Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at √s = 8 TeV

• Main Authors: Apyan, Aram (Contributor), Barbieri, Richard Alexander (Contributor), Bauer, Gerry P. (Contributor), Busza, Wit (Contributor), Cali, Ivan Amos (Contributor), Chan, M. (Contributor), Di Matteo, Leonardo (Contributor), Dutta, Valentina (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Gulhan, Doga Can (Contributor), Klute, Markus (Contributor), Lai, Yue Shi (Contributor), Lee, Yen-Jie (Contributor), Luckey, P. David (Contributor), Ma, T. (Contributor), Paus, Christoph M. E. (Contributor), Ralph, Duncan Kelley (Contributor), Roland, Christof E. (Contributor), Roland, Gunther M. (Contributor), Stephans, George S. F. (Contributor), Stoeckli, Fabian (Contributor), Sumorok, Konstanty C. (Contributor), Velicanu, Dragos Alexandru (Contributor), Veverka, Jan (Contributor), Wyslouch, Boleslaw (Contributor), Yang, M. (Contributor), Zanetti, Marco (Contributor), Zhukova, Victoria (Contributor), ATLAS Collaboration (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: Elsevier B.V., 2014-10-27T15:01:23Z.
• Subjects: Article
• Online Access: Get fulltext

 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 √s=8 TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb[superscript −1]. 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 t˜2 decaying to a lighter top-squark mass eigenstate t˜1 via either ˜2→Ht˜1 or t˜2→Zt˜1, followed in both cases by t˜1→tχ˜10, where χ˜10 is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between thet˜1 and χ˜10 states is approximately equal to the top-quark mass (m[subscript t˜1]−mχ˜10≃mt), which is not probed by searches for direct t˜1 squark pair production. The analysis excludes top squarks with masses m[subscript t˜2]<575 GeV and m[subscript t˜1]<400 GeV at a 95% confidence level.