LHCb CollaborationAbellan Beteta, CarlosCalvo Gómez, MíriamCamboni, AlessandroComerma Montells, AlbertGarrido Beltrán, LluísGraciani Díaz, RicardoGraugés Pous, EugeniLópez Asamar, EliasOyanguren Campos, Arantza dePicatoste Olloqui, EduardoPotterat, CédricRives Molina, Vicente JoséRuiz, Hugo (Ruiz Pérez)Ruiz Valls, PabloVázquez Gómez, RicardVilasis-Cardona, Xavier2023-03-292023-03-292013-080550-3213https://hdl.handle.net/2445/196207This paper reports the first measurement of the effective B0 s → J /ψK0 S lifetime and an updated mea- surement of its time-integrated branching fraction. Both measurements are performed with a data sample, corresponding to an integrated luminosity of 1.0 fb−1 of pp collisions, recorded by the LHCb experiment in 2011 at a centre-of-mass energy of 7 TeV. The results are: τ eff J /ψK0 S = 1.75 ± 0.12 (stat) ± 0.07 (syst) ps and B(B0 s → J /ψK0 S ) = (1.97 ± 0.23) × 10−5. For the latter measurement, the uncertainty includes both statistical and systematic sources.18 p.application/pdfengcc-by-nc-nd (c) CERN, 2013https://creativecommons.org/licenses/by-nc-nd/4.0/Física de partículesExperimentsGran Col·lisionador d'HadronsParticle physicsExperimentsLarge Hadron Collider (France and Switzerland)info:eu-repo/semantics/article6290092023-03-29info:eu-repo/semantics/openAccess