Observation of electroweak production of two jets and a Z-boson pair with the ATLAS detector

The observation of electroweak production of two jets in association with a Z‐ boson pair using 139 fb$^{−1}$ of pp collision data at $\sqrt{s}$ = 13 TeV collected by the ATLAS detector at the LHC is reported. Two different final states originating from the decays of the Z boson pair, 4l and 2l2v, are included in the measurements. A significant data excess from the background‐only hypothesis is observed, which corresponds to a statistical significance of 5.5$\sigma$. The observed excess is compatible with the electroweak production of two jets in association with a Z‐boson pair in vector-boson scattering processes. The cross‐sections for inclusive production of ZZ plus two jets, as well as the observed signal strength of the EW production, are presented.