A Model-Independent Dalitz Plot Analysis of B[superscript ±]→DK[superscript ±] with D→K[superscript 0][subscript S]h[superscript +]h[superscript −] (H=π,K) Decays and Constraints on the CKM Angle γ

Abstract

A binned Dalitz plot analysis of B[superscript ±]→DK[superscript ±] decays, with D→K[superscript 0][subscript S]π[superscript +]π[superscript -] and D→K[superscript 0][subscript S]K[superscript +]K[superscript -], is performed to measure the CP-violating observables x[subscript ±] and y[subscript ±] which are sensitive to the CKM angle γ. The analysis exploits 1.0 fb[superscript -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[subscript -] =(0.0±4.3±1.5±0.6)×10 -2, y[subscript ]- =(2.7±5.2±0.8±2.3)×10 -2, x[subscript +] =(-10.3±4.5±1.8±1.4)×10 -2 and y[subscript +] =(-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[subscript -38][superscript +43])°, with a second solution at γ→γ+180°, and r B =0.07±0.04, where r B is the ratio between the suppressed and favoured B decay amplitudes. © 2012 CERN.