Leading Effect of CP Violation with Four Generations

TL;DR

This paper investigates how a fourth quark generation could significantly enhance CP violation effects in quark processes, especially in B meson decays, by analyzing the CKM matrix and Jarlskog invariants.

Contribution

It provides a theoretical analysis of CP violation in a four-generation Standard Model, highlighting the potential for larger effects due to heavy fourth-generation quarks.

Findings

Leading CP violation effects are amplified by large fourth-generation quark masses.

Possible large CP violation in b → s processes is discussed.

The study uses small mass and angle expansions to identify dominant effects.

Abstract

In the Standard Model with a fourth generation of quarks, we study the relation between the Jarlskog invariants and the triangle areas in the 4-by-4 CKM matrix. To identify the leading effects that may probe the CP violation in processes involving quarks, we invoke small mass and small angle expansions, and show that these leading effects are enhanced considerably compared to the three generation case by the large masses of fourth generation quarks. We discuss the leading effect in several cases, in particular the possibility of large CP violation in $ b \to s $ processes, which echoes the heightened recent interest because of experimental hints.