本工作采用微观自洽的超越平均场模型研究了原子核²⁰⁸Pb巨偶极共振和巨四极共振到低激发态的 γ 衰变. 采用SkP 参数组很好地再现了巨四极共振到第一个3⁻激发态的实验γ 衰变宽度. 此外, 证明了γ 衰变对于同位旋的强烈依赖性. 最后, 在扣除同位旋效应后, 通过比较巨偶极共振到2₁⁺和巨四极共振到3₁⁻的γ 衰变宽度, 发现巨四极共振波函数中有更大了低激发声子的成分. 由此, 本文展示了γ 衰变是探测原子核共振波函数的有力探针, 也可以用来检验核多体模型的可靠性.

相关论文发表在Physical Review C 103, 064321 (2021)

文章标题: Learning about the structure of giant resonances from their γ decay

文章链接: https://journals.aps.org/prc/pdf/10.1103/PhysRevC.103.064321

摘要:

The direct γ decays of the giant dipole resonance (GDR) and the giant quadrupole resonance (GQR) of ²⁰⁸Pb to low-lying states are investigated by means of a microscopic self-consistent model. The model considers effects beyond the linear response approximation. The experimental γ -decay widths from GQR to the first 3⁻ state and the low-lying dipole states are well reproduced with the Skyrme interaction SkP. The strong sensitivity of γ decay to the isospin of the involved states is proven. By comparing the decay widths between GDR to 2₁⁺ and GQR to 3₁⁻ , a much larger weight of the 3₁⁻ component in the GQR wave function of ²⁰⁸Pb is deduced, with respect to the weight of the 2₁⁺ component in the GDR wave function. Thus, we have shown that γ decay is a unique probe of the resonance wave functions, and a test ground for nuclear structure models.