Some time ago1, it has been suggested that a pomeron model la Donnachie-Landshoff2, where the leading singularity in the complex j plane is given by a simple pole, could not provide the best fits to the data for total cross sections, and for the ratio ρ of the real to the imaginary part of the forward elastic scattering amplitude. This conclusion was based on an analysis of all available data a...

I review the recent results in the field of QCD at high energy presented to this Conference. In particular, I will concentrate on measurements of αS from studies of event structures and jet rates, jet production in hadronic collisions, and heavy quark production.

The contribution to diffraction dissociation of virtual photons due to quasi-elastic scattering of the q-¯ q component is calculated in the framework of the QCD dipole picture. Both longitudinal and transverse components of the cross-section are given. It is shown that, at fixed mass of the diffractively produced system, quantum mechanical interference plays an important rôle. Phenomenological ...

I show that factorization for hard processes in QCD is also valid when the detected particles are polarized, and that the proof of the theorem determines the operator form for the parton densities. Particular attention is given to the case of transversely polarized incoming hadrons.

We describe the resummation of singular distributions at partonic threshold in heavy quark production, generalizing results for Drell-Yan and other electroweak hard-scattering processes.

Diffractive scattering involves exchange of a Pomeron to make a rapidity gap. It is normally assumed that to get a hard scattering in diffraction, one may treat the Pomeron as an ordinary particle, which has distributions of gluons and quarks. We show that this is not so: When we use perturbative QCD, there is a breakdown of the factorization theorem. The whole Pomeron can initiate the hard sca...