Sterile Neutrino in Minimal Extended Seesaw with $A_{4}$ Flavour Symmetry

Abstract

In this work, we first review the status of evidences in support of existence of sterile neutrinos. Then, after revisiting one of the most minimal seesaw (MES) model that gives rise to a ($3+1$) light neutrino mass matrix, we include $A_4$ flavour symmetry in the theory. Considering the generic vacuum alignments of $A_4$ triplet flavons, we classify the resulting mass matrices based on their textures, and predict interesting correlations between neutrino oscillation in the allowed cases. We also find that all of these allowed cases prefer normal hierarchical pattern of light neutrino masses over inverted hierarchy.