Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at √s=8 TeV
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−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 t2 decaying to a lighter top-squark mass eigenstate t1 via either t2→Ht1 or t2→Zt1, followed in both cases by t1→tχ10, where χ01 is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the t1 and χ01 states is approximately equal to the top-quark mass (mt1−mχ01≃mt), which is not probed by searches for direct t1 squark pair production. The analysis excludes top squarks with masses mt2<575 GeV and mt1<400 GeV at a 95% confidence level.
CMS; SUSY; stop; Higgs