Measurement of the CKM angle γ using B[superscript ±] → DK[superscript ±] with D → K[0 over S] π[superscript +] π[superscript −], K[0 over S] K[superscript +] K[superscript −] decays

Abstract

A binned Dalitz plot analysis of B[superscript ±] → DK[superscript ±] decays, with D → K[0 over S] π[superscript +] π[superscript −] and K[0 over S] K[superscript +] K[superscript −], is performed to measure the CP-violating observables x[subscript ±] and y[subscript ±], which are sensitive to the Cabibbo-Kobayashi-Maskawa angle γ. The analysis exploits a sample of proton-proton collision data corresponding to 3.0 fb[superscript −1] collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phase of the D decay over the Dalitz plot are used as inputs. The values of the parameters are found to be x[subscript +] = (−7.7 ± 2.4 ± 1.0 ± 0.4) × 10[superscript − 2], x[subscript −] = (2.5 ± 2.5 ± 1.0 ± 0.5) × 10[superscript − 2], y[subscript +] = (−2.2 ± 2.5 ± 0.4 ± 1.0) × 10[superscript − 2] and y[subscript −] = (7.5 ± 2.9 ± 0.5 ± 1.4) × 10[superscript − 2]. The first, second, and third uncertainties are the statistical, the experimental systematic, and that associated with the precision of the strong-phase parameters. These are the most precise measurements of these observables and correspond to γ = (62[+15 over -14])° , with a second solution at γ → γ + 180°, and r[subscript B] = 0.080 [+0.019 over -0.021], where r[subscript B] is the ratio between the suppressed and favoured B decay amplitudes.