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ψ(2S) 在LHC的Pb-Pb碰撞中的抑制
S Acharya1, D Adamová2, A Adler3
1Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France.
Physical review letters
|February 9, 2024
概括
在ALICE实验中,测量了LHC中与碰撞中的psi(2S) 碳产量. 结果显示,与J/psi相比,psi(2S) 的显著抑制,表明夸克-子等离子体中的charmonium状态行为.
科学领域:
- 高能物理 高能物理
- 核物理 核物理 核物理
- 量子色态动力学 量子色态动力学
背景情况:
- 夸克-子等离子体 (QGP) 是一种在高能核碰撞中产生的物质状态.
- 像J/ψ和 ψ(2S这样的态是QGP属性的敏感探针.
- 了解重离子碰撞中的charmonium抑制,可以了解QGP的形成和演变.
研究的目的:
- 测量大型强子对撞机 (LHC) 中与 (Pb-Pb) 碰撞中 ψ(2S) 状态的产生.
- 作为碰撞中心性和横向动量的函数,研究 ψ(2S) 产量相对于 J/ψ 产量的抑制.
- 将这些测量结果与质子-质子 (pp) 碰撞和理论模型进行比较,以了解QGP中的charmonium行为.
主要方法:
- 利用LHC的ALICE探测器记录Pb-Pb碰撞,每核子-核子对的质量中心能量为5.02TeV.
- 通过其dumion衰变通道测量了 ψ(2S) 炭状态.
- 分析数据以确定包容性生产的截面和比率,包括核修改因子 (R_AA).
主要成果:
- 观察到一个显著的 ψ(2S) 信号,在向前速度 (2.5 < y < 4) 时,横向动量降至零.
- 发现,在中心Pb-Pb碰撞中, ψ(2S) 产量相对于J/ψ被抑制了约2的因子.
- 与pp碰撞相比,pb-Pb碰撞的核修饰因子 (R_AA) 显示在Pb-Pb碰撞中被抑制了高达3的因子.
结论:
- 在Pb-Pb碰撞中强烈抑制 ψ(2S) 提供了其与夸克-子等离子体相互作用的证据.
- 这些发现有助于了解QGP中查解离和再生的机制.
- 结果为完善重离子碰撞和QGP属性的理论模型提供了关键数据.
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