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.

scholarly journals Lepton mass and mixing in a neutrino mass model based onS4flavor symmetry

2016 ◽  
Vol 31 (09) ◽  
pp. 1650039 ◽  
Author(s):  
V. V. Vien
Keyword(s):  
Cp Violation ◽  
Neutrino Mass ◽  
Tree Level ◽  
Neutrino Mixing ◽  
Mass Model ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Neutrino Mass And Mixing ◽  
Model Based ◽  
Mixing Matrix

We study a neutrino mass model based on [Formula: see text] flavor symmetry which accommodates lepton mass, mixing with nonzero [Formula: see text] and CP violation phase. The spontaneous symmetry breaking in the model is imposed to obtain the realistic neutrino mass and mixing pattern at the tree-level with renormalizable interactions. Indeed, the neutrinos get small masses from one [Formula: see text] doublet and two [Formula: see text] singlets in which one being in [Formula: see text] and the two others in [Formula: see text] under [Formula: see text] with both the breakings [Formula: see text] and [Formula: see text] are taken place in charged lepton sector and [Formula: see text] in neutrino sector. The model also gives a remarkable prediction of Dirac CP violation [Formula: see text] or [Formula: see text] in both the normal and inverted spectrum which is still missing in the neutrino mixing matrix. The relation between lepton mixing angles is also represented.

B−L model based on Q4 symmetry for fermion spectrum with normal neutrino mass ordering

2021 ◽  
Vol 36 (07) ◽  
pp. 2150047
Author(s):  
V. V. Vien
Keyword(s):  
Neutrino Mass ◽  
Type I ◽  
Effective Parameters ◽  
Seesaw Mechanism ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Quark Sector ◽  
The Standard Model ◽  
Experimental Values

We propose a renormalizable gauge [Formula: see text] extension of the Standard Model (SM) based on [Formula: see text] symmetry and an auxiliary [Formula: see text] symmetry which can explain the observed quark and lepton masses and mixing angles associated to normal neutrino mass ordering through type-I seesaw mechanism. The relation between the atmospheric mixing angle [Formula: see text] and the effective parameters in neutrino sector is analyzed. Two Majorana phases are predicted to be [Formula: see text] and [Formula: see text] and the model also predicts the effective neutrino mass parameters of [Formula: see text], [Formula: see text] which is well consistent with the planning of future experiments. In the quark sector, the model is predictive since it has ten effective parameters that allow to successfully reproduce the experimental values of the experimental values of the ten physical observables of the quark sector.

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 A discrete anatomy of the neutrino mass matrix

2014 ◽  
Vol 29 (33) ◽  
pp. 1450179
Author(s):  
G. K. Leontaris ◽  
N. D. Vlachos
Keyword(s):  
Finite Group ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Current Data ◽  
Neutrino Mass Matrix ◽  
Linear Combinations ◽  
Mixing Angle ◽  
Mass Matrices ◽  
Mixing Matrix ◽  
Charged Leptons

We investigate the possibility of expressing the charged leptons and neutrino mass matrices as linear combinations of elements of a single finite group. Constraints imposed on the resulting mixing matrix by current data restrict the group types, but allow a nonzero value for the θ13 mixing angle.

scholarly journals Type II seesaw origin of nonzero θ13, δCP and leptogenesis

2014 ◽  
Vol 29 (22) ◽  
pp. 1450108 ◽  
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Type I ◽  
Type Ii ◽  
Mixing Angle ◽  
Yukawa Couplings ◽  
Minimal Structure ◽  
Reactor Mixing ◽  
The Universe

We discuss the possible origin of nonzero reactor mixing angle θ13 and Dirac CP phase δ CP in the leptonic sector from a combination of type I and type II seesaw mechanisms. Type I seesaw contribution to neutrino mass matrix is of tri-bimaximal (TBM) type which gives rise to vanishing θ13 leaving the Dirac CP phase undetermined. If the Dirac neutrino mass matrix is assumed to take the diagonal charged lepton (CL) type structure, such a TBM type neutrino mass matrix originating from type I seesaw corresponds to real values of Dirac Yukawa couplings in the terms [Formula: see text]. This makes the process of right-handed heavy neutrino decay into a light neutrino and Higgs (N → νH) CP preserving ruling out the possibility of leptogenesis. Here we consider the type II seesaw term as the common origin of nonzero θ13 and δ CP by taking it as a perturbation to the leading order TBM type neutrino mass matrix. First, we numerically fit the type I seesaw term by taking oscillation as well as cosmology data and then compute the predictions for neutrino parameters after the type II seesaw term is introduced. We consider a minimal structure of the type II seesaw term and check whether the predictions for neutrino parameters lie in the 3σ range. We also compute the predictions for baryon asymmetry of the universe by considering type II seesaw term as the only source of CP violation and compare it with the latest cosmology data.

