Kaon experiments at CERN: recent results and prospects

TL;DR

Recent CERN kaon decay experiments have yielded precise measurements consistent with the Standard Model and have provided new tests of Chiral Perturbation Theory, with future plans to measure ultra-rare decay modes to probe fundamental physics.

Contribution

This paper reports recent experimental results on kaon decays from CERN, including precise measurements and tests of theoretical models, and outlines future experimental prospects.

Findings

RK ratio measurement agrees with Standard Model

New decay measurements test Chiral Perturbation Theory

Planned ultra-rare decay measurement aims to challenge Standard Model

Abstract

Recent results from the NA48/2 and NA62 kaon decay-in-flight experiments at CERN are presented. A precision measurement of the helicity-suppressed ratio RK of the K+- to e+- nu and K+- to mu+- nu decay rates has been performed using the full dedicated data set collected by the NA62 experiment (RK phase); the result is in agreement with the Standard Model expectation. New measurements of the K+- to pi+- gamma gamma decay at the NA48/2 and NA62 experiments provide further tests of the Chiral Perturbation Theory. A planned measurement of the branching ratio of the ultra-rare K+ to pi+ nu anti-nu decay at 10% precision is expected to represent a powerful test of the Standard Model.