"Table 3" of "Measurement of differential cross sections for the production of top quark pairs and of additional jets in lepton+jets events from pp collisions at $\sqrt{s} =$ 13 TeV"

Differential and double-differential cross sections for the production of top quark pairs in proton-proton collisions at sqrt{s} = 13 TeV are measured as a function of kinematic variables of the top quarks and the top quark-antiquark (ttbar) system. In addition, kinematic variables and multiplicities of jets associated with the ttbar production are measured. This analysis is based on data collected by the CMS experiment at the LHC in 2016 corresponding to an integrated luminosity of 35.8/fb. The measurements are performed in the lepton+jets decay channels with a single muon or electron and jets in the final state. The differential cross sections are presented at the particle level, within a phase space close to the experimental acceptance, and at the parton level in the full phase space. The results are compared to several standard model predictions that use different methods and approximations. The kinematic variables of the top quarks and the ttbar system are reasonably described in general, though none predict all the measured distributions. In particular, the transverse momentum distribution of the top quarks is more steeply falling than predicted. The kinematic distributions and multiplicities of jets are adequately modeled by certain combinations of next-to-leading-order calculations and parton shower models.

本研究测量了质心系能量√s=13太电子伏特（TeV）的质子-质子碰撞中顶夸克对（top quark pairs）的产生过程的微分与双微分截面，测量结果以顶夸克及顶夸克-反顶夸克（ttbar）系统的运动学变量为函数形式呈现。此外，本研究还对与ttbar产生过程相关的喷注的运动学变量与多重数进行了测量。本次分析基于大型强子对撞机（Large Hadron Collider, LHC）上的紧凑型缪子螺线管（Compact Muon Solenoid, CMS）实验在2016年采集的数据，对应积分亮度为35.8反飞靶恩。本次测量在末态包含单个缪子、电子与喷注的轻子+喷注衰变道中开展。微分截面分别在接近实验接受度的相空间内的粒子级，以及全相空间内的部分子级给出。研究结果与若干采用不同方法与近似方案的标准模型（Standard Model）预言进行了对比。总体而言，顶夸克及ttbar系统的运动学变量得到了合理描述，但尚无任何一项预言能够复现所有的测量分布。尤为特别的是，顶夸克的横向动量分布相较于理论预言更为陡降。部分喷注的运动学分布与多重数可通过次领头阶（next-to-leading-order, NLO）计算与部分子簇射模型的特定组合得到恰当的建模描述。