Related papers: Physics with two photons at HERA
An overview is given of the ongoing measurement at HERA of the parton structure of the photon, as a function of its virtuality. Preliminary ZEUS results show disagreement with an NLO QCD calculation.
Recent experimental results on the partonic structure of the photon and on the color singlet exchange in strong interaction processes are reviewed. At the LEP electron-positron and HERA lepton-proton colliders, complementary and consistent…
The structure of real and virtual photons has been studied in ep collisions at HERA using dijet production. Measurements of differential dijet cross sections as function of the fraction of photon's momentum invested in the dijet system are…
The operation of HERA with polarized proton and electron beams will allow to study a wide variety of observables in polarized electron-proton collisions at $\sqrt s=300$ GeV. The physics prospects of this project have been elaborated in…
A review is presented of the different theoretical models proposed to approach consistently the interplay between soft and hard physics, that can now be studied experimentally at HERA for the first time.
The physics of peripheral collisions with relativistic heavy ions (PCRHI) is reviewed. One- and two-photon processes are discussed.
A pedagogical introduction to the experimental results on hard photoproduction at HERA is provided. Then the latest results in this field from ZEUS and H1 are reviewed.
Measurements of diffractive phenomena observed at HERA are reviewed. A short introduction to the theoretical background is presented. The review focuses on the current experimental directions and discusses the exclusive production of vector…
We give a pedagogical introduction to hard photoproduction processes at HERA, including the production of jets, hadrons, and prompt photons. Recent theoretical developments in the three areas are reviewed.
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.
Measurements of hadronic final states by H1 and ZEUS at HERA are presented. The H1 measurements consist of measurements of charged particle spectra in deep -inelastic $ep$ scattering and of forward photons and neutrons. The ZEUS results…
The past year has seen a number of important developments in hard photoproduction physics at the HERA Collider. These are surveyed.
The status of the measurements and the theoretical developments concerning the hadronic structure of the photon are briefly summarised.
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at…
We show that the rising total photoproduction cross section recently observed at HERA is entirely consistant with the impact-picture in the theory of expanding protons which was proposed more than twenty years ago. More accurate data, which…
Recent NLO calculations for the photoproduction of one and two jets at HERA are compared to data from H1 and ZEUS. We discuss the physics potential of these measurements for constraining the photon structure, especially the quark density at…
We argue that existing measurements of ep collisions at HERA --in which an energetic photon is made via a QED `Compton' subprocess-- can provide rather detailed information on the photonic parton density of the proton. This function and its…
HERA measurements of diffractive ep scattering - the quasi-elastic scattering of the photon in the proton colour field - are summarised. Emphasis is placed on the most recent data.
I discuss the theoretical understanding of key measurements at HERA and their relevance for physics at LHC, focusing on recent developments for structure functions and for diffraction.
Present data on the partonic content of the photon from LEP, TRISTAN and HERA accelerators are reviewed and the essential aspects of the underlying ideas and methods are pointed out. Results of the unpolarized photon structure function F_2…