Rapidity and system size dependence of anisotropic flows in relativistic heavy ion collisions

The azimuthal anisotropy of hadron transverse momentum distributions in heavy ion collisions at RHIC is sensitive to the properties of produced matter. In the framework of transport approach, it was shown in Ref.[ 1] using the ZPC model [ 2] that the value of the second harmonic, i.e., the elliptic flow, depends sensitively on the magnitude of parton scattering cross sections. With a more realistic collision dynamics via the AMPT model [ 3, 4], it was further shown that the observed large elliptic flow and its ordering according to hadron masses [ 5] as well as high-order anisotropic flows [ 6] could be explained if partons scatter with cross sections much larger than those given by the perturbative QCD. Including also charm quarks in the AMPT model [ 7], the observed large elliptic flow of electrons from the decay of charmed mesons is again consistent with a large charm scattering cross section. In the present contribution, recent results from the AMPT model on the rapidity and collision system dependence of anisotropic flows are presented [ 8, 9, 10].