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Leading-colour-based unweighted event generation for multi-parton tree-level processes

Frederix, Rikkert LU orcid and Vitos, Timea LU (2024) In Journal of High Energy Physics 2024(12).
Abstract

In this work, we revisit unweighted event generation for multi-parton tree-level processes in massless QCD. We introduce a two-step approach, in which initially unweighted events are generated at leading-colour (LC) accuracy, followed by a reweighting of these events to full-colour (FC) accuracy and applying an additional unweighting cycle. This method leverages the simple structure of LC integrands, enabling optimized phase-space parameterisations and resulting in high primary unweighting efficiencies, ranging from the percent level for 2 → 4 processes to the per-mille level for 2 → 7 processes. Given that the LC-accurate matrix elements closely approximate the FC-accurate ones, the secondary unweighting efficiencies exceed 50%. Our... (More)

In this work, we revisit unweighted event generation for multi-parton tree-level processes in massless QCD. We introduce a two-step approach, in which initially unweighted events are generated at leading-colour (LC) accuracy, followed by a reweighting of these events to full-colour (FC) accuracy and applying an additional unweighting cycle. This method leverages the simple structure of LC integrands, enabling optimized phase-space parameterisations and resulting in high primary unweighting efficiencies, ranging from the percent level for 2 → 4 processes to the per-mille level for 2 → 7 processes. Given that the LC-accurate matrix elements closely approximate the FC-accurate ones, the secondary unweighting efficiencies exceed 50%. Our results suggest that this two-step approach offers an efficient alternative to direct event generation at FC accuracy.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Automation, Higher-Order Perturbative Calculations
in
Journal of High Energy Physics
volume
2024
issue
12
article number
201
publisher
Springer
external identifiers
  • scopus:105004744491
ISSN
1029-8479
DOI
10.1007/JHEP12(2024)201
language
English
LU publication?
yes
id
3e67186e-5d38-42ef-b04d-ce82f482cad4
date added to LUP
2025-09-26 12:16:52
date last changed
2025-09-26 12:17:39
@article{3e67186e-5d38-42ef-b04d-ce82f482cad4,
  abstract     = {{<p>In this work, we revisit unweighted event generation for multi-parton tree-level processes in massless QCD. We introduce a two-step approach, in which initially unweighted events are generated at leading-colour (LC) accuracy, followed by a reweighting of these events to full-colour (FC) accuracy and applying an additional unweighting cycle. This method leverages the simple structure of LC integrands, enabling optimized phase-space parameterisations and resulting in high primary unweighting efficiencies, ranging from the percent level for 2 → 4 processes to the per-mille level for 2 → 7 processes. Given that the LC-accurate matrix elements closely approximate the FC-accurate ones, the secondary unweighting efficiencies exceed 50%. Our results suggest that this two-step approach offers an efficient alternative to direct event generation at FC accuracy.</p>}},
  author       = {{Frederix, Rikkert and Vitos, Timea}},
  issn         = {{1029-8479}},
  keywords     = {{Automation; Higher-Order Perturbative Calculations}},
  language     = {{eng}},
  number       = {{12}},
  publisher    = {{Springer}},
  series       = {{Journal of High Energy Physics}},
  title        = {{Leading-colour-based unweighted event generation for multi-parton tree-level processes}},
  url          = {{http://dx.doi.org/10.1007/JHEP12(2024)201}},
  doi          = {{10.1007/JHEP12(2024)201}},
  volume       = {{2024}},
  year         = {{2024}},
}