Computing the 1-loop Correction to the 3 Gluon Vertex with Non-Zero Quark Mass

[ParticleGrl]

Anyone know a reference in the literature that computes the correction to the 3 gluon vertex due to a quark loop with non-zero quark-mass?

 

[petergreat]

You mean a triangular quark loop at the center? I think this diagram vanishes. This amplitude = (trace of SU(3) generators of the gluons) * (QED photon 3-point function with a fermion loop). The latter vanishes because in QED the photon 3-point function vanishes. I may have made a mistake, so please correct me.

 

[ParticleGrl]

You mean a triangular quark loop at the center? I think this diagram vanishes. This amplitude = (trace of SU(3) generators of the gluons) * (QED photon 3-point function with a fermion loop). The latter vanishes because in QED the photon 3-point function vanishes. I may have made a mistake, so please correct me.

The QED three point function vanishes because its a sum of two loops, one cancels against the other. In QCD, you get tr[t^a t^b t^c] - tr[t^a t^c t^b], which is proportional to f^(a,b,c), as you'd expect.

 

[Dickfore]

Maybe this can help:

arXiv:hep-ph/9806522v1[/URL]