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arXiv · 2412.20479

Dipole response of deformed halo nuclei $^{31}$Ne and $^{37}$Mg

Xiao Lu·Hiroyuki Sagawa·Shan-Gui Zhou
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Abstract

We study the soft electric dipole ($E1$) response of deformed halo nuclei $^{31}$Ne and $^{37}$Mg using a deformed Woods-Saxon potential, with the potential depth adjusted to reproduce empirical separation energy of last neutron orbit, i.e., 150 keV for $^{31}$Ne and 220 keV for $^{37}$Mg. The configuration dependence of the $E1$ strength near the neutron threshold is pointed out. The halo configurations $[321]3/2$ at $\beta_2=0.5$ and $[330]1/2$ at $\beta_2=0.24$ in $^{31}$Ne contain large amplitudes of halo $p$-shell orbits, which significantly enhance the threshold strength by several times compared to the non-halo configuration $[202]5/2$ at $\beta_2=0.32$. In $^{37}$Mg, the last neutron configuration is assigned as $[321]1/2$ at a large deformation of $\beta_2=0.46$, which involves a halo $p$-shell configuration that significantly enhances the soft dipole strength. This enhancement is about 60\% larger than that of the $[321]3/2$ configuration in $^{31}$Ne because of large $p$-shell probability in $^{37}$Mg. Experimental confirmation of the soft dipole strength is highly desired to determine the deformation and the configuration of the last neutron orbits both in $^{31}$Ne and $^{37}$Mg.

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Xiao Lu, Hiroyuki Sagawa, Shan-Gui Zhou. 2024-12-29. Dipole response of deformed halo nuclei $^{31}$Ne and $^{37}$Mg. https://arxiv.org/abs/2412.20479

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