Preliminary analysis of the performance of a rich counter for low-pT electron identification at the CERN p collider

Abstract A ring-imaging Cherenkov (RICH) counter with a 60 cm long freon (C 2 F 6 ) gas radiator has been used inside the UA2 detector at the CERN SPS p p Collider, the aim being to measure the amount of promptly produced electrons in the p T region 1–3 GeV/ c . About 800 000 events were recorded and the analysis is in progress. Results from a first analysis of a limited event-sample indicate that it will be possible to reach an e π rejection power of at least 10 −4 with the RICH counter.