论文标题
旨在建模$^8 $的集群结构与手性互动
Towards modeling cluster structure of $^8$Be with chiral interaction
论文作者
论文摘要
到目前为止，已经研究了核力量在群集状态中的表现，特别是由$α$簇组成的核力量，但尚未阐明。如今，手性有效的野外理论已建立，它将为群集状态的微观理解提供新的启示。我们旨在解决$^8 \ mathrm {Be} $的群集状态中的吸引力来源。也就是说，我们调查了两种二 - 交换相互作用是否充当$α+α$系统的主要吸引力，如先前的工作所预测。我们从理论上描述了$^8 \ mathrm {be} $的群集结构，由边缘模型为此，为此，有效相互作用是根据手性有效场理论得出的现实核力量设计的。手性与局部高斯基碱基相互作用的两体矩阵元素在形成$α$粒子的自旋 - 异种饱和度的近似中配制。在手性相互作用上引入全球式互动，从$^8 \ mathrm {be} $中的地面和低洼的激发态也令人满意地描绘了$α$ - $α$系统的散射相移。发现聚类状态中的吸引力是主要源于两位 - 交换的贡献，以及不可忽略的短期术语。目前的工作可以是构建现实聚类模型的基础，在下一步中将群集状态揭示。
How the nuclear force behaves in cluster states, in particular those consisting of the $α$ clusters, has been investigated so far, but not yet elucidated. Today the chiral effective field theory is established and it would shed new light on the microscopic understanding of the cluster states. We aim to address a possible source of the attraction in the cluster states of $^8\mathrm{Be}$ in view of the pion exchange. Namely, we investigate whether the two-pion-exchange interaction acts as a dominant attraction in the $α+α$ system as predicted by a previous work. We describe theoretically the cluster structure of $^8\mathrm{Be}$ by the Brink model, for which the effective interaction is designed from the realistic nuclear force derived through the chiral effective field theory. The two-body matrix elements of the chiral interaction with the local-Gaussian bases are formulated within the approximation of the spin-isospin saturation forming an $α$ particle. Introducing a global prefactor to the chiral interaction phenomenologically, the ground and low-lying excited states of $^8\mathrm{Be}$, the scattering phase shift of the $α$-$α$ system as well, are satisfactorily depicted. The attraction in the cluster states is found to be stemming from the two-pion-exchange contributions dominantly, along with nonnegligible short-range terms. The present work can be the foundation towards constructing realistic cluster models, by which the cluster states will be revealed microscopically in the next step.
