Abstract
In an experiment designed to search for and study very rare two-body decay modes of the , we have observed four examples of the decay , where the expected background is events. This observation translates into a branching fraction of , consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.
- Received 1 September 1998
DOI:https://doi.org/10.1103/PhysRevLett.81.4309
©1998 American Physical Society