scholarly journals A systematic analysis of perturbations for hexagonal mixing matrix

2019 ◽  
Vol 34 (01) ◽  
pp. 1950005
Author(s):  
Sumit K. Garg
Keyword(s):  
Neutrino Mixing ◽  
Inverted Hierarchy ◽  
Systematic Analysis ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Angle Data ◽  
Mixing Matrix ◽  
Global Fit ◽  
Pmns Matrix ◽  
The Impact

We present a systematic analysis of perturbative Hexagonal (HG) mixing for describing recent global fit neutrino mixing data with normal and inverted hierarchy. The corrections to unperturbed mixing are parametrized in terms of small orthogonal rotations [Formula: see text] with modified PMNS matrix of the forms [Formula: see text]. Here, [Formula: see text] is rotation in [Formula: see text] sector and [Formula: see text] is unperturbed Hexagonal mixing matrix. The detailed numerical investigation of all possible cases is performed with scanning of parameter space using [Formula: see text] approach. We found that the perturbative schemes governed by single rotation are unable to fit the mixing angle data even at [Formula: see text] level. The mixing schemes which involve two rotation matrices only [Formula: see text] are successful in fitting all neutrino mixing angles within [Formula: see text] range for normal hierarchy (NH). However for inverted hierarchy (IH), only [Formula: see text] is most preferable as it can fit all mixing angles at [Formula: see text] level. The remaining perturbative cases are either excluded at [Formula: see text] level or successful in producing mixing angles only at [Formula: see text] level. To study the impact of phase parameter, we also looked into CP violating effects for single rotation case. The predicted value of [Formula: see text] lies in the range [Formula: see text] for [Formula: see text] and [Formula: see text] case with normal (inverted) hierarchy.

scholarly journals Octant Degeneracy and Quadrant of Leptonic CPV Phase at Long BaselineνExperiments and Baryogenesis

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Kalpana Bora ◽  
Gayatri Ghosh ◽  
Debajyoti Dutta
Keyword(s):  
Numerical Study ◽  
Global Analysis ◽  
Neutrino Mixing ◽  
Inverted Hierarchy ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Long Baseline ◽  
Discovery Potential ◽  
Neutrino Experiments ◽  
Best Fit

In a recent work by us, we have studied how CP violation discovery potential can be improved at long baseline neutrino experiments (LBNE/DUNE), by combining with its ND (near detector) and reactor experiments. In this work, we discuss how this study can be further analysed to resolve entanglement of the quadrant of leptonic CPV phase and octant of atmospheric mixing angleθ23, at LBNEs. The study is done for both NH (normal hierarchy) and IH (inverted hierarchy), HO (higher octant), and LO (lower octant). We show how baryogenesis can enhance the effect of resolving this entanglement and how possible values of the leptonic CP violating phaseδCPcan be predicted in this context. With respect to the latest global fit data of neutrino mixing angles, we predict the values ofδCPfor different cases. In this context we present favoured values ofδCP(δCPrange at ≥2σ) constrained by the latest updated BAU range and also confront our predictions ofδCPwith an up-to-date global analysis of neutrino oscillation data. We find that some region of the favouredδCPparameter space lies within the best fit values aroundδCP≃1.3π–1.4π. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework within the nonsupersymmetric SO(10)models.

scholarly journals 𝜃23 = π/4 and δ = −π/2 in neutrino mixing, which convention?

2019 ◽  
Vol 34 (35) ◽  
pp. 1950235
Author(s):  
Junxing Pan ◽  
Jin Sun ◽  
Xiao-Gang He
Keyword(s):  
Phase Change ◽  
The Other ◽  
Particle Data Group ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Mixing Matrix ◽  
Physical Effects ◽  
Data Group

Considerable information has been obtained about neutrino mixing matrix. Present data show that in the particle data group (PDG) parametrization, the 2–3 mixing angle and the CP violating phase are consistent with [Formula: see text] and [Formula: see text], respectively. A lot of efforts have been devoted to constructing models in realizing a mixing matrix with these values. However, the particular angles and phase are parametrization convention dependent. The meaning about the specific values for mixing angle and phase needs to be clarified. Using the well-known nine independent ways of parametrizing the mixing matrix, we show in detail how the mixing angles and phase change with conventions even with the 2–3 mixing angle to be [Formula: see text] and the CP violating phase to be [Formula: see text]. The original Kobayashi–Maskawa and an additional one belong to such a category. The other 6 parametrizations have mixing angles and phase very different values from those in the PDG parametrization although the physical effects are the same. Therefore one should give the specific parametrization convention when making statements about values for mixing angles and phase.

scholarly journals Effects of Leptonic Nonunitarity on Lepton Flavor Violation, Neutrino Oscillation, Leptogenesis, and Lightest Neutrino Mass

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Gayatri Ghosh ◽  
Kalpana Bora
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Type I ◽  
Lepton Flavor Violation ◽  
Neutrino Mixing ◽  
Inverted Hierarchy ◽  
Planck Data ◽  
Mixing Angles ◽  
Lepton Flavor ◽  
Mixing Matrix

Neutrino physics is a mature branch of science with all the three neutrino mixing angles and two mass squared differences determined with high precision. In spite of several experimental verifications of neutrino oscillations and precise measurements of two mass squared differences and the three mixing angles, the unitarity of the leptonic mixing matrix is not yet established, leaving room for the presence of small nonunitarity effects. Deriving the bounds on these nonunitarity parameters from existing experimental constraints, on cLFV decays such as μ→eγ, μ→τγ, and τ→eγ, we study their effects on the generation of baryon asymmetry through leptogenesis and neutrino oscillation probabilities. We consider a model where see-saw is extended by an additional singlet S which is very light but can give rise to nonunitarity effects without affecting the form on see-saw formula. We do a parameter scan of a minimal see-saw model in a type I see-saw framework satisfying the Planck data on baryon to photon ratio of the Universe, which lies in the interval 5.8×10-10<YB<6.6×10-10(BBN). We predict values of lightest neutrino mass and Dirac and Majorana CP-violating phases δCP, α, and β, for normal hierarchy and inverted hierarchy for one-flavor leptogenesis. It is worth mentioning that all these four quantities are unknown yet, and future experiments will be measuring them.

