Inclusive and exclusive measurements ofBdecays toχc1andχc2at Belle
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Abstract
We report inclusive and exclusive measurements for ${\ensuremath{\chi}}_{c1}$ and ${\ensuremath{\chi}}_{c2}$ production in $B$ decays. We measure $\mathcal{B}(B\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}X)=(3.03\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.24(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $\mathcal{B}(B\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c2}X)=(0.70\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.10(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. For the first time, ${\ensuremath{\chi}}_{c2}$ production in exclusive $B$ decays in the modes ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c2}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}$ and ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c2}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}$ has been observed, along with first evidence for the ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c2}{\ensuremath{\pi}}^{+}{K}_{S}^{0}$ decay mode. For ${\ensuremath{\chi}}_{c1}$ production, we report the first observation in the ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}$, ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{K}_{S}^{0}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}$ decay modes. Using these decay modes, we observe a difference in the production mechanism of ${\ensuremath{\chi}}_{c2}$ in comparison to ${\ensuremath{\chi}}_{c1}$ in $B$ decays. In addition, we report searches for $X(3872)$ and ${\ensuremath{\chi}}_{c1}(2P)$ in the ${B}^{+}\ensuremath{\rightarrow}({\ensuremath{\chi}}_{c1}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}){K}^{+}$ decay mode. The reported results use $772\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected at the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider.