Recent BES charmonium results

Abstract

Using 58 million $J/\psi$ decays, we have investigated the $p\bar{p}$ invariant mass spectrum in the radiative decay $J/\psi \to \gamma p\bar{p}$ and observe a prominent structure with mass near $2m_p$. Fitting with an S-wave Breit-Wigner, we obtain a peak mass of $M=1859_{-10}^{+3}(\mathrm{stat}{)}_{-25}^{+5}(\mathrm{sys})MeV/{\mathrm{c}}^2$. $J/\psi \to \gamma {\eta }_c$ decays from the same sample are used to determine the mass, width, and hadronic branching ratios of the ${\eta }_c$. From a sample of 14 million $\psi (2S)$ events, the first observation of ${\chi }_{cJ}$ (J=0,1,2) decays to $\Lambda \bar{\Lambda }$ is made, and branching ratios are determined, which are larger than expected from the Color Octet Model. Branching ratios of $K_s^0{K}_L^0$ in both $\psi (2S)$ and $J/\psi$ decays are measured, and a more than four sigma deviation from the pQCD predicted "12% rule" is observed. In $\psi (3770)$ decays, evidence for the non-$D\bar{D}$ decay to ${\pi }^{+}{\pi }^{-}J/\psi$ is observed.

Submitted to the proceedings of EPS2003. 5 pages, 10 figures

Cited by in corpus (3)

• Possible large phase in psi(2S) -> 1-0- Decays
• The Form Factors of omega pi0 and pi+ pi- at psi(2S)
• Direct search limits on the Littlest Higgs model