LHCb CollaborationAdeva Andany, BernardoÁlvarez Cartelle, PaulaAlves, António AugustoBoente García, ÓscarChobanova, VeronikaCid Vidal, XabierDalseno, JeremyDosil Suárez, ÁlvaroFernández Prieto, AntonioGallas Torreira, AbrahamGarcía Plana, BeatrizLucio Martínez, M.Martínez Santos, DiegoPló Casasús, MáximoProuve, ClaireRamos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, María2026-01-142026-01-142019-07-05The LHCb collaboration., Aaij, R., Abellán Beteta, C. et al. Amplitude analysis of the B0 (s) → K∗0K∗0 decays and measurement of the branching fraction of the B0 → K∗0K∗0 decay. J. High Energ. Phys. 2019, 32 (2019). https://doi.org/10.1007/JHEP07(2019)032https://hdl.handle.net/10347/45136The B0 → K∗0K∗0 and Bs0 → K∗0K∗0 decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3fb−1. An untagged and time- integrated amplitude analysis of B0 → (K+π−)(K−π+) decays in two-body invariant (s) mass regions of 150MeV/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 Bs0 → 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)) × 10−7eng© 2019, The Author(s). This is an open access article distributed under the terms of the Creative Commons CC BY licenseAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/B physicsHadron-Hadron scattering (experiments)journal article10.1007/JHEP07(2019)0321029-8479open access