CMS collaboration (2135 authors)Hollar, JonathanNayak, ArunaCalpas, BettyBargassa, PedrameBeirão Da Cruz E Silva, CristóvãoFaccioli, PietroFerreira Parracho, Pedro GuilhermeGallinaro, MicheleNguyen, FedericoRodrigues Antunes, JoaoSeixas, JoaoVarela, JoaoVischia, PietroLloret Iglesias, LaraDavid Tinoco Mendes, AndreMusella, PasqualeSilva, PedroPela, JoaoLeonardo, Nuno2019-02-042019-02-042014-09-07http://dx.doi.org/10.1016/j.physletb.2014.07.053http://hdl.handle.net/10400.26/26585A search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton-proton collisions at sqrt(s) = 8 TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 inverse femtobarns. The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant excess of events over the standard model background prediction is observed. The results are interpreted in the context of simplified supersymmetric models with pair production of a heavier top-squark mass eigenstate stop[2] decaying to a lighter top-squark mass eigenstate stop[1] via either stop[2] to H stop[1] or stop[2] to Z stop[1], followed in both cases by stop[1] to t neutralino, where neutralino is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the stop[1] and neutralino states is approximately equal to the top-quark mass (m[stop[1]] - m[neutralino] ~= m[t]), which is not probed by searches for direct stop[1] squark pair production. The analysis excludes top squarks with masses m[stop[2]] < 575 GeV and m[stop[1]] < 400 GeV at a 95% confidence level.engjournal article2019-02-04