Single top-quark production with SHERPA

TL;DR

This paper presents next-to-leading order QCD predictions for single top-quark production at 8 TeV LHC using SHERPA, showing good agreement with measurements and analyzing uncertainties from various sources.

Contribution

It provides the first NLO QCD predictions for single top-quark production with SHERPA, including uncertainty quantification and impact of PDF choices.

Findings

Predictions agree well with experimental data.

Uncertainties are about 5-10% from flavor scheme choices.

Parton distribution functions significantly affect results.

Abstract

We present results at next-to-leading order accuracy in QCD for single top-quark production in the $t$, $s$ and $tW$ channels at the LHC at a centre-of-mass energy of 8 TeV, obtained with the SHERPA event generator. We find them in very good agreement with measured values and quantify their theory uncertainties. Uncertainties stemming from the choice between the four- and the five-flavour scheme are found to be typically of the order of 5-10 % over large ranges of phase space. We discuss the impact of parton distribution functions, and in particular of the bottom PDF. We also show how different cuts on QCD radiation patterns improve the signal-to-background ratio in realistic fiducial volumes.