$A_4$ realization of Linear Seesaw and Neutrino Phenomenology

TL;DR

This paper develops an $A_4$ flavor symmetry-based linear seesaw model to explain neutrino oscillation data, CP violation, and baryon asymmetry, while analyzing its phenomenological implications and experimental testability.

Contribution

It introduces an $A_4$ flavor symmetry realization of the linear seesaw with extended particle content and symmetries, exploring its compatibility with recent neutrino data and leptogenesis.

Findings

Model can accommodate neutrino oscillation parameters

Non-unitarity effects are found to be small

Potential to explain baryon asymmetry via leptogenesis

Abstract

Motivated by the crucial role played by the discrete flavour symmetry groups in explaining the observed neutrino oscillation data, we consider the $A_4$ realization of linear seesaw by extending the standard model (SM) particle content with two types of right-handed neutrinos along with the flavon fields, and the SM symmetry with $A_4\times Z_4\times Z_2$ and a global symmetry $U(1)_X$ which is broken explicitly by the Higgs potential. We scrutinize whether this model can explain the recent results from neutrino oscillation experiments by searching for parameter space that can accommodate the observables such as the reactor mixing angle $\theta_{13}$, the CP violating phase $\delta_{CP}$, sum of active neutrino masses $\Sigma_{i} m_i$, solar and atmospheric mass squared differences, and the lepton number violating parameter called as effective Majorana mass parameter, in line with recent experimental results. We also discuss the scope of this model to explain the baryon asymmetry of the universe through Leptogenesis. We also investigate the possibility of probing the non-unitarity effect in this scenario, but it is found to be rather small.