sub μ-L{sub τ}}} model, where three right-handed neutrinos are added to the Standard Model in order to obtain non-zero masses for the active neutrinos. Because of the U(1){sub L{sub μ-L{sub τ}}} gauge symmetry, the structure of both Dirac and Majorana mass terms of neutrinos is tightly restricted. In particular, the inverse of the neutrino-mass matrix has zeros in the (μ,μ) and (τ,τ) components, namely, this model offers a symmetric realization of the so-called two-zero-minor structure in the neutrino-mass matrix. Due to these constraints, all the CP phases - the Dirac CP phase δ and the Majorana CP phases α{sub 2} and α{sub 3} - as well as the mass eigenvalues of the light neutrinos m{sub i} are uniquely determined as functions of the neutrino mixing angles θ{sub 12}, θ{sub 23}, and θ{sub 13}, and the squared mass differences Δm{sub 21}{sup 2} and Δm{sub 31}{sup 2}. We find that this model predicts the Dirac CP phase δ to be δ ≅ 1.59π-1.70π (1.54π-1.78π), the sum of the neutrino masses to be sum {sub i}m{sub i} ≅ 0.14-0.22 eV (0.12-0.40 eV), and the effective mass for the neutrinoless double-beta decay to be left angle m{sub ββ} right angle ≅ 0.024-0.055 eV (0.017-0.12 eV) at 1σ (2σ) level, which are totally consistent with the current experimental limits. These predictions can soon be tested in future neutrino experiments. Implications for leptogenesis are also discussed. (orig.)

  4. Introduction to massive neutrinos

    International Nuclear Information System (INIS)

    Kayser, B.

    1984-01-01

    We discuss the theoretical ideas which make it natural to expect that neutrinos do indeed have mass. Then we focus on the physical consequences of neutrino mass, including neutrino oscillation and other phenomena whose observation would be very interesting, and would serve to demonstrate that neutrinos are indeed massive. We comment on the legitimacy of comparing results from different types of experiments. Finally, we consider the question of whether neutrinos are their own antiparticles. We explain what this question means, discuss the nature of a neutrino which is its own antiparticles, and consider how one might determine experimentally whether neutrinos are their own antiparticles or not

  5. Astroparticle physics with solar neutrinos

    OpenAIRE

    NAKAHATA, Masayuki

    2011-01-01

    Solar neutrino experiments observed fluxes smaller than the expectations from the standard solar model. This discrepancy is known as the “solar neutrino problem”. Flux measurements by Super-Kamiokande and SNO have demonstrated that the solar neutrino problem is due to neutrino oscillations. Combining the results of all solar neutrino experiments, parameters for solar neutrino oscillations are obtained. Correcting for the effect of neutrino oscillations, the observed neutrino fluxes are consis...

  6. Flavour-symmetric type-II Dirac neutrino seesaw mechanism

    Science.gov (United States)

    Bonilla, Cesar; Lamprea, J. M.; Peinado, Eduardo; Valle, Jose W. F.

    2018-04-01

    We propose a Standard Model extension with underlying A4 flavour symmetry where small Dirac neutrino masses arise from a Type-II seesaw mechanism. The model predicts the "golden" flavour-dependent bottom-tau mass relation, requires an inverted neutrino mass ordering and non-maximal atmospheric mixing angle. Using the latest neutrino oscillation global fit [1] we derive restrictions on the oscillation parameters, such as a correlation between δCP and mνlightest.

  7. Neutrino masses, Baryon asymmetry, dark matter and the moduli problem - A complete framework

    International Nuclear Information System (INIS)

    Kumar, Piyush

    2009-01-01

    Recent developments in string theory have led to 'realistic' string compactifications which lead to moduli stabilization while generating a hierarchy between the Electroweak and Planck scales at the same time. However, this seems to suggest a rethink of our standard notions of cosmological evolution after the end of inflation and before the beginning of BBN. This epoch is crucial for addressing the issues of neutrino masses, baryon asymmetry, Dark Matter (DM) abundance and the moduli (gravitino) problem. We argue that within classes of realistic string compactifications as defined above, there generically exists a light modulus with a mass comparable to that of the gravitino which is typically much smaller than the Hubble parameter during inflation. Therefore, it is destabilized and generates a large late-time entropy when it decays. Thus, all known elegant mechanisms of generating the baryon asymmetry of the Universe in the literature have to take this fact into account. In this work, we find that it is still possible to naturally generate the observed baryon asymmetry of the Universe as well as light left-handed neutrino masses from a period of Affleck-Dine (AD) leptogenesis shortly after the end of inflation, in classes of realistic string constructions with a minimal extension of the MSSM below the unification scale (consisting only of right-handed neutrinos) and satisfying certain microscopic criteria described in the text. The AD mechanism has already been used to generate the baryon asymmetry in the literature; however in this work we have embedded the above mechanism within a framework well motivated from string theory and have tried to describe the epoch from the end of inflation to the beginning of BBN in a complete and self-consistent manner. The consequences of our analysis are as follows. The lightest left-handed neutrino is required to be virtually massless. The moduli (gravitino) problem can be naturally solved in this framework both within gravity

  8. Probing grand unification with fermion masses, neutrino oscillations ...

    Indian Academy of Sciences (India)

    through a spontaneous breaking of the unification symmetryG to the standard model sym- metry G(213), at a very high energy .... Proton decay is studied also for the case of the extended supersymmetric standard model. (ESSM), that has been proposed a few ...... t in accounting for m(ντ. L) (see Ь4); (iv) the agreement of the ...

  9. Neutrino mass, the right-handed interaction and the double beta decay, 2

    International Nuclear Information System (INIS)

    Doi, Masaru; Kotani, Tsuneyuki; Nishiura, Hiroyuki; Okuda, Kazuko; Takasugi, Eiichi.

    1981-01-01

    Based on the formulae for the double β decay obtained in the previous paper, the general properties of 0 + → J + transitions are discussed and the analysis of the experimental data is presented. It is found that, for the two neutrino mode, the 0 + → 0 + transition in the two nucleon (2n)-mechanism dominates over the 0 + → 2 + transition as well as the contribution from the N*-mechanism. For the neutrinoless mode, only the 0 + → 0 + transition in the 2n-mechanism is allowed if there is no right-handed interaction. When the right-handed interaction gives a sizable contribution, the role of the 0 + → 2 + transition becomes as important as the 0 + → 0 + transition in this mode. It is concluded that the experimental data on the ratio of the 128 Te to 130 Te half-lives by Hennecke et al. suggest that neutrinos are Majorana particles, if we take the Vergados estimation of the nuclear matrix elements. Moreover, we find that the weighted average of neutrino masses is around 34 eV if there is no right-handed interaction. (author)

  10. Atmospheric and Solar Neutrinos with a Heavy Singlet

    CERN Document Server

    King, S F

    1998-01-01

    We follow a minimalistic approach to neutrino masses, by introducing a single heavy singlet $N$ into the standard model (or supersymmetric standard model) with a heavy Majorana mass $M$, which couples as a single right-handed neutrino in a Dirac fashion to leptons, and induces a single light see-saw mass $m_{\

  11. The excitement of neutrino physics

    International Nuclear Information System (INIS)

    Agarwalla, Sanjib Kumar

    2017-01-01

    Marvelous world-class experiments involving neutrinos from the Sun, the Earth's atmosphere, nuclear reactors, and accelerators have firmly established neutrino flavor oscillations. This implies that neutrinos have mass and they mix with each other, providing an evidence for physics beyond the Standard Model. The most recent development in this field is the discovery of the smallest lepton mixing angle ?13. This signifies an important breakthrough in validating the standard three-flavor oscillation picture of neutrinos. In the first part of my talk, I will discuss the basics of neutrino oscillation, and identify the fundamental oscillation parameters which govern this phenomenon. Then, we will review the present knowledge about these parameters, and list the remaining fundamental issues which need to be addressed in current and future neutrino oscillation experiments. In the latter half of my talk, I will mention the role of the upcoming large magnetized Iron Calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) facility to explore the Earth's matter effect by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. Finally, I will describe how this experiment is going to play an important role to address some of the outstanding issues in neutrino oscillation physics. (author)

  12. Beyond the New Standard Model in neutrino oscillations

    Indian Academy of Sciences (India)

    We discuss effects of new physics (NP) in neutrino oscillation experiments. Such effects can modify a production neutrino flux, a detection cross-section and a matter transition. As a result, the NP effects change neutrino oscillations both in vacuum and in matter. A relation between the small effects of NP and the oscillation ...

  13. Neutrino mass bounds from neutrinoless double beta-decays and ...

    Indian Academy of Sciences (India)

    2016-01-21

    Jan 21, 2016 ... Assuming the flatness of the Universe, the constraint we can derive from the current observation is < 0.87 eV at 95% confidence level, which is consistent with < 0.68 eV in the flat CDM model without Lyman alpha forest data. In the presence of Lyman- forest data, interacting dark-energy ...

  14. Developments in Neutrino Physics

    CERN Document Server

    González-Garciá, M Concepción

    2003-01-01

    Measurements of various features of the fluxes of atmospheric and solar neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. We review the phenomenology of neutrino oscillations in vacuum and in matter. We present the existing evidence from solar and atmospheric neutrinos as well as the results from laboratory searches, including the final status of the LSND experiment. We describe the theoretical inputs that are used to interpret the experimental results in terms of neutrino oscillations. We derive the allowed ranges for the mass and mixing parameters in three frameworks: First, each set of observations is analyzed separately in a two-neutrino framework; Second, the data from solar and atmospheric neutrinos are analyzed in a three active neutrino framework; Third, the LSND results are added, and the status of accommodating all three signals in the framework of three active and one sterile light neutrinos is presented. We review the theoretical implications ...

  15. Prompt neutrinos from atmospheric charm in the general-mass variable-flavor-number scheme

    Science.gov (United States)

    Benzke, M.; Garzelli, M. V.; Kniehl, B. A.; Kramer, G.; Moch, S.; Sigl, G.

    2017-12-01

    We present predictions for the prompt-neutrino flux arising from the decay of charmed mesons and baryons produced by the interactions of high-energy cosmic rays in the Earth's atmosphere, making use of a QCD approach on the basis of the general-mass variable-flavor-number scheme for the description of charm hadroproduction at NLO, complemented by a consistent set of fragmentation functions. We compare the theoretical results to those already obtained by our and other groups with different theoretical approaches. We provide comparisons with the experimental results obtained by the IceCube Collaboration in two different analyses and we discuss the implications for parton distribution functions.

  16. Sterile neutrino searches via displaced vertices at LHCb

    Science.gov (United States)

    Antusch, Stefan; Cazzato, Eros; Fischer, Oliver

    2017-11-01

    We explore the sensitivity of displaced vertex searches at LHCb for testing sterile neutrino extensions of the Standard Model towards explaining the observed neutrino masses. We derive estimates for the constraints on sterile neutrino parameters from a recently published displaced vertex search at LHCb based on run 1 data. They yield the currently most stringent limit on active-sterile neutrino mixing in the sterile neutrino mass range between 4.5 GeV and 10 GeV. Furthermore, we present forecasts for the sensitivities that could be obtained from the run 2 data and also for the high-luminosity phase of the LHC.

  17. Solar neutrinos; Les neutrinos solaires

    Energy Technology Data Exchange (ETDEWEB)

    Cribier, M. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Laboratoire astroparticule et cosmologie (APC), 75 - Paris (France); Bowles, Th. [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2005-09-15

    Several decades of studies of solar neutrinos lead now to clear indications that the oscillation between {nu}{sub e} produced in the core of the Sun and other flavours ({nu}{sub {mu}} or {nu}{sub {tau}} ) is the correct explanation of the deficit observed by all experiments. This implies that neutrinos are massive, in contradiction with the minimal standard model of particle physics. Moreover, thanks to the SNO (Sudbury neutrino observatory) experiment, we know that solar models built by astrophysicists predict correctly the flux of neutrinos. (authors)

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

    CERN Document Server

    Simkovic, Fedor; Faessler, Amand

    2010-01-01

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

  19. Cosmology based on f(R) gravity admits 1 eV sterile neutrinos.

    Science.gov (United States)

    Motohashi, Hayato; Starobinsky, Alexei A; Yokoyama, Jun'ichi

    2013-03-22

    It is shown that the tension between recent neutrino oscillation experiments, favoring sterile neutrinos with masses of the order of 1 eV, and cosmological data which impose stringent constraints on neutrino masses from the free streaming suppression of density fluctuations, can be resolved in models of the present accelerated expansion of the Universe based on f(R) gravity.

  20. Computation with Inverse States in a Finite Field FPα: The Muon Neutrino Mass, the Unified Strong-Electroweak Coupling Constant, and the Higgs Mass

    International Nuclear Information System (INIS)

    Dai, Yang; Borisov, Alexey B.; Boyer, Keith; Rhodes, Charles K.

