Neutrino model with broken $\mu -\tau$ Symmetry and Unflavored Leptogenesis with Dihedral Flavor Symmetry

Abstract

We propose a new neutrino flavor model based on a $D_4\times U(1)$ flavor symmetry providing predictions for neutrino masses and mixing along with a successful generation of the observed Baryon Asymmetry of the Universe (BAU). After the spontaneous breaking of the flavor symmetry, the type I seesaw mechanism leads to a light neutrino mass matrix with broken $\mu -\tau$ symmetry. By performing a numerical analysis, we find that the model favors a normal mass hierarchy with the lightest neutrino mass lies in the range $m_1\in [2.516,21.351]$ m$\mathrm{eV}$. The phenomenological implications of the neutrino sector are explored in detail and the results are discussed. Moreover, the generation of BAU is addressed via the leptogenesis mechanism from the decay of three right-handed neutrinos $N_i$. Through analytical and numerical analysis of the baryon asymmetry parameter $Y_B$, a successful unflavored leptogenesis takes place within the allowed parameter space obtained from neutrino phenomenology. We also examine interesting correlations between $Y_B$ and low energy observables and provide a comprehensive discussion of the results.

Comments: 30 pages, 20 figures