QCD parton model and high-energy hadronic collisions

Hadron-hadron collisions at high energies are studied by considering the scattering between their constituent partons. A model, based largely on the quantum-chromodynamics-improved parton model, is formulated to calculate the collision parameters such as the cross sections, the forward slope parameter, and the ratio of the real to the imaginary parts of the forward scattering amplitude. The energy dependence of these collision parameters is associated with semihard scatterings of gluons and quarks in the hadrons. Numerical results of the model for proton-proton and proton-antiproton scattering are presented, and are found to be in general agreement with experimental data. This QCD-motivated model for hadron-hadron collisions is then further developed to describe the nucleon-nucleus scattering. Results on the jet cross sections, average jet multiplicities, and jet-multiplicity fluctuations in a high energy proton-proton or proton-antiproton collision are also presented.