Parton-shower Effects in Vector-Boson-Fusion Processes

TL;DR

This paper examines how combining next-to-leading order QCD calculations with different parton-shower algorithms affects predictions for vector-boson-fusion induced W+W−jj production, focusing on uncertainties and key distribution features.

Contribution

It provides a detailed comparison of angular-ordered and dipole-based parton showers combined with various matching schemes in VBF processes.

Findings

Parton-shower effects significantly influence key distributions.

Different shower algorithms and matching schemes yield comparable results within uncertainties.

Consistent scale variation treatment improves the reliability of theoretical predictions.

Abstract

We investigate the effects of combining next-to-leading order QCD results with parton-shower effects in $W^+W^-jj$ production via vector-boson fusion including leptonic decays. Using the Herwig 7 framework interfaced to VBFNLO 3, we compare the predictions obtained from the angular-ordered and dipole-based parton shower algorithms combined with subtractive, MC@NLO-type, and multiplicative, Powheg-type, matching. A consistent treatment of renormalisation and factorisation scale variations in the hard process and the parton shower allows to assign more reliable theory uncertainty predictions to key distributions like the central rapidity gap.