Yetkin, Elif Aslı2021-05-072021-05-072019-11-011126-6708https://hdl.handle.net/11411/3645https://doi.org/10.1007/JHEP11(2019)082A search for the standard model production of four top quarks (pp ? t t ¯ t t ¯) is reported using single-lepton plus jets and opposite-sign dilepton plus jets signatures. Proton-proton collisions are recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV in a sample corresponding to an integrated luminosity of 35.8 fb?1. A multivariate analysis exploiting global event and jet properties is used to discriminate t t ¯ t t ¯ from t t ¯ production. No significant deviation is observed from the predicted background. An upper limit is set on the cross section for t t ¯ t t ¯ production in the standard model of 48 fb at 95% confidence level. When combined with a previous measurement by the CMS experiment from an analysis of other final states, the observed signal significance is 1.4 standard deviations, and the combined cross section measurement is 13?9+11 fb. The result is also interpreted in the framework of effective field theory.eninfo:eu-repo/semantics/openAccessHadron-Hadron scattering (experiments)Top physicsArticle2-s2.0-8507610826810.1007/JHEP11(2019)082N/AWOS:000514864800001