"Figure 8 (left) u4L[Z120]" of "Study of quark and gluon jet substructure in Z+jet and dijet events from pp collisions"

Measurements of jet substructure describing the composition of quark- and gluon-initiated jets are presented. Proton-proton (pp) collision data at sqrt(s)=13 TeV collected with the CMS detector are used, corresponding to an integrated luminosity of 35.9/fb. Generalized angularities are measured that characterize the jet substructure and distinguish quark- and gluon-initiated jets. These observables are sensitive to the distributions of transverse momenta and angular distances within a jet. The analysis is performed using a data sample of dijet events enriched in gluon-initiated jets, and, for the first time, a Z+jet event sample enriched in quark-initiated jets. The observables are measured in bins of jet transverse momentum, and as a function of the jet radius parameter. Each measurement is repeated applying a "soft drop" grooming procedure that removes soft and large angle radiation from the jet.For easier navigation, figures are named with a code with each letter/number representing in the following order: ungroomed/groomed, AK4/AK8, charged, multiplicity/pTD2/thrust/width/LHA, [central dijet/forward dijet/Z+jet, PT].

本工作报道了描述夸克引发喷注与胶子引发喷注组成的喷注子结构测量结果。实验使用了CMS探测器（CMS detector）采集的质心系能量√s=13 TeV的质子-质子（pp）碰撞数据，对应积分亮度为35.9 fb⁻¹。研究测量了广义角距可观测量（Generalized angularities），该类可观测量可用于表征喷注子结构并区分夸克与胶子引发的喷注。这些可观测量对喷注内部的横向动量与角间距的分布具有敏感性。分析采用了富含胶子引发喷注的双喷注事例数据样本，并首次使用了富含夸克引发喷注的Z+喷注事例数据样本。可观测量以喷注横向动量为分箱进行测量，并随喷注半径参数变化开展测量。每一项测量均重复执行了"软下落（soft drop）"喷注修整操作，该操作可去除喷注内的软辐射与大角度辐射。为便于查阅，所有图表均采用编码命名，各字母/数字依次代表：未修整/修整状态、AK4/AK8喷注算法、带电粒子、多重数/pTD2/喷注重心/喷注宽度/LHA可观测量、[中心区双喷注/前向区双喷注/Z+喷注事例、横向动量]。