Speaker
Prof.
Wen Hui LONG
(School of Nuclear Science and Technology, Lanzhou University, 730000 Lanzhou, China)
Description
The continuous magic nature at $N=32$ and $34$ in Ca isotopes are illustrated by using the relativistic Hartree-Fock (RHF) Lagrangian PKA1 as referred to recent experiments. It is found that large spin-orbit (SO) splitting of $\nu$2p orbits presents the $N=32$ shell in $^{52}$Ca, whereas significantly reduced $\nu$2p splitting, together with nearly unchanged $\nu$1f one, leads to the magicity $N=34$ in $^{54}$Ca. Such essential changes of the $\nu$2p splitting can be interpreted self-consistently, following the density evolution from central-bumped structures in $^{52}$Ca to the central-flat (proton) and even central-depressed (neutron) ones in $^{54}$Ca. Moreover, it is proved that the dramatic density evolution originates from the strong repulsive interaction between the "Dirac inversion partners" (DIPs) $(\nu2p_{1/2},\nu s_{1/2})$. Finally, we also reveal the mechanism for the appearance of new magicity $N=32$, by analyzing the significant role played by $s_{1/2}$ orbits, which determines the SO spitting of $\nu 2p$ orbits through the strong couplings with the DIP $\nu 2p_{1/2}$. As a result, $^{48}$S is predicted to be the last even isotone preserving the magicity $N=32$ on the proton-deficient side, and together with the predicted proton subshell $Z=16$, it can be also a doubly magic nucleus.
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Primary author
Prof.
Wen Hui LONG
(School of Nuclear Science and Technology, Lanzhou University, 730000 Lanzhou, China)
