| Experiment | Measurement | Reference |
|---|---|---|
| Belle | \([1.27 \pm 0.11\mbox{ (stat)} \pm 0.11\mbox{ (syst)}] \times 10^{-4}\) | PTEP 2014 (2014) 043C01 |
| BaBar | \([1.08 \pm 0.23\mbox{ (stat)} \pm 0.24\mbox{ (syst)} \pm 0.03\mbox{ (psi/eta br (correlated))}] \times 10^{-4}\) | PRL 93 041801 (2004) |
| Average | \(\mathbf{[1.24 \pm 0.14\mbox{ (combined)}] \times 10^{-4}}\) |