Expected Properties of Massive Neutrinos for Mass Matrices with a Dominant Block and Random Coefficients Order Unity

Abstract

We study the class of neutrino mass matrices with a dominant block but unspecified O(1) coefficients, and scan the possible models by the help of random number generators. We discuss which are the most common expectations in dependence of the adjustable parameter of the mass matrices, "epsilon", and emphasise an interesting sub-class of models that have large mixing angles for atmospheric and solar neutrinos. For those models where the lepton mass matrices are subject to Froggatt-Nielsen U(1) selection rules, we show that the neutrino mixing matrix receives important contributions from the rotations operating on charged lepton sector, which increase the predicted value of the angle "theta(13)" and the ee-entry of the neutrino mass.