scholarly journals TWO/THREE-FLAVOR OSCILLATION AND MSW/VACUUM OSCILLATION SOLUTION OF NEUTRINOS IN THE SO(3) GAUGE MODEL

1999 ◽  
Vol 14 (27) ◽  
pp. 4313-4329 ◽  
Author(s):  
YUE-LIANG WU
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Atmospheric Neutrino ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Gauge Model ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Flavor Oscillation

Three interesting scenarios for neutrino mixing, i.e. (i) small-large mixing scenario, (ii) nearly bi-maximal mixing scenario and (iii) three-flavor oscillation scenario, are analyzed in connection with three possible assignments of the maximal CP-violating phase after spontaneous symmetry breaking of SO(3) in the model with gauged SO(3) lepton flavor symmetry. As a consequence, it is found that the scenario (ii) is more reliable to be constructed to reconcile both solar and atmospheric neutrino data. Though three Majorana neutrino masses in all scenarios can be nearly degenerate, in the scenarios (ii) and (iii) masses of the neutrinos are allowed to be large enough to play a significant cosmological role and in the scenario (i) the fraction Ων/Ωm is bounded to be Ων/Ωm<(1.8-4.5)% for Ωm=(1.0-0.4) and h=0.6.

Discriminating Majorana neutrino phases in the light of lepton flavor violation and leptogenesis in type I+II seesaw models

2015 ◽  
Vol 30 (22) ◽  
pp. 1550130 ◽  
Author(s):  
Rupam Kalita ◽  
Debasish Borah
Keyword(s):  
Mass Matrix ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Type I ◽  
Type Ii ◽  
Lepton Flavor Violation ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Best Fit

We study the effects of Majorana neutrino phases in lepton flavor violation and the origin of matter–antimatter asymmetry through the mechanism of leptogenesis within the framework of a model where both type I and type II seesaw mechanisms can contribute to tiny neutrino masses. We parametrize the type I seesaw mass matrix by assuming it to give rise to a tri-bimaximal (TBM) type neutrino mixing which predicts [Formula: see text]. The type II seesaw mass matrix is then constructed in such a way that the necessary deviation from TBM mixing and the best fit values of neutrino parameters can be obtained when both type I and type II seesaw contributions are taken into account. Considering both subleading as well as equally dominating type II seesaw term, we first constrain the Majorana CP phases from the requirement of producing correct baryon asymmetry through leptogenesis and then incorporating the experimental bounds on lepton flavor violating decays [Formula: see text] and [Formula: see text].

scholarly journals Structure of flavor changing Goldstone boson interactions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jin Sun ◽  
Yu Cheng ◽  
Xiao-Gang He
Keyword(s):  
Symmetry Breaking ◽  
Model Building ◽  
Neutral Current ◽  
Goldstone Boson ◽  
New Physics ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Type I ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current

Abstract General flavor changing Goldstone boson (GB) interactions with fermions from a spontaneous global U(1)G symmetry breaking are discussed. This GB may be the Axion, solving the strong QCD CP problem, if there is a QCD anomaly for the assignments of quarks U(1)G charge. Or it may be the Majoron, producing seesaw Majorana neutrino masses by lepton number violation, if the symmetry breaking scale is much higher than the electroweak scale. It may also, in principle, play the roles of Axion and Majoron simultaneously as far as providing solution for the strong CP problem and generating a small Majorana neutrino masses are concerned. Great attentions have been focused on flavor conserving GB interactions. Recently flavor changing Axion and Majoron models have been studied in the hope to find new physics from rare decays in the intensity frontier. In this work, we will provide a systematic model building aspect study for flavor changing neutral current (FCNC) GB interactions in the fermion sectors, or separately in the quark, charged lepton and neutrino sectors and will identify in detail the sources of FCNC interactions in a class of beyond standard model with a spontaneous global U(1)G symmetry breaking. We also provide a general proof of the equivalence of using physical GB components and GB broken generators for calculating GB couplings to two gluons and two photons, and discuss some issues related to spontaneous CP violation models. Besides, we will also provide some details for obtaining FCNC GB interactions in several popular models, such as the Type-I, -II, -III seesaw and Left-Right symmetric models, and point out some special features in these models.

