2017/07/31 by LHCb collaboration, R. Aaij, B. Adeva +805 · 2 citations
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1103/physrevlett.119.112001
published as Phys. Rev. Lett. 119, 112001 (2017) · All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-018.html
arxiv created 2017/09/14 · arxiv updated 2017/09/20
A highly significant structure is observed in the Λc+K-π+π+ mass spectrum, where the Λc+ 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 Ξcc++. The difference between the masses of the Ξcc++ and Λc+ states is measured to be 1334.94 ± 0.72 (stat) ± 0.27 (syst~MeV/c2, and the Ξcc++ mass is then determined to be 3621.40 ± 0.72 (stat) ± 0.27 (syst ± 0.14 (Λc+)~MeV/c2, where the last uncertainty is due to the limited knowledge of the Λc+ 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.