Hybrid Textures of Majorana Neutrino Mass Matrix and Current Experimental Tests

TL;DR

This paper systematically analyzes hybrid textures of Majorana neutrino mass matrices with one zero and two equal elements, testing their compatibility with experimental data and exploring their phenomenological implications.

Contribution

It identifies which hybrid textures are compatible with current neutrino data and demonstrates their stability and realization through flavor symmetries.

Findings

39 out of 60 patterns are compatible with data at 3σ

Texture zero is stable against quantum corrections

Implications for neutrinoless double-beta decay and CP violation

Abstract

Motivated by recent measurements of a relatively large \theta_{13} in the Daya Bay and RENO reactor neutrino experiments, we carry out a systematic analysis of the hybrid textures of Majorana neutrino mass matrix $M_\nu$, which contain one texture zero and two equal nonzero matrix elements. We show that three neutrino masses (m_1, m_2, m_3) and three leptonic CP-violating phases (\delta, \rho, \sigma) can fully be determined from two neutrino mass-squared differences (\delta m^2, \Delta m^2) and three flavor mixing angles (\theta_{12}, \theta_{23}, \theta_{13}). Out of sixty logically possible patterns of $M_\nu$, thirty-nine are found to be compatible with current experimental data at the 3\sigma level. We demonstrate that the texture zero of $M_\nu$ is stable against one-loop quantum corrections, while the equality between two independent elements not. Phenomenological implications of $M_\nu$ for the neutrinoless double-beta decay and leptonic CP violation are discussed, and a realization of the texture zero and equality by means of discrete flavor symmetries is illustrated.