$\theta_{13}$, $\mu\tau$ symmetry breaking and neutrino Yukawa textures

TL;DR

This paper investigates how minimal $$ symmetry breaking in neutrino Yukawa textures within the type-I seesaw model can explain observed neutrino mixing angles, especially $ heta_{13}$, under inverted mass hierarchy.

Contribution

It introduces the most general lowest order $$ symmetry breaking perturbations to specific neutrino Yukawa textures and analyzes their compatibility with experimental data.

Findings

Small symmetry breaking parameters can fit current neutrino data.

Inverted mass hierarchy is compatible with observed mixing angles.

The model accommodates a $ heta_{13}$ in the observed range.

Abstract

Within the type-I seesaw and in the basis where charged lepton and heavy neutrino mass matrices are real and diagonal, $\mu\tau$ symmetric four and three zero neutrino Yukawa textures are perturbed by lowest order $\mu\tau$ symmetry breaking terms. These perturbations are taken to be the {\it most general ones for those textures}. For quite small values of those symmetry breaking parameters, permitting a lowest order analysis, current best-fit ranges of neutrino mass squared differences and mixing angles are shown to be accommodable, including a value of $\theta_{13}$ in the observed range, provided all the light neutrinos have an inverted mass ordering.