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A search for electroweak production of a single vectorlike $T$quark in association with a bottom ( $b$) quark in the all-hadronic decay channel is presented. This search uses proton-proton collision data at $\sqrt{s}=13\mathrm{TeV}$collected by the CMS experiment at the CERN LHC during 2016–2018, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. The $T$quark is assumed to have charge $2/3$and decay to a top ( $t$) quark and a Higgs ( $H$) or $Z$boson. Hadronic decays of the $t$quark and the $H$or $Z$boson are reconstructed from the kinematic properties of jets, including those containing $b$hadrons. No deviation from the standard model prediction is observed in the reconstructed $tH$and $tZ$invariant mass distributions. The 95% confidence level upper limits on the product of the production cross section and branching fraction of a $T$quark produced in association with a $b$quark and decaying via $tH$or $tZ$range from 1260 to 68 fb for $T$quark masses of 600–1200 GeV. © 2024 CERN, for the CMS Collaboration2024CERN 

A bstract A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016–2018, with an integrated luminosity of 138 fb − 1 . Events are separated into single-lepton, same-sign charge dilepton, and multi-lepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for $$ \textrm{T}\overline{\textrm{T}} $$ T T ¯ production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for $$ \textrm{B}\overline{\textrm{B}} $$ B B ¯ production with B quark decays to tW.