A HQET Feynman Rule: QCD Interaction Vertex Explained

Elmo
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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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