Inclusive and exclusive measurements of $B$ decays to $χ_{c1}$ and $χ_{c2}$ at Belle

Abstract: We report inclusive and exclusive measurements for $\chi_{c1}$ and $\chi_{c2}$ production in $B$ decays. We measure $\mathcal{B}(B \to \chi_{c1} X)$= $(3.03 \pm 0.05(\mbox{stat}) \pm 0.24(\mbox{syst})) \times 10<sup>{-3}$ and $\mathcal{B}(B \to \chi_{c2} X)$= $(0.70 \pm 0.06(\mbox{stat}) \pm 0.10(\mbox{syst})) \times 10<sup>{-3}$. For the first time, $\chi_{c2}$ production in exclusive $B$ decays in the modes $B⁰ \to \chi_{c2}\pi^- K<sup>+$ and $$B⁺ \to \chi_{c2} \pi⁺ \pi^- K<sup>+$$ has been observed, along with first evidence for the $$B⁺ \to \chi_{c2} \pi⁺ K_S<sup>0$$ decay mode. For $\chi_{c1}$ production, we report the first observation in the $$B⁺ \to \chi_{c1} \pi⁺ \pi^- K<sup>+$$, $$B⁰ \to \chi_{c1} \pi⁺ \pi^- K_S<sup>0$$ and $$B⁰ \to \chi_{c1} \pi⁰ \pi^- K<sup>+$$ 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 $$B⁺ \to (\chi_{c1} \pi⁺ \pi^-) K<sup>+$$ decay mode. The reported results use $772 \times 10<sup>{6}$ $B\overline{B}$ events collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e<sup>+e<sup>-$ collider.