The Island of Inversion at $N=40$

TL;DR

This paper reviews recent experimental findings on the N=40 Island of Inversion, highlighting shell evolution and the dominance of deformed intruder configurations in exotic nuclei, using advanced detection techniques.

Contribution

It provides an overview of recent experimental results on the N=40 Island of Inversion, emphasizing the role of shell evolution and novel experimental methods.

Findings

Shell closures at N=40 can disappear in exotic nuclei.

Deformed intruder configurations dominate the ground state.

Experimental techniques like MINOS and DALI2 are crucial for these studies.

Abstract

Our understanding of the structure of atomic nuclei largely derives from the nuclear shell model, which has proven widely successful. Further test to our interpretation of the nuclear properties is provided by the study of shell evolution. Increasing experimental information has shown that the nuclear energy shells change when going towards the most exotic nuclei, in turn making some shell closures disappear while others arise. In particular, the $N=40$ sub-shell closure has been the subject of extensive research due to the emergence of a so-called Island of Inversion, where deformed intruder configurations dominate the wave function of the ground state. An overview of recent experimental results in the $N=40$ Island of Inversion, particularly those performed with the combination of the MINOS hydrogen target and the DALI2 $\gamma$-ray array at the RIBF are discussed.