Related papers: Interplay of Hard and Soft Physics in Small $x$ De…
The propagation of colored quarks through strongly interacting systems, and their subsequent evolution into color-singlet hadrons, are phenomena that showcase unique facets of Quantum Chromodynamics (QCD). Medium-stimulated gluon…
We review the theoretical interpretation of deep-inelastic electron-proton scattering at low values of the Bjorken variable $x \simeq Q^2/W^2 \lsim 0.1$. The process proceeds via the interaction of quark-antiquark $(q \bar q)$ color-dipole…
We pursue the hypothesis that the events with a large rapidity gap, observed at HERA, reflect the scattering of electrons off lumps of wee partons inside the proton. A simple scaling behaviour is predicted for the diffractive structure…
We formulate the perturbative QCD approach to coherent diffractive dijet production in pion-nucleon and pion-nucleus collisions at high energy. For hard dijets the Pomeron splitting mechanism in which both helicity amplitudes are…
We perform a novel type of analysis of diffractive deep-inelastic scattering data, in which the input parton distributions of the Pomeron are parameterised using the perturbative QCD expressions. In particular, we treat individually the…
On the basis of the experimental data on diffractive processes in $\pi p$, $pp$ and $p \bar p$ collisions at intermediate, moderately high and high energies, we restore the scattering amplitude related to the $t$-channel exchange by vacuum…
In this work we consider the QCD parton saturation models to describe soft interactions at the high energy limit. The total and elastic cross sections as well as the elastic slope parameter are obtained for proton-proton and pion-proton…
The asymptotic collinear factorisation theorem, which holds for diffractive deep-inelastic scattering, has important modifications in the sub-asymptotic HERA regime. We use perturbative QCD to quantify these modifications. The diffractive…
We ask the question whether the quark and gluon distributions in the Pomeron obtained from QCD fits to hard diffraction processes at HERA can be dynamically generated from a state made of ``valence-like'' gluons and sea quarks as input. By…
QCD at the classical level possesses scale invariance which is broken by quantum effects. This ``dimensional transmutation'' phenomenon can be mathematically described by formulating classical gluodynamics in a curved, conformally flat,…
We review the current understanding of heavy quark parton distributions in nucleons and their impact on deep inelastic scattering, collider physics, and other processes at high energies. The determination of the heavy-quark parton…
We explore the deep inelastic structure functions of hadrons nonperturbatively in an inverse power expansion of the light-front energy of the probe in the framework of light-front QCD. We arrive at the general expressions for various…
Quantum Chromodynamics (QCD) is a firmly established part of the Standard Model, yet its long distance properties remain challenging at a conceptual level. In recent years significant experimental and theoretical progress has been made…
Recent measurements of QCD interactions involving large momentum transfers are reviewed. The status of measurements of the strong coupling constant is summarised. Recent developments in the measurement and interpretation of deep inelastic…
We study both polarized and unpolarized proton structure functions in the kinematical region of large Bjorken x and four-momentum transfer of few GeV^2. In this region the phenomenon of parton-hadron duality takes place between the smooth…
We discuss the behaviour of the energy spectrum of particles in jets near the limit of small momenta of a few hundred MeV. In QCD parton cascades the soft gluons are coherently emitted from all faster partons in the jet and their production…
The large rapidity gap events, observed at HERA, have changed considerably our physical picture of deep inelastic scattering during the past years. We review the present theoretical understanding of diffractive DIS with emphasis on the…
We present a formalism for high energy soft processes, mediated by Pomerons, which embodies pion-loop insertions in the Pomeron trajectory, rescattering effects via a two-channel eikonal and high-mass diffractive dissociation. It describes…
An improved understanding of nonperturbative QCD can be obtained by the recently developed soft color interaction models. Their essence is the variation of color string-field topologies, giving a unified description of final states in high…
A phenomenological model of hard diffraction is presented, in which the structure of the Pomeron is derived from the structure of the parent hadron. Predictions for diffractive deep inelastic scattering are compared with data.