Abstract
Results are reported from a search for supersymmetry in pp collisions at a center-of-mass energy of 8 TeV, based on events with a single isolated lepton (electron or muon) and multiple jets, at least two of which are identified as b jets. The data sample corresponds to an integrated luminosity of 19.3 fb−1recorded by the CMS experiment at the LHC in 2012. The search is motivated by supersymmetric models that involve strong-production processes and cascade decays of new particles. The resulting final states contain multiple jets as well as missing transverse momentum from weakly interacting particles. The event yields, observed across several kinematic regions, are consistent with the expectations from standard model processes. The results are interpreted in the context of simplified supersymmetric scenarios with pair production of gluinos, where each gluino decays to a top quark–antiquark pair and the lightest neutralino. For the case of decays via virtual top squarks, gluinos with a mass smaller than 1.26 TeV are excluded for low neutralino masses.
Highlights
This paper presents results from a search for new physics in proton-proton collisions at a centerof-mass energy of 8 TeV in events with a single lepton, missing transverse momentum, and multiple jets, at least two of which are tagged as originating from bottom quarks (b-tagged jets)
The background prediction method is validated with the 3 ≤ Nj ≤ 5 control sample, which is background dominated with dilepton tt events and with a relative contribution from W+jets larger than in the signal region
A sample of proton-proton collisions recorded with the Compact Muon Solenoid (CMS) detector at a center-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 19.3 fb−1 has been used for a search for new physics in events with a single isolated electron or muon, multiple high-pT jets, including identified b jets, and missing transverse momentum
Summary
This paper presents results from a search for new physics in proton-proton collisions at a centerof-mass energy of 8 TeV in events with a single lepton (electron or muon), missing transverse momentum, and multiple jets, at least two of which are tagged as originating from bottom quarks (b-tagged jets) This signature arises in models based on supersymmetry (SUSY) [1,2,3,4,5,6], which potentially offers natural solutions to limitations of the standard model (SM). It focuses on gluino pair production, with subsequent gluino decay to two top quarks and the LSP (χ01) through either a virtual or an on-shell top squark: pp → gg with g(→ tt) → ttχ01 These decay chains result in events with high jet multiplicity, four b quarks in the final state, and large missing transverse momentum (E/T). In this approach combined signal regions for the e and the μ channels are used since the differences in terms of backgrounds and sensitivity are small
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