| Experiment | Measurement | Reference |
|---|---|---|
| Belle | \([2.29 \pm 0.39\mbox{ (stat)} \pm 0.40\mbox{ (syst)}] \times 10^{-4}\) | PRD 74, 092002 (2006) |
| BaBar | \([4.55 \pm 0.24\mbox{ (stat)} \pm 0.39\mbox{ (syst)}] \times 10^{-4}\) | PRD 84, 112007 (2011) |
| Average | \(\mathbf{[3.64 \pm 0.35\mbox{ (combined)}] \times 10^{-4}}\) |