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| Hauptverfasser: | , , , , |
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| Format: | Preprint |
| Veröffentlicht: |
2023
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| Online-Zugang: | https://arxiv.org/abs/2312.07447 |
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| _version_ | 1866917591127162880 |
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| author | Boman, Emil Lifson, Andrew Sjodahl, Malin Warnerbring, Adam Wettersten, Zenny |
| author_facet | Boman, Emil Lifson, Andrew Sjodahl, Malin Warnerbring, Adam Wettersten, Zenny |
| contents | 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2312_07447 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Simplifying QCD event generation with chirality flow, reference vectors and spin directions Boman, Emil Lifson, Andrew Sjodahl, Malin Warnerbring, Adam Wettersten, Zenny High Energy Physics - Phenomenology 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. |
| title | Simplifying QCD event generation with chirality flow, reference vectors and spin directions |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2312.07447 |