scholarly journals RENORMALIZATION OF THE NEUTRINO MASS MATRIX

2002 ◽  
Vol 17 (36) ◽  
pp. 2355-2360 ◽  
Author(s):  
T. K. KUO
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Analytic Solutions ◽  
Neutrino Mass Matrix ◽  
Mass Hierarchy ◽  
Mixing Angle ◽  
Resonance Behavior ◽  
Infinite Mass ◽  
Exact Analytic Solutions ◽  
Physical Mixing

The renormalization group equations for the general 2 × 2, complex, neutrino mass matrix are shown to have exact, analytic solutions. Simple formulas are given for the physical mixing angle, mass ratio and intrinsic CP phase. We also establish a (complex) renormalization invariant relating these parameters. It is found that the mixing angle exhibits the resonance behavior. Also, the infrared fixed point corresponds to vanishing mixing angle and infinite mass hierarchy.

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 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.

scholarly journals On resolving the dark LMA solution at neutrino oscillation experiments

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Sandhya Choubey ◽  
Dipyaman Pramanik
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Double Beta Decay ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Long Baseline ◽  
Combine Information ◽  
Oscillation Experiment

Abstract In presence of non standard interactions (NSI), the solar neutrino data is consistent with two solutions, one close to the standard LMA solution with sin2θ12 ≃ 0.31 and another with $$ {\sin}^2{\theta}_{12}^D\simeq 0.69\left(=1-{\sin}^2{\theta}_{12}\right) $$ sin 2 θ 12 D ≃ 0.69 = 1 − sin 2 θ 12 . The latter has been called the Dark LMA (DLMA) solution in the literature and essentially brings an octant degeneracy in the measurement of the mixing angle θ12. This θ12 octant degeneracy is hard to resolve via oscillations because of the existence of the so-called “generalised mass hierarchy degeneracy” of the neutrino mass matrix in presence of NSI. One might think that if the mass hierarchy is independently determined in a non-oscillation experiment such as neutrino-less double beta decay, one might be able to break the θ12 octant degeneracy. In this paper we study this in detail in the context of long-baseline experiments (Pμμ channel) as well as reactor experiments (Pee channel) and show that if we combine information from both long-baseline and reactor experiments we can find the correct octant and hence value of θ12. We elaborate the reasons for it and study the prospects of determining the θ12 octant using T2HK, DUNE and JUNO experiments. Of course, one would need information on the neutrino mass hierarchy as well.

scholarly journals What if θ13 is small?

2006 ◽  
Vol 84 (6-7) ◽  
pp. 621-623
Author(s):  
C S Lam
Keyword(s):  
Mass Spectrum ◽  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Inverted Hierarchy ◽  
Seesaw Mechanism ◽  
Mixing Angle ◽  
Left Handed ◽  
The Right

In the basis where the charged lepton mass matrix is diagonal, the left-handed neutrino mass matrix is invariant under the permutation of the second and third generations if, and only if, the reactor angle θ13 is zero and the atmospheric mixing angle θ23 is maximal. In the presence of the seesaw mechanism, this symmetry leads to an inverted hierarchy, with m3 = 0. This inverted mass spectrum is doubly protected if the right-handed neutrinos also have a 2–3 symmetry.PACS No.: 14.60Pq

scholarly journals PHENOMENOLOGY OF "BIMAXIMAL + DEMOCRATIC" TYPE NEUTRINO MASS MATRIX

2006 ◽  
Vol 21 (13) ◽  
pp. 1067-1073 ◽  
Author(s):  
AMBAR GHOSAL ◽  
DEBASISH MAJUMDAR
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mass Matrix ◽  
Experimental Results ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Mixing Angles ◽  
The Masses

We demonstrate that "Bimaximal + Democratic" type neutrino mass matrix can accommodate the deviation of θ⊙ from its maximal value along with the other present-day neutrino experimental results, namely, atmospheric, CHOOZ, neutrinoless double beta decay (ββ0ν) and result obtained from WMAP experiment. We define a function χp in terms of solar and atmospheric neutrino mass squared differences and solar neutrino mixing angle (obtained from different experiments and our proposed texture). The masses and mixing angles are expressed in terms of three parameters in our proposed texture. The allowed region of the texture parameters is obtained through minimization of the above function. The proposed texture crucially depends on the value of the experimental results of ββ0ν experiment among all other above-mentioned experiments. If, in future, ββ0ν experiments, namely, MOON, EXO, GENIUS shift the lower bound on 〈mee〉 at the higher side by one order, the present texture will be ruled out.

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