| Experiment | Measurement | Reference |
|---|---|---|
| Belle | < \(3.45 \times 10^{-6}\) | PRL 107, 091803 (2011) |
| BaBar | \([9.5 \pm 2.7\mbox{ (stat)} \pm 0.6\mbox{ (syst)}] \times 10^{-6}\) | PRL 102 132001 (2009) |
| Average | \(\mathbf{[9.5 \pm 2.8\mbox{ (combined)}] \times 10^{-6}}\) |