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Theoretical uncertainties in the extraction of |V$_{cb}$| from $\overline{B}$ --> D$*$l$\overline{\nu}$ decays near zero recoil

I discuss the theoretical uncertainties in the extraction of |\, V_{cb}| from a measurement of the \bar B\to D^*\ell\,\bar\nu decay rate close to zero recoil. In particular, I combine previous estimates of the 1/m_Q^2 corrections to the normalization of the hadronic form factor at zero recoil with s...

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Detalles Bibliográficos
Autor principal: Neubert, Matthias
Lenguaje:eng
Publicado: 1994
Materias:
Acceso en línea:http://cds.cern.ch/record/268585
Descripción
Sumario:I discuss the theoretical uncertainties in the extraction of |\, V_{cb}| from a measurement of the \bar B\to D^*\ell\,\bar\nu decay rate close to zero recoil. In particular, I combine previous estimates of the 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 uncertainty. I also give a prediction for the slope of the form factor \widehat\xi(w) at zero recoil: \widehat\varrho^2=0.7\pm 0.2. Using the most recent experimental results, I obtain the model-independent value |\, V_{cb}|=0.0395\pm 0.0030.