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arXiv 1503.08568nucl-ex
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$^{28}$ Na的光谱学:壳层向滴线的演化

Spectroscopy of $^{28}$Na: shell evolution toward the drip line

A. Lepailleur, K. Wimmer, A. Mutschler, O. Sorlin, V. Bader, C. Bancroft, D. Barofsky, B. Bastin, T. Baugher, D. Bazin, V. Bildstein, C. Borcea, R. Borcea, B. A… 展开作者

A. Lepailleur, K. Wimmer, A. Mutschler, O. Sorlin, V. Bader, C. Bancroft, D. Barofsky, B. Bastin, T. Baugher, D. Bazin, V. Bildstein, C. Borcea, R. Borcea, B. A. Brown, L. Caceres, A. Gade, L. Gaudefroy, S. Grévy, G. F. Grinyer, H. Iwasaki, E. Khan, T. Kröll, C. Langer, A. Lemasson, O. Llidoo, J. Lloyd, F. Negoita, F. de Oliveira Santos, G. Perdikakis, F. Recchia, T. Redpath, T. Roger, F. Rotaru, S. Saenz, M. -G. Saint-Laurent, D. Smalley, D. Sohler, M. Stanoiu, S. R. Stroberg, J. C. Thomas, M. Vandebrouck, D. Weisshaar, A. Westerberg

摘要:

利用GANIL/LISE装置上注入$^{28}$ Ne离子的$β$ -衰变和NSCL/S800装置上的在束$γ$ -射线谱研究了$^{28}$ Na的激发态。提出了新的正宇称态(J $^π$ = 3,4 $^+$)和负宇称态(J $^π$ =1-5 $^-$).前者是由0 d $\_{5/2}$质子和0 d $\_{3/2}$中子之间的耦合引起的,而后者是由于与1 p $\_{3/2}$或0 f $\_{7/2}$中子的耦合引起的。虽然J $^π$ =1-4 $^+$态之间的相对能量在N=17的同位素中用USDA相互作用很好地再现,在$^{26}$ F和$^{30}$ Al之间观察到基态结合能的逐渐移动(约500 keV)。这表明当从稳定性移动到滴线时质子-中子0 d $\_{5/2}$-0 d $\_{3/2}$有效相互作用的可能变化。在1.5 MeV附近J $^π$ =1-4 $^-$负宇称态的存在以及在2.5 MeV附近J $^π$ =5 $^-$态的候选者的存在进一步支持了N=20能隙的坍缩以及Z=12以下0 f $\_{7/2}$和1 p $\_{3/2}$能级之间的反转。在壳模型和EDF计算的框架下讨论了这些特征,预测了$^{26}$ F和$^{25}$ O核低能谱中的负宇称态.

英文摘要:

Excited states in $^{28}$Na have been studied using the $β$-decay of implanted $^{28}$Ne ions at GANIL/LISE as well as the in-beam $γ$-ray spectroscopy at the NSCL/S800 facility. New states of positive (J$^π$=3,4$^+$) and negative (J$^π$=1-5$^-$) parity are proposed. The former arise from the coupling between 0d$\_{5/2}$ protons and a 0d$\_{3/2}$ neutron, while the latter are due to couplings with 1p$\_{3/2}$ or 0f$\_{7/2}$ neutrons. While the relative energies between the J$^π$=1-4$^+$ states are well reproduced with the USDA interaction in the N=17 isotones, a progressive shift in the ground state binding energy (by about 500 keV) is observed between $^{26}$F and $^{30}$Al. This points to a possible change in the proton-neutron 0d$\_{5/2}$-0d$\_{3/2}$ effective interaction when moving from stability to the drip line. The presence of J$^π$=1-4$^-$ negative parity states around 1.5 MeV as well as of a candidate for a J$^π$=5$^-$ state around 2.5 MeV give further support to the collapse of the N=20 gap and to the inversion between the 0f$\_{7/2}$ and 1p$\_{3/2}$ levels below Z=12. These features are discussed in the framework of Shell Model and EDF calculations, leading to predicted negative parity states in the low energy spectra of the $^{26}$F and $^{25}$O nuclei.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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