NLO QCD corrections to off-shell top-antitop production with leptonic decays at hadron colliders

By Ansgar Denner, Stefan Dittmaier, Stefan Kallweit, Stefano Pozzorini. Journal of High Energy Physics, 2012

155 citations recorded by the source corpus.

We present details of a calculation of the cross section for hadronic top-antitop production in next-to-leading order (NLO) QCD, including the decays of the top and antitop into bottom quarks and leptons. This calculation is based on matrix elements for νee+μ−\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ {{\overline{\nu}}_{\mu }}\mathrm{b}\overline{\mathrm{b}} $\end{document} production and includes all non-resonant diagrams, interferences, and off-shell effects of the top quarks. Such contributions are formally suppressed by the top-quark width and turn out to be small in the inclusive cross section. However, they can be strongly enhanced in exclusive observables that play an important role in Higgs and new-physics searches. Also non-resonant and off-shell effects due to the finite W-boson width are investigated in detail, but their impact is much smaller than naively expected. We also introduce a matching approach to improve NLO calculations involving intermediate unstable particles. Using a fixed QCD scale leads to perturbative instabilities in the high-energy tails of distributions, but an appropriate dynamical scale stabilises NLO predictions. Numerical results for the total cross section, several distributions, and asymmetries are presented for Tevatron and the LHC at 7 TeV, 8 TeV, and 14 TeV.

View Paper: https://www.semanticscholar.org/paper/69322641e16927f4a7228178b9e4846d735a18fa

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Citations in the corpus

NLO electroweak automation and precise predictions for W + multijet production at the LHC (2014, methodology): “To this end we implemented NLO EW corrections in a second and fully independent in-house generator, which was originally developed for NLO QCD calculations [59, 103].”
Electroweak radiative corrections for collider physics (2019, background): “Therefore, in a diagram-by-diagram approach [345, 346], also the sum over b in Eq.”
Dynamical scales for multi-TeV top-pair production at the LHC (2016, unknown): “[22, 25] a geometric average scale (see eq.”
Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report (2017, methodology): “Munich Munich14 is a fully general and very fast parton-level Monte Carlo integrator, written in C++, which was originally developed in the context of multi-leg NLO QCD calculations [342, 343, 348, 488].”
Top-pair production and decay at NLO matched with parton showers (2014, methodology): “[25, 26], (that will be referred to in the rest of this paper as DDKP), and in refs.”