Three-zero textures of neutrino mass matrix and leptogenesis in the left-right symmetric model

TL;DR

This paper analyzes three-zero textures of the neutrino mass matrix within the left-right symmetric model, identifying which textures fit experimental data and exploring their implications for leptogenesis and neutrino parameters.

Contribution

It systematically classifies viable three-zero textures of the Majorana neutrino mass matrix in LRSM and studies their impact on leptogenesis and neutrino phase correlations.

Findings

Only five textures satisfy experimental constraints.

Majorana CP phases are strongly constrained by textures.

Certain textures enable successful leptogenesis in specific mass orderings.

Abstract

Within the framework of the left-right symmetric model (LRSM) and under the assumption of a diagonal Dirac neutrino mass matrix $M_{\rm D}$, this paper systematically investigates 20 types of three-zero textures in the Majorana neutrino mass matrix $M_{\rm R}$. The study reveals that only five three-zero textures of $M_{\rm R}$ satisfy the constraints of the latest NuFit 6.0 global fit results. Furthermore, we phenomenologically explore the correlations between Majorana phases $\rho$ and $\sigma$, as well as the relationships between the heavy neutrino mass spectrum $M_{I}~(I=1,2,3)$, ratio of Dirac matrix elements $y_{2}$, $y_{3}$ and the scale factor $r$. The results indicate strong correlations among the model parameters. In particular, the allowed regions for the Majorana CP phases are significantly restricted and depend on the specific texture of $M_{\rm R}$. On this basis, leptogenesis originating from heavy right-handed neutrino decays is investigated. Numerical results demonstrate that the $M_{\nu3}$ pattern can achieve successful leptogenesis within specific $r$ intervals for both the normal ordering (NO) and the inverted ordering (IO) of the light neutrino masses, while the $M_{\nu4}$ and $M_{\nu5}$ patterns possess viable parameter space for successful leptogenesis only in the NO case.