Neutrino mixing and masses in a left-right model with mirror fermions

TL;DR

This paper explores neutrino masses and lepton flavor violation within a left-right symmetric model with mirror fermions, showing consistency with experimental bounds and proposing a specific neutrino mixing structure.

Contribution

It introduces a comprehensive analysis of neutrino masses, decay rates, and flavor violation in a left-right mirror fermion model, including a novel parameterization leading to Tri-bimaximal mixing.

Findings

Neutrino masses are consistent with experimental bounds.

Upper limits on lepton flavor violating decay branching ratios are established.

Heavy Majorana neutrino decay rates are roughly equal for large masses.

Abstract

In the framework of a left-right model containing mirror fermions with gauge group SU(3)$_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}$, we estimate the neutrino masses, which are found to be consistent with their experimental bounds and hierarchy. We evaluate the decay rates of the Lepton Flavor Violation (LFV) processes $\mu \rightarrow e \gamma$, $\tau \rightarrow \mu \gamma$ and $\tau \rightarrow e\gamma$. We obtain upper limits for the flavor-changing branching ratios in agreement with their present experimental bounds. We also estimate the decay rates of heavy Majorana neutrinos in the channels $N \rightarrow W^{\pm} l^{\mp}$, $N \rightarrow Z \nu_{l}$ and $N \rightarrow H \nu_{l}$, which are roughly equal for large values of the heavy neutrino mass. Starting from the most general Majorana neutrino mass matrix, the smallness of active neutrino masses turns out from the interplay of the hierarchy of the involved scales and the double application of seesaw mechanism. An appropriate parameterization on the structure of the neutrino mass matrix imposing a symmetric mixing of electron neutrino with muon and tau neutrinos leads to Tri-bimaximal mixing matrix for light neutrinos.