A HQET Feynman Rule: QCD Interaction Vertex Explained

Elmo
Messages
37
Reaction score
6
TL;DR Summary
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.
 
Last edited:
Physics news on Phys.org
and for some reason latex is not supported in this box, or am I missing something ?
 

Thread 'Toponium Discovered'

Toponium is a hadron which is the bound state of a valance top quark and a valance antitop quark. Oversimplified presentations often state that top quarks don't form hadrons, because they decay to bottom quarks extremely rapidly after they are created, leaving no time to form a hadron. And, the vast majority of the time, this is true. But, the lifetime of a top quark is only an average lifetime. Sometimes it decays faster and sometimes it decays slower. In the highly improbable case that...
View full post »

Thread 'Dirac-Delta from Normalization of Continuous Eigenfunctions'

I'm following this paper by Kitaev on SL(2,R) representations and I'm having a problem in the normalization of the continuous eigenfunctions (eqs. (67)-(70)), which satisfy \langle f_s | f_{s'} \rangle = \int_{0}^{1} \frac{2}{(1-u)^2} f_s(u)^* f_{s'}(u) \, du. \tag{67} The singular contribution of the integral arises at the endpoint u=1 of the integral, and in the limit u \to 1, the function f_s(u) takes on the form f_s(u) \approx a_s (1-u)^{1/2 + i s} + a_s^* (1-u)^{1/2 - i s}. \tag{70}...
View full post »

Similar threads

I No "i" in the Triple gluon vertex Feynman Rule
Replies
8
Views
2K
A Renormalisation of the Fermionic triangle loop
Replies
1
Views
2K
A Heavy Quark Propagators in HQET
Replies
1
Views
1K
I Matrix Elements via Feynman Diagrams
Replies
1
Views
3K
I Calculating 2nd Order Scattering Amplitude: Feynman Diagrams
Replies
6
Views
3K
I Glueballs Observed For The First Time
Replies
10
Views
3K
Connected graphs and phi^4 interacting theory
Replies
2
Views
2K
Cross Section: Quark-Gluon vs. Quark-Photon
Replies
2
Views
3K
QCD Feynman Diagrams: Understanding Particle Interactions
Replies
7
Views
3K
Heavy sterile neutrino decay into Z bosons. (Feynman Diagram)
Replies
3
Views
4K

Hot Threads

Recent Insights

Back
Top