scholarly journals Small 𝜃13 and solar neutrino oscillation parameters from μ − τ symmetry

2021 ◽  
Author(s):  
Abdel Pérez-Lorenzana
Keyword(s):  
Neutrino Oscillation ◽  
Solar Neutrino ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Majorana Neutrino ◽  
Neutrino Mixing ◽  
Mass Eigenstates ◽  
Reactor Neutrino ◽  
Exact Symmetry ◽  
Majorana Neutrino Mass

Exchange [Formula: see text] symmetry in the effective Majorana neutrino mass matrix does predict a maximal mixing for atmospheric neutrino oscillations asides to a null mixing that cannot be straightforwardly identified with reactor neutrino oscillation mixing, [Formula: see text], unless a specific ordering is assumed for the mass eigenstates. Otherwise, a nonzero value for [Formula: see text] is predicted already at the level of an exact symmetry. In this case, solar neutrino mixing and scale, as well as the correct atmospheric mixing arise from the breaking of the symmetry. I present a mass matrix proposal for normal hierarchy that realizes this scenario, where the smallness of [Formula: see text] is naturally given by the parameter [Formula: see text] and the solar mixing is linked to the smallness of [Formula: see text]. The proposed matrix remains stable under renormalization effects and it also allows to account for CP violation within the expected region without further constrains.

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.

scholarly journals IS Ue3 REALLY RELATED TO THE SOLAR NEUTRINO SOLUTIONS?

2000 ◽  
Vol 15 (37) ◽  
pp. 2257-2263
Author(s):  
N. HABA ◽  
TOMOHARU SUZUKI
Keyword(s):  
Physical Parameter ◽  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Solar Neutrino ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Lepton Flavor ◽  
Flavor Mixing ◽  
Mixing Matrix ◽  
Majorana Neutrino Mass

It is important to measure Ue3 in the lepton flavor mixing matrix in order to understand the structure of Majorana neutrino mass matrix. Recently it is conjectured that the measurement of Ue3 would discriminate one solution among various solar neutrino ones provided that the three mass eigenvalues of neutrinos have the relation m1≪m2≪m3 or m1~m2≪m3. In this letter we show that this conjecture is rather restrictive and the relation [Formula: see text] is derived by a nontrivial assumption and Ue3 cannot discriminate among solar neutrino oscillation solutions without the information on another physical parameter.

scholarly journals BIMAXIMAL MIXINGS FROM THE TEXTURE OF THE RIGHT-HANDED MAJORANA NEUTRINO MASS MATRIX

2002 ◽  
Vol 17 (25) ◽  
pp. 3629-3640 ◽  
Author(s):  
N. NIMAI SINGH ◽  
MAHADEV PATGIRI
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Majorana Neutrino ◽  
Neutrino Mass Matrix ◽  
Diagonal Form ◽  
Dirac Neutrino ◽  
Mass Matrices ◽  
The Right ◽  
Majorana Neutrino Mass

We study the origin of neutrino masses and mixing angles which can accommodate the LMA MSW solutions of the solar neutrino anomaly as well as the solution of the atmospheric neutrino problem, within the framework of the see-saw mechanism. We employ the diagonal form of the Dirac neutrino mass matrices with the physical masses as diagonal elements in the hierarchical order. Such a choice has been motivated from the fact that the known CKM angles for the quark sector, are relatively small. We consider both possibilities where the Dirac neutrino mass matrix is either the charged lepton or the up-quark mass matrix within the framework of SO(10) GUT with or without supersymmetry. The nonzero texture of the right-handed Majorana neutrino mass matrix M R is used for the generation of the desired bimaximal mixings in a model independent way. Both hierarchical and inverted hierarchical models of the left-handed Majorana neutrino mass matrices are generated and then discussed with examples. The see-saw mass scale which is kept as a free parameter, is predicted in all the examples.

scholarly journals Effective Neutrino Masses from Four Flavor Neutrino Mixing Matrix

2021 ◽  
Author(s):  
Bipin Singh Koranga ◽  
Vivek Kumar Nautiyal
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Upper Bound ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Mixing Parameters ◽  
Normal Mass ◽  
Mixing Matrix ◽  
Majorana Neutrino Mass

AbstractWe consider the four neutrino oscillation that accommodate the all neutrino oscillation data. We consider the range of the corresponding mixing parameters by the result of neutrino oscillation experiments. Implicaion of the neutrino oscillation search for the neutrino mass square difference and mixing are discussed. We determine the possible values of the effective majorana neutrino mass $|<m>|=|{\sum }_{j}U_{ej}^{2}m_{j}|$ | < m > | = | ∑ j U e j 2 m j | in the four neutrino scenario. In the four-neutrino scheme there is an upper bound on | < m > | of the normal mass order is 2.0074eV for α = 0∘,β = 0∘andγ = 0∘. In the case of inverted mass order the upper bound on | < m > | is 2.0069eV for α = 0∘,β = 0∘andγ = 0∘.

