Effect of Wigner energy on the symmetry energy coefficient in nuclei
Effect of Wigner energy on the symmetry energy coefficient in nuclei
复制标题
维格纳能量对原子核对称能系数的影响
DOI：
10.1088/1674-1137/40/9/094101
复制
发表时间：
2016
影响因子：
3.6
通讯作者：
Wang Ning
中科院分区：
文献类型：
--
作者：
Tian Jun-Long;Cui Hai-Tao;Gao Teng;Wang Ning
利用等压核的可用实验结合能差，提取有限核的核对称能系数（包括I - 4项的a - sym(4)系数）。结果表明，随着同位旋不对称性I的增大，提取的对称能系数asym *（a， I）减小，这主要是由Wigner校正引起的，因为e sym*是传统对称能e sym和Wigner能e w的总和，我们得到了最优值J= 30.25±0.10 MeV, a ss= 56.18±1.25 MeV，通过多项式拟合得到20≤a≤261的核的实测结合能，其sym(4)= 8.33±1.21 MeV， Wigner参数x= 2.38±0.12，均方根偏差为23.42 keV。体积对称系数J≤30 MeV对x不敏感，而表面对称系数ass和表面对称系数a(4)在1≤x≤4范围内对x非常敏感。随着同位旋不对称性i的增加，asym(4)项的贡献迅速增加。对于中子非常丰富的原子核，asym(4)项的贡献将发挥重要作用。(作者)
The nuclear symmetry energy coefficient (including the coefficient a sym (4) of the I 4 term) of finite nuclei is extracted by using the differences of available experimental binding energies of isobaric nuclei. It is found that the extracted symmetry energy coefficient a sym*(A, I) decreases with increasing isospin asymmetry I, which is mainly caused by Wigner correction, since e sym* is the summation of the traditional symmetry energy e sym and the Wigner energy e w. We obtain the optimal values J= 30.25±0.10 MeV, a ss= 56.18±1.25 MeV, a sym (4)= 8.33±1.21 MeV and the Wigner parameter x= 2.38±0.12 through a polynomial fit to 2240 measured binding energies for nuclei with 20≤ A≤ 261 with an rms deviation of 23.42 keV. We also find that the volume symmetry coefficient J≃ 30 MeV is insensitive to the value x, whereas the surface symmetry coefficient ass and the coefficient a sym (4) are very sensitive to the value of x in the range 1≤ x≤ 4. The contribution of the a sym (4) term increases rapidly with increasing isospin asymmetry I. For very neutron-rich nuclei, the contribution of the a sym (4) term will play an important role.(authors)