| Abstract |
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We present a combined measurement of the Cabibbo-Kobayashi-Maskawa
matrix element |Vcb| and of the parameters rho^2, R_1, and
R_2, which fully characterize the form factors of the B0 -> D*-l^+nu_l
decay in the framework of HQET, based on a sample of about 52,800
B0 -> D*-l^+nu_l decays recorded by the BABAR detector.
The kinematical information of the fully reconstructed decay is used
to extract the following values for the parameters (where the first
errors are statistical and the second systematic):
rho^2 = 1.156 +- 0.094 +- 0.028, R_1 = 1.329 +- 0.131 +-
0.044, R_2 = 0.859 +- 0.077 +- 0.022, F(1)|Vcb| = (35.03 +- 0.39 +- 1.15) x 10^-3
By combining these measurements with the previous BABAR
measurements of the form factors which employs a different technique on a partial
sample of the data, we improve the statistical
accuracy of the measurement, obtaining:
rho^2 = 1.179 +- 0.048 +- 0.028,
R_1 = 1.417 +- 0.061 +- 0.044,
R_2 = 0.836 +- 0.037 +- 0.022, $ and $
F(1)|Vcb| = (34.68 +- 0.32 +- 1.15) x 10^{-3}.$
Using the lattice calculations for the axial form factor F(1),
we extract |Vcb| =(37.74 +- 0.35 +- 1.25 +- ^1.23_1.44 ) x 10^-3,
where the third error is due to the uncertainty in F(1).
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