Experiment	Measurement	Reference
Belle	\([6.1 \pm 0.6\mbox{ (stat)} \pm 0.9\mbox{ (syst)} \pm 1.6\mbox{ (model)}] \times 10^{-4}\)	PRD 69, 112002(2004)
BaBar	\([6.8 \pm 0.3\mbox{ (stat)} \pm 0.4\mbox{ (syst)} \pm 2.0\mbox{ (model)}] \times 10^{-4}\)	PRD 79, 112004 (2009)
Average	\(\mathbf{[6.3 \pm 1.9\mbox{ (combined)}] \times 10^{-4}}\)