Consequences of $\mu$-$\tau$ reflection symmetry for $3+1$ neutrino mixing

Abstract

We investigate the consequences of $\mu -\tau$ reflection symmetry in presence of a light sterile neutrino for the $3+1$ neutrino mixing scheme. We discuss the implications of total $\mu -\tau$ reflection symmetry as well partial $\mu -\tau$ reflection symmetry. For the total $\mu -\tau$ reflection symmetry we find values of ${\theta }_{23}$ and $\delta$ remains confined near $\pi /4$ and $\pm \pi /2$ respectively. The current allowed region for ${\theta }_{23}$ and $\delta$ in case of inverted hierarchy lies outside the area preferred by the total $\mu -\tau$ reflection symmetry. However, interesting predictions on the neutrino mixing angles and Dirac CP violating phases are obtained considering partial $\mu -\tau$ reflection symmetry. We obtain predictive correlations between the neutrino mixing angle ${\theta }_{23}$ and Dirac CP phase $\delta$ and study the testability of these correlations at the future long baseline experiment DUNE. We find that while the imposition of $\mu -\tau$ reflection symmetry in the first column admit both normal and inverted neutrino mass hierarchy, demanding $\mu -\tau$ reflection symmetry for the second column excludes the inverted hierarchy. Interestingly, the sterile mixing angle ${\theta }_{34}$ gets tightly constrained considering the $\mu -\tau$ reflection symmetry in the fourth column. We also study consequences of $\mu -\tau$ reflection symmetry for the Majorana phases and neutrinoless double beta decay.

Comments: 8 figures, Version accepted in PRD