Related papers: The Structure of the Virtual Photon
Forward differential cross-section for diffraction dissociation of virtual photons on nucleon target is calculated in the QCD dipole picture. The numerical estimates are presented and discussed.
Photoproduction of jets at HERA provides information on the partonic structure of the photon. We report on the latest dijet photoproduction results, for real photons and for photons at low virtualities, measured with the ZEUS detector.
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…
Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame…
Interactions of virtual photons are analyzed in terms of photon structure. It is argued that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. The…
The QCD treatment of the parton structure of virtual photons is briefly recalled, and possible limitations and open questions are pointed out. Various models for these densities are compared, completed by a short discussion of the treatment…
The photon structure function is a useful testing ground for QCD. It is perturbatively computable apart from a contribution from what is usually called the hadronic component of the photon. There have been many proposals for this…
Preliminary results are presented from a study of dijet photoproduction in ep collisions with both virtual and quasi-real photons at the ZEUS detector. Samples of events with photons of virtuality $P^2$ in the ranges $0.1 < P^2 < 0.55$…
Inclusive jet cross sections in photoproduction for events containing a $D^*$ meson have been measured with the ZEUS detector at HERA using an integrated luminosity of $78.6 {\rm pb}^{-1}$. The events were required to have a virtuality of…
Interactions of virtual photons are analyzed in terms of their parton distribution functions. It is shown that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photonds involved in hard…
This review covers the measurements of the QED and QCD structure of quasi-real and virtual photons from the reaction ee --> ee gamma* gamma(*) --> ee X.
Recent results from ZEUS for inclusive jet cross sections, dijet cross sections and dijet angular distributions are compared with NLO perturbative QCD calculations. The observation of isolated high $P_T$ photons (prompt photons) is also…
Development of concepts related to the photon and its high energy hadronic interaction is briefly reviewed. A photon considered as an ideal probe of hadron structure, paradoxically is also considered as an ideal target to test the…
Measurements of the QED structure of the photon based on the reaction ee --> ee \gamma(*)(P^2)\gamma*(Q^2) --> ee mumu are discussed. This review is an update of the discussion of the results on the QED structure of the photon presented in…
Deeply virtual Compton scattering has been measured in e^+p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb^-1. Cross sections are presented as a function of the photon virtuality, Q^2, and photon-proton…
Measurements of Deeply Virtual Compton Scattering (DVCS) are presented using data collected by the H1 and ZEUS experiments at HERA. The transition from a virtual photon to an on-shell particle is expected to necessitate the use of skewed…
Some aspects of extracting the information on the structure of virtual photons from jet production in ep and e^+e^- collisions are discussed.
Differential dijet cross sections have been measured with the ZEUS detector for photoproduction events in which the hadronic final state containing the jets is separated with respect to the outgoing proton direction by a large rapidity gap.…
The latest results of the ZEUS collaboration on the high Q2, the exchanged boson virtuality, high Bjorken x region up to values of x = 1 are presented. Differential cross sections in x and Q2 are given for Q2 > 725 GeV2. An improved…
A recent H1 measurement of triple differential dijet cross sections in electron-proton interactions in the region of photon virtualities 2<Q2<80 GeV is presented and compared to LO and NLO QCD predictions. Effects that go beyond the…