Study of $\Lambda_b\to\Lambda\nu\bar{\nu}$ with Polarized Baryons
  We investigate the decay of $\Lambda_b\to\Lambda\nu\bar{\nu}$ with the polarized baryons of $\Lambda_b$ and $\Lambda$. With the most general hadronic form factors, we first study the decay branching ratio and then derive the longitudinal, normal and transverse polarizations of $\Lambda$ in terms of the spin unit vectors of $\Lambda_b$ and $\Lambda $ and the momentum of $\Lambda $. A polarization of $\Lambda_b$ is also discussed. 
Chuan-Hung Chen and C.Q. Geng