A topological expansion for high-energy hadronic collisions: (II). s-channel discontinuities and multiparticle content

Abstract

In a companion paper, we have defined a topological expansion for high-energy hadronic processes, and in particular discussed its asymptotic relation with reggeon field theory from a t-channel point of view. Here we turn to the study of s-channel unitarity, which is automatically incorporated in our scheme. We first give a simple topological classification of s-channel discontinuities at high energies, for which some interference terms are argued to be negligible. We then find that the unitarity equation is decomposed in a sum of positive definite terms related to various classes of events (generalized gap expansion). In the enhanced graph approximation we derive a cut reggeon field theory having three pomeron fields and four couplings, which is automatically consistent with the previous positivity requirements. Unitarity to all orders in 1/ N (where U( N) is the internal symmetry group) constraints all couplings to be proportional, consistently (except for a possible ambiguity) with the cutting rules of Abramovskii et al.