Quasi-Dirac neutrinos in a model with local $B-L$ symmetry

TL;DR

This paper explores a model with local $B-L$ symmetry and exotic charge assignments for right-handed neutrinos, demonstrating how a quasi-Dirac neutrino scheme can naturally emerge and align with experimental data on neutrino mixing angles.

Contribution

It introduces a novel $B-L$ symmetry model with unique charge assignments and $S_3$ symmetry, showing how to achieve realistic neutrino mixing angles.

Findings

Quasi-Dirac neutrino scheme arises naturally in the model.

The model can produce a $ heta_{13}$ angle consistent with Daya Bay results.

Breaking $S_3$ symmetry in charged lepton interactions is necessary.

Abstract

In a model with $B-L$ gauge symmetry, right-handed neutrinos may have exotic local $B-L$ charge assignment: two of them with $B-L=-4$ and the other one having $B-L=5$. Then, it is natural to accommodate the right-handed neutrinos with the same $B-L$ charge in a doublet of the discrete $S_3$ symmetry, and the third one in a singlet. If the Yukawa interactions involving right-handed neutrinos are invariant under $S_3$, the quasi-Dirac neutrino scheme arise naturally in this model. However, we will show how in this scheme it is possible to give a value for $\theta_{13}$ in agreement with the Daya Bay results. For example the $S_3$ symmetry has to be broken in the Yukawa interactions involving right-handed charged lepton.