Nonzero $\theta_{13}$ and Leptogenesis in a Type-I See-saw Model with $A_4$ Symmetry

TL;DR

This paper extends an $A_4$ flavor symmetry model with an extra flavon to account for the observed nonzero $ heta_{13}$ in neutrino mixing, linking it to leptogenesis within a type-I see-saw framework.

Contribution

It introduces a new flavon to the $A_4$ model, producing a nonzero $ heta_{13}$ and connecting neutrino mixing with leptogenesis, including sum rules and phase constraints.

Findings

Nonzero $ heta_{13}$ achieved at leading order.

Leptogenesis can occur with next-to-leading order Yukawa couplings.

Majorana phases influence CP asymmetry and $ heta_{13}$ involvement.

Abstract

In the light of recent discovery of nonzero $\theta_{13}$, we have analyzed the Altarelli-Feruglio $A_4$ flavor symmetry model extended with additional flavon. The inclusion of the new field leads to the deviation from exact tri-bimaximal neutrino mixing pattern in the context of type-I see-saw by producing a nonzero $\theta_{13}$ consistent with the recent experimental results at the leading order. A sum rule for light neutrino masses is also obtained in this context. The set-up constraints the two Majorana phases involved in the lepton mixing matrix in terms of $A_4$ parameter space. We have shown that a nonzero lepton asymmetry can be generated while next-to-leading order contributions to the neutrino Yukawa couplings are considered. The two Majorana phases play crucial role in CP-asymmetry parameter and the involvement of $\theta_{13}$ in it, is exercised.