Tau polarization in quasielastic charged-current neutrino(antineutrino)-nucleus scattering

The quasielastic charged-current (CC) tau neutrino (antineutrino)-nucleus scattering is considered. The dependence of tau polarization on nuclear-structure effects is discussed in detail. The description of the nucleus is based on the Mean-Field Theory (MFT). The ground state of nucleus is described using the Relativistic Fermi Gas model (FG). The effective mass is introduced as well as the ring Random Phase Approximation (RPA) effects are taken into account in the framework of relativistic meson-nucleon model. The Local Density Approximation (LDA) is used for the argon nucleus, having in mind possible application to the ICARUS experiment. The discussion concentrates on the threshold region where the $\tau^-$ can be unpolarized and the nuclear effects play an important role.