Karapınar, GülerCMS Collaboration2022-08-152022-08-1520211029-8479https://doi.org/10.1007/JHEP11(2021)111https://hdl.handle.net/11147/12382A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.eninfo:eu-repo/semantics/openAccessHadron-Hadron scattering (experiments)Article2-s2.0-8511960778010.1007/JHEP11(2021)111