文摘
The time evolution of both proton and anti-proton v 2 flows from Au+Au collisions at \(\sqrt {{S_{NN}}} = 7.7\) GeV are examined by using both pure cascade and mean-field potential versions of the UrQMD model. Due to a stronger repulsion at the early stage introduced by the repulsive potentials and hence much less annihilation probabilities, anti-protons are frozen out earlier with smaller v 2 values. Therefore, the experimental data of anti-proton v 2 as well as the flow difference between proton and anti-proton can be reasonably described with the potential version of UrQMD. Keywords elliptic flow difference UrQMD mean field potential annihilation process