Shell evolution is crucial for understanding nuclear structures across the nuclear chart.In this work,we employed the ab initio valence space in-medium similarity renormalization group with chiral nucleon-nucleon and ...Shell evolution is crucial for understanding nuclear structures across the nuclear chart.In this work,we employed the ab initio valence space in-medium similarity renormalization group with chiral nucleon-nucleon and three-nucleon interactions to study neutron-rich Si,S,Ar,and Ca isotopes,particularly focusing on nuclei near N=32,34.We systematically analyzed both neutron and proton shell evolutions by examining the excitation energies of the first 2^(+)states and the effective single-particle energies.Our calculations show that the N=32 sub-shell gradually weakens as protons are removed from the doubly magic nucleus^(52)Ca,eventually disappearing in 46si.Conversely,the strength of the N=34 sub-shell is enhanced with the removal of protons from^(54)Ca.Furthermore,our results indicate the existence of the proton Z=14 sub-shell in neutron-rich Si isotopes.These findings suggest that^(48)Si is a doubly magic nucleus,with the excitation energy of the first 2^(+)state around 2.49 MeV,which is approximately 400 keV higher than that of^(54)Ca.This value is comparable to those of other well-known exotic doubly magic nuclei,such as^(52)Ca and^(78)Ni,which is of great interest for further experiments at RIB facilities.In addition,we predicted the low-lying spectra of neutron-rich Si,S,and Ar isotopes,providing new insights for future experiments.展开更多
基金Supported by the National Key R&D Program of China(2024YFE0109800,2024YFE0109802,2023YFA1606403)the National Natural Science Foundation of China(12405141,12205340,12175281,12347106,12475128,12322507,12121005)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022423)the Gansu Natural Science Foundation(22JR5RA123,23JRRA614)the Natural Science Foundation of Henan Province(242300421048).
文摘Shell evolution is crucial for understanding nuclear structures across the nuclear chart.In this work,we employed the ab initio valence space in-medium similarity renormalization group with chiral nucleon-nucleon and three-nucleon interactions to study neutron-rich Si,S,Ar,and Ca isotopes,particularly focusing on nuclei near N=32,34.We systematically analyzed both neutron and proton shell evolutions by examining the excitation energies of the first 2^(+)states and the effective single-particle energies.Our calculations show that the N=32 sub-shell gradually weakens as protons are removed from the doubly magic nucleus^(52)Ca,eventually disappearing in 46si.Conversely,the strength of the N=34 sub-shell is enhanced with the removal of protons from^(54)Ca.Furthermore,our results indicate the existence of the proton Z=14 sub-shell in neutron-rich Si isotopes.These findings suggest that^(48)Si is a doubly magic nucleus,with the excitation energy of the first 2^(+)state around 2.49 MeV,which is approximately 400 keV higher than that of^(54)Ca.This value is comparable to those of other well-known exotic doubly magic nuclei,such as^(52)Ca and^(78)Ni,which is of great interest for further experiments at RIB facilities.In addition,we predicted the low-lying spectra of neutron-rich Si,S,and Ar isotopes,providing new insights for future experiments.
