On the dynamics of multiple-reggeon exchange cuts

We discuss the circumstances under which multiple-pomeron exchange amplitudes can become iterative and show how the intermediate states involved in these amplitudes can be related to the states produced in diffractive dissociation. In order to obtain a soluble model, we construct a simple integral equation, which in an iterative way leads to a multi-pomeron exchange series, including contributions of cut mechanisms involving spectator particles. From a particular solution of this equation we are able to illustrate how the longitudinal-momentum distributions of the diffractive intermediate states influence the relative strength of the cuts. Further from a qualative analysis, we show why one might expect the helicity-non-flip vacuum amplitudes to have strong cuts, while all other amplitudes have weak cuts. A number of related points are also discussed.