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arXiv 1803.08856hep-ex
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$\sqrt{s} =$ 13 TeV pp碰撞产生顶夸克对和轻子+喷注事件中附加喷注的微分截面测量

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

CMS Collaboration

摘要:

测量了13 TeV质子-质子碰撞中顶夸克对产生的微分和双微分截面,它们是顶夸克和顶夸克-反夸克($\mathrm{t}\overline{\mathrm{t}}$)系统运动学变量的函数.此外,测量了与$\mathrm{t}\overline{\mathrm{t}}$生产相关的射流的运动学变量和多重性。该分析基于2016年LHC CMS实验收集的数据,对应于35.8 fb $^{-1}$的积分亮度。测量是在轻子+喷流衰变通道中进行的,其中单个μ子或电子和喷流处于最终状态。微分截面是在粒子水平,在一个相空间接近实验接受,并在部分子水平的全相空间。将结果与使用不同方法和近似值的几个标准模型预测进行比较。顶夸克和$\mathrm{t}\overline{\mathrm{t}}$系统的运动学变量在总体上得到了合理的描述,尽管没有一个能预测所有的测量分布。特别是,顶夸克的横向动量分布比预测的更陡。射流的运动学分布和多重性充分模拟的次领先的顺序计算和部分子簇射模型的某些组合。

英文摘要:

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 ($\mathrm{t}\overline{\mathrm{t}}$) system. In addition, kinematic variables and multiplicities of jets associated with the $\mathrm{t}\overline{\mathrm{t}}$ 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$^{-1}$. 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 $\mathrm{t}\overline{\mathrm{t}}$ 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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