Theoretical update on the model-independent determination of |V$_{cb}$| using heavy quark symmetry

In view of new precise measurements of the \bar B\to D^*\ell\,\bar\nu decay rate near zero recoil, we reconsider the theoretical uncertainties in the extraction of |\,V_{cb}| using heavy quark symmetry. In particular, we combine the Falk--Neubert estimate of 1/m_Q^2 corrections to the normalization of the hadronic form factor at zero recoil with sum rules derived by Shifman {\it et al}.\ to obtain a new prediction with less theoretical uncertainty. We also summarize the status of the calculation of short-distance corrections, and of the slope of the form factor at zero recoil. We find {\cal F}(1)=\eta_A\,\widehat\xi(1)=0.93\pm 0.03 and \widehat\varrho^2=0.7\pm 0.2. Combining this with the most recent experimental results, we obtain the model-independent value |\, V_{cb}|=0.040\pm 0.003.