A comprehensive description of a polarized positron project is presented in terms of physics motivations for utilizing a polarized positron in electron}positron collider experiments, a proof-of-principle experiment and a conceptual design of a polarized positron source for the future linear collider JLC. In order to verify a proposed method of creating highly polarized positron beams via succes...

In preparation for a set of hydrodynamical simulations of core-collapse supernovae and protoneutron star winds, we investigate the rates of production and thermalization of νμ and ντ neutrinos in dense nuclear matter. Included are contributions from electron scattering, electron-positron annihilation, nucleon-nucleon bremsstrahlung, and nucleon scattering. We find that nucleon scattering domina...