Leading Charm in Hadron-Nucleus Interactions in the Intrinsic Charm Model

Abstract

Leading charm hadrons produced in hadron-nucleus interactions cannot be adequately described within the parton fusion model. Recent results on charm baryon production in $\Sigma^- A$ interactions at 330 GeV with the WA89 detector disagree with fusion predictions. Intrinsic heavy quark pairs in the $\Sigma^-(dds)$ wavefunction provide a simple mechanism for producing fast charm hadrons. We calculate leading charm baryon production from $\Sigma^-$, $\pi^-$ and $p$ projectiles in a two component model combining parton fusion with intrinsic charm. Final state $D^{-}$, $\Sigma_{c}^{0}$, $\Xi_{c}^{+}$, and $\Lambda_{c}^{+}$ $d\sigma/dx_{F}$ distributions and $D^-/D^+$, $D_s^-/D_s^+$ and $\Lambda_c^+/\bar \Lambda^+_c$ asymmetries are compared to WA89 data. Predictions are made for 650 GeV $\Sigma^- A$ and $\pi^- A$ interactions in the SELEX detector at Fermilab and for 800 GeV $pA$ interactions.