Comerma Montells, AlbertGarrido Beltrán, LluísGraciani Díaz, RicardoGraugés Pous, EugeniMarin Benito, CarlaPicatoste Olloqui, EduardoRives Molina, Vicente JoséRuiz, Hugo (Ruiz Pérez)LHCb Collaboration2022-05-162022-05-162014-101126-6708https://hdl.handle.net/2445/185620First observations of the rare decays B+→ K+π +π −µ +µ − and B+→ φK+µ +µ − are presented using data corresponding to an integrated luminosity of 3.0 fb−1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The branching fractions of the decays are B(B +→K+π +π −µ +µ −) = 4.36 +0.29 −0.27 (stat) ± 0.21 (syst) ± 0.18 (norm) × 10−7 , B(B +→φK+µ +µ −) = 0.82 +0.19 −0.17 (stat) +0.10 −0.04 (syst) ± 0.27 (norm) × 10−7 , where the uncertainties are statistical, systematic, and due to the uncertainty on the branching fractions of the normalisation modes. A measurement of the differential branching fraction in bins of the invariant mass squared of the dimuon system is also presented for the decay B+→ K+π +π −µ +µ −. Keywords: Rare decay, Hadron-Hadron Scattering, B physics, Flavor physi18 p.application/pdfengcc-by (c) Comerma-Montells, A. et al., 2014https://creativecommons.org/licenses/by/4.0/HadronsGran Col·lisionador d'HadronsFísica de partículesExperimentsHadronsLarge Hadron Collider (France and Switzerland)Particle physicsExperimentsinfo:eu-repo/semantics/article6457402022-05-16info:eu-repo/semantics/openAccess