Evolution of single-particle structure near the N=20 island of inversion

Patrick T Macgregor ,T L Tang,G De Angelis,D K Sharp,O Poleshchuk,I Martel,R D Page,R S Lubna,B P Kay,E F Baader,R Raabe,S J Freeman,J Konki,D G Mcneel,W N Catford,F Recchia,M Labiche,P A Butler,C R Hoffman,B D Cropper,Thilo Kroll ,I Lazarus ,Liam Gaffney ,María José García Borge ,Jien Yang

doi:10.1103/physrevc.104.l051301

Abstract

The single-particle properties of $^{29}\mathrm{Mg}$ have been investigated via a measurement of the $^{28}\mathrm{Mg}(d,p)^{29}\mathrm{Mg}$ reaction, in inverse kinematics, using the ISOLDE Solenoidal Spectrometer. The negative-parity intruder states from the $fp$ shell have been identified and used to benchmark modern shell-model calculations. The systematic data on the single-particle centroids along the $N=17$ isotones show good agreement with shell-model predictions in describing the observed trends from stability toward $^{25}\mathrm{O}$. However, there is also evidence that the effect of the finite geometry of the nuclear potential is playing a role on the behavior of the $p$ orbitals near the particle-emission threshold.

Highlights

The single-particle properties of 29Mg have been investigated via a measurement of the 28Mg(d,p) 29Mg reaction, in inverse kinematics, using the ISOLDE Solenoidal Spectrometer
A weaker shell gap enhances the contribution of intruder configurations until, inside the island, they become the dominant component of the ground state
The N = 20 shell gap disappears along N = 16 as protons are removed; the separation of the νd3/2 orbital and the ν f p shell reduces and a new

Summary

Introduction

The single-particle properties of 29Mg have been investigated via a measurement of the 28Mg(d,p) 29Mg reaction, in inverse kinematics, using the ISOLDE Solenoidal Spectrometer. Single-particle energies in the WBP interaction [6] needed to be shifted by 1.8 and 0.5 MeV for ν f7/2 and ν p3/2 orbitals, respectively, to better match data in 34P19 [7].

Results

Conclusion