Observation of tree-level B decays with ss̄ production from gluon radiation

We report on our search for decays proceeding via a tree-level b{yields}c quark transition in which a gluon radiates into an ss pair. We present observations of the decays B{sup -}{yields}D{sub s}{sup (*)+}K{sup -}{pi}{sup -} and B{sup 0}{yields}D{sub s}{sup +}K{sub S}{sup 0}{pi}{sup -} and evidence for B{sup -}{yields}D{sub s}{sup +}K{sup -}K{sup -} and set upper limits on the branching fractions for B{sup 0}{yields}D{sub s}*{sup +}K{sub S}{sup 0}{pi}{sup -} and B{sup -}{yields}D{sub s}*{sup +}K{sup -}K{sup -} using 383x10{sup 6} {upsilon}(4S){yields}BB events collected by the BABAR detector at SLAC. We present evidence that the invariant mass distributions of D{sub s}{sup (*)+}K{sup -} pairs from B{sup -}{yields}D{sub s}{sup (*)+}K{sup -}{pi}{sup -} decays are inconsistent with the phase-space model, suggesting the presence of charm resonances lying below the D{sub s}{sup (*)+}K{sup -} threshold.