Probing the quark-gluon phase transition using energy and system-size dependence of long-range multiplicity correlations in heavy ion collisions from the STAR experiment

Abstract

Long-range forward-backward multiplicity correlations have been measured in heavy ion collisions at RHIC. Results for short and long-range multiplicity correlations (forward-backward) are presented for several systems (Au+Au, Cu+Cu, and pp) and energies (e.g. \(\sqrt {s_{NN} } \) = 200 and 62.4 GeV). A strong, long-range correlation is seen for central heavy ion collisions at \(\sqrt {s_{NN} } \) = 200 GeV that vanishes in semi-peripheral events and pp collisions. There is no apparent scaling with the number of participants (N part) involved in the collision. These correlations provide information about the longitudinal behavior of the system formed in heavy ion collisions. To access the transverse behavior, the clusters produced in the same heavy ion collisions have been characterized by a study of the energy and system size dependence of the percolation density parameter (ρ). The relationship between the long-range correlation and percolation has been explored to characterize the hadron-quark/gluon phase transition and rapid thermalization of the system.