分类: 物理学 >> 核物理学 提交时间: 2023-06-20
摘要: The ratio of the number of emitted pions from the target side to that from the projectile side at target rapiditywithin the reaction plane is investigated for the study of the pion dynamics with an isospin-dependent quantummolecular dynamic model. The results show that high-energy pions are emitted preferentially towards the targetside and, therefore, they are freezed out at the early stage of the collision. By contrast, low-energy pionsare emitted predominantly in the opposite direction, which means that they are emitted in later stage. Thisarguement is based on the shadowing effect caused by the interaction of pions with the spectator matter inperipheral collisions at target or projectile rapidities. This phenomenon disappears in the central collision or atmidrapidity due to the weaker shadowing effect. The calculated ratios are also compared with the experimentaldata.
分类: 物理学 >> 核物理学 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Dynamical dipole mode in heavy-ion collisions has been studied by using an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) model. We investigate the dependence of centroid energy and strength of the spectrum on beam energy, N/Z ratio and mass asymmetry. The calculated yield and angular distribution of the -ray produced by dynamical dipole emission are consistent with the experimental data. The results show that the detailed study of dynamical dipole radiation can provide information on the isospin evolution of charge-asymmetric heavy-ion collisions around the normal nuclear density.