Dr Evgueni Goudzovski (University of Birmingham)
The results from the CERN kaon experiments are presented. A precision test of lepton universality by measurement of the helicity suppressed ratio of kaon leptonic decay rates BR(K --> e nu)/BR(K --> mu nu) has been performed with over 10^5 K+- --> e+- nu decays collected by the NA62 experiment in 2007-08. A record accuracy of 0.4% has been achieved, which constrains the parameter space of new physics models with extended Higgs sector. An improved upper limit on the rate of the lepton number violating decay K+- --> pi-+ mu+- mu+-, which is sensitive to the existence of Majorana neutrinos, has been established with a K+- sample collected by the NA48/2 experiment in 2003-04. A new precise measurement of the K+- --> pi0 mu+- nu (Kmu3) decay form factors with more than 3 million events collected by NA48/2 with a minimum trigger setup is presented, which is an indispensable input for the determination of the CKM matrix element |Vus| from semileptonic kaon decays. Finally, the status of a future experiment aiming to measure the rate of the ultra-rare flavour changing neutral current decay K+ --> pi+ nu nubar to a record 10% precision with a low background sample of about 100 decays is discussed.