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arXiv 2510.03390hep-phnucl-exnucl-th
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首次证明夸克胶子等离子体具有非零分辨长度

First Demonstration that Quark-Gluon Plasma has a Nonzero Resolution Length

Arjun Srinivasan Kudinoor, Daniel Pablos, Krishna Rajagopal

AI总结:

本研究利用 Hybrid Model 联合解释 ALICE 与 ATLAS 喷注子结构及核修正因子数据,排除分辨长度为无穷大和零两种极限,首次证明 QGP 具有约 $(1-2)/(πT)$ 的有限非零分辨长度。

摘要:

我们报告了在 arXiv:2509.08881 中开展的研究,考察近期的喷注子结构测量如何约束重离子碰撞中形成的夸克胶子等离子体的分辨长度 $L_{\rm res}$。$L_{\rm res}$ 的定义是:喷注簇射内的高能部分子被介质分辨,当且仅当它们之间的距离大于 $L_{\rm res}$。利用 Hybrid Model,我们复现了 ALICE 关于 $R=0.2$ 带电粒子喷注的标度化 Soft Drop 角 $θ_g$ 数据,以及 ATLAS 关于由窄的 $R=0.2$ 含次子喷注重新聚类得到的 $R=1$ 喷注的 Hard Group 角 $ΔR_{12}$ 数据。我们发现,ALICE 观测到的 PbPb 碰撞中 $θ_g$ 分布变窄,以及 ATLAS 观测到的 PbPb 碰撞中具有多个窄子喷注的 $R=1$ 喷注受到抑制,排除了 $L_{\rm res}=\infty$;在该极限下,整个部分子簇射如同单个有色物体一样相干地向等离子体损失能量。随后,我们将 Hybrid Model 计算与 ATLAS 对由 $R=0.2$ 子喷注重新聚类得到的 $R=1$ 喷注的 $R_{\rm AA}$ 测量进行比较;该量作为 Soft Drop 角 $dR_{12}$ 的函数,而 $dR_{12}$ 通过整理与每个 $R=1$ 喷注相关联的所有带电粒子径迹获得。我们首次证明,ATLAS 数据与 $L_{\rm res}=0$ 不相容;在该极限下,等离子体会分辨部分子簇射中每一次分裂。当 QGP 具有有限、非零的 $L_{\rm res}\sim(1-2)/(πT)$ 时,我们的结果与数据符合最佳。

英文摘要:

We report on our investigation in arXiv:2509.08881 of how recent jet substructure measurements constrain the resolution length $L_{\rm res}$ of the quark-gluon plasma formed in heavy-ion collisions. $L_{\rm res}$ is defined such that high-energy partons within a jet shower are resolved by the medium if and only if they are separated by a distance greater than $L_{\rm res}$. Using the Hybrid Model, we reproduce ALICE data on the scaled Soft Drop angle $θ_g$ for $R=0.2$ charged-particle jets and ATLAS data on the Hard Group angle $ΔR_{12}$ for $R=1$ jets reclustered from skinny $R = 0.2$ inclusive subjets. We find that the narrowing of the $θ_g$-distribution in PbPb collisions observed by ALICE and the suppression of $R=1$ jets with multiple skinny subjets in PbPb collisions observed by ATLAS rule out $L_{\rm res} = \infty$, where each entire parton shower loses energy to the plasma coherently as if it were a single colored object. We then compare Hybrid Model calculations to ATLAS measurements of $R_{\rm AA}$ of $R=1$ jets reclustered from $R=0.2$ subjets, as a function of the Soft Drop angle $dR_{12}$ obtained by grooming all charged-particle tracks associated with each $R=1$ jet. We demonstrate, for the first time, that the ATLAS data is inconsistent with $L_{\rm res} = 0$, where the plasma resolves every splitting in a parton shower. Our results agree best with the data when QGP possesses a finite, nonzero $L_{\rm res}\sim (1-2)/(πT)$.

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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