ϒ production in p+p, d+Au, Au+Au collisions at <math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll" class="math"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn><mspace width="0.25em"></mspace><mtext>GeV</mtext></math> in STAR

Quarkonium is a good probe of the dense matter produced in heavy-ion collisions at RHIC because it is produced early in the collision and the production is theorized to be suppressed due to the Debye color screening of the potential between the heavy quarks. A model dependent measurement of the temperature of the Quark Gluon Plasma (QGP) can be made by examining the ratio of the production of various quarkonium states in heavy ion collisions versus p+p collisions as lattice calculations indicate that the quarkonium states will be sequentially suppressed. Suppression is quantified by calculating R A A , which is the ratio of the yield in Au+Au to the production in p+p scaled by the number of binary collisions. The ϒ states are of particular interest because at 200 GeV the effects of feed down and co-movers are smaller than for J / ψ which decreases the systematic uncertainty of the R A A determination. In addition to hadronic absorption, additional cold nuclear matter effects, such as shadowing of the PDFs, can be determined from d+Au collisions. We will present our results for mid-rapidity ϒ production in p+p, as well as our preliminary results in d+Au and Au+Au at s = 200 GeV . These results will then be compared with theoretical QCD calculations.

夸克偶素是研究相对论重离子对撞机（RHIC）中重离子碰撞产生的致密物质的良好探针，因为它在碰撞早期产生，并且理论上由于重夸克之间势能的德拜色屏蔽，其产生会受到抑制。通过研究重离子碰撞与质子 - 质子碰撞中各种夸克偶素态产生的比率，可以进行依赖于模型的夸克胶子等离子体（QGP）温度测量，因为晶格计算表明夸克偶素态将依次受到抑制。抑制程度通过计算$R_{AA}$来量化，$R_{AA}$是金 - 金碰撞中的产额与质子 - 质子碰撞中产额之比，并根据二元碰撞次数进行了标度。$\Upsilon$态特别令人感兴趣，因为在200 GeV时，级联衰变和伴子的影响比$J/\psi$要小，这降低了$R_{AA}$测定的系统不确定性。除了强子吸收外，从氘 - 金碰撞中还可以确定其他冷核物质效应，例如部分子分布函数（PDFs）的遮蔽。我们将展示质子 - 质子碰撞中中快度$\Upsilon$产生的结果，以及$\sqrt{s}=200$GeV时氘 - 金和金 - 金碰撞的初步结果。然后将这些结果与量子色动力学（QCD）理论计算进行比较。