CP violation in the CKM mixing for degenerate quark masses

TL;DR

This paper explores how approximate quark mass degeneracy influences CP violation in the CKM matrix, revealing a non-trivial role of degenerate symmetry that challenges traditional views and aids flavor model development.

Contribution

It demonstrates that degenerate symmetry can contribute to CP violation even with quark mass degeneracy, providing new insights into flavor physics.

Findings

Degenerate symmetry influences CP violation in the CKM matrix.

Mass hierarchy is related to the origin of CP violation.

The role of degenerate symmetry is clarified in flavor mixing models.

Abstract

CP violation in the CKM mixing is discussed for the case of quark mass degeneracy that is approximate in the quark mass hierarchy limit. Differing from the traditional understanding of CP vanishing for degenerate masses, we find degenerate symmetry plays a non-trivial role in CP violation. The minimal flavor structure model is reviewed to demonstrate the role of degenerate symmetry in quark flavor mixing, particularly in CP violation. This relation between mass hierarchy and CP violation helps us understand the origin of CP violation and assists the construction of the flavor model.