Logarithmically-accurate and positive-definite NLO shower matching
Abstract
We present methods to achieve NLL+NLO accurate parton showering for processes with two coloured legs: neutral- and charged-current Drell-Yan, and Higgs production in collisions, as well as DIS and to jets. The methods include adaptations of existing approaches, as well as a new NLO matching scheme, ESME, that is positive-definite by construction. Our implementations of the methods within the PanScales framework yield highly competitive NLO event generation speeds. We validate the fixed-order and combined resummation accuracy with tests in the limit of small QCD coupling and briefly touch on phenomenological comparisons to standard NLO results and to Drell-Yan data. The progress reported here is an essential step towards showers with logarithmic accuracy beyond NLL for processes with incoming hadrons.
Keywords
Cite
@article{arxiv.2504.05377,
title = {Logarithmically-accurate and positive-definite NLO shower matching},
author = {Melissa van Beekveld and Silvia Ferrario Ravasio and Jack Helliwell and Alexander Karlberg and Gavin P. Salam and Ludovic Scyboz and Alba Soto-Ontoso and Gregory Soyez and Silvia Zanoli},
journal= {arXiv preprint arXiv:2504.05377},
year = {2025}
}
Comments
29 pages main text, 49 including appendices and references, 12 figures, public code available as part of 0.3.0 release of PanScales under http://gitlab.com/panscales/panscales-0.X; v2 matches the published version