| Experiment | Measurement | Reference |
|---|---|---|
| Belle | \([2.31 \pm 0.11\mbox{ (stat)} \pm 0.14\mbox{ (syst)}] \times 10^{-3}\) | Phys. Rev. D 92, 012013 (2015) |
| BaBar | \([2.88 \pm 0.21\mbox{ (stat)} \pm 0.28\mbox{ (syst)} \pm 0.14\mbox{ (correlated syst)}] \times 10^{-3}\) | PRD 74 (2006) 012001 |
| Average | \(\mathbf{[2.41 \pm 0.16\mbox{ (combined)}] \times 10^{-3}}\) |