2024

Kainulainen, Kimmo; Parkkinen, Harri

We present quantum kinetic equations for neutrinos and derive Feynman rules for computing scattering rates involving coherent states. Our rules encompass both flavour- and particle-antiparticle coherence and allow writing down the scattering matrix elements and collision integrals with the same intuitive ease as with the usual non-coherent Feynman rules. Our results are useful for computing collision rates that arise routinely in the context of coherently mixing neutrinos with arbitrary masses. We give several explicit examples, including some collision integrals for coherently mixing neutrinos in supernovae.