    2000-01-01

    The construction of inverse states in a finite field F P α enables the organization of the mass scale with fundamental octets in an eight-dimensional index space that identifies particle states with residue class designations. Conformance with both CPT invariance and the concept of supersymmetry follows as a direct consequence of this formulation. Based on two parameters (P α and g α ) that are anchored on a concordance of physical data, this treatment leads to (1) a prospective mass for the muon neutrino of approximately27.68 meV, (2) a value of the unified strong-electroweak coupling constant α* = (34.26) -1 that is physically defined by the ratio of the electron neutrino and muon neutrino masses, and (3) a see-saw congruence connecting the Higgs, the electron neutrino, and the muon neutrino masses. Specific evaluation of the masses of the corresponding supersymmetric Higgs pair reveals that both particles are superheavy (> 10 18 GeV). No renormalization of the Higgs masses is introduced, since the calculational procedure yielding their magnitudes is intrinsically divergence-free. Further, the Higgs fulfills its conjectured role through the see-saw relation as the particle defining the origin of all particle masses, since the electron and muon neutrino systems, together with their supersymmetric partners, are the generators of the mass scale and establish the corresponding index space. Finally, since the computation of the Higgs masses is entirely determined by the modulus of the field P α , which is fully defined by the large-scale parameters of the universe through the value of the universal gravitational constant G and the requirement for perfect flatness (Omega = 1.0), the see-saw congruence fuses the concepts of mass and space and creates a new unified archetype

  1. Constraints on Dark Energy, Observable-mass Scaling Relations, Neutrino Properties and Gravity from Galaxy Clusters

    DEFF Research Database (Denmark)

    Rapetti Serra, David Angelo

    Using a data set of 238 cluster detections drawn from the ROSAT All-Sky Survey and X-ray follow-up observations from the Chandra X-ray Observatory and/or ROSAT for 94 of those clusters we obtain tight constraints on dark energy, both luminosity-mass and temperature-mass scaling relations, neutrino...... properties and gravity. I will present the novel statistical framework we employed to self-consistently and simultaneously constrain cosmology and observable-mass scaling relations accounting for survey biases, parameter covariances and systematic uncertainties. Allowing the dark energy equation of state...... and the linear growth index to take any constant values, we find no evidence for departures from the standard cosmological paradigm – General Relativity plus a cosmological constant and cold dark matter. I will review in detail our results and demonstrate the power of X-ray cluster studies to constrain both...

  2. Relic Neutrino Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  3. Neutrino factory

    Directory of Open Access Journals (Sweden)

    M. Bogomilov

    2014-12-01

    Full Text Available The properties of the neutrino provide a unique window on physics beyond that described by the standard model. The study of subleading effects in neutrino oscillations, and the race to discover CP-invariance violation in the lepton sector, has begun with the recent discovery that θ_{13}>0. The measured value of θ_{13} is large, emphasizing the need for a facility at which the systematic uncertainties can be reduced to the percent level. The neutrino factory, in which intense neutrino beams are produced from the decay of muons, has been shown to outperform all realistic alternatives and to be capable of making measurements of the requisite precision. Its unique discovery potential arises from the fact that only at the neutrino factory is it practical to produce high-energy electron (antineutrino beams of the required intensity. This paper presents the conceptual design of the neutrino factory accelerator facility developed by the European Commission Framework Programme 7 EUROν Design Study consortium. EUROν coordinated the European contributions to the International Design Study for the Neutrino Factory (the IDS-NF collaboration. The EUROν baseline accelerator facility will provide 10^{21} muon decays per year from 12.6 GeV stored muon beams serving a single neutrino detector situated at a source-detector distance of between 1 500 km and 2 500 km. A suite of near detectors will allow definitive neutrino-scattering experiments to be performed.

  4. The CMB neutrino mass / vacuum energy degeneracy: a simple derivation of the degeneracy slopes.

    Science.gov (United States)

    Sutherland, Will

    2018-03-01

    It is well known that estimating cosmological parameters from cosmic microwave background (CMB) data alone results in a significant degeneracy between the total neutrino mass and several other cosmological parameters, especially the Hubble constant H0 and the matter density parameter Ωm. Adding low-redshift measurements such as baryon acoustic oscillations (BAOs) breaks this degeneracy and greatly improves the constraints on neutrino mass. The sensitivity is surprisingly high, e.g. adding the ˜1 percent measurement of the BAO ratio rs/DV from the BOSS survey leads to a limit Σ mν matter ratio (xν ≡ ων/ωcb) and the shifts in other cosmological parameters. The resulting multipliers are substantially larger than 1: conserving the CMB sound horizon angle requires parameter shifts δln H0 ≈ -2 δxν, δln Ωm ≈ +5 δxν, δln ωΛ ≈ -6.2 δxν, and most notably δωΛ ≈ -14 δων. These multipliers give an intuitive derivation of the degeneracy direction, which agrees well with the numerical likelihood results from the Planck team.

  5. Higgs quartic coupling and neutrino sector evolution in 2UED models

    KAUST Repository

    Abdalgabar, A.

    2014-05-20

    Two compact universal extra-dimensional models are an interesting class of models for different theoretical and phenomenological issues, such as the justification of having three standard model fermion families, suppression of proton decay rate, dark matter parity from relics of the six-dimensional Lorentz symmetry, origin of masses and mixings in the standard model. However, these theories are merely effective ones, with typically a reduced range of validity in their energy scale. We explore two limiting cases of the three standard model generations all propagating in the bulk or all localised to a brane, from the point of view of renormalisation group equation evolutions for the Higgs sector and for the neutrino sector of these models. The recent experimental results of the Higgs boson from the LHC allow, in some scenarios, stronger constraints on the cutoff scale to be placed, from the requirement of the stability of the Higgs potential. 2014 The Author(s).

  6. Working group report: Neutrino and astroparticle physics

    Indian Academy of Sciences (India)

    Keywords. Neutrino oscillation; neutrino mass models; cosmic microwave background radiation; dark energy; branes. ... Effect of threshold corrections on radiative magnification of mixing angles was investigated. The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation ...

  7. Study of neutrino production in the Cannonball model of Gamma ray bursts: possibility of observation of these neutrinos with the Antares neutrinos telescope, and study of the optical background recorded with the prototype sector line; Etude de la production de neutrinos associes aux Sursauts Gamma dans le modele du Boulet de canon: possibilite d'observation de ces neutrinos par le detecteur ANTARES, et etude du bruit de fond optique enregistre par le prototype d'un secteur de ligne

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, S

    2004-09-15

    ANTARES is a future neutrino telescope which will be build at 40 km off the french coast (Toulon), at a 2500 m depth. The interaction of a neutrino with matter produces a muon which emits Cerenkov light while propagating in water. This light is detected with 900 photomultipliers distributed over 12 lines. Gamma ray bursts (GRB) are violent cosmological phenomenon observed once per day. In the Cannonball Model, bursts are produced by the interaction of a jet made of cannonballs (CB) with a supernova remnant (SNR). Forward shocks propagate in the SNR, reverse ones in the CB and neutrinos are produced at the shock fronts. An estimation of the neutrino production is given and is studied over a large parameter range. For a typical GRB, 0.002 to 0.3 v{sub {mu}}, cm{sup -2} can be produced. Depending on the viewing angle, ANTARES could detect 1 to 10 v{sub {mu}} per year in correlation with GRBs. The ambient optical background has been recorded by the ANTARES prototype sector line. The analysis is about the background influence on the detector performance and about the organisms activity which produces it. For example, it appears a 17.6 to 20.4 h periodicity which is compatible with the liquid masses movement imposed by the Coriolis force at the ANTARES latitude. (author)

  8. 50 years of neutrinos

    CERN Document Server

    Goldhaber, M

    1980-01-01

    On December 4 1930, Wolfgang Pauli addressed an "open letter" to Lise Meitner and others attending a physics meeting, suggesting the neutrino as a way out of the difficulties confronted in beta rays research, especially by the existence of a continuous beta spectrum. He proposed a new particle later called the neutrino. The prehistory leading up to Pauli's letter will be reviewed, as well as the later discovery of the electron-neutrino followed by the muon-neutrino. There are now believed to be three different types of neutrino and their anti-particles. Neutrinos have a spin 1/2; but only one spin component has been found in nature: neutrinos go forward as "left-handed" screws and anti-neutrinos as "right-handed" ones. A question still not convincingly resolved today is wether neutrinos have a mass different from zero and, if they do, what consequences this would have for the behaviour of neutrinos and for cosmology.

  9. Confronting the conventional ideas of grand unification with fermion masses, neutrino oscillations and proton decay

    International Nuclear Information System (INIS)

    Pati, J.C.

    2002-01-01

    It is noted that one is now in possession of a set of facts, which may be viewed as the matching pieces of a puzzle; in that all of them can be resolved by just one idea - that is grand unification. These include: (i) the observed family-structure, (ii) quantization of electric charge, (iii) meeting of the three gauge couplings, (iv) neutrino oscillations; in particular the mass squared-difference Δm 2 (ν μ - ν τ ) (suggested by SuperK), (v) the intricate pattern of the masses and mixings of the fermions, including the smallness of V cb and the largeness of θ ν μ ν τ osc , and (vi) the need for B-L as a generator to implement baryogenesis (via leptogenesis). All these pieces fit beautifully together within a single puzzle board framed by supersymmetric unification, based on SO(10) or a string-unified G(224)-symmetry. The two notable pieces of the puzzle still missing, however, are proton decay and supersymmetry. A concrete proposal is presented, within a predictive SO(10)/G(224)- framework, that successfully describes the masses and mixings of all fermions, including the neutrinos - with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which (a) pays special attention to its dependence on the fermion masses, including the superheavy Majorana masses of the right-handed neutrinos, and (b) limits the threshold corrections so as to preserve natural coupling unification. The study updates prior work by Babu, Pati and Wilczek, in the context of both MSSM and its (interesting) variant, the so-called ESSM, by allowing for improved values of the matrix elements and of the short and long-distance renormalization effects. It shows that a conservative upper limit on the proton lifetime is about (1/3 - 2) x 10 34 years, with ν-barK + being the dominant decay mode, and quite possibly μ p +K 0 and e + π 0 being prominent. This in turn strongly suggests that an improvement in the current

  10. Classically conformal radiative neutrino model with gauged B−L symmetry

    Directory of Open Access Journals (Sweden)

    Hiroshi Okada

    2016-09-01

    Full Text Available We propose a classically conformal model in a minimal radiative seesaw, in which we employ a gauged B−L symmetry in the standard model that is essential in order to work the Coleman–Weinberg mechanism well that induces the B−L symmetry breaking. As a result, nonzero Majorana mass term and electroweak symmetry breaking simultaneously occur. In this framework, we show a benchmark point to satisfy several theoretical and experimental constraints. Here theoretical constraints represent inert conditions and Coleman–Weinberg condition. Experimental bounds come from lepton flavor violations (especially μ→eγ, the current bound on the Z′ mass at the CERN Large Hadron Collider, and neutrino oscillations.

  11. Precise measurement of the top quark mass in dilepton decays using optimized neutrino weighting

    Directory of Open Access Journals (Sweden)

    V.M. Abazov

    2016-01-01

    Full Text Available We measure the top quark mass in dilepton final states of tt¯ events in pp¯ collisions at s=1.96 TeV, using data corresponding to an integrated luminosity of 9.7 fb−1 at the Fermilab Tevatron Collider. The analysis features a comprehensive optimization of the neutrino weighting method to minimize the statistical uncertainties. We also improve the calibration of jet energies using the calibration determined in tt¯→lepton+jets events, which reduces the otherwise limiting systematic uncertainty from the jet energy scale. The measured top quark mass is mt=173.32±1.36(stat±0.85(syst GeV.

  12. Study of the atmospheric neutrino oscillations in the Frejus experiment

    International Nuclear Information System (INIS)

    Perdereau, O.

    1989-05-01

    The behavior of atmospheric neutrinos is investigated. It is a zero mass, zero charge and weak interacting particle. The aim of the investigation is to search for non standard phenomena, such as neutrino oscillations. The neutrino theoretical properties are discussed and the physical parameters experimental limits are recalled. The analysis of the approximately 200 events from atmospheric neutrinos observed in Frejus detector is carried out. The results and simulation of neutrino interactions are presented. The data analysis induces to the exclusion of neutrino oscillation hypothesis from some models. Three cases of oscillations involving two neutrino flavors are analyzed. The effect of a third flavor is also taken into account. The present data and those from IMB and Kamiokande experiments are compared. Topics involving investigations on the superposition of a signal and the atmospheric neutrinos are included [fr

  13. Frontiers in neutrino physics - Transparencies

    International Nuclear Information System (INIS)

    Akhmedov, E.; Balantekin, B.; Conrad, J.; Engel, J.; Fogli, G.; Giunti, C.; Espinoza, C.; Lasserre, T.; Lazauskas, R.; Lhuiller, D.; Lindner, M.; Martinez-Pinedo, G.; Martini, M.; McLaughlin, G.; Mirizzi, A.; Pehlivan, Y.; Petcov, S.; Qian, Y.; Serenelli, A.; Stancu, I.; Surman, R.; Vaananen, D.; Vissani, F.; Vogel, P.

    2012-01-01

    This document gathers the slides of the presentations. The purpose of the conference was to discuss the last advances in neutrino physics. The presentations dealt with: -) the measurement of the neutrino velocity, -) neutrino oscillations, -) anomaly in solar models and neutrinos, -) double beta decay, -) self refraction of neutrinos, -) cosmic neutrinos, -) antineutrino spectra from reactors, and -) some aspects of neutrino physics with radioactive ion beams. (A.C.)

  14. Generalized bottom-tau unification, neutrino oscillations and dark matter: Predictions from a lepton quarticity flavor approach

    Science.gov (United States)

    Centelles Chuliá, Salvador; Srivastava, Rahul; Valle, José W. F.

    2017-10-01

    We propose an A4 extension of the Standard Model with a Lepton Quarticity symmetry correlating dark matter stability with the Dirac nature of neutrinos. The flavor symmetry predicts (i) a generalized bottom-tau mass relation involving all families, (ii) small neutrino masses are induced a la seesaw, (iii) CP must be significantly violated in neutrino oscillations, (iv) the atmospheric angle θ23 lies in the second octant, and (v) only the normal neutrino mass ordering is realized.

  15. Generalized bottom-tau unification, neutrino oscillations and dark matter: Predictions from a lepton quarticity flavor approach

    Directory of Open Access Journals (Sweden)

    Salvador Centelles Chuliá

    2017-10-01

    Full Text Available We propose an A4 extension of the Standard Model with a Lepton Quarticity symmetry correlating dark matter stability with the Dirac nature of neutrinos. The flavor symmetry predicts (i a generalized bottom-tau mass relation involving all families, (ii small neutrino masses are induced a la seesaw, (iii CP must be significantly violated in neutrino oscillations, (iv the atmospheric angle θ23 lies in the second octant, and (v only the normal neutrino mass ordering is realized.

