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arXiv 1012.5419hep-exnucl-ex
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用LHC上的ATLAS探测器测量J/Xe产额的中心性依赖关系和观测铅-铅碰撞中的Z产生

Measurement of the centrality dependence of J/ψ yields and observation of Z production in lead-lead collisions with the ATLAS detector at the LHC

The ATLAS Collaboration

摘要:

利用ATLAS探测器,在大型强子对撞机上观察到铅离子碰撞产生的J/π介子产额随中心的抑制。在一个核子-核子质心能量为\surd sNN = 2.76 TeV的最小偏压铅-铅碰撞样本中,对应于约6.7 μ b ^{-1}的积分亮度,J/π介子通过衰变到μ + μ-对而被重建。测得的J/ψ产额,归一化的二元核子-核子碰撞的数量,被发现显着减少从外围到中心的碰撞。的中心依赖性被发现是定性的类似于在以前的,较低的能量实验中观察到的趋势。用相同的样品重建μ + μ-末态的Z玻色子,在66~116 GeV的质量窗口中共选出38个候选粒子。相对Z产量作为中心的函数,也提出了,虽然没有结论可以推断出他们的缩放与二进制碰撞的数量,因为有限的统计。这一分析提供了在LHC铅-铅碰撞中J/Z和Z产生的第一个结果。

英文摘要:

Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of J/ψ mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead-lead collisions at a nucleon-nucleon centre of mass energy \surd sNN = 2.76 TeV, corresponding to an integrated luminosity of about 6.7 μb^{-1}, J/ψ mesons are reconstructed via their decays to μ+μ- pairs. The measured J/ψ yield, normalized to the number of binary nucleon-nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower energy experiments. The same sample is used to reconstruct Z bosons in the μ+μ- final state, and a total of 38 candidates are selected in the mass window of 66 to 116 GeV. The relative Z yields as a function of centrality are also presented, although no conclusion can be inferred about their scaling with the number of binary collisions, because of limited statistics. This analysis provides the first results on J/ψ and Z production in lead-lead collisions at the LHC.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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