A HQET Feynman Rule: QCD Interaction Vertex Explained

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The HQET Feynman rule for the QCD interaction vertex is expressed as igTijvμ/(1+slashed{v}), which is derived from the interaction between heavy quark propagators. The reasoning for the vector vμ is based on the heavy quark propagators being represented as (1+slashed{v})/(2v.k). There is a discussion about whether the vertex rule should align with standard QCD rules, with the only distinction being the heavy quark propagator. Additionally, users express frustration over the lack of LaTeX support in the discussion box for proper mathematical representation. The conversation emphasizes the need for clarity in the application of the vertex rule in the context of heavy quarks.
Elmo
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TL;DR
A slight confusion about HQET Feynman rules ,as stated in most texts.
Several texts state the vertex HQET Feynman rule as : igTijvμ\frac{1}{1+\slashed{v}} with the reasoning for vμ presented as being due to the QCD interaction vertex being between two heavy quark propagators, which are \frac{1+\slashed{v}}{2v.k}, giving :
vμ\frac{1+\slashed{v}}{2}=\frac{1+\slashed{v}}{2}γμ\frac{1+\slashed{v}}{2}.

So in general, shouldn't the vertex rule be the same as in QCD ? The only difference being the heavy quark propagator.
 
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and for some reason latex is not supported in this box, or am I missing something ?
 
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