scholarly journals Neutrino mixings as a source of lepton flavor violations

2018 ◽  
Vol 33 (32) ◽  
pp. 1850201
Author(s):  
O. M. Boyarkin ◽  
G. G. Boyarkina ◽  
D. S. Vasileuskaya
Keyword(s):  
Branching Ratios ◽  
Point Of View ◽  
Heavy Neutrino ◽  
Neutrino Masses ◽  
Symmetric Model ◽  
Neutrino Mixing ◽  
Third Order ◽  
Neutrino Sector ◽  
Lepton Flavor ◽  
Flavor Violations

Within the left–right symmetric model (LRM) the [Formula: see text] boson decay into the channel [Formula: see text] are investigated. The branching ratios of this decay is found in the third order of the perturbation theory. The obtained expression does not equal to zero only at the existence of the neutrino mixings. This means that from the point of view of the LRM, the nonconservations of the neutral and the charged lepton flavors have the same nature. As a result, the elucidation of the decays [Formula: see text] [Formula: see text] could provide data concerned the neutrino sector structure of the LRM. The neutrino sector parameters which could be measured in that case are as follows: (i) difference of the heavy neutrino masses; (ii) heavy–heavy neutrino mixing; (iii) heavy–light neutrino mixing.

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.

Flavons and LFV decays and productions of pseudoscalar mesons

2019 ◽  
Vol 34 (35) ◽  
pp. 1950288
Author(s):  
Tian-Qi Li ◽  
Chong-Xing Yue
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Flavor Symmetry ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Pseudoscalar Mesons ◽  
The Standard Model

Flavons are the dynamic agent of flavor symmetry breaking and have flavor changing couplings to the Standard Model (SM) fermions. We consider their contributions to the lepton flavor violating (LFV) decays [Formula: see text] and [Formula: see text] with [Formula: see text], [Formula: see text] or [Formula: see text] and [Formula: see text] in the simplest flavon model without Higgs-flavon mixing. We find that flavons can produce significant contributions to some of these LFV decay processes.

scholarly journals Investigating the Hybrid Textures of Neutrino Mass Matrix for Near Maximal Atmospheric Neutrino Mixing

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Madan Singh
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Zero Element ◽  
Majorana Neutrino ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
The Comparative Study ◽  
Reactor Mixing ◽  
Majorana Neutrino Mass

We have studied that the implication of a large value of the effective Majorana neutrino mass in case of neutrino mass matrices has either two equal elements and one zero element (popularly known as hybrid texture) or two equal cofactors and one zero minor (popularly known as inverse hybrid texture) in the flavor basis. In each of these cases, four out of sixty phenomenologically possible patterns predict near maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. This feature remains irrespective of the experimental data on solar and reactor mixing angles. In addition, we have also performed the comparative study of all the viable cases of hybrid and inverse hybrid textures at 3σ CL.

BARYOGENESIS IN AN SO(10) GUT MODEL WITH PATI–SALAM INTERMEDIATE SYMMETRY

1998 ◽  
Vol 13 (19) ◽  
pp. 1539-1546
Author(s):  
F. BUCCELLA ◽  
O. PISANTI ◽  
L. ROSA
Keyword(s):  
Experimental Data ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Neutrino Oscillations ◽  
Baryon Asymmetry ◽  
Gauge Model ◽  
Electroweak Scale ◽  
Proton Lifetime ◽  
The Universe ◽  
Breaking Scale

The possibility of generating the observed baryon asymmetry of the universe in an SO(10) gauge model with spontaneous symmetry breaking pattern [Formula: see text] is studied. We find it possible to generate a [Formula: see text], converting the leptonic number produced at the B- L breaking scale via the B+L violating processes mediated by sphalerons at the electroweak scale. The resulting picture is tested against the limit coming from experimental data: proton lifetime and neutrino oscillations.

WHAT DOES μ - τ SYMMETRY IMPLY ABOUT LEPTONIC CP VIOLATION?

