Soft QCD Effects in VBS/VBF Topologies

TL;DR

This paper examines how non-perturbative QCD effects like multi-parton interactions, colour reconnection, and hadronization influence the modeling of VBS final states at the LHC, highlighting their significant phase space dependence.

Contribution

It provides a detailed analysis of how variations in non-perturbative model parameters affect VBS predictions and their uncertainties at the LHC.

Findings

Non-perturbative effects vary non-trivially across phase space.

These effects can be as large as perturbative uncertainties when combined with NLO predictions.

Uncertainty estimates must include non-perturbative variations for accurate modeling.

Abstract

We consider the impact of multi-parton interactions, colour reconnection and hadronization on the modeling of vector boson fusion and vector boson scattering (VBS) final states at the Large Hadron Collider (LHC). We investigate how the variation of the model parameters, compatible with a reasonable spread of predictions around typical tuning observables, extrapolates into the VBS phase space. We study the implications of this variation on the total uncertainty budget attached to realistic simulation of the final states in current event generator predictions. We find that the variations have a non-trivial phase space dependence and become comparable in size to the perturbative uncertainties once next-to-leading order predictions are combined with parton shower evolution.