Experiment	Measurement	Reference
CDF	\([0.257 \pm 0.020\mbox{ (stat)} \pm 0.014\mbox{ (syst)}] \times 10^{0}\)	PRD 84, 052012 (2011)
Average	\(\mathbf{[0.257 \pm 0.024\mbox{ (combined)}] \times 10^{0}}\)