Using 58 million J/ψ decays, we have investigated the ppˉ invariant mass spectrum in the radiative decay J/ψ→γppˉ and observe a prominent structure with mass near 2mp. Fitting with an S-wave Breit-Wigner, we obtain a peak mass of M=1859−10+3(stat)−25+5(sys)MeV/c2. J/ψ→γηc decays from the same sample are used to determine the mass, width, and hadronic branching ratios of the ηc. From a sample of 14 million ψ(2S) events, the first observation of χcJ (J=0,1,2) decays to ΛΛˉ is made, and branching ratios are determined, which are larger than expected from the Color Octet Model. Branching ratios of Ks0KL0 in both ψ(2S) and J/ψ decays are measured, and a more than four sigma deviation from the pQCD predicted "12% rule" is observed. In ψ(3770) decays, evidence for the non-DDˉ decay to π+π−J/ψ is observed.
@article{arxiv.hep-ex/0310036,
title = {Recent BES charmonium results},
author = {Jiangchuan Chen and Frederick A. Harris},
journal= {arXiv preprint arXiv:hep-ex/0310036},
year = {2011}
}
Comments
Submitted to the proceedings of EPS2003. 5 pages, 10 figures