Measurement of branching fraction ratios and CP asymmetries in B±→DCPK±

Le résumé fourni par la source

We report results on the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{\mathrm{CP}}{K}^{\ensuremath{-}}$ and its charge conjugate using a data sample of $85.4\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs recorded at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes are determined to be $\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{0}{K}^{\ensuremath{-}})/\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}})=0.077\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.006(\mathrm{syst}),$ $\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{1}{K}^{\ensuremath{-}})/\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{1}{\ensuremath{\pi}}^{\ensuremath{-}})=0.093\ifmmode\pm\else\textpm\fi{}0.018(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.008(\mathrm{syst})$ and $\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{2}{K}^{\ensuremath{-}})/\mathcal{B}{(B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{2}{\ensuremath{\pi}}^{\ensuremath{-}})=0.108\ifmmode\pm\else\textpm\fi{}0.019(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.007(\mathrm{syst})$ where the indices 1 and 2 represent the $CP=+1$ and $CP=\ensuremath{-}1$ eigenstates of the ${D}^{0}\ensuremath{-}{D}^{0}$ system, respectively. We find the partial-rate charge asymmetries for ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{\mathrm{CP}}{K}^{\ensuremath{-}}$ to be ${\mathcal{A}}_{1}=0.06\ifmmode\pm\else\textpm\fi{}0.19(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst})$ and ${\mathcal{A}}_{2}=\ensuremath{-}0.19\ifmmode\pm\else\textpm\fi{}0.17(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{syst}).$

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