| Experiment | Measurement | Reference |
|---|---|---|
| Belle | < \(0.33 \times 10^{-4}\) | PRD(RC) 75, 011101 (2007) |
| BaBar | \([2.2 \pm 0.7\mbox{ (stat)} \pm 0.1\mbox{ (syst)} \pm 0.6\mbox{ (Lambdac+ BF)}] \times 10^{-5}\) | PRD 87, 092004 (2013) |
| Average | \(\mathbf{[2.2 \pm 0.9\mbox{ (combined)}] \times 10^{-5}}\) |