scholarly journals CONFRONTING HEAVY TAU NEUTRINOS WITH NEUTRINO OSCILLATIONS

2001 ◽  
Vol 16 (26) ◽  
pp. 1699-1702 ◽  
Author(s):  
CHUN LIU
Keyword(s):  
Neutrino Mass ◽  
Neutrino Oscillations ◽  
Electron Neutrino ◽  
Supersymmetric Model ◽  
Tau Neutrino ◽  
Tau Neutrinos ◽  
Mass Pattern

If the tau neutrino is as heavy as 10 MeV which may have certain astrophysical implications, the neutrino mass pattern is studied so as to accommodate the new oscillation observations. It predicts that the electron neutrino has Marjorana mass around 0.05 eV. A supersymmetric model is described to realize the above scenario.

scholarly journals Super-Kamiokande neutrino oscillations and the supersymmetric model

2020 ◽  
Vol 9 ◽  
pp. 14
Author(s):  
A. Faessler
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Electron Neutrino ◽  
Tree Level ◽  
Supersymmetric Model ◽  
Neutrino Masses ◽  
Muon Neutrinos

The standard model predicts a ratio of 2 for the number of atmospheric muon to electron neutrinos, while super-Kamiokande and others measure a much smaller value (1.30±0.02 for super-Kamiokande). Super-Kamiokande is also able to measure roughly the direction and the energy of the neutrinos. The zenith-angle dependence for the muon neutrinos suggests that the muon neutrinos oscillate into a third neutrino species, either into the r neutrino or a sterile neutrino. This finding is inves- tigated within the supersymmetric model. The neutrinos mix with the neutralinos, this meaning the wino, the bino and the two higgsinos. The 7 x 7 mass matrix is calculated on the tree level. One finds that the mass matrix has three linearly dependent rows, which means that two masses are zero. They are identified with the two lightest neutrino masses. The fit of the super-Kamiokande data to oscillations between three neutrinos yields, together with the result of supersymmetry, that the third neutrino mass lies between 2x10^-2 and 10^-1 eV. The two lightest neutrino masses are in supersymmetry on the tree level zero. The averaged electron neutrino mass which is the essential parameter in the neutrinoless double-beta decay is given by {m_ve) ~ m_v3 P_ze < 0.8 x10^-2 eV (95% confidence limit). It is derived from the super-Kamiokande data in this supersymmetric model to be two orders smaller than the best value (1 eV) from the neutrinoless double-beta decay.

scholarly journals ATMOSPHERIC AND GALACTIC TAU NEUTRINOS

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1171-1178 ◽  
Author(s):  
H. ATHAR
Keyword(s):  
Lower Energy ◽  
Neutrino Oscillations ◽  
Galactic Plane ◽  
Neutrino Flux ◽  
Earth Atmosphere ◽  
Future Prospects ◽  
Energy Value ◽  
Tau Neutrino ◽  
Tau Neutrinos ◽  
The Earth

Neutrinos with energy greater than GeV are copiously produced in the p(A,p) interactions occurring in the earth atmosphere and in our galactic plane. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these two astrophysical sites is presented. It is pointed out that the galactic plane tau neutrino flux dominates over the downward going atmospheric tau neutrino flux at much lower energy value than that for the dominance of the mu neutrino flux from these two sites. Future prospects for possible observations of galactic tau neutrino flux are also briefly mentioned.

OSCILLATION EFFECTS ON NEUTRINOS FROM THE EARLY PHASE OF A NEARBY SUPERNOVA

2000 ◽  
Vol 15 (14) ◽  
pp. 2105-2120
Author(s):  
DEBASISH MAJUMDAR ◽  
AMITAVA RAYCHAUDHURI ◽  
KAMALES KAR ◽  
ALAK RAY ◽  
FIROZA K. SUTARIA
Keyword(s):  
Neutrino Mass ◽  
Neutrino Oscillations ◽  
Neutral Current ◽  
Mass Difference ◽  
Solar Neutrinos ◽  
Electron Neutrino ◽  
Charged Current ◽  
Current Channel ◽  
Flavor Oscillation ◽  
Collapse Phase

Recent observations of atmospheric and solar neutrinos strongly support the phenomenon of neutrino oscillations — a manifestation of a nonzero and nondegenerate mass spectrum. Neutrinos emitted during stellar core collapse leading to a supernova are of the electron neutrino type at source — as for solar and reactor (anti-)neutrinos — and provide another useful tool in the search for flavor oscillations. Their propagation to an earth-bound detector involves length scales that can uniquely probe very small neutrino mass differences hitherto unobservable. Although the number of neutrinos emitted during the collapse phase is much smaller than that emitted in the post-bounce epoch (in which all flavors of neutrinos are emitted), a nearby supernova event may nevertheless register a substantial number of detections from the collapse phase at SuperKamiokande (SK) and the Sudbury Neutrino Observatory (SNO). The measurement of the fluence of these neutrinos at SNO and the distortion of the spectrum detected at SK can yield valuable information about neutrino mass difference and mixing which are illustrated here in terms of two- and three-flavor oscillation models. In particular, we find that R SNO , the ratio of the calorimetric detection of the neutrino fluence via the neutral current channel to the total energy integrated fluence observed via the charged current channel at SNO, is a sensitive probe for oscillations. We also find that αn, the ratio of the nth central moments of the distributions seen at SK and SNO (charged current), can be a useful tool (especially for n=3) to look for neutrino oscillations.

