Abstract: A binned Dalitz plot analysis ofB±DK±decays, withDK0S+andDK0SK+K, is performed to measure the CP-violating observables x± and y±, which are sensitive to the Cabibbo-Kobayashi-Maskawa angle. The analysis exploits asample of proton-proton collision data corresponding to 3.0 fb1collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phaseof the D decay over the Dalitz plot are used as inputs. The values of the parameters arefound to be x+= (7.7±2.4±1.0±0.4)×102,x= (2.5±2.5±1.0±0.5)×102,y+= (2.2±2.5±0.4±1.0)×102, andy= (7.5±2.9±0.5±1.4)×102. The first,second, and third uncertainties are the statistical, the experimental systematic, and thatassociated with the precision of the strong-phase parameters. These are the most precisemeasurements of these observables and correspond to= (62+1514), with a second solution at + 180, and rB= 0.080+0.0190.021, wherer B is the ratio between the suppressed and favoured B decay amplitudes.
