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 $\sqrt{s_{\rm NN}}$ = 200~GeV measured with the STAR detector at RHIC. The slope of the $v_1$ rapidity dependence ($dv_{1}/dy$) 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 $dv_{1}/dy$ 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 $\sqrt{s_{\rm NN}}$ = 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.