LHCb CollaborationAlfonso Albero, AlejandroCalvo Gómez, MíriamCamboni, AlessandroCoquereau, SamuelGarrido Beltrán, LluísGascón Fora, DavidGironella Gironell, PereGraciani Díaz, RicardoGraugés Pous, EugeniVilasis-Cardona, XavierMarin Benito, Carla2020-05-252020-05-252019-07-051126-6708https://hdl.handle.net/2445/162300The B0→K∗0K¯¯¯¯¯∗0 and B0s→K∗0K¯¯¯¯¯∗0 decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1. An untagged and timeintegrated amplitude analysis of B 0(s)  → (K+π−)(K−π+) decays in two-body invariant mass regions of 150 MeV/c2 around the K∗0 mass is performed. A stronger longitudinal polarisation fraction in the B0→K∗0K¯¯¯¯¯∗0 decay, fL = 0.724 ± 0.051 (stat) ± 0.016 (syst), is observed as compared to fL = 0.240 ± 0.031 (stat) ± 0.025 (syst) in the B0s→K∗0K¯¯¯¯¯∗0 decay. The ratio of branching fractions of the two decays is measured and used to determine B(B0→K∗0K¯¯¯¯¯∗0)=(8.0±0.9(stat)±0.4(syst))×10−7.application/pdfengcc-by (c) LHCb Collaboration et al., 2019http://creativecommons.org/licenses/by/3.0/esHadronsFísica de partículesExperimentsHadronsParticle physicsExperimentsinfo:eu-repo/semantics/article6963412020-05-25info:eu-repo/semantics/openAccess