Abstract
Two-particle azimuthal () and pseudorapidity () correlations using a trigger particle with large transverse momentum () in +Au, Cu+Cu, and Au+Au collisions at 62.4 GeV and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider are presented. The near-side correlation is separated into a jet-like component, narrow in both and , and the ridge, narrow in but broad in . Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated . The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at 200 GeV, is also found in Cu+Cu collisions and in collisions at 62.4 GeV, but is found to be substantially smaller at 62.4 GeV than at 200 GeV for the same average number of participants (). Measurements of the ridge are compared to models.
7 More- Received 26 October 2011
DOI:https://doi.org/10.1103/PhysRevC.85.014903
©2012 American Physical Society