Soft and hard hadronic processes in the nonperturbative approach of QCD

Abstract

A two-component model to analyze both soft and hard hadronic processes at high energies is suggested. The model is based on the topological $1/N$ expansion of the scattering amplitude and the theory of the supercritical Pomeron. The longitudinal component is given by the string model and determines the behavior of the cross section on longitudinal variables. The dependence on the transverse momentum is calculated on the basis of a two-gluon Pomeron model in which the Pomeron is modeled as an exchange of two nonperturbative gluons whose propagator is finite at ${q}^{2}=0.$ Hard scattering of quarks on the ends of quark-gluon strings is calculated as a sequence of multi-Pomeron exchanges. It is shown that the propagator which vanishes as ${(q}^{2}{)}^{\ensuremath{-}3}$ or faster allows one to reproduce hard distributions of secondary hadrons. The model is used to analyze the inclusive spectra of hadrons on the Feynman variable ${x}_{F}$ and transverse momentum ${p}_{\ensuremath{\perp}}$ up to 10 $\mathrm{GeV}/c$ in a wide energy interval.