  16. Beyond the New Standard Model in neutrino oscillations

    Indian Academy of Sciences (India)

    A relation between the small effects of NP and the oscillation parameters is discussed. It is shown for which ... any coherent neutrino scattering on the background fermions and both scattering amplitudes and neutrino ... parametrized by traditional mixing angles θ12,θ13,θ23 and the CP-breaking angle δ,. |να〉 = 3. ∑ i=1. U∗.

  17. Probing the neutrino mass hierarchy and the 13-mixing with supernovae

    Science.gov (United States)

    Lunardini, Cecilia; Smirnov, Alexei Yu

    2003-06-01

    We consider in detail the effects of the 13-mixing (sin2θ13) and of the type of mass hierarchy/ordering (sign[Δm213]) on neutrino signals from the gravitational collapses of stars. The observables (characteristics of the energy spectra of νe and bar nue events) sensitive to sin2θ13 and sign[Δm213] have been calculated. They include the ratio of average energies of the spectra, rE≡langleErangle/langleĒrangle, the ratio of widths of the energy distributions, rΓ≡Γ/barGamma, the ratios of total numbers of νe and bar nue events at low energies, S, and in the high energy tails, Rtail. We construct and analyse scatter plots which show the predictions for the observables for different intervals of sin2θ13 and signs of Δm213, taking into account uncertainties in the original neutrino spectra, the star density profile, etc. Regions in the space of observables rE, rΓ, S, Rtail exist in which certain mass hierarchy and intervals of sin2θ13 can be identified or discriminated. We elaborate on the method of the high energy tails in the spectra of events. The conditions are formulated for which sin2θ13 can be (i) measured, (ii) restricted from below, (iii) restricted from above. We comment on the possibility to determine sin2θ13 using the time dependence of the signals due to the propagation of the shock wave through the resonance layers of the star. We show that the appearance of the delayed Earth matter effect in one of the channels (νe or bar nue) in combination with the undelayed effect in the other channel will allow us to identify the shock wave appeareance and determine the mass hierarchy.

  18. Degenerate spectrum in the neutrino mass anarchy with Wishart matrices and implications for 0 ν β β and δCP

    Science.gov (United States)

    Jeong, Kwang Sik; Kitajima, Naoya; Takahashi, Fuminobu

    2015-06-01

    We show that a degenerate neutrino mass spectrum can be realized in the neutrino mass anarchy hypothesis, if the neutrino Yukawa and right-handed neutrino mass matrices are given by the Wishart matrix, i.e., products of N ×3 rectangular random matrices, whose eigenvalue distribution tends to degenerate for large N . The mixing angle and charge-parity (CP) phase distributions are determined by either the Haar measure of U(3) or that of SO(3). We study how large N is allowed to be without tension with the observed neutrino mass squared differences and find that the predicted value of me e can be within the reach of future 0 ν β β experiments especially for N on the high side of the allowed range.

  19. Neutrino oscillations in a predictive SUSY GUT

    International Nuclear Information System (INIS)

    Blazek, T.; Raby, S.; Tobe, K.

    1999-01-01

    In this paper we present a predictive SO(10) supersymmetric grand unified theory with the family symmetry U(2)xU(1) which has several nice features. We are able to fit fermion masses and mixing angles, including recent neutrino data, with nine parameters in the charged fermion sector and four in the neutrino sector. The family symmetry plays a preeminent role. (i) The model is ''natural''--we include all terms allowed by the symmetry. It restricts the number of arbitrary parameters and enforces many zeros in the effective mass matrices. (ii) Family symmetry breaking from U(2)xU(1)→U(1)→ nothing generates the family hierarchy. It also constrains squark and slepton mass matrices, thus ameliorating flavor violation resulting from squark and slepton loop contributions. (iii) It naturally gives large angle ν μ -ν τ mixing describing atmospheric neutrino oscillation data and small angle ν e -ν s mixing, consistent with the small mixing angle Mikheyev-Smirnov-Wolfenstein (MSW) solution to solar neutrino data. (iv) Finally, in this paper we assume minimal family symmetry-breaking vacuum expectation values (VEV's). As a result we cannot obtain a three neutrino solution to both atmospheric and solar neutrino oscillations. In addition, the solution discussed here cannot fit liquid scintillation neutrino detector (LSND) data even though this solution requires a sterile neutrino ν s . It is important to note, however, that with nonminimal family symmetry-breaking VEV's, a three neutrino solution is possible with the small mixing angle MSW solution to solar neutrino data and large angle ν μ -ν τ mixing describing atmospheric neutrino oscillation data. In the four neutrino case, nonminimal family VEV's may also permit a solution for LSND. The results with nonminimal family breaking are still under investigation and will be reported in a future paper. (c) 1999 The American Physical Society

  20. Charged-current inclusive neutrino cross sections in the SuperScaling model

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, M. V., E-mail: martin.inrne@gmail.com [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Megias, G. D.; Caballero, J. A. [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41080 Sevilla (Spain); González-Jiménez, R. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Moreno, O.; Donnelly, T. W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Barbaro, M. B. [Dipartimento di Fisica, Università di Torino and INFN, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Moya de Guerra, E.; Udías, J. M. [Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain)

    2016-03-25

    SuperScaling model (SuSA) predictions to neutrino-induced charged-current π{sup +} production in the Δ-resonance region are explored under MiniBooNE experimental conditions. The SuSA charged-current π{sup +} results are in good agreement with data on neutrino flux-averaged double-differential cross sections. The SuSA model for quasielastic scattering and its extension to the pion production region are used for predictions of charged-current inclusive neutrino-nucleus cross sections. Results are also compared with the T2K experimental data for inclusive scattering.

  1. Resonantly produced 7 keV sterile neutrino dark matter models and the properties of Milky Way satellites.

    Science.gov (United States)

    Abazajian, Kevork N

    2014-04-25

    Sterile neutrinos produced through a resonant Shi-Fuller mechanism are arguably the simplest model for a dark matter interpretation of the origin of the recent unidentified x-ray line seen toward a number of objects harboring dark matter. Here, I calculate the exact parameters required in this mechanism to produce the signal. The suppression of small-scale structure predicted by these models is consistent with Local Group and high-z galaxy count constraints. Very significantly, the parameters necessary in these models to produce the full dark matter density fulfill previously determined requirements to successfully match the Milky Way Galaxy's total satellite abundance, the satellites' radial distribution, and their mass density profile, or the "too-big-to-fail problem." I also discuss how further precision determinations of the detailed properties of the candidate sterile neutrino dark matter can probe the nature of the quark-hadron transition, which takes place during the dark matter production.

  2. Impact of Beyond the Standard Model physics in the detection of the Cosmic Neutrino Background

    Science.gov (United States)

    Arteaga, Martín; Bertuzzo, Enrico; Perez-Gonzalez, Yuber F.; Funchal, Renata Zukanovich

    2017-09-01

    We discuss the effect of Beyond the Standard Model charged current interactions on the detection of the Cosmic Neutrino Background by neutrino capture on tritium in a PTOLEMY-like detector. We show that the total capture rate can be substantially modified for Dirac neutrinos if scalar or tensor right-chiral currents, with strength consistent with current experimental bounds, are at play. We find that the total capture rate for Dirac neutrinos, Γ D BSM , can be between 0.3 to 2.2 of what is expected for Dirac neutrinos in the Standard Model, Γ D SM , so that it can be made as large as the rate expected for Majorana neutrinos with only Standard Model interactions. A non-negligible primordial abundance of right-handed neutrinos can only worsen the situation, increasing Γ D BSM by 30 to 90%. On the other hand, if a much lower total rate is measured than what is expected for Γ D SM , it may be a sign of new physics.

  3. A Simplest A4 Model for Tri-Bimaximal Neutrino Mixing

    CERN Document Server

    Altarelli, Guido

    2009-01-01

    We present a see-saw $A_4$ model for Tri-Bimaximal mixing which is based on a very economical flavour symmetry and field content and still possesses all the good features of $A_4$ models. In particular the charged lepton mass hierarchies are determined by the $A_4\\times Z_4$ flavour symmetry itself without invoking a Froggatt-Nielsen U(1) symmetry. Tri-Bimaximal mixing is exact in leading order while all the mixing angles receive corrections of the same order in next-to-the-leading approximation. As a consequence the predicted value of $\\theta_{13}$ is within the sensitivity of the experiments which will take data in the near future. The light neutrino spectrum, typical of $A_4$ see-saw models, with its phenomenological implications, also including leptoproduction, is studied in detail.

  4. Prompt neutrinos from atmospheric charm in the general-mass variable-flavor-number scheme

    International Nuclear Information System (INIS)

    Benzke, M.; Garzelli, M.V.; Kniehl, B.A.; Kramer, G.; Moch, S.; Sigl, G.

    2017-08-01

    We present predictions for the prompt-neutrino flux arising from the decay of charmed mesons and baryons produced by the interactions of high-energy cosmic rays in the Earth's atmosphere, making use of a QCD approach on the basis of the general-mass variable-flavor-number scheme for the description of charm hadroproduction at NLO, complemented by a consistent set of fragmentation functions. We compare the theoretical results to those already obtained by our and other groups with different theoretical approaches. We provide comparisons with the experimental results obtained by the IceCube Collaboration in two different analyses and we discuss the implications for parton distribution functions.

  5. Very low-energy neutrino interactions

    Science.gov (United States)

    Suzuki, Toshio

    2015-05-01

    Neutrino-nucleus reaction cross sections are now evaluated rather accurately by shell-model (SM) or SM+RPA calculations based on recent advances in nuclear structure studies. Due to these achievements, reliable constraints on super-nova neutrino temperatures as well as neutrino oscillation parameters become possible. Supernova neutrino tempeatures are constrained from abundances of elements obtained by using new ν-nucleus reaction cross sections. A possibility of constructing supernova neutrino spectrum from beta-beam measurements is pointed out. Neutrino mass hierarchy and mixing angle θ13 can be determined from abundance ratio of 7Li/11B, which is sensitive to the MSW matter oscillation effects in supernova explosions. Inverted mass hierarchy is shown to be statistically more favored based on a recent analysis of presolar grains. Effects of neutrino-neutrino interactions are also shown to play important roles in r-process nucleosynthesis. Importance and possibilities of direct measurements of ν-induced cross sections on 40Ar and 208Pb are discussed for future supernova neutrino detections. Recent calculations of the cross sections for ν-40Ar are presented. The need for new theoretical evaluations of the cross sections for ν-208Pb is pointed out. Challenges to experiments on coherent elastic scattering are presented.

  6. The neutrino mirror

    International Nuclear Information System (INIS)

    Vannucci, F.

    2003-09-01

    The neutrino is not an elementary particle like others, it is the most stunning of all: the neutrino is undetectable by itself, we have only indirect evidences of its existence, but the neutrino is essential to explain the weak interaction, to understand why matter triumphed over anti-matter just after the Big-bang, or to solve the riddle of the hidden mass of the universe. This book is a popular work dedicated to the neutrino from its discovery in beta decays to the most recent theories such as neutrino oscillations, and via the worldwide experiments dedicated to the study of the neutrinos. (A.C.)

  7. Implementing the correlated fermi gas nuclear model for quasielastic neutrino-nucleus scattering

    Science.gov (United States)

    Tockstein, Jameson

    2017-09-01

    When studying neutrino oscillations an understanding of charged current quasielastic (CCQE) neutrino-nucleus scattering is imperative. This interaction depends on a nuclear model as well as knowledge of form factors. Neutrino experiments, such as MiniBooNE, often use the Relativistic Fermi Gas (RFG) nuclear model. Recently, the Correlated Fermi Gas (CFG) nuclear model was suggested in, based on inclusive and exclusive scattering experiments at JLab. We implement the CFG model for CCQE scattering. In particular, we provide analytic expressions for this implementation that can be used to analyze current and future neutrino CCQE data. This project was supported through the Wayne State University REU program under NSF Grant PHY-1460853 and by the DOE Grant DE-SC0007983.

  8. Same sign dimuon search for heavy majorana mass neutrinos at the CMS experiment at CERN and design studies of a quartz plate calorimeter prototype

    Energy Technology Data Exchange (ETDEWEB)

    Clarida, Warren James [Univ. of Iowa, Iowa City, IA (United States)

    2012-12-01

    This paper consists of two studies: the results of a search for heavy Majorana neutrinos (N) using an event signature defined by two like-sign charged muons and two jets, and the results from studies of a prototype quartz plate calorimeter. The data in the Majorana search correspond to an integrated luminosity of 5.0 fb$^{−1}$ of pp collisions at a centre-of-mass energy of 7 TeV collected with the CMS detector at the Large Hadron Collider. No excess of events are observed beyond the expected standard model background and therefore upper limits are set on the square of the mixing element, $|V_{\\mu N} |$as a function of Majorana neutrino mass. These are the first direct upper limits on the heavy Majorana-neutrino mixing for m$_N$ > 90 GeV . The second part of this thesis is the results of performance tests of a 20-layer quartz plate calorimeter prototype. The calorimeter prototype was tested at the CERN H2 area in hadronic and electromagnetic configurations, at various en ergies of pion and electron beams. The beam test and simulation results of this prototype are reported.

  9. Same sign dimuon search for heavy majorana mass neutrinos at the CMS experiment at CERN and design studies of a quartz plate calorimeter prototype

    CERN Document Server

    Clarida, Warren James

    2012-01-01

    This paper consists of two studies: the results of a search for heavy Majorana neutrinos (N) using an event signature defined by two like-sign charged muons and two jets, and the results from studies of a prototype quartz plate calorimeter. The data in the Majorana search correspond to an integrated luminosity of 5.0 fb$^{−1}$ of pp collisions at a centre-of-mass energy of 7 TeV collected with the CMS detector at the Large Hadron Collider. No excess of events are observed beyond the expected standard model background and therefore upper limits are set on the square of the mixing element, $|V_{\\mu N} |$as a function of Majorana neutrino mass. These are the first direct upper limits on the heavy Majorana-neutrino mixing for m$_N$ > 90 GeV . The second part of this thesis is the results of performance tests of a 20-layer quartz plate calorimeter prototype. The calorimeter prototype was tested at the CERN H2 area in hadronic and electromagnetic configurations, at various en ergies of pion and electron beams. Th...

