Related papers: Particle production and saturation at HERA
A brief survey is given of recent HERA results in jet production and prompt photon production, together with the evaluation of the QCD coupling constant alpha_s.
Future prospects of hard diffraction at HERA a reviewed. A selection of processes which can be calculated in pQCD is given, with emphasis on the separation of soft and hard diffraction. The main focus will be put on the energy dependence of…
HERA data on soft hadron production are discussed. The measured inclusive and exclusive hadron cross sections show a simple scaling behaviour.
The parton momentum densities in the proton are obtained from a NLO QCD analysis of structure functions measured by HERA and fixed target experiments. The uncertainties in these parton densities, the structure functions and related cross…
The cross section for dijet photoproduction at high transverse energies is presented as a function of the transverse energies and the pseudorapidities of the jets. The measurement is performed using a sample of ep-interactions corresponding…
The electron-proton collider HERA allows the study of the partonic content of the proton in regions of Q-squared up to 50,000 GeV$^2$ and values of Bjorken-x down to 10^-5. This paper presents recent precision measurements of structure…
We present a simplified approach enforcing energy conservation to incorporate the effects of zonal modes alongside wave-particle nonlinearities in the determination of the saturation amplitude. The model assumes that the zonal perturbations…
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…
Recent measurements of diffractive vector-meson production with the general-purpose detectors H1 and ZEUS in electron-proton interactions with 300 GeV center-of-mass energy at the HERA accelerator complex have stimulated great interest in…
The ultrahigh energy neutrino cross section is reviewed. Experimental results from HERA electron-proton and positron-proton scattering have yielded new information about the small x behavior of the parton distribution functions. We compare…
The perturbative QCD approach to multiparticle production assuming Local Parton Hadron Duality (LPHD) and some recent results are discussed. Finite asymptotic scaling limits are obtained for various observables, after an appropriate…
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 parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and…
We revisit the "`hybrid formalism"' for particle production used recently to study saturation effects in single hadron multiplicities at forward rapidities at RHIC and LHC. We point out that at leading twist there is an extra contribution…
Attempts to understand the recent observation of an excess of events in the neutral and charged current channels at high$-Q^2$ at HERA has provided an excellent example of how experiments at both low and high energies can be used to…
A selection of theoretical and experimental results are presented in the broader context of understanding QCD and its relation to photon physics. A phenomenological analysis of HERA data to constrain the gluon content of the proton and…
The cross section for bottom quark production at fixed-target energies is calculated for a wide range of beam momenta. A detailed analysis is given for the HERA-B experiment. We consider both the order $\alpha_s^3$ cross section and the…
An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo…
Scattering amplitudes in quantum field theories are of widespread interest, due to a large number of theoretical and phenomenological applications. Much is known about the possible behaviour of amplitudes, that is independent of the details…
The prospects of physics beyond the standard model in deep inelastic scattering are reviewed, emphasizing some scenarios which attained attention after the observation of an excess of events with large momentum transfer at HERA.