Neutrino Mixing with Non-Zero $\theta_{13}$ and CP Violation in the 3-3-1 Model Based on $S_4$ Flavor Symmetry

TL;DR

This paper updates a 3-3-1 model with $S_4$ symmetry to naturally incorporate non-zero $ heta_{13}$ and CP violation in neutrino mixing, reducing Higgs multiplets and aligning with recent oscillation data.

Contribution

It introduces a new $SU(3)_L$ anti-sextet in the $S_4$-based 3-3-1 model to generate non-zero $ heta_{13}$ without perturbation, simplifying the Higgs sector and matching experimental neutrino data.

Findings

Neutrino masses and mixings are consistent with latest oscillation data.

Predicted Dirac CP phase: 292.45° (normal) and 303.14° (inverted).

Upper bounds on neutrino mass and neutrinoless double beta decay effective mass.

Abstract

The 3-3-1 model proposed in 2011 based on discrete symmetry $S_4$ responsible for the neutrino and quark masses is updated, in which the non-zero $\theta_{13}$ is focused. Neutrino masses and mixings are consistent with the most recent data on neutrino oscillations without perturbation. The new feature is adding a new $SU(3)_L$ anti-sextet lying in doublet under $S_4$ which can result the non-zero $\theta_{13}$ without perturbation, and consequently, the number of Higgs multiplets required is less than those of other models based on non-Abelian discrete symmetries and the 3-3-1 models. The exact tribimaximal form obtained with the breaking $S_4 \rightarrow Z_3$ in charged lepton sector and $S_4 \rightarrow \mathcal{K}$ in neutrino sector. If both breakings $S_4\rightarrow \mathcal{K}$ and $\mathcal{K} \rightarrow Z_2$ are taken place in neutrino sector, the realistic neutrino spectrum is obtained without perturbation. The upper bound on neutrino mass and the effective mass governing neutrinoless double beta decay at the tree level are presented. The model predicts the Dirac CP violation phase $\delta=292.45^\circ$ in the normal spectrum (with $\theta_{23}\neq \frac{\pi}{4}$) and $\delta=303.14^\circ$ in the inverted spectrum.