Two A4 modular symmetries for Tri-Maximal 2 mixing

Abstract

We construct a lepton flavour model based on two A4 modular symmetries. The two A4 are broken by a bi-triplet field to the diagonal A4 subgroup, resulting in an effective modular A4 flavour symmetry with two moduli. We employ these moduli as stabilisers, that preserve distinct residual symmetries, enabling us to obtain Tri-Maximal 2 (TM2) mixing with a minimal field content, flavonless at the effective scale, below the breaking to the single A4.