Observation of $WZ\gamma$ Production in $pp$ Collisions at $\sqrt{s}=13$ TeV with the ATLAS Detector

ATLAS Collaboration

This Letter reports the observation of $WZ\gamma$ production and a measurement of its cross-section using 140.1 $\pm$ 1.2 fb${}^{-1}$ of proton-proton collision data recorded at a center-…