Exponentiation of multiparticle amplitudes in scalar theories

M. V. Libanov, V. A. Rubakov, D. T. Son, S. V. Troitsky
1994 Physical Review D, Particles and fields  
It is argued that the amplitudes of the production of n soft scalar particles by one or a few energetic ones in theories like λϕ^4 has the exponential form, A_n∝√(n!)[1λF(λ n,ϵ)], in the regime λ→ 0, λ n=fixed, ϵ=fixed, where ϵ is the typical kinetic energy of outgoing particles. Existing results support this conjecture. Several new analytical and numerical results in favor of the exponential behavior of multiparticle amplitudes are presented.
doi:10.1103/physrevd.50.7553 pmid:10017739 fatcat:r3el445znrdtxdkdg6qghvgpwa