Two-parameter neutrino mass matrices with two texture zeros

We reanalyse Majorana-neutrino mass matrices Mₙu with two texture zeros, by searching for viable hybrid textures in which the non-zero matrix elements of Mₙu 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 (Mₙu) ₌ₔ ₌ₔ: (Mnu) ₓ₀ₔ ₓ₀ₔ = 1: 1 and (Mₙu) ₄ ₓ₀ₔ: (Mnu) ₌ₔ ₓ₀ₔ = 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 m²₂1 and Delta m²₃1. We could not find viable hybrid textures based on mass matrices different from those of cases A1 and A2.