Search for Leptons Produced in Association with Prompt Muons in Hadronic Interactions

We present the results of a search for leptons produced in coincidence with a prompt muon in neutron-beryllium collisions at 300 GeV/c. The experiment was sensitive to trigger muons and associated leptons of both low momentum and low transverse momentum. A clear ${\mu }^{\pm }{\mu }^{\mp }$ signal was found, but no significant ${\mu }^{\pm }{e}^{\mp }$ signal was observed. We report an upper limit for associated charmed-particle production [${\sigma }_{C\overline{C}}·B(C\to \mu +X)·B(C\to e+X)$] of < 340 nb/nucleon, at the 95% confidence level.