Electroweak Production of Two Opposite-Sign W Bosons using the ATLAS Detector

Two studies involving the production of two opposite-sign W-bosons are performed using proton-proton collisions at $\sqrt{s} = 13$ TeV recorded by the ATLAS experiment at the Large Hadron Collider (LHC). For the first study, the two W-bosons are produced in association with no jets as a result of interactions between quarks and gluons. Once produced, the W-boson pair decays leptonically ($W^{+}W^{-} \rightarrow e^{+} \mu^{-} \nu_{e} \bar{\nu}_{\mu}$ or $W^{+}W^{-} \rightarrow \mu^{+} e^{-} \nu_{\mu} \bar{\nu}_{e}$). Measurements of the fiducial and differential cross sections are performed for this set of processes using data collected in 2015--2016 at a total integrated luminosity of $\mathscr{L} = 36.1$ $fb^{-1}$. The differential cross section is measured as a function of six observables. The measured fiducial and differential cross sections for this set of processes are compared with several theoretical predictions and several past measurements involving this process. Building on the results of the first study, the second study focuses on the electroweak production of two W-bosons in association with at least two jets. Once produced, the W-boson pair decays leptonically ($W^{+}W^{-} \rightarrow e^{+}e^{-} \nu_{e}\bar{\nu}_{e}$, $W^{+}W^{-} \rightarrow \mu^{+} \mu^{-} \nu_{\mu}\bar{\nu}_{\mu}$, $W^{+}W^{-} \rightarrow e^{+} \mu^{-} \nu_{e}\bar{\nu}_{\mu}$ or $W^{+}W^{-} \rightarrow \mu^{+} e^{-} \nu_{\mu}\bar{\nu}_{e}$). This study uses discovery significance and a set of optimized and trained neural networks to determine the viability of performing a cross section measurement for this process using the full Run 2 (2015--2018) dataset collected by ATLAS