Speaker
Sookyung Choi
(Gyeongsang)
Description
From a Dalitz plot analysis of $B \to K \pi^+ \psi'$ decays, we find a signal for $Z(4430)^+ \to \pi^+ \psi'$ with a mass $M = (4442^{+15}_{-12}{}^{+19}_{-13})$MeV/$c^2$, width $\Gamma = (107^{+86}_{-43}{}^{+74}_{-56})$ MeV, product branching fraction $\mathcal{B}(\bar{B}^0 \to K^- Z(4430)^+) \times \mathcal{B}(Z(4430)^+ \to \pi^+ \psi') = (3.2^{+1.8}_{-0.9}{}^{+5.3}_{-1.6}) \times 10^{-5}$, and significance of 6.4$\sigma$ that agrees with previous Belle measurements based on the same data sample. In addition, we determine the branching fraction $\mathcal{B}(B^0 \to K^*(892)^0 \psi') = (5.52^{+0.35}_{-0.32}{}^{+0.53}_{-0.58}) \times 10^{-4}$ and the fraction of $K^*(892)^0$ mesons that are longitudinally polarized $f_{L} = (44.8^{+4.0}_{-2.7}{}^{+4.0}_{-5.3})\%$. These results are obtained from a large data sample collected near the $\Upsilon(4S)$ resonance with the Belle detector
at the KEKB asymmetric energy $e^+ e^-$ collider.
The CDF collaboration recently reported a narrow structure $Y(4341)$ near the $J/\psi \phi$ threshold with a statistical significance of 3.8 $\sigma$. A similar study is performed in the $B \to J/\psi \phi K^+$ mode to verify whether or not this new structure is present in Belle data.
We also have searched for a charmonium-like state in the process $\gamma \gamma \to \omega J/\psi$ in the mass region, 3.9-4.2 GeV/$c^2$. This may be related to one or more of the three charmonium-like states reported in the similar mass region.
Primary author
Sookyung Choi
(Gyeongsang)
