Zou, BS (reprint author), CCAST, World Lab, POB 8730, Beijing 100080, Peoples R China.
Article; Proceedings Paper
J/psi decay at Beijing Electron-Positron Collider (BEPC) is well known as the best place for looking for glueballs. But in fact it is also an excellent place for studying N* and hyperon physics. For J/psi --> N (N) over bar pi and N (N) over bar pi pi, the pi N and pi pi N systems are limited to be pure isospin 1/2 due to isospin conservation. This is a big advantage in studying N* resonances from J/psi decays, compared with the pi N and gamma N experiments which suffer difficulty on the isospin decomposition of 1/2 and 3/2. There are also plenty other decay modes of J/11, involving baryon-antibaryon pairs plus mesons which can be used to study N* and hyperon resonances, e.g., looking for the "missing" N* states from J/psi -->(p) over bar p omega, (p) over bar p eta', pK-(A) over bar, etc.; studying N*(1535) --> eta p from J/psi --> (p) over bar p eta and Studying Lambda(1405) --> Sigma pi from J/psi --> Lambda<(Sigma)over bar>-pi(+). It provides a new way to study the internal structure of baryon resonances. The newest progress and outlook in this field are presented.