A binned Dalitz plot analysis of B±→DK± decays, with D→KS0π+π- and D→KS0K+K-, is performed to measure the CP-violating observables x± and y± which are sensitive to the CKM angle γ. The analysis exploits 1.0 fb-1 of data collected by the LHCb experiment. The study makes no model-based assumption on the variation of the strong phase of the D decay amplitude over the Dalitz plot, but uses measurements of this quantity from CLEO-c as input. The values of the parameters are found to be x-=(0.0±4.3±1.5±0.6)×10-2, y-=(2.7±5.2±0.8±2.3)×10-2, x+=(-10.3±4.5±1.8±1.4)×10-2 and y+=(-0.9±3.7±0.8±3.0)×10-2. The first, second, and third uncertainties are the statistical, the experimental systematic, and the error associated with the precision of the strong-phase parameters measured at CLEO-c, respectively. These results correspond to γ=(44-38+43)°, with a second solution at γ→γ+180°, and rB=0.07±0.04, where rB is the ratio between the suppressed and favoured B decay amplitudes. © 2012 CERN.
- Nuclear and High Energy Physics