Elliptic flow at collider energies and cascade string models: the role of hard processes and multi-pomeron exchanges

Centrality, rapidity, and transverse momentum dependence of hadron elliptic Row is studied in Au + Au collisions at BNL RHIC energies within the micro scopic quark-gluon string model. The QGSM predictions: coincide well with t he experimental data at roots=130A GeV. Further investigations reveal that multi-pomeron exchanges and hard gluon-gluon scattering in primary collisio ns, accompanied by the rescattering of hadrons in spatially anisotropic sys tem, are the key processes needed for an adequate description of the data. These processes become essentially important fur heavy-ion collisions at fu ll RHIC energy roots = 200A GeV. (C) 2001 Published by Elsevier Science B.V .