论文标题
超越均值对对称能量及其斜率的影响来自$^{68} $ ni的低洼偶极响应
Beyond-mean-field effects on the symmetry energy and its slope from the low-lying dipole response of $^{68}$Ni
论文作者
论文摘要
我们研究了基于天际相互作用的不稳定核中低能偶极激发$^{68} $ ni，其中超出均值（BMF）减去了第二个随机相位及相关（SSRPA）模型。首先，将强度分布与可用的实验数据进行了比较，并分析了某些选定峰的过渡密度。通过研究此类激发的等值级/等异卵形特征，还讨论了所谓的同胞分裂。 然后，我们以间接的方式估算BMF对无限物质的对称能量以及其斜率从BMF SSRPA低洼强度分布开始的估计。为此，使用了几种线性相关性，第一个相关是与总能量加权规则（EWSR）和对称能量的斜率之间存在的贡献（与低能强度相关的）之间存在的相关性。可以以这种方式提取对称能的斜率的BMF估计值。 $^{68} $ ni的这种斜率与中子皮的厚度与中子皮肤厚度$^{68} $ ni与电偶极极化时间之间的相关性之间的相关性之间的相关性，然后使用对称能量来对对称能量产生BMF的影响。
We study low-energy dipole excitations in the unstable nucleus $^{68}$Ni with the beyond-mean-field (BMF) subtracted second random-phase-approximation (SSRPA) model based on Skyrme interactions. First, strength distributions are compared with available experimental data and transition densities of some selected peaks are analyzed. The so-called isospin splitting is also discussed by studying the isoscalar/isovector character of such excitations. We estimate then in an indirect way BMF effects on the symmetry energy of infinite matter and on its slope starting from the BMF SSRPA low-lying strength distribution. For this, several linear correlations are used, the first one being a correlation existing between the contribution (associated with the low-energy strength) to the total energy-weighted sum rule (EWSR) and the slope of the symmetry energy. BMF estimates for the slope of the symmetry energy can be extracted in this way. Correlations between such a slope and the neutron-skin thickness of $^{68}$Ni and correlations between the neutron-skin thickness of $^{68}$Ni and the electric dipole polarizability times the symmetry energy are then used to deduce BMF effects on the symmetry energy.
