"Table 124" 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.

在质心系能量√s=13 TeV的质子-质子碰撞中，研究人员测量了顶夸克对（top quark pair）产生的微分截面与双微分截面（differential and double-differential cross sections），测量结果以顶夸克及顶夸克-反夸克（ttbar）系统的运动学变量（kinematic variables）为函数形式给出。此外，本研究还测量了与ttbar产生过程相关的喷注（jet）的运动学变量及多重数（multiplicity）。本分析基于大型强子对撞机（Large Hadron Collider, LHC）上的紧凑μ子线圈（Compact Muon Solenoid, CMS）实验在2016年采集的数据，对应积分亮度为35.8 fb⁻¹。测量工作在末态包含单μ子或单电子及喷注的轻子+喷注衰变道（lepton+jets decay channels）中开展。微分截面分别在接近实验接收度的相空间内的粒子层次，以及全相空间内的部分子层次上呈现。将本次测量结果与若干采用不同方法和近似方案的标准模型（Standard Model, SM）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，但尚无一种预言模型能够复现所有的测量分布。具体而言，顶夸克的横动量分布比理论预言值下降得更为陡峭。喷注的运动学分布及多重数可通过次领头阶（next-to-leading-order, NLO）计算与部分子簇射（parton shower）模型的若干组合得到较好的描述。