Electrodynamic processes in colliding beams of high-energy particles

A classification is presented for the processes in quantum electrodynamics at high energy. The classification is based not on perturbation theory but on the character of the asymptotic behavior of the amplitudes and cross sections at high energy. A simple procedure is described for finding the asymptotic forms of the amplitudes of different processes from the form of the intermediate state in the crossing channel. A review is presented of the theoretical results for processes with cross sections that do not decrease with increasing energy. Double-logarithmic asymptotic expressions are obtained for processes with cross sections that decrease with increasing energy by summing the principle terms of the perturbation-theory series.