Measurement of the Decay B-s(0) -> D-s(-)pi(+) and Evidence for B-s(0) -> (DsK +/-)-K--/+ in e(+) e(-) Annihilation at root s approximate to 10.87 GeV

Abstract

We have studied B-s(0) -> D-s(-)pi(+) and B-s(0) -> (DsK +/-)-K--/+ decays using 23.6 fb(-1) of data collected at the Y(5S) resonance with the Belle detector at the KEKB e(+) e(-) collider. This highly pure B-s(0) -> D-s(-)pi(+) sample is used to measure the branching fraction, B(B-s(0) -> D-s(-)pi(+)) = [3.67(-0.33)(+0.35)(stat)(-0.42)(+0.43)(syst) +/- 0.49(f(s))] x 10(-3) (f(s) = N-Bs(*)(B) over bars(*)/N-b (b) over bar and the fractions of B-s(0) event types at the Y(d5S) energy, in particular N-Bs(*)(B) over bars(*)/N-Bs(*)(B) over bars(*) = (90.1(-4.0)(+3.8) +/- 0.2)%. We also determine the masses M(B-s(0)) = (5364.4 +/- 1.3 +/- 0.7) MeV/c(2) and M(B-s*) = (5416.4 +/- 0.4 +/- 0.5) MeV/c(2). In addition, we observe B-s(0) -> (DsK +/-)-K--/+ decays with a significance of 3.5 sigma and measure B(B-s(0) -> (DsK +/-)-K--/+) = [2.4-1.0+1.2(stat) +/- 0.3(syst) +/- 0.3(f(s))] x 10(-4).