Preliminary Result of Frascati (ADONE) on the Nature of a New 3.1-GeV Particle Produced in e+ e- Annihilation

fications system is not functioning and we therefore cannot separate muons from strongly interacting particles. However, outside the peak the data are consistent with our previously measured p. -pair cross section. Since a large wg or EE branching ratio would be unexpected for a resonance this massive, the two-body enhancement observed is probably but not conclusively in the p, -pair channel. The e'e hadron cross section is presumed to go through the one-photon intermediate state with angular momentum, parity, and charge conjugation quantum numbers J~c = 1 . . It is difficult to understand how, without involving new quantum numbers or. selection rules, a resonance in this state which decays to hadrons could be so nal row. We wish to thank the SPEAR operations staff for providing the stable conditions of machine performance necessary for this experiment. Special monitoring and control techniques were developed on very short notice and performed excellently.