Measurements of the Semileptonic Decays (bar B) → D(ell)(bar ν) and (bar B) → D*(ell)(bar ν) Using a Global Fit to DX(ell)(bar ν) Final States

Semileptonic (bar B) decays to DX(ell)(bar ν) ((ell) = e or μ) are selected by reconstructing D0(ell) and D+(ell) combinations from a sample of 230 million Υ(4S) → B(bar B) decays recorded with the BABAR detector at the PEP-II e+e- collider at SLAC. A global fit to these samples in a 3-dimensional space of kinematic variables is used to determine the branching fractions Β(B- → D0(ell)(bar ν)) = 2.36 ± 0.03 ± 0.12% and Β(B- → D*0(ell)(bar ν)) = (5.37 ± 0.02 ± 0.21)% where the errors are statistical and systematic, respectively. The fit also determines form factor parameters in a HQET-based parameterization, resulting in ρD2 = 1.22 ± 0.04 ± 0.07 for (bar B) → D(ell)(bar ν) and ρD*2 = 1.21 ± 0.02 ± 0.07 for (bar B) → D*(ell)(bar ν). These values are used to obtain the product of the CKM matrix element |Vcb| times the form factor at the zero recoil point for both (bar B) → D(ell)(bar ν) decays, G(1)|Vcb| = (43.8 ± 0.8 ± 2.3) x 10-3, and for (bar B) → D*(ell)(bar ν) decays, F(1)|Vcb| = (35.7 ± 0.2 ± 1.2) x 10-3