We calculate medium photons due to Compton and annihilation processes in an anisotropic media. The effects of time-dependent momentum-space anisotropy of Quark-Gluon-Plasma (QGP) on the medium photon production are discussed. Such an anisotropy can results from the initial rapid longitudinal expansion of the matter, created in relativistic heavy ion collisions. A phenomenological model for the ...

We calculate medium photons due to Compton and annihilation processes in an anisotropic media. The effects of time-dependent momentum-space anisotropy of Quark-Gluon-Plasma (QGP) on the medium photon production are discussed. Such an anisotropy can results from the initial rapid longitudinal expansion of the matter, created in relativistic heavy ion collisions. A phenomenological model for the ...

High energy multiparticle photoproduction off nuclear targets is studied. The photon is assumed to interact in direct scattering processes or as a resolved qq̄-state according to the Generalized Vector Dominance Model. In the description of resolved interactions multiple soft and hard processes in each qq̄–nucleon interaction are taken into consideration. The model, formulated within the framewor...

We provide complete analytic expressions for the isolated prompt photon production cross section in e+e− annihilation reactions through one-loop order in quantum chromodynamics (QCD) perturbation theory. Functional dependences on the isolation cone size δ and isolation energy parameter are derived. The energy dependence as well as the full angular dependence of the cross section on θγ are displ...

The rich structure of photon-exchange processes at hadron colliders is studied. We discuss central vector meson production (pp → p + J/ψ + p), W production (pp → p+W+X) and μ+μ− production. Each process has distinct, and large, soft pp rescattering effects, which can be directly observed by detecting the outgoing protons. This allows a probe of the optical density of the proton, which plays a c...

Heavy quark and direct photon production in hadronic collisions are processes of great interest. The discovery of the top has increased efforts in the calculation of heavy quark production cross sections while direct photon production is important for determinations of gluon distributions. Near threshold for the production of the final state in these processes one can resum logarithmic correcti...