含手征三体力的第一性原理Gamow壳模型计算14O同中子素  

Ab initio Gamow shell model with chiral three-nucleon force for 14O isotones

作　　者：张爽[1] 程泽华 李健国 许志成 许甫荣[1] Shuang Zhang;Zehua Cheng;Jianguo Li;Zhicheng Xu;Furong Xu(School of Physics,Peking University,Beijing 100871,China)

机构地区：[1]北京大学物理学院,北京100871

出　　处：《科学通报》2022年第34期4101-4107,共7页Chinese Science Bulletin

基　　金：国家重点研发计划(2018YFA0404401);国家自然科学基金(11835001,12035001,11921006)资助。

摘　　要：从手征有效场论N^(3)LO两体核力和N^(2)LO三体核力出发,利用第一性原理Gamow壳模型计算研究了质子滴线附近原子核15F~18Mg的基态和低激发态性质.通过计算1s1/2和0d5/2轨道的有效单粒子能与占据概率,分析了18Mg及其镜像核18C基态中的连续态耦合效应.同时考虑手征三体力、连续态耦合和多体关联,计算了18Mg及其镜像核18C 2^(+)态的能量,其镜像能差异相比实空间计算结果得到显著改善.计算给出18Mg 2^(+)激发态比20Mg 2^(+)态高这一现象,分析了其中的机理.基于实空间第一性原理壳模型,预言了20Si和22Si能谱中的2^(+)态位置,为今后实验提供了有用信息.Proton-rich nuclei exhibit many novel phenomena, such as proton emission, proton halo, and Thomas-Ehrman shift. On one hand, due to the Coulomb force, outer protons have a lower nuclear separation threshold and are strongly coupled to the continuum. Such weakly bound nuclei are called the open quantum system. On the other hand, the Coulomb barrier restricts the spatial spread of the weakly-bound outer protons, resulting in that unbound resonance nuclei beyond the proton drip line may have certain lifetimes, e.g., a millisecond lifetime. The interplay of the continuum coupling and Coulomb forces produces a complex pattern in nuclei near the proton-rich drip line, which contains rich and unique structures and dynamic information. These properties lead to new insights into nuclear forces, symmetry breaking between mirror nuclei and many-body correlations.Recent experiment observed the ground state of18Mg via its decay into 4p+14O. The decay of the ground state of this nucleus is consistent with two sequential steps of 2p decay passing through the ground state of16Ne. And another excited state at 1.84 MeV was also observed, which may be the first 2+excited state. The excitation energy of this 2+state is significantly higher than that in18C, which shows a typical Thomas-Ehrman shift. In addition, this 2+excitation energy of18Mg exceeds that of20Mg. It is meaningful to study these novel phenomena through ab initio calculations. However,continuum coupling is important in these proton-rich nuclei, so the continuum degrees of freedom should be treated properly. Using the Berggren basis, the Gamow shell model provides a good description of the interplay between bound state, resonance, and continuum in a self-consistent many-body framework.In the present paper, we employ two-and three-nucleon forces from chiral effective theory, perform the Gamow shell model calculations of15–18C and15F–18Mg with continuum coupling included. The Gamow Hartree-Fock method with three-body force included was used to generate the Berggren b

关 键 词：第一性原理计算 Gamow壳模型 共振和连续态 丰质子核 手征三体力 

分 类 号：O571[理学—粒子物理与原子核物理]