"Table 18" 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（sqrt{s}）=13 TeV的质子-质子碰撞中，我们针对顶夸克对产生过程的微分截面与双微分截面，以顶夸克自身以及顶夸克-反夸克（ttbar）系统的运动学变量为函数开展了测量；此外，本分析还对与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。本分析基于大型强子对撞机（Large Hadron Collider, LHC）上的紧凑型μ子线圈（Compact Muon Solenoid, CMS）实验于2016年采集的数据，该数据集对应的积分亮度为35.8 fb⁻¹。本次测量选取末态包含单μ子或单电子以及喷注的轻子+喷注衰变道进行，微分截面测量分别在接近实验接收度的相空间内的粒子层级，以及全相空间内的部分子层级上进行呈现。我们将测量结果与若干采用不同方法与近似方案的标准模型（Standard Model, SM）预言进行了对比，结果显示总体而言顶夸克与ttbar系统的运动学变量得到了合理的描述，但没有任何一个预言模型能够复现全部测量分布；具体而言，顶夸克的横向动量分布的下降趋势比预言结果更为陡峭，而部分喷注的运动学分布与多重数则可通过若干次领头阶（next-to-leading-order, NLO）计算与部分子喷注模型的组合得到充分的描述。

搜集汇总

背景与挑战

背景概述

该数据集是CMS实验在13 TeV质子-质子碰撞中测量顶夸克对产生微分截面的Table 18部分，具体关注附加喷注与顶夸克对质量（M(tt¯)）的绝对截面函数。数据基于2016年收集的35.8/fb积分亮度，在轻子+喷注衰变通道中测量，提供了从300 GeV到2000 GeV质量区间的微分截面值，并包含统计和系统不确定性，用于验证标准模型预测和理论计算。