Total Cross-sections at very high energies: from protons to photons

Abstract

A model for both proton and photon total cross-sections is presented and compared with data. The model is based on the eikonal representation, with QCD mini-jets to drive the rise and soft gluon kt-resummation into the Infrared region to tame the excessive rise due to low-x perturbative gluons. We discuss the effects of a singular but integrable expression for the Infrared gluon spectrum on the high energy behaviour of the total cross-section expected in this model.

13 pages, 4 figures, Tenth Workshop on Non-Perturbative Quantum Chromodynamics at l'Institut Astrophysique de Paris, June 8-12, 2009