Two A5 modular symmetries for Golden Ratio 2 mixing

Abstract

We present a model of leptonic mixing based on two A5 modular symmetries using the Weinberg operator. The two modular symmetries are broken to the respective diagonal A5 subgroup. At the effective level, the model behaves as a model with a single A5 modular flavour symmetry, but with two moduli. Using both as stabilisers, different residual symmetries are preserved, leading to Golden Ratio mixing that is perturbed by a rotation.