EXPONENTIATION OF MULTIPARTICLE AMPLITUDES IN SCALAR THEORIES .2. UNIVERSALITY OF THE EXPONENT

It has been shown recently that the amplitude of the creation of n rea l scalar particles by one virtual boson near the n-particle threshold exhibits exponential behavior at n similar to 1/lambda. We extend this result to the processes;of multiparticle production at threshold by t wo virtual bosons. We find that both the tree-level amplitude and lead ing in n loop corrections have the same exponential behavior, with the common exponent for 1 --> n and 2 --> n processes, for various kinema tics. This result strongly indicates that the exponent for multipartic le amplitudes is independent of the initial state and that there may e xist a semiclassical approach to the study of multiparticle production .