>>13355853It produced the photonic final states and that's all I care about as OP, not why it happens, not whether or not it violates QED, or anything else. Imagine you're someone who's never done particle physics before. Or say you're TAing a course to non-physics majors and you need to explain beta decay. Your average Joe doesn't fucking care about W's, quantum fields, gauges, and all that. To him all that matters is that a neutron decays into a proton, electron, and two neutrinos. This is the exact same argument here. Pretend like I somehow know QFT perfectly well while having no idea about the standard model or any decay other than nu -> nu gamma gamma. To me that interaction would be described by some effective Lagrangian similar to 4-Fermi theory.
You use vertex reconstruction ASSUMING that your theory is valid and you have it in front of your eyes, not the other way around. You said it yourself, you need to use Feynman diagrams, so you need to formulate a theory.
