Topic: Modular symmetry at level 6 and a new route towards finite modular groups

Speaker: Prof. Caichang Li

Coordinates:  PCFT C1124, 16:00, Thursday, Mar. 3

Abstract: We propose to construct the finite modular groups from the quotient of two principal congruence subgroups as G(N')/G(N''), and the modular group SL(2,Z) is extended to a principal congruence subgroup G(N'). The original modular invariant theory is reproduced when N'=1. We perform a comprehensive study of G6' modular symmetry corresponding to N'=1 and N''=6, five types of models for lepton masses and mixing with G6' modular symmetry are discussed and some example models are studied numerically. The case of N'=2 and N''=6 is considered, the finite modular group is G(2)/G(6)≌T', and a benchmark model is constructed.