Speaker
Description
The latest generation of radioactive ion beam facilities provides unparalleled access to neutron-rich unstable isotopes. One of the areas of active investigation is the study of the shell evolution near the neutron magic numbers N=20 [1-4] and N=28 [5-6] for such unstable nuclei. The nuclei near these magic numbers display exotic structural features such as dampening of shell gaps, formation of halos, and deformed structures.
Recently, the 29F system, a light neutron-rich N=20 isotone, was identified as the heaviest two-neutron Borromean-halo nucleus found till date [1-4]. Motivated by this observation, it is interesting to explore the “N=28” shell closure for nuclei with a small proton number as well, to see whether we can find similar Borromean structure formation.
In this talk, I will compare and contrast the shell evolution across the neutron magic numbers N=20 and 28 within a three-body (core+N+N) framework based on the hyperspherical-harmonics formalism by using an analytical-transformed harmonic-oscillator basis. New three-body results will be presented for the ground state structural properties of putative two-neutron Borromean halos in Na and Mg isotopes with N=28 [7].
[1] S. Bagchi, et al., PRL 124, 222504 (2020).
[2] J. Singh, et al., PRC 101, 024310 (2020).
[3] J. Casal, J. Singh, et al., PRC 102, 064627 (2020).
[4] L. Fortunato, et al., Commun. Phys. 3, 132 (2020).
[5] D. S. Ahn, et al., PRL 129, 212502 (2022).
[6] K.Y. Zhang, et al., PRC 107, L041303 (2023).
[7] Jagjit Singh et al., arXiv:2401.05160 [nucl-th] (2024).
