Relevance of the quark component in prompt photon and electroweak gauge boson production at high energies

In the framework of the kT-factorization approach, we study the production of prompt photons and electroweak gauge bosons in high energy proton-(anti)proton collisions at modern colliders. Our consideration is based on the amplitude for the production of a single photon or W±/Z0 boson associated with a quark pair in the fusion of two off-shell gluons. The quark component is taken into account separately using the quark-gluon scattering and quark-antiquark annihilation QCD subprocesses. Special attention is put on the contributions from the quarks involved into the earlier steps of the evolution cascade. Using the Kimber-Martin-Ryskin formalism, we simulate this component and demonstrate that it plays an important role at both the Tevatron and LHC energies. Our theoretical results are compared with recent experimental data taken by the D diameter and CDF collaborations at the Tevatron. (orig.)