We report the first observation of the decays B0→p¯ΛD(*)−. The data sample of 711 fb−1 used in this analysis corresponds to 772×106 B¯B pairs, collected at the Υ(4S) resonance by the Belle detector at the KEKB asymmetric-energy e+e− collider. We observe 19.8σ and 10.8σ excesses of events for the two decay modes and measure the branching fractions of B0→p¯ΛD− and B0→p¯ΛD*− to be (25.1±2.6±3.5)×10−6 and (33.6±6.3±4.4)×10−6, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon (p¯Λ) system is observed, consistent with that observed in similar B decays.
Physical Review Letters
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