Experiment
Measurement
Reference
Belle
< \(3.0 \times 10^{-6}\)
Belle:cref:0727 (superseded)
Belle
< \(3.6 \times 10^{-6}\)
PRL 101, 041601 (2008)
Average
< \(\mathbf{3.6 \times 10^{-6}}\)