Dalitz plot analyses of B 0 → D − D 0 K þ and B þ → ¯ D 0 D 0 K þ decays

We present Dalitz plot analyses for the decays of B mesons to D − D 0 K þ and ¯ D 0 D 0 K þ . We report the observation of the D (cid:2) s 1 ð 2700 Þ þ resonance in these two channels and obtain measurements of the mass M ð D (cid:2) s 1 ð 2700 Þ þ Þ ¼ 2699 þ 14 − 7 MeV =c 2 and of the width Γ ð D (cid:2) s 1 ð 2700 Þ þ Þ ¼ 127 þ 24 − 19 MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D 0 K þ invariant mass around 2350 – 2500 MeV =c 2 in both decays B 0 → D − D 0 K þ and B þ → ¯ D 0 D 0 K þ , which we are not able to interpret. The results are based on 429 fb − 1 of data containing 471 × 10 6 B ¯ B pairs collected at the ϒ ð 4 S Þ resonance with the BABAR detector at the SLAC National Accelerator Laboratory.