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arXiv 1609.06643nucl-exhep-ex
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$\sqrt{s_{\rm NN}}$ = 2.76 TeV的Pb-Pb碰撞近侧喷流峰形的异常演化

Anomalous evolution of the near-side jet peak shape in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

ALICE Collaboration

摘要:

两粒子角关联的测量是研究$p_{\mathrm{T}}$区域喷流猝灭的有力工具,而直接喷流识别是无法实现的。在这些测量中,赝快度($Δη$)和方位角($Δφ$)差用于提取由与较高$p_{\mathrm{T}}$触发粒子($1 < p_{\mathrm{T, trig}} <$ 8 GeV/c)相关联的粒子形成的近侧峰的形状。的近侧峰和远程相关的组合拟合应用到数据允许提取的中心性演化的峰值形状在$\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV的铅铅碰撞。从外围到中心碰撞发现,在低$p_{\mathrm{T}}$时,$Δη$方向上的峰显著加宽,其在4 GeV/c以上消失,而在$Δφ$方向上的峰几乎与中心性无关。对于10%的最中心碰撞和$1 < p_{\mathrm{T, assoc}} <$ 2 GeV/c,$1 < p_{\mathrm{T, trig}} <$ 3 GeV/c,观察到一个新的特征:在峰的中心附近出现耗尽。结果进行了比较,PP碰撞在同一中心的质量能量和AMPT模型模拟。研究模型的比较表明,扩大和发展的耗尽连接到径向和纵向流的强度。

英文摘要:

The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a $p_{\mathrm{T}}$ region inaccessible by direct jet identification. In these measurements pseudorapidity ($Δη$) and azimuthal ($Δφ$) differences are used to extract the shape of the near-side peak formed by particles associated to a higher $p_{\mathrm{T}}$ trigger particle ($1 < p_{\mathrm{T, trig}} <$ 8 GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV. A significant broadening of the peak in the $Δη$ direction at low $p_{\mathrm{T}}$ is found from peripheral to central collisions, which vanishes above 4 GeV/c, while in the $Δφ$ direction the peak is almost independent of centrality. For the 10% most central collisions and $1 < p_{\mathrm{T, assoc}} <$ 2 GeV/c, $1 < p_{\mathrm{T, trig}} <$ 3 GeV/c a novel feature is observed: a depletion develops around the centre of the peak. The results are compared to pp collisions at the same centre of mass energy and to AMPT model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow.

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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