Hyperfine Interactions in Charm and Bottom Systems

Hyperfine interactions in the light meson and baryon sectors are generalized to the charm and bottom systems. It is pointed out that an attempt to increase the value of the wave function at the origin to account for the unusual ratio of $\Lambda_{b}$ to the $B^0$ lifetimes could spoil the good agreement among the baryon and meson hyperfine mass-splitting. Including spin effects and taking phase space differences into account we predict that the decay rate of the $\Lambda_{b}$ can be increased relative to that of the $B^0$ meson by about 7%.