Observation of sequential Υ suppression in Au+Au collisions at √ s NN = 200 GeV with the STAR experiment STAR
Observation of sequential Υ suppression in Au+Au collisions at √ s NN = 200 GeV with the STAR experiment STAR
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发表时间：
2022
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通讯作者：
The Star Collaboration
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作者：
The Star Collaboration
本文报道了在相对论重离子对撞机（RHIC）上，用STAR探测器通过双电子和双介子通道测量了√s NN = 200 GeV下Au+Au碰撞的顺序Υ抑制。在0-60%的中心性中，对于Υ（1S）和Υ（2S），量化重离子碰撞与p + p碰撞的产率抑制水平的核修饰因子（R AA）为0。40±0。03（统计）±0。03(系统)。±0。07（范数）和0。26±0。07（统计）±0。02(系统)。±0。在95%置信水平下，Υ（3S） R AA的上限为0.20。这一观察结果提供了实验证据，证明在RHIC中Υ（3S）明显比Υ（1S）受到更大的抑制。Υ（1S）的抑制水平与在大型强子对撞机上观察到的高得多的碰撞能量相当。这些结果表明，在RHIC中创造了一种定义介质，其温度足够高，可以强烈抑制Υ激发态。
We report on measurements of sequential Υ suppression in Au+Au collisions at √ s NN = 200 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the di-electron and di-muon channels. In the 0-60% centrality class, the nuclear modification factors ( R AA ), which quantify the level of yield suppression in heavy-ion collisions compared to p + p collisions, for Υ(1S) and Υ(2S) are 0 . 40 ± 0 . 03 (stat.) ± 0 . 03 (sys.) ± 0 . 07 (norm.) and 0 . 26 ± 0 . 07 (stat.) ± 0 . 02 (sys.) ± 0 . 04 (norm.), respectively, while the upper limit of the Υ(3S) R AA is 0.20 at a 95% confidence level. This observation provides experimental evidence that the Υ(3S) is significantly more suppressed than the Υ(1S) at RHIC. The level of suppression for Υ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a deconfined medium at RHIC whose temperature is sufficiently high to strongly suppress excited Υ states.