Measurements of cross sections for the production of pairs of oppositely charged -bosons (WW) provide an important test of the Standard Model (SM), in particular electroweak theory and perturbative quantum chromodynamics. WW production can additionally be a dominant background for measurements of Higgs boson production, and in searches for physics beyond the SM. In contrast to most previous measurements that have focused on WW production in the absence of hadronic jets due to the higher obtainable precision, here a measurement of WW production in association with at least one hadronic jet is presented. This is motivated by an expected improved precision of fully inclusive WW production cross sections in a future combined measurement, and additionally by an enhanced sensitivity to the linear effects of dimension-6 effective field theory operators with respect to the jet veto case. In this measurement, fiducial and differential cross sections are obtained using data collected in sqrt (s) = 13 TeV pp collisions at the ATLAS detector, corresponding to an integrated luminosity of 139 fb-1. Events are selected with exactly one electron and one muon of opposite charge and at least one hadronic jet with a transverse momentum of pT > 30 GeV and a pseudo-rapidity of |eta| < 4.5. Background contributions are estimated using a combination of simulation and data-driven techniques. The dominant background from ttbar events is precisely estimated using a data-driven method that significantly reduces experimental and modeling uncertainties. Differential results are used to place constraints on a dimension-6 effective field theory coefficient.
|Collaboration / Activity||ATLAS|