Experiment	Measurement	Reference
LHCb	\([4.0 \pm 1.0\mbox{ (stat)} \pm 0.4\mbox{ (syst)}] \times 10^{-3}\)	PRD 86, 112005 (2012)
Average	\(\mathbf{[4.0 \pm 1.1\mbox{ (combined)}] \times 10^{-3}}\)