$\Lambda_b$ Decays into $\Lambda$-Vector
  A complete study of the angular distributions of the processes, $\Lambda_b \to {\Lambda} V(1^-)$, with $\Lambda \to p {\pi}^-$ and $V (J/{\Psi}) \to {\ell}^+ {\ell}^-$ or $V ({\rho}^0,\omega) \to {\pi}^+ {\pi}^-,$ is performed.   Emphasis is put on the initial $\Lambda_b$ polarization produced in the proton-proton collisions. The polarization density-matrices as well as angular distributions are derived and help to construct T-odd observables which allow us to perform tests of both Time-Reversal and CP violation. 
Z.J. Ajaltouni (LPC, Universite Blaise Pascal), E. Conte (LPC,   Universite Blaise Pascal) and O. Leitner (ECT*)