Predictions for total inelastic cross-sections for photon induced processes
are discussed in the context of the QCD-inspired minijet model. Large
theoretical uncertainties exist, some of them related to the parton
distributions of hadrons in impact parameter space. A model for such
distribution is presented, based on soft gluon summation. This model
incorporates (the salient features of distributions obtained from) the
intrinsic transverse momentum behaviour of hadrons. Under the assumption that
the intrinsic behaviour is dominated by soft gluon emission stimulated by the
scattering process, the b-spectrum becomes softer and softer as the scattering
energy increases. In minijet models for the inclusive cross-sections, this will
counter the increase from σjet​ .Comment: 11 pages, two postscript figures, latex, uses epsfig.sty, a4wide.sty
full postscript file of the paper is available at
http://hpteor.lnf.infn.it/pancheri/starelesna.p