A minimal modular invariant neutrino model

Abstract

We present a neutrino mass model based on modular symmetry with the fewest input parameters to date, which successfully accounts for the 12 lepton masses and mixing parameters through 6 real free parameters including the modulus. The neutrino masses are predicted to be normal ordering, the atmospheric angle $\theta_{23}$ is quite close to maximal value and the Dirac CP phase $\delta_{CP}$ is about $1.34\pi$. We also study the soft supersymmetry breaking terms due to the modulus $F$-term in this minimal model, which are constrained to be the non-holomorphic modular forms. The radiative lepton flavor violation process $\mu\to e\gamma$ is discussed.