  10. Probing neutrino and Higgs sectors in SU(2){sub 1} x SU(2){sub 2} x U(1){sub Y} model with lepton-flavor non-universality

    Energy Technology Data Exchange (ETDEWEB)

    Hue, L.T. [Duy Tan University, Institute of Research and Development, Da Nang City (Viet Nam); Vietnam Academy of Science and Technology, Institute of Physics, Hanoi (Viet Nam); Arbuzov, A.B. [Joint Institute for Nuclear Researches, Bogoliubov Laboratory for Theoretical Physics, Dubna (Russian Federation); Ngan, N.T.K. [Cantho University, Department of Physics, Cantho (Viet Nam); Vietnam Academy of Science and Technology, Graduate University of Science and Technology, Hanoi (Viet Nam); Long, H.N. [Ton Duc Thang University, Theoretical Particle Physics and Cosmology Research Group, Ho Chi Minh City (Viet Nam); Ton Duc Thang University, Faculty of Applied Sciences, Ho Chi Minh City (Viet Nam)

    2017-05-15

    The neutrino and Higgs sectors in the SU(2){sub 1} x SU(2){sub 2} x U(1){sub Y} model with lepton-flavor non-universality are discussed. We show that active neutrinos can get Majorana masses from radiative corrections, after adding only new singly charged Higgs bosons. The mechanism for the generation of neutrino masses is the same as in the Zee models. This also gives a hint to solving the dark matter problem based on similar ways discussed recently in many radiative neutrino mass models with dark matter. Except the active neutrinos, the appearance of singly charged Higgs bosons and dark matter does not affect significantly the physical spectrum of all particles in the original model. We indicate this point by investigating the Higgs sector in both cases before and after singly charged scalars are added into it. Many interesting properties of physical Higgs bosons, which were not shown previously, are explored. In particular, the mass matrices of charged and CP-odd Higgs fields are proportional to the coefficient of triple Higgs coupling μ. The mass eigenstates and eigenvalues in the CP-even Higgs sector are also presented. All couplings of the SM-like Higgs boson to normal fermions and gauge bosons are different from the SM predictions by a factor c{sub h}, which must satisfy the recent global fit of experimental data, namely 0.995 < vertical stroke c{sub h} vertical stroke < 1. We have analyzed a more general diagonalization of gauge boson mass matrices, then we show that the ratio of the tangents of the W-W{sup '} and Z-Z{sup '} mixing angles is exactly the cosine of the Weinberg angle, implying that number of parameters is reduced by 1. Signals of new physics from decays of new heavy fermions and Higgs bosons at LHC and constraints of their masses are also discussed. (orig.)

  11. Probing neutrino and Higgs sectors in { SU(2) }_1 × { SU(2) }_2 × { U(1) }_Y model with lepton-flavor non-universality

    Science.gov (United States)

    Hue, L. T.; Arbuzov, A. B.; Ngan, N. T. K.; Long, H. N.

    2017-05-01

    The neutrino and Higgs sectors in the { SU(2) }_1 × { SU(2) }_2 × { U(1) }_Y model with lepton-flavor non-universality are discussed. We show that active neutrinos can get Majorana masses from radiative corrections, after adding only new singly charged Higgs bosons. The mechanism for the generation of neutrino masses is the same as in the Zee models. This also gives a hint to solving the dark matter problem based on similar ways discussed recently in many radiative neutrino mass models with dark matter. Except the active neutrinos, the appearance of singly charged Higgs bosons and dark matter does not affect significantly the physical spectrum of all particles in the original model. We indicate this point by investigating the Higgs sector in both cases before and after singly charged scalars are added into it. Many interesting properties of physical Higgs bosons, which were not shown previously, are explored. In particular, the mass matrices of charged and CP-odd Higgs fields are proportional to the coefficient of triple Higgs coupling μ . The mass eigenstates and eigenvalues in the CP-even Higgs sector are also presented. All couplings of the SM-like Higgs boson to normal fermions and gauge bosons are different from the SM predictions by a factor c_h, which must satisfy the recent global fit of experimental data, namely 0.995<|c_h|<1. We have analyzed a more general diagonalization of gauge boson mass matrices, then we show that the ratio of the tangents of the W-W' and Z-Z' mixing angles is exactly the cosine of the Weinberg angle, implying that number of parameters is reduced by 1. Signals of new physics from decays of new heavy fermions and Higgs bosons at LHC and constraints of their masses are also discussed.

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

    Science.gov (United States)

    Berlin, Asher

    2016-12-02

    We consider a class of models involving interactions between ultralight scalar dark matter and standard model neutrinos. Such couplings modify the neutrino mass splittings and mixing angles to include additional components that vary in time periodically with a frequency and amplitude set by the mass and energy density of the dark matter. Null results from recent searches for anomalous periodicities in the solar neutrino flux strongly constrain the dark matter-neutrino coupling to be orders of magnitude below current and projected limits derived from observations of the cosmic microwave background.

  13. Solar neutrino oscillations

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1993-01-01

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

  14. Solar Neutrinos

    OpenAIRE

    Pallavicini, Marco

    2009-01-01

    The status of solar neutrino experiments and their implications for both nonstandard astrophysics ({\\it e.g.,} cool sun models) and nonstandard neutrino properties ({\\it e.g.,} MSW conversions) are discussed. Assuming that all of the experiments are correct, the relative rates observed by Kamiokande and Homestake are hard to account for by a purely astrophysical solution, while MSW conversions can describe all of the data. Assuming the standard solar model, there are two allowed regions for M...

  15. Solar Neutrinos

    OpenAIRE

    Antonelli, V.; Miramonti, L.; Peña Garay, Carlos; Serenelli, A.

    2013-01-01

    The study of solar neutrinos has given since ever a fundamental contribution both to astroparticle and to elementary particle physics, offering an ideal test of solar models and offering at the same time relevant indications on the fundamental interactions among particles. After reviewing the striking results of the last two decades, which were determinant to solve the long standing solar neutrino puzzle and refine the Standard Solar Model, we focus our attention on the more recent results in...

  16. Characterization of the ^{163}Ho Electron Capture Spectrum: A Step Towards the Electron Neutrino Mass Determination.

    Science.gov (United States)

    Ranitzsch, P C-O; Hassel, C; Wegner, M; Hengstler, D; Kempf, S; Fleischmann, A; Enss, C; Gastaldo, L; Herlert, A; Johnston, K

    2017-09-22

    The isotope ^{163}Ho is in many ways the best candidate to perform experiments to investigate the value of the electron neutrino mass. It undergoes an electron capture process to ^{163}Dy with an energy available to the decay, Q_{EC}, of about 2.8 keV. According to the present knowledge, this is the lowest Q_{EC} value for such transitions. Here we discuss a newly obtained spectrum of ^{163}Ho, taken by cryogenic metallic magnetic calorimeters with ^{163}Ho implanted in the absorbers and operated in anticoincident mode for background reduction. For the first time, the atomic deexcitation of the ^{163}Dy daughter atom following the capture of electrons from the 5s shell in ^{163}Ho, the OI line, was observed with a calorimetric measurement. The peak energy is determined to be 48 eV. In addition, a precise determination of the energy available for the decay Q_{EC}=(2.858±0.010_{stat}±0.05_{syst})  keV was obtained by analyzing the intensities of the lines in the spectrum. This value is in good agreement with the measurement of the mass difference between ^{163}Ho and ^{163}Dy obtained by Penning-trap mass spectrometry, demonstrating the reliability of the calorimetric technique.

  17. Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

    CERN Multimedia

    2002-01-01

    The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

  18. Characterization of the 163Ho Electron Capture Spectrum: A Step Towards the Electron Neutrino Mass Determination

    Science.gov (United States)

    Ranitzsch, P. C.-O.; Hassel, C.; Wegner, M.; Hengstler, D.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2017-09-01

    The isotope 163Ho is in many ways the best candidate to perform experiments to investigate the value of the electron neutrino mass. It undergoes an electron capture process to 163Dy with an energy available to the decay, QEC, of about 2.8 keV. According to the present knowledge, this is the lowest QEC value for such transitions. Here we discuss a newly obtained spectrum of 163Ho, taken by cryogenic metallic magnetic calorimeters with 163Ho implanted in the absorbers and operated in anticoincident mode for background reduction. For the first time, the atomic deexcitation of the 163Dy daughter atom following the capture of electrons from the 5 s shell in 163Ho, the OI line, was observed with a calorimetric measurement. The peak energy is determined to be 48 eV. In addition, a precise determination of the energy available for the decay QEC=(2.858 ±0.01 0stat±0.0 5syst) keV was obtained by analyzing the intensities of the lines in the spectrum. This value is in good agreement with the measurement of the mass difference between 163Ho and 163Dy obtained by Penning-trap mass spectrometry, demonstrating the reliability of the calorimetric technique.

  19. Solar neutrinos

    International Nuclear Information System (INIS)

    Schatzman, E.

    1983-01-01

    The solar energy is produced by a series of nuclear reactions taking place in the deep interior of the sun. Some of these reactions produce neutrinos which may be detected, the proper detection system being available. The results of the Davis experiment (with 37 Cl) are given, showing a deficiency in the solar neutrino flux. The relevant explanation is either a property of the neutrino or an important change in the physics of the solar models. The prospect of a new experiment (with 71 Ga) is important as it will decide which of the two explanations is correct [fr

  20. Neutrino Physics at Drexel

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Charles [Drexel Univ., Philadelphia, PA (United States); Dolinski, Michelle [Drexel Univ., Philadelphia, PA (United States); Neilson, Russell [Drexel Univ., Philadelphia, PA (United States)

    2017-07-11

    Our primary goal is to improve the understanding of the properties and interactions of neutrinos. We are pursuing this by means of the DUNE long-baseline and PROSPECT short-baseline neutrino experiments. For DUNE, a neutrino beam from Fermilab will be detected at the SURF facility in South Dakota, with the aim of determining the neutrino mass hierarchy (the mass ordering of neutrino flavors), and a measurement or limit on CP-violation via neutrinos. Our near-term experimental goal is to improve the characterization of the neutrino beam by measurements of muons produced as a byproduct of neutrino beam generation, to quantify the beam composition and flux. The short-range neutrino program has the aim of using the HFIR reactor at Oak Ridge as a neutrino source, with a detector placed nearby to find if there are short-distance oscillations to sterile neutrino flavors, and to resolve the 'reactor neutrino spectral anomaly' which has shown up as an unexplained 'bump' in the neutrino energy spectrum in recent experiments.

  1. Again on neutrino oscillations

    International Nuclear Information System (INIS)

    Bilenky, S.M.; Pontecorvo, B.

    1976-01-01

    The general case is treated of a weak interaction theory in which a term violating lepton charges is present. In such a scheme the particles with definite masses are Majorana neutrinos (2N if in the weak interaction participate N four-component neutrinos). Neutrino oscillations are discussed and it is shown that the minimum average intensity at the earth of solar neutrinos is 1/2N of the intensity expected when oscillations are absent

  2. Search for neutrinos from annihilation of captured low-mass dark matter particles in the sun by super-kamiokande.

    Science.gov (United States)

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

    2015-04-10

    Super-Kamiokande (SK) can search for weakly interacting massive particles (WIMPs) by detecting neutrinos produced from WIMP annihilations occurring inside the Sun. In this analysis, we include neutrino events with interaction vertices in the detector in addition to upward-going muons produced in the surrounding rock. Compared to the previous result, which used the upward-going muons only, the signal acceptances for light (few-GeV/c^{2}-200-GeV/c^{2}) WIMPs are significantly increased. We fit 3903 days of SK data to search for the contribution of neutrinos from WIMP annihilation in the Sun. We found no significant excess over expected atmospheric-neutrino background and the result is interpreted in terms of upper limits on WIMP-nucleon elastic scattering cross sections under different assumptions about the annihilation channel. We set the current best limits on the spin-dependent WIMP-proton cross section for WIMP masses below 200  GeV/c^{2} (at 10  GeV/c^{2}, 1.49×10^{-39}  cm^{2} for χχ→bb[over ¯] and 1.31×10^{-40}  cm^{2} for χχ→τ^{+}τ^{-} annihilation channels), also ruling out some fraction of WIMP candidates with spin-independent coupling in the few-GeV/c^{2} mass range.

  3. Cosmological and astrophysical implications of sterile neutrinos

    Science.gov (United States)

    Petraki, Kalliopi

    The discovery of neutrino masses suggests that the Standard Model should be supplemented with new gauge-singlet fermions, often called sterile neutrinos. The interplay among the new couplings introduced in the Standard Model can accommodate the neutrino oscillation data for a variety of choices: the new particles can be extremely heavy and practically unobservable, or they can be light, in which case they can solve several long-standing puzzles. It has been shown, for example, that sterile neutrinos in some range of masses can account for dark matter, their emission from a supernova can explain pulsar kicks, arid their decays can play an important role in the formation of the first stars. Though indirect, these clues indicate that sterile neutrinos can be the minimal solution to a variety of unsolved problems. This emphasizes the importance of investigating further the consequences of these new degrees of freedom for cosmology and astrophysics. In this dissertation, I explore the possible role of sterile neutrinos of different mass scales in some cosmological and astrophysical phenomena. A minimal extension of the Higgs sector of the Standard Model, with a gauge- singlet boson coupled to sterile neutrinos, can provide a consistent framework for the theory of neutrino masses, and can produce a relic population of keV sterile neutrinos via decays of the singlet Higgs. The latter can account for the dark matter of the universe. The mechanism operates around the electroweak scale, and has interesting consequences for the electroweak phase transition. Relic sterile neutrinos produced via decays at the electroweak scale constitute colder dark matter than those produced via other previously suggested mechanisms. The primordial thermal content of dark matter has important implications for the formation of cosmic structures, such as clusters and galaxies. The assessment of the relevant properties suggests that sterile neutrinos produced at the electroweak scale are a

  4. Molybdenum solar neutrino experiment

    International Nuclear Information System (INIS)

    Wolfsberg, K.; Cowan, G.A.; Bryant, E.A.

