Abstract
We report the results of a search for the leptonic decay → using the Mark III detector at the SLAC storage ring SPEAR. A data sample of 9.3 collected at the ψ(3770) resonance yields no signal events, corresponding to a 90%-confidence-level upper limit of 7.2× on the branching ratio B(→). This represents an upper limit on the pseudoscalar decay constant of 290 MeV/.
- Received 13 October 1987
DOI:https://doi.org/10.1103/PhysRevLett.60.1375
©1988 American Physical Society