论文标题
LHC在$ t \ bar {t}γ$生产中的顶级衰减建模的影响
Effects of top-quark decay modeling in $t\bar{t}γ$ production at the LHC
论文作者
论文摘要
我们对$ t \ bar {t}γ$最终状态的模型的不同方法进行了系统的比较，该状态在LHC处具有松性衰变。一方面，我们考虑了NLO QCD准确性的完整计算，其中包括所有谐振和非谐振图。另一方面，我们考虑以各种精确度模型的顶部夸克衰变在窄宽近似中进行预测。通过这种方式，我们量化了$ t \ bar {t}γ$生产中脱壳效应的影响。我们还讨论了在完整计算中双重，单一和非共振贡献的相对重要性。最后，我们研究了顶级夸克腐烂中孤立光子的比例，这代表了测量异常$Tγ$耦合的背景。
We present a systematic comparison of different approaches for the modeling of $t\bar{t}γ$ final states with leptonic decays at the LHC. On the one hand, we consider a complete calculation at NLO QCD accuracy which includes all resonant and non-resonant diagrams. On the other hand, we consider predictions in the narrow-width approximation with top quark decays modeled at various accuracies. In this way we quantify the impact of the off-shell effects in $t\bar{t}γ$ production. We also discuss the relative importance of double-, single- and non-resonant contributions in the complete calculation. Finally we investigate the fraction of isolated photons from decays of top quarks, which represent a background for measurements of anomalous $tγ$ couplings.