    1984-01-01

    The goal of the molybdenum solar neutrino experiment is to deduce the 8 B solar neutrino flux, averaged over the past several million years, from the concentration of 98 Tc in a deeply buried molybdenum deposit. The experiment is important to an understanding of stellar processes because it will shed light on the reason for the discrepancy between theory and observation of the chlorine solar neutrino experiment. Possible reasons for the discrepancy may lie in the properties of neutrinos (neutrino oscillations or massive neutrinos) or in deficiencies of the standard solar model. The chlorine experiment only measures the 8 B neutrino flux in current times and does not address possible temporal variations in the interior of the sun, which are also not considered in the standard model. In the molybdenum experiment, we plan to measure 98 Tc (4.2 Myr), also produced by 8 B neutrinos, and possibly 97 Tc (2.6 Myr), produced by lower energy neutrinos

  5. Neutrino dark energy. Revisiting the stability issue

    International Nuclear Information System (INIS)

    Eggers Bjaelde, O.; Hannestad, S.; Schrempp, L.; Tocchini-Valentini, D.

    2007-05-01

    A coupling between a light scalar field and neutrinos has been widely discussed as a mechanism for linking (time varying) neutrino masses and the present energy density and equation of state of dark energy. However, it has been pointed out that the viability of this scenario in the non-relativistic neutrino regime is threatened by the strong growth of hydrodynamic perturbations associated with a negative adiabatic sound speed squared. In this paper we revisit the stability issue in the framework of linear perturbation theory in a model independent way. The criterion for the stability of a model is translated into a constraint on the scalar-neutrino coupling, which depends on the ratio of the energy densities in neutrinos and cold dark matter. We illustrate our results by providing meaningful examples both for stable and unstable models. (orig.)

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

    CERN Document Server

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

    2017-04-27

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-01

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

  8. Neutrino clouds

    International Nuclear Information System (INIS)

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

    1997-01-01

    We consider the possibility that neutrinos are coupled very weakly to an extremely light scalar boson. We first analyze the simple problem of one generation of neutrino and show that, for ranges of parameters that are allowed by existing data, such a system can have serious consequences for the evolution of stars and could impact precision laboratory measurements. We discuss the extension to more generations and show that the general conclusion remains viable. Finally, we note that, should such a scalar field be present, experiments give information about effective masses, not the masses that arise in unified field theories. (authors). 23 refs., 9 figs

  9. Confronting the Conventional Ideas of Grand Unification with Fermion Masses, Neutrino Oscillations and Proton Decay

    Energy Technology Data Exchange (ETDEWEB)

    Pati, Jogesh C.

    2002-05-10

    It is noted that one is now in possession of a set of facts, which may be viewed as the matching pieces of a puzzle; in that all of them can be resolved by just one idea--that is grand unification. These include (i) the observed family-structure, (ii) quantization of electric charge, (iii) the meeting of the three gauge couplings, (iv) neutrino oscillations [in particular the value {Delta}m{sup 2}({nu}{sub {mu}}-{nu}{sub {tau}}), suggested by SuperK], (v) the intricate pattern of the masses and mixings of the fermions, including the smallness of V{sub cb} and the largeness of {theta}{sub {nu}{sub {mu}}{nu}{sub {tau}}}{sup osc}, and (vi) the need for B-L as a generator to implement baryogenesis (via leptogenesis). All these pieces fit beautifully together within a single puzzle board framed by supersymmetric unification, based on either SO(10) or a string-unified G(224)-symmetry. The two notable pieces of the puzzle still missing, however, are proton decay and supersymmetry. A concrete proposal is presented within a predictive SO(10)/G(224)-framework that successfully describes the masses and mixings of all fermions, including the neutrinos--with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which (a) pays special attention to its dependence on the fermion masses, and (b) limits the threshold corrections so as to preserve natural coupling unification. The study updates prior work by Babu, Pati and Wilczek, in the context of both MSSM and its (interesting) variant, the so-called ESSM, by allowing for improved values of the matrix elements and of the short- and long-distance renormalization effects. It shows that a conservative upper limit on the proton lifetime is about (1/3-2) x 10{sup 34} years, with {bar {nu}}K{sup +} being the dominant decay mode, and quite possibly {mu}{sup +}K{sup 0} and e{sup +}{pi}{sup 0} being prominent. This in turn strongly suggests that an improvement in the

  10. A model for large non-standard interactions of neutrinos leading to the LMA-Dark solution

    Directory of Open Access Journals (Sweden)

    Yasaman Farzan

    2015-09-01

    Full Text Available It is well-known that in addition to the standard LMA solution to solar anomaly, there is another solution called LMA-Dark which requires Non-Standard Interactions (NSI with effective couplings as large as the Fermi coupling. Although this solution satisfies all the bounds from various neutrino oscillation observations and even provides a better fit to low energy solar neutrino spectrum, it is not as popular as the LMA solution mainly because no model compatible with the existing bounds has been so far constructed to give rise to this solution. We introduce a model that provides a foundation for such large NSI with strength and flavor structure required for the LMA-Dark solution. This model is based on a new U(1′ gauge interaction with a gauge boson of mass ∼10 MeV under which quarks as well as the second and third generations of leptons are charged. We show that observable effects can appear in the spectrum of supernova and high energy cosmic neutrinos. Our model predicts a new contribution to the muon magnetic dipole moment and new rare meson decay modes.

  11. Signatures of extra dimensional sterile neutrinos

    Directory of Open Access Journals (Sweden)

    Werner Rodejohann

    2014-10-01

    Full Text Available We study a large extra dimension model with active and sterile Dirac neutrinos. The sterile neutrino masses stem from compactification of an extra dimension with radius R and are chosen to have masses around eV or keV, in order to explain short-baseline anomalies or act as warm dark matter candidates. We study the effect of the sterile neutrino Kaluza–Klein tower in short-baseline oscillation experiments and in the beta spectrum as measurable by KATRIN-like experiments.

  12. Model-dependent high-energy neutrino flux from gamma-ray bursts.

    Science.gov (United States)

    Zhang, Bing; Kumar, Pawan

    2013-03-22

    The IceCube Collaboration recently reported a stringent upper limit on the high energy neutrino flux from gamma-ray bursts (GRBs), which provides a meaningful constraint on the standard internal shock model. Recent broadband electromagnetic observations of GRBs also challenge the internal shock paradigm for GRBs, and some competing models for γ-ray prompt emission have been proposed. We describe a general scheme for calculating the GRB neutrino flux, and compare the predicted neutrino flux levels for different models. We point out that the current neutrino flux upper limit starts to constrain the standard internal shock model. The dissipative photosphere models are also challenged if the cosmic ray luminosity from GRBs is at least 10 times larger than the γ-ray luminosity. If the neutrino flux upper limit continues to go down in the next few years, then it would suggest the following possibilities: (i) the photon-to-proton luminosity ratio in GRBs is anomalously high for shocks, which may be achieved in some dissipative photosphere models and magnetic dissipation models; or (ii) the GRB emission site is at a larger radius than the internal shock radius, as expected in some magnetic dissipation models such as the internal collision-induced magnetic reconnection and turbulence model.

  13. Charged Cosmic Rays and Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kachelrieß, M.

    2013-04-15

    High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test “vanilla” models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at “Neutrino 2012”.

  14. Neutrino cosmology

    CERN Document Server

    Lesgourgues, Julien; Miele, Gennaro; Pastor, Sergio

    2013-01-01

    The role that neutrinos have played in the evolution of the Universe is the focus of one of the most fascinating research areas that has stemmed from the interplay between cosmology, astrophysics and particle physics. In this self-contained book, the authors bring together all aspects of the role of neutrinos in cosmology, spanning from leptogenesis to primordial nucleosynthesis, their role in CMB and structure formation, to the problem of their direct detection. The book starts by guiding the reader through aspects of fundamental neutrino physics, such as the standard cosmological model and the statistical mechanics in the expanding Universe, before discussing the history of neutrinos in chronological order from the very early stages until today. This timely book will interest graduate students and researchers in astrophysics, cosmology and particle physics, who work with either a theoretical or experimental focus.

  15. Ghost basis for neutrino

    International Nuclear Information System (INIS)

    Novello, M.

    1976-07-01

    A class of solutions of DIRAC'S equation in gravitational fields for ghost neutrinos is given. Comments are restricted to the neutrino cosmological model recently found by M. Novello e I.D. Soares [pt

  16. Can a open-quote open-quote natural close-quote close-quote three-generation neutrino mixing scheme satisfy everything?

    International Nuclear Information System (INIS)

    Cardall, C.Y.; Fuller, G.M.

    1996-01-01

    We examine the potential for a open-quote open-quote natural close-quote close-quote three-neutrino mixing scheme to satisfy available data and astrophysical arguments. By open-quote open-quote natural close-quote close-quote we mean no sterile neutrinos, and a neutrino mass hierarchy similar to that of the charged leptons. We seek to satisfy (or solve) (1) accelerator and reactor neutrino oscillation constraints, including LSND, (2) the atmospheric muon neutrino deficit problem, (3) the solar neutrino problem, (4) r-process nucleosynthesis in neutrino-heated supernova ejecta, and (5) cold+hot dark matter models. We argue that putative supernova r-process nucleosynthesis bounds on two-neutrino flavor mixing can be applied directly to three-neutrino mixing in the case where one vacuum neutrino mass eigenvalue difference is dominated by the others. We show that in this open-quote open-quote one mass scale dominance close-quote close-quote limit, a natural three-neutrino oscillation solution meeting all the above constraints exists only if the atmospheric neutrino data and the LSND data can be explained with one neutrino mass difference. In this model, an explanation for the solar neutrino data can be effected by employing the other independent neutrino mass difference. Such a solution is only marginally allowed by the current data, and proposed long-baseline neutrino oscillation experiments can definitively rule it out. If it were ruled out, the simultaneous solution of the above constraints by neutrino oscillations would then require sterile neutrinos and/or a neutrino mass hierarchy of a different nature than that of the charged leptons. copyright 1996 The American Physical Society

  17. Search for Muon neutrino → Tau neutrino oscillations motivation and feasibility

    International Nuclear Information System (INIS)

    Zacek, V.

    1988-01-01

    Theoretical prejudices derived from solar-neutrino matter oscillations and assumptions of neutrino mass hierarchies suggest, that neutrino-oscillations are observable in laboratory with mass parameters of Δm 2 = 10 -3 -10 4 eV 2 . In particular Muon neutrino → Tau neutrino appearance searches at accelerators seem strongly motivated

  18. Neutrino physics present and future

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    Our understanding of neutrinos has been revolutionized by the discovery that they have nonzero masses and very large mixing. We will explain the phenomenology of massive neutrinos, including neutrino oscillation in vacuum and in matter, and the physics of neutrinos that are their own antiparticles. We will review the evidence for neutrino masses and mixing, and summarize what has been learned about the neutrinos so far. Identifying the very interesting open questions raised by the discovery of neutrino mass, we will discuss how these questions may be answered through future experiments. Finally, we will consider the possibility that CP violation by neutrinos is the key to understanding the matter-antimatter asymmetry of the universe, and discuss the see-saw theory of why neutrino masses are so tiny.

  19. Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Bezrukov, F. [The University of Manchester, School of Physics and Astronomy, Oxford Road, Manchester M13 9PL (United Kingdom); Chudaykin, A.; Gorbunov, D., E-mail: Fedor.Bezrukov@manchester.ac.uk, E-mail: chudy@ms2.inr.ac.ru, E-mail: gorby@ms2.inr.ac.ru [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

    2017-06-01

    We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such as Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.

  20. Beyond the New Standard Model in neutrino oscillations

    Indian Academy of Sciences (India)

    [4(RSM)ik αβ sin 2∆SM ik + 2(ISM)ik αβ cos 2∆SM ik ]δ∆NP ik . (34). In eqs (32) and (33) tensors δR and δI are respectively real and imaginary parts of the full tensor Ti,k αβ linear in δWc or δWε. In the case of the non-unitary neutrino mixing the probability is not conserved and for any initial neutrino state α: ∑ all β. Pα→β = 1 ...

  1. Activity report of the Neutrino Research Group. Year 2006

    International Nuclear Information System (INIS)

    2007-01-01

    For the last two decades, neutrino physics has been producing major discoveries including neutrino oscillations. These results gave clear confirmation that active neutrinos oscillate and therefore have mass with three different mass states. This is a very important result showing that the Minimal Standard Model is incomplete and requires an extension which is not yet known. The neutrino research field is very broad and active, at the frontier of today's particle physics. The Neutrino Research Group (GDR) was created in January 2005 with the aim of gathering CEA and CNRS research teams working on Neutrino Physics on experimental or theoretical level. This document is the 2006 activity report of the research group, two years after its creation. It presents the results of the 5 working groups: 1 - Determination of neutrino parameters; 2 - Physics beyond the standard model; 3 - Neutrinos in the universe; 4 - Accelerators, detection means, R and D and valorisation; 5 - Common tools to all working groups. The proposed neutrino physics road-map and the actual and future short-, medium- and long-term projects are presented in appendixes. The Neutrino research group organization, the Memphys specific mission group, the research group participating laboratories and teams, as well as the Memphys project are presented too

  2. A second generation experiment for direct neutrino mass measurement via 187Re β-decay

    Science.gov (United States)

    Gatti, G.; Gallinaro, G.; Pergolesi, D.; Gastaldo, L.; Dussoni, S.; Valle, R.

