Related papers: General Issues in Small-x and Diffractive Physics
In the present talk diffraction in deep inelastic scattering is discussed in the framework of the semiclassical approach. The main emphasis is on the possibility of a consistent semiclassical description of both hard and soft colour singlet…
The process of soft diffractive dissociation in hadronic collisions is discussed in the framework of the Miettinen-Pumplin model. A good description of the data in the ISR-Tevatron energy range is found. Predictions for the total, elastic…
The contribution of subleading reggeons to the diffractive structure function ${dF_{2}^D / dx_{\funp} dt}$ is estimated from the soft physics data. This contribution leads in a natural way to the violation of the factorization property of…
An introduction and summary is given of the main results achieved by working group 1: Structure Functions in Deep Inelastic Scattering at HERA. The prospects were discussed of future measurements of the structure functions $F_{2}, F_{L},…
We analyze the fermion density of the one-dimensional Hubbard model using bosonization and numerical DMRG calculations. For finite systems we find a relatively sharp crossover even for moderate short range interactions into a region with…
Measurements of diffractive phenomena observed at HERA and the Tevatron are reviewed. A short introduction to the theoretical background is presented where colour singlet exchange reactions are discussed and the diffractive contribution and…
Recent HERA data on structure functions and reduced cross-sections are presented and their significance for our understanding of the low-x region is discussed.
Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as…
Results on elastic vector meson production at HERA are presented in the framework of perturbative QCD. The energy dependence of the cross section for J/Psi photoproduction and for rho electroproduction is studied. A full polarisation…
The exclusive diffractive production of vector mesons and real photons in ep collisions has been studied at HERA in a wide kinematic range. Here the most recent experimental results are presented together with a Regge-type model and…
We present a review of the latest exclusive diffraction results achieved at HERA, discussing in particular the $W$ and $t$ dependence of the measured cross-sections in both DIS and photo-production regimes.
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…
We explore the possibility whether the gluon helicity distribution $\Delta G(x)$ can be extracted from a comparison of experimental data on the longitudinal spin-spin asymmetry $A_{LL}$ in $\gamma p$ diffractive deep inelastic scattering…
Results from the H1 and ZEUS experiments at HERA on deep inelastic scattering are reviewed. The data lead to a consistent picture of a steep rise in the F_2 structure function and in the gluon density within the proton. Important new…
The HERA data at large $Q^2$ and small-$x$ investigate large distances on the light-cone. At such large distances the scattered quarks can maintain their colour identity by polarizing the vacuum as they transfer energy to it. We calculate…
We present a novel Monte-Carlo implementation of dynamic colour screening via multiple exchanges of semi-soft gluons as a basic QCD mechanism to understand diffractive electron-proton scattering at the HERA collider. Based on the kinematics…
The rich experimental landscape of exclusive vector meson production at the high energy electron-proton collider HERA is reviewed, with emphasis on the transition from soft to hard diffraction and QCD interpretations.
The QCD dipole picture of BFKL dynamics provides an attractive theoretical approach to the study of the QCD (resummed) perturbative expansion of small-x physics and more generally to hard high-energy processes. We discuss applications to…
Several topics in hadron physics at different scales of resolution are discussed. First, deep-inelastic scattering from nucleons and nuclei is viewed in a light-cone coordinate space picture. Then the smooth transition from parton to hadron…
A brief review is given on the physics potential of HERA beyond the presently approved programme. Questions of particular interest include QCD in a regime of weak coupling and high partonic densities achieved in eA collisions and spin…