Majorana phase in minimal S-3 invariant extension of the standard model

摘要

The leptonic sector in a recently proposed minimal extension of the standard model, in which the permutation symmetry S-3 is assumed to be an exact flavor symmetry at the weak scale, is revisited. We find that S-3 with an additional Z(N) symmetry allows one CP violating phase phi(nu) in the neutrino mixing. The leptonic sector contains six real parameters besides the phase phi(nu) to describe charged lepton and neutrino masses and the neutrino mixing. The model predicts: an inverted spectrum of neutrino mass, the absence of CP violating Dirac phase, tantheta(23) = 1 + 0(m(e)(2)/m(mu)(2)) and sintheta(13) = 0.0034 + O(m(e)m(mu)/m(tau)(2)). Neutrino mass as well as the effective Majorana mass in the neutrinoless double-beta decay can be expressed in a closed form as a function of phi(nu), Deltam(23)(2) and tantheta(12). The model also predicts greater than or equal to (0.036-0.066) eV. (C) 2003 Elsevier B.V. All rights reserved. [References: 70]