New insights of multi-particle azimuthal correlations with symmetric cumulants in p-p, p-Pb, and Pb-Pb collisions
The first comparison of anisotropy harmonics (vn, n = 2–4) and event-by-event correlations of different orders between p–p (13 TeV), p–Pb (5.02 and 8.16 TeV) and Pb–Pb (5.02 TeV) as a function of multiplicity is presented. The vn coefficients are extracted via long-range (|Δη|>2) two-particle correlations reaching a very-high-multiplicity region. Event-by-event correlations among v2, v3 and v4 are measured using the four-particle symmetric cumulant (SC(n,m), n = 2, m = 3, 4). For high-multiplicity (more than 100 tracks) events, v2 is found to have a negative correlation with the v3, while the v2 and v4 are positively correlated. Normalized by the two-particle vn, the SC(2,3) are quantitatively similar for p–Pb and Pb–Pb data, while a strong system size dependence is observed for SC(2,4). These new data provide important insights to the origin of collectivity observed in small collision systems.