Rare Kaon Decays

Historically important in the development of Standard Model (SM) particle physics, rare kaon decays are still a privileged tool for looking beyond it. The main reasons to continue study test CKM quark-mixing and CP-violation paradigm, make quantitative comparisons with B sector, search explicit violations SM. Current research on focuses mostly [Formula: see text] decays, which predicted good accuracy within SM beyond. Experimentally, these especially that charged kaon, have long history. Their theoretical importance is matched only by their experimental difficulty. This article reviews progress past 10 years, describes state art, looks toward future perspectives.