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oai:recercat.cat:2445/1333302025-12-05T16:59:16Zcom_2072_1057col_2072_478823col_2072_478904col_2072_478917

00925njm 22002777a 4500 dc Badalov, Alexey author Calvo Gómez, Míriam author Camboni, Alessandro author Comerma Montells, Albert author Garrido Beltrán, Lluís author Graciani Díaz, Ricardo author Graugés Pous, Eugeni author Oyanguren Campos, Arantza de author Pérez-Calero Yzquierdo, Antonio author Picatoste Olloqui, Eduardo author Potterat, Cédric author Rives Molina, Vicente José author Ruiz, Hugo (Ruiz Pérez) author Ruiz Valls, Pablo author Vilasis-Cardona, Xavier author LHCb Collaboration author 2019-05-16T15:19:09Z 2019-05-16T15:19:09Z 2013-09-05 2019-05-16T15:19:10Z A search for the rare decays B 0 s → μ + μ − and B 0 → μ + μ − is performed at the LHCb experiment. The data analyzed correspond to an integrated luminosity of 1     fb − 1 of p p collisions at a center-of-mass energy of 7 TeV and 2     fb − 1 at 8 TeV. An excess of B 0 s → μ + μ − signal candidates with respect to the background expectation is seen with a significance of 4.0 standard deviations. A time-integrated branching fraction of B ( B 0 s → μ + μ − ) = ( 2.9 + 1.1 − 1.0 ) × 10 − 9 is obtained and an upper limit of B ( B 0 → μ + μ − ) < 7.4 × 10 − 10 at 95% confidence level is set. These results are consistent with the standard model expectations. Física de partícules Experiments Particle physics Experiments Measurement of the B0s→μ+μ− Branching Fraction and Search for B0→μ+μ− Decays at the LHCb Experiment