Abstract
The branching ratio of the rare decay has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. We observed 275 candidate events, with an expected background of events which includes the contribution from Dalitz decays. We measured , where the first error is statistical and the second systematic. This result is the first significant observation of the excess rate for this decay above the unitarity lower bound.
- Received 10 March 1999
DOI:https://doi.org/10.1103/PhysRevLett.83.922
©1999 American Physical Society