Observation of a Near-Threshold Enhancement in the p-anti-p Mass Spectrum from Radiative J/psi -> gamma-p-anti-p Decays.

Bai, J. Z. ; Ban, Y. ; Bian, J. G. ; Cai, X. ; Chang, J. F. ; Chen, H. F.

Technical Information Center Oak Ridge Tennessee

关键词: Electron-positron collider;    Radative decay;    Mass spectra;    Protons;    Antiprotons;   

RP-ID  :  DE2003813004

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We observe a narrow enhancement near 2m(sub p) in the invariant mass spectrum of p(bar p) pairs from radiative J/(psi)(yields)(gamma)p(bar p) decays. No similar structure is seen in J/(psi)(yields)(pi)(sup 0) p(bar p) decays. The results are based on an analysis of a 58 million event sample of J/(psi) decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit Wigner resonance function.