    2005-06-01

    The calorimetric determination of the neutrino mass by means of cryogenic detector could play a significant role, being in principle able to investigate all the 10 -1eV/ c2 region. However, the question is still open whether the development in this new technique will allow to confirm the expected performancies. A step forward in the advancement of this technology is represented by the incoming second generation experiment on the beta decay of 187Re with superconducting Rhenium microcalorimeters. After the first pioneering experiment done in 1999 [M.Galeazzi et al., Phys. Rev. C 63 (2001) 14302, F.Gatti, et al, Nature, Vol.397, 1999, F.Gatti, Nucl. Phys. B 91 (2001) 293, M.Galeazzi et al., Phys. Rev. Lett. 86 (2001) 1978], we have undertaken an R&D phase for developing detectors with an energy resolution of about 5 eV, about 20 times better than that attained in the previous experiment. Here we describe the main features of the new experiment that is under construction, in which about 300 detectors will be under measurement for 1 year in order to reach an expected sensitivity of the eV/ c2.

  3. Report of the Solar and Atmospheric Neutrino Working Group

    International Nuclear Information System (INIS)

    Back, H.; Bahcall, J.N.; Bernabeu, J.; Boulay, M.G.; Bowles, T.; Calaprice, F.; Champagne, A.; Freedman, S.; Gai, M.; Galbiati, C.; Gallagher, H.; Gonzalez-Garcia, C.; Hahn, R.L.; Heeger, K.M.; Hime, A.; Jung, C.K.; Klein, J.R.; Koike, M.; Lanou, R.; Learned, J.G.; Lesko, K.T.; Losecco, J.; Maltoni, M.; Mann, A.; McKinsey, D.; Palomares-Ruiz, S.; Pena-Garay, C.; Petcov, S.T.; Piepke, A.; Pitt, M.; Raghavan, R.; Robertson, R.G.H.; Scholberg, K.; Sobel, H.W.; Takeuchi, T.; Vogelaar, R.; Wolfenstein, L.

    2004-01-01

    The highest priority of the Solar and Atmospheric Neutrino Experiment Working Group is the development of a real-time, precision experiment that measures the pp solar neutrino flux. A measurement of the pp solar neutrino flux, in comparison with the existing precision measurements of the high energy 8 B neutrino flux, will demonstrate the transition between vacuum and matter-dominated oscillations, thereby quantitatively testing a fundamental prediction of the standard scenario of neutrino flavor transformation. The initial solar neutrino beam is pure ν e , which also permits sensitive tests for sterile neutrinos. The pp experiment will also permit a significantly improved determination of θ 12 and, together with other solar neutrino measurements, either a measurement of θ 13 or a constraint a factor of two lower than existing bounds. In combination with the essential pre-requisite experiments that will measure the 7 Be solar neutrino flux with a precision of 5%, a measurement of the pp solar neutrino flux will constitute a sensitive test for non-standard energy generation mechanisms within the Sun. The Standard Solar Model predicts that the pp and 7 Be neutrinos together constitute more than 98% of the solar neutrino flux. The comparison of the solar luminosity measured via neutrinos to that measured via photons will test for any unknown energy generation mechanisms within the nearest star. A precise measurement of the pp neutrino flux (predicted to be 92% of the total flux) will also test stringently the theory of stellar evolution since the Standard Solar Model predicts the pp flux with a theoretical uncertainty of 1%. We also find that an atmospheric neutrino experiment capable of resolving the mass hierarchy is a high priority. Atmospheric neutrino experiments may be the only alternative to very long baseline accelerator experiments as a way of resolving this fundamental question. Such an experiment could be a very large scale water Cerenkov detector, or a

  4. Report of the Solar and Atmospheric Neutrino Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Back, H.; Bahcall, J.N.; Bernabeu, J.; Boulay, M.G.; Bowles, T.; Calaprice, F.; Champagne, A.; Freedman, S.; Gai, M.; Galbiati, C.; Gallagher, H.; Gonzalez-Garcia, C.; Hahn, R.L.; Heeger, K.M.; Hime, A.; Jung, C.K.; Klein, J.R.; Koike, M.; Lanou, R.; Learned, J.G.; Lesko, K.T.; Losecco, J.; Maltoni, M.; Mann, A.; McKinsey, D.; Palomares-Ruiz, S.; Pena-Garay, C.; Petcov, S.T.; Piepke, A.; Pitt, M.; Raghavan, R.; Robertson, R.G.H.; Scholberg, K.; Sobel, H.W.; Takeuchi, T.; Vogelaar, R.; Wolfenstein, L.

    2004-10-22

    The highest priority of the Solar and Atmospheric Neutrino Experiment Working Group is the development of a real-time, precision experiment that measures the pp solar neutrino flux. A measurement of the pp solar neutrino flux, in comparison with the existing precision measurements of the high energy {sup 8}B neutrino flux, will demonstrate the transition between vacuum and matter-dominated oscillations, thereby quantitatively testing a fundamental prediction of the standard scenario of neutrino flavor transformation. The initial solar neutrino beam is pure {nu}{sub e}, which also permits sensitive tests for sterile neutrinos. The pp experiment will also permit a significantly improved determination of {theta}{sub 12} and, together with other solar neutrino measurements, either a measurement of {theta}{sub 13} or a constraint a factor of two lower than existing bounds. In combination with the essential pre-requisite experiments that will measure the {sup 7}Be solar neutrino flux with a precision of 5%, a measurement of the pp solar neutrino flux will constitute a sensitive test for non-standard energy generation mechanisms within the Sun. The Standard Solar Model predicts that the pp and {sup 7}Be neutrinos together constitute more than 98% of the solar neutrino flux. The comparison of the solar luminosity measured via neutrinos to that measured via photons will test for any unknown energy generation mechanisms within the nearest star. A precise measurement of the pp neutrino flux (predicted to be 92% of the total flux) will also test stringently the theory of stellar evolution since the Standard Solar Model predicts the pp flux with a theoretical uncertainty of 1%. We also find that an atmospheric neutrino experiment capable of resolving the mass hierarchy is a high priority. Atmospheric neutrino experiments may be the only alternative to very long baseline accelerator experiments as a way of resolving this fundamental question. Such an experiment could be a very

  5. Anarchy and neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, Jean-François; Giasson, Nicolas; Marleau, Luc [Département de Physique, de Génie Physique et d’Optique,Université Laval, Québec, QC G1V 0A6 (Canada)

    2017-04-21

    The neutrino sector of a seesaw-extended Standard Model is investigated under the anarchy hypothesis. The previously derived probability density functions for neutrino masses and mixings, which characterize the type I-III seesaw ensemble of N×N complex random matrices, are used to extract information on the relevant physical parameters. For N=2 and N=3, the distributions of the light neutrino masses, as well as the mixing angles and phases, are obtained using numerical integration methods. A systematic comparison with the much simpler type II seesaw ensemble is also performed to point out the fundamental differences between the two ensembles. It is found that the type I-III seesaw ensemble is better suited to accommodate experimental data. Moreover, the results indicate a strong preference for the mass splitting associated to normal hierarchy. However, since all permutations of the singular values are found to be equally probable for a particular mass splitting, predictions regarding the hierarchy of the mass spectrum remains out of reach in the framework of anarchy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R. J.

    2015-06-01

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

  7. Dark energy from pNGB mediated Dirac neutrino condensate

    Directory of Open Access Journals (Sweden)

    Ujjal Kumar Dey

    2018-03-01

    Full Text Available We consider an extension of the Standard Model that provide an unified description of eV scale neutrino mass and dark energy. An explicit model is presented by augmenting the Standard Model with an SU(2L doublet scalar, a singlet scalar and right handed neutrinos where all of them are assumed to be charged under a global U(1X symmetry. A light pseudo-Nambu–Goldstone Boson, associated with the spontaneously broken U(1X symmetry, acts as a mediator of an attractive force leading to a Dirac neutrino condensate, with large correlation length, and a non-zero gap in the right range providing a cosmologically feasible dark energy scenario. The neutrino mass is generated through the usual Dirac seesaw mechanism. Parameter space, reproducing viable dark energy scenario while having neutrino mass in the right ballpark, is presented.

  8. Dark energy from pNGB mediated Dirac neutrino condensate

    Science.gov (United States)

    Dey, Ujjal Kumar; Ray, Tirtha Sankar; Sarkar, Utpal

    2018-03-01

    We consider an extension of the Standard Model that provide an unified description of eV scale neutrino mass and dark energy. An explicit model is presented by augmenting the Standard Model with an SU(2)L doublet scalar, a singlet scalar and right handed neutrinos where all of them are assumed to be charged under a global U(1)X symmetry. A light pseudo-Nambu-Goldstone Boson, associated with the spontaneously broken U(1)X symmetry, acts as a mediator of an attractive force leading to a Dirac neutrino condensate, with large correlation length, and a non-zero gap in the right range providing a cosmologically feasible dark energy scenario. The neutrino mass is generated through the usual Dirac seesaw mechanism. Parameter space, reproducing viable dark energy scenario while having neutrino mass in the right ballpark, is presented.

  9. Search for heavy neutrinos and W$_R$ bosons with right-handed couplings in a left-right symmetric model in pp collisions at 7 TeV

    CERN Document Server

    Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Melo Da Costa, Eliza; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Malek, Magdalena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Vilela Pereira, Antonio; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; 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; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard

    2012-01-01

    Results are presented from a search for heavy, right-handed muon neutrinos, M[mu], and right-handed W[R] bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 inverse femtobarn sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the W[R] mass, dependent on the value of M(W[R]). The excluded region in the two-dimensional (M(W[R]), M(N[mu])) mass plane extends to M(W[R]) = 2.5 TeV.

  10. Sites That Can Produce Left-Handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model

    OpenAIRE

    Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka

    2018-01-01

    The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids having partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.

  11. Sites that Can Produce Left-handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model

    Science.gov (United States)

    Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka

    2018-03-01

    The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids with partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.

  12. Sphaleron-induced baryon-number nonconservation and a constraint on Majorana neutrino masses

    International Nuclear Information System (INIS)

    Fukugita, M.; Yanagida, T.

    1990-01-01

    We point out that the baryon-number asymmetry in the Universe is erased by the sphaleron effect just below the electroweak phase transition irrespective of the primordial baryon- and lepton-number asymmetry, if there exists a Majorana-type interaction. The requirement to avoid this happening leads to the condition that m ν (Majorana) <50 keV for all species of neutrinos, regardless of whether or not neutrinos are stable

  13. Calculation of atmospheric neutrino flux using the interaction model calibrated with atmospheric muon data

    International Nuclear Information System (INIS)

    Honda, M.; Kajita, T.; Kasahara, K.; Midorikawa, S.; Sanuki, T.

    2007-01-01

    Using the 'modified DPMJET-III' model explained in the previous paper [T. Sanuki et al., preceding Article, Phys. Rev. D 75, 043005 (2007).], we calculate the atmospheric neutrino flux. The calculation scheme is almost the same as HKKM04 [M. Honda, T. Kajita, K. Kasahara, and S. Midorikawa, Phys. Rev. D 70, 043008 (2004).], but the usage of the 'virtual detector' is improved to reduce the error due to it. Then we study the uncertainty of the calculated atmospheric neutrino flux summarizing the uncertainties of individual components of the simulation. The uncertainty of K-production in the interaction model is estimated using other interaction models: FLUKA'97 and FRITIOF 7.02, and modifying them so that they also reproduce the atmospheric muon flux data correctly. The uncertainties of the flux ratio and zenith angle dependence of the atmospheric neutrino flux are also studied

  14. Large tau and tau neutrino electric dipole moments in models with vectorlike multiplets

    International Nuclear Information System (INIS)

    Ibrahim, Tarek; Nath, Pran

    2010-01-01

    It is shown that the electric dipole moment of the τ lepton several orders of magnitude larger than predicted by the standard model can be generated from mixings in models with vectorlike mutiplets. The electric dipole moment (EDM) of the τ lepton arises from loops involving the exchange of the W, the charginos, the neutralinos, the sleptons, the mirror leptons, and the mirror sleptons. The EDM of the Dirac τ neutrino is also computed from loops involving the exchange of the W, the charginos, the mirror leptons, and the mirror sleptons. A numerical analysis is presented, and it is shown that the EDMs of the τ lepton and the τ neutrino which lie just a couple of orders of magnitude below the sensitivity of the current experiment can be achieved. Thus the predictions of the model are testable in an improved experiment on the EDM of the τ and the τ neutrino.

  15. Future Long-Baseline Neutrino Facilities and Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Diwan, Milind [Brookhaven; Edgecock, Rob [Huddersfield U.; Hasegawa, Takuya [KEK, Tsukuba; Patzak, Thomas [APC, Paris; Shiozawa, Masato [Kamioka Observ.; Strait, Jim [Fermilab

    2013-01-01

    We review the ongoing effort in the US, Japan, and Europe of the scientific community to study the location and the detector performance of the next-generation long-baseline neutrino facility. For many decades, research on the properties of neutrinos and the use of neutrinos to study the fundamental building blocks of matter has unveiled new, unexpected laws of nature. Results of neutrino experiments have triggered a tremendous amount of development in theory: theories beyond the standard model or at least extensions of it and development of the standard solar model and modeling of supernova explosions as well as the development of theories to explain the matter-antimatter asymmetry in the universe. Neutrino physics is one of the most dynamic and exciting fields of research in fundamental particle physics and astrophysics. The next-generation neutrino detector will address two aspects: fundamental properties of the neutrino like mass hierarchy, mixing angles, and the CP phase, and low-energy neutrino astronomy with solar, atmospheric, and supernova neutrinos. Such a new detector naturally allows for major improvements in the search for nucleon decay. A next-generation neutrino observatory needs a huge, megaton scale detector which in turn has to be installed in a new, international underground laboratory, capable of hosting such a huge detector.

