Study of ${\Lambda }_b\to \Lambda \nu \bar{\nu }$ with Polarized Baryons

Abstract

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.

Comments: 19 pages, 8 Figures, LaTex file, to be published in PRD