Rare kaon decays and CP violation

Abstract

Owing to the strong suppression of flavour-changing neutral-current transitions in the Standard Model, rare kaon decays constitute a superb tool to constrain hypothetical new-physics interactions. At the same time, they provide many interesting tests of the Standard Model itself, being sensitive both to short-distance electroweak scales and to the long-distance QCD dynamics. A brief overview of the current status is presented. The Standard Model prediction for the direct CP-violating ratio ${\epsilon }^{\prime }/\epsilon$ is also discussed.

Comments: Invited talk at Beauty 2019 (Ljubljana, Slovenia, 29 September - 4 October, 2019). 12 pages, 9 figures. arXiv admin note: text overlap with arXiv:1911.06211, arXiv:1208.2134