Abstract
We present evidence for the exclusive reaction , observed with the Mark III detector at the SLAC storage ring SPEAR. The is reconstructed in the decay mode, while the is detected as a narrow peak in the recoil-mass distribution. The mass of the is found to be 2109.3±2.1±3.1 MeV/, yielding a mass difference of 137.9±2.1±4.3 MeV/. The width of the is <22 MeV/ at the 90%-confidence level. The observed signal corresponds to pb at GeV.
- Received 24 February 1987
DOI:https://doi.org/10.1103/PhysRevLett.58.2171
©1987 American Physical Society