Neutrino mixing by modifying the Yukawa coupling structure of constrained sequential dominance

Joy Ganguly,Raghavendra Srikanth Hundi

doi:10.1103/physrevd.103.035007

Joy Ganguly, Raghavendra Srikanth Hundi

Open Access

https://doi.org/10.1103/physrevd.103.035007

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Abstract

In the constrained sequential dominance (CSD), tri-bimaximal mixing (TBM) pattern in the neutrino sector has been explained, by proposing a certain Yukawa coupling structure for the right-handed neutrinos of the model. However, from the current experimental data it is known that the values of neutrino mixing angles are deviated from the TBM values. In order to explain this neutrino mixing, we first propose a phenomenological model where we consider Yukawa couplings which are modified from that of CSD. Essentially, we add small complex parameters to the Yukawa couplings of CSD. Using these modified Yukawa couplings, we demonstrate that neutrino mixing angles can deviate from their TBM values. We also construct a model, based on a flavor symmetry, in order to justify the modified form of Yukawa couplings of our work.

Highlights

From various experimental observations it is known that neutrinos have very small mass [1]
The Yukawa couplings in Partially CSD (PCSD) can be obtained from that of our model by taking ε1 ≠ 0 and all other εi to be zero. With this Yukawa coupling structure, in the PCSD model, it is shown that sin θ13 ≠ 0 after assuming tri-bimaximal mixing (TBM) values for sin θ12 and sin θ23
These results are obtained in PCSD model up to a leading order in m2=m3

Summary

INTRODUCTION

From various experimental observations it is known that neutrinos have very small mass [1]. After assuming εi to be small, we study if we can consistently fit the neutrino masses and mixing angles, whose values are obtained from oscillation data. Using the analytic expressions for neutrino masses and mixing angles, in order to be compatible with current neutrino oscillation data, we present numerical results and demonstrate that the assumptions made in our diagonalization procedure are viable. In order to address this point, toward the end of this paper, we construct a model, based on symmetry groups, where we explain the smallness of εi parameters and justify the structure of Yukawa couplings of our phenomenological model. III, we describe our phenomenological model and explain the approximation procedure for diagonalizing the seesaw formula for neutrinos of this model Using this approximation procedure we demonstrate that the neutrino mixing angles in our model deviate away from the TBM pattern. In Appendix B, we analyze the scalar potential of our model in order to explain the hierarchy in the vevs of the scalar fields

SEQUENTIAL DOMINANCE AND CSD

OUR MODEL AND DEVIATIONS FROM TBM PATTERN

SECOND ORDER CORRECTIONS

NUMERICAL RESULTS

A MODEL FOR OUR DIRAC MASS MATRIX

CONCLUSIONS