Search for K+→π+ ν̅ν at NA62

The K+→π+ ν̅ν branching ratio is one of the key observables to test the Standard Model. The NA62 experiment has been designed to measure this branching ratio with a 10% precision. Most of the experiment systems have been commissioned during 2014 and 2015 runs and physics data have been recorded. The analysis of this data shows performances close to the nominal ones

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