文章基本信息

标题：Impact Parameter Dependence of Ratio in Probing the Nuclear Symmetry Energy Using Heavy-Ion Collisions
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作者：Gao-Feng Wei ; Guo-Qiang He ; Xin-Wei Cao 等
期刊名称：Advances in High Energy Physics
印刷版ISSN：1687-7357
电子版ISSN：1687-7365
出版年度：2016
卷号：2016
DOI：10.1155/2016/9317873
出版社：Hindawi Publishing Corporation
摘要：The impact parameter dependence of ratio is examined in heavy-ion collisions at 400 MeV/nucleon within a transport model. It is shown that the sensitivity of ratio on symmetry energy shows a transition from central to peripheral collisions; that is, the stiffer symmetry energy leads to a larger ratio in peripheral collisions while the softer symmetry energy always leads this ratio to be larger in central collisions. After checking the kinematic energy distribution of ratio, we found this transition of sensitivity of ratio to symmetry energy is mainly from less energetic pions; that is, the softer symmetry energy gets the less energetic pions to form a smaller ratio in peripheral collisions while these pions generate a larger ratio in central collisions. Undoubtedly, the softer symmetry energy can also lead more energetic pions to form a larger ratio in peripheral collisions. Nevertheless, considering that most of pions are insufficiently energetic at this beam energy, we therefore suggest the ratio as a probe of the high-density symmetry energy effective only in central at most to midcentral collisions, thereby avoiding the possible information of low-density symmetry energy carried in ratio from peripheral collisions.