scholarly journals NEUTRINO OSCILLATIONS AND THE EXACT PARITY MODEL

1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT
Keyword(s):  
Neutrino Mass ◽  
General Result ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Solar Neutrinos ◽  
Specific Model ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Significant Deficit

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.

scholarly journals Experiments on lepton and baryon stability and oscillation phenomena

1982 ◽  
Vol 304 (1482) ◽  
pp. 105-134 ◽  
Keyword(s):  
Neutrino Mass ◽  
Neutrino Oscillations ◽  
Nuclear Reactors ◽  
Solar And Atmospheric Neutrinos ◽  
High Energy ◽  
Lepton Number ◽  
Atmospheric Neutrinos ◽  
Nucleon Decay ◽  
Number Conservation ◽  
Experimental Approaches

The various experiments on lepton number conservation and on nucleon stability currently being done or prepared are reviewed, and their relative merits compared and discussed. The first part of the paper is devoted to the measurement of the neutrino mass and to the present limits on the conservation of the total lepton number and of the various lepton flavours. The existing results and future projects on the strictly connected problems of neutrino oscillations at nuclear reactors, pion factories and high energy accelerators will be also discussed, together with oscillations of solar and atmospheric neutrinos. The second part of the paper concerns the few results and the m any planned detectors on nucleon decay with particular emphasis on the problems of background radioactivity and of the variety of experimental approaches. Oscillation experiments on neutron—antineutron oscillations at nuclear reactors are also considered.

scholarly journals Perturbation to TBM mixing and its phenomenological implications

2016 ◽  
Vol 31 (38) ◽  
pp. 1650207 ◽  
Author(s):  
M. Sruthilaya ◽  
Srinu Gollu
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Electron Neutrino ◽  
Leading Order ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Upper Limit ◽  
Mixing Matrix ◽  
Reactor Mixing

To accommodate the recently observed nonzero reactor mixing angle [Formula: see text], we consider the lepton mixing matrix as tri-bimaximal mixing (TBM) form in the leading order along with a perturbation in neutrino sector. The perturbation is taken to be a rotation in 23 plane followed by a rotation in 13 plane, i.e. [Formula: see text]. We obtain the allowed values of the parameters [Formula: see text], [Formula: see text] and [Formula: see text], which can accommodate all the observed mixing angles consistently and calculate the phenomenological observables such as the Dirac CP violating phase [Formula: see text], Jarlskog invariant [Formula: see text], effective Majorana mass [Formula: see text] and [Formula: see text], the electron neutrino mass. We find that [Formula: see text] can take any values between [Formula: see text] and [Formula: see text] and [Formula: see text] always comes below its experimental upper limit.

Neutrino Oscillations and Neutrino Mass

2015 ◽  
pp. 167-184 ◽  
Author(s):  
Bogdan Povh ◽  
Klaus Rith ◽  
Christoph Scholz ◽  
Frank Zetsche ◽  
Werner Rodejohann
Keyword(s):  
Neutrino Mass ◽  
Neutrino Oscillations

scholarly journals Unitarity of neutrino mixing matrix

2019 ◽  
Vol 206 ◽  
pp. 09009
Author(s):  
Ha Nguyen Thi Kim ◽  
Van Nguyen Thi Hong ◽  
Son Cao Van
Keyword(s):  
Cp Violation ◽  
Neutrino Oscillations ◽  
Graphical Form ◽  
Muon Neutrinos ◽  
Neutrino Mixing ◽  
Electron Neutrinos ◽  
Tau Neutrinos ◽  
The Matrix ◽  
Mixing Matrix ◽  
Unitary Triangle

Neutrinos are neutral leptons and there exist three types of neutrinos (electron neutrinos νe, muon neutrinos νµ and tau neutrinos ντ). These classifications are referred to as neutrinos’s “flavors”. Oscillations between the different flavors are known as neutrino oscillations, which occurs when neutrinos have mass and non-zero mixing. Neutrino mixing is governed by the PMNS mixing matrix. The PMNS mixing matrix is constructed as the product of three independent rotations. With that, we can describe the numerical parameters of the matrix in a graphical form called the unitary triangle, giving rise to CP violation. We can calculate the four parameters of the mixing matrix to draw the unitary triangle. The area of the triangle is a measure of the amount of CP violation.

NEUTRINOS: LOOKING FORWARD TO THE FUTURE

2007 ◽  
Vol 16 (05) ◽  
pp. 1313-1329
Author(s):  
HISAKAZU MINAKATA
Keyword(s):  
Cp Violation ◽  
Neutrino Mass ◽  
Mass Hierarchy ◽  
Future Prospects ◽  
Neutrino Mass Hierarchy ◽  
Lepton Flavor ◽  
Mixing Parameters ◽  
Wide Range ◽  
Flavor Mixing ◽  
Mass Pattern

I discuss some aspects of future prospects of the experimental exploration of the unknowns in the neutrino mass pattern and the lepton flavor mixing. I start from measuring θ13 by reactors and accelerators as a prerequisite for proceeding to search for leptonic CP violation. I then discuss how CP violation can be uncovered, and how the neutrino mass hierarchy can be determined. I do these by resolving so called the "parameter degeneracy" which is required anyway if one wants to seek precision measurement of the lepton mixing parameters. As a concrete setting for resolving the degeneracy I use the Tokai-to-Kamioka-Korea two detector complex which receives neutrino superbeam from J-PARC, which is sometimes called as "T2KK". It is shown that T2KK is able to resolve all the eight-fold parameter degeneracy in a wide range of the lepton mixing parameters. Some alternative ways of measuring the unknowns are also briefly mentioned.

Sign in / Sign up

Export Citation Format

Share Document