Charged-current reactions in the supernova neutrino-sphere
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© 2015 American Physical Society. We calculate neutrino absorption rates due to charged-current reactions νe+n→e-+p and ν¯e+p→e++n in the outer regions of a newly born neutron star called the neutrino-sphere. To improve on recent work which has shown that nuclear mean fields enhance the νe cross section and suppress the ν¯e cross section, we employ realistic nucleon-nucleon interactions that fit measured scattering phase shifts. Using these interactions we calculate the momentum-, density-, and temperature-dependent nucleon self-energies in the Hartree-Fock approximation. A potential derived from chiral effective field theory and a pseudopotential constructed to reproduce nucleon-nucleon phase shifts at the mean-field level are used to study the equilibrium proton fraction and charged-current rates. We compare our results to earlier calculations obtained using phenomenological mean-field models and to those obtained in the virial expansion valid at low density and high temperature. In the virial regime our results are consistent with previous calculations, and at higher densities relevant for the neutrino-sphere, ρ 1012 g/cm3, we find the difference between the νe and ν¯e absorption rates to be larger than predicted earlier. Our results may have implications for heavy-element nucleosynthesis in supernovae, and for supernova neutrino detection.
author list (cited authors)
Rrapaj, E., Holt, J. W., Bartl, A., Reddy, S., & Schwenk, A.