Related papers: Pomeron physics: an update
Coherence phenomena, the increase with energy of coherence length and the non-universality of parton structure of the effective Pomeron are explained. New hard phenomena directly calculable in QCD such as diffractive electroproduction of…
Coherence phenomena, and the non-universality of parton structure of the effective Pomeron are explained. New hard phenomena directly calculable in QCD such as diffractive electroproduction of states with $M^2\ll Q^2$ as well as new options…
Diffraction is an old subject which has received much interest in recent years due to the advent of diffractive hard scattering. We discuss some theoretical models and experimental results that have shown new striking effects, e.g. rapidity…
A Pomeron phenomenon remains a mystery. A short review of the experimental situation in diffractive physics and an account of some spectacular manifestations of the Pomeron are given.
Soft pomeron fits reproduce all zero-Q2 data for light quarks, but run into problems at HERA for heavy mesons and for high Q2, and at the Tevatron for W diffractive production. I review the basic properties of the soft pomeron, and outline…
Measurements of soft and hard diffractive processes have been performed at the Tevatron p-pbar collider during the past decade. Diffractive events are studied by means of identification of one or more rapidity gaps and/or a leading…
Two key issues in the application of perturbative QCD and Regge predictions to high energy processes are whether the hard and soft pomerons should be considered as two separate distinct exchanges and whether the Regge intercepts are Q^2…
At present there is no correct theory of evolution of F_2(x,Q^2) at small x. It is a mixture of hard and soft pomeron exchange and perturbative QCD very successfully describes the evolution of the hard-pomeron component. This allows the…
A wide variety of experimental data in hadronic reactions are described in terms of the exchange of an object called the soft pomeron. It is nonperturbative in origin and is perhaps associated with glueballs. The HERA measurements of $\nu…
Regge theory provides a very simple and economical description of data for (i) the proton structure function with x<0.07 and all available Q^2 values, (ii) the charm structure function, and (iii) gamma p --> J/psi p. The data are all in…
We summarize the main features of available experimental results on soft and hard diffraction and draw conclusions about the nature of the pomeron.
I discuss the theoretical status of the `soft' pomeron and its place in describing generic diffractive processes. The role of perturbative QCD (pQCD) corrections is considered, in particular in the context of quasi-elastic vector meson…
This review focuses on diffractive physics, which involves the long-range interactions of the strong nuclear force at high energies described by SU(3) gauge symmetry. It is expected that diffractive processes account for nearly 40% of the…
We review the evidence for the presence of a hard singularity in soft forward amplitudes, and give an estimate of its trajectory and couplings.
QCD predicts the existence of the perturbative Pomeron and of the Odderon. But both of them appear to be rather difficult to observe experimentally. We describe the experimental status of these two objects, discuss possible reasons for…
I briefly review: (a) some recent developments in the theory of hard scattering in QCD with polarized beams, and (b) coherent hard diffraction (that is, hard scattering in diffractive events, with the Pomeron behaving in an apparently…
A comparative phenomenological analysis of Regge models with and without a hard Pomeron component is performed using a common set of recently updated data. It is shown that the data at small $x$ do not indicate explicitly the presence of…
Diffractive meson production at HERA offers interesting possibilities to investigate diffractive processes and thus to learn something about the properties of the pomeron. The most succesful phenomenological description of the pomeron so…
New small-$x$ data indicate the existence of two pomerons: the usual soft pomeron with intercept close to 1.08, and a hard pomeron with intercept about 1.4
We discuss some problems concerning the application of perturbative QCD to high energy processes. In particular for hard processes, we analyze higher order and higher twist corrections. It is argued that these effects are of great…