Triply heavy baryons and heavy quark spin symmetry

Abstract

We study the semileptonic $b\ensuremath{\rightarrow}c$ decays of the lowest-lying triply heavy baryons made from $b$ and $c$ quarks in the limit ${m}_{b}$, ${m}_{c}\ensuremath{\gg}{\ensuremath{\Lambda}}_{\mathrm{QCD}}$ and close to the zero-recoil point. The separate heavy-quark spin symmetries strongly constrain the matrix elements, leading to single form factors for $ccb\ensuremath{\rightarrow}ccc$, $bbc\ensuremath{\rightarrow}ccb$, and $bbb\ensuremath{\rightarrow}bbc$ baryon decays. We also study the effects on these systems of using a $Y$-shaped confinement potential, as suggested by lattice QCD results for the interaction between three static quarks.