Evolution of the N=20 and 28 shell gaps and two-particle-two-hole states in the FSU interaction
Evolution of the N=20 and 28 shell gaps and two-particle-two-hole states in the FSU interaction
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FSU 相互作用中 N=20 和 28 壳间隙和两粒子两孔态的演化
DOI：
10.1103/physrevresearch.2.043342
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发表时间：
2020
影响因子：
4.2
通讯作者：
Volya, A.
中科院分区：
文献类型：
--
作者：
Lubna, R. S.;Kravvaris, K.;Tabor, S. L.;Tripathi, Vandana;Rubino, E.;Volya, A.
核子-核子基本力与原子核多体结构之间的联系是现代核物理的一个主要问题。平均场的演化、传统壳层结构的反演以及具有极端质子-中子比的原子核中的高自旋态结构是最近许多实验研究的中心，这些实验研究的目标是导致这些现象的有效核哈密顿量的矩阵元。壳层模型的FSU跨壳层相互作用被成功地拟合到壳核的大范围的负宇称态。在本文中，我们探讨了核结构的演变和周围的反转岛（IoI），其中低洼国家涉及跨壳层粒子-空穴激发。我们应用FSU相互作用系统地追踪了形成28壳层能隙和28壳层能隙的轨道的有效单粒子能量的相对位置。我们发现，以上的质子数约13，theneutron轨道低于，这被认为是正常的顺序，但系统地，对于更奇特的核与lower和10的轨道顺序颠倒。中子轨道的交叉正好发生在中子分离阈值附近。我们的哈密顿量再现非常好的绝对结合能范围广泛的核和反转的配置内的IoI的核。有效相互作用很好地解释了核子对穿过壳层能隙时的能量和随质量数的变化。本文提出了一个经验确定的有效哈密顿量，从许多最近的实验数据，使我们能够显着提高我们的知识跨壳层核相互作用矩阵元。这个哈密顿量描述了两个粒子，两个孔的跨壳层激发，结合能和物理的对齐状态，不是一个适合的一部分，是显着的质量，使FSU相互作用的一个重要工具，为未来的探索奇异核。
The connection between fundamental nucleon-nucleon forces and the observed many-body structure of nuclei is a main question of modern nuclear physics. Evolution of the mean field, inversion of traditional shell structures, and structure of high spin states in nuclei with extreme proton-to-neutron ratios are at the center of numerous recent experimental investigations targeting the matrix elements of the effective nuclear Hamiltonian that is responsible for these phenomena. The FSUcross-shell interaction for the shell model was successfully fitted to a wide range of mostly intruder negative parity states of theshell nuclei. In this paper, we explore the evolution of nuclear structure in and around the island of inversion (IoI), where low-lying states involve cross-shell particle-hole excitations. We apply the FSU interaction to systematically trace out the relative positions of the effective single-particle energies of theandorbitals forming theand 28 shell gaps. We find that above a proton number of about 13, theneutron orbital lies below that of, which is considered normal ordering but, systematically, for more exotic nuclei with lowerand 10 the order of orbitals reversed. The crossing of the neutron orbitals happens right near the neutron separation threshold. Our Hamiltonian reproduces remarkably well the absolute binding energies for a broad range of nuclei and the inversion in the configurations of nuclei inside the IoI. The effective interaction accounts well for the energies and variations with mass numberof aligned high-spin states that involve nucleon pairs prompted across the shell gap. This paper puts forward an empirically determined effective Hamiltonian where data from many recent experiments allowed us to significantly improve our knowledge about cross-shell nuclear interaction matrix elements. The quality with which this Hamiltonian describes the two-particle, two-hole cross-shell excitations, binding energies, and the physics of aligned states that were not a part of the fit, is remarkable, making the FSU interaction an important tool for the future exploration of exotic nuclei.