Speaker:  Giuseppe Ruggiero

A precision measurement of the ratio RK of the rates of kaon leptonic decays K+- --> e+- nu and K+- --> mu+- nu with the full minimum bias data sample collected with low intensity 75 GeV/c beam by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analyzing ~150,000 reconstructed K+- --> e+- nu candidates with 11% background contamination, has a record precision of 0.4% and is in agreement with the Standard Model expectation.