Rapidity gap expansion for secondary-reggeon-dominated amplitudes

Abstract

We discuss a model for high-energy amplitudes dominated by secondary reggeons based on threshold effects for the appearance of large rapidity gaps. This model can be reinterpreted in terms of itsJ-plane singularity structure: real and complex poles and a cut. In contrast to a simple Regge-pole approach, it turns out to be an appropriate scheme to handle the difficulties associated with the phenomenology of ρ and A2 exchanges. In this way the present expansion can be thought of as a phenomenologically adequate perturbative treatment of reggeon field theory.