Elmo
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- TL;DR
- A confusion about the photon-W boson interaction term
This screenshot is from Quantum Field Theory by Mandl and Shaw, 2nd Edition.
I had a question about the vertex factor feynman rule (given below the daigram) of the photon and W+, W- interaction term. Its lagrangian density is given in the third and fourth line of (19.3 a)
What confuses me is the fact that this diagram shows all the momenta directed inwards. Is it the only possible way this coupling can exist or can we also show something like say, the W+ and W- boson momenta directed outwards from the vertex and photon coming inwards ? How will the vertex factor change in that case ? Is it simply a matter of flipping the signs of the momenta in the vertex factor expression ?
Also, is it possible to have a vertex where there is something like a Bremsstrahlung on a single W+ or W- line ?
![Feynman diagram with photon line labeled gamma (alpha) entering a vertex, with W+ (beta) and W- (gamma) lines leaving, momenta k1, k2, k3 marked, and the vertex factor ie[g^{αβ}(k1 - k2)^γ + g^{βγ}(k2 - k3)^α + g^{γα}(k3 - k1)^β] printed below.](https://www.physicsforums.com/attachments/screenshot-469-png.331894/ "Screenshot (469).png")
I had a question about the vertex factor feynman rule (given below the daigram) of the photon and W+, W- interaction term. Its lagrangian density is given in the third and fourth line of (19.3 a)
What confuses me is the fact that this diagram shows all the momenta directed inwards. Is it the only possible way this coupling can exist or can we also show something like say, the W+ and W- boson momenta directed outwards from the vertex and photon coming inwards ? How will the vertex factor change in that case ? Is it simply a matter of flipping the signs of the momenta in the vertex factor expression ?
Also, is it possible to have a vertex where there is something like a Bremsstrahlung on a single W+ or W- line ?
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