Study on deformed halo nucleus $^{31}$Ne with Glauber model based on microscopic self-consistent structures

Abstract

We study the exotic deformed nucleus 31 Ne using an approach that combines self-consistent structure and reaction theory. We utilize the fully-relativistic, microscopic deformed Hartree-Bogoliubov theory in continuum (DRHBc) to demonstrate that deformation and pairing correlations give rise to a halo structure with large-amplitude p-wave configuration in 31 Ne. We then use the valence nucleon wave functions and angle-averaged density distributions of 30 Ne from this model as input for a Glauber reaction model to study the observables of neutron-rich Neon isotopes and search for halo signatures. Our predictions of the reaction cross sections of these exotic Neon isotopes on a Carbon target can better reproduce the experimental data than those from relativistic mean field model for a spherical shape with resonances and pairing correlations contributions, as well as those from a Skyrme-Hartree-Fock model. The one-neutron removal cross section at 240 MeV/nucleon, the inclusive longitudinal momentum distribution of the 30 Ne, and the valence neutron residues from the 31 Ne breakup reaction are largely improved over previous theoretical predictions and agree well with data. These reaction data indicate a dilute density distribution in coordinate space and are a canonical signature of a halo structure.

Self-consistent description of the halo nature of 31Ne with continuum and pairing correlations

“…Results: Our predictions of total reaction and one-neutron removal cross sections of 31 Ne on a Carbon target were significantly enhanced compared with those of neighboring Neon isotopes, agreeing with measurements at 240 MeV/nucleon and consistent with a single neutron halo. Furthermore, our calculations of the inclusive longitudinal momentum distribution of the 30 Ne and valence neutron residues from the 31 Ne breakup reaction indicate a dilute density distribution in coordinate space, another halo signature. Conclusions: We give a full description of the halo nature of 31 Ne that includes a self-consistent use of pairing and continuum contributions that makes predictions consistent with reaction…”

“…In our previous study [15], we used the RAB approach to describe the structure of each of the exotic 27−31 Ne nuclei as a core plus a single valence neutron in a resonant orbital. Since the density distribution of 30 Ne and 31 Ne are crucial input in Glauber model, we show them in figure 1. It can be clearly seen that the density distribution of 31 Ne has a larger spatial dilution than that of 30 Ne, which is consistent with a halo structure in 31 Ne.…”

“…Since the density distribution of 30 Ne and 31 Ne are crucial input in Glauber model, we show them in figure 1. It can be clearly seen that the density distribution of 31 Ne has a larger spatial dilution than that of 30 Ne, which is consistent with a halo structure in 31 Ne. The phase-shift function in equation ( 3) is calculated by core density ρ C (r), target density ρ T (r), and profile function.…”

“…These results were analyzed for evidence of neutron halo formation in 31 Ne due to a competition of the occupation for unbound resonant orbitals and the pairing correlations. Based on a radius increase from 30 Ne to 31 Ne, that is much larger than the increase from 29 Ne to 30 Ne, and a simultaneous decrease in the neutron separation energy, a p-orbital 1n halo structure was predicted for 31 Ne. Later that year, the spin and parity of its valence neutron was confirmed from experiment [16], consistent with our predictions, and finally 31 Ne was determined to have a p-orbital halo structure.…”

“…Evidence of halo structure has been overwhelmingly based on total reaction cross sections, Coulomb breakup cross sections, nucleon removal cross sections, and momentum distributions following nuclear breakup [1]. While semi-classical (e.g., Glauber-like [17,18]) cross section models usually work well at the high energies of these measurements, attempts to explain the trends (i.e., large increase) in the measured cross section of 31 Ne bombarding a 12 C target with self-consistent theoretical reaction models, without any additional effects, have smaller increase from 30 Ne to 31 Ne than that of measured data. For example, structure input from a microscopic self-consistent model within non-relativistic mean field framework, i.e., a Skyrme Hartree Fock (SHF) model, were used [19] as input for a Glauber model, but underestimated the measured large increase in the interaction cross section at 31 Ne (compared to 30 Ne), regardless of the force (e.g., SLy4 or SkM * ) used in the model.…”