Study of μe events produced in antineutrino interactions

A study is presented of μe events from an exposure of BEBC, filed with an heavyH2/Ne mixture, to a wide band antineutrino beam at the CERN SPS. The promptμ+e− rate, based on the observation of 45 events withpμ>4 GeV/c andpe>0.8 GeV/c, is found to be 0.31±0.05±0.02%, in agreement with previous determinations made on much smaller statistics. The differential kinematical variables characterizing the events and the content of strange particles are as expected for the production of charmed hadrons which subsequently decay semi-leptonically. An upper limit of 2.0±10−4 at 90% C.L. is given for the production rate of promptμ+e+ events. No evidence is found for a significant production of Beauty hadrons.