Measurement of the form factors of the decay B0 -> D*- l+ nu and determination of the CKM matrix element |Vcb|
This article describes a determination of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar from the decay B-0 -> D*(-) l(+) v(l) using 711 fb(-1) of Belle data collected near the Y(4S) resonance. We simultaneously measure the product of the form factor normalization F(1) and the matrix element vertical bar V-cb vertical bar as well as the three parameters rho(2), R-1(1) and R-2(1), which determine the form factors of this decay in the framework of the heavy quark effective theory. The results, based on about 120 000 reconstructed B-0 -> D*(-) l(+) v(l) decays, are rho(2) = 1.214 +/- 0.034 +/- 0.009, R-1(1) = 1.401 +/- 0.034 +/- 0.018, R-2(1) = 0.864 +/- 0.024 +/- 0.008 and F(1)vertical bar V-cb vertical bar = (34.6 +/- 0.2 +/- 1.0) x 10(-3). The branching fraction of B-0 -> D*(-) l(+) v(l) is measured at the same time; we obtain a value of B-0 -> D*(-) l(+) v(l) = (4.58 +/- 0.03 +/- 0.26)%. The errors correspond to the statistical and systematic uncertainties. These results give the most precise determination of the form factor parameters and F(1)vertical bar V-cb vertical bar to date. In addition, a direct, model-independent determination of the form factor shapes has been carried out.