PAIR PRODUCTION IN COLLISIONS BETWEEN MUONS AND ATOMIC ELECTRONS

The cross section for the production of electron-positron pairs in col lisions between muons and atomic electrons is calculated, and muon ene rgy losses are determined. The process is described by 12 Feynman diag rams. Near the reaction threshold, interference terms are operative, l eading to unequal cross sections for positive and negative muons and r educing the cross sections by a factor of about six. As the muon energ y is increased, the relative contribution of the interference terms de creases, falling below 3% for E > 30 GeV. The elastic atomic form fact or calculated on the basis of the Thomas-Fermi model is used to take i nto account the binding of atomic electrons. The results of numerical calculations are approximated by simple analytic expressions to a prec ision not poorer than 5%.