CP-violating phases in the CKM matrix in orbifold compactifications

TL;DR

This paper investigates CP-violation arising from orbifold compactifications in string theory, analyzing effects in kaon systems and neutron EDM, considering fixed and non-fixed points of the T-modulus.

Contribution

It provides a detailed study of CP-violation mechanisms in orbifold models, focusing on the role of the T-modulus at fixed points and on the unit circle.

Findings

CP-violation can occur at fixed points of the modular group.

Non-fixed T-modulus values also influence CP-violation.

Implications for kaon CP-violation and neutron EDM are discussed.

Abstract

The picture of CP-violation in orbifold compactifications in which the $T$-modulus is at a complex fixed point of the modular group is studied. CP-violation in the neutral kaon system and in the neutron electric dipole moment are both discussed. The situation where the $T$-modulus takes complex values on the unit circle which are not at a fixed point is also discussed.