Abstract
We observe a narrow enhancement near in the invariant mass spectrum of pairs from radiative decays. No similar structure is seen in decays. The results are based on an analysis of a event sample of decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an - or -wave Breit-Wigner resonance function. In the case of the -wave fit, the peak mass is below at and the total width is at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.
- Received 7 March 2003
DOI:https://doi.org/10.1103/PhysRevLett.91.022001
©2003 American Physical Society