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

The neutral pion form factor at NA62

In 2007 the NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger selecting events with electrons in the final state. The kaon beam represents a rich source of tagged neutral pion decays in vacuum. The electromagnetic transition form factor slope of the π0 in the time-like region has been measured from about 106 fully reconstructed π0 Dalitz decays collected in 2007. The preliminary result a = (3.68 ± 0.51stat ± 0.25syst) × 10-2 is the most precise to date. This value is compatible with theoretical expectations and consistent with the previous measurements

Status of the CERN NA62 Experiment

The K+ -> pi0 nu nubar decay is one of the theoretically cleanest meson decays to look for indirect effects of new physics in a complementary way to direct searches at the LHC. The NA62 experiment at CERN SPS is designed to measure the branching ratio of this decay with 10% precision. NA62 is taking data since 2014, eventually reaching the final designed beam intensity. Using a sample of data taken in 2015, the experimental performances in view of the K+ -> pi0 nu nubar branching ratio measurement is reporte