Probing the $N=14$ subshell closure: $g$ factor of the ${}^{26}$Mg(2${}_1^{+}$) state

Abstract

The first-excited state $g$~factor of ${}^{26}$Mg has been measured relative to the $g$ factor of the ${}^{24}$Mg($2_1^{+}$) state using the high-velocity transient-field technique, giving $g=+0.86\pm 0.10$. This new measurement is in strong disagreement with the currently adopted value, but in agreement with the $sd$-shell model using the USDB interaction. The newly measured $g$ factor, along with $E(2_1^{+})$ and $B(E2)$ systematics, signal the closure of the $\nu d_{5/2}$ subshell at $N=14$. The possibility that precise $g$-factor measurements may indicate the onset of neutron $pf$ admixtures in first-excited state even-even magnesium isotopes below ${}^{32}$Mg is discussed and the importance of precise excited-state $g$-factor measurements on $sd$~shell nuclei with $N\ne Z$ to test shell-model wavefunctions is noted.

arXiv comment8 pages, 5 figures

References in corpus (6)

• Magic numbers in exotic nuclei and spin-isospin properties of {\it NN} interaction
• Effective interaction for pf-shell nuclei
• Probing shell structure and shape changes in neutron-rich sulfur isotopes through transient-field g factor measurements on fast radioactive beams of 38S and 40S
• Shell structure underlying the evolution of quadrupole collectivity in S-38 and S-40 probed by transient-field g-factor measurements on fast radioactive beams
• Perturbed angular correlations for Gd in gadolinium: in-beam comparisons of relative magnetizations
• Some notes on the program GKINT: Transient-field g-factor kinematics at intermediate energies

Cited by in corpus (3)

• Apparatus for in-beam hyperfine interactions and $g$-factor measurements: design and operation
• First-excited state $g$ factors in the stable, even Ge and Se isotopes
• Pushing the limits of excited-state $g$-factor measurements