The little flavons

Abstract

Fermion masses and mixing matrices can be described in terms of spontaneously broken (global or gauge) flavor symmetries. We propose a little-Higgs inspired scenario in which an SU(2)xU(1) gauge flavor symmetry is spontaneously (and completely) broken by the vacuum of the dynamically induced potential for two scalar doublets (the flavons) which are pseudo-Goldstone bosons remaining after the spontaneous breaking--at a scale between 10 and 100 TeV--of an approximate SU(6) global symmetry. The vacuum expectation values of the flavons give rise to the texture in the fermion mass matrices. We discuss in detail the case of leptons. Light-neutrino masses arise by means of a see-saw-like mechanism that takes place at the same scale at which the SU(6) global symmetry is broken. We show that without any fine tuning of the parameters the experimental values of the charged-lepton masses,the neutrino square mass differences and the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix are reproduced.