Abstract
Using a data set with an integrated luminosity of collected at with the BESIII detector operating at the BEPCII storage rings, we search for the rare decay . No signal events are observed. We set the upper limit on the branching fraction for to be at the 90% confidence level.
- Received 22 August 2017
DOI:https://doi.org/10.1103/PhysRevD.96.092002
Published by the American Physical Society