Observation of B±→χc1π± and search for direct CP violation

Le résumé fourni par la source

We report the first observation of ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, a Cabibbo- and color-suppressed decay in a data sample of $386\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We observe $55\ifmmode\pm\else\textpm\fi{}10$ signal events with a statistical significance of $6.3\ensuremath{\sigma}$ including systematic uncertainties. The measured branching fraction and charge-asymmetry is $\mathcal{B}({B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})=(2.2\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and ${\mathcal{A}}_{\ensuremath{\pi}}=0.07\ifmmode\pm\else\textpm\fi{}0.18\ifmmode\pm\else\textpm\fi{}0.02$, respectively. We also determine the ratio $\mathcal{B}({B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})/\mathcal{B}({B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{K}^{\ifmmode\pm\else\textpm\fi{}})=(4.3\ifmmode\pm\else\textpm\fi{}0.8\ifmmode\pm\else\textpm\fi{}0.3)%$.

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