Diphoton production at the Tevatron in the quasi-multi-Regge-kinematic approach

We study the production of prompt diphotons in the central region of rapidity within the framework of the quasi-multi-Regge-kinematic approach applying the hypothesis of quark and gluon Reggeization. We describe accurately and without free parameters the experimental data which were obtained by the CDF Collaboration at the Tevatron collider. It is shown that the main contribution to the studied process is given by the direct fusion of two Reggeized gluons into a photon pair, which is described by the effective Reggeon-Reggeon to particle-particle vertex. The contribution from the annihilation of Reggeized quark-antiquark pair into a diphoton is also considered. At the stage of numerical calculations we use the Kimber-Martin-Ryskin prescription for unintegrated quark and gluon distribution functions, with the Martin-Roberts-Stirling-Thorne collinear-parton densities for a proton as input.