Soft Process in Very High Energy Proton-Proton Collisions

Abstract

Soft processes in terms of fragmentation of high-p⊥ and low-p⊥ jets are considered in relation to the high and low momentum transfer mechanisms that produce them. The evolution of high-p⊥ jets can be reliably described based on perturbative QCD radiation and hadronization models tuned at present energies and we give realistic predictions for the properties of such jets at very high energies. The modelling of low-p⊥ spectator jets and minimum bias events, on the other hand, involve important uncertain elements regarding the interaction mechanism and the resulting colour field structure which lead to large uncertainties in the resulting predictions. DifFractive scattering is discussed in terms of the nature of the pomeron and its interactions, in particular the possibility of parton constituents in the pomeron and “hard diffractive scattering” is considered.