Microscopic study of the deformed neutron halo of ${}^{31}\mathrm{Ne}$

The properties of the deformed halo of ${}^{31}\mathrm{Ne}$ are discussed using the antisymmetrized molecular dynamics plus resonating group method $(\mathrm{AMD}+\mathrm{RGM})$. The $\mathrm{AMD}+\mathrm{RGM}$ calculations describe a large neutron radius for the ground state and reveal that the ground state is dominated by core-excited components. The resonant states are also investigated by applying the analytical continuation of the coupling constant. It is found that the first excited state (the $5/2^{-}$ state) is also dominated by core-excited components and has a small decay width, whereas the second excited state (the $7/2^{-}$ state) is dominated by the valence neutron in the $f$ wave coupled to the ground state of ${}^{30}\mathrm{Ne}$.

Figure 1

Schematic illustration of an $\mathrm{AMD}+\mathrm{RGM}$ basis wave function for the ${}^{30}\mathrm{Ne}+n$ system.

Figure 2

Energy curves of ${}^{30}\mathrm{Ne}$ and ${}^{31}\mathrm{Ne}$ obtained from $\beta$-constrained variational calculations.

Figure 3

(a) Single-particle energies of the five most weakly bound neutrons. Only the occupied orbits are calculated in the $\mathrm{AMD}+\mathrm{GCM}$ framework. (b) Occupation numbers of the $p$ and $f$ waves from the five most weakly bound neutrons.

Figure 4

Energy spectrum of ${}^{30}\mathrm{Ne}$ and ${}^{31}\mathrm{Ne}$ relative to the ground state of ${}^{30}\mathrm{Ne}$. The $\mathrm{AMD}+\mathrm{GCM}$ results are denoted as “GCM” and the $\mathrm{AMD}+\mathrm{RGM}$ results as “RGM.”

Figure 5

Wave functions (overlap functions) of the ground state of ${}^{31}\mathrm{Ne}$ in the (a) $0_1^{+}\otimes p_{3/2}$, (b) $2_1^{+}\otimes p_{3/2}\left(2_1^{+}\right)$, and (c) $2_1^{+}\otimes f_{7/2}\left(2_1^{+}\right)$ channels calculated using the $\mathrm{AMD}+\mathrm{GCM}$ and $\mathrm{AMD}+\mathrm{RGM}$. The amplitudes are arbitrarily normalized for presentation. The dotted lines show the correct asymptotics at large distances, where the interaction between ${}^{30}\mathrm{Ne}$ and the valence neutron is negligible.