Compatibility of $A_{4}$ Flavour Symmetric Minimal Extended Seesaw with $(3+1)$ Neutrino Data

TL;DR

This paper investigates how an $A_4$ flavor symmetry integrated into a minimal extended seesaw model can produce viable $3+1$ neutrino mass textures consistent with recent oscillation data, favoring normal hierarchy.

Contribution

It introduces a classification of $3+1$ neutrino mass textures arising from $A_4$ symmetry and analyzes their compatibility with current experimental data.

Findings

Certain textures are compatible with data and predict correlations between neutrino parameters.

All allowed textures favor normal hierarchy over inverted hierarchy.

The study links $A_4$ vacuum alignments to specific neutrino mass matrix textures.

Abstract

Motivated by the recent resurrection of the evidence for an eV scale sterile neutrino from the MiniBooNE experiment, we revisit one of the most minimal seesaw model known as the minimal extended seesaw that gives rise to a $3+1$ light neutrino mass matrix. We consider the presence of $A_4$ flavour symmetry which plays a non-trivial role in generating the structure of the neutrino mass matrix. Considering a diagonal charged lepton mass matrix and generic vacuum alignments of $A_4$ triplet flavons, we classify the resulting mass matrices based on their textures. Keeping aside the disallowed texture zeros based on earlier studies of $3+1$ neutrino textures, we categorise the remaining ones based on texture zeros, $\mu-\tau$ symmetry in the $3\times3$ block and hybrid textures. After pointing out the origin of such $3+1$ neutrino textures to $A_4$ vacuum alignments, we use the latest $3+1$ neutrino oscillation data and numerically analyse the texture zeros and $\mu-\tau$ symmetric cases. We find that a few of them are allowed from each category predicting interesting correlations between neutrino parameters. We also find that all of these allowed cases prefer normal hierarchical pattern of light neutrino masses over inverted hierarchy.