Flavor and CP from String Theory

TL;DR

This paper explores how modular transformations in string theory unify CP and flavor symmetries, leading to a framework where different sectors of the Standard Model can have distinct flavor structures due to local flavor unification.

Contribution

It introduces the concept of eclectic flavor scheme where modular transformations unify CP and flavor symmetries, revealing non-universal flavor groups in moduli space.

Findings

Modular transformations unify CP and flavor symmetries.

The flavor group is non-universal across moduli space.

Different sectors can have distinct flavor structures.

Abstract

Modular transformations of string theory are shown to play a crucial role in the discussion of discrete flavor symmetries in the Standard Model. They include CP transformations and provide a unification of CP with traditional flavor symmetries within the framework of the "eclectic flavor" scheme. The unified flavor group is non-universal in moduli space and exhibits the phenomenon of "Local Flavor Unification", where different sectors of the theory (like quarks and leptons) can be subject to different flavor structures.