Measurement of the production cross section for single top quarks in association with W bosons in pp collisions at $\sqrt{s}=13~\mathrm{TeV}$

A measurement of the associated production of a single top quark and a W boson in pp collisions at $\sqrt{s}=13~\mathrm{TeV}$ with the CMS experiment at the CERN LHC is presented. The data set, collected in 2016, corresponds to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. The measurement is performed in the dilepton final state, using events with one electron and one muon. A multivariate discriminant, exploiting kinematic properties of events, is used to separate the signal from the dominant ${\rm t\bar{t}}$ background. The measured cross section of $\sigma = 63.1 \pm 1.8~({\rm stat}) \pm 6.0~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is in agreement with the standard model expectation.