Semileptonic bc to cc baryon decay and heavy quark spin symmetry

We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons (Xi(('*))(bc)->Xi((*))(cc) and Omega(('*))(bc)->Omega((*))(cc)), in the limit m(b),m(c)>Lambda(QCD) and close to the zero-recoil point. The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor. We recover results derived previously by White and Savage in a manner which we think is more straightforward and parallels the method applied later to study B-c semileptonic decays. We further discuss the resemblance between the bc baryon decays and those of B-c mesons to eta(c) and J/psi mesons and comment on the relation between the slopes of the single functions describing each set of decays. Our results can straightforwardly be applied to the decays of bb baryons to bc baryons.