Antineutrino Charm Production and Pentaquark Search in the CHORUS Experiment

During the years between 1994 and 1997, the emulsion target of the CHORUS experiment was exposed to the wide band neutrino beam of the CERN SPS of 27 GeV average energy collecting about 106 neutrino interactions. A measurement of induced charm production and search for anticharmed pentaquark (0 c ) have been performed by using the presence of a 6% component in the beam. By requiring a positive muon charge as determined by the CHORUS muon spectrometer, 46 -induced charm events were observed with an estimated background of 5:20:4 events. By using the data sample, anticharmed pentaquark ( 0 c ) have been searched and no evidence is found. Based on the null observation, the limit on the 0 c production is found as a function of di eren t possible 0 c lifetimes. The tightest bound is 0 c = < 0.039 at 90% C.L by assuming that 0 c lifetime is equal to 0.5 c D 0. (not complete)