scholarly journals Predictions for the neutrino parameters in the minimal model extended by linear combination of U(1)$$_{L_e-L_\mu }$$, U(1)$$_{L_\mu -L_\tau }$$ and U(1)$$_{B-L}$$ gauge symmetries

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Kento Asai
Keyword(s):  
Linear Combination ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Neutrino Mixing ◽  
Minimal Models ◽  
Mixing Angles ◽  
Lepton Flavor ◽  
Gauge Symmetries ◽  
Mass Matrices ◽  
Majorana Neutrino Mass

Abstract We study the minimal extensions of the Standard Model by a linear combination of U(1)$$_{L_e-L_\mu }$$Le-Lμ, U(1)$$_{L_\mu -L_\tau }$$Lμ-Lτ and U(1)$$_{B-L}$$B-L gauge symmetries, where three right-handed neutrinos and one U(1)-breaking SU(2)$$_L$$L singlet or doublet scalar are introduced. Because of the dependence on the lepton flavor, the structures of both Dirac and Majorana mass matrices of neutrinos are restricted. In particular, the two-zero minor and texture structures in the mass matrix for the active neutrinos are interesting. Analyzing these structures, we obtain uniquely all the neutrino parameters, namely the Dirac CP phase $$\delta $$δ, the Majorana CP phases $$\alpha _{2,3}$$α2,3 and the mass eigenvalues of the light neutrinos $$m_i$$mi as functions of the neutrino mixing angles $$\theta _{12}$$θ12, $$\theta _{23}$$θ23, and $$\theta _{13}$$θ13, and the squared mass differences $$\Delta m^2_{21}$$Δm212 and $$\Delta m^2_{31}$$Δm312. In 7 minimal models which are consistent with the recent neutrino oscillation data, we also obtain the predictions for the sum of the neutrino masses $$\Sigma _i m_i$$Σimi and the effective Majorana neutrino mass $$\langle m_{\beta \beta }\rangle $$⟨mββ⟩ and compare them with the current experimental limits. In addition, we also discuss the implication of our results for leptogenesis.

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 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 Obtaining nonvanishing 𝜃13 with constrained neutrino Yukawa matrix and implications for flavor model buildings

2017 ◽  
Vol 32 (16) ◽  
pp. 1750080
Author(s):  
Ya Zhao
Keyword(s):  
Mass Matrix ◽  
Majorana Neutrino ◽  
Effective Coupling ◽  
Coupling Matrix ◽  
Linear Combinations ◽  
Mixing Angle ◽  
Specific Choice ◽  
Matrix Formula ◽  
Reactor Mixing ◽  
Majorana Neutrino Mass

Assuming a diagonal Majorana neutrino mass matrix, we investigate the neutrino Yukawa textures which lead to a nonzero reactor mixing angle [Formula: see text]. The neutrino effective coupling matrix [Formula: see text] is pre-diagonalized by a constant mixing pattern [Formula: see text] with a vanishing [Formula: see text]. The resulting pre-diagonal symmetrical matrix [Formula: see text] is set to be four texture zeros with two types of off-diagonal elements nonzero, which are [Formula: see text] and [Formula: see text], respectively. With the expectation of simple textures, we thoroughly classify the linear combinations, [Formula: see text], [Formula: see text] and [Formula: see text] of Yukawa elements [Formula: see text] in the same row, according to the values, vanishing or not. Each set of the classifications can lead to a Yukawa texture which may have implications for the discrete flavor model buildings. We also present a model based on [Formula: see text] according to one set of the constraints on the three combinations with a specific choice of a coefficient in Yukawa texture.

scholarly journals ANALYSIS OF NEUTRINO OSCILLATION IN THREE-FLAVOR NEUTRINOS

1999 ◽  
Vol 14 (12) ◽  
pp. 1953-1974 ◽  
Author(s):  
T. SAKAI ◽  
O. INAGAKI ◽  
T. TESHIMA
Keyword(s):  
Neutrino Oscillation ◽  
Zenith Angle ◽  
Small Angle ◽  
Solar Neutrino ◽  
Atmospheric Neutrino ◽  
Large Angle ◽  
Angle Dependence ◽  
Significant Difference ◽  
Neutrino Experiments

We analyze the solar, terrestrial and atmospheric neutrino experiments including SuperKamiokande data using the three-flavor neutrinos framework and obtain the allowed region for parameters [Formula: see text]. In solar neutrino experiments, we obtain the large angle solution [Formula: see text] and small angle solution (3×10-6-1.2×10-5 eV 2, 0.003-0.01) for θ13=0°-20°. From the terrestrial and atmospheric neutrino experiments including the sub-GeV and multi-GeV zenith angle dependence in SuperKamiokande 535 days data, we found that the νμ-ντ mixing is large and the range of [Formula: see text] as 0.02~0.0002  eV 2. There is no significant difference between large θ12 angle solution and small one.

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