The semileptonic decay of spin-½ baryons is examined in the spectator-quark model, with special attention given to ${\Lambda }_b\to {\Lambda }_{c}e\nu$ and ${\Omega }_b\to {\Omega }_{c}e\nu$. The polarization of the virtual $W$ and of the daughter baryon is also considered, along with the joint angular distribution between the charged lepton and the daughter-baryon polarization vector. The ${\Lambda }_b$ decays with about equal mixtures of transverse to longitudinal $W$ polarization while the ${\Omega }_b$ decays with predominately longitudinal $W$ polarization. These reactions are representative of two qualitatively different classes: decays involving baryons whose spectators are spin singlets and those whose spectators are spin triplets.

• Received 5 October 1990

DOI:https://doi.org/10.1103/PhysRevD.43.2939