Neutrino mass matrix in triplet Higgs models with $A_4$ symmetry

Understand

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 $\th_{13}$ can be accommodated by considering small perturbation, 4) $\th_{\rm atm}$ should be very close to $\pi/4$ even after perturbation.
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