Partonic effects on higher-order anisotropic flows in relativistic heavy-ion collisions

Abstract

Higher-order anisotropic flows $v_4$ and $v_6$ in heavy ion collisions at the Relativistic Heavy Ion Collider are studied in a multiphase transport model that has previously been used successfully for describing the elliptic flow $v_2$ in these collisions. We find that the same parton scattering cross section of about 10 \textrm{mb} used in explaining the measured $v_2$ can also reproduce the recent data on $v_4$ and $v_6$ from Au + Au collisions at $\sqrt{s}=200$ \textrm{AGeV}. It is further found that the is a more sensitive probe of the initial partonic dynamics in these collisions than $v_2$. Moreover, higher-order parton anisotropic flows are nonnegligible and satisfy the scaling relation $v_{n,q}(p_T)\sim v_{2,q}^{n/2}(p_T)$, which leads naturally to the observed similar scaling relation among hadron anisotropic flows when the coalescence model is used to describe hadron production from the partonic matter.

5 pages, 3 figures, version to appear in PRC as a Rapid Communication