| Experiment | Measurement | Reference |
|---|---|---|
| CDF | \([1.92 \pm 0.60\mbox{ (stat)} \pm 0.17\mbox{ (syst)}] \times 10^{0}\) | PRD 54 6596 (1996) |
| BaBar | \([1.37 \pm 0.05\mbox{ (stat)} \pm 0.08\mbox{ (syst)}]\) | PRL 94 141801 (2005) |
| Average | \(\mathbf{[1.38 \pm 0.09\mbox{ (combined)}] \times 10^{0}}\) |