The influence of collective neutrino oscillations on a supernova r-process

TL;DR

This study investigates how collective neutrino oscillations in supernovae influence the r-process nucleosynthesis, emphasizing the importance of accurate multiangle modeling over simpler approximations.

Contribution

It demonstrates that precise multiangle modeling of collective neutrino oscillations significantly affects r-process yield predictions in supernovae.

Findings

Multiangle treatment yields more accurate r-process predictions.

Oscillation effects depend on neutrino flux details and mass hierarchy.

Astrophysical conditions critically influence oscillation impacts.

Abstract

Recently, it has been demonstrated that neutrinos in a supernova oscillate collectively. This process occurs much deeper than the conventional matter-induced MSW effect and hence may have an impact on nucleosynthesis. In this paper we explore the effects of collective neutrino oscillations on the r-process, using representative late-time neutrino spectra and outflow models. We find that accurate modeling of the collective oscillations is essential for this analysis. As an illustration, the often-used "single-angle" approximation makes grossly inaccurate predictions for the yields in our setup. With the proper multiangle treatment, the effect of the oscillations is found to be less dramatic, but still significant. Since the oscillation patterns are sensitive to the details of the emitted fluxes and the sign of the neutrino mass hierarchy, so are the r-process yields. The magnitude of the effect also depends sensitively on the astrophysical conditions - in particular on the interplay between the time when nuclei begin to exist in significant numbers and the time when the collective oscillation begins. A more definitive understanding of the astrophysical conditions, and accurate modeling of the collective oscillations for those conditions, is necessary.