TtW at NLO in QCD: Full off-shell effects and precision observables

TL;DR

This paper provides a detailed NLO QCD analysis of the ttW process, including off-shell effects, to improve the precision of theoretical predictions and address discrepancies with experimental data.

Contribution

It introduces full off-shell NLO QCD calculations for ttW, enhancing the accuracy of observables like cross section ratios and charge asymmetries.

Findings

The cross section ratio shows increased perturbative stability.

Off-shell effects significantly impact charge asymmetry predictions.

Modeling choices influence the precision of key observables.

Abstract

In light of recent tension between theory and experiment for the process ttW in the 3l channel, we present a phenomenological study of carefully chosen observables. We employ the full off-shell results at NLO QCD for ttW+ and ttW- to build the cross section ratio, an observable which is expected to exhibit enhanced perturbative stability. Furthermore, we also revisit the charge asymmetries of the top and its decay products at the fiducial integrated level. The impact of modelling is investigated for all observables.