Connection between flavor-mixing of cosmologically significant neutrinos and heavy element nucleosynthesis in supernovae

We use heavy element nucleosynthesis from supernovae to probe the mixing of νe with ντ (or νμ) possessing cosmologically significant masses (1 to 100 eV). We conclude that the ντ(νμ)-νe vacuum mixing angle must satisfy sin22θ<10-5, in order to ensure that r-process heavy elements can be produced in neutrino-heated supernova ejecta. Mixing at a level exceeding this limit precludes r-process nucleosynthesis in this site.