Measurement and interpretations of $W^±$Z cross-sections in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

Measurements of integrated and differential cross-sections for 𝑊±𝑍 production in proton–proton collisions are presented. The data collected by the ATLAS detector at the Large Hadron Collider from 2015 to 2018 at a centre-of-mass energy of √𝑠 = 13 TeV are used, corresponding to an integrated luminosity of 140 fb−1 . The 𝑊±𝑍 candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons or muons. The integrated cross-section for the production of 𝑊±𝑍 is measured in the detector fiducial region. The 𝑊±𝑍 production is also measured differentially as functions of various kinematic variables, including new observables sensitive to CP-violation effects. All measurements are compared with state-of-the-art Standard Model predictions from fixed-order calculations or Monte Carlo generators based on next-to-leading-order matrix elements interfaced with parton showers. An effective field theory interpretation of the measurements is performed, considering both CP-conserving and CP-violating dimension-6 operators modifying the 𝑊±𝑍 production. Limits on CP-conserving Wilson coefficients are extracted using the transverse mass of the 𝑊±𝑍 system. For CP-violating coefficients a machine learning approach is used to construct an observable with enhanced sensitivity to CP-violation effects.