Muon scattering

The latest generation of muon experiments at CERN and Fermilab have covered a broad physics program reaching high standards with respect to both statistical and systematical uncertainties of their data. They have proven to be an excellent means of studying the structure functions of nucleons over a wide range of Q2 and of investigating fine details, for example deviations of the point-like structure of heavy nuclei from that observed with free nucleons. Detailed confrontations of the measured Q2 evolution with expectations from perturbative QCD have yielded smaller numerical values of the mass scale parameter Λ than previously assumed. The two CERN experiments are presently working on a completion of their structure function analyses, which will result in even more precise data sets. Extensive investigations of multimuon final states have led to some understanding of the mechanism of J//PSI/ and open charm production. The experiment of the BCDMS group has proven to be accurate enough to observe interference effects between the electromagnetic and the weak neutral current as predicted by electroweak theories and to determine sin2 theta /sub w/ . An aspect covered in an earlier article concerns the high statistics study of the dynamics of hadron production including the successful search for subtle phenomena originating only from higher order perturbative QCD effects. Here a new phase of the European Muon Collaboration experiment is in progress