SELF-CONSISTENT APPROACH TO NEUTRAL-CURRENT PROCESSES IN SUPERNOVA CORES

The problem of neutral-current processes (neutrino scattering, pair em ission, pair absorption, axion emission, etc.) in a nuclear medium can be separated into an expression representing the phase space of the w eakly interacting probe, and a set of dynamic structure functions of t he medium. For a nonrelativistic medium we reduce the description to t wo structure functions S-A(omega) and S-V(omega) of the energy transfe r, representing the axial-vector and vector interactions. S-V is well determined by the single-nucleon approximation while S-A may be domina ted by multiply interacting nucleons. Unless the shape of S-A(omega) c hanges dramatically at high densities, scattering processes always dom inate over pair processes for neutrino transport or the emission of ri ght-handed states. Because the emission of right-handed neutrinos and axions is controlled by the same medium response functions, a consiste nt constraint on their properties from consideration of supernova cool ing should use the same structure functions for both neutrino transpor t and exotic cooling mechanisms.