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

Higher-order anisotropic flows v4 and v6 of charged hadrons 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 v2 of identified hadrons in these collisions. We find that the same parton scattering cross section of about 10 mb used in explaining the measured v2 of charged hadrons can also reproduce the recent data on their v4 and v6 from Au+Au collisions at Îs=200A GeV. It is further found that v4 is a more sensitive probe of the initial partonic dynamics in these collisions than v2. Moreover, higher-order parton anisotropic flows are non-negligible and satisfy the scaling relation vn,qspTd,v2,q spTd, 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.