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 thestrongly interacting matter created in heavy-ion collisions. Recently, the results obtained for multi-particle cumulantshave been interpreted as evidence for collectivity in the small collision systems (pp and p–Pb) providing new insightsinto the systems’ fluctuating initial conditions. In this article, first ALICE results on two- and multi-particle cumulantsas a function of charged hadron multiplicity produced at midrapidity (|η| < 1.0) in pp collisions at√s = 13 TeV arereported. The results are compared with measurements in p–Pb collisions at√sNN= 5.02 TeV and in Pb–Pb collisionsat√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 furtherunderstanding of the origin of multi-particle correlations in pp collisions.