Heavy quark hadroproduction: NLO qcd (collinear approximation and beyond it) vs. experimental data

Abstract

Abstract We give a short review of theoretical and experimental status of heavy quark production in high energy hadron collisions. The theoretical assumptions and simplifications using in the calculations are discussed. It is shown that in the case of total cross sections and one-particle distributions the conventional NLO parton model (and even LO parton model) with the collinear approximation is enough for the data description. On the other hand, in the case of two-particle correlations (say, the azimuthal correlations of heavy quarks) the collinear approximation has failed, and it is necessary to account for the transverse momenta of initial partons for the description of the data. The different possibilities to do this are discussed, including kT kick and semihard theory.