Charmed hadron asymmetries in the intrinsic charm coalescence model Original Research Article

Fermilab experiment E791, measuring charmed hadron production in π−A interactions at 500 GeV with high statistics, has observed a strong asymmetry between the hadroproduction cross sections for leading D mesons which contain projectile valence quarks and the non-leading charmed mesons without projectile valence quarks. Such correlations of the charge of the D meson with the quantum numbers of the beam hadron explicitly contradict the factorization theorem in perturbative QCD which predicts that heavy quarks hadronize through a jet fragmentation function that is independent of the initial state. The E791 experiment also measures Λc/Λc and Ds/Ds production asymmetries as well as asymmetries in DD pair production. We examine these asymmetries and the fractional longitudinal momentum, xF, distributions for single and pairs of charmed hadrons within a two-component model combining leading-twist gg and qq fusion sub-processes with charm production from intrinsic heavy quark Fock states. A key feature of this analysis is intrinsic charm coalescence, the process by which a charmed quark in the projectileʹs Fock state wave function forms charmed hadrons by combining with valence quarks of similar rapidities.