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 Parametrization of Pontecorvo–Maki–Nakagawa–Sakata mixing matrix based on CP-violating bipair neutrino mixing

2015 ◽  
Vol 30 (05) ◽  
pp. 1550019 ◽  
Author(s):  
Jun Iizuka ◽  
Teruyuki Kitabayashi ◽  
Yuki Minagawa ◽  
Masaki Yasuè
Keyword(s):  
Matrix Element ◽  
Cp Violation ◽  
Numerical Computation ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Neutrino Interactions ◽  
Reactor Neutrino ◽  
Mixing Matrix ◽  
Three Phases

CP violation in neutrino interactions is described by three phases contained in Pontecorvo–Maki–Nakagawa–Sakata mixing matrix (U PMNS ). We argue that the phenomenologically consistent result of the Dirac CP violation can be obtained if U PMNS is constructed along bipair neutrino mixing scheme, namely, requiring that |U12| = |U32| and |U22| = |U23| (case 1) and |U12| = |U22| and |U32| = |U33| (case 2), where Uij stands for the i × j matrix element of U PMNS . As a result, the solar, atmospheric and reactor neutrino mixing angles θ12, θ23 and θ13, respectively, are correlated to satisfy cos 2θ12 = sin 2 θ23 - tan 2 θ13 (case 1) or cos 2θ12 = cos 2 θ23 - tan 2 θ13 (case 2). Furthermore, if Dirac CP violation is observed to be maximal, θ23 is determined by θ13 to be: [Formula: see text] (case 1) or [Formula: see text] (case 2). For the case of non-maximal Dirac CP violation, we perform numerical computation to show relations between the CP-violating Dirac phase and the mixing angles.

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.

scholarly journals QUARK AND LEPTON MASS MATRICES WITH A4 FAMILY SYMMETRY

2007 ◽  
Vol 16 (05) ◽  
pp. 1383-1393 ◽  
Author(s):  
HIDEYUKI SAWANAKA
Keyword(s):  
Experimental Data ◽  
Neutrino Mixing ◽  
Family Symmetry ◽  
Mixing Angles ◽  
Quark Masses ◽  
Quark Sector ◽  
Mass Matrices ◽  
Mixing Matrix ◽  
Current Experimental Data

Realistic quark masses and mixing angles are obtained applying the successful A4 family symmetry for leptons, motivated by the quark-lepton assignments of SU (5). The A4 symmetry is suitable to give tri-bimaximal neutrino mixing matrix which is consistent with current experimental data. We study new scenario for the quark sector with the A4 symmetry.

NEUTRINO MASS AND MIXING: THE IMPACT OF EXCITED STATE CONTRIBUTIONS ON CAPTURE RATES OF Ga DETECTORS

1995 ◽  
Vol 10 (01) ◽  
pp. 133-143 ◽  
Author(s):  
KAMALES KAR ◽  
SRUBABATI GOSWAMI ◽  
AMITAVA RAYCHAUDHURI
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Absorption Cross ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Neutrino Mass And Mixing ◽  
Nuclear Models ◽  
The Impact ◽  
Neutrino Absorption ◽  
Capture Rates

In this paper we calculate the neutrino absorption cross-sections for the reaction 71Ga(ν, e−)71Ge using two simple nuclear models to account for the giant GT resonances. In both models the excited state contributions are found to have significant ranges of variation and affect the solar neutrino capture rates. Nonetheless, the regions in the neutrino mixing angle-mass squared difference plane allowed by the data from the Gallium detectors, when taken together with those from the Chlorine and Kamioka experiments, are found to be comparatively stable.

scholarly journals Model independent analysis of Dirac CP violating phase for some well-known mixing scenarios

2021 ◽  
pp. 2150188
Author(s):  
Sumit K. Garg
Keyword(s):  
Cp Violation ◽  
Numerical Investigation ◽  
Parameter Space ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Complex Rotation ◽  
Rotation Matrices ◽  
Independent Analysis ◽  
Model Independent ◽  
Pmns Matrix

In this paper, we present a model independent analysis of Leptonic CP violation for some well-known mixing scenarios. In particular, we considered modified schemes for bimaximal (BM), democratic (DC), hexagonal (HG) and tribimaximal (TBM) mixing for our numerical investigation. These model independent corrections to mixing matrices are parametrized in terms of complex rotation matrices [Formula: see text] with related modified PMNS matrix of the forms [Formula: see text] where [Formula: see text] is a complex rotation in [Formula: see text] sector and [Formula: see text] is unperturbed mixing scheme. We present generic formulae for mixing angles, Dirac CP phase [Formula: see text] and Jarlskog invariant [Formula: see text] in terms of correction parameters. The parameter space of each modified mixing case is scanned for fitting neutrino mixing angles using [Formula: see text] approach and the corresponding predictions for Leptonic CP phase [Formula: see text] and Jarlskog invariant [Formula: see text] has been evaluated from allowed parameter space. The obtained ranges are reported for all viable cases.

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.

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