Measurement of $tW$ Differential Cross Section with the ATLAS Detector at 13 TeV

The cross-section to produce a $W$ boson in association with a top quark is measured differentially with respect to several particle-level final-state observable quantities. The measurements are performed using $36.1$~\mbox{fb$^{-1}$} of $pp$ collision data with $\sqrt{s}=13~\mathrm{TeV}$ collected in 2015 and 2016. Cross-sections are measured in a fiducial phase-space defined by the presence of two charged leptons and exactly one jet identified as containing $B$ hadrons. Measurements are normalised to the fiducial cross-section, causing several of the main uncertainties to cancel. Results are found to be in good agreement with predictions from several Monte Carlo generators.