# The 2009 Europhysics Conference on High Energy Physics

Jul 16 – 22, 2009
Kraków, Poland
Europe/Warsaw timezone

## Charmonium-like particles at Belle

Jul 16, 2009, 12:05 PM
25m
Exhibition room B (Kraków, Poland)

### Exhibition room B

#### Kraków, Poland

The Auditorium Maximum of the Jagiellonian University 33 Krupnicza Street 31-123 Kraków

### 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)

 Slides