Observation of $D^0$ meson nuclear modifications in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 200 GeV

Abstract

We report the first measurement of charmed-hadron ($D^0$) production via the hadronic decay channel ($D^0\to K^{-}+\ddot{I}{€}^{+}$) in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 200\,GeV with the STAR experiment. The charm production cross-section per nucleon-nucleon collision at mid-rapidity scales with the number of binary collisions, $N_{bin}$, from $p$+$p$ to central Au+Au collisions. The $D^0$ meson yields in central Au+Au collisions are strongly suppressed compared to those in $p$+$p$ scaled by $N_{bin}$, for transverse momenta $p_T>3$ GeV/$c$, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate $p_T$ is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

7 pages including author list, 4 figures, submit to PRL with revised version