The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ri...The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou.The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 keV.When compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)keV.The excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory.The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.展开更多
Mirror energy difference is a key observable in isospin symmetry breaking,containing rich information about nuclear structure.Understanding the mechanisms underlying mirror energy difference is important in nuclear ph...Mirror energy difference is a key observable in isospin symmetry breaking,containing rich information about nuclear structure.Understanding the mechanisms underlying mirror energy difference is important in nuclear physics.In the present work,we extensively investigated mirror energy difference using ab initio valence-space inmedium similarity renormalization group approach,focusing specifically on sd-shell nuclei.The low-lying spectra of Al isotopes and N=8 isotones,together with their mirror nuclei,were calculated,followed by a systematic analysis of the evolution of the mirror energy difference.The results suggest that the large mirror energy difference is mainly caused by the weakly-bound effects and large average occupations of the 1s1/2 orbit.Lastly,we compare the results of our ab initio calculations with shell model results,elucidating the relationship and coherence between these two models.展开更多
基金Supported in part by the Strategic Priority Research Program of Chinese Academy of Sciences (XDB34000000)the CAS Project for Young Scientists in Basic Research (YSBR-002)+4 种基金the National Nature Science Foundation of China (12135017,12121005,11975280,12105333,12205340,12322507,12305126,12305151)the Gansu Natural Science Foundation (22JR5RA123,23JRRA614)the National Key R&D Program of China (2021YFA1601500)Support from the Youth Innovation Promotion Association of Chinese Academy of Sciences (2021419,2022423)support from Young Scholar of Regional Development,CAS ([2023]15).
文摘The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou.The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 keV.When compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)keV.The excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory.The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.
基金the National Natural Science Foundation of China(12205340,11975282)the Gansu Natural Science Foundation(22JR5RA123)+3 种基金the Special Research Assistant Project of the Chinese Academy of Sciencesthe Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)the Key Research Program of the Chinese Academy of Sciences(XDPB15)the State Key Laboratory of Nuclear Physics and Technology,Peking University(NPT2020KFY13)。
文摘Mirror energy difference is a key observable in isospin symmetry breaking,containing rich information about nuclear structure.Understanding the mechanisms underlying mirror energy difference is important in nuclear physics.In the present work,we extensively investigated mirror energy difference using ab initio valence-space inmedium similarity renormalization group approach,focusing specifically on sd-shell nuclei.The low-lying spectra of Al isotopes and N=8 isotones,together with their mirror nuclei,were calculated,followed by a systematic analysis of the evolution of the mirror energy difference.The results suggest that the large mirror energy difference is mainly caused by the weakly-bound effects and large average occupations of the 1s1/2 orbit.Lastly,we compare the results of our ab initio calculations with shell model results,elucidating the relationship and coherence between these two models.
