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 ν̅_ e + p → n + e+, decreasing the phase space and cross section. We have calculated ΔU using a model-independent virial expansion and we find that 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 ν̅ _e energies and decreases the ν_e luminosity.

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