Two-parameter neutrino mass matrices with two texture zeros

TL;DR

This paper reanalyzes Majorana neutrino mass matrices with two texture zeros, identifying specific viable hybrid textures with simple ratios that align well with experimental neutrino mixing data.

Contribution

It introduces new viable hybrid textures for neutrino mass matrices with specific ratio patterns, expanding the classification of neutrino mass models.

Findings

Identifies hybrid textures A1 and A2 with simple ratio patterns.

Shows these textures fit experimental neutrino mixing angles.

No other viable hybrid textures found beyond A1 and A2.

Abstract

We reanalyse Majorana-neutrino mass matrices M_nu with two texture zeros, by searching for viable hybrid textures in which the non-zero matrix elements of M_nu have simple ratios. Referring to the classification scheme of Frampton, Glashow and Marfatia, we find that the mass matrix denoted by A1 allows the ratios (M_nu)_{mu mu} : (Mnu)_{tau tau} = 1:1 and (M_nu)_{e tau} : (Mnu)_{mu tau} = 1:2. There are analogous ratios for texture A2. With these two hybrid textures, one obtains, for instance, good agreement with the data if one computes the three mixing angles in terms of the experimentally determined mass-squared differences Delta m^2_21 and Delta m^2_31. We could not find viable hybrid textures based on mass matrices different from those of cases A1 and A2.