Search

We search for the $\psi(4S)$ state in $B^\pm \ra \eta J/\psi K^\pm$ and $e^+e^- \ra \eta J/\psi$ based on the Belle measurements with the assumed mass $M=(4230\pm8)$ MeV/$c^2$ and width $\Gamma=(38\pm12)$ MeV. No significant signal is observed in the $\eta J/\psi$ mass spectra. The 90\% confidence level upper limit on the product branching fraction $\BR(B^\pm \ra \psi(4S)K^\pm)\BR(\psi(4S) \ra \eta J/\psi)<6.8\times 10^{-6}$ is obtained in $B^\pm \ra \eta J/\psi K^\pm$ decays. By assuming the partial width of $\psi(4S) \to e^+e^-$ being 0.63 keV, the branching fraction limit $\BR(\psi(4S) \ra \eta J/\psi) < 1.3\%$ is obtained at the 90\% confidence level in $e^+e^- \ra \eta J/\psi$, which is consistent with the theoretical prediction., Comment: 4 pages, 2 figures

In this paper, I review recent progress in the study of the $XYZ$ particles at Belle. I only focus on studies with charmonium and one or more light mesons in the final states. This covers the X(3872), X(3915), Y(4140), X(4350), and the charged Z states., Comment: 6 pages, 7 figures. Proceedings of the PhiPsi09, Oct. 13-16, 2009, Beijing, China

In measuring the $\psip$ radiative decays at BESII, contribution of the background is serious in most of the final states. To extract the number of signal events, a fit to the $\chi^2$ distribution of kinematic fit using signal and background components is proposed. Extensive Monte-Carlo simulations (MCS) are performed, and the results show that the shape of $\chi^2$ distribution of the signal channel looks different from those of the background channels, thus it provides us by fitting the $\chi^2$ distribution of the data to extract the number of signal events. An input-output test is performed using MCS, and the uncertainty of the fit method is found to be less than 2%., Comment: 3 pages, 2 figures