Related papers: Real and virtual photon structure from dijet event…
The status of measurements and interpretation of the proton structure function F2 is summarized. The measurements are subjected to DGLAP fits, from which the gluon density is extracted and a comparison to measurements of F2c is performed.…
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…
The triple-differential dijet cross-section, d^3 sigma_{ep}/dQ2 dE_t2 dxgjets, is measured with the H1 detector at HERA as a function of the photon virtuality Q^2, the fraction of the photon's momentum carried by the parton entering the…
Real or virtual photons are excellent probes of nuclear structure, with a strong sensitivity to gluon distributions. Photonic reactions can be studied using ultra-peripheral collisions or at an electron-ion collider. Final states like…
The hadronic interactions of the photon are studied in terms of new measurements of the total hadronic cross section and di-jet production in photon-photon collisions at LEP2.
This review covers selected results from the LEP experiments on the structure of quasi-real and virtual photons. The topics discussed are the total hadronic cross-section for photon-photon scattering, hadron production, jet cross-sections,…
Measurements of the structure of the virtual photon in the transition region between quasi-real photons and those far from mass-shell have been made with the ZEUS detector at HERA, using an integrated luminosity of 38pb-1. Dijet final…
The structure of the photon is studied in photon-photon collisions at LEP. New measurements have become available exploring the structure function F2g of the photon to the lowest values of x yet, where the hadronic component of the photon…
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 present status of the measurements of hadronic structure functions of the photon, investigated in deep inelastic electron-photon scattering at LEP, is presented. This article covers the hadronic structure function F_2^gamma of…
We review next-to-leading order calculations of one- and two-jet production in ep collisions at HERA for photon virtualities in the range 1<Q^2<100 GeV^2. Soft and collinear singularities are extracted using the phase space slicing method.…
New results reported at the Moriond-QCD 2003 conference from the experiments ALEPH, DELPHI, L3, and OPAL on the structure of the photon as well as heavy quark production in gammagamma collisions are presented. The hadronic structure of the…
A future Electron Ion Collider (EIC) will be able to provide collisions of polarized electrons with protons and heavy ions over a wide range of center-of-mass energies (20 $\mathrm{GeV}$ to 140 $\mathrm{GeV}$) at an instanteous luminosity…
The structure functions of real and virtual photons are derived from cross section measurements of the reaction e^+e^ -> e^+e^- + hadrons at LEP. The reaction is studied at \sqrt{s} ~ 91 GeV with the L3 detector. One of the final state…
The feasibility of an experimental determination of the parton distributions of virtual photons at high energy $ep$ colliders is studied in the context of the DESY-HERA collider. Recently proposed parton densities of virtual photons are…
The dependence of dijet production on the virtuality of the exchanged photon, Q^2, has been studied by measuring dijet cross sections in the range 0 < Q^2 < 2000 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 38.6…
The dependence of the photon structure on the photon virtuality, Q^2, is studied by measuring the reaction e^+p\to e^+ + {\rm jet} + {\rm jet} + {\rm X} at photon-proton centre-of-mass energies 134 < W < 223 GeV. Events have been selected…
In the first part of this paper we assess the possibility of observing the gluon distribution in a real photon by measuring the photoproduction cross section of large-pt photons. In the second part we calculate the virtual photoproduction…
Measurements sensitive to the structure of both real and virtual photons are presented and compared to theoretical models with various photon parton distribution functions (PDFs). Measurements for real photons show a tendency for the…
Highly energetic jets and photons are complementary probes for the kinematics and the topology of nuclear collisions. Jets are collimated sprays of charged and neutral particles, which are produced in the fragmentation of hard scattered…