论文标题

NLO QCD+EW预测$ thj $和LHC的$ TZJ $生产

NLO QCD+EW predictions for $tHj$ and $tZj$ production at the LHC

论文作者

Pagani, Davide, Tsinikos, Ioannis, Vryonidou, Eleni

论文摘要

在这项工作中,我们计算了与Higgs($ thj $)或NLO QCD+EW精度相关的单个顶级夸克或Antiquark的横截面。在$ tzj $生产的情况下,我们认为$ z $ boson的情况均未确定和完整的最终状态$ t \ ell^+ \ ell^ - j $,包括脱机和非共振效果。我们在不选择任何特定的生产渠道($ s $ - ,$ t $ - 或$ tw $)的情况下执行了五流式SCHEME(5FS)的计算。此外,我们通过仔细仔细(包括四频cheme(4FS)和5FS预测之间的差异)提供了对理论不确定性的更现实的估计。详细讨论了在EW校正的情况下进行此过程的困难。我们发现,只有在考虑到风味方案不确定性(4fs vs.〜5fs)时,NLO EW校正通常是在NLO QCD理论不确定性中。对于$ t \ ell^+ \ ell^ - j $生产,我们还研究了NLO QCD+ EW预测和NLO QCD预测之间的差异,该预测与Parton淋浴模拟匹配,包括多个光子排放。

In this work we calculate the cross sections for the hadroproduction of a single top quark or antiquark in association with a Higgs ($tHj$) or $Z$ boson ($tZj$) at NLO QCD+EW accuracy. In the case of $tZj$ production we consider both the case of the $Z$ boson undecayed and the complete final state $t \ell^+ \ell^- j$, including off-shell and non-resonant effects. We perform our calculation in the five-flavour-scheme (5FS), without selecting any specific production channel ($s$-, $t$- or $tW$ associated). Moreover, we provide a more realistic estimate of the theory uncertainty by carefully including the differences between the four-flavour-scheme (4FS) and 5FS predictions. The difficulties underlying this procedure in the presence of EW corrections are discussed in detail. We find that NLO EW corrections are in general within the NLO QCD theory uncertainties only if the flavour scheme uncertainty (4FS vs.~5FS) is taken into account. For the case of $t \ell^+ \ell^- j$ production we also investigate differences between NLO QCD+EW predictions and NLO QCD predictions matched with a parton shower simulation including multiple photon emissions.

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