Charm production in 400 GeV/c proton-emulsion interactions

5032 proton-emulsion interactions at 400 GeV/c momentum have been carefully scrutinized for production and decay of charged charm particles. In order to detect these decays, shower tracks from 3056 stars have been followed to a maximum length of 1 mm and those from 1976 stars up to 2 mm. A total of 23 three-prong charm-like candidates have been recorded in the forward cone. The background due to γ-overlap on a shower track, trident/pseudo-trident production and secondary interactions is estimated to be 15. Attributing the signal of 8 events to Λc+ and assuming the branching ratio of Λc+ → 3 prong to be 0.6 and tΛc to be 10-13 sec we obtain the production cross section to be 106±39µb/nucleon. Out of these 8 events one example of semileptonic decay of Λc+ is seen