Simplifying QCD event generation with chirality flow, reference vectors and spin directions
(2024) In Journal of High Energy Physics 2024(2).- Abstract
The chirality-flow formalism, combined with good choices of gauge reference vectors, simplifies tree-level calculations to the extent that it is often possible to write down amplitudes corresponding to Feynman diagrams immediately. It has also proven to give a very sizable speedup in a proof of concept implementation of massless tree-level QED in MadGraph5_aMC@NLO. In the present paper we extend this analysis to QCD, including massive quarks. We define helicity-dependent versions of the gluon vertices, derive constraints on the spinor structure of propagating gluons, and explore the Schouten identity to simplify the four-gluon vertex further. For massive quarks, the chirality-flow formalism sheds light on how to exploit the freedom to... (More)
The chirality-flow formalism, combined with good choices of gauge reference vectors, simplifies tree-level calculations to the extent that it is often possible to write down amplitudes corresponding to Feynman diagrams immediately. It has also proven to give a very sizable speedup in a proof of concept implementation of massless tree-level QED in MadGraph5_aMC@NLO. In the present paper we extend this analysis to QCD, including massive quarks. We define helicity-dependent versions of the gluon vertices, derive constraints on the spinor structure of propagating gluons, and explore the Schouten identity to simplify the four-gluon vertex further. For massive quarks, the chirality-flow formalism sheds light on how to exploit the freedom to measure spin along any direction to shorten the calculations. Overall, this results in a clear speedup for treating the Lorentz structure at high multiplicities.
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- author
- Boman, Emil LU ; Lifson, Andrew LU ; Sjodahl, Malin LU ; Warnerbring, Adam and Wettersten, Zenny
- organization
- publishing date
- 2024-02
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Automation, Chiral Lagrangian, Specific QCD Phenomenology
- in
- Journal of High Energy Physics
- volume
- 2024
- issue
- 2
- article number
- 5
- publisher
- Springer
- external identifiers
-
- scopus:85183753510
- ISSN
- 1029-8479
- DOI
- 10.1007/JHEP02(2024)005
- language
- English
- LU publication?
- yes
- id
- 1fd12341-2b5e-4ad4-8d50-0776e92fc2f9
- date added to LUP
- 2024-02-29 12:06:54
- date last changed
- 2024-02-29 12:09:07
@article{1fd12341-2b5e-4ad4-8d50-0776e92fc2f9,
abstract = {{<p>The chirality-flow formalism, combined with good choices of gauge reference vectors, simplifies tree-level calculations to the extent that it is often possible to write down amplitudes corresponding to Feynman diagrams immediately. It has also proven to give a very sizable speedup in a proof of concept implementation of massless tree-level QED in MadGraph5_aMC@NLO. In the present paper we extend this analysis to QCD, including massive quarks. We define helicity-dependent versions of the gluon vertices, derive constraints on the spinor structure of propagating gluons, and explore the Schouten identity to simplify the four-gluon vertex further. For massive quarks, the chirality-flow formalism sheds light on how to exploit the freedom to measure spin along any direction to shorten the calculations. Overall, this results in a clear speedup for treating the Lorentz structure at high multiplicities.</p>}},
author = {{Boman, Emil and Lifson, Andrew and Sjodahl, Malin and Warnerbring, Adam and Wettersten, Zenny}},
issn = {{1029-8479}},
keywords = {{Automation; Chiral Lagrangian; Specific QCD Phenomenology}},
language = {{eng}},
number = {{2}},
publisher = {{Springer}},
series = {{Journal of High Energy Physics}},
title = {{Simplifying QCD event generation with chirality flow, reference vectors and spin directions}},
url = {{http://dx.doi.org/10.1007/JHEP02(2024)005}},
doi = {{10.1007/JHEP02(2024)005}},
volume = {{2024}},
year = {{2024}},
}