Branching fraction measurement of B¯0→D(*)+π− and B−→D(*)0π− and isospin analysis of B¯→D(*)π decays

Le résumé fourni par la source

Using $65\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\mathit{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}B\overline{B}$ events collected with the BABAR detector at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ storage ring at the Stanford Linear Accelerator Center, we measure the color-favored branching fractions $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(2.55\ifmmode\pm\else\textpm\fi{}0.05\ifmmode\pm\else\textpm\fi{}0.16)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{*+}{\ensuremath{\pi}}^{\ensuremath{-}})=(2.79\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.17)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}})=(4.90\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.22)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*0}{\ensuremath{\pi}}^{\ensuremath{-}})=(5.52\ifmmode\pm\else\textpm\fi{}0.17\ifmmode\pm\else\textpm\fi{}0.42)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, where the first error is statistical and the second is systematic. With these results and the current world average for the branching fraction for the color-suppressed decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{(*)0}{\ensuremath{\pi}}^{0}$, the cosines of the strong phase difference $\ensuremath{\delta}$ between the $I=1/2$ and $I=3/2$ isospin amplitudes are determined to be $\mathrm{cos}\ensuremath{\delta}={0.872}_{\ensuremath{-}0.007\ensuremath{-}0.029}^{+0.008+0.031}$ for the $\overline{B}\ensuremath{\rightarrow}D\ensuremath{\pi}$ process and $\mathrm{cos}\ensuremath{\delta}={0.924}_{\ensuremath{-}0.017\ensuremath{-}0.054}^{+0.019+0.063}$ for the $\overline{B}\ensuremath{\rightarrow}{D}^{*}\ensuremath{\pi}$ process. Under the isospin symmetry, the results for $\mathrm{cos}\ensuremath{\delta}$ suggest the presence of final-state interactions in the $D\ensuremath{\pi}$ system.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.