Related papers: Jet Photoproduction
We study the diffractive production of high pt photons at HERA. We have implemented the process as a new hard sub-process in the HERWIG event generator in order to prepare the ground for a future measurement.
The production of prompt photons in photoproduction reactions in the ZEUS experiment is discussed. Cross sections for inclusive prompt photons and for prompt photons accompanied by jets are compared with theory, and the latter are used to…
A formalism is developed for the partial wave analysis of data on meson photoproduction off deuterons and applied to photoproduction of $\eta$ and $\pi^0$ mesons. Different interpretations of a dip-bump structure of the $\eta$…
We compare the BFKL prediction for the associated production of forward jets at HERA with fixed-order matrix element calculations taking into account the kinematical cuts imposed by experimental conditions. Comparison with H1 data of the…
We study the photoproduction of an isolated photon and a jet based on a code of partonic event generator type which includes the full set of next-to-leading order corrections. We compare our results to a recent ZEUS analysis in which an…
The cross section for the photoproduction of events containing three jets with a three-jet invariant mass of M_3J > 50 GeV has been measured with the ZEUS detector at HERA. The three-jet angular distributions are inconsistent with a uniform…
We study photoproduction of jets and heavy flavors in a polarized collider mode of HERA and in polarized $ep$ collisions at $\sqrt{S}\approx 30$ GeV. We examine the sensitivity of the cross sections and their asymmetries to the proton's…
We investigate in detail the effect of a direct pomeron coupling to quarks on the production of jets in $ep$ scattering with almost real photons. Jet production via a direct pomeron coupling is compared with the resolved--pomeron mechanism.…
A search for photoproduction events which contain a rapidity gap between the two highest transverse energy jets has been conducted at HERA using the ZEUS detector. The jets have transverse energies greater than 6~GeV, and are separated by…
Recent results from HERA are presented. The main reviewed subjects are polarized DIS cross sections, parton density determination, diffractive PDFs, multi-jet production and searches for physics beyond the Standard Model.
Inelastic and diffractive production of J/psi mesons at HERA is reviewed. The data on inelastic photoproduction are described well within errors by the Colour Singlet Model in next-to-leading order. A search for colour octet processes…
We show that the recent measurements of the total photoproduction cross section at HERA energies [1] are in agreement with our earlier prediction based on high-energy hadronic structure of the photon in the QCD minijet-type model [2]. We…
Inclusive jet production in neutral and charged current deep inelastic scattering, in photoproduction and the transition region has been studied with the ZEUS and H1 detectors at HERA. The measurements have been compared to…
An overview of experimental results on searches for new phenomena at HERA is presented. The complementarity with searches performed at other experiments is discussed and the prospects for a discovery, using the full HERA data to be…
Measurements of inclusive jet and dijet cross sections in photoproduction and deep inelastic scattering are presented. These measurements provide new tests of QCD, constrain the parton densities of the proton and the photon, and allow the…
Jet photoproduction, where the two highest transverse energy ($\ETJ$) jets have $\ETJ$ above 6 GeV and a jet-jet invariant mass above 23~GeV, has been studied with the ZEUS detector at the HERA $ep$ collider. Resolved and direct…
Highlights selected from recent measurements of colour-singlet exchange processes at HERA are summarised. Particular emphasis is placed on energy and momentum transfer dependences and the decomposition of the data into an expansion in Regge…
Heavy quarks are copiously produced in two-photon collisions at $e^+e^-$ colliders. The theoretical predictions including QCD radiative corrections are compared to recent experimental data on $\gamma\gamma$ production of charm quarks at…
I present a small selection of the many QCD studies that have been performed at HERA. I concentrate on results that have been made available in the past year. Results are presented on the QCD description of the parton density functions,…
Recent data obtained in ep collisions at HERA by the H1 collaboration are presented: searches for new phenomena beyond the Standard Model, measurement of the inclusive neutral and charged current cross sections and of the proton structure…