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LHCb - Abteilung Hinton
Abstract:
The decays Λb0 → Λc+ D(∗)0 K− and Λb0 → Λc+ Ds∗− are observed for the first time, in proton-proton collision data at √s = 13TeV, corresponding to an integrated luminosity of 5.4fb−1 collected with the LHCb detector. Their ratios of branching fractions with respect to the Λb0 → Λc+ Ds− mode are measured to be
B (Λb0 → Λc+ D0 K−) / B (Λb0 → Λc+ Ds− ) = 0.1908 −0.0034−0.0018+0.0036+0.0016 ± 0.0038,
B (Λb0 → Λc+ D∗0 K−) / B (Λb0 → Λc+ Ds−) = 0.589−0.017−0.018+0.018+0.017 ± 0.012,
B (Λb0 → Λc+ Ds∗− ) / B (Λb0 → Λc+ Ds− ) = 1.668 ± 0.022−0.055+0.061,
where the first uncertainties are statistical, the second sys- tematic, and the third, for the Λb0 → Λc+ D(∗)0 K− decays, are due to the uncertainties on the branching fractions of the Ds− → 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 Λb0 → Λc+ D(∗)0 K− decay channels.