LHCb CollaborationAlves Junior, Antonio AugustoBoente García, ÓscarBorsato, MartinoChobanova, VeronikaCid Vidal, XabierDosil Suárez, ÁlvaroFernández Prieto, AntonioGallas Torreira, Abraham AntonioGarcía Plana, BeatrizLucio Martínez, MiriamMartínez Santos, DiegoPrisciandaro, James J.Ramos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, María2020-05-122020-05-122018Aaij, R., Adeva, B., Adinolfi, M. et al. Observation of the decay Λ 0b → ψ(2S)pπ−. J. High Energ. Phys. 2018, 131 (2018). https://doi.org/10.1007/JHEP08(2018)1311029-8479http://hdl.handle.net/10347/22215The Cabibbo-suppressed decay Λ 0b → ψ(2S)pπ− is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb−1 of integrated luminosity at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The ψ(2S) mesons are reconstructed in the μ+μ− final state. The branching fraction with respect to that of the Λ 0b → ψ(2S)pK− decay mode is measured to be B(Λ0b→ψ(2S)pπ−)B(Λ0b→ψ(2S)pK−)=(11.4±1.3±0.2)%, where the first uncertainty is statistical and the second is systematic. The ψ(2S)p and ψ(2S)π− mass spectra are investigated and no evidence for exotic resonances is found.eng© CERN, for the benefit of the LHCb Collaboration. Article funded by SCOAP3. This article is distributed under the terms of the Creative CommonsAttribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedhttps://creativecommons.org/licenses/by/4.0/B physicsFlavor physicsHadron-Hadron scattering (experiments)Spectroscopyjournal article10.1007/JHEP08(2018)131open access