Simplest Neutrino Mixing from S4 Symmetry

TL;DR

This paper presents a model based on S4 symmetry that naturally produces the 'Simplest' neutrino mass matrix, accurately predicting the reactor mixing angle and CP violation, consistent with current data and testable in future experiments.

Contribution

It introduces a specific S4 symmetry-based model that derives the 'Simplest' neutrino texture within the type-1 see-saw framework, linking neutrino masses to mixing parameters.

Findings

Predicted sin^2(theta13) ~ 0.086, matching experimental values.

Model predicts large CP asymmetries.

Predictions are testable with future neutrino experiments.

Abstract

In 2004, two of us proposed a texture, the "Simplest" neutrino mass matrix, which predicted sin(theta13)=sqrt((2 Solar-Delta m^2)/(3 Atm-Delta m^2)) and delta_CP=90 degrees. Using today's measured values for neutrino mass-squared differences, this prediction gives sin^2(theta13)~0.086+0.003-0.006, compared with a measured value, found by averaging the results of the Daya Bay and RENO experiments, of sin^2(theta13)=0.093+0.010-0.010. Here we present a specific model based on S4 symmetry leading to this successful texture in the context of the type-1 see-saw mechanism, assuming Majorana neutrinos. In this case, slightly different predictions are obtained relating theta13 to the light neutrino masses, which are in accord with current experimental limits and testable at future experiments. Large CP asymmetries remain a generic prediction of the texture.