Review of multimuon production by muons

Production of 2, 3, 4, and 5-muon final states by high-energy muons at Fermilab and CERN SPS is reviewed. Sixty-three 4μ, 5μ, and odd-sign 3μ final states have been observed. Corresponding limits on muoproduction of UPSILON, b anti b, and anti M0 are summarized. Precise data on the Q2 and nu-dependence of muo-produced elastic-psi, inelastic-psi, and open-charm states are presented. Elastic and inelastic psi muoproduction results are extended to include distributions in production and decay angle, elasticity, and momentum transfer to hadrons. Calculations using the lowest-order photon-gluon-fusion graph can be adjusted to reproduce the nu-dependence of elastic psi production, the nu and Q2 dependence of open charm production, and the combined (hidden + open) charm production cross section. Unfortunately, the model does not account for the angular distributions and Q2-dependence observed for elastic psi production