Related papers: Resolved Photon Processes
An elementary introduction to the physics of quark-gluon plasma is given. We start with a sketchy presentation of the Quantum Chromodynamics which is the fundamental theory of strong interactions. The structure of hadrons built up of quarks…
The main goals of `spin physics' are recalled, and some theoretical and phenomenological aspects of longitudinally polarized deep inelastic scattering and other hard processes are reviewed. The spin dependent parton densities of protons and…
After giving a very brief introduction to the resolved photon processes, I will summarise the latest experimental information from HERA, on resolved photon contribution to large pt jet production as well as to direct photon production. I…
Latest results on structure functions, as available at the Lepton-Photon Symposium 1999, are presented. This report focusses on three experimental areas: new structure function measurements, in particular from HERA at low x and high Q2;…
We calculate the O(\alpha_s) corrections to the production of a hard and isolated photon accompanied by one or two jets in deep inelastic lepton nucleon scattering at HERA. Numerical results are presented and the potential of this process…
Photons and dileptons are being used to probe the properties of nuclear and quark-gluon matter at high energy densities. This is an area where theory and experiment are driving each other to obtain solid results. However, it is important to…
Two photon collisions offer a variety of physics studies that can be performed at the future electron-positron colliders. Using the planned CEPC parameters as a benchmark we consider several topics to be studied in the two-photon…
We investigate photon emission at the hadronization stage from a quark-gluon plasma created in relativistic heavy-ion collisions. A recombination-model picture suggests that a quark and an antiquark bind into a meson state in hadronization,…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
In the framework of the perturbative QCD we investigate heavy particle mass effects on the unpolarized and polarized photon structure functions, $F_2^\gamma$ and $g_1^\gamma$, respectively. We present our basic formalism to treat heavy…
Two-photon processes in electron-positron collisions of the form $e^+e^-\to e^+e^-X$ are a well-established tool for probing hadronic structure and provide a direct access to non-vector states in $e^+e^-$ collisions. Collisions of quasi…
The production of hard photons in hadronic collisions is studied using Soft-Collinear Effective Theory (SCET). This is the first application of SCET to a physical, observable cross section involving energetic partons in more than two…
A summary is given on the main aspects which were discussed by the working group. They include new results on the deep inelastic scattering structure functions $F_2, xF_3, F_L$ and $F_2^{c\bar{c}}$ and their parametrizations, the…
Photonics, dealing with the generation, manipulation, and detection of photons in various systems, lays the foundation of many advanced technologies. A key task of photonics is to know how photons propagate in complex media such as periodic…
The recent theory developments and latest experimental results on heavy-flavour production in Deep Inelastic Scattering and at hadron colliders are summarized. Models of heavy quarkonia production, non-perturbative corrections to…
Large pT processes at HERA, initiated by almost real and by virtual photons, provide information on the structure of the photon. We report on the latest measurements of dijets and large pT particle production with the H1 detector. This…
Electromagnetic (EM) probes such as photons and dileptons provide direct insight into the space-time evolution of the hot and dense matter formed in heavy-ion collisions. Being unaffected by strong interactions, they serve as penetrating…
We present a model based on a dipole picture with a hard and a soft pomeron in which large dipoles couple to the soft pomeron and small dipoles couple to the hard pomeron. The parameters in the model are fixed by proton-proton scattering…
The collisions of high energy photons produced at an electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions, and extensions of the Standard Model. The luminosity and energy of the colliding…
Direct photon production in association with a heavy quark can serve as an excellent tool for the study of the heavy quark distributions. Currently it is believed that heavy quarks are produced radiatively inside the nucleon, and so there…