NEW SUPERNOVA CONSTRAINTS ON STERILE-NEUTRINO PRODUCTION

We consider the possibility that a light, sterile-neutrino species nu( S) can be produced by nu(e) scattering during the cooling of a proto-n eutron star. If we parametrize the sterile-neutrino production cross s ection by a parameter A as sigma(nu(e)X --> nu(S)X) = A sigma(nu(e) -- > nu(e)X), where X is an electron, neutron, or proton, we show that A Is constrained by limits to the conversion of nu(e) to nu(S) in the re gion between the sterile-neutrino trapping region and the electron-neu trino, trapping region. This consideration excludes values of A in the range 10(-4) less than or similar to A less than or similar to 10(-1) .