Neutrino Masses and Mixing

2003 ◽  
Vol 214 ◽  
pp. 347-356
Author(s):  
Yoji Totsuka
Keyword(s):  
Neutrino Oscillations ◽  
Solar And Atmospheric Neutrinos ◽  
Convincing Evidence ◽  
Neutrino Masses ◽  
Atmospheric Neutrinos ◽  
Mixing Angle ◽  
Mixing Angles ◽  
The One ◽  
Quark Flavors

Recent results on neutrino masses and mixing are presented. There is convincing evidence for nonzero but tiny masses of at least two flavor neutrinos, based on two types of neutrino oscillations, solar and atmospheric neutrinos. The large mixing angle between first and second flavors and also the one between the second and third flavors were found, quite contrary to small mixing angles among quark flavors, and pose a new mystery.

scholarly journals ONE-PION EVENTS BY ATMOSPHERIC NEUTRINOS: A THREE-FLAVOR ANALYSIS

2001 ◽  
Vol 16 (08) ◽  
pp. 1417-1429 ◽  
Author(s):  
K. R. S. BALAJI ◽  
G. RAJASEKARAN ◽  
S. UMA SANKAR
Keyword(s):  
Diagnostic Method ◽  
Neutrino Oscillations ◽  
Neutral Current ◽  
Charged Current ◽  
Atmospheric Neutrinos ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Flavor Oscillations ◽  
Flavor Analysis ◽  
The One

We study the one-pion events produced via neutral current (NC) and charged current (CC) interactions by the atmospheric neutrinos. We analyze the ratios of CC events to the NC events in the framework of neutrino oscillations. These ratios can distinguish between different combinations of neutrino mixing angles in the case of three-flavor oscillations. They also provide a good diagnostic method to distinguish νμ→ντ oscillations from νμ→νs oscillations.

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.

Texture zero mass matrices and flavor mixing of quarks and leptons

2015 ◽  
Vol 30 (28) ◽  
pp. 1550138 ◽  
Author(s):  
Harald Fritzsch
Keyword(s):  
Experimental Data ◽  
Neutrino Masses ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Zero Mass ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Texture Zero ◽  
The Masses

We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: [Formula: see text], [Formula: see text] and [Formula: see text].

scholarly journals Reinterpreting the ATLAS bounds on heavy neutral leptons in a realistic neutrino oscillation model

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
J.-L. Tastet ◽  
O. Ruchayskiy ◽  
I. Timiryasov
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Oscillations ◽  
Realistic Model ◽  
Model Parameters ◽  
Exclusion Limit ◽  
Final State ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Oscillation Model ◽  
Free Parameters

Abstract Heavy neutral leptons (HNLs) are hypothetical particles, motivated in the first place by their ability to explain neutrino oscillations. Experimental searches for HNLs are typically conducted under the assumption of a single HNL mixing with a single neutrino flavor. However, the resulting exclusion limits may not directly constrain the corresponding mixing angles in realistic HNL models — those which can explain neutrino oscillations. The reinterpretation of the results of these experimental searches turns out to be a non-trivial task, that requires significant knowledge of the details of the experiment. In this work, we perform a reinterpretation of the latest ATLAS search for HNLs decaying promptly to a tri-lepton final state. We show that in a realistic model with two HNLs, the actual limits can vary by several orders of magnitude depending on the free parameters of the model. Marginalizing over the unknown model parameters leads to an exclusion limit on the total mixing angle which can be up to 3 orders of magnitude weaker than the limits reported in ref. [1]. This demonstrates that the reinterpretation of results from experimental searches is a necessary step to obtain meaningful limits on realistic models. We detail a few steps that can be taken by experimental collaborations in order to simplify the reuse of their results.

scholarly journals Sum rules for leptons

2016 ◽  
Vol 31 (17) ◽  
pp. 1630021 ◽  
Author(s):  
Martin Spinrath
Keyword(s):  
Renormalization Group ◽  
Symmetry Breaking ◽  
Wide Class ◽  
Sum Rules ◽  
The Other ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
The One ◽  
Dynamical Description ◽  
The Impact

