Determination of fs/fd for 7 TeV pp Collisions and Measurement of the B0 → D-K+ Branching Fraction

The relative abundance of the three decay modes B-0 -> D-K+, B-0 -> D-pi(+), and B-s(0) -> D-s(-)pi(+) produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb(-1). The branching fraction of B-0 -> D-K+ is found to be B(B-0 -> D-K+) = (2.01 +/- 0.18(stat) +/- 0.14(syst)) x 10(-4). The ratio of fragmentation fractions f(s)/f(d) is determined through the relative abundance of B-s(0) -> D-s(-)pi(+) to B-0 -> D-K+ and B-0 -> D-pi(+), leading to f(s)/f(d) = 0.253 +/- 0.017 +/- 0.017 +/- 0.020, where the uncertainties are statistical, systematic, and theoretical, respectively.