Measurements of anisotropic flow coefficients (vn) and their cross-correlations using two- and multiparticle cumulant methods are reported in collisions of pp at √s = 13 TeV, p-Pb at a center-of-mass energy per nucleon pair √sNN 1⁄4 5.02 TeV, Xe-Xe at sNN 1⁄4 5.44 TeV, and Pb-Pb at √sNN = 5.02 TeV recorded with the ALICE detector. The multiplicity dependence of vn is studied in a very wide range from 20 to 3000 particles produced in the midrapidity region jηj < 0.8 for the transverse momentum range 0.2 < pT < 3.0 GeV=c. An ordering of the coefficients v2 > v3 > v4 is found in pp and p-Pb collisions, similar to that seen in large collision systems, while a weak v2 multiplicity dependence is observed relative to nucleus-nucleus collisions in the same multiplicity range. Using a novel subevent method, v2 measured with four-particle cumulants is found to be compatible with that from six-particle cumulants in pp and p-Pb collisions. The magnitude of the correlation between v2n and v2m, evaluated with the symmetric cumulants SCðm; nÞ is observed to be positive at all multiplicities for v2 and v4, while for v2 and v3 it is negative and changes sign for multiplicities below 100, which may indicate a different vn fluctuation pattern in this multiplicity range. The observed long-range multiparticle azimuthal correlations in high multiplicity pp and p-Pb collisions can neither be described by PYTHIA 8 nor by impact-parameter- Glasma, MUSIC, and ultrarelativistic quantum molecular dynamics model calculations, and hence, provide new insights into the understanding of collective effects in small collision systems.
