论文标题
用Atlas检测器在5.02 TEV处的Pb+Pb碰撞中的子结构依赖性喷射抑制的测量
Measurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector
论文作者
论文摘要
大型强制碰撞器的地图集检测器已用于测量核子 - 核中心质量中心$ \ sqrt {s _ {_ \ mathrm {_ \ Mathrm {nn}}}} = 5.02〜 \ cillivision $ collision $ colponision $ c $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp $ pp比较$ \ sqrt {s} = 5.02〜 \ mathrm {tev} $。 2018年收集的PB+PB数据的集成光度为$ 1.72〜 \ MATHRM {NB^{ - 1}} $，而2017年收集的$ PP $数据的集成发光度为$ 260〜 \ Mathrm {Pb}^{ - 1} $。使用抗$ k_ {t} $算法将其用于此分析中使用的喷气机以RADIUS参数$ r = 0.4 $进行聚类。通过跟踪和热量计信息所定义的喷气组成部分用于确定第一个硬分裂的角度尺度$ r_ \ mathrm {g} $，通过使用Cambridge-aachen算法重新集群来确定它们在喷气机内部的第一个硬拆分，并采用软性美容技术。用于表征PB+PB碰撞中喷气抑制作用的核修饰因子，$ r_ \ mathrm {aa} $，以$ r_ \ mathrm {g} $，喷气横向动量和碰撞中心性的间隔差异地呈现。观察到$ r_ \ mathrm {aa} $ value显着取决于jet $ r_ \ mathrm {g} $。发现以最大测量的$ r_ \ mathrm {g} $产生的喷气机被发现是中央pb+pb碰撞中最小$ r_ \ mathrm {g} $的喷射。 $ r_ \ mathrm {aa} $ values在任何一个$ r_ \ mathrm {g} $ Intervals中的JET $ P_ \ MATHRM {t} $都不会表现出强烈的变化。 $ r_ \ mathrm {g} $和$ p_ \ mathrm {t} $依赖性$ r_ \ mathrm {aa} $在质量上与与连贯性产生的喷气淬火图片相一致，并提供了对这种方法的最直接证据。
The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon-nucleon center-of-mass energy $\sqrt{s_{_\mathrm{NN}}}=5.02~\mathrm{TeV}$ in comparison with $pp$ collisions at $\sqrt{s}=5.02~\mathrm{TeV}$. The Pb+Pb data, collected in 2018, have an integrated luminosity of $1.72~\mathrm{nb^{-1}}$, while the $pp$ data, collected in 2017, have an integrated luminosity of $260~\mathrm{pb}^{-1}$. Jets used in this analysis are clustered using the anti-$k_{t}$ algorithm with a radius parameter $R=0.4$. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale $r_\mathrm{g}$ of the first hard splitting inside the jet by reclustering them using the Cambridge-Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, $R_\mathrm{AA}$, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in $r_\mathrm{g}$, jet transverse momentum, and in intervals of collision centrality. The $R_\mathrm{AA}$ value is observed to depend significantly on jet $r_\mathrm{g}$. Jets produced with the largest measured $r_\mathrm{g}$ are found to be twice as suppressed as those with the smallest $r_\mathrm{g}$ in central Pb+Pb collisions. The $R_\mathrm{AA}$ values do not exhibit a strong variation with jet $p_\mathrm{T}$ in any of the $r_\mathrm{g}$ intervals. The $r_\mathrm{g}$ and $p_\mathrm{T}$ dependence of jet $R_\mathrm{AA}$ is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach.
