BES Results on J/psi decays and Charmonium Transitions

Abstract

Results are reported based on samples of 58 million $\jpsi$ and 14 million $\psip$ decays obtained by the BESII experiment. Improved branching fraction measurements are determined, including branching fractions for $\jpsi\to\ppp$, $\psip\ra π^0\J$, $η\J$, ${\pi }^0{\pi }^{0}J/\psi$, anything $J/\psi$, and $ψ(2S)\arγχ_{c1},γχ_{c2}\arγγ\jpsi$. The decay $J/\psi \to \omega {\pi }^{+}{\pi }^{-}$ is studied. At low $\pi \pi$ mass, a large, broad peak due to the $\sigma$ is observed, and its pole position is determined. Results are presented on $\psi (2S)$ and $J/\psi$ hadronic decays to $K_S^{0}p{K}^{-}\bar{n}$ and $K_S^0\bar{p}{K}^{+}n$ final states. No significant $\Theta (1540)$ signal, the pentaquark candidate, is observed, and upper limits are set. An enhancement near the $m_p+M_{\Lambda }$ mass threshold is observed in the $p\bar{\Lambda }$ invariant mass spectrum from $J/\psi \to p{K}^{-}\bar{\Lambda }+c.c.$ decays. It can be fit with an S-wave Breit-Wigner resonance with a mass $m=2075\pm 12(stat)\pm 5(syst)$ MeV and a width of $\Gamma =90\pm 35(stat)\pm 9(syst)$ MeV.

Proceedings contribution for Meson2004 Conference, 10 pages, 7 figures

References in corpus (7)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Evidence for Narrow S=+1 Baryon Resonance in Photo-production from Neutron
• Observation of a near-threshold enhancement in th p pbar mass spectrum from radiative J/psi-->gamma p pbar decays
• Observation of $B^{\pm }\to p\bar{p}{K}^{\pm }$
• A New State of Baryonium
• Observation of B0bar --> D(*)0 p pbar
• Observation of B0 to p Lambdabar pi-

Cited by in corpus (3)

• Analysis of $P_c^{+}(4380)$ and $P_c^{+}(4450)$ as pentaquark states in the molecular picture with QCD sum rules
• Strong Decay of $P_c(4380)$ Pentaquark in a Molecular Picture
• Extraction of scattering lengths from final-state interactions