QCD NLO with Powheg matching and top threshold matching in WHIZARD

TL;DR

This paper discusses the automation of NLO QCD calculations in WHIZARD, including matching with threshold resummation for top pair production, enabling detailed studies of collider processes with improved accuracy.

Contribution

It introduces automation of NLO QCD processes and threshold matching in WHIZARD, enhancing its capability to simulate complex collider phenomena with electroweak and relativistic corrections.

Findings

Validated NLO processes for e+e- collisions

Implemented top threshold resummation matching

Enabled detailed observable analysis in WHIZARD

Abstract

We present the status of the automation of NLO processes within the event generator WHIZARD. The program provides an automated FKS subtraction and phase space integration over the FKS regions, while the (QCD) NLO matrix element is accessed via the Binoth Les Houches Interface from an externally linked one-loop program. Massless and massive test cases and validation are shown for several e+e- processes. Furthermore, we discuss work in progress and future plans. The second part covers the matching of the NRQCD prediction with NLL threshold resummation to the NLO continuum top pair production at lepton colliders. Both the S-wave and P-wave production of the top pair are taken into account in the resummation. The inclusion in WHIZARD allows to study more exclusive observables than just the total cross section and automatically accounts for important electroweak and relativistic corrections in the threshold region.