Experiment	Measurement	Reference
Belle	\([5.5 \pm 1.4\mbox{ (stat)} \pm 0.8\mbox{ (syst)}] \times 10^{-4}\)	PLB 542, 171 (2002)
Average	\(\mathbf{[5.5 \pm 1.6\mbox{ (combined)}] \times 10^{-4}}\)