scholarly journals FLAVOR MIXING AND CP VIOLATION OF MASSIVE NEUTRINOS

2004 ◽  
Vol 19 (01) ◽  
pp. 1-79 ◽  
Author(s):  
ZHI-ZHONG XING
Keyword(s):  
Cp Violation ◽  
Phenomenological Study ◽  
Double Beta Decay ◽  
Seesaw Mechanism ◽  
Lepton Flavor ◽  
Long Baseline ◽  
Mixing Parameters ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Massive Neutrinos

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

scholarly journals Testing unitarity of the 3 × 3 neutrino mixing matrix in an atomic system

2020 ◽  
Vol 35 (01) ◽  
pp. 2050004
Author(s):  
Guo-Yuan Huang ◽  
Noboru Sasao ◽  
Zhi-Zhong Xing ◽  
Motohiko Yoshimura
Keyword(s):  
Degrees Of Freedom ◽  
Atomic System ◽  
Transition Process ◽  
Photon Spectrum ◽  
Neutrino Mixing ◽  
Seesaw Mechanism ◽  
Lepton Flavor ◽  
Mixing Parameters ◽  
Flavor Mixing ◽  
Mixing Matrix

Unitarity of the [Formula: see text] lepton flavor mixing matrix [Formula: see text] is unavoidably violated in a seesaw mechanism if its new heavy degrees of freedom are slightly mixed with the active neutrino flavors. We propose to use the atomic transition process [Formula: see text] (for [Formula: see text], [Formula: see text]), where [Formula: see text] and [Formula: see text] stand, respectively for the excited and ground levels of an atomic system, to probe or constrain the unitarity-violating effects of [Formula: see text]. We find that the photon spectrum of this transition will be distorted by the effects of [Formula: see text] and [Formula: see text] as compared with the [Formula: see text] case. We locate certain frequencies in the photon spectrum to minimize the degeneracy of effects of the unitarity violation and uncertainties of the flavor mixing parameters themselves. The requirements of a nominal experimental setup to test the unitarity of [Formula: see text] are briefly discussed.

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.

scholarly journals Effect of Sterile Neutrino on Low-Energy Processes in Minimal Extended Seesaw With Δ(96) Symmetry and TM1 Mixing

2021 ◽  
Vol 9 ◽  
Author(s):  
Nayana Gautam ◽  
R. Krishnan ◽  
Mrinal Kumar Das
Keyword(s):  
Sterile Neutrino ◽  
New Physics ◽  
Double Beta Decay ◽  
Tau Leptons ◽  
Lepton Flavor Violation ◽  
Normal Ordering ◽  
Seesaw Mechanism ◽  
Lepton Flavor ◽  
Mass Matrices ◽  
Energy Processes

We study the effect of sterile neutrino on some low-scale processes in the framework of the minimal extended seesaw (MES). MES is the extension of the seesaw mechanism with the addition of sterile neutrino of intermediate mass. The MES model in this work is based on Δ(96) × C2 × C3 flavor symmetry. The structures of mass matrices in the framework lead to TM1 mixing with μ–τ symmetry. The model predicts the maximal value of the Dirac CP phase. We carry out our analysis to study the new physics contributions from the sterile neutrino to different charged lepton flavor violation (cLFV) processes involving muon and tau leptons as well as neutrinoless double beta decay (0νββ). The model predicts normal ordering (NO) of neutrino masses, and we perform the numerical analysis considering normal ordering (NO) only. We find that a heavy sterile neutrino can lead to cLFV processes that are within the reach of current and planned experiments. The sterile neutrino present in our model is consistent with the current limits on the effective neutrino mass set by 0νββ experiments.

scholarly journals THEORETICAL OVERVIEW ON THE FLAVOR ISSUES OF MASSIVE NEUTRINOS

2012 ◽  
Vol 27 (28) ◽  
pp. 1230031 ◽  
Author(s):  
SHU LUO ◽  
ZHI-ZHONG XING
Keyword(s):  
Dipole Moments ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Lepton Flavor ◽  
Mixing Parameters ◽  
Flavor Mixing ◽  
Majorana Neutrinos ◽  
Massive Neutrinos ◽  
The Impact ◽  
Theoretical Overview

We present an overview on some basic properties of massive neutrinos and focus on their flavor issues, including the mass spectrum, flavor mixing pattern and CP violation. The lepton flavor structures are explored by taking into account of the observed value of the smallest neutrino mixing angle θ13. The impact of θ13 on the running behaviors of other flavor mixing parameters is discussed in some detail. The seesaw-induced enhancement of the electromagnetic dipole moments for three Majorana neutrinos is also discussed in a TeV seesaw scenario.

scholarly journals SUM RULES OF FOUR-NEUTRINO MIXING IN MATTER

2007 ◽  
Vol 22 (18) ◽  
pp. 1341-1347 ◽  
Author(s):  
HE ZHANG
Keyword(s):  
Cp Violation ◽  
Sum Rules ◽  
Sterile Neutrino ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Long Baseline ◽  
Mixing Parameters ◽  
Flavor Mixing ◽  
Mixing Matrix ◽  
Model Independent

Assuming the existence of one light sterile neutrino, we investigate the neutrino flavor mixing matrix in matter. Sum rules between the mixing parameters in vacuum and their counterparts in matter are derived. By using these new sum rules, we obtain the simple but exact expressions of the effective flavor mixing matrix in matter in terms of neutrino masses and the mixing parameters in vacuum. The rephasing invariants, sides of unitarity quadrangles and oscillation probabilities in matter are also achieved. Our model-independent results will be very helpful for analyzing flavor mixing and CP violation in the future long-baseline neutrino oscillation experiments.

scholarly journals Minimal scoto-seesaw mechanism with spontaneous CP violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
D. M. Barreiros ◽  
F. R. Joaquim ◽  
R. Srivastava ◽  
J. W. F. Valle
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Seesaw Mechanism ◽  
Cosmological Observations ◽  
Scalar Singlet

Abstract We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $$ {\mathcal{Z}}_8 $$ Z 8 discrete symmetry, broken to a residual $$ {\mathcal{Z}}_2 $$ Z 2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic CP-violating effects. We find that the imposed $$ {\mathcal{Z}}_8 $$ Z 8 symmetry pushes the values of the Dirac CP phase and the lightest neutrino mass to ranges already probed by ongoing experiments, so that normal-ordered neutrino masses can be cornered by cosmological observations and neutrinoless double beta decay experiments.

scholarly journals NEUTRINO MASSES, LEPTON FLAVOR MIXING AND LEPTOGENESIS IN THE MINIMAL SEESAW MODEL

2007 ◽  
Vol 16 (01) ◽  
pp. 1-50 ◽  
Author(s):  
WAN-LEI GUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Seesaw Model ◽  
Flavor Mixing ◽  
Majorana Neutrinos

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

scholarly journals PERTURBED INVARIANT UNDER A CYCLIC PERMUTATION WITH TRACE OF NEUTRINO MASS MATRIX REMAIN CONSTANT

2011 ◽  
Vol 26 (08) ◽  
pp. 567-574 ◽  
Author(s):  
ASAN DAMANIK
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Cyclic Permutation ◽  
Neutrino Mass Matrix ◽  
Neutrino Masses ◽  
Inverted Hierarchy ◽  
Seesaw Mechanism ◽  
Mixing Parameters ◽  
Difference Formula ◽  
Mass Matrices

We construct a neutrino mass matrix Mν via a seesaw mechanism with perturbed invariant under a cyclic permutation by introducing a parameter δ into the diagonal elements of Mν with the assumption that trace of the perturbed Mν is equal to trace of the unperturbed Mν. We found that the perturbed neutrino mass matrices Mν can predict the mass-squared difference [Formula: see text] with the possible hierarchy of neutrino mass is normal or inverted hierarchy. By using the advantages of the mass-squared differences and mixing parameters data from neutrino oscillation experiments, we then have neutrino masses in inverted hierarchy with masses: |m1| = 0.101023 eV , |m2| = 0.101428 eV and |m3| = 0.084413 eV .

scholarly journals Oscillating Neutrinos and Majorana Neutrino Masses

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Harald Fritzsch
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Quark Masses ◽  
Mass Matrices ◽  
The Matrix ◽  
Flavor Mixing

We discuss the mass matrices with texture zeros for the quarks and leptons. The flavor mixing angles for the quarks are functions of the quark masses and can be calculated. The results agree with the experimental data. The texture zero mass matrices for the leptons and the see-saw mechanism are used to derive relations between the matrix elements of the lepton mixing matrix and the ratios of the neutrino masses. Using the measured neutrino mass differences, the neutrino masses can be calculated. The neutrinoless double beta decay is discussed. The effective Majorana neutrino mass, describing the neutrinoless double beta decay, can be calculated—it is about 4.6 meV. The present experimental limit is at least twenty times larger.

Sign in / Sign up

Export Citation Format

Share Document