RGE-induced $\mu$-$\tau$ symmetry breaking: an analysis of the latest T2K results

Abstract

The T2K collaboration has recently reported their results, which gives the best-fit values of the atmospheric mixing angle $\sin^2 \theta_{23} = 0.53$ and the Dirac CP-violating phase $\delta = -1.89$ for normal neutrino mass ordering. We give a possible theoretical origin of such values based on the $\mu$-$\tau$ reflection symmetry. It has been found that the breaking of such symmetry using one-loop renormalization-group equations (RGEs) in the framework of minimal supersymmetric standard model can fit well with the latest T2K results and the recent global fits. To make a quantitative analysis, we have included for the first time the complete dataset of oscillation, beta decay, neutrinoless double-beta decay and cosmological observations in comparing the theory to experiments. We also further examine the importance of such breaking patterns for neutrinoless double-beta decay experiments.