In a previous article, it has been proved under the framework of chiral soliton model that the same Isgur–Wise form factor describes the semileptonic Λb → Λc and Σ (∗) b → Σ (∗) c decays in the large Nc limit. It is shown here that this result is in fact independent of the chiral soliton model and is solely the consequence of the spin-flavor SU(4) symmetry… (More)