A coherent microscopic picture for the exotic structure of 11Be

Abstract

The neutron-rich nucleus ¹¹Be is one of the most enigmatic exotic nuclei in the periodic table. It exhibits a multitude of unique and intriguing phenomena within a single nucleus, including the halo phenomenon, clustering structure, and parity inversion. A unified description of these exotic properties represents a significant challenge for the nuclear physics field. By employing the axially deformed relativistic Hartree-Fock-Bogoliubov (D-RHFB) model, we have successfully reproduced the parity inversion and the one-neutron halo in ¹¹Be, and revealed the underlying cluster structure. It is found that the intrusion of the sd-shell, which results in the parity inversion, is coherently connected with the halo and cluster structures. In particular, the s-wave is responsible for the halo formation, and the mixing of $2s_{1/2}$- and $1d_{5/2}$-waves enhances the cluster structure. This work elucidates the coherence between the parity inversion and the halo/cluster structures of ¹¹Be, and addresses the long-standing challenge of providing a unified explanation for the multiple exotic phenomena observed in ¹¹Be.