Heavy ion physics at ATLAS and CMS: flow harmonics across systems (pp, p+Pb, Xe+Xe, Pb+Pb)

The collective flow of produced particles is one of the signatures of the creation of the Quark- Gluon Plasma (QGP) in heavy ion collisions. However, similar long-range azimuthal correlations are observed at the LHC energies also in proton-lead and even proton-proton collisions. Extensive and detailed studies of flow harmonics are performed by the ATLAS and the CMS experiments in order to understand mechanisms responsible for these correlations.