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arXiv 1301.3256nucl-thastro-ph.SRnucl-ex
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从中子-核散射数据中提取核对称势和能量

Extracting the nuclear symmetry potential and energy from neutron-nucleus scattering data

Xiao-Hua Li, Bao-Jun Cai, Lie-Wen Chen, Rong Chen, Bao-An Li, Chang Xu

备注：
7 pages, 4 figures, 2 tables. Discussions and 1 table added. Accepted version to appear in PLB
发表信息：
Phys.Lett.B721:101-106,2013
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摘要：

根据Hugenholtz-Van Hove定理，非对称核物质中的对称能及其密度斜率可以用单个核子势唯一地分解，在正常密度下，单个核子势可以由分析核子-核散射数据得到的核子光学模型势约束.为了更准确地从中子-核散射数据中提取对称能及其在正常密度下的密度斜率的信息，超越了众所周知的Lane势，我们在光学模型势和对称能分解中一致地包括了同位旋不对称的二阶项。我们发现，在非对称核物质中，二阶对称势$U_{sym,2}$的强度与一阶对称势U_{sym,1} $, especially at high nucleon momentum. While the $ U_{sym,1} $ at normal density decreases with nucleon momentum, the $ U_{sym,2} $ is found to have the opposite behavior. Moreover, we discuss effects of the $ U_{sym,1} $ and $ U_{sym,2} $ on determining the density dependence of the symmetry energy, and we find that the available neutron-nucleus scattering data favor a softer density dependence of the symmetry energy at normal density with a negligible contribution from the $ U_{sym,2} $相比是显著的.

英文摘要：

According to the Hugenholtz-Van Hove theorem, the symmetry energy and its density slope can be decomposed uniquely in terms of the single-nucleon potential in asymmetric nuclear matter which, at normal density, can be constrained by the nucleon optical model potential extracted from analyzing the nucleon-nucleus scattering data. To more accurately extract information on the symmetry energy and its density slope at normal density from neutron-nucleus scattering data, going beyond the well-known Lane potential, we include consistently the second order terms in isospin asymmetry in both the optical model potential and the symmetry energy decomposition. We find that the strength of the second-order symmetry potential $U_{sym,2}$ in asymmetric nuclear matter is significant compared to the first-order one U_{sym,1}$, especially at high nucleon momentum. While the $U_{sym,1}$ at normal density decreases with nucleon momentum, the $U_{sym,2}$ is found to have the opposite behavior. Moreover, we discuss effects of the $U_{sym,1}$ and $U_{sym,2}$ on determining the density dependence of the symmetry energy, and we find that the available neutron-nucleus scattering data favor a softer density dependence of the symmetry energy at normal density with a negligible contribution from the $U_{sym,2}$.

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