Application of Gribov calculus to two-body processes

Abstract

A new model for two-body high energy scattering is presented as part of an investigation into the phenomenological consequences of the non-planar structure of Reggeon-particle scattering. The model is a modification of the weak cut reggeized Absorption model for Pion-Nucleon scattering and is developed in form of a correlation modified quasi eikonal where the Reggeon and an arbitrary number of Pomerons are allowed to change the projection of the nucleon spin. A correlation parameter - the "Gribov c" - which has its origin in Gribov's theory, provides an indication about the failure of the traditional weak cut reggeized absorption model and restores its most profound shortcoming - the prediction of an incorrect phase behaviour of the helicity isovector nonflip amplitude in the reaction while retaining the model's attractive simplicity. The vertices of the Reggeon-calculus depend in general on the angle between the momenta of the exchanged reggepoles. By parameterizing this dependence we take into account the effective contribution of inelastic intermediate states in the unitarity expansion of the Regge-particle scattering amplitude. We obtain a reasonable phase energy description of the isovector amplitude. We demonstrate in detail the mechanism by which the correct phase behaviour is restored. The spin-structure of the amplitudes is investigat ed and observables of N scattering between 6 and 200 GeV/c within a range of momentum transfer of are being produced.