English

$\varepsilon'/\varepsilon$ in the Standard Model and Beyond: 2021

High Energy Physics - Phenomenology 2022-03-25 v1 High Energy Physics - Experiment High Energy Physics - Lattice

Abstract

The present status of the ratio ε/ε\varepsilon'/\varepsilon in the Standard Model (SM) is summarized. In particular we stress the differences between three approaches that attempt to calculate ε/ε\varepsilon'/\varepsilon within the SM: Lattice QCD, Dual QCD and Chiral Perturbation Theory. As presently there is still a significant room left for new physics (NP) contributions, we summarize the present status of the technology that has been recently developed with the goal to analyze ε/ε\varepsilon'/\varepsilon and its correlations with other observables within the Weak Effective Theory (WET) and the Standard Model Effective Field Theory (SMEFT). We also make a few comments on the interpretation of the main dynamics behind the ΔI=1/2\Delta I=1/2 rule in KππK\to\pi\pi decays.

Keywords

Cite

@article{arxiv.2203.12632,
  title  = {$\varepsilon'/\varepsilon$ in the Standard Model and Beyond: 2021},
  author = {Andrzej J. Buras},
  journal= {arXiv preprint arXiv:2203.12632},
  year   = {2022}
}

Comments

16 pages, no figures, Contribution to the CKM Workshop 2021, 22-26 November 2021, Melbourne, Australia. arXiv admin note: text overlap with arXiv:1912.12306

R2 v1 2026-06-24T10:23:48.575Z