Non-trivial effect for the large radius at the dripline of Oxygen isotopes

Abstract

The anomalous large radii are exotic phenomena observed around the neutron dripline. Around the neutron dripline, the weak binding of the last bound neutron(s) causes the drastic increase of the radius, which is called neutron halo structure. Although the nucleus ${}^{24}$O is located at the dripline of Oxygen isotopes, the separation energies of one and two neutron(s) are 4.19 MeV and 6.92 MeV, respectively. In spite of this enough binding, the enhancement of the matter radius is observed. In this study, we microscopically describe the structure change of ${}^{22}$O core in ${}^{24}$O and explain the observed large radius based on the cluster model. Two degrees of freedom for the large radius; the relative distances among four $\alpha$ clusters and size of each $\alpha$ cluster are examined, where Tohsaki interaction, which has finite range three-body terms is employed. The nucleus ${}^{24}$O has the almost the same amount of the clusterization compared with ${}^{22}$O, but the expansion of each $\alpha$ cluster plays an important role. When two neutrons are added to ${}^{22}$O at the center, the expansion of each $\alpha$ clusters is energetically more favored than enhancing the clustering for reducing the kinetic energy of the neutrons. The calculated rms matter radius of ${}^{22}$O and ${}^{24}$O are 2.75 fm and 2.92 fm, respectively. Although these are slightly smaller than the experimental values, the jump at ${}^{24}$O from ${}^{22}$O is reproduced.

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Cited by in corpus (12)

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• Explicit inclusion of spin-orbit contribution in THSR wave function
• Density profiles near nuclear surface of ${}^{44,52}$Ti: An indication of $\alpha$ clustering
• Imprints of $\alpha$ clustering in the density profiles of ${}^{12}$C and ${}^{16}$O
• Evidence of bicluster structure in the ground state of ${}^{20}$Ne
• ${}^8$He and ${}^9$Li cluster structures in light nuclei
• Consistent description for cluster dynamics and single-particle correlation
• Role of Tensor Interaction as Salvation of Cluster Structure in ${}^{44}$Ti
• Tensor correlations in ${}^4$He and ${}^8$Be with antisymmetrized quasi cluster model
• Coulomb Energy of alpha-Aggregates on a Soap Bubble Shape
• Persistence of cluster structure in the ground state of ${}^{11}$B
• Cluster-shell competition and effect of adding hyperons