Low-energy phenomena of the lepton sector in an A₄ symmetry model with heavy inverse seesaw neutrinos

An extension of the two Higgs doublet model including inverse seesaw neutrinos and neutral Higgs bosons was constructed based on the A₄ symmetry in order to explain the recent neutrino oscillation data. This model can distinguish two well-known normal and inverted order schemes of neutrino data once both the effective masses m_β in tritium beta decays and 〈m〉 in the neutrinoless double beta decay are observed. The lepton flavor violating decays of the charged leptons e_b → e_aγ, μ → 3e, the Standard Model-like Higgs boson decays h → e_be_a, and the μ-e conversions in some nuclei are generated from loop corrections. The experimental data on the branching ratio Br(μ → eγ, 3e) predict that the upper bounds of Br(τ → μγ, eγ) and Br(h → e_ae_b) are much smaller than the planned experimental sensitivities. In contrast, the μ-e conversions are promising signals for experiments.