Alfonso Albero, AlejandroCalvo Gómez, MíriamCamboni, AlessandroCoquereau, SamuelGarcía Moreno, PaulaGarrido Beltrán, LluísGascón Fora, DavidGironella Gironell, PereGolobardes, ElisabetGómez Fernández, S.Graciani Díaz, RicardoGraugés Pous, EugeniManera Escalero, R.Mauricio, J.Vilasis-Cardona, XavierLHCb Collaboration2021-03-102021-03-102020-09-221550-7998https://hdl.handle.net/2445/174858The first observation of the decay B0→D0¯D0K+π− is reported using proton-proton collision data corresponding to an integrated luminosity of 4.7  fb−1 collected by the LHCb experiment in 2011, 2012 and 2016. The measurement is performed in the full kinematically allowed range of the decay outside of the D*− region. The ratio of the branching fraction relative to that of the control channel B0→D*−D0K+ is measured to be R=(14.2±1.1±1.0)%, where the first uncertainty is statistical and the second is systematic. The absolute branching fraction of B0→D0¯D0K+π− decays is thus determined to be B(B0→D0¯D0K+π−)=(3.50±0.27±0.26±0.30)×10−4, where the third uncertainty is due to the branching fraction of the control channel. This decay mode is expected to provide insights to spectroscopy and the charm-loop contributions in rare semileptonic decays.11 p.application/pdfengcc-by (c) Aaij, R. et al., 2020http://creativecommons.org/licenses/by/3.0/es/Gran Col·lisionador d'HadronsMesons (Física nuclear)Large Hadron Collider (France and Switzerland)Mesons (Nuclear physics)info:eu-repo/semantics/article7064772021-03-10info:eu-repo/semantics/openAccess