Measurement of ratios of branching fractions and CP -violating asymmetries of B±→D*K± decays

Le résumé fourni par la source

We report a study of ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{*}{K}^{\ifmmode\pm\else\textpm\fi{}}$ decays with ${D}^{*}$ decaying to $D{\ensuremath{\pi}}^{0}$ or $D\ensuremath{\gamma}$, using $383\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\mathit{\ensuremath{\Upsilon}}(4S)$ resonance with the BABAR detector at the SLAC PEP-II $B$ Factory. The $D$ meson decays under study include a non-$CP$ mode $({K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}})$, $CP$-even modes $({K}^{\ifmmode\pm\else\textpm\fi{}}{K}^{\ensuremath{\mp}},{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}})$, and $CP$-odd modes $({K}_{S}^{0}{\ensuremath{\pi}}^{0},{K}_{S}^{0}\ensuremath{\phi},{K}_{S}^{0}\ensuremath{\omega})$. We measure ratios (${R}_{CP\ifmmode\pm\else\textpm\fi{}}^{*}$) of branching fractions of decays to $CP$ eigenmode states and to flavor-specific states as well as $CP$ asymmetries (${A}_{CP\ifmmode\pm\else\textpm\fi{}}^{*}$). These measurements are sensitive to the unitarity triangle angle $\ensuremath{\gamma}$. We obtain ${A}_{CP+}^{*}=\ensuremath{-}0.11\ifmmode\pm\else\textpm\fi{}0.09\ifmmode\pm\else\textpm\fi{}0.01$, ${R}_{CP+}^{*}=1.31\ifmmode\pm\else\textpm\fi{}0.13\ifmmode\pm\else\textpm\fi{}0.04$, and ${A}_{CP\ensuremath{-}}^{*}=0.06\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.02$, ${R}_{CP\ensuremath{-}}^{*}=1.10\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.04$, where the first error is statistical and the second error is systematic. Translating our results into an alternative parametrization, widely used for related measurements, we obtain ${x}_{+}^{*}=0.11\ifmmode\pm\else\textpm\fi{}0.06\ifmmode\pm\else\textpm\fi{}0.02$ and ${x}_{\ensuremath{-}}^{*}=0.00\ifmmode\pm\else\textpm\fi{}0.06\ifmmode\pm\else\textpm\fi{}0.02$. No significant $CP$-violating charge asymmetry is found in either the flavor-specific mode $D\ensuremath{\rightarrow}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ or in ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ decays.

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