Parton shower effects in $t\bar{t}W^\pm$ production at NLO QCD

TL;DR

This paper studies the impact of parton shower effects on $t\bar{t}W^{\pm}$ production at NLO QCD at the LHC, analyzing theoretical uncertainties and different contribution schemes for improved predictions.

Contribution

It provides a detailed analysis of parton shower effects and uncertainties in $t\bar{t}W^{\pm}$ production at NLO QCD, including separate and combined contributions.

Findings

Quantified uncertainties from higher-order corrections.

Compared different contribution schemes at NLO.

Assessed impact of parton-shower matching on predictions.

Abstract

We present a selection of results from our recent study of $pp\to t\bar{t}W^\pm$ production matched to partons showers at NLO QCD at the LHC. Theoretical predictions are obtained at perturbative orders $\mathcal{O}(\alpha_s^3\alpha)$ and $\mathcal{O}(\alpha_s\alpha^3)$, where the different contributions are studied first separately at the inclusive level before being combined within a realistic two same-sign lepton signature. We investigate in detail uncertainties originating from missing higher-order corrections and from the parton-shower matching scheme employed.