Open charm hadroproduction and the charm content of the proton

We advocate charmed-hadron inclusive hadroproduction as a laboratory to probe intrinsic charm (IC) inside the colliding hadrons. Working at next-to-leading order in the general-mass variable-flavor-number scheme endowed with nonperturbative fragmentation functions recently extracted from a global fit to e⁺e^- annihilation data from KEKB, CESR, and LEP1, we first assess the sensitivity of Tevatron data of D⁰, D⁺, and D*+ inclusive production to the IC parametrizations provided by Pumplin et al. We then argue that similar data from $pp$ collisions at RHIC would have the potential to discriminate between different IC models provided they reach out to sufficiently large values of transverse momentum.