Abstrakt
We present an analysis of the semi-inclusive decays B-s -> D(s)(-)Xl(+)nu and B-s -> D-s*(-)Xl(+)nu, where X denotes a final state that may consist of additional hadrons or photons and l is an electron or muon. The studied Bs decays are contained in the 121.4 fb(-1) Upsilon(5S) data sample collected by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.
The branching fractions of the decays are measured to be B(B-s -> D(s)(-)Xl(+)nu) = [8.2 +/- 0.2(stat) +/- 0.6(syst) +/- 1.4(ext)] % and B(B-s -> D-s*(-)Xl(+)nu) = [5.4 +/- 0.4(stat) +/- 0.4(syst) +/- 0.9(ext)] %, where the first two uncertainties are statistical and systematic and the last is due to external parameters. The measurement also provides an estimate of the B-s(()*())(B) over bar (()(s)*()) production cross section, sigma(e(+)e(-) -> B-s(()*())(B) over bar (()(s)*())) = 53.8 +/- 1.4(stat) +/- 4.0(syst) +/- 3.4(ext)] pb, at the center-of-mass energy root s = 10.86 GeV.