Stellar collapse dynamics with neutrino flavor changing neutral currents

We perform one-zone simulations of the infall epoch of a presupernova stellar core in the presence of neutrino flavor changing scattering interactions. Our calculations give a self-consistent assessment of the relationship between flavor changing rates and the reduction in electron fraction and redistribution of initial electron lepton number among the neutrino flavors. We discuss and include in our calculations subnuclear density medium corrections for flavor changing scattering coherence factors. We find that flavor changing couplings ε>3x10-4 in either the νe↔νμ or νe↔ντ channels result in a dynamically significant reduction in the core electron fraction relatively soon after neutrino trapping and well before the core reaches nuclear matter density