Electromagnetic structure of A=2 and 3 nuclei and the nuclear current operator
Electromagnetic structure of A=2 and 3 nuclei and the nuclear current operator
复制标题
A=2和3核的电磁结构及核电流算符
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
S. Rosati
中科院分区：
文献类型：
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作者：
L. Marcucci;M. Viviani;R. Schiavilla;R. Schiavilla;A. Kievsky;S. Rosati
从两个和三个核子的相互作用，使用介子交换机制或最小的替代，这些相互作用的动量依赖性的守恒的两体和三体电磁流的不同模型构建。阐明了这两种不同方案之间的联系。计算了一些低能的电子能谱观测量，包括（i）热中子能量下的np辐射俘获和低能下的氘核光致衰变，（ii）nd和pd辐射俘获反应，（iii）{sup 3}H和{sup 3}He的等密度和等矢量磁形状因子，对这些模型的电流算符进行了比较研究.以现实的阿贡v{sub 18}双核子和厄巴纳IX或图森-墨尔本三核子相互作用为例进行了研究。对于A=3的过程，用关联超球谐函数方法得到了氘破裂阈值以下和以上的束缚波函数和连续波函数。三体电流对热中子能量下的{sup 2}H（p，{gamma}）{sup 3}He过程和{sup 2}H（n，{gamma}）{sup 3}H截面中的一些极化观测值有很小但重要的贡献。它表明，电流的使用，不完全满足电流守恒与两个和三个核子相互作用的哈密顿量是负责的一些discanciesmore »报告在以前的研究中的实验和理论偏振观测值之间的pd辐射捕获。«少
Different models for conserved two- and three-body electromagnetic currents are constructed from two- and three-nucleon interactions, using either meson-exchange mechanisms or minimal substitution in the momentum dependence of these interactions. The connection between these two different schemes is elucidated. A number of low-energy electronuclear observables, including (i) np radiative capture at thermal neutron energies and deuteron photodisintegration at low energies, (ii) nd and pd radiative capture reactions, and (iii) isoscalar and isovector magnetic form factors of {sup 3}H and {sup 3}He, are calculated to make a comparative study of these models for the current operator. The realistic Argonne v{sub 18} two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions are taken as a case study. For A=3 processes, the bound and continuum wave functions, both below and above deuteron breakup threshold, are obtained with the correlated hyperspherical harmonics method. Three-body currents give small but significant contributions to some of the polarization observables in the {sup 2}H(p,{gamma}){sup 3}He process and the {sup 2}H(n,{gamma}){sup 3}H cross section at thermal neutron energies. It is shown that the use of a current that did not exactly satisfy current conservation with the two- and three-nucleon interactions in the Hamiltonian was responsible for some of the discrepanciesmore » reported in previous studies between the experimental and theoretical polarization observables in pd radiative capture.« less