Type II seesaw models with modular A4 symmetry

Abstract

We discuss type II seesaw models adopting modular A4 symmetry in a supersymmetric framework. In our approach, the models are classified by the assignment of A4 representations and modular weights for leptons and triplet Higgs fields. Then neutrino mass matrix is characterized by modulus τ and two free parameters. Carrying out numerical analysis, we find allowed parameter sets which can fit the neutrino oscillation data. For the allowed parameter sets, we obtain the predictions in the neutrino sector such as CP violating phases and the lightest neutrino mass. Finally, we also show the predictions for the branching ratios of a doubly charged scalar boson, focusing on the case where the doubly charged scalar boson dominantly decays into charged leptons.