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oai:recercat.cat:2445/1328462025-12-04T21:32:24Zcom_2072_1057col_2072_478812col_2072_478823col_2072_478904col_2072_478917

00925njm 22002777a 4500 dc Badalov, Alexey author Calvo Gómez, Míriam author Camboni, Alessandro author Coquereau, Samuel author Garrido Beltrán, Lluís author Gascón Fora, David author Graciani Díaz, Ricardo author Graugés Pous, Eugeni author Marin Benito, Carla author Picatoste Olloqui, Eduardo author Rives Molina, Vicente José author Vilasis-Cardona, Xavier author LHCb Collaboration author 2019-05-08T09:44:39Z 2019-05-08T09:44:39Z 2017-02-21 2019-05-08T09:44:39Z A search for the B0→K+K- decay is performed using p p -collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0 and 2.0 fb-1 at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the Bs0→π+π- decay. The measured branching fractions are B (B0→K+K- )=(7.80 ±1.27 ±0.81 ±0.21 )×10-8 and B (Bs0→π+π- )=(6.91 ±0.54 ±0.63 ±0.19 ±0.40 )×10-7 . The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the B0→K+π- branching fraction used as a normalization. For the Bs0 mode, the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into Bs0 and B0 mesons. Física de partícules Experiments Particle physics Experiments Observation of the Annihilation Decay Mode B0→K+K−