Search for top-squark pair production in final states with one lepton, jets, and missing transverse momentum using 36 fb−1 of √s=13 TeV pp collision data with the ATLAS detector

• Autor(a) principal: Santos, S. P. Amor dos
• Data de Publicação: 2018
• Outros Autores: Fiolhais, M. C. N., Galhardo, B., Veloso, F., Wolters, H., ATLAS Collaboration
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/107725; https://doi.org/10.1007/JHEP06(2018)108
• topic: Hadron-Hadron scattering (experiments)

The results of a search for the direct pair production of top squarks, the supersymmetric partner of the top quark, in nal states with one isolated electron or muon, several energetic jets, and missing transverse momentum are reported. The analysis also targets spin-0 mediator models, where the mediator decays into a pair of dark-matter particles and is produced in association with a pair of top quarks. The search uses data from proton-proton collisions delivered by the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of ps = 13TeV and recorded by the ATLAS detector, corresponding to an integrated luminosity of 36 fb1. A wide range of signal scenarios with di erent mass-splittings between the top squark, the lightest neutralino and possible intermediate supersymmetric particles are considered, including cases where the W bosons or the top quarks produced in the decay chain are o -shell. No signi cant excess over the Standard Model prediction is observed. The null results are used to set exclusion limits at 95% con dence level in several supersymmetry benchmark models. For pair-produced topsquarks decaying into top quarks, top-squark masses up to 940 GeV are excluded. Stringent exclusion limits are also derived for all other considered top-squark decay scenarios. For the spin-0 mediator models, upper limits are set on the visible cross-section.