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Free keywords:
B Physics, Branching fraction, Flavour Physics, Hadron-Hadron Scattering
MPINP:
LHCb - Abteilung Hinton
Abstract:
The Λb0 → D+D−Λ decay is observed for the first time using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.3 fb−1. Using the B0 → D+D−KS0 decay as a reference channel, the product of the relative production cross-section and decay branching fractions is measured to be
R = (σΛb0 / σB0) × (B(Λb0 → D+D−Λ)) / (B(B0 → D+D−KS0)) = 0.179 ± 0.022 ± 0.01,
where the first uncertainty is statistical and the second is systematic. The known branching fraction of the reference channel, B(B0 → D+D−KS0), and the cross-section ratio, σΛb0 / σB0 , previously measured by LHCb are used to derive the branching fraction of the Λb0 → D+D−Λ decay
B(Λb0 → D+D−Λ) = (1.24 ± 0.15 ± 0.10 ± 0.28 ± 0.11) × 10−4,
where the third and fourth contributions are due to uncertainties of B(B0 → D+D−KS0) and σΛb0 / σB0, respectively. Inspection of the D+Λ and D+D− invariant-mass distributions suggests a rich presence of intermediate resonances in the decay. The Λb0 → D∗+D−Λ decay is also observed for the first time as a partially reconstructed component in the D+D−Λ invariant mass spectrum.