The flavor problem and discrete symmetries

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In this Letter we propose a multi-Higgs extension of the standard model with Abelian and non-Abelian discrete symmetries in which the mass matrices of the charged fermions obtained from renormalizable interactions are diagonal. However, non-diagonal contributions, that are important for obtaining the CKM matrix in the quark sector, arise from non-renormalizable dimension five interactions. Active neutrinos acquire mass only from non-renormalizable interactions, the non-diagonal entries arising through dimension five operators, while the diagonal entries comes from dimension six operators. Realistic mixing matrices in the neutrino and the quarks sectors are obtained. (C) 2009 Elsevier B.V. All rights reserved.