Revisiting Trimaximal TM2 mixing in two $A_4$ modular symmetries

Abstract

We discuss a minimal lepton flavour model with two modular $A_4$ symmetries, one acting on neutrinos and the other acting on charged leptons. Two corresponding moduli fields are restricted at stabilisers. To avoid vanishing or degenerate lepton masses, the stabiliser in the charged lepton sector always preserves a $Z_3$ symmetry, and that in the neutrino preserves a $Z_2$ symmetry. By scanning all viable stabilisers, a unique Trimaximal TM2 mixing is predicted. However, the prediction of the lightest neutrino mass and the mass parameter in neutrinoless double beta decay, as well as two Majorana phases, are different and classified into three cases.

Comments: 24 pages, 2 figures, 4 tables, refs and comments added, accepted for publication in IJMPA