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