Neutrino luminosity and matter-induced modification of collective neutrino flavor oscillations in supernovae

Abstract

We present the first calculations of self-coupled neutrino flavor oscillations with time integrated luminosities and energy spectra for the neutronization burst of an $\mathrm{O}\ensuremath{-}\mathrm{Ne}\ensuremath{-}\mathrm{Mg}$ core-collapse supernova. These calculations allow us to gauge the effects of time varying neutrino luminosity and of the bump in the electron number density profile at the base of the hydrogen envelope in $\mathrm{O}\ensuremath{-}\mathrm{Ne}\ensuremath{-}\mathrm{Mg}$ core-collapse supernovae. The bump allows a significant fraction of the low-energy ${\ensuremath{\nu}}_{e}$ to survive by rendering their flavor-evolution nonadiabatic. Increasing the luminosity of the neutronization burst shifts the bump-affected ${\ensuremath{\nu}}_{e}$ to lower energy with reduced survival probability. Similarly, lowering the luminosity shifts the bump-affected neutrinos to higher energies. While these low-energy neutrinos lie near the edge of detectability, the population of bump-affected neutrinos has direct influence on the spectral swap formation in the neutrino signal at higher energies.