Flow in small systems in the EPOS4 approach for high-energy scattering

EPOS4 is based on a sophisticated (recently significantly improved) parallel-primary-scattering scenario followed by a hydrodynamic expansion, for all collision systems, from small ones such as proton-proton <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mo>(</a:mo> <a:mi>p</a:mi> <a:mi>p</a:mi> <a:mo>)</a:mo> </a:mrow> </a:math> to large ones such as lead-lead (PbPb). Having already reported on identified particle spectra in recent publications (providing information about radial flow), I discuss here the multiplicity dependence of multiparticle cumulants and flow harmonics, to better understand collectivity in small systems. The model is not particularly tuned for flow results, but it is a “general purpose” approach, trying to accommodate various types of observables with the same model.