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 ${\nu }_{\mathit{e}}$ with ${\nu }_{\mathrm{\tau }}$ (or ${\nu }_{\mathrm{\mu }}$) possessing cosmologically significant masses (1 to 100 eV). We conclude that the ${\nu }_{\mathrm{\tau }}$(${\nu }_{\mathrm{\mu }}$)-${\nu }_{\mathit{e}}$ vacuum mixing angle must satisfy ${\sin }^2$2θ<${10}^{\mathrm{-}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.