Are CP Violating Effects in the Standard Model Really Tiny?

TL;DR

This paper derives an effective bosonic action for the Standard Model, revealing that CP violation effects are larger than previously estimated and not suppressed by light quark Yukawa couplings.

Contribution

It provides a novel calculation of CP-violating operators in the Standard Model's bosonic sector, challenging existing bounds on CP violation.

Findings

CP violation in the bosonic sector is not suppressed by light quark Yukawas

Effective CP violation exceeds bounds set by the Jarlskog determinant

Calculated the prefactor of next-to-leading order CP-violating operators

Abstract

We derive an effective action of the bosonic sector of the Standard Model by integrating out the fermionic degrees of freedom in the worldline approach. The CP violation due to the complex phase in the CKM matrix gives rise to CP-violating operators in the effective action. We calculate the prefactor of the appropriate next-to-leading order operators and give general estimates of CP violation in the bosonic sector of the Standard Model. In particular, we show that the effective CP violation for weak gauge fields is not suppressed by the Yukawa couplings of the light quarks and is much larger than the bound given by the Jarlskog determinant.