LHCb CollaborationAdeva Andany, BernardoBorsato, MartinoChobanova, VeronikaCid Vidal, XabierDosil Suárez, ÁlvaroFernández Prieto, AntonioGallas Torreira, Abraham AntonioGarcía Pardiñas, JuliánLemos Cid, EdgarLucio Martínez, MiriamMartínez Santos, DiegoPlo Casasus, MáximoPrisciandaro, JessicaRamos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, MaríaVázquez Sierra, Carlos2020-05-282020-05-282017Aaij, R., Adeva, B., Adinolfi, M. et al. Observation of the decay B0s → η c ϕ and evidence for B0s → η c π + π − . J. High Energ. Phys. 2017, 21 (2017). https://doi.org/10.1007/JHEP07(2017)0211029-8479http://hdl.handle.net/10347/22666A study of B0s → η c ϕ and B0s → η c π + π − decays is performed using pp collision data corresponding to an integrated luminosity of 3.0 fb−1, collected with the LHCb detector in Run 1 of the LHC. The observation of the decay B 0s → η c ϕ is reported, where the η c meson is reconstructed in the pp¯, K + K − π + π −, π + π − π + π − and K + K − K + K − decay modes and the ϕ(1020) in the K + K − decay mode. The decay B 0s → J/ψϕ is used as a normalisation channel. Evidence is also reported for the decay B 0s → η c π + π −, where the η c meson is reconstructed in the pp¯decay mode, using the decay B 0s → J/ψπ + π − as a normalisation channel. The measured branching fractions are B(B0s→ηcϕ)=(5.01±0.53±0.27±0.63)×10−4,B(B0s→ηcπ+π−)=(1.76±0.59±0.12±0.29)×10−4, where in each case the first uncertainty is statistical, the second systematic and the third uncertainty is due to the limited knowledge of the external branching fractions.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 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.https://creativecommons.org/licenses/by/4.0B physicsBranching fractionFlavor physicsHadron-Hadron scattering (experiments)journal article10.1007/JHEP07(2017)021open access