scholarly journals TEXTURE-ZERO MODEL FOR THE LEPTON MASS MATRICES

2012 ◽  
Vol 27 (28) ◽  
pp. 1250159 ◽  
Author(s):  
P. M. FERREIRA ◽  
L. LAVOURA
Keyword(s):  
Mass Spectrum ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Type I ◽  
Mixing Angle ◽  
Mass Matrices ◽  
Neutrino Mass Spectrum ◽  
Texture Zero ◽  
Vanishing Elements ◽  
Reactor Mixing

We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and Meμ = 0 (M is the effective light-neutrino Majorana mass matrix). We show that these predictions agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if m3 = 0, provided the Dirac phase δ is very close to maximal (±π/ 2). In the case of a normal neutrino mass spectrum, i.e. when m1 = 0, the agreement of our model with the data is imperfect — the reactor mixing angle θ13 is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.

scholarly journals CHARGED LEPTON CORRECTION TO TRI-BIMAXIMAL LEPTON MIXING AND ITS IMPLICATIONS TO NEUTRINO PHENOMENOLOGY

2013 ◽  
Vol 28 (31) ◽  
pp. 1350131 ◽  
Author(s):  
SRINU GOLLU ◽  
K. N. DEEPTHI ◽  
R. MOHANTA
Keyword(s):  
Charged Lepton ◽  
Daya Bay ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Quark Sector ◽  
Mass Matrices ◽  
Reactor Neutrino ◽  
Mixing Matrix ◽  
Neutrino Experiments ◽  
Reactor Mixing

The recent results from Daya Bay and RENO reactor neutrino experiments have firmly established that the smallest reactor mixing angle θ13 is nonvanishing at the 5 σ level, with a relatively large value, i.e. θ13 ≈ 9°. Using the fact that the neutrino mixing matrix can be represented as [Formula: see text], where Ul and Uν result from the diagonalization of the charged lepton and neutrino mass matrices and Pν is a diagonal matrix containing the Majorana phases and assuming the tri-bimaximal (TBM) form for Uν, we investigate the possibility of accounting for the large reactor mixing angle due to the corrections of the charged lepton mixing matrix. The form of Ul is assumed to be that of CKM mixing matrix of the quark sector. We find that with this modification it is possible to accommodate the large observed reactor mixing angle θ13. We also study the implications of such corrections on the other phenomenological observables.

Neutrinoless double-beta decays: New insights

2017 ◽  
Vol 32 (14) ◽  
pp. 1730011 ◽  
Author(s):  
Z. Z. Xing ◽  
Z. H. Zhao
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Three Dimensional ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Two Dimensional ◽  
Mixing Angles ◽  
Flavor Mixing ◽  
Majorana Neutrino Mass ◽  
Beta Decays

We give some new insights into the effective Majorana neutrino mass [Formula: see text] responsible for the neutrinoless double-beta [Formula: see text] decays. We put forward a three-dimensional way of plotting [Formula: see text] against the lightest neutrino mass and the Majorana phases, which can provide more information as compared with the two-dimensional one. With the help of such graphs we discover a novel threshold of [Formula: see text] in terms of the neutrino masses and flavor mixing angles: [Formula: see text] in connection with [Formula: see text] and [Formula: see text], which can be used to signify observability of the future [Formula: see text]-decay experiments. Fortunately, the possibility of [Formula: see text] turns out to be very small, promising a hopeful prospect for the [Formula: see text]-decay searches.

THE 2–3 SYMMETRY AND LARGE REACTOR MIXING ANGLE

2013 ◽  
Vol 28 (33) ◽  
pp. 1330030 ◽  
Author(s):  
AHMED RASHED ◽  
ALAKABHA DATTA
Keyword(s):  
Symmetry Breaking ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Higgs Doublet ◽  
Mixing Angle ◽  
Neutrino Sector ◽  
Muon Mass ◽  
Symmetric Structure ◽  
Reactor Mixing

We introduce a 2–3 symmetric structure of the charged lepton mass matrix except for one breaking by the muon mass. Symmetry breaking effects are provided both in the charged lepton and the neutrino sector to produce corrections to the leptonic mixing and explain the recent θ13 measurements. A model that extends the SM by three right-handed neutrinos, an extra Higgs doublet, and multi-singlet scalars is introduced to generate the leptonic mixing.

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.

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