QCD and Intrinsic Heavy Quark Predictions for Leading Charm and Beauty Hadroproduction

Recent experiments at Fermilab and CERN have observed a strong asymmetry between the hadroproduction cross sections of leading D mesons, containing projectile valence quarks, and nonleading charmed mesons, without projectile valence quarks. The observed correlations of the πN → DX cross section with the projectile charge violates the usual assumption that heavy quark jet fragmentation factorizes. We examine the asymmetry between leading and nonleading charm production as a function of xf and p 2 T assuming a two-component model combining leading-twist fusion subprocesses and charm production from intrinsic heavy quark Fock states. We predict a sizable asymmetry at low pT and high xf from coalescence of the charm quarks with the comoving spectator quarks of the projectile. An intrinsic cc production cross section of 0.5 μb is sufficient to explain both the magnitude and kinematic dependence of the asymmetry. In contrast, the charm jet hadronization mechanisms contained in PYTHIA predict a sizeable leading charm asymmetry even at low xF . The two-component model is extended to predict the asymmetry in B meson production in proton-proton and pion-proton interactions.