Upsilon production in d+Au collisions at STAR

Understand

We present the analysis of $\Upsilon\to e^{+}e^{-}$ production in d+Au collisions at $\sqrt{s_{NN}} = 200$ GeV from the STAR experiment.

• Using higher level dedicated $\Upsilon$ triggers, STAR has sampled 32 nb$^{-1}$ of integrated luminosity in year 2008 d+Au run.
• The cross section is found as $BR\times{({{d\sigma}\over{dy}})}_{y=0}^{\Upsilon(1S+2S+3S)}=35\pm4(stat.)\pm5(sys.)$ nb and it is consistent with NLO CEM prediction with anti-shadowing effects.
• In addition we calculated the nuclear modification factor $R_{dAu}=0.98\pm0.32(stat.)\pm0.28(sys.)$, which suggests the $\Upsilon(1S+2S+3S)$ production follows $N_{bin}$ scaling.