μ-pair production: current problems and prospects

As the experimental status of +-pair production becomes clearer and more refined each year the theoretical situation is still very unsatisfactory. The question of whether or not factorization is valid in μ-pair production still has not been definitively settled. Questions of A dependence and transverse momentum broadening of μ-pairs in nuclei have just begun to get theoretical attention. These and other topics have been discussed, and sometimes debated, at this workshop. This summary concentrates on those aspects of μ-pair production which are controversial or which have received less attention in the past than was deserved. Many of the topics not discussed in this summary have been reviewed in the opening talk of this workshop by E. Berger