Dirac neutrino mixings from hidden $\mu-\tau$ symmetry

TL;DR

This paper investigates how a hidden $-$ symmetry influences Dirac neutrino masses and mixings, analyzing the parameter space consistent with current experimental data and estimating the Higgs invisible decay rate into neutrinos.

Contribution

It introduces a general parameterization of Dirac neutrino mass matrices with hidden $-$ symmetry and explores the symmetry breaking scale using experimental data.

Findings

Symmetry breaking is in the range of the atmospheric mass scale.

The model accommodates current neutrino oscillation data.

Estimated Higgs decay into neutrinos aligns with recent measurements.

Abstract

We explore masses and mixings for Dirac neutrinos in models where lepton number is conserved, under the guidance of a hidden, but broken, $\mu-\tau$ exchange symmetry, that makes itself evident in the squared hermitian mass matrix. We study the parameter space in the most general theory as allowed by current neutrino oscillation experiment data. By using a general parameterization of the mass matrix which contains only observable parameters we stablish that the amount of breaking of the symmetry is in the range of the atmospheric mass scale, without regard to the neutrino hierarchy, the absolute neutrino mass and the Dirac CP phase. An estimate of the invisible branching ratio for a Higgs boson decaying into Dirac neutrinos, $H\rightarrow\nu\overline{\nu}$ , is given and compared to recent measurements in this context.