Discriminating Majorana Neutrino Textures in the light of Baryon Asymmetry

TL;DR

This paper systematically analyzes Majorana neutrino mass matrix textures with zeros, constraining them using neutrino oscillation, cosmology, and baryon asymmetry data within a type I seesaw framework.

Contribution

It provides a comprehensive study of texture zeros in Majorana neutrino matrices, linking them to baryon asymmetry constraints and CP phase predictions.

Findings

Identifies viable one-zero and two-zero textures consistent with data.

Constrains CP phases to produce correct baryon asymmetry.

Discriminates between neutrino mass hierarchies based on texture viability.

Abstract

We study all possible texture zeros in the Majorana neutrino mass matrix which are allowed from neutrino oscillation as well as cosmology data when the charged lepton mass matrix is assumed to take the diagonal form. In case of one-zero texture, we write down the Majorana phases which are assumed to be equal and the lightest neutrino mass as a function of the Dirac CP phase. In case of two-zero texture, we numerically evaluate all the three CP phases and lightest neutrino mass by solving four real constraint equations. We then constrain texture zero mass matrices from the requirement of producing correct baryon asymmetry through the mechanism of leptogenesis. Adopting a type I seesaw framework, we consider the CP violating out of equilibrium decay of the lightest right handed neutrino as the source of lepton asymmetry. Apart from discriminating between the texture zero mass matrices and light neutrino mass hierarchy, we also constrain the Dirac and Majorana CP phases so that the observed baryon asymmetry can be produced. In two-zero texture, we further constrain the diagonal form of Dirac neutrino mass matrix from the requirement of producing correct baryon asymmetry.