Isoscalar monopole and dipole transitions in Mg 24 , Mg 26 , and Si 28
Isoscalar monopole and dipole transitions in Mg 24 , Mg 26 , and Si 28
复制标题
Mg 24 、Mg 26 和 Si 28 中的等标量单极子和偶极子跃迁
DOI：
10.1103/physrevc.103.044315
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发表时间：
2021
影响因子：
3.1
通讯作者：
Adsley P
中科院分区：
文献类型：
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作者：
Adsley P
背景：黑洞中的原子核表现出明显的团簇现象和平均场现象的相互作用。原子核，如AND，在过去一直是这两种现象理论研究的焦点。预测了这些原子核中各种不同的团簇结构，其特征是等标偶极和单极跃迁。例如，在中预测了低能量的等标量涡偶极态。团簇和涡旋平均场现象可以通过激发等标量粒子的单极态和偶极态来探测。目的：我们从实验和理论上研究了三个本质不同、性质不同的轻核：硬扁核、软扁核和软扁核中的等标偶极子和单极子强度。方法：在南非开普敦iThemba实验室的K600磁谱仪上对非弹性散射粒子进行动量分析。在放置在K600焦平面的两个多丝漂移室和两个塑料闪烁体中探测到了散射粒子。在理论讨论中，使用了Skyrme准粒子随机位相近似(QRPA)和反对称分子动力学产生器坐标方法()。结果：在所研究的原子核中观察到了许多等标量单极和偶极跃迁。利用这一信息，对各种激发态进行了结构指认，并与实验数据进行了比较。QRPA计算得出结论：(I)平均场涡度主要出现在偶极态中，(Ii)偶(单)极态应具有强烈的形变诱导八极(四极)混合物，以及(Iii)在粒子阈值附近，对于长形核和扁形核，应该存在一个集合态，具有令人印象深刻的八极强度。计算结果表明，某些观测状态可能具有混合(平均场)特征或对应于特定的星团构型。结论：初步建立了qRPA和理论状态之间的对应关系。QRPA和分析表明，低能等标偶极态结合了团簇和平均场的性质。QRPA计算表明，低能涡度在局域化、碎片化和非局域化三个方面都有很好的分布。
Background:Nuclei in theshell demonstrate a remarkable interplay of cluster and mean-field phenomena. Thenuclei, such asand, have been the focus of the theoretical study of both phenomena in the past. A variety of different cluster structures in these nuclei are predicted, characterized by isoscalar dipole and monopole transitions. For example, low-energy isoscalar vortical dipole states were predicted in. The cluster and vortical mean-field phenomena can be probed by excitation of isoscalar monopole and dipole states in scattering of isoscalar particles such as deuterons orparticles.Purpose:We investigate, both experimentally and theoretically, the isoscalar dipoleand monopolestrengths in three essentially different light nuclei with different properties: stiff prolate, soft prolate, and soft oblate. We analyze possible manifestations of clustering and vorticity in these nuclei.Methods:Inelastically scatteredparticles were momentum analyzed in the K600 magnetic spectrometer at iThemba LABS, Cape Town, South Africa. The scattered particles were detected in two multiwire drift chambers and two plastic scintillators placed at the focal plane of the K600. In the theoretical discussion, the Skyrme quasiparticle random-phase approximation (QRPA) and antisymmetrized molecular dynamicsgenerator coordinate method () were used.Results:A number of isoscalar monopole and dipole transitions were observed in the nuclei studied. Using this information, suggested structural assignments have been made for the various excited states.andstrengths obtained within QRPA andare compared with the experimental data. The QRPA calculations lead us to conclude that (i) the mean-field vorticity appears mainly in dipole states with, (ii) the dipole (monopole) states should have strong deformation-induced octupole (quadrupole) admixtures, and (iii) near the-particle threshold there should exist a collective state withfor prolate nuclei andfor oblate nuclei, with an impressive octupole strength. The results of thecalculations suggest that some observed states may have a mixed (mean-fieldcluster) character or correspond to particular cluster configurations.Conclusion:A tentative correspondence between observed states and theoretical states from QRPA andwas established. The QRPA andanalysis shows that low-energy isoscalar dipole states combine cluster and mean-field properties. The QRPA calculations show that the low-energy vorticity is well localized in, fragmented in, and absent in.