Measurement of branching fraction ratios and CP asymmetries in B±→DCPK±

We report results on the decay B--->DCPK- and its charge conjugate using a data sample of 85.4x10(6) B (B) over bar pairs recorded at the Y(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes are determined to be B(B--->(DK-)-K-0)/B(B--->D(0)pi(-))=0.077+/-0.005(stat)+/-0.006(syst), B(B--->D1K-)/B(B--->D(1)pi(-))=0.093+/-0.018(stat)+/-0.008(syst) and B(B--->D2K-)/B(B--->D(2)pi(-))=0.108+/-0.019(stat)+/-0.007(syst) where the indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D-0-(D) over bar (0) system, respectively. We find the partial-rate charge asymmetries for B--->DCPK- to be A(1)=0.06+/-0.19(stat)+/-0.04(syst) and A(2)=-0.19+/-0.17(stat)+/-0.05(syst).