Observation of Tree-Level B Decays with s¯s Production from Gluon Radiation

Abstract

We report on our search for decays proceeding via a tree-level b → c quark transition in which a gluon radiates into an s ¯ s pair. We present observations of the decays B − → D ( * ) + s K − π − and ¯¯¯ B 0 → D + s K 0 S π − and evidence for B − → D + s K − K − and set upper limits on the branching fractions for ¯¯¯ B 0 → D * + s K 0 S π − and B − → D * + s K − K − using 383 × 10 6 Υ ( 4 S ) → B ¯¯¯ B events collected by the BABAR detector at SLAC. We present evidence that the invariant mass distributions of D ( * ) + s K − pairs from B − → D ( * ) + s K − π − decays are inconsistent with the phase-space model, suggesting the presence of charm resonances lying below the D ( * ) + s K − threshold.