B-]D(D-ASTERISK) FORM-FACTORS IN A BETHE-SALPETER MODEL

We calculate the form factors for the semileptonic decays of the B mes on to D and D mesons in a Bethe-Salpeter model. We show that our mode l is consistent with the constraints of heavy quark effective theory ( HQET) and we extract the matrix elements that represent the I/m(Q) cor rections to the form factors in HQET. We obtain <(Lambda)over bar>-0.5 5 GeV which is consistent with QCD sum rules but higher than its estim ate in nonrelativistic quark model calculations. With available data, we obtain V-cb=(31.9+/-1.4)x10(-3).