Badalov, AlexeyCalvo Gómez, MíriamGarrido Beltrán, LluísGascón Fora, DavidGraciani Díaz, RicardoGraugés Pous, EugeniMarin Benito, CarlaPicatoste Olloqui, EduardoRives Molina, Vicente JoséVilasis-Cardona, XavierLHCb Collaboration2019-05-092019-05-092015-12-110031-9007https://hdl.handle.net/2445/132910Using a p p collision data sample corresponding to an integrated luminosity of 3.0     fb − 1 , collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξ − b → Λ 0 b π − . No b hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be f Ξ − b f Λ 0 b B ( Ξ − b → Λ 0 b π − ) = ( 5.7 ± 1. 8 + 0.8 − 0.9 ) × 10 − 4 , where f Ξ − b and f Λ 0 b are the b → Ξ − b and b → Λ 0 b fragmentation fractions, and B ( Ξ − b → Λ 0 b π − ) is the branching fraction. Assuming f Ξ − b / f Λ 0 b is bounded between 0.1 and 0.3, the branching fraction B ( Ξ − b → Λ 0 b π − ) would lie in the range from ( 0.57 ± 0.21 ) % to ( 0.19 ± 0.07 ) % .10 p.application/pdfengcc by (c) CERN; LHCb Collaboration, 2015http://creativecommons.org/licenses/by/3.0/es/Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6567672019-05-09info:eu-repo/semantics/openAccess