Search for K+ to pi+ nu nubar at the NA62 experiment at CERN

The flavor physics sector allows us to explore the possible extensions of the Standard Model (SM) in a complementary approach to the direct searches conducted i.e. at the Large Hadron Collider (LHC). New physics contributions at high energy scales can manifest themselves in low energy phenomena provided that the observables are carefully chosen, precisely measured and compared to accurate predictions. A stringent test of the SM predictions is the observation of the rare decay K+ to pi+ nu nubar. The NA62 experiment at CERN is designed to measure the branching ratio (BR) of this decay with 10% precision. NA62 has been successfully launched in October 2014, took data in pilot runs in 2014 and 2015 achieving the commissioning of the detectors and the designed beam intensity. The NA62 experimental setup is described and the quality of data collected in view of the final measurement is reported.