First observations of B̅[0 over s]→D[superscript +]D[superscript -], D[+ over s]D[superscript -] and D[superscript 0]D̅[superscript 0] decays

Abstract

First observations and measurements of the branching fractions of the B̅[0 over s]→D[superscript +]D[superscript -], B̅[0 over s]→D[+ over s]D[superscript -] and B̅[0 over s]→D[superscript 0]D̅[superscript 0] decays are presented using 1.0 fb[superscript -1] of data collected by the LHCb experiment. These branching fractions are normalized to those of B̅[superscript 0]→D[superscript +]D[superscript -], B[superscript 0]→D[superscript -]D[+ over s] and B[superscript -]→D[superscript 0]D[- over s], respectively. An excess of events consistent with the decay B̅[superscript 0]→D[superscript 0]D̅[superscript 0] is also seen, and its branching fraction is measured relative to that of B[superscript -]→D[superscript 0]D[- over s]. Improved measurements of the branching fractions B(B̅[0 over s]→D[+ over s]D[- over s]) and B(B[superscript -]→D[superscript 0]D[- over s]) are reported, each relative to B(B[superscript 0]→D[superscript -]D[+ over s]). The ratios of branching fractions are B(B̅[0 over s]→D[superscript +]D[superscript -])/B(B̅[superscript 0]→D[superscript +]D[superscript -])=1.08±0.20±0.10, B(B̅[0 over s]→D[+ over s]D[superscript -])/B(B[superscript 0]→D[superscript -]D[+ over s])=0.050±0.008±0.004, B(B̅[0 over s]→D[superscript 0]D̅[superscript 0])/B(B[superscript -]→D[superscript 0]D[- over s])=0.019±0.003±0.003, B(B̅[superscript 0]→D[superscript 0]D̅[superscript 0])/B(B[superscript -]→D[superscript 0]D[- over s])<0.0024 at 90% CL, B(B̅[0 over s]→D[+ over s]D[- over s])/B(B[superscript 0]→D[superscript -]D[+ over s])=0.56±0.03±0.04, B(B[superscript -]→D[superscript 0]D[- over s])/B(B[superscript 0]→D[superscript -]D[+ over s])=1.22±0.02±0.07, where the uncertainties are statistical and systematic, respectively.