Observation of $X(3872)$ in $B to X(3872) Kpi$ decays

We report the first observation of $B^0 to X(3872) (K^{+}pi^{-})$ and evidence for $B^+ to X(3872) (K^{0}pi^{+})$. We measure the product of branching fractions for the former to be ${cal B}(B^0 to X(3872) (K^+ pi^-)) times {cal B}(X(3872) to J/psi pi^+ pi^-) = (7.9 pm 1.3(mbox{stat.})pm 0.4(mbox{syst.})) times 10^{-6}$ and find that $B^{0}to X(3872) K^{*}(892)^{0}$ does not dominate the $B^{0}to X(3872)K^{+}pi^{-}$ decay mode. We also measure ${cal B}(B^+ to X(3872) (K^0 pi^+)) times {cal B}(X(3872) to J/psi pi^+ pi^-) = (10.6 pm 3.0(mbox{stat.}) pm 0.9(mbox{syst.})) times 10^{-6}$. This study is based on the full data sample of 711~fb$^{-1}$ ($772times 10^6 Bbar B$ pairs) collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB collider.

Evidence of a new narrow resonance decaying to $chi_{c1}gamma$ in $B to chi_{c1} gamma K$

We report measurements of $B to chi_{c1} gamma K$ and $chi_{c2} gamma K$ decays using $772 times 10^{6}$ $Bbar{B}$ events collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Evidence of a new resonance in the $chi_{c1} gamma$ final state is found with a statistical significance of $3.8 sigma$. This state has a mass of $3823.1 pm 1.8 {(stat)} pm 0.7 {(syst)}$ MeV/$c^2$, a value that is consistent with theoretical expectations for the previously unseen $1^3 D_2$ $cbar{c}$ meson. We find no other narrow resonance and set upper limits on the branching fractions of the $X(3872) to chi_{c1} gamma$ and $chi_{c2} gamma$ decays.

Observation of $X(3872)to J/psi gamma$ and search for $X(3872)topsigamma$ in B decays

We report a study of $Bto (J/psi gamma) K$ and $Bto (psi gamma)K$ decay modes using $772times 10^{6}$ $Bbar{B}$ events collected at the Upsilon(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. We observe $X(3872) to J/psi gamma$ and report the first evidence for $chi_{c2} to J/psi gamma$ in $Bto (X_{cbar{c}}gamma) K$ decays, while in a search for $X(3872) to psi gamma$ no significant signal is found. We measure the branching fractions, $mathcal{B}(B^{pm} to X(3872) K^{pm}) mathcal{B}(X(3872) to J/psigamma)$ $=$ $(1.78^{+0.48}_{-0.44}pm 0.12)times 10^{-6}$, $mathcal{B} (B^{pm} tochi_{c2} K^{pm})$$=$ $(1.11^{+0.36}_{-0.34} pm 0.09) times 10^{-5}$, $mathcal{B}(B^{pm} to X(3872) K^{pm}) mathcal{B}(X(3872) to psigamma)$ $<$ $3.45times 10^{-6}$ (upper limit at 90% C.L.) and also provide upper limits for other searches.