论文标题
$ t \ bar {t}+γ/z $生产在LHC中
Off-shell effects in $t\bar{t}+γ/Z$ production at the LHC
论文作者
论文摘要
我们提出了$ t \ bar {t}γ$和$ t \ bar {t} z（z \ toν_\ ell \barν_\ ell）$生产的最新预测。第一个过程可以提供有关顶级耦合到光子的强度和结构的关键信息。隐形 - decay频道$ t \ bar {t} z（z \ toν_\ ell \barν_\ ell）$是$ t \ bar {t}+e_ {t}+e_ {t}^{t}^{miss} $最终状态的深色物质搜索的重要SM背景。我们的结果是在QCD中准确的，其中包括所有共鸣和非谐振图，顶级夸克的干扰和脱壳效果以及$ w/z $ bosons。因此，它们从固定阶计算的角度来表示这些过程的最完整描述。我们显示了13 TEV的LHC Run II能量的选定结果，重点是选择动机良好的量表以及使用不同方法对顶级夸克衰变建模的效果。
We present state-of-the-art predictions for $t\bar{t}γ$ and $t\bar{t}Z(Z \to ν_\ell\barν_\ell)$ production in the fully leptonic channel at the LHC. The first process can provide key information on the strength and structure of the top-quark coupling to the photon. The invisible-decay channel $t\bar{t}Z(Z \to ν_\ell\barν_\ell)$ is an important SM background for Dark Matter searches in $t\bar{t}+E_{T}^{miss}$ final states. Our results are accurate to NLO in QCD and include all resonant and non-resonant diagrams, interferences and off-shell effects for top quarks and $W/Z$ bosons. As such, they represent the most complete description of these processes from the viewpoint of a fixed-order calculation. We show selected results for the LHC Run II energy of 13 TeV, focusing on the impact of choosing well motivated scales and on the effect of using different approaches for the modeling of top quark decays.
