New lepton family symmetry and neutrino tribimaximal mixing

The newly proposed finite symmetry Sigma(81) is applied to the problem of neutrino tribimaximal mixing. The result is more satisfactory than those of previous models based on A(4) in that the use of auxiliary symmetries ( or mechanisms) may be avoided. Deviations from the tribimaximal pattern are expected, but because of its basic structure, only tan(2)theta(12) may differ significantly from 0.5 (say 0.45) with sin(2)2 theta(23) remaining very close to unity, and theta(13) very nearly zero. Copyright (C) EPLA, 2007.