Neutrino mixing and leptogenesis in $\mu -\tau$ symmetry

We study the consequences of the $Z_2$ symmetry behind the $\mu$-$\tau$ universality in the neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass hierarchies and generate enough lepton asymmetry to interpret the observed baryon asymmetry in the universe. We also show how a specific form of a high-scale perturbation is kept when translated via the seesaw into the low scale domain, where it can accommodate the neutrino mixing data. We finally present a realization of the high scale perturbed texture through the addition of matter and extra exact symmetries.

Figure 1

The correlations of $⟨m{⟩}_{ee}$ against $\theta$, $\delta$, $|\chi |$, and $J$ are depicted in the first four rows, whereas the last two rows are reserved for the correlations of mass ratios $m_{23}$ and $m_{21}$ against $m_3$.