Observation of the Doubly Charmed Baryon Ξ c c + with the LHCb Run 3 Detector

@article{aaij2026observation,
  title = {{Observation of the Doubly Charmed Baryon Ξ c c + with the LHCb Run 3 Detector}},
  author = {R. Aaij and M. Abdelfatah and A. S. W. Abdelmotteleb and Carlos Abellán Beteta and C. Abellán Beteta and T. Ackernley and A. A. Adefisoye and B. Adeva and M. Adinolfi and P. Adlarson and C. Agapopoulou and C. Aidala and S. Akar and K. Carvalho Akiba and P. Albicocco and J. Albrecht and R. Aleksiejūnas and F. Alessio and P. Álvarez Cartelle and S. Amato and J. L. Amey and Y. Amhis and L. An and L. Anderlini and M. Andersson and P. Andreola and M. Andreotti and Sergio Andres Estrada and Alessia Anelli and D. Ao and C. Arata and F. Archilli and Zaratsyan Areg and Matteo Argenton and S. Arguedas Cuendis and Lisa Arnone and M. Artuso and E. Aslanides and R. Ataíde Da Silva and M. Atzeni and B. Audurier and Juliette Authier and D. Bacher and I. Bachiller and S. Bachmann and Marie Bachmayer and John J Back and Z. B. Bai and V. Balagura and A Balboni and W. Baldini and Zachary Baldwin and Luca Balzani and H. Bao and J. Baptista de Souza Leite and C. Barbero Pretel and M. Barbetti and I. R. Barbosa and Roger John Barlow and Mikhail Barnyakov},
  journal = {Physical Review Letters},
  year = {2026},
  month = jun,
  doi = {10.1103/dmv6-7gdv},
  url = {https://doi.org/10.1103/dmv6-7gdv},
  note = {CC BY},
}

TY  - JOUR
TI  - Observation of the Doubly Charmed Baryon Ξ c c + with the LHCb Run 3 Detector
AU  - R. Aaij
AU  - M. Abdelfatah
AU  - A. S. W. Abdelmotteleb
AU  - Carlos Abellán Beteta
AU  - C. Abellán Beteta
AU  - T. Ackernley
AU  - A. A. Adefisoye
AU  - B. Adeva
AU  - M. Adinolfi
AU  - P. Adlarson
AU  - C. Agapopoulou
AU  - C. Aidala
AU  - S. Akar
AU  - K. Carvalho Akiba
AU  - P. Albicocco
AU  - J. Albrecht
AU  - R. Aleksiejūnas
AU  - F. Alessio
AU  - P. Álvarez Cartelle
AU  - S. Amato
AU  - J. L. Amey
AU  - Y. Amhis
AU  - L. An
AU  - L. Anderlini
AU  - M. Andersson
AU  - P. Andreola
AU  - M. Andreotti
AU  - Sergio Andres Estrada
AU  - Alessia Anelli
AU  - D. Ao
AU  - C. Arata
AU  - F. Archilli
AU  - Zaratsyan Areg
AU  - Matteo Argenton
AU  - S. Arguedas Cuendis
AU  - Lisa Arnone
AU  - M. Artuso
AU  - E. Aslanides
AU  - R. Ataíde Da Silva
AU  - M. Atzeni
AU  - B. Audurier
AU  - Juliette Authier
AU  - D. Bacher
AU  - I. Bachiller
AU  - S. Bachmann
AU  - Marie Bachmayer
AU  - John J Back
AU  - Z. B. Bai
AU  - V. Balagura
AU  - A Balboni
AU  - W. Baldini
AU  - Zachary Baldwin
AU  - Luca Balzani
AU  - H. Bao
AU  - J. Baptista de Souza Leite
AU  - C. Barbero Pretel
AU  - M. Barbetti
AU  - I. R. Barbosa
AU  - Roger John Barlow
AU  - Mikhail Barnyakov
PY  - 2026
DA  - 2026/06/09
JO  - Physical Review Letters
DO  - 10.1103/dmv6-7gdv
UR  - https://doi.org/10.1103/dmv6-7gdv
AB  - The first observation of the doubly charmed baryon Ξ_{cc}^{+} is reported through its decay to the Λ_{c}^{+}K^{-}π^{+} final state, with a statistical significance exceeding seven standard deviations. The observation is made using proton-proton collision data collected in 2024 with the LHCb Run 3 detector at a center-of-mass energy of 13.6 TeV, corresponding to a total integrated luminosity of 6.9 fb^{-1}. The Ξ_{cc}^{+} mass is measured to be 3619.97±0.83±0.26_{-1.30}^{+1.90} MeV/c^{2}, where the first uncertainty is statistical, the second is systematic, and the third is due to the unknown Ξ_{cc}^{+} lifetime, which is assumed to lie in the range 15-160 fs with a baseline value of 45 fs. The difference between the masses of the Ξ_{cc}^{+} and Ξ_{cc}^{++} baryons is determined to be -1.77±0.84±0.15_{-1.30}^{+1.90} MeV/c^{2}. This is the first observation of a new particle made with the LHCb Run 3 detector.
SN  - 0031-9007
SN  - 1079-7114
SN  - 1092-0145
ER  -