Spin-isospin transitions in nuclei away from the valley of stability are essential for the description of astrophysically relevant weak interaction processes. While they remain mainly beyond the reach of experiment, theoretical modeling provides important insight into their properties. In order to describe the spin-isospin response, the proton-neutron relativistic quasiparticle random phase approximation is formulated using the relativistic density-dependent point coupling interaction, and separable pairing interaction in both the $T=1$ and $T=0$ pairing channels. By implementing recently established DD-PCX interaction with improved isovector properties relevant for the description of nuclei with neutron-to-proton number asymmetry, the isobaric analog resonances (IAR) and Gamow-Teller resonances (GTR) have been investigated. In contrast to other models that usually underestimate the IAR excitation energies in Sn isotope chain, the present model accurately reproduces the experimental data, while the GTR properties depend on the isoscalar pairing interaction strength. This framework provides not only an improved description of the spin-isospin response in nuclei, but it also allows future large-scale calculations of charge-exchange excitations and weak interaction processes in stellar environment.

中文翻译：

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基于相对论密度依赖点耦合模型的核电荷交换激发

远离稳定谷的原子核中的自旋-同位旋跃迁对于描述与天体物理学相关的弱相互作用过程至关重要。虽然它们主要超出了实验的范围，但理论建模提供了对其特性的重要洞察。为了描述自旋 - 同位旋响应，质子 - 中子相对论准粒子随机相位近似是使用相对论密度依赖点耦合相互作用和可分离配对相互作用来制定的$吨=1$ 和 $吨=0$配对通道。通过实施最近建立的 DD-PCX 相互作用，改进与描述具有中子到质子数不对称的原子核相关的等向量特性，对等压模拟共振 (IAR) 和 Gamow-Teller 共振 (GTR) 进行了研究。与通常低估 Sn 同位素链中 IAR 激发能的其他模型相比，本模型准确地再现了实验数据，而 GTR 特性取决于等标配对相互作用强度。该框架不仅提供了对原子核中自旋-同位旋响应的改进描述，而且还允许未来对恒星环境中的电荷交换激发和弱相互作用过程进行大规模计算。