Measurements of directed and elliptic flow for $D^0$ and $\overline{D^0}$ mesons using the STAR detector at RHIC

Abstract

We report on the first evidence for a non-zero rapidity-odd directed flow ($v_1$) for $D^0$ and $\overline{D^0}$ mesons in 10-80\% centrality Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200~GeV measured with the STAR detector at RHIC. The slope of the $v_1$ rapidity dependence ($d{v}_1/dy$) averaged over $D^0$ and $\overline{D^0}$ mesons is -0.081 $\pm$ 0.021 $\pm$ 0.017, while that of charged kaons is -0.0030 $\pm$ 0.0001 $\pm$ 0.0002, suggesting significantly larger slope for the $D^0$ mesons. Models indicate that the large $d{v}_1/dy$ of $D^0$ mesons is sensitive to the initially tilted source. We also present a new measurement of the $D^0$ meson elliptic flow ($v_2$) as a function of transverse momentum ($p_T$) in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200~GeV with an improved precision with respect to the previously published results.The $D^0$ $v_2$ results are compared to those of light-flavor hadrons to test the number-of-constituent-quark (NCQ) scaling. Both the $v_1$ and $v_2$ results are compared to recent hydrodynamic and transport model calculations.

Comments: 4 pages, 4 figures. Submitted in Quark Matter 2018 proceedings (accepted for publication in Nuclear Physics A)