Non-zero $\theta_{13}$ from the Triangular Ansatz and Leptogenesis

TL;DR

This paper explores how a triangular Dirac neutrino mass matrix, with slight deviations from symmetry, can produce the observed non-zero neutrino mixing angle $ heta_{13}$ and account for the universe's baryon asymmetry through leptogenesis.

Contribution

It reconstructs a triangular Dirac neutrino mass matrix incorporating deviations from $ au- ext{symmetry}$ to explain $ heta_{13}$ and demonstrates its viability for leptogenesis.

Findings

Non-zero $ heta_{13}$ is achieved through specific parameters in the triangular mass matrix.

The triangular texture can generate the observed baryon asymmetry via leptogenesis.

Deviations from $ au- ext{symmetry}$ are parametrized by dimensionless parameters $y_i$.

Abstract

Recent experiments indicate a departure from the exact Tri-Bimaximal mixing by measuring definitive non-zero value of $\theta_{13}$. Within the framework of type I seesaw mechanism, we reconstruct the triangular Dirac neutrino mass matrix from the $\mu-\tau$ symmetric mass matrix. The deviation from $\mu-\tau$ symmetry is then parametrized by adding dimensionless parameters $y_i$ in the triangular mass matrix. In this parametrization of the neutrino mass matrix, the non-zero value $\theta_{13}$ is controlled by $\Delta y = y_4 - y_6$. We also calculate the resulting leptogenesis and show that the triangular texture can generate the observed baryon asymmetry in the universe via leptogenesis scenario.