Charged charm production in proton-emulsion interactions at 400 GeV/c

Abstract

A study of charged charm production is made at 400 GeV incident energy of protons in nuclear emulsion. A total of 7005 primary stars have been scrutinized to look for charm particle decays in the forward cone within a decay distance of 100-1,000 µm (3,056 stars) and 100-2,000 µm (3,949 stars). In all 10 charm candidates decaying to ≈3 charged particles plus neutrals have been observed. Background due to secondary interactions for events of such topology is estimated to be ≈3. Background due to strange particle decays is estimated to be negligible. The rest of the events are attributed to Λ_c + and D ± decays. This leads to a value of 91±35 µb/nucleon for the total charged charm production cross section. Using production cross section for D ± from other experiments we obtain Λ_c + production cross section as 62±27 µb/nucleon. Two cases of pair production of charm have been seen.