Search for standard model production of four top quarks in proton–proton collisions at
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Author(s)
CMS Collaboration
Abercrombie, Daniel Robert
Allen, Brandon Leigh
Apyan, Aram
Azzolini, Virginia
Barbieri, Richard Alexander
Baty, Austin Alan
Bi, Ran
Bierwagen, Katharina
Brandt, Stephanie Akemi
Date Issued
June 2017
Journal
Physics Letters B
Publisher
Elsevier
Citation
Sirunyan, A.M. et al. “Search for Standard Model Production of Four Top Quarks in Proton–proton Collisions At √s = 13 TeV.” Physics Letters B 772 (September 2017): 336–358 © 2017 The Author(s)
Version
Final published version
Abstract
A search for events containing four top quarks (tt¯tt¯) is reported from proton–proton collisions recorded by the CMS experiment at √s = 13 TeV and corresponding to an integrated luminosity of 2.6 fb⁻¹. The analysis considers the single-lepton (e or μ)+jets and the opposite-sign dilepton (μ⁺μ⁻, μ±e∓, or e⁺e⁻)+jets channels. It uses boosted decision trees to combine information on the global event and jet properties to distinguish between tt¯tt¯ and tt¯ production. The number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions, and an upper limit is set on the cross section for tt¯tt¯ production in the standard model of 94 fb at 95% confidence level (10.2 × the prediction), with an expected limit of 118 fb. This is combined with the results from the published CMS search in the same-sign dilepton channel, resulting in an improved limit of 69 fb at 95% confidence level (7.4 × the prediction), with an expected limit of 71 fb. These are the strongest constraints on the rate of tt¯tt¯ production to date. Keywords: CMS; Physics; Top; BSM
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1016/J.PHYSLETB.2017.06.064
