CP violation during the electroweak sphaleron transitions

TL;DR

This paper investigates the potential for CP violation during electroweak sphaleron transitions by analyzing a semiclassical background, evaluating effective operators, and discussing implications for cold electroweak scenarios.

Contribution

It introduces a specific semiclassical background to estimate CP violation from the CKM phase and derives the scale dependence of related coefficients.

Findings

Quantifies CP violation magnitude during sphaleron transitions

Evaluates matrix elements of effective CP-violating operators

Discusses implications for cold electroweak scenarios

Abstract

We suggest a specific semiclassical background field, the so called pure gauge sphaleron explosion, to evaluate the magnitude of the CP violation stemming from the standard phase of the CKM matrix. We use it to evaluate the matrix elements of some next-to-leading order effective CP-violating operators suggested in the literature. We also derive the scale dependence of the corresponding coefficients. Finally, we discuss the expected magnitude of the CP violation in the cold electroweak scenario.