Experiment	Measurement	Reference
Belle	\([2.56 \pm 0.26\mbox{ (stat)} \pm 0.33\mbox{ (syst)}] \times 10^{-3}\)	PRD (R)70,111103(2004)
Average	\(\mathbf{[2.56 \pm 0.42\mbox{ (combined)}] \times 10^{-3}}\)