Supernova bound on keV-mass sterile neutrinos reexamined
Abstract
Active-sterile neutrino mixing is strongly constrained for ms > 100 keV to avoid excessive energy losses from supernova cores. For smaller ms, matter effects suppress the effective mixing angle except for a resonant range of energies where it is enhanced. We study the case of tau-s-mixing where a tau-tau asymmetry builds up due to the strong excess of s over s emission or vice versa, reducing the overall emission rate. In the warm dark matter range ms < 10 keV the mixing angle is essentially unconstrained.
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