There is a wide class of models which give a dynamical description of the origin of flavor in terms of spontaneous symmetry breaking of an underlying symmetry. Many of these models exhibit sum rules which relate on the one hand mixing angles and the Dirac CP phase with each other and/or on the other hand neutrino masses and Majorana phases with each other. We will briefly sketch how this happens and discuss briefly the impact of renormalization group corrections to the mass sum rules.

scholarly journals Relating lepton mixing angles with lepton mass hierarchy

2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650002
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Mass Matrices ◽  
Model Independent ◽  
The Difference

We revisit the possibility of relating lepton mixing angles with lepton mass hierarchies in a model-independent way. Guided by the existence of such relations in the quark sector, we first consider all the mixing angles, both in charged lepton and neutrino sectors to be related to the respective mass ratios. This allows us to calculate the leptonic mixing angles observed in neutrino oscillations as functions of the lightest neutrino mass. We show that for both normal and inverted hierarchical neutrino masses, this scenario does not give rise to correct leptonic mixing angles. We then show that correct leptonic mixing angles can be generated with normal hierarchical neutrino masses if the relation between mixing angle and mass ratio is restricted to 1–2 and 1–3 mixing in both charged lepton and neutrino sectors leaving the 2–3 mixing angles as free parameters. We then restrict the lightest neutrino mass as well as the difference between 2–3 mixing angles in charged lepton and neutrino sectors from the requirement of producing correct leptonic mixing angles. We constrain the lightest neutrino mass to be around 0.002 eV and leptonic Dirac CP phase [Formula: see text] such that [Formula: see text]. We also construct the leptonic mass matrices in terms of 2–3 mixing angles and lightest neutrino mass and briefly comment on the possibility of realizing texture zeros in the neutrino mass matrix.

scholarly journals FLAVOR MIXING, QUARK MASSES, NEUTRINO MASSES AND NEUTRINO OSCILLATIONS

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3354-3358 ◽  
Author(s):  
H. FRITZSCH
Keyword(s):  
Neutrino Masses ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Quark Masses ◽  
Mass Matrices ◽  
Mass Ratios ◽  
Flavor Mixing ◽  
Eigen Values ◽  
Charged Leptons ◽  
The Masses

We study a model for the mass matrices of the quarks and leptons. Two of the three flavor mixing angles of the quarks can be calculated in terms of the quark mass ratios. They agree very well with the experiments. We are able to relate the mass eigen values of the charged leptons and of the neutrinos to the mixing angles and can predict the masses of the neutrinos. We find a normal hierarchy -the masses are 0.004 eV, 0.01 eV and 0.05 eV. The atmospheric mixing angle is given by the mass ratios of the charged leptons and the neutrinos. We find 38 degrees, consistent with the experiments. The mixing element, connecting the first neutrino with the electron, is found to be 0.05.

NEUTRINO OSCILLATIONS: DISCOVERY, CURRENT STATUS, FUTURE DIRECTIONS

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3437-3446 ◽  
Author(s):  
TAKAAKI KAJITA
Keyword(s):  
Neutrino Oscillation ◽  
Present Status ◽  
Neutrino Oscillations ◽  
Future Prospect ◽  
Current Status ◽  
Neutrino Masses ◽  
Future Directions ◽  
Mixing Angles ◽  
The Future

Neutrino oscillation was discovered about 10 years ago. Since then, the knowledge on neutrino masses and mixing angles have been improving substantially. This article describes neutrino oscillation experiments; the discovery, the present status and the future prospect.

scholarly journals FINALLY NEUTRINO HAS MASS

2000 ◽  
Vol 15 (05) ◽  
pp. 625-650 ◽  
Author(s):  
S. M. BILENKY ◽  
C. GIUNTI ◽  
C. W. KIM
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Solar Neutrino ◽  
Present Status ◽  
Neutrino Oscillations ◽  
Neutrino Masses ◽  
Atmospheric Neutrinos ◽  
Neutrino Experiments

The present status of the problem of neutrino mass, mixing and neutrino oscillations is briefly summarized. The evidence for oscillations of atmospheric neutrinos found recently in the Super-Kamiokande experiment is discussed. Indications in favor of neutrino oscillations obtained in solar neutrino experiments and in the accelerator LSND experiment are also considered. Implications of existing neutrino oscillation data for neutrino masses and mixing are discussed.

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