The role of strange sea quarks on neutrino-nucleus reactions in Superkamiokande and in the supernova r-process

We study the influence of a strange axial vector form factor G_s of the nucleon on the neutrino-induced proton and neutron knockout of ¹⁶O. In particular, we calculate how much G_s≠0 might affect the recently proposed signal for supernova ν_μ and ν_τ neutrinos in the Superkamiokande detector. We discuss whether Superkamiokande might be able to determine the value of G_s in a hypothetical neutrino-beam experiment. Finally we comment on the possible effect G_s≠0 might have on neutrino-nucleus cross sections in the neutrino-driven wind model for the nuclear r-process. Received: 30 April 1998 / Revised version: 10 August 1998