Measurement of CP violation and constraints on the CKM angle γ in B±→DK±B±→DK± with D→KS0π+π− decays

A model-dependent amplitude analysis of B±→DK±B±→DK± with D→KS0π+π− decays is performed using proton–proton collision data, corresponding to an integrated luminosity of 1 fb−11 fb−1, recorded by LHCb at a centre-of-mass energy of 7 TeV in 2011. Values of the CP   violation observables x±x± and y±y±, which are sensitive to the CKM angle γ, are measured to bex−=+0.027±0.044−0.008+0.010±0.001,y−=+0.013±0.048−0.007+0.009±0.003,x+=−0.084±0.045±0.009±0.005,x+=−0.084±0.045±0.009±0.005,y+=−0.032±0.048−0.009+0.010±0.008, where the first uncertainty is statistical, the second systematic and the third arises from the uncertainty of the D→KS0π+π− amplitude model. The value of γ   is determined to be (84−42+49)°, including all sources of uncertainty. Neutral D meson mixing is found to have negligible effect.