Open charm production in relativistic nucleus–nucleus collisions Original Research Article

We calculate excitation functions for open charm mesons in Au+Au reactions from AGS to RHIC energies within the HSD transport approach which is based on string, quark, diquark View the MathML source and hadronic degrees of freedom. The open charm cross sections from pN and πN reactions are fitted to results from PYTHIA and scaled in magnitude to the available experimental data. From our dynamical calculations we find an approximate View the MathML source-scaling for pions, kaons, D mesons and J/Ψ — when discarding final-state elastic scattering of kaons and φ mesons with pions — in central collisions of Au+Au at 160 AGeV (with an apparent slope of 176 MeV) without employing the assumption of a Quark–Gluon Plasma (QGP). We demonstrate that this result is essentially due to a relative View the MathML source-scaling in pp collisions at View the MathML source GeV. At lower bombarding energies of 25 AGeV a suppression of D mesons by a factor of ∼10 relative to a global View the MathML source-scaling with slope 143 MeV is expected. However, when incorporating attractive D-meson self-energies as suggested by QCD sum rules, an approximate View the MathML source-scaling is regained even at 25 AGeV. The effects of D-meson rescattering and charmonium absorption are discussed, furthermore, with respect to rapidity and transverse mass distributions in central collisions of Au+Au at 25, 160 AGeV and 21.3 ATeV.