Abstract
We report the first evidence for the decay from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is . The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, with a mass of and branching ratio .
- Received 3 November 2004
DOI:https://doi.org/10.1103/PhysRevLett.94.021801
©2005 American Physical Society