  16. Future Long-Baseline Neutrino Facilities and Detectors

    Directory of Open Access Journals (Sweden)

    Milind Diwan

    2013-01-01

    Full Text Available We review the ongoing effort in the US, Japan, and Europe of the scientific community to study the location and the detector performance of the next-generation long-baseline neutrino facility. For many decades, research on the properties of neutrinos and the use of neutrinos to study the fundamental building blocks of matter has unveiled new, unexpected laws of nature. Results of neutrino experiments have triggered a tremendous amount of development in theory: theories beyond the standard model or at least extensions of it and development of the standard solar model and modeling of supernova explosions as well as the development of theories to explain the matter-antimatter asymmetry in the universe. Neutrino physics is one of the most dynamic and exciting fields of research in fundamental particle physics and astrophysics. The next-generation neutrino detector will address two aspects: fundamental properties of the neutrino like mass hierarchy, mixing angles, and the CP phase, and low-energy neutrino astronomy with solar, atmospheric, and supernova neutrinos. Such a new detector naturally allows for major improvements in the search for nucleon decay. A next-generation neutrino observatory needs a huge, megaton scale detector which in turn has to be installed in a new, international underground laboratory, capable of hosting such a huge detector.

  17. Upper limit of the muon-neutrino mass and charged-pion mass from the momentum analysis of a surface muon beam

    International Nuclear Information System (INIS)

    Kettle, P.R.

    1996-01-01

    Using a surface muon beam and a magnetic spectrometer equipped with a position-sensitive detector, we have measured the muon momentum from pion decay at rest π + →μ + ν μ , to be p μ + =(29.79200±0.00011)MeV/c. This value together with the muon mass and the favoured pion mass leads to an upper limit of 0.17 MeV (90%CL) for the muon-neutrino mass. (author) 4 figs., 5 refs

  18. Upper limit of the muon-neutrino mass and charged-pion mass from the momentum analysis of a surface muon beam

    Energy Technology Data Exchange (ETDEWEB)

    Kettle, P.R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    Using a surface muon beam and a magnetic spectrometer equipped with a position-sensitive detector, we have measured the muon momentum from pion decay at rest {pi}{sup +}{yields}{mu}{sup +}{nu}{sub {mu}}, to be p{sub {mu}{sup +}}=(29.79200{+-}0.00011)MeV/c. This value together with the muon mass and the favoured pion mass leads to an upper limit of 0.17 MeV (90%CL) for the muon-neutrino mass. (author) 4 figs., 5 refs.

  19. Atmospheric Neutrinos

    Directory of Open Access Journals (Sweden)

    Takaaki Kajita

    2012-01-01

    Full Text Available Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

  20. Influence of hadronic interaction models on characteristics of the high-energy atmospheric neutrino flux

    Science.gov (United States)

    Morozova, A. D.; Kochanov, A. A.; Sinegovskaya, T. S.; Sinegovsky, S. I.

    2017-12-01

    The high-energy conventional atmospheric neutrino fluxes are calculated with the hadronic interaction models: Kimel & Mokhov, QGSJET II-03(04), SIBYL 2.1(2.3), EPOS LHC. The influence of hadron-nuclear interactions on the neutrino flux ratios, v/\\bar{v},({v}μ +{\\bar{v}}μ )/({v}e+{\\bar{v}}e), is studied. A comparison of calculations obtained with use of two different approaches, {\\mathscr{Z}}(E,h) -functions method and the Matrix Cascade Equations (MCEQ), demonstrates close agreement in whole but some of partial contrubutions. The comparison of calculated muon neutrino spectra with the latest experimental data justifies reliability of performed computation which describes correctly the atmospheric neutrino production. The calculation made with the model EPOS LHC, combined with Hillas & Gaisser parametrization of the cosmic ray spectrum, is in close agreement with the best fit of IceCube for energy spetrum of atmospheric muon neutrinos in the energy range 1–500 TeV.

  1. Neutrino Mass and an anomaly in the tritium beta-spectrum. Possible signs of a dense neutrino cloud in the Solar System

    CERN Document Server

    Lobashev, V M

    1998-01-01

    Studying the shape of the tritium spectrum near the end point provides information about the properties of low energy neutrinos including their rest mass. The facility constructed at the Institute for Nuclear Research of the Russian Academy of Sciences, operating in Troitsk since 1994, consists of an electrostatic integral spectrometer with adiabatic magnetic collimation, matched to a window less gaseous tritium source. This apparatus, named the "Troitsk nu-mass" has measured the tritium beta-spectrum to within a few eV of the end point. This gave the lowest upper limit on the electron antineutrino mass mn < 2.5 eV/c2, but revealed a strange narrow bump 5-15 eV below the end-point with branching ratio of about 10-10 of the total decay rate. Latest measurements reveal that the position of the bump varies periodically within 5-15 eV of the end-point with a period 0.504±0.003 year. Such periodicity gives rise to the speculation that this phenomenon might originate from some object within the Solar System, wh...

  2. Neutrino physics with SHIP

    CERN Document Server

    van Herwijnen, Eric

    2016-01-01

    SHIP is a new general purpose fixed target facility, whose Technical Proposal has been recently reviewed by the CERN SPS Committee. It recommended that the experiment proceed further to a Comprehensive Design phase. In its initial phase, the 400 GeV proton beam extracted from the SPS will be dumped on a heavy target with the aim of integrating 2×1020 POT (Protons On Target) in 5 years. A dedicated detector, based on a long vacuum tank followed by a spectrometer and particle identification detectors, will allow probing a variety of models with light long-lived exotic particles and masses below O(10) GeV/c 2 . The main focus will be the physics of the so-called Hidden Portals. The sensitivity to Heavy Neutrinos will allow to probe for the first time the mass range between the kaon and the charm meson mass, and a range of couplings for which Baryogenesis and active neutrino masses could also be explained. Another dedicated detector will allow the study of neutrino cross-sections and angular distributions. ντ ...

  3. Detection of supernova neutrinos with neutrino-iron scattering

    International Nuclear Information System (INIS)

    Samana, A. R.; Bertulani, C. A.

    2008-01-01

    The ν e - 56 Fe cross section is evaluated in the projected quasiparticle random phase approximation (PQRPA). This model solves the puzzle observed in RPA for nuclei with mass around 12 C, because it is the only RPA model that treats the Pauli Principle correctly. The cross sections as a function of the incident neutrino energy are compared with recent theoretical calculations of similar models. The average cross section weighted with the flux spectrum yields a good agreement with the experimental data. The expected number of events in the detection of supernova neutrinos is calculated for the LVD detector, leading to an upper limit for the electron neutrino energy of particular importance in this experiment

  4. Cosmological parameter analysis including SDSS Lyα forest and galaxy bias: Constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy

    International Nuclear Information System (INIS)

    Seljak, Uros; Makarov, Alexey; McDonald, Patrick; Anderson, Scott F.; Bahcall, Neta A.; Cen, Renyue; Gunn, James E.; Lupton, Robert H.; Schlegel, David J.; Brinkmann, J.; Burles, Scott; Doi, Mamoru; Ivezic, Zeljko; Kent, Stephen; Loveday, Jon; Munn, Jeffrey A.; Nichol, Robert C.; Ostriker, Jeremiah P.; Schneider, Donald P.; Berk, Daniel E. Vanden

    2005-01-01

    We combine the constraints from the recent Lyα forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from SDSS galaxy clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies. We find significant improvements on all of the cosmological parameters compared to previous constraints, which highlights the importance of combining Lyα forest constraints with other probes. Combining WMAP and the Lyα forest we find for the primordial slope n s =0.98±0.02. We see no evidence of running, dn/dlnk=-0.003±0.010, a factor of 3 improvement over previous constraints. We also find no evidence of tensors, r 2 model is within the 2-sigma contour, V∝φ 4 is outside the 3-sigma contour. For the amplitude we find σ 8 =0.90±0.03 from the Lyα forest and WMAP alone. We find no evidence of neutrino mass: for the case of 3 massive neutrino families with an inflationary prior, eV and the mass of lightest neutrino is m 1 ν λ =0.72±0.02, w(z=0.3)=-0.98 -0.12 +0.10 , the latter changing to w(z=0.3)=-0.92 -0.10 +0.09 if tensors are allowed. We find no evidence for variation of the equation of state with redshift, w(z=1)=-1.03 -0.28 +0.21 . These results rely on the current understanding of the Lyα forest and other probes, which need to be explored further both observationally and theoretically, but extensive tests reveal no evidence of inconsistency among different data sets used here

  5. Neutrino anomaly and -nucleus interactions

    Indian Academy of Sciences (India)

    The neutrino anomaly generally refers to the solar neutrino problem where the observed number of electron type neutrinos from the sun was found to be considerably smaller than the number predicted in standard model of particle interactions [1–2]. Similar depletion of muon type neutrinos is found in the flux of atmospheric ...

  6. Search for $\\beta$-transitions with the lowest decay energy for a determination of the neutrino mass

    CERN Multimedia

    From a variety of $\\beta$-transitions only those with decay energies of a few keV and smaller are considered suitable for a determination of the neutrino mass on a sub-eV level. The decay energy of a transition can be very small, if, e.g., in an allowed $\\beta$-decay or electron-capture transition, a nuclear excited state of the daughter nuclide is populated whose energy is very close to the mass difference of the transition nuclides. Investigation of these transitions can also be useful for the assessment of a validity of the current $\\beta$-decay theory in the region of vanishingly small decay energies. The authors of this proposal have found several such $\\beta$-transitions whose decay energies are expected to be extremely small. In order to assess the suitability of these $\\beta$-transitions for the determination of the neutrino mass, measurements of the mass differences of the transition nuclides must be carried out with a sub-keV uncertainty. Presently, only high-precision Penning-trap mass spectrometry...

  7. Neutrino-nucleon cross-section at ultra-high energies in models with ...

    Indian Academy of Sciences (India)

    sUKANTA PANDA. Physics Department, Indian Institute of Technology, Kanpur 208 016, India. Abstract. We examine whether the models with large extra dimensions can provide an explanation for the GZK violating ultra-high energy cosmic rays (UHECR). In these models the neutrino-nucleon cross-section rises rapidly ...

  8. Neutrino Pair Cerenkov Radiation for Tachyonic Neutrinos

    Directory of Open Access Journals (Sweden)

    Ulrich D. Jentschura

    2017-01-01

    Full Text Available The emission of a charged light lepton pair by a superluminal neutrino has been identified as a major factor in the energy loss of highly energetic neutrinos. The observation of PeV neutrinos by IceCube implies their stability against lepton pair Cerenkov radiation. Under the assumption of a Lorentz-violating dispersion relation for highly energetic superluminal neutrinos, one may thus constrain the Lorentz-violating parameters. A kinematically different situation arises when one assumes a Lorentz-covariant, space-like dispersion relation for hypothetical tachyonic neutrinos, as an alternative to Lorentz-violating theories. We here discuss a hitherto neglected decay process, where a highly energetic tachyonic neutrino may emit other (space-like, tachyonic neutrino pairs. We find that the space-like dispersion relation implies the absence of a q2 threshold for the production of a tachyonic neutrino-antineutrino pair, thus leading to the dominant additional energy loss mechanism for an oncoming tachyonic neutrino in the medium-energy domain. Surprisingly, the small absolute values of the decay rate and energy loss rate in the tachyonic model imply that these models, in contrast to the Lorentz-violating theories, are not pressured by the cosmic PeV neutrinos registered by the IceCube collaboration.

  9. A4 see-saw models and form dominance

    International Nuclear Information System (INIS)

    Chen, M-C; King, Stephen F.

    2009-01-01

    We introduce the idea of Form Dominance in the (type I) see-saw mechanism, according to which a particular right-handed neutrino mass eigenstate is associated with a particular physical neutrino mass eigenstate, leading to a form diagonalizable effective neutrino mass matrix. Form Dominance, which allows an arbitrary neutrino mass spectrum, may be regarded as a generalization of Constrained Sequential Dominance which only allows strongly hierarchical neutrino masses. We consider alternative implementations of the see-saw mechanism in minimal A 4 see-saw models and show that such models satisfy Form Dominance, leading to neutrino mass sum rules which predict closely spaced neutrino masses with a normal or inverted neutrino mass ordering. To avoid the partial cancellations inherent in such models we propose Natural Form Dominance, in which a different flavon is associated with each physical neutrino mass eigenstate.

  10. Beam and experiments summary [neutrino studies

    CERN Document Server

    Blondel, A; Campanelli, M; Cervera-Villanueva, Anselmo; Cline, David B; Collot, J; De Jong, M; Donini, Andrea; Dydak, Friedrich; Edgecock, R; Gavela-Legazpi, Maria Belen; Gómez-Cadenas, J J; González-Garciá, M Concepción; Gruber, P; Harris, D A; Hernández, Pilar; Kuno, Y; Litchfield, P J; McFarland, K; Mena, O; Migliozzi, P; Palladino, Vittorio; Panman, J; Papadopoulos, I M; Para, A; Peña-Garay, C; Pérez, P; Rigolin, Stefano; Romanino, Andrea; Rubbia, André; Strolin, P; Wojcicki, S G

    2000-01-01

    The discovery of neutrino oscillations marks a major milestone in the history of neutrino physics, and opens a new window to the still mysterious origin of masses and flavour mixing. Many current and forthcoming experiments will. Answer open questions; however, a major step forward, up to and possibly including CP violation in the neutrino-mixing matrix, requires the neutrino beams from a neutrino factory. The neutrino factory is a new concept for producing neutrino beams of unprecedented quality in terms of intensity, flavour composition, and precision of the beam parameters. Most importantly, the neutrino factory is the only known way to generate a high- intensity beam of electron neutrinos of high energy. The neutrino beam from a neutrino factory, in particular the electron-neutrino beam, enables the exploration of otherwise inaccessible domains in neutrino oscillation physics by exploiting baselines of planetary dimensions. Suitable detectors pose formidable challenges but seem within reach with only mode...

