Year: 2026
Type: preprint
Abstract: We present a resonance-aware extension of electroweak Sudakov-logarithm reweighting in MadGraph5_aMC@NLO for NLO QCD-matched and FxFx multijet-merged event samples. The method identifies the hard production process underlying each event and evaluates its electroweak Sudakov correction while accounting for the spin correlations between unstable particles and their decay products. Photonic logarithms are removed from the virtual weight to avoid overlap with QED shower evolution. We validate the method in FxFx-merged $Z$+jets production and fully leptonic $W^+W^-$ production. The reweighting yields the expected growing weak suppression in high-energy tails and is stable under variations of the clustering and merging parameters. In $W^+W^-$ production, the density-matrix and spin-summed prescriptions are statistically compatible for the observables studied, indicating only a small additional helicity dependence of the Sudakov correction in this channel. The method provides a practical virtual weak-Sudakov approximation for matched and merged simulations, but does not constitute an exact NLO electroweak calculation.
Source: arXiv (Cornell University)
Institutions: University of Ljubljana, Jožef Stefan Institute, Jožef Stefan International Postgraduate School, Lund University, Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Eötvös Loránd University, Uppsala University, University of Milan, Istituto Nazionale di Fisica Nucleare, Sezione di Milano
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: European Commission, NextGenerationEU
Awards: G231133531, G972786147
OpenAlex ID: W7220986189