Observation of the Doubly Charmed Baryon Ξ++cc

P.E.L. Clarke, G.A. Cowan, S. Eisenhardt, F. Muheim, M. Needham, S. Playfer, LHCb Collaboration

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

A highly significant structure is observed in the Λ+cK−π+π+ mass spectrum, where the Λ+c baryon is reconstructed in the decay mode pK−π+. The structure is consistent with originating from a weakly decaying particle, identified as the doubly charmed baryon Ξ++cc. The difference between the masses of the Ξ++cc and Λ+c states is measured to be 1334.94±0.72(stat.)±0.27(syst.)  MeV/c2, and the Ξ++cc mass is then determined to be 3621.40±0.72(stat.)±0.27(syst.)±0.14(Λ+c)  MeV/c2, where the last uncertainty is due to the limited knowledge of the Λ+c mass. The state is observed in a sample of proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7  fb−1, and confirmed in an additional sample of data collected at 8 TeV.
Original languageEnglish
Article number112001
JournalPhysical Review Letters
Issue number11
Publication statusPublished - 11 Sept 2017


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