Experiment	Measurement	Reference
LHCb	\([4.2 \pm 1.8\mbox{ (stat)} \pm 0.7\mbox{ (syst)}] \times 10^{-2}\)	PRD 84 092001 (2011), Erratum: PRD 85 039904 (2012)
Average	\(\mathbf{[4.2 \pm 1.9\mbox{ (combined)}] \times 10^{-2}}\)