Dynamic Theory Simulation Of Pion-meson Production In Au+Au Collision At1A GeV

In this thesis, the Au+Au collisions at1.0A GeV is used to study the pion dynamics by usingthe isospin-dependent quantum molecular dynamics (IQMD) model. There are two parts in thisthesis:First, the transverse momentum of nucleons and pions in the reaction plane as a function ofrapidity have been investigated in heavy ion collisions. The results show that there exists ananticorrelation of the transverse momentum distributions of nucleons and pions in peripheralcollisions, which demonstrate the shadowing effect. While by studying the azimuthal angledistribution of pions with respect to the reaction plane, the shadowing effect appears as anazimuthal anisotropy with a preferential emission of pions perpendicular to the reaction plane. Thedependencies of the nuclear shadowing effect on the impact parameter and the beam energy arealso studied.Second, the ratio of the number of emitted pions from the target side to that from theprojectile side at target rapidity within the reaction plane has been investigated to study the piondynamics. The results show that high-energy pions are emitted preferentially towards the targetside in peripheral collision and, therefore, they are freezed out at the early stage of the collision.By contrast, low-energy pions are emitted predominantly in the opposite direction, which meansthat they are emitted in later stage. This arguement is based on the shadowing effect caused by theinteraction of pions with the spectator matter in peripheral collisions at target or projectilerapidities. This phenomenon disappears in the central collision or at midrapidity due to the weakershadowing effect. In present work, the calculated ratios are also compared with the experimentaldata. The dependence of the ratio on the impact parameter is also studied.