Effective proton-neutron interaction near the drip line from unbound states in F 25 , 26
Effective proton-neutron interaction near the drip line from unbound states in F 25 , 26
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F 25 , 26 中未结合态滴水线附近的有效质子-中子相互作用
DOI：
10.1103/physrevc.96.054305
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发表时间：
2017
影响因子：
3.1
通讯作者：
Vandebrouck M
中科院分区：
文献类型：
--
作者：
Vandebrouck M
背景：双闭壳层周围的奇-奇核被广泛用于研究质子-中子相互作用。然而，当原子核最终脱离束缚时，这些相互作用作为结合能的函数的演化却鲜为人知。原子核是由一个深束缚的质子和一个在核上的未束缚的中子组成的，特别适合于这个目的。这种质子和中子的耦合产生了多重态，必须确定多重态的能量，以研究连续体的接近度对相应的质子-中子相互作用的影响。束缚态已经确定，只是缺少对它们的明确识别。目的：我们希望通过研究非束缚态的能量和宽度来完成对多重态的研究。该方法首先通过对非束缚态的研究得到验证，在之前的实验中已经观察到共振。方法：在GSI设施的碎片分离器附近产生的放射性光束通过单质子敲除反应在目标上填充非结合态，目标位于/LAND装置的目标焦点上。对发射的射线和中子的探测，加上对原子核动量矢量的重建，使三个非束缚态的能量和两个非束缚态的能量得以确定。结果：根据其宽度和衰变特性，提出了相对能量为49(9)keV的第一个非束缚态是由质子-空穴态产生的。其中，在323(33)keV处的第一个共振被认为是多重体的成员。用独立粒子壳层模型、现象学壳层模型和初始价空间介质相似重整化群方法计算了观测态的能量。结论：与模型相比，推导出的有效质子-中子相互作用减弱了约30-40%，这表明在理论描述中需要实现连续统的作用，或者对原子质量的测定是错误的。
Background:Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. Thenucleus, composed of a deeply boundproton and an unboundneutron on top of ancore, is particularly adapted for this purpose. The coupling of this proton and neutron results in amultiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. Thebound states have been determined, and only a clear identification of theis missing.Purpose:We wish to complete the study of themultiplet in, by studying the energy and width of theunbound state. The method was first validated by the study of unbound states in, for which resonances were already observed in a previous experiment.Method:Radioactive beams ofand, produced at aboutby the fragment separator at the GSI facility were used to populate unbound states inandvia one-proton knockout reactions on atarget, located at the object focal point of the/LAND setup. The detection of emittedrays and neutrons, added to the reconstruction of the momentum vector of thenuclei, allowed the determination of the energy of three unbound states inand two in.Results:Based on its width and decay properties, the first unbound state in, at the relative energy of 49(9) keV, is proposed to be aarising from aproton-hole state. In, the first resonance at 323(33) keV is proposed to be themember of themultiplet. Energies of observed states inhave been compared to calculations using the independent-particle shell model, a phenomenological shell model, and theab initiovalence-space in-medium similarity renormalization group method.Conclusions:The deduced effective proton-neutron interaction is weakened by about 30–40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of.