Particle identification with the NA62 RICH detector

NA62 is a new generation kaon experiment at the CERN SPS aiming at studying rare and forbidden decays. One of main challenges of the experiment is the suppression of background decay channels with branching ratios up to 10 orders of magnitude higher than the signal and with similar experimental signatures. To provide such suppression, a powerful particle identification (PID) is needed. A key element of PID in NA62 is the Ring Imaging Cherenkov (RICH) detector. The RICH has successfully operated during the 2016–2018 data taking periods, being essential in the measurement of the branching ratio of the K+→π+νν̄ decay. The detector was also used for searches for lepton number violation in 3-track kaon decays. The results on the π/μ and π/e separation directly measured with the data for the aforementioned decays are presented.