Self-consistency in models of neutrino scattering and fast flavor conversion

Understand

Several recent numerical studies have examined the effects of neutrino neutral-current scattering on fast flavor conversion (FFC).

• Those studies are in apparent conflict, with some finding enhancement of flavor conversion and others finding suppression.
• The ones that report enhancement all use homogeneous models, and we discuss in detail the self-consistency issues that they face as a result.
• We reproduce scattering-enhanced FFC in our own homogeneous calculations, showing that it occurs for both neutral- and charged-current scattering and that it is due to isotropization of the angular distributions over time.