QFD - flavourdynamics
https://en.wikipedia.org/wiki/Weak_interaction
For example, beta decay of a neutron transforms it into a proton by the emission of an electron accompanied by an antineutrino; or, conversely a proton is converted into a neutron by the emission of a positron with a neutrino in so-called positron emission
https://en.wikipedia.org/wiki/Radioactive_decay
Fermi’s Theory of Beta Decay: A First Attempt at Electroweak Unification
mapping four fermion vertex (Fermi) to usual two-refmion-Wboson vertex
- Fermi beta decay theory, highlighting its analogies with the spectroscopic theory
and the similarity of the formalism with the modern electroweak theory.
....
which is compared with the emission of a photon by an atomic electron that decays from an excited state to a lower energetic level