We investigate the rates of production and thermalization of vμ and vτ neutrinos at temperatures and densities relevant to core-collapse supernovae and protoneutron stars. Included are contributions from electron scattering, electron-positron annihilation, nucleon-nucleon bremsstrahlung, and nucleon scattering. For the scattering processes, in order to incorporate the full scattering kinematics at arbitrary degeneracy, the structure function formalism developed by Reddy, Prakash, and Lattimer [Phys. Rev. D 58, 013009 (1998)] and Burrows and Sawyer [Phys. Rev. C 58, 554 (1998)] is employed. Furthermore, we derive formulas for the total and differential rates of nucleon-nucleon bremsstrahlung for arbitrary nucleon degeneracy in asymmetric matter. We find that electron scattering dominates nucleon scattering as a thermalization process at low neutrino energies (ε v ≲ 10 MeV), but that nucleon scattering is always faster than or comparable to electron scattering above ε v ≃ 10 MeV. In addition, for ρ ≳ 1013 g cm-3, T ≲ 14 MeV, and neutrino energies ≲60 MeV, nucleon-nucleon bremsstrahlung always dominates electron-positron annihilation as a production mechanism for vμ and vτ neutrinos.
|Original language||English (US)|
|Number of pages||3222198|
|Journal||Physical Review C - Nuclear Physics|
|State||Published - Sep 2000|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics