Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 126: Top physics 5 (top mass)
T 126.5: Talk
Friday, March 8, 2024, 10:00–10:15, Geb. 30.95: Audimax
Improvements of the matching uncertainty definition in top-quark processes simulated with Powheg+Pythia8 — •Dominic Hirschbühl, Wolfgang Wagner, and Joshua Reidelstürz — Bergische Universität Wuppertal
Top-quark processes are modelled by the ATLAS Collaboration by matching the hard-scatter matrix element calculations of next-to-leading order Monte-Carlo generators with a parton shower generator. This talk presents a comprehensive study of the uncertainty related to the matching procedure and a new strategy to evaluate this uncertainty. The new approach is based on the Pythia 8 parton-shower matching parameter pThard. It is designed to surpass the previous method, which involved comparing two generator setups to cover the uncertainty. The old method entangled all differences between the two setups in a single uncertainty while the new prescription implements a focused uncertainty that avoids double-counting with other uncertainties on the modelling of the top processes. Additionally first matching studies of a NNLO matrix element generator matched to parton shower are presented.
Keywords: Top-Quark; Monte-Carlo; Pythia8; Parton shower; Matching