| Experiment | Measurement | Reference |
|---|---|---|
| BaBar | < \(28.6 \times 10^{-4}\) | PRL 94 171801 (2005) |
| BaBar | \([1.4 \pm 0.5\mbox{ (stat)} \pm 0.2\mbox{ (syst)}] \times 10^{-4}\) | PRD(RC) 78 091101 (2008) |
| Average | \(\mathbf{[1.4 \pm 0.5\mbox{ (combined)}] \times 10^{-4}}\) |