Open Charm Yields in 200 GeV p+p and d+Au Collisions at RHIC
  Open charm spectra at mid-rapidity from direct reconstruction of $D^{0}\to K\pi$ and indirect electron/positron measurements via charm semileptonic decay in p+p and d+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV are reported. The combined spectra cover open charm transverse momentum range $0.1{}^{<}_{\sim}p_{T}{}^{<}_{\sim}6$ GeV/$c$. The electron spectra show approximate binary scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon interaction at mid-rapidity for open charm production at RHIC is $d\sigma^{NN}_{c\bar{c}}/dy$=0.31$\pm$0.04(stat.)$\pm$0.08(syst.) mb. The next-to-leading-order pQCD calculation underpredicts the charm yields. 
Lijuan Ruan (for the STAR Collaboration)