论文标题
差异$ \ mathrm {t \ bar {t}} $的测量$ \ sqrt {s} = $ 13 TEV
Measurement of differential $\mathrm{t\bar{t}}$ production cross sections using top quarks at large transverse momenta in pp collisions at $\sqrt{s} =$ 13 TeV
论文作者
论文摘要
据报道，测量了差分顶夸克对（$ \ mathrm {t \ bar {t}} $）生产横截面，其中最大的夸克是在大型横向动量处产生的。 LHC上使用CMS检测器收集的数据来自PP碰撞，质量中心能量为13 TEV，对应于35.9 fb $^{ - 1} $的集成光度。该测量使用的事件将至少一个顶级夸克（T $ \ to $ wb $ \ to $ qq'b）衰减，并被重建为大型拉迪乌斯喷气机，横向动量超过400 GEV。从重建的电子或MUON，底部夸克射流以及由于未发现的中微子而导致的横向动量，需要以类似的方式或诱变的方式腐烂，或者是棘手的。将横截面作为单个顶级夸克的运动学变量或$ \ mathrm {t \ bar {t}} $ system提取的函数。结果在接近实验验收的相位区域和Parton级别的相位区域内呈现，并与各种理论模型进行了比较。在两个衰减通道中，观察到的绝对横截面显着低于理论的预测，而归一化的差异测量值很好地描述了。
A measurement is reported of differential top quark pair ($\mathrm{t\bar{t}}$) production cross sections, where top quarks are produced at large transverse momenta. The data collected with the CMS detector at the LHC are from pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The measurement uses events where at least one top quark decays as t $\to$ Wb $\to$ qq'b and is reconstructed as a large-radius jet with transverse momentum in excess of 400 GeV. The second top quark is required to decay either in a similar way, or leptonically, as inferred from a reconstructed electron or muon, a bottom quark jet, and a missing transverse momentum due to the undetected neutrino. The cross section is extracted as a function of kinematic variables of individual top quarks or of the $\mathrm{t\bar{t}}$ system. The results are presented at the particle level, within a region of phase space close to that of the experimental acceptance, and at the parton level, and are compared to various theoretical models. In both decay channels the observed absolute cross sections are significantly lower than the predictions from theory, while the normalized differential measurements are well described.
