Narrow Results

We investigate the tensor and pairing correlations in ¹¹Li based on the ⁹Li+n+n model. For ⁹Li, we perform the configuration mixing with the shell model type wave function to introduce the core polarization caused by the tensor and pairing correlations. For ¹¹Li, we perform the coupled ⁹Li+n+n calculation, in which the couplings between the correlations in ⁹Li and the motion of the last two neutrons emerge Pauli-blocking for the p² configuration of ¹¹Li and increases the s² component to develop the halo structure.

We investigate the tensor correlations in He and Li isotopes systematically. We propose the tensor-optimized shell model (TOSM) to describe the strong tensor correlation arising from the bare nuclear force in nuclei. Using TOSM for Li isotopes, we investigate the anomalous structures of ^9,10,11Li based on the ⁹Li+n+n model where the ⁹Li cluster is described by TOSM. As a result, the couplings between the tensor correlation in ⁹Li and the extra two neutrons emerge Pauli-blocking, which naturally increases the s² component to develop the halo structure in ¹¹Li. We further describe the short-range correlation arising from the repulsive core in the bare nuclear force by the unitary correlation operator method (UCOM). We propose the new framework of TOSM+UCOM for the nuclear structure study starting from the bare nuclear force.

The structure nucleus ${}^{19}\mathrm{B}$ is investigated in the Microscopic Cluster Model, using three-body model ${}^{17}\mathrm{B}+n+n$. This model is used to investigate neutron halo features such as binding energy of neutron valence, root-mean-square (rms) of radius and core deformation. All the features are studied in configuration-T and -Y. In this study, theoretical framework is used in the MATLAB software to run the computational calculations. The results are compared with the experimental data.

We show the importance of the tensor correlation on the structures of He and Li isotopes. We develop the tensor optimized shell model (TOSM) to describe the strong tensor correlation of the nuclear force in nuclei. We investigate the exotic structures of ^9,10,11Li based on the ⁹Li+n+n model where TOSM is used for ⁹Li. The coupling between the tensor correlation in ⁹Li and the extra two neutrons emerges Pauli-blocking, which increases the s² component and develops the halo structