Charged current neutrino interactions in core-collapse supernovae in a virial expansion

Abstract

Core-collapse supernovae may depend sensitively on charged current neutrino interactions in warm, low density neutron rich matter. A proton in neutron rich matter is more tightly bound than is a neutron. This energy shift ΔU increases the electron energy in ν_e + n --> p + e, increasing the available phase space and absorption cross section. Likewise ΔU decreases the positron energy in \bar ν_e + p --> n + e^+, decreasing the phase space and cross section. We have calculated ΔU using a model independent virial expansion and we find ΔU is much larger, at low densities, than the predictions of many mean field models. Therefore ΔU could have a significant impact on charged current neutrino interactions in supernovae. Preliminary simulations of the accretion phase of core-collapse supernovae find that ΔU increases \bar ν_e energies and decreases the ν_e luminosity.

8 pages, 4 figures, minor corrections, Phys. Rev. C in press