We report on the production of 158 trimuon and 637 dimuon events by 10.5-GeV/c muons incident on lead. The sensitivity of the experiment was typically 1 event per picobarn per nucleon. It is shown that the majority of the trimuon events are due to QED trident production. We present differential and total cross sections for this process and establish that muons obey Fermi-Dirac statistics at a confidence level of 8 standard deviations. Approximately 10% of the trimuons are due to other processes, most probably diffraction of the virtual photon. Upper limits on the production of particles with a three-muon decay mode and on inelastic virtual-photon Compton scattering are obtained. The dimuon events can be accounted for by tridents where one of the muons lies outside the acceptance of the apparatus and by the production of $\pi$ and $K$ mesons which subsequently decay into a muon. Upper limits on prompt single-muon production are given.

• Received 16 June 1980

DOI:https://doi.org/10.1103/PhysRevD.23.1