First Observation of the B ¯ s0 → Λc+ Λ ¯ c- Decay and Evidence for the B ¯ 0 → Λc+ Λ ¯ c- Decay

Aaij, R.; Abdelmotteleb, A. S.W.; Abellan Beteta, C.; Abudinén, F.; Ackernley, T.; Adefisoye, A. A.; Adeva, B.; Adinolfi, M.; Adlarson, P.; Agapopoulou, C.; Aidala, C. A.; Ajaltouni, Z.; Akar, S.; Akiba, K.; Akthar, M.; Albicocco, P.; Albrecht, J.; Aleksiejunas, R.; Alessio, F.; Alvarez Cartelle, P.; Amalric, R.; Amato, S.; Amey, J. L.; Amhis, Y.; An, L.; Anderlini, L.; Andersson, M.; Andreola, P.; Andreotti, M.; Andres Estrada, S.; Anelli, A.; Ao, D.; Arata, C.; Archilli, F.; Areg, Z.; Argenton, M.; Arguedas Cuendis, S.; Arnone, L.; Artamonov, A.; Artuso, M.; Aslanides, E.; Ataíde Da Silva, R.; Atzeni, M.; Audurier, B.; Authier, J. A.; Bacher, D.; Bachiller Perea, I.; Bachmann, S.; Bachmayer, M.; Back, J. J.; Baladron Rodriguez, P.; Balagura, V.; Balboni, A.; Baldini, W.; Baldwin, Z.; Balzani, L.; Bao, H.; Baptista De Souza Leite, J.; Barbero Pretel, C.; Barbetti, M.; Barbosa, I. R.; Barlow, R. J.; Barnyakov, M.; Barsuk, S.; Barter, W.; Bartz, J.; Bashir, S.; Batsukh, B.; Battista, P. B.; Bavarchee, A.; Bay, A.; Beck, A.; Becker, M.; Bedeschi, F.; Bediaga, I. B.; Behling, N. A.; Belin, S.; Bellavista, A.; Belous, K.; Belov, I.; Belyaev, I.; Benane, G.; Bencivenni, G.; Ben-Haim, E.; Berezhnoy, A.; Bernet, R.; Bernet Andres, S.; Bertolin, A.; Betti, F.; Bex, J.; Bezshyyko, O.; Bhattacharya, S.; Bieker, M. S.; Biesuz, N. V.; Biolchini, A.; Birch, M.; Bishop, F. C.R.; Bitadze, A.; Bizzeti, A.; Blake, T.; et al.

doi:10.1103/cxn3-8t4g

research article

First Observation of the B ¯ s0 → Λc+ Λ ¯ c- Decay and Evidence for the B ¯ 0 → Λc+ Λ ¯ c- Decay

Aaij, R.

•

Abdelmotteleb, A. S.W.

•

Abellan Beteta, C.

February 13, 2026

Physical Review Letters

A search is presented for the two-body charmed baryonic decays, B¯(s)0→Λc+Λ¯c-, using a data sample collected by the LHCb experiment during 2011-2012 and 2015-2018, corresponding to an integrated luminosity of 9 fb-1. The first observation of the B¯s0→Λc+Λ¯c- decay is reported with 6.2σ significance along with 4.3σ evidence for the B¯0→Λc+Λ¯c- decay. The branching fractions are measured to be B(B¯0→Λc+Λ¯c-)=(1.01-0.28+0.27±0.08±0.15)×10-5 and B(B¯s0→Λc+Λ¯c-)=(5.0±1.3±0.5±0.8)×10-5, where the first uncertainty is statistical, the second systematic, and the third due to external inputs. These results provide novel experimental inputs for the theoretical framework describing two-body baryonic decays of B mesons via W-emission and W-exchange mechanisms.

Cite this item

Aaij, R., Abdelmotteleb, A. S. W., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adefisoye, A. A., Adeva, B., Adinolfi, M., Adlarson, P., Agapopoulou, C., Aidala, C. A., Ajaltouni, Z., Akar, S., Akiba, K., Akthar, M., Albicocco, P., Albrecht, J., Aleksiejunas, R., Alessio, F., et al. (2026). First Observation of the B ¯ s0 → Λc+ Λ ¯ c- Decay and Evidence for the B ¯ 0 → Λc+ Λ ¯ c- Decay. Physical Review Letters, 136(6), Article 061802. https://doi.org/10.1103/cxn3-8t4g

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