Constraints on the percolation model from anomalous centrality evolution of two-particle correlations in Au-Au collisions at sNN=62 and 200 GeV

Abstract

We discuss a possible explanation of the structures observed in two-particle correlations in nucleus-nucleus collisions. An anomalous evolution of two-dimensional two-particle angular correlations with centrality of Au-Au collisions is observed at collision energies sNN=62 and 200 GeV at RHIC at the definite transition points, related to the collision centralities. New structures, elongated in rapidity and localized in azimuth, appear above these critical centralities, which correspond to the same transverse particle density. In this report, we study the observed phenomena using the hypothesis of interacting color flux tubes (strings). We consider the string percolation and string repulsion as the main dynamic origins of the elliptic flow and of the higher harmonics that describe the complicated structures in two-particle correlation topology in Au-Au collisions at RHIC and in Pb-Pb at LHC.