@article{b7b294eefc984ef5a9b11269ed98e6f6,
title = "Observation of the Doubly Charmed Baryon Ξcc + +",
abstract = "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.",
author = "{(LHCb Collaboration)} and R. Aaij and B. Adeva and M. Adinolfi and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and S. Ali and G. Alkhazov and {Alvarez Cartelle}, P. and Alves, {A. A.} and S. Amato and S. Amerio and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and Andrews, {J. E.} and Appleby, {R. B.} and F. Archilli and P. D'Argent and {Arnau Romeu}, J. and A. Artamonov and M. Artuso and E. Aslanides and G. Auriemma and M. Baalouch and I. Babuschkin and S. Bachmann and Back, {J. J.} and A. Badalov and C. Baesso and S. Baker and V. Balagura and W. Baldini and A. Baranov and Barlow, {R. J.} and C. Barschel and S. Barsuk and W. Barter and F. Baryshnikov and V. Batozskaya and V. Battista and A. Bay and L. Beaucourt and {Calvo Gomez}, M. and X. Vilasis-Cardona",
note = "Funding Information: We thank Chao-Hsi Chang, Cai-Dian L{\"u}, Xing-Gang Wu, and Fu-Sheng Yu for frequent and interesting discussions on the production and decays of double-heavy-flavor baryons. We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ, and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG, and MPG (Germany); INFN (Italy); NWO (The Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MinES and FASO (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted to the communities behind the multiple open source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany), EPLANET, Marie Sk{\l}odowska-Curie Actions, and ERC (European Union), Conseil G{\'e}n{\'e}ral de Haute-Savoie, Labex ENIGMASS, and OCEVU, R{\'e}gion Auvergne (France), RFBR and Yandex LLC (Russia), GVA, XuntaGal, and GENCAT (Spain), Herchel Smith Fund, The Royal Society, Royal Commission for the Exhibition of 1851, and the Leverhulme Trust (United Kingdom). Publisher Copyright: {\textcopyright} 2017 CERN, for the LHCb Collaboration.",
year = "2017",
month = sep,
day = "11",
doi = "10.1103/PhysRevLett.119.112001",
language = "English",
volume = "119",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "11",
}