  11. Dark matter relic abundance and light sterile neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yi-Lei [Center for High Energy Physics,Peking University, Beijing 100871 (China); Zhu, Shou-hua [Center for High Energy Physics,Peking University, Beijing 100871 (China); Institute of Theoretical Physics & State Key Laboratory of Nuclear Physics and Technology,Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter,Beijing 100871 (China)

    2017-01-09

    In this paper, we calculate the relic abundance of the dark matter particles when they can annihilate into sterile neutrinos with the mass ≲100 GeV in a simple model. Unlike the usual standard calculations, the sterile neutrino may fall out of the thermal equilibrium with the thermal bath before the dark matter freezes out. In such a case, if the Yukawa coupling y{sub N} between the Higgs and the sterile neutrino is small, this process gives rise to a larger Ω{sub DM}h{sup 2} so we need a larger coupling between the dark matter and the sterile neutrino for a correct relic abundance.

  12. Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

    International Nuclear Information System (INIS)

    Anokhina, A.; Dzhatdoev, T.; Morgunova, O.; Roganova, T.; Bagulya, A.; Chernyavskiy, M.; Dalkarov, O.; Mingazheva, R.; Shchedrina, T.; Starkov, N.; Vladymyrov, M.; Benettoni, M.; Dal Corso, F.; Dusini, S.; Lippi, I.; Longhin, A.; Bernardini, P.; Mancarella, G.; Marsella, G.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Roda, M.; Sirignano, C.; Calabrese, M.; Fiore, G.; Surdo, A.; Cecchetti, A.; Orecchini, D.; Paoloni, A.; Cecchini, S.; Di Ferdinando, D.; Guerzoni, M.; Laurenti, G.; Mandrioli, G.; Mauri, N.; Patrizii, L.; Pozzato, M.; Sahnoun, Z.; Sirri, G.; Togo, V.; Del Prete, A.; Papadia, G.; De Robertis, G.; Fini, R.A.; Loddo, F.; Pastore, A.; De Serio, M.; Paparella, L.; Simone, S.; Klicek, B.; Jakovcic, K.; Malenica, M.; Stipcevic, M.; Kose, U.; Nessi, M.; Margiotta, A.; Pasqualini, L.; Spurio, M.; Muciaccia, M.T.; Polukhina, N.; Rosa, G.; Stanco, L.; Tenti, M.

    2017-01-01

    The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν μ disappearance and the ν e appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν μ disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far. (orig.)

  13. Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

    Science.gov (United States)

    Anokhina, A.; Bagulya, A.; Benettoni, M.; Bernardini, P.; Brugnera, R.; Calabrese, M.; Cecchetti, A.; Cecchini, S.; Chernyavskiy, M.; Dal Corso, F.; Dalkarov, O.; Del Prete, A.; De Robertis, G.; De Serio, M.; Di Ferdinando, D.; Dusini, S.; Dzhatdoev, T.; Fini, R. A.; Fiore, G.; Garfagnini, A.; Guerzoni, M.; Klicek, B.; Kose, U.; Jakovcic, K.; Laurenti, G.; Lippi, I.; Loddo, F.; Longhin, A.; Malenica, M.; Mancarella, G.; Mandrioli, G.; Margiotta, A.; Marsella, G.; Mauri, N.; Medinaceli, E.; Mingazheva, R.; Morgunova, O.; Muciaccia, M. T.; Nessi, M.; Orecchini, D.; Paoloni, A.; Papadia, G.; Paparella, L.; Pasqualini, L.; Pastore, A.; Patrizii, L.; Polukhina, N.; Pozzato, M.; Roda, M.; Roganova, T.; Rosa, G.; Sahnoun, Z.; Shchedrina, T.; Simone, S.; Sirignano, C.; Sirri, G.; Spurio, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Surdo, A.; Tenti, M.; Togo, V.; Vladymyrov, M.

    2017-01-01

    The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν _{μ } disappearance and the ν e appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν _{μ } disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far.

  14. Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Anokhina, A.; Dzhatdoev, T.; Morgunova, O.; Roganova, T. [Lomonosov Moscow State University (MSU SINP), Moscow (Russian Federation); Bagulya, A.; Chernyavskiy, M.; Dalkarov, O.; Mingazheva, R.; Shchedrina, T.; Starkov, N.; Vladymyrov, M. [Lebedev Physical Institute of Russian Academy of Sciences, Moscow (Russian Federation); Benettoni, M.; Dal Corso, F.; Dusini, S.; Lippi, I.; Longhin, A. [INFN, Sezione di Padova, Padua (Italy); Bernardini, P.; Mancarella, G.; Marsella, G. [Universita del Salento, Dipartimento di Matematica e Fisica, Lecce (Italy); INFN, Sezione di Lecce, Lecce (Italy); Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Roda, M.; Sirignano, C. [INFN, Sezione di Padova, Padua (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); Calabrese, M.; Fiore, G.; Surdo, A. [INFN, Sezione di Lecce, Lecce (Italy); Cecchetti, A.; Orecchini, D.; Paoloni, A. [INFN, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Cecchini, S.; Di Ferdinando, D.; Guerzoni, M.; Laurenti, G.; Mandrioli, G.; Mauri, N.; Patrizii, L.; Pozzato, M.; Sahnoun, Z.; Sirri, G.; Togo, V. [INFN, Sezione di Bologna, Bologna (Italy); Del Prete, A.; Papadia, G. [INFN, Sezione di Lecce, Lecce (Italy); Universita del Salento, Dipartimento di Ingegneria dell' Innovazione, Lecce (Italy); De Robertis, G.; Fini, R.A.; Loddo, F.; Pastore, A. [INFN, Sezione di Bari, Bari (Italy); De Serio, M.; Paparella, L.; Simone, S. [INFN, Sezione di Bari, Bari (Italy); Universita di Bari, Dipartimento di Fisica, Bari (Italy); Klicek, B.; Jakovcic, K.; Malenica, M.; Stipcevic, M. [Rudjer Boskovic Institute, Zagreb (Croatia); Kose, U.; Nessi, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Margiotta, A.; Pasqualini, L.; Spurio, M. [INFN, Sezione di Bologna, Bologna (Italy); Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); Muciaccia, M.T. [Universita di Bari, Dipartimento di Fisica, Bari (Italy); Polukhina, N. [Lebedev Physical Institute of Russian Academy of Sciences, Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation); Rosa, G. [INFN, Sezione di Roma, Rome (Italy); Stanco, L. [INFN, Sezione di Padova, Padua (Italy); Tenti, M. [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); NFN-CNAF, Bologna (Italy)

    2017-01-15

    The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν{sub μ} disappearance and the ν{sub e} appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν{sub μ} disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far. (orig.)

  15. Galaxy clustering, CMB and supernova data constraints on ϕCDM model with massive neutrinos

    Directory of Open Access Journals (Sweden)

    Yun Chen

    2016-01-01

    Full Text Available We investigate a scalar field dark energy model (i.e., ϕCDM model with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., V(ϕ∝ϕ−α (α>0. We find that the sum of neutrino masses Σmν has significant impacts on the CMB temperature power spectrum and on the matter power spectrum. In addition, the parameter α also has slight impacts on the spectra. A joint sample, including CMB data from Planck 2013 and WMAP9, galaxy clustering data from WiggleZ and BOSS DR11, and JLA compilation of Type Ia supernova observations, is adopted to confine the parameters. Within the context of the ϕCDM model under consideration, the joint sample determines the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the Thomson scattering optical depth due to reionization, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ⁎=(1.0415−0.0011+0.0012×10−2, τ=0.0914−0.0242+0.0266, Ωbh2=0.0222±0.0005, Ωch2=0.1177±0.0036, and ns=0.9644−0.0119+0.0118, respectively, at 95% confidence level (CL. It turns out that α<4.995 at 95% CL for the ϕCDM model. And yet, the ΛCDM scenario corresponding to α=0 is not ruled out at 95% CL. Moreover, we get Σmν<0.262 eV at 95% CL for the ϕCDM model, while the corresponding one for the ΛCDM model is Σmν<0.293 eV. The allowed scale of Σmν in the ϕCDM model is a bit smaller than that in the ΛCDM model. It is consistent with the qualitative analysis, which reveals that the increases of α and Σmν both can result in the suppression of the matter power spectrum. As a consequence, when α is larger, in order to avoid suppressing the matter power spectrum too much, the value of Σmν should be smaller.

  16. Direct Measurement of the Mass Difference of (163)Ho and (163)Dy Solves the Q-Value Puzzle for the Neutrino Mass Determination.

    Science.gov (United States)

    Eliseev, S; Blaum, K; Block, M; Chenmarev, S; Dorrer, H; Düllmann, Ch E; Enss, C; Filianin, P E; Gastaldo, L; Goncharov, M; Köster, U; Lautenschläger, F; Novikov, Yu N; Rischka, A; Schüssler, R X; Schweikhard, L; Türler, A

    2015-08-07

    The atomic mass difference of (163)Ho and (163)Dy has been directly measured with the Penning-trap mass spectrometer SHIPTRAP applying the novel phase-imaging ion-cyclotron-resonance technique. Our measurement has solved the long-standing problem of large discrepancies in the Q value of the electron capture in (163)Ho determined by different techniques. Our measured mass difference shifts the current Q value of 2555(16) eV evaluated in the Atomic Mass Evaluation 2012 [G. Audi et al., Chin. Phys. C 36, 1157 (2012)] by more than 7σ to 2833(30(stat))(15(sys)) eV/c(2). With the new mass difference it will be possible, e.g., to reach in the first phase of the ECHo experiment a statistical sensitivity to the neutrino mass below 10 eV, which will reduce its present upper limit by more than an order of magnitude.

  17. Sudbury Neutrino Observatory

    International Nuclear Information System (INIS)

    Beier, E.W.

    1992-03-01

    This document is a technical progress report on work performed at the University of Pennsylvania during the current year on the Sudbury Neutrino Observatory project. The motivation for the experiment is the measurement of neutrinos emitted by the sun. The Sudbury Neutrino Observatory (SNO) is a second generation dedicated solar neutrino experiment which will extend the results of our work with the Kamiokande II detector by measuring three reactions of neutrinos rather than the single reaction measured by the Kamiokande experiment. The collaborative project includes physicists from Canada, the United Kingdom, and the United States. Full funding for the construction of this facility was obtained in January 1990, and its construction is estimated to take five years. The motivation for the SNO experiment is to study the fundamental properties of neutrinos, in particular the mass and mixing parameters, which remain undetermined after decades of experiments in neutrino physics utilizing accelerators and reactors as sources of neutrinos. To continue the study of neutrino properties it is necessary to use the sun as a neutrino source. The long distance to the sun makes the search for neutrino mass sensitive to much smaller mass than can be studied with terrestrial sources. Furthermore, the matter density in the sun is sufficiently large to enhance the effects of small mixing between electron neutrinos and mu or tau neutrinos. This experiment, when combined with the results of the radiochemical 37 Cl and 71 Ga experiments and the Kamiokande II experiment, should extend our knowledge of these fundamental particles, and as a byproduct, improve our understanding of energy generation in the sun

  18. Activity report of the Neutrino Research Group. Year 2010

    International Nuclear Information System (INIS)

    2011-01-01

    For the last two decades, neutrino physics has been producing major discoveries including neutrino oscillations. These results gave clear confirmation that active neutrinos oscillate and therefore have mass with three different mass states. This is a very important result showing that the Minimal Standard Model is incomplete and requires an extension which is not yet known. The neutrino research field is very broad and active, at the frontier of today's particle physics. The Neutrino Research Group (GDR) was created in January 2005 with the aim of gathering CEA and CNRS research teams working on Neutrino Physics on experimental or theoretical level. This document is the 2010 activity report of the research group, six years after its creation. It presents the results of the 5 working groups: 1 - Determination of neutrino parameters; 2 - Physics beyond the standard model; 3 - Neutrinos in the universe; 4 - Accelerators, detection means, R and D and valorisation; 5 - Common tools to all working groups. The proposed neutrino physics road-map and the actual and future short-, medium- and long-term projects are presented in appendixes

  19. Research program of the Neutrino Research Group. Year 2004

    International Nuclear Information System (INIS)

    2004-01-01

    For the last two decades, neutrino physics has been producing major discoveries including neutrino oscillations. These results gave clear confirmation that active neutrinos oscillate and therefore have mass with three different mass states. This is a very important result showing that the Minimal Standard Model is incomplete and requires an extension which is not yet known. The neutrino research field is very broad and active, at the frontier of today's particle physics. The creation of a Neutrino Research Group (GDR) was proposed in 2004 with the aim of gathering CEA and CNRS research teams working on Neutrino Physics on experimental or theoretical level. This document presents the Research program of the Neutrino Research Group which is divided into 5 working groups with the following activities: 1 - Determination of neutrino parameters; 2 - Physics beyond the standard model; 3 - Neutrinos in the universe; 4 - Accelerators, detection means, R and D and valorisation; 5 - Common tools to all working groups. The research group participating laboratories and teams are listed at the end of the document

  20. Neutrino Research Group. 2011-2014 activity report

    International Nuclear Information System (INIS)

    2014-01-01

    For the last two decades, neutrino physics has been producing major discoveries including neutrino oscillations. These results gave clear confirmation that active neutrinos oscillate and therefore have mass with three different mass states. This is a very important result showing that the Minimal Standard Model is incomplete and requires an extension which is not yet known. The neutrino research field is very broad and active, at the frontier of today's particle physics. The Neutrino Research Group (GDR) was created in January 2005 with the aim of gathering CEA and CNRS research teams working on Neutrino Physics on experimental or theoretical level. This document is the 2011-2014 activity report of the research group, ten years after its creation. It presents the results of the 5 working groups: 1 - Determination of neutrino parameters; 2 - Physics beyond the standard model; 3 - Neutrinos in the universe; 4 - Accelerators, detection means, R and D and valorisation; 5 - Common tools to all working groups. The research group structure, participating laboratories and teams and the neutrino physics road-map are presented in appendixes