2011/11/11 by Evgueni Goudzovski, Goudzovski, Evgueni
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #hep-ex
paper · pdf · doi:10.48550/arxiv.1111.2818
Talk given at the EPS HEP 2011 conference (Grenoble, 21-27 July 2011)
arxiv created 2011/11/11 · arxiv updated 2011/11/14
Searches for lepton flavour and lepton number violation in kaon decays by the NA48/2 and NA62 experiments at CERN are presented. A precision measurement of the helicity-suppressed ratio RK of the K --> e nu and K --> mu nu decay rates has been performed using the full data set collected by the NA62 collaboration in 2007. The data sample amounted to 145,958 reconstructed K --> e nu candidates with 11.0% background contamination. The result is RK = (2.488 +- 0.010) X 10-5, which is in agreement with the Standard Model expectation. An improved upper limit on the lepton number violating K+- --> pi-+ mu+- mu+- decay rate is also presented.