Study of N* production from J/ψ → p(p)over-barη

Data are presented on the reaction J/psi --> <p(p)over bar <eta>> using 7.8 x 10(6) J/psi triggers collected by the BEjing Spectrometer (BES). A partial wave analysis is performed. A clear enhancement near the p eta((p) over bar eta) threshold is observed. It is fitted with a J(P) = 1/2(-) resonance with mass M = 1530 +/- 10 MeV and width Gamma = 95 +/- 25 MeV. In addition, there is a peak around 1650 MeV with J(P) = 1/2(-) preferred also, fitted with M = 1637 +/- 20 MeV and Gamma = 145(-45)(+80) MeV. These two N* resonances are believed to be the two well established states, S-11(1535) and S-11(1650). respectively. It is the first partial wave study of the production of these resonances from J/psi decays. (C) 2001 Published by Elsevier Science B.V.