Epsilon'/Epsilon in the Standard Model: Theoretical Update

TL;DR

This paper provides a detailed theoretical update on epsilon'/epsilon in the Standard Model, incorporating isospin breaking, strong and electromagnetic corrections, and chiral loop effects, resulting in a refined estimate of the CP-violating ratio.

Contribution

It offers a comprehensive analysis of isospin breaking effects and their impact on epsilon'/epsilon, including next-to-leading order corrections in chiral perturbation theory.

Findings

Re(epsilon'/epsilon) = (19^{+11}_{-9}) 10^{-4}

Quantifies the impact of isospin breaking and electromagnetic corrections

Refines previous estimates of direct CP violation in K decays

Abstract

A complete analysis of isospin breaking in K to 2 pion amplitudes, including both strong and electromagnetic corrections at next-to-leading order in chiral perturbation theory, has been achieved recently.We discuss the implication of these effects, together with the previously known chiral loop corrections, on the direct CP-violating ratio epsilon'/epsilon. One finds Re(epsilon'/epsilon) = (19^{+11}_{-9}) 10^{-4}.