First observations of B¯s0→D+D-, Ds+D- and D0D¯0 decays

Abstract

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