Top quark pair production in association with a jet with NLO parton showering

TL;DR

This paper presents a next-to-leading order calculation of top quark pair production with an associated jet, integrated with parton shower algorithms to improve predictions at the hadron level, including top decay effects.

Contribution

It introduces a combined framework using POWHEG-BOX, HELAC, and PYTHIA/HERWIG for accurate NLO predictions of top pair plus jet production with parton shower matching.

Findings

Accurate cross section predictions at NLO matched with parton showers.

Inclusion of top quark decay at leading order within the simulation.

Framework compatible with existing event generators.

Abstract

We compute the production cross section of a top-antitop pair in association with a jet at hadron colliders at next-to-leading order accuracy matched with parton shower algorithms to make predictions at the hadron level. The parton shower allows for including the decay of the top quarks at the leading order accuracy. We use a framework based on three well established numerical codes, the POWHEG-BOX, used for the calculation of the cross section, HELAC, which generates the matrix elements for the Born-level, real emission and the virtual part, and finally a parton shower program, such as PYTHIA or HERWIG, which generate the parton-shower and hadronization.