Spectra of Halo Nuclei

Based on the self-similar-structure shell model a size resonance model, which includes the size resonance of halo neutron orbit and the correlation size resonance of core surface, is proposed. In terms of the size resonance model the excited spectra and the soft dipole resonances for ¹¹Be and ¹¹li are reproduced.     

Long-Range Effective Potential in Halo Nuclei

A way to derive the long range effective potential and the corresponding eigenequation for halo nuclei¹¹ Ll, ¹⁴Be and ¹⁷B is presented by using the equivalent two body method for a three body system. The results agree with both Efimov' s conclusions and experimental data for halo nuclei.     

Efimov Effect in 2-Neutron Halo Nuclei

We provide a brief overview of our theoretical investigations, carried out in recent years, to study Efimov effect in 2-n halo nuclei. The calculations provide the evidence for the occurrence of at least two Efimov states in ²⁰C. These states disappear one by one as the two-body binding energy is increased and show up as asymmetric resonances in the elastic scattering cross section of n–¹⁹C system. The asymmetric nature of the resonances is explained by invoking the mechanism of Fano resonance.     

Electroweak Interaction in Lightest Nuclei and Extraction of the Induced Pseudoscalar Constant

We review the present state of our knowledge of the induced pseudoscalar constant g_P, based on the analysis of the electroweak reactions in the lightest nuclei.     

晕核和推广的Glauber理论

简要介绍了中子晕和质子晕研究的最新实验进展,同时,讨论了近年来发展的同位旋,能量有关的具有晕核结构的Glauber理论及它在描述晕核与核散射时的重要性.The development of new experiments for neutron (or proton) halo is briefly described, while the isospin and energy dependence of Glauber theory and its importance in describing halo nuclei-nucleus scattering are discussed.     

Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy.The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite digerent mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections, induced by the halo nuclei due to the very weak binding and the very extended density distribution.     

Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable. nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy. The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.     

Halo Nuclei: Stepping Stones Across the Dripline

The availability of intense secondary beams in conjunction with efficient detection setups allows for a production and study of the most extreme nuclear systems, in terms of asymmetry of proton and neutron number, in the continuum. They can be produced via transfer and knockout reactions, depending on beam energies, with beams of nuclei close to the driplines, exhibiting exotic properties themselves, as seeds. These nuclear open quantum systems far from the valley of beta stability challenge nuclear structure theory being as well as reaction theory that tries to describe their production mechanisms. Due to their strong clustering they exhibit a rather clean few-body character. From experiments momentum distributions, relative energy spectra, and spin alignment during the reaction can be determined, which leads to the observation of energy and angular correlations as well as dependent quantities like e.g. the profile function denoting a momentum width in dependence of relative energy. They are determined from momentum vectors of fragments and gamma radiation leaving the reaction zone. The link to intrinsic properties of these unbound systems has to be explored by gathering precise knowledge of the properties of the seed nuclei and compare them to the structures observed in the continuum. In this paper I will exemplify the above-mentioned methods, and apply them particularly to light systems like ¹⁰He, ^10?13Li, and neutron-rich Beryllium systems. Furthermore, perspectives for the ⁷H and heavy Oxygen systems are discussed.     

奇奇核与奇A核n-p相互作用

从结合能实验值提取n-p相互作用能ε_ip-jn,系统比较了奇奇核单质子单中子相互作用能ε_1p-1n与相邻奇A核相应量的平均值,发现前者普遍大于后者.提出奇奇核n-p增强的解释为,GMshift效应和同类核子对关联对奇A核n-p相互作用的削弱效应.同时指出,奇质子核的ε_1p-2n相当好地近似等于同质量数奇中子核的ε_2p-1n,并且这与Garvey-Kelson关系是等价的.     

轻核中中子间的对相互作用和中子晕

选择Skyme势E作为两核子间唯象相互作用,在Hartree-Fock理论中结合粒子数守恒方法处理同类核子间的对相互作用,计算了Li和Be的丰中子同位素的结构,计算表明中子间的对相互作用和双中子晕之间存在紧密的联系.     

Relativistic Mean Field Study on Halo Structures of Mirror Nuclei

Halo structures of some light mirror nuclei are investigated with the relativistic mean field （RMF） theory. The calculations show that the dispersion of the valence proton is larger than that of the valence neutron in its mirror nucleus, the difference between the root-mean-square （rms） radius of the valence nucleon in each pair of mirror nuclei becomes smaller with the increase of the mass number A, and all the ratios of the rms radius of the valence nucleon to that of the matter in each pair of mirror nuclei decrease almost linearly with the increase of the mass number A.     

晕核及弱束缚核的近垒熔合

阐述了晕核近垒熔合反应研究的意义;叙述了理论上关于晕核破裂与入射道相对运动的耦合使熔合截面增强还是阻禁了晕核熔合两种相反观点的争论,以及晕核熔合反应实验研究的现状;探讨了用弱束缚核代替晕核进行实验研究以求对理论上的争论作出判断的构想．     

复动量表象方法对奇特核中晕现象的研究

晕现象的研究使人们对核结构有了新的认识。连续谱,尤其是连续谱中的共振态在其中扮演着重要角色。复动量表象(CMR)方法不仅能够统一描述束缚态、共振态和连续谱,而且能够很好地描述窄共振和宽共振。本文介绍了CMR方法对原子核共振态的研究。给出了31Ne和19C等核的束缚态和共振态的单粒子能量随形变参数β₂的变化规律,分析了19C和31Ne中单中子晕形成的物理机制和在中子数N=20附近能级反转的原因,并预测了比37Mg重的核中的单中子晕现象,这一预测结果对在实验中寻找较重的晕核具有一定的参考价值。这些研究表明CMR 方法不仅适用于描述稳定核,也适用于描述具有弥散物质分布的奇特核。     

晕核反应总截面和密度分布

利用考虑了量子修正、库仑修正、核子–核子碰撞同位旋效应和假定有效原子核密度分布后得到的改进的Glauber理论,计算了晕核与稳定核反应总截面,研究了晕核结构对反应总截面的影响.结果发现对于¹¹Be,¹⁴Be和¹¹Li等入射核,必须考虑它们的晕核结构和利用自由的核子–核子碰撞截面才能得到与实验符合的反应截面,并可依据反应总截面来确定晕核的密度分布和均方半径等信息.     

New Anomaly of the Axial-Vector Current

By computing the axial-vector current operator equation, we find the anomalous axial-vector curl equation besides the well-known anomalous axial-vector divergence equation (the Adler-Bell-Jackiw anomaly) and discuss its implication.     

Momentum Distribution of a Fragment and Nucleon Removal Cross Section in the Reaction of Halo Nuclei

Recently the research on the halo structure of drip-line nuclei has shown some interesting properties of the existence of one or more halo nucleons. In the framework of few-body Glauber model, the momentum distribution of a fragment and nucleon removal cross section in the reaction of halo nuclei is presented and extended to nuclei having more than one halo nucleons. The reaction mechanism is treated with and without taking account of the final-state interaction. The wave function of removal halo nucleons in the continuum state is modified by imposing an orthogonal condition to the bound state. An analytical expression of the longitudinal momentum distribution of the fragment is derived when the bound state wave function of halo nucleons is taken as a Gaussian-type function. This is useful in the further investigation on the structure of halo nuclei.