Note on the slope parameter of the baryonic Λb→Λc Isgur-Wise function

Using the framework of the Heavy Quark Effective Theory we have re-analyzed the Isgur-Wise function describing semileptonic Λb→Λc decays in the QCD sum rule approach. The slope parameter of the Isgur-Wise function is found to be ρ2=1.35±0.13, which is consistent with an experimental measurement and a lattice calculation. To O(1/mb,1/mc) of the heavy quark expansion the integrated Λb decay width is used to extract the CKM matrix element Vcb for which we obtain a value of |Vcb|=0.041±0.004±0.001 in excellent agreement with the value of |Vcb| determined from semileptonic B→D∗ decays.