7 pages, 4 figuresWe report the observation of the decay $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}$ based on $342 \mathrm {\,fb}^{-1}}$ of data collected at the $\Y4S$ 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 $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}$ with a significance greater than five standard deviations (including systematic uncertainties) and measure its branching fraction to be $\BR(B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^{-} \bar{\nu}_{\ell}) = [6.13^{+1.04}_{-1.03}...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...
We report the observation of the decay B[superscript -]→D[subscript s][superscript (*)+]K[superscrip...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...
7 pages, 4 figuresWe report the observation of the decay $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^...
We report the observation of the decay B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{ell}{sup -}{bar...
We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb...
We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb...
We report the observation of the decay B- -> D-s(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb(-1...
We report the observation of the decay B- → D(s)((*)+) K- ℓ- ν(ℓ) based on 342 fb(-1) of data colle...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...
We report the observation of the decay B[superscript -]→D[subscript s][superscript (*)+]K[superscrip...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...
7 pages, 4 figuresWe report the observation of the decay $B^{-} \rightarrow D^{(*)+}_{s} K^{-} \ell^...
We report the observation of the decay B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{ell}{sup -}{bar...
We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb...
We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb...
We report the observation of the decay B- -> D-s(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb(-1...
We report the observation of the decay B- → D(s)((*)+) K- ℓ- ν(ℓ) based on 342 fb(-1) of data colle...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...
We report the observation of the decay B[superscript -]→D[subscript s][superscript (*)+]K[superscrip...
We report the observation of the decay B- D(s)((*)+) K- ℓ- nu(ℓ) based on 342fb(-1) of data collecte...