CP violation in Kaon decays and neutral kaon mixing beyond the standard model

Matter-antimatter asymmetry is an essential ingredient for baryogenesis and a remains an interesting challenge for theorists. In the standard model of particle physics, it is related to the violation of CP (charge-Parity) “symmetry”. A first kind of CP violation (called indirect) was discovered experimentally more than 50 years ago. After tremendous experimental effort, a second kind of CP violation (called direct) at the end of the 90’s. Both effects were discovered in kaon decays. Although these effects are tiny, there are now extremely well measured, therefore CP violation should provide crucial tests on the standard model and on models of new physics. However, from a theoretical perspective, the relevant computation turned out be a very long standing challenge: the first complete “prediction” of direct CP violation in kaon decay has only been published last year.
In the first part of the talk, I will present the status and the prospects for the computation of kaon decay amplitudes.
I will then turn to neutral kaon mixing, the oscillation of a kaon with its anti-particle, which is also related to CP violation. In particular I will discuss the Beyond-the-Standard-Model contributions with an emphasis on the role of the renormalization.