A critical evaluation of theories of direct electron pair production by muons

The development of the theory of direct pair production by relativistic muons is traced in an attempt to reconcile the existing theoretical expressions for the cross section. The interrelation of the theoretical treatments and the shortcomings of approximate formulae are examined. Cross sections are expressed in a form suitable for numerical evaluation and a direct comparison of the formulae of various authors is made. Numerical calculations of energy loss -dE/dx are presented and compared with computations of other authors.