Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 26: Higgs physics (theory)

T 26.1: Vortrag

Dienstag, 16. März 2021, 16:00–16:15, Ta

Parton-shower effects in Higgs production via Vector-Boson Fusion — Barbara Jäger¹, Alexander Karlberg², Simon Plätzer³, •Johannes Scheller¹, and Marco Zaro⁴ — ¹Institute for Theoretical Physics, University of Tübingen, Germany — ²Rudolf Peierls Centre for Theoretical Physics, University of Oxford, United Kingdom — ³Particle Physics, Faculty of Physics, and Erwin Schrödinger Institute for Mathematics and Physics, University of Vienna, Austria — ⁴INFN Sezione di Milano & TifLab, Italy

We present a systematic investigation of parton-shower and matching uncertainties of perturbative origin for Higgs-boson production via vector-boson fusion. To this end we employ different generators at next-to-leading order QCD accuracy matched with shower Monte Carlo programs, PYTHIA8, and HERWIG7, and a next-to-next-to-leading order QCD calculation. We thoroughly analyse the intrinsic sources of uncertainty within each generator, and then compare predictions among the different tools using the respective recommended setups. Within typical vector-boson fusion cuts, the resulting uncertainties on observables that are accurate to next-to-leading order are at the 10% level for rates and even smaller for shapes. For observables sensitive to extra radiation effects uncertainties of about 20% are found. We conclude that for vector-boson fusion processes an assessment of the uncertainties associated with simulation at next-to-leading order matched to parton showers based only on the variation of renormalisation, factorisation and shower scales systematically underestimates their true size.