B --> D (D*) form-factors in a Bethe-Salpeter model

We calculate the form factors for the semileptonic decays of the B meson to D and D{sup {asterisk}} mesons in a Bethe-Salpeter model. We show that our model is consistent with the constraints of heavy quark effective theory (HQET) and we extract the matrix elements that represent the 1/m{sub Q} corrections to the form factors in HQET. We obtain {bar {Lambda}}{approximately}0.55 GeV which is consistent with QCD sum rules but higher than its estimate in nonrelativistic quark model calculations. With available data, we obtain V{sub cb}=(31.9{plus_minus}1.4){times}10{sup {minus}3}. {copyright} {ital 1997} {ital The American Physical Society}