Finite Modular Groups and Lepton Mixing

Understand

We study lepton mixing patterns which are derived from finite modular groups Gamma_N, requiring subgroups G_nu and G_e to be preserved in the neutrino and charged lepton sectors, respectively.

• We show that only six groups Gamma_N with N=3,4,5,7,8,16 are relevant.
• A comprehensive analysis is presented for G_e arbitrary and G_nu=Z2 x Z2, as demanded if neutrinos are Majorana particles.
• We discuss interesting patterns arising from both groups G_e and G_nu being arbitrary.