Measurement of CP violation and constraints on the CKM angle γ in B±→DK± with D→K0Sπ+π−decays

Abstract

A model-dependent amplitude analysis of B±→DK±with D→K0Sπ+π−decays is performed using proton–proton collision data, corresponding to an integrated luminosity of 1fb−1, recorded by LHCb at a centre-of-mass energy of 7TeV in 2011. Values of the CPviolation observables x±and y±, which are sensitive to the CKM angle γ, are measured to be x− =+0.027±0.044+0.010 −0.008 ± 0.001, y− =+0.013±0.048+0.009 −0.007 ± 0.003, x+ =−0.084±0.045 ±0.009±0.005, y+ =−0.032±0.048+0.010 −0.009 ± 0.008, where the first uncertainty is statistical, the second systematic and the third arises from the uncertainty of the D→K0Sπ+π−amplitude model. The value of γis determined to be (84+49−42)◦, including all sources of uncertainty. Neutral Dmeson mixing is found to have negligible effect.