Logarithmically-accurate and positive-definite NLO shower matching

Journal article

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 pp collisions, as well as DIS and e+e− 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.

Authors: van Beekveld, M; Ferrario Ravasio, S; Helliwell, J; Karlberg, A; Salam, GP

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2025
• Issue: 10
• Article number: 38
• Publication date: 2025-10-03
• Acceptance date: 2025-08-24
• DOI: 10.1007/jhep10(2025)038
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Parton Shower; Resummation; Higher-Order Perturbative Calculations