First observation and branching fraction measurement of the Λb0→Ds−pΛb0​→Ds−​p decay

The first observation of the Λb0→Ds−pΛb0​→Ds−​p decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of ss ​ = 13 TeV, corresponding to a total integrated luminosity of 6 fb−1−1. Using the Λb0→Λc+π−Λb0​→Λc+​π− decay as the normalisation mode, the branching fraction of the Λb0→Ds−pΛb0​→Ds−​p decay is measured to be B(Λb0→Ds−p)=(12.6±0.5±0.3±1.2)×10−6B(Λb0​→Ds−​p)=(12.6±0.5±0.3±1.2)×10−6, where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the Λb0→Λc+π−Λb0​→Λc+​π−, Ds−→K−K+π−Ds−​→K−K+π− and Λc+→pK−π+Λc+​→pK−π+ decays.[graphic not available: see fulltext]