Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at $\sqrt{s}$=8 TeV

• Main Author: CMS collaboration (2135 authors)
• Publication Date: 2014
• Other Authors: Hollar, Jonathan, Nayak, Aruna, Calpas, Betty, Bargassa, Pedrame, Beirão Da Cruz E Silva, Cristóvão, Faccioli, Pietro, Ferreira Parracho, Pedro Guilherme, Gallinaro, Michele, Nguyen, Federico, Rodrigues Antunes, Joao, Seixas, Joao, Varela, Joao, Vischia, Pietro, Lloret Iglesias, Lara, David Tinoco Mendes, Andre, Musella, Pasquale, Silva, Pedro, Pela, Joao, Leonardo, Nuno
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://dx.doi.org/10.1016/j.physletb.2014.07.053; http://hdl.handle.net/10400.26/26585

A 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.