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Dear PF,

I was reading one paper and trying to derive Feynman rules for some vertices, but I could not get the same result as given in paper, as a guideline I use ‘t Hooft’s diagrammar and the same is given in appendices of Cheng and Lee – Gauge Theory of elementary particle physics. I attach extract from one Arxiv paper, extract from diagrammar and what I was trying to write.

Could you please have a look and advise me what I do wrong?

Thank you in advance.

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# Problem with Feynman Rule for Vertices

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