  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 $\pi^{\pm} N \to D^\pm X$
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 $x_f$ and $p_T^2$
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 $p_T^2$ and high $x_f$ from coalescence of the charm quarks
with the comoving spectator quarks of the projectile. An intrinsic $c \overline
c$ production cross section of 0.5 $\mu$b 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 $x_F.$ The two-component model is extended to predict the
asymmetry in $B$ meson production in proton-proton and pion-proton
interactions.
