论文标题
首次测量顶级夸克对生产的横截面，并在$ \ sqrt {s} = $ 13 tev中使用DiLeptonic最终状态使用额外的魅力喷射
First measurement of the cross section for top quark pair production with additional charm jets using dileptonic final states in pp collisions at $\sqrt{s} = $ 13 TeV
论文作者
论文摘要
提出了与另外两个额外的魅力喷气机联合产生的顶级夸克对（$ \ mathrm {t \ bar {t}} $）的首次测量。该分析使用$ \ mathrm {t \ bar {t}} $事件的最终状态，在质子 - 普罗顿碰撞中产生的事件在13 tev的质量中心碰撞中产生。数据对应于LHC的CMS实验记录的41.5 fb $^{ - 1} $的集成光度。一种新的Charm Jet标识算法提供了对神经网络的输入，该算法经过训练以区分$ \ Mathrm {t \ bar {t}} $事件，带有两个附加的魅力（$ \ mathrm {t \ bar {t} （$ \ mathrm {t \ bar {t} b \ bar {b}} $），以及light-flavour或gluon（$ \ mathrm {t \ bar {t} ll} ll} $）jets。通过模板拟合步骤，包含$ \ Mathrm {t \ bar {t} c \ bar {c}} $，$ \ mathrm {t \ bar {t} b \ bar {b {b}}} $，以及$ \ mathrm { $ \ mathrm {t \ bar {t}} $ +两个喷气机交叉部分。这提供了$ \ mathrm {t \ bar {t} c \ bar {c}} $和$ \ mathrm {在整个相空间中分别为0.56（Syst）Pb。比较结果并发现与来自两个不同矩阵元件发生器的预测一致，其量子染色体动力学的次要顺序准确性与Parton Shower模拟相连。
The first measurement of the inclusive cross section for top quark pairs ($\mathrm{t\bar{t}}$) produced in association with two additional charm jets is presented. The analysis uses the dileptonic final states of $\mathrm{t\bar{t}}$ events produced in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 41.5 fb$^{-1}$, recorded by the CMS experiment at the LHC. A new charm jet identification algorithm provides input to a neural network that is trained to distinguish among $\mathrm{t\bar{t}}$ events with two additional charm ($\mathrm{t\bar{t}c\bar{c}}$), bottom ($\mathrm{t\bar{t}b\bar{b}}$), and light-flavour or gluon ($\mathrm{t\bar{t}LL}$) jets. By means of a template fitting procedure, the inclusive $\mathrm{t\bar{t}c\bar{c}}$, $\mathrm{t\bar{t}b\bar{b}}$, and $\mathrm{t\bar{t}LL}$ cross sections are simultaneously measured, together with their ratios to the inclusive $\mathrm{t\bar{t}}$ + two jets cross section. This provides measurements of the $\mathrm{t\bar{t}c\bar{c}}$ and $\mathrm{t\bar{t}b\bar{b}}$ cross sections of 10.1 $\pm$ 1.2 (stat) $\pm$ 1.4 (syst) pb and 4.54 $\pm$ 0.35 (stat) $\pm$ 0.56 (syst) pb, respectively, in the full phase space. The results are compared and found to be consistent with predictions from two different matrix element generators with next-to-leading order accuracy in quantum chromodynamics, interfaced with a parton shower simulation.
