Matching and event-shape NNDL accuracy in parton showers

Keith Hamilton, Alexander Karlberg, Gavin P. Salam, Ludovic Scyboz, Rob Verheyen

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)


To explore the interplay of NLO matching and next-to-leading logarithmic (NLL) parton showers, we consider the simplest case of γ* and Higgs-boson decays to qq¯ and gg respectively. Not only should shower NLL accuracy be retained across observables after matching, but for global event-shape observables and the two-jet rate, matching can augment the shower in such a way that it additionally achieves next-to-next-to-double-logarithmic (NNDL) accuracy, a first step on the route towards general NNLL. As a proof-of-concept exploration of this question, we consider direct application of multiplicative matrix-element corrections, as well as simple implementations of MC@NLO and POWHEG-style matching. We find that the first two straightforwardly bring NNDL accuracy, and that this can also be achieved with POWHEG, although particular care is needed in the handover between POWHEG and the shower. Our study involves both analytic and numerical components and we also touch on some phenomenological considerations.

Original languageEnglish
Article number224
Number of pages42
JournalJournal of High Energy Physics
Issue number3
Publication statusPublished - 28 Mar 2023
Externally publishedYes


  • Higher-Order Perturbative Calculations
  • Parton Shower
  • Resummation

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