A. Burrows et Rf. Sawyer, EFFECTS OF CORRELATIONS ON NEUTRINO OPACITIES IN NUCLEAR-MATTER, Physical review. C. Nuclear physics, 58(1), 1998, pp. 554-571
Including nucleon-nucleon correlations due to both Fermi statistics an
d nuclear forces, we have developed a general formalism for calculatin
g the neutral-current neutrino-nucleon scattering rates in nuclear mat
ter. We derive corrections to the dynamic structure factors due to bot
h density and spin correlations and find that neutrino-nucleon scatter
ing rates are suppressed by large factors around and above nuclear den
sity. Hence, in particular for the nu(mu) and nu(tau) neutrinos, but a
lso for the nu(e) neutrinos, supernova cores are more ''transparent''
than previously thought. The many-body corrections increase with densi
ty, decrease with temperature, and are roughly independent of incident
neutrino energy. In addition, we find that the spectrum of energy tra
nsfers in neutrino scattering is considerably broadened by the interac
tions in the medium. An identifiable component of this broadening come
s from the absorption and emission of quanta of collective modes akin
to the Gamow-Teller and giant dipole resonances in nuclei (zero sound;
spin sound), with Cerenkov kinematics. Under the assumption that both
the charged-current and the neutral-current cross sections are decrea
sed by many-body effects, we calculate a set of ad hoc protoneutron st
ar cooling models to gauge the potential importance of the new opaciti
es to the supernova itself. While the early luminosities are not alter
ed, the luminosities after many hundreds of milliseconds to seconds ca
n be increased by factors that range from 10 to 100 %. Such enhancemen
ts may have a bearing on the efficacy of the neutrino-driven supernova
mechanism, the delay to explosion, the energy of the explosion, and t
he strength and relative role of convective overturn at late times. Ho
wever, the actual consequences, if any, of these new neutrino opacitie
s remain to be determined.