Observation of Electroweak Production of a Same-Sign W Boson Pair in Association with Two Jets in pp Collisions at √s = 13 TeV with the ATLAS Detector

Abstract

This Letter presents the observation and measurement of electroweak production of a same-sign W boson pair in association with two jets using 36.1 fb−1 of proton-proton collision data recorded at a center-of-mass energy of √s=13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of 69 ± 7 events, corresponding to an observed signal significance of 6.5 standard deviations. The measured fiducial signal cross section is σ^fid = 2.89 +0.51 −0.48 (stat) +0.29 −0.28 (syst) fb.