Measurement of CP-Asymmetries for the Decays B+/- to D_cp Kstar+/- with the BABAR Detector

Abstract

Using a sample of 227 million Υ(4S)→BB¯ events collected with the BABAR detector at the PEP-II B Factory in 1999--2004, we study B−→D0K∗(892)− decays where K∗−→K0Sπ− and D0→K−π+,K−π+π0,K−π+π+π− (non-CP final states), K+K−,π+π−(CP+ eigenstates), K0S π0,K0Sϕ and K0Sω(CP− eigenstates). The partial rate charge asymmetries ACP and the ratios RCP defined in the literature as the sum of the B+ and B− partial rates to a charged K∗ and a D0CP-eigenstate divi ded by the B→D0K∗ decay rate, %of the \ensuremath{\Bu}\xspace\xspace m \ensuremath{\to}\xspace \Dcp \ensuremath{K^*}\xspacepm branch ing fractions summed over %\B charge to the \ensuremath{B^-}\xspace \xspace\ensuremath{\to}\xspace \ensuremath{D^0}\xspace \ensu remath{K^{*-}}\xspace branching fraction are sensitive to the angle γ of the CKM unitarity triangle. We measure: \mathcal{A}_{CP+} &=&-0.09 \pm 0.20 (stat.) \pm 0.06 (syst.) \mathcal{A}_{CP-} &=& -0.33 \pm 0.34 (stat.) \pm 0.10 (syst.) (+1.15 \pm 0.12) \cdot (\mathcal{A}_{CP-} - \mathcal{A}_{CP+}) \mathcal{R}_{CP+} &=& +1.77 \pm 0.37 (stat.) \pm 0.12 (syst.) \mathcal{R}_{CP-} &=& +0.76 \pm 0.29 (stat.) \pm 0.06 (syst.) ^{- 0.04}_{-\ 0.14} The third uncertainty quoted for the CP- measurements reflects possible interference effects in the final states with ϕ and ω resonances. All results are preliminary.