I'm trying to figure out where symmetry breaking occurs in Feynman diagrams. I'm just free wheeling here, correct me where needed. But as I understand it, when you have a Feynman diagram where there is an interaction of one particle which decays to others, the incoming particle may obey one symmetry of the SM, but the outgoing particles may have a different symmetry of the SM (I can't think of an example at the moment). But that process of decay is an example of symmetry breaking, is this correct? Thank you.