Observation of Λ0b → Λ+c D(∗)0K− and Λ0b → Λ+c D∗−s decays

The decays Λ0b → Λ+c D(∗)0K− and Λ0b → Λ+c D∗−s are observed for the first time, in proton-proton collision data at √s = 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1 collected with the LHCb detector. Their ratios of branching fractions with respect to the Λ0b → Λ+c D−s mode are measured to be: B(Λ0b → Λ+c D0K−) / B(Λ0b → Λ+c D−s) = 0.1908+0.0036−0.0034 +0.0016−0.0018 ± 0.0038, B(Λ0b → Λ+c D∗0K−) / B(Λ0b → Λ+c D−s) = 0.589+0.018−0.017 +0.017−0.018 ± 0.012, B(Λ0b → Λ+c D∗−s) / B(Λ0b → Λ+c D−s) = 1.668 ± 0.022+0.061−0.055, where the first uncertainties are statistical, the second systematic, and the third, for the Λ0b → Λ+c D(∗)0K− decays,are due to the uncertainties on the branching fractions of the D−s → K−K+π− and D0 → K+π− decay modes. The measured branching fractions probe factorization assumptions in effective theories and provide the normalization for future pentaquark searches in Λ0b → Λ+c D(∗)0K− decay channels.