"Table 174" 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.

CERN-LHC. 本文针对高能夸克与胶子形成喷注的碎裂（fragmentation）过程相关物理量开展测量研究。选取横动量（transverse momentum, $p_ ext{T}$）介于100 GeV至500 GeV、赝快度$|eta| < 2.5$的喷注，以探究喷注的精细结构。本研究针对每个事件中两束领头喷注内更靠前向与更靠近中心的喷注的碎裂特性展开分析。对实验数据开展展开校正（unfolding），以修正探测器分辨率与接收度效应带来的系统偏差。将实验数据与部分子阵雨（parton shower）蒙特卡罗（Monte Carlo）模拟程序进行比对后发现，现有模型能够在较宽的相空间范围内较好地复现实验数据，但二者仍存在显著差异。此外，本研究利用喷注味道组分的快度（rapidity）依赖关系，将实验数据按夸克初始喷注与胶子初始喷注的分类进行解读。采用与模型无关的喷注标记技术（主题建模，topic modeling）完成的带电粒子多重数首次测量，为替代传统依赖模拟输入的夸克与胶子喷注甄别方法提供了极具潜力的新思路。模拟程序能够在本次测量覆盖的喷注横动量范围内较好地描述类夸克喷注数据，但类胶子喷注的带电粒子多重数系统性低于模拟结果。实验不确定度按类别进行分解，除统计不确定度外，各数据分箱（bins）与各观测量之间的不确定度均视为完全相关。