LHCb CollaborationAdeva Andany, BernardoAlves Junior, Antonio AugustoBoente García, ÓscarBorsato, MartinoChobanova, VeronikaCid Vidal, XabierDosil Suárez, ÁlvaroFernández Prieto, AntonioGallas Torreira, Abraham AntonioGarcía Plana, BeatrizLucio Martínez, MiriamMartínez Santos, DiegoPlo Casasus, MáximoPrisciandaro, James J.Ramos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, María2020-05-142020-05-142018Aaij, R., Adeva, B., Adinolfi, M. et al. Observation of the decay B¯0s→χc2K+K− in the ϕ mass region. J. High Energ. Phys. 2018, 191 (2018). https://doi.org/10.1007/JHEP08(2018)1911029-8479http://hdl.handle.net/10347/22307The B¯0s→χc2K+K− decay mode is observed and its branching fraction relative to the corresponding χc1 decay mode, in a ±15 MeV/c2 window around the ϕ mass, is found to be B(B¯0s→χc2K+K−)B(B¯0s→χc1K+K−)=(17.1±3.1±0.4±0.9)%, where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the branching fractions of radiative χc decays. The decay mode B¯0s→χc1K+K− allows the B0s mass to be measured as m(B0s)=5366.83±0.25±0.27 MeV/c2, where the first uncertainty is statistical and the second systematic. A combination of this result with other LHCb determinations of the B 0s mass is made.eng© CERN, for the benefit of the LHCb Collaboration. Article funded by SCOAP3. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.https://creativecommons.org/licenses/by/4.0/Flavor physicsB physicsHadron-Hadron scattering (experiments)journal article10.1007/JHEP08(2018)191open access