D meson relative yield in hadronic collisions

The smallness of the c quark ''sea'' in usual hadrons results in the necessity to consider double-gluon production of charm. In the case of D mesons it corresponds to the production of small invariant masses of the DD pair and dominance of two first partial waves of c anti c quarks. The smallness of interaction, that leads to hyperfine spallation of D-D * results in the fact that the cross section for D * production is considerably larger than that for D, i.e. sigma (D * anti D *) > > sigma (D anti D)