Multi-Regge factorization in inclusive two-particle production

Abstract

We consider in detail the multi-Regge expansion for the eight-particle amplitude with one triple-Regge and two double-Regge couplings. We show that under trivial conditions and with a suitable choice of helicity contours, the double-Regge couplings in the multi-Regge (MR) limit are identical, to leading order, with couplings obtained in the mixed helicity-pole-Regge-pole (HPRP) limit appropriate to inclusive reactions. Since we do not need to introduce any dependences on any additional variables, our conditions are somewhat simpler than the results of others. As a plausibility argument for the identity of the MR and HPRP limit, we present an intuitive picture of how helicity poles may be visualized at the triple-Regge vertex. Assuming the mentioned identity, we calculate the diffractive contribution to ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}X$ and discuss the problem of isolating this mechanism experimentally. We propose experimental tests for the identity of the couplings and relate this to the problem of observing the ${A}_{1}$.