| Experiment | Measurement | Reference |
|---|---|---|
| D0 | \([0.035 \pm 0.010\mbox{ (stat)} \pm 0.011\mbox{ (syst)}] \times 10^{0}\) | PRL 102, 091801 (2009) |
| CDF | \([3.38 \pm 0.25\mbox{ (stat)} \pm 0.30\mbox{ (syst)} \pm 0.56\mbox{ (norm)}] \times 10^{-2}\) | PRL 108, 201801 (2012) |
| Average | \(\mathbf{[3.40 \pm 0.62\mbox{ (combined)}] \times 10^{-2}}\) |