Semileptonic bc to cc and bb to bc Baryon Decays and Heavy Quark Spin Symmetry

We study the semileptonic decays of the lowest-lying $bc$ baryons to the lowest-lying $cc$ baryons ($\Xi_{bc}^{(\prime*)}\to \Xi_{cc}^{(*)}$ and $\Omega_{bc}^{(\prime*)}\to \Omega_{cc}^{(*)}$), in the limit $m_b, m_c \gg \Lambda_\mathrm{QCD}$ 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 also show how these constraints can be used to test the validity of different quark model calculations. $bb$ to $bc$ baryon decays are also discussed.