Influence of the Coulomb exchange term on nuclear single-proton resonances  

作　　者：Shu-Yang Wang Zhong-Lai Zhu Zhong-Ming Niu 

机构地区：[1]School of Physics and Materials Science, Anhui University

出　　处：《Nuclear Science and Techniques》2016年第5期231-237,共7页核技术（英文）

基　　金：partly supported by the National Natural Science Foundation of China(No.11205004);the Key Research Foundation of Education Ministry of Anhui Province of China(No.KJ2016A026)

摘　　要：Nuclear single-proton resonances are sensitive to the Coulomb field,while the exchange term of Coulomb field is usually neglected due to its nonlocality.By combining the complex scaling method with the relativistic mean-field model,the influence of the Coulomb exchange term on the single-proton resonances is investigated by taking Sn isotopes and N=82 isotones as examples.It is found that the Coulomb exchange term reduces the singleproton resonance energy within the range of 0.4-0.6 MeV and leads to similar isotopic and isotonic trends of the resonance energy as those without the Coulomb exchange term.Moreover,the single-proton resonance width is also reduced by the Coulomb exchange term,whose influence generally decreases with the increasing neutron number and increases with the increasing proton number.However,the influence of the Coulomb exchange term cannot change the trend of the resonance width with respect to the neutron number and proton number.Furthermore,the influence of the Coulomb exchange term on the resonance width is investigated for the doubly magic nuclei ^(40)Ca,^(56,78)Ni,^(100,132)Sn,and ^(208)Pb.It is found that the Coulomb exchange term reduces the proton resonance width within 0.2 MeV,whose magnitude depends on the specific nucleus and the quantum numbers of resonant states.Nuclear single-proton resonances are sensitive to the Coulomb field, while the exchange term of Coulomb field is usually neglected due to its nonlocality. By combining the complex scaling method with the relativistic mean-field model, the influence of the Coulomb exchange term on the single-proton resonances is investigated by taking Sn isotopes and N = 82 isotones as examples. I t is found that the Coulomb exchange term reduces the single-proton resonance energy within the range of 0.4-0.6 MeV and leads to similar isotopic and isotonic trends of the resonance energy as those without the Coulomb exchange term. Moreover, the single-proton resonance width is also reduced by the Coulomb exchange term, whose influence generally decreases with the increasing neutron number and increases with the increasing proton number. However, the influence of the Coulomb exchange term cannot change the trend of the resonance width with respect to the neutron number and proton number. Furthermore, the influence of the Coulomb exchange term on the resonance width is investigated for the doubly magic nuclei 40Ca, 5678N i, 100 132Sn, and 208Pb. It is found that the Coulomb exchange term reduces the proton resonance width within 0.2 MeV, whose magnitude depends on the specific nucleus and the quantum numbers of resonant states.

关 键 词：共振能量 库仑场 交换项 质子数 相对论平均场模型 共振宽度 中子数 非定域性 

分 类 号：O571[理学—粒子物理与原子核物理]