What are the Feynman diagrams for tree-level 5-gluon scattering?

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Discussion Overview

The discussion revolves around identifying the Feynman diagrams that contribute to tree-level scattering of five gluons. Participants explore the context of using various techniques for calculating amplitudes in quantum chromodynamics (QCD) and the specific challenge of listing all relevant diagrams without including loop contributions.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • earth2 requests a list of Feynman diagrams for tree-level 5-gluon scattering, indicating a comparison with other techniques.
  • Some participants suggest that the question may need clarification regarding the inclusion of loops, as this would lead to an infinite number of diagrams.
  • earth2 clarifies that only tree-level diagrams are of interest, explicitly stating that loops should not be included.
  • It is noted that the QCD Lagrangian contains only 3- and 4-gluon vertices, but participants acknowledge that multiple connections between five gluons can still be made through propagators.
  • One participant mentions having solved the problem differently, implying a potential alternative approach to the original question.
  • Another participant expresses difficulty in finding an online source for the diagrams but suggests that drawing them is feasible despite the number of diagrams involved.

Areas of Agreement / Disagreement

Participants generally agree on the focus being tree-level diagrams and the limitations of the QCD Lagrangian. However, there is no consensus on the best method to compile or visualize these diagrams, and some uncertainty remains regarding the completeness of the approaches discussed.

Contextual Notes

The discussion does not resolve the challenge of listing all possible diagrams, and participants do not provide a definitive source for such diagrams. The conversation reflects varying levels of familiarity with the topic and different approaches to the problem.

earth2
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Hey folks,

you don't happen to know where i can find a list of all possible Feynman diagrams contributing to a 5-gluon-amplitude?

I am currently working on a comparison of beyond-feynman-graphs-techniques (colour-ordering, BCF, CSW, MHV,...) and old-school calculations using Feynman rules. My specific example is for tree-level 5-gluon scattering but i can't find a list of of possible Feynman diagrams...

Do you have an idea?

Regards,
earth2
 
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Hmmm, I think you may need to be more specific. If you allow loops, then there are an infinite number of contributing diagrams. Perhaps your question is slightly different from this?
 
Hey,

i mean only tree-level diagrams i.e. no loops.
 
earth2 said:
Hey,

i mean only tree-level diagrams i.e. no loops.

in the QCD lagrangian u only have 3 and 4 gluon vertex
 
ansgar said:
in the QCD lagrangian u only have 3 and 4 gluon vertex

Yes, no one doubts that. But that does not mean that there aren't several ways to connect five gluons via propagators, does it? Never you mind, i solved the problem differently. Thanks.
 
Hi earth2,

Sorry, I spoke with some people but couldn't find a place where the diagrams were listed online. Did you find a good source? I think it's not too hard to just draw them all, but there are quite a few.
 

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