Measurement of the Single Top tW Inclusive Cross Section in the Single Lepton Final State at 13 TeV with ATLAS

Single top-quark production in association with a W boson (known as the tW channel) can be measured in the ATLAS detector at the Large Hadron Collider. In general, single top-quark cross-section measurements allow for a precise test of Standard Model physics and can aid in the discovery of new physics (i.e. FCNC, anomalous couplings, ...). The tW channel has the second largest cross-section of the three main single top production processes at the LHC and it is sensitive to different new physics from that of the s- and t-channels. In this work, tW production is studied in the lepton plus jets channel by selecting events with three jets, one lepton and some amount of missing transverse momentum. Separation of signal and background events is performed by a neural network trained on Monte Carlo samples. This training helps identify the tW signal from its more prominent backgrounds, top-quark pair production and W plus jets events, which share similar signatures but have much greater cross-sections. Lastly, a likelihood fit is used to extract the signal cross-section.