Abstract
Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare () decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed decays to the number of observed () decays. We find the value of , where the first uncertainty is statistical, the second systematic, and the third is the branching ratio uncertainty. Our result agrees well with the standard model prediction.
- Received 17 December 2003
DOI:https://doi.org/10.1103/PhysRevLett.93.181803
©2004 American Physical Society