Abstract
A search for supersymmetry is presented based on proton-proton collision events containing identified hadronically decaying top quarks, no leptons, and an imbalance $p_\mathrm{T}^\text{miss}$ in transverse momentum. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 35.9 fb$^{-1}$. Search regions are defined in terms of the multiplicity of bottom quark jet and top quark candidates, the $p_\mathrm{T}^\text{miss}$, the scalar sum of jet transverse momenta, and the $m_{\mathrm{T2}}$ mass variable. No statistically significant excess of events is observed relative to the expectation from the standard model. Lower limits on the masses of supersymmetric particles are determined at 95% confidence level in the context of simplified models with top quark production. For a model with direct top squark pair production followed by the decay of each top squark to a top quark and a neutralino, top squark masses up to 1020 GeV and neutralino masses up to 430 GeV are excluded. For a model with pair production of gluinos followed by the decay of each gluino to a top quark-antiquark pair and a neutralino, gluino masses up to 2040 GeV and neutralino masses up to 1150 GeV are excluded. These limits extend previous results.
Highlights
The observation [1,2,3] of a Higgs boson (H) has been the most significant discovery to date at the CERN LHC
Systematic uncertainties in the prediction for the tt, single top quark, and W þ jets background are evaluated from the following sources, based on the uncertainties in the respective quantities: the statistical uncertainty in the translation factors (1–40% depending on the search region), the lepton reconstruction and isolation efficiency (7–43%), the jet and pmT iss energy scale and resolution, the initial-state radiation (ISR) modeling, the parton distribution functions (PDFs), and the b jet tagging efficiency (1%)
Results are presented from a search for direct and gluinomediated top squark production in proton-proton collisions at a center-of-mass energy of 13 TeV
Summary
The observation [1,2,3] of a Higgs boson (H) has been the most significant discovery to date at the CERN LHC. The largest source of SM background arises from top quark-antiquark pair (tt), single top quark, and W þ jets production, namely from events in which a leptonically decaying W boson yields both a high-momentum neutrino, generating pmT iss, and a charged lepton that is either not identified, not reconstructed, or outside the analysis acceptance. Another important source of background is Z þ jets production followed by Z → ννdecay. They exhibit common features, such as the presence of multiple top quarks and two LSPs
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