Mu-Tau Reflection Symmetry in the Standard Parametrization and Contributions from Charged Lepton Sector

TL;DR

This paper explores how mu-tau reflection symmetry can be made explicit in the standard parametrization of the PMNS matrix by considering maximal Majorana phases and charged lepton contributions, aligning with experimental data.

Contribution

It introduces a scheme to restore mu-tau reflection symmetry in the standard parametrization by incorporating maximal Majorana phases and charged lepton corrections.

Findings

Reflection symmetry can be restored with maximal Majorana phases.

Charged lepton contributions help accommodate non-maximal mixing angles.

Predictions are consistent with global neutrino oscillation data.

Abstract

The $\mu-\tau$ reflection symmetry of the lepton mixing matrix accommodates maximal atmospheric mixing ($\theta_{23}=\pi/4$) as well as maximal Dirac CP phase ($\delta=\pm \pi/2$) for the Dirac case. In the standard parametrization of the PMNS matrix the reflection symmetric nature is not directly visible while substituting the maximal values of the mixing parameters. This issue has been addressed in this paper. It is found that the reflection symmetry in the 'standard' PMNS matrix can be restored by allowing maximal values of the Majorana CP phases ($\alpha$, $\beta$) as well, along with maximal $\delta$. To accommodate non-maximal values of $\theta_{23}$ and $\delta$ we consider charged lepton contributions to the neutrino mixing and implement the proposed scheme of reflection symmetry in the neutrino mixing matrix. The charged lepton correction scheme succeeds in the prediction of lepton mixing parameters consistent with the global $3\nu$ oscillation data.