Investigations of anisotropic collectivity using multi-particle correlations in pp, p-Pb and Pb-Pb collisions

Abstract

Two- and multi-particle azimuthal correlations have proven to be an excellent tool to probe the properties of the strongly interacting matter created in heavy-ion collisions. Recently, the results obtained for multi-particle cumulants have been interpreted as evidence for collectivity in the small collision systems (pp and p–Pb) providing new insights into the systems' fluctuating initial conditions. In this article, first ALICE results on two- and multi-particle cumulants as a function of charged hadron multiplicity produced at midrapidity (| η | < 1.0) in pp collisions at s=13 TeV are reported. The results are compared with measurements in p–Pb collisions at sNN=5.02 TeV and in Pb–Pb collisions at sNN=2.76 TeV . A new method for the 4-particle cumulant with an η gap denoted as cn{4,|Δη|} will be presented, which is capable of further suppressing non-flow effects in multi-particle cumulants. The results allow for further understanding of the origin of multi-particle correlations in pp collisions.