Dynamics of fast neutrino flavor conversions with scattering effects: a detailed analysis

Understand

We calculate fast conversions of two flavor neutrinos by considering Boltzmann collisions of neutrino scatterings.

• In an idealized angular distribution of neutrinos with electron-lepton number crossing, we find that the collision terms of the neutrino scattering enhance the transition probability of fast flavor conversions as in the previous study.
• We analyze the dynamics of fast flavor conversions with collisions in detail based on the motion of polarization vectors in cylindrical coordinate analogous to a pendulum motion.
• The phase of the all polarization vector synchronizes in the linear evolution, and the phase deviation from the Hamiltonian governs the conversion of neutrino flavor.