Nuclear Modification Factor of $D^0$ Meson in Au+Au Collisions at   $\sqrt{s_{NN}}$ = 200 GeV
  Heavy-flavor quarks are dominantly produced in initial hard scattering processes and experience the whole evolution of the system in heavy-ion collisions at RHIC energies. Thus they are suggested to be an excellent probe to the medium properties through their interaction with the medium. In this proceedings, we report our first measurement of $D^0$ production via topological reconstruction using STAR's recently installed Heavy Flavor Tracker (HFT). We also report our new measurement of Nuclear Modification Factor ($R_{AA}$) of $D^0$ mesons in central Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV as a function of transverse momentum ($p_{T}$). New results confirm the strong suppression at high $p_{T}$ with a much improved precision, and show that the $R_{AA}$ at high $p_{T}$ are comparable with light hadrons ($\pi$) and with D meson measurements at the LHC. Furthermore, several theoretical calculations are compared to our data, and with charm diffusion coefficient 2${\pi}TD_{S}$ $\sim$ 2-12 can reproduce both the $D^0$ $R_{AA}$ and $v_2$ data in Au+Au collisions at RHIC. 
Guannan Xie (STAR collaboration)
nucl-ex hep-ex