$ \mu-\tau $ Reflection Symmetry and Its Explicit Breaking for Leptogenesis in a Minimal Seesaw Model

TL;DR

This paper explores a minimal seesaw model with $- au$ reflection symmetry, analyzing its implications for neutrino oscillation parameters and baryon asymmetry, and how explicit symmetry breaking can account for observed universe asymmetry.

Contribution

It introduces a minimal seesaw framework with specific predictive mass matrices obeying $- au$ reflection symmetry and studies its phenomenological implications for neutrino mixing and leptogenesis.

Findings

Predicts $ heta_{23} = /4$ and $ = /2$ for CP phase.

Perturbation of order 10^{-2} explains observed BAU.

Broken symmetry correlates neutrino parameters with baryon asymmetry.

Abstract

The minimal seesaw framework, embroiling the Dirac neutrino mass matrix $ M_D $ and the Majorana neutrino mass matrix $ M_R $, is quite successful to explain the current global-fit results of neutrino oscillation data. In this context, we consider most predictive forms of $ M_D $ and $ M_R $ with two simple parameters, respectively. Considering these matrices, we obtain the low energy neutrino mass matrix under type-I seesaw formalism which obeys $ \mu-\tau $ reflection symmetry and predicts $ \theta_{23} = \pi/4$ and $ \delta = \pm \pi/2 $. In the given set-up, we also evaluate the Baryon Asymmetry of the Universe (BAU) through successful leptogenesis and find that perturbation of $ \mathcal{O}(10^{-2}) $ leads to the observed BAU and breaks exactness of the symmetry. Moreover, we also perform various correlation studies among different parameters in the framework of broken symmetry.