Impact of active-sterile neutrino mixing on supernova explosion and nucleosynthesis

We show that for the active-sterile flavor mixing parameters suggested by the reactor neutrino anomaly, substantial nu(e)-nu(s) and (nu) over bar (e)-(nu) over bar (s) conversion occurs in regions with an electron fraction of approximate to 1/3 near the core of an 8.8M(circle dot) electron-capture supernova. We explicitly include the feedback of such conversion on the evolution of the electron fraction in supernova ejecta. Compared to the case without such conversion, the neutron richness of the ejecta is enhanced to allow production of elements from Sr, Y, and Zr up to Cd in broad agreement with observations of the metal-poor star HD 122563 for a wide range of mixing parameters. Active-sterile flavor conversion can also strongly suppress neutrino heating at times when it is important for the revival of the shock. Our results suggest that simulations of a supernova explosion and the associated nucleosynthesis may be used to constrain active-sterile mixing parameters in combination with neutrino experiments and cosmological considerations.