"Table 1" of "Properties of jet fragmentation using charged particles measured with the ATLAS detector in $pp$ collisions at $\sqrt{s}=13$ TeV"

CERN-LHC. This paper presents a measurement of quantities related to the formation of jets from high energy quarks and gluons (fragmentation). Jets with $100$ GeV $ 500$ MeV~and $|\eta| < 2.5$~are used to probe the detailed structure of the jet. The fragmentation properties of the more forward and the more central of the leading two jets from each event are studied. The data are unfolded to correct for detector resolution and acceptance effects. Comparisons to parton shower Monte Carlo generators indicate that existing models provide a reasonable description of the data across a wide range of phase space, but there are also significant differences. Furthermore, the data are interpreted in the context of quark- and gluon-initiated jets by exploiting the rapidity dependence of the jet flavor fraction. A first measurement of the charged-particle multiplicity using model-independent jet labels (topic modeling) provides a promising alternative to traditional quark- and gluon- extractions using simulation input. The simulations provide a reasonable description of the quark-like data across the jet $p_\text{T}$ range presented in this measurement, but the gluon-like data have systematically fewer charged particles than the simulations. Uncertainties are broken down by category and should be treated as fully correlated between bins and between observables except for statistical uncertainties.

欧洲核子研究中心大型强子对撞机（CERN-LHC）。本文针对高能夸克（quark）与胶子（gluon）形成喷注（jet）的相关物理量（即喷注碎裂（fragmentation）过程）开展测量。选取横向动量（transverse momentum, $p_ ext{T}$）介于100 GeV至500 GeV、赝快度（pseudorapidity）$|eta|<2.5$的喷注（jet），用以探究喷注的精细结构。本研究针对每个事件中前两喷注中快度更靠前与更居中的喷注的碎裂特性展开分析。通过数据解卷（unfolding）以修正探测器分辨率与接收度效应。将测量数据与部分子簇射（parton shower）型蒙特卡洛（Monte Carlo）发生器的模拟结果对比后发现，现有模型可在较宽相空间范围内对实验数据给出合理描述，但二者仍存在显著差异。此外，借助喷注味组分的快度依赖特性，可将实验数据在夸克引发与胶子引发喷注的框架下进行解读。首次借助与模型无关的喷注标签（主题建模（topic modeling））开展带电粒子多重数（charged-particle multiplicity）的测量，为传统依靠模拟输入提取夸克与胶子喷注的方法提供了极具前景的替代路径。模拟结果可在本次测量覆盖的喷注横向动量（$p_ ext{T}$）范围内对类夸克数据给出合理描述，但类胶子数据的带电粒子多重数系统性低于模拟结果。不确定度按类别拆分，除统计不确定度外，所有分箱（bin）与观测量之间的不确定度均视为完全相关。