PT Journal
AU BABAR Collaboration (del Amo Sanchez, Pea
   Lopez-March, N
   Martinez-Vidal, F
   Milanes, DA
   Oyanguren, A
TI Observation of the Decay B- -> D_s(*) K- l- nu(bar)
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2011
BP 041804
EP 8pp
VL 107
IS 4
DI 10.1103/PhysRevLett.107.041804
LA English
AB We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb(-1) of data collected at the Y(4S) resonance with the BABAR detector at the PEP-II e(+)e(-) storage rings at SLAC. A simultaneous fit to three D(s)(+) decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B(-) -> D(s)(()*())K(-)l(-)(nu) over bar (l) = [6.13(-1.03)(+1.04)(stat) +/- 0.43(syst) +/- 0.51 (B(D(s)))] X 10(-4), where the last error reflects the limited knowledge of the D(s) branching fractions.
ER