Polarization effects in tau production by neutrino
  We studied polarization effects in tau production by neutrino-nucleon scattering. Quasi-elastic scattering, $Delta$ resonance production and deep inelastic scattering processes are taken into account for the CERN-to-Gran Sasso projects. We show that the tau produced by neutrino has high degree of polarization, and its spin direction depends non-trivially on the energy and the scattering angle of tau in the laboratory frame. 
K. Hagiwara (KEK), K. Mawatari (Kobe U.), H. Yokoya (Hiroshima U. and   RIKEN)