Energy dependence of directed flow in Au+Au collisions from a multiphase transport model

摘要

The directed flow of charged hadron and identified particles has been studied in the framework of a multiphase transport (AMPT) model for 197Au+197Au collisions at √sNN=200,130,62.4,39,17.2, and 9.2 GeV. The rapidity, centrality, and energy dependence of directed flow for charged particles over a wide rapidity range are presented. The AMPT model gives the correct v1(y) slope, as well as its trend as a function of energy, while it underestimates the magnitude. Within the AMPT model, the proton v1 slope is found to change its sign when the energy increases to 130 GeV—a feature that is consistent with “anti-flow.” Hadronic rescattering is found to have little effect on v1 at top energies currently available at the BNL Relativistic Heavy Ion Collider (RHIC). These studies can help us to understand the collective dynamics early on in relativistic heavy-ion collisions, and they can also be served as references for the RHIC Beam Energy Scan Program.