$\mathcal{CP}$ Violation from String Theory

TL;DR

This paper explores how string theory naturally incorporates and breaks CP symmetry, linking heavy string modes and flavor symmetry to potential origins of matter-antimatter asymmetry in the universe.

Contribution

It proposes a novel mechanism for CP violation in string theory through heavy modes and flavor symmetry interplay.

Findings

Heavy string modes can break CP symmetry in low-energy theories.

CP violation may explain cosmological matter-antimatter asymmetry.

A new embedding of CP symmetry within string theory framework.

Abstract

We identify a natural way to embed $\mathcal{CP}$ symmetry and its violation in string theory. The $\mathcal{CP}$ symmetry of the low energy effective theory is broken by the presence of heavy string modes. $\mathcal{CP}$ violation is the result of an interplay of $\mathcal{CP}$ and flavor symmetry. $\mathcal{CP}$ violating decays of the heavy modes could originate a cosmological matter-antimatter asymmetry.