A. Zee, Quantum Field Theory in a Nutshell · Problem II.5.2

Field Theory Redux

Physics — QFT

Problem

Applying the Feynman rules for the vector theory (22) show that the amplitude for the diagram in figure II.5.3 is given by

(ie)^2 i^2 \int \frac{d^4k}{(2\pi)^4} \frac{1}{k^2 - \mu^2} \left(\frac{k_\mu k_\nu}{\mu^2} - g_{\mu\nu}\right) \bar{u}(p)\gamma^\nu \frac{\not{p} + \not{k} + m}{(p + k)^2 - m^2} \gamma^\mu u(p)