Upsilon Productions at STAR
نویسنده
چکیده
The Υ(1S + 2S + 3S) → ee cross section is measured at mid-rapidity (y) in p + p collisions and in d+Au collisions at center-of-mass energy √ s = 200 GeV with the STAR detector at RHIC. In p + p, the measured cross section is found to be consistent with the world data trend as a function of √ s, in agreement with the Color Evaportaion Model (CEM), and underestimated by the Color Singlet Model (CSM) up to the Next-to-LeadingOrder Quantum Chromodynamics (NLO QCD) calculations. In d+Au, the measured cross section is in agreement with the CEM prediction with anti-shadowing effects, and the nuclear modification factor indicates that Υ(1S+2S+3S) production follows binary scaling within the current uncertainties. These measurements provide a benchmark for the future measurements of Υ production in Au+ Au collisions.
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