題目:
Modular flavor symmetries and CP from the string theory
Abstract:
First, we discuss the recent development of flavor symmetries and CP in the string theory.
The flavor symmetry is a powerful approach to understand the flavor structure of quarks and leptons,
and in addition, it provides the bridge between bottom-up and top-down approaches of model building.
As discussed in my talk, the flavor symmetry will be embedded into a geometric symmetry of an extra-dimensional space,
and subgroups of the geometric symmetry would control the flavor structure of matter zero-modes.
Second, we discuss the minimal flavor violation in the context of string effective field theory.
Stringy selection rules indicate that n-point couplings among fermionic zero-modes and lightest scalar modes in the string effective action are given by a product of Yukawa couplings which are regarded as spurion fields of stringy and geometrical symmetries. Hence, Yukawa couplings determine the dynamics of flavor and CP violations. This observation strongly supports the hypothesis of minimal flavor violation in the Standard Model effective field theory.
