Neutrino mass matrix in triplet Higgs models with A_4 symmetry

摘要

We consider triplet Higgs model with A_4 symmetry to generate the neutrino mass matrix. The tribimaximal form of the neutrino mixing matrix can be naturally obtained. Imposing the neutrino oscillation data, we show that 1) both normal and inverted mass hierarchy are allowed, 2) there is a lower bound on the lightest neutrino mass and the effective mass for neutrinoless double beta decay, 3) the non-vanishing θ_(13) can be accommodated by considering small perturbation, 4) θ_(atm) should be very close to π / 4 even after perturbation.