The reactor mixing angle and CP violation with two texture zeros in the light of T2K

TL;DR

This paper analyzes how two texture zeros in symmetric neutrino mass matrices relate to recent T2K results, predicting reactor mixing angles and CP violation phases, and identifying which models align with experimental data.

Contribution

It revisits neutrino mass matrix textures in light of new T2K and global analysis data, identifying viable cases and their predictions for mixing angles and CP violation.

Findings

Cases A1 and A2 predict non-zero reactor angle within specific ranges.

Only A1 and A2 are compatible with a normal mass hierarchy.

Certain cases predict nearly maximal CP violation.

Abstract

We reconsider the phenomenological implications of two texture zeros in symmetric neutrino mass matrices in the light of the recent T2K result for the reactor angle and the new global analysis which gives also best fit values for the Dirac CP phase delta. The most important results of the analysis are: Among the viable cases classified by Frampton et al. only A1 and A2 predict the reactor mixing angle to be different from zero at 3 sigma. Furthermore these two cases are compatible only with a normal mass spectrum in the allowed region for the reactor angle. At the best fit value A1 and A2 predict 0.024 >= sin^2(theta13) >= 0.012 and 0.014 <= sin^2(theta13) <= 0.032, respectively, where the bounds on the right and the left correspond to cos(delta)=-1 and cos(delta)=1, respectively. The cases B1, B2, B3 and B4 predict nearly maximal CP violation, i.e. cos(delta) is approximately zero.