D+- and D0 (anti D0) production asymetries in pion-proton collisions

We use a two-component model to describe the production mechanism of D mesons in pi-p collisions. The model combines the usual QCD processes plus fragmentation and recombination of charm that has been produced by nonperturbative QCD mechanisms. A hard charm component in the pion must be responsible of the particle anti-particle production asymmetries observed.