Observation of $D^0$ meson nuclear modifications in Au+Au collisions at   $\sqrt{s_{_{\mathrm{NN}}}}$ = 200 GeV
  We report the first measurement of charmed-hadron ($D^0$) production via the hadronic decay channel ($D^0\rightarrow K^- + \pi^+$) 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. 
L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed,   I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. A...
nucl-ex