2007 ◽  
Vol 16 (05) ◽  
pp. 1373-1381 ◽  
Author(s):  
TEPPEI BABA
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Symmetry Breaking ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Difference ◽  
Atmospheric Neutrino ◽  
Symmetric Part ◽  
Neutrino Mixing ◽  
Mixing Angles

The μ - τ symmetry can reproduce the consistent results with experimental data of θ13, and θ23 (θ13, and θ23 respectively denote the νe - ντ, and νμ - ντ, mixing angles). However, we can not address the issue of the leptonic CP violation in μ - τ symmetric models. So we add the μ - τ symmetry breaking part to include the CP violation. We characterize leptonic CP violation in terms of three phases, where one is conventional phase δ and others are additional phases ρ and γ. These δ, ρ and γ are, respectively, the phases of νe - ντ, νe - νμ and νμ - ντ mixings. The ρ and γ are redundant but the effect of ρ remains in the leptonic CP violation which is characterized by δ + ρ. The δ arises from the μ - τ symmetry breaking part of the Meμ and Meτ while ρ arises from of μ - τ symmetric part of the Meμ and Meτ, where Mij stands for ij (i,j = e,μ,τ) element of M(= [Formula: see text] for Mν being a flavor neutrino mass matrix). Moreover, θ23 can be exactly estimated to be: [Formula: see text] ( sin θ ∝ sin θ13 cos (δ + ρ)[Formula: see text], sin ϕ ∝ Mμμ - Mττ, where [Formula: see text] is the solar neutrino mass difference squared). The conditions of maximal atmospheric neutrino mixing are given by [Formula: see text] and Mμμ = Mττ,which indicate maximal Dirac CP violation.

Cobimaximal neutrino mixing in the U(1)B−L extension with A4 symmetry

2020 ◽  
Vol 35 (38) ◽  
pp. 2050311
Author(s):  
V. V. Vien
Keyword(s):  
Beta Decay ◽  
Atmospheric Neutrino ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Tree Level ◽  
Physical Parameters ◽  
Neutrino Masses ◽  
Type I ◽  
Neutrino Mixing ◽  
Best Fit

We propose a renormalizable [Formula: see text] extension of the Standard model with [Formula: see text] symmetry that leads to the successful cobimaximal lepton mixing ansatz, thus providing a predictive explanation for leptonic mixing observables. The smallness of the active neutrino masses and neutrino masses ordering are produced by the type-I seesaw mechanism at the tree-level. The obtained physical parameters are well consistent with the global fit of neutrino oscillation.1 The model is predictive in the sense that it reproduces the experimental values of neutrino parameters in which the reactor neutrino mixing angle [Formula: see text] get the best-fit value and the solar and atmospheric neutrino mixing angles have little deviations from the best-fit values given in Ref. 1, however, they are consistent with the other experimental results.[Formula: see text] The effective neutrino masses governing the neutrinoless double beta decay is predicted to be [Formula: see text] for normal hierarchy and [Formula: see text] for inverted hierarchy which are well consistent with the recent experimental limits on neutrinoless double beta decay.

scholarly journals Dirac or inverse seesaw neutrino masses from gauged B–L symmetry

2015 ◽  
Vol 30 (26) ◽  
pp. 1530020 ◽  
Author(s):  
Ernest Ma ◽  
Rahul Srivastava
Keyword(s):  
Standard Model ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Free Solution ◽  
Neutrino Mixing ◽  
Seesaw Mechanism

The gauged [Formula: see text] symmetry is one of the simplest and well-studied extension of Standard Model. In the conventional case, addition of three singlet right-handed neutrinos each transforming as [Formula: see text] under the [Formula: see text] symmetry renders it anomaly-free. It is usually assumed that the [Formula: see text] symmetry is spontaneously broken by a singlet scalar having two units of [Formula: see text] charge, resulting in a natural implementation of Majorana seesaw mechanism for neutrinos. However, as we discuss here, there is another simple anomaly-free solution which leads to Dirac or inverse seesaw masses for neutrinos. These new possibilities are explored along with an application to neutrino mixing with [Formula: see text] flavor symmetry.

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