Resonance-aware parton-shower matching for off-shell top-antitop production with semi-leptonic decays at electron-positron colliders

TL;DR

This paper develops a resonance-aware NLO QCD correction method for off-shell top-antitop production with semi-leptonic decays at electron-positron colliders, improving the accuracy of resonance line shapes in simulations.

Contribution

It introduces a novel resonance-aware matching procedure within the MC@NLO framework, tailored for off-shell top pair production with detailed resonance cascade information.

Findings

Accurate off-shell NLO QCD corrections implemented with resonance-aware matching.

Preservation of resonance line shapes in event simulations.

Enhanced precision in modeling top-antitop production at electron-positron colliders.

Abstract

We present full off-shell NLO corrections in QCD obtained with the MoCaNLO code matched to parton shower. A resonance-aware matching procedure has been devised for the MC@NLO method tuned to the Catani-Seymour dipole subtraction. Specifically, we consider the off-shell production of a top-antitop pair in the semi-leptonic decay channel in electron-positron collisions and match it to the final-state QCD parton shower of PYTHIA8. Distortions of resonances' line shapes are avoided by providing the details of the resonance-cascade chain on an event-by-event basis to the parton shower and by adapting the matching accordingly through the introduction of dedicated counterterms.