Factorization in color-favored B-meson decays to charm

Improved B meson decay data have permitted more incisive tests of factorization predictions. A concurrent benefit is the ability to constrain the Cabibbo-Kobayashi-Maskawa matrix element $|V_{\mathrm{cb}}|.$ Using a simultaneous fit to differential distributions $d\Gamma (B^0\to D^{\left(*\right)+}{l}^{-}{\overline{\nu }}_l{)/dq}^2$ and the rates for the color-favored decays $B^0\to D^{\left(*\right)+}({\pi }^{-},{\rho }^{-}{,a}_1^{-}),$ we find $|V_{\mathrm{cb}}|=0.0415\mathrm{}\pm \mathrm{0.0022.}$ The slope of the universal Isgur-Wise form factor is described by a parameter found to be ${\rho }^2=1.52\mathrm{}\pm \mathrm{0.11.}$ Taking the $D_s$ meson decay constant from the world average of direct measurements, we predict satisfactorily the branching ratios for $B^0\to D^{\left(*\right)+}{D}_s^{\left(*\right)-}.$ Ratios of helicity amplitudes for color-favored processes are also found to be in accord with predictions.