First Simultaneous Determination of Inclusive and Exclusive |Vub|

Le résumé fourni par la source

The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element ${V}_{ub}$ using inclusive and exclusive decays is performed with the full Belle data set at the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance, corresponding to an integrated luminosity of $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We analyze collision events in which one $B$ meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic ${X}_{u}$ system of the semileptonic $b\ensuremath{\rightarrow}u\ensuremath{\ell}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ decay. We separate exclusive $B\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\ell}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ decays from other inclusive $B\ensuremath{\rightarrow}{X}_{u}\ensuremath{\ell}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ and backgrounds with a two-dimensional fit that utilizes the number of charged pions in the ${X}_{u}$ system and the four-momentum transfer ${q}^{2}$ between the $B$ and ${X}_{u}$ systems. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the $B\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\ell}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ form factor, we determine $|{V}_{ub}^{\mathrm{excl}}|=(3.78\ifmmode\pm\else\textpm\fi{}0.23\ifmmode\pm\else\textpm\fi{}0.16\ifmmode\pm\else\textpm\fi{}0.14)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $|{V}_{ub}^{\mathrm{incl}}|=(3.88\ifmmode\pm\else\textpm\fi{}0.20\ifmmode\pm\else\textpm\fi{}0.31\ifmmode\pm\else\textpm\fi{}0.09)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of $|{V}_{ub}^{\mathrm{excl}}|/|{V}_{ub}^{\mathrm{incl}}|=0.97\ifmmode\pm\else\textpm\fi{}0.12$ is compatible with unity.

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