| Experiments in high energy heavy-ion collisions can produce very density andhot nuclear matter, because people can obtain the information of the final stateparticles in the heavy ion collision experiments, but we cannot gain the properties ofnuclear matter by means of detecting the initial state directly. People need to use theinformation of the final state to speculate that nuclear material dynamic evolutionprocess in the strong interaction region indirectly. Research shows that the asymmetryof the initial coordinate space will be transformed into a asymmetry at the end of themomentum space through the dynamic evolution, so the collective flow—carry a lotof the initial moment and information of dynamic evolution at final state observable,became one of the focus of heary-ion collisions.To the initial state, people usually use eccentricity to describe space coordinatesasymmetry of the nuclear matter. And for different definition method, the numerical isdifferent, too.This paper summarizes the calculation method of eccentricity in reactionplane and participant’s, and analyzes the changing with the collision parameters forthe system.In RHIC energy region, due to the high collision energy, the evolution of thesystem is mainly affected by the strong interaction between nuclear.AMPT(AMulti-Phase Transport Model，AMPT) model including parton phase and hadronicphase, so it can describe the elliptical flow in RHIC well.In this article,using stringmelting AMPT model to simulate Au+Au collision at RHIC (Relativistic Heavy IonCollider,RHIC) energies (62.4GeV,130GeV and200GeV), and calculated integraland differential elliptic of the final state particles and the relationship with rapidity,psedorapidity, transverse momentum, scattering cross section of parton and the impactparameter, analyzing the effect of the asymmetry in initial space to elliptic flow. |
