Semileptonic form factors: A model-independent approach - art. no. 032006

We demonstrate that the B -->D-(*()) lv form factors can be accurately pred icted given the slope parameter rho (2) of the Isgur-Wise function. Only we ak assumptions, consistent with lattice results, on the wave function for t he light degrees of freedom are required to establish this result. We obser ve that the QCD and 1/m(Q) corrections can be systematically represented by an effective Isgur-Wise function of shifted slope. This greatly simplifies the analysis of semileptonic B decay. We also investigate what the availab le semileptonic data can tell us about lattice QCD and heavy quark effectiv e theory. A rigorous identity relating the form factor slope difference rho (2)(D*) - rho (2)(A1) to a combination of form factor intercepts is found. The identity provides a means of checking theoretically evaluated intercep ts with experiment.