Related papers: The Two Pomerons
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…
The diffractive 2-jet production reactions in the proton-proton and lepton-proton processes are discussed. It is shown that they may be very suitable for studying the properties of the pomeron couplings with quarks and hadrons in future…
The results of experiments at hadron colliders probing the structure of the pomeron through hard diffraction are reviewed. Some results on deep inelastic diffractive scattering obtained at HERA are also discussed and placed in perspective.…
The first measurement of diffractive processes in deep inelastic scattering at the HERA collider is analysed in terms of a "soft" pomeron exchange model. The partonic structure of the pomeron which emerges in this picture is determined…
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at…
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
This report contains selected recent highlights from experimental studies of soft and semi-hard strong interactions from the Large Hadron Collider, HERA and the Tevatron. The subject is broken down into diffractive and non-diffractive…
We propose a means of distinguishing between gluon- and quark-seeded systems that may in principle be measured in deep inelastic lepton scattering. As a particular application, we discuss those HERA data on deep inelastic $ep$ scattering…
Central exclusive production in hadron-hadron collisions at high energies, for example p + p -> p + X + p, where the "+" represents a large rapidity gap, is a valuable process for spectroscopy of mesonic states X. At collider energies the…
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…
Glueballs are considered to be bound states of constituent gluons. Relativistic wave equation for two massive gluons interacting by the funnel-type potential is analyzed. Using two exact asymptotic solutions of the equation, we derive an…
We discuss the production of hadronic resonances in very peripheral heavy ion collisions, where the ions collide with impact parameter larger than twice the nuclear radius and remain intact after the collision. We compare the resonance…
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 brief review on the Dipole Pomeron model is given. The model not only describes data on hadron-hadron interactions, but also allows to describe data on the proton structure function with a $Q^2$ independent intercept. Moreover the chosen…
Inclusive jet cross sections for events with a large rapidity gap with respect to the proton direction from the reaction $ep \rightarrow jet \; + \; X$ with quasi-real photons have been measured with the ZEUS detector. The cross sections…
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…
Key issues in pomeron physics include whether the hard and soft pomerons are distinct objects, and whether the hard pomeron is already present in amplitudes at $Q^2=0$. It is urgent to learn how to combine perturbative and nonperturbative…
The ZEUS data on the charm structure function F_2^c at small x fit well to a single power of x, corresponding to the exchange of a hard pomeron that is flavour-blind. When combined with the contribution from the exchange of a soft pomeron,…
We have substantially extended our analysis of the partonic content of the pomeron. Ambiguities in the normalization of the pomeron flux and the possiblity of a direct coupling of the pomeron to single quarks are discussed, yielding two…
Color singlet two gluon exchange provides a perturbative model for the pomeron. This mechanism is thought to explain the production of rapidity gaps in hard dijet events at the Tevatron. It is shown that in $qQ$ scattering via two gluon…