Seesaw neutrino masses from an $A_4$ model with two equal vacuum expectation values

Abstract

We present a model for the lepton sector, with $A_4$ horizontal-symmetry group, in which two of the Higgs doublets in an $A_4$ triplet of Higgs doublets have equal vacuum expectation values. The model makes well-defined predictions for the effective light-neutrino Majorana mass matrix. We show that those predictions are compatible with the experimental data.

Comments: 22 pages, 8 figures; v2: added more complete analysis of LEP and Tevatron bounds