A new upper limit is presented for the branching ratio (BR) of Î•â† 3Î. This decay is not allowed by charge-conjugation invariance. We have determined that BR(Î•â † 3Î)<4Ã 10-5. We also obtained BR(Î•â † Ï€0Î â† 3Î)<9Ã- 10-5; this decay mode is absolutely forbidden, as it violates conservation of angular momentum. Finally, we have established that BR(Î•â† Ï€0Ï€0Î Î)<1.2Ã 10-3 in a restricted diphoton-energy region. All three upper limits are at the 90% confidence level. They were obtained by using the Crystal Ball multiphoton spectrometer at the AGS and are based on the analysis of 28 million Î• mesons produced in the Ï€-pâ† Î•n reaction close to threshold.
ASJC Scopus subject areas
- Nuclear and High Energy Physics