Non-zero $\theta_{13}$ and CP violation in a model with $A_4$ flavor symmetry

TL;DR

This paper presents a neutrino model with $A_4$ symmetry explaining non-zero $ heta_{13}$ and CP violation, aligning with recent experimental data and incorporating radiative mass generation.

Contribution

It introduces a renormalizable $A_4$ symmetric neutrino model that accounts for deviations from tri-bimaximal mixing and links CP violation to Yukawa coupling non-degeneracy.

Findings

Model successfully fits current neutrino oscillation data.

Deviations from TBM arise from non-degenerate Yukawa couplings.

CP phases in Yukawa matrix lead to observable CP violation.

Abstract

Motivated by recent observations of non-zero $\theta_{13}$ from the Daya Bay and RENO experiments, we propose a renormalizable neutrino model with $A_4$ discrete symmetry accounting for deviations from the tri-bimaximal mixing pattern of neutrino mixing matrix indicated by neutrino oscillation data. In the model, the light neutrino masses can be generated by radiative corrections, and we show how the light neutrino mass matrix can be diagonalized by the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix whose entries are determined by the current neutrino data including the Daya Bay result. We show that the origin of the deviations from the TBM mixing is non-degeneracy of the neutrino Yukawa coupling constants, and unremovable CP phases in the neutrino Yukawa matrix give rise to both low energy CP violation measurable from neutrino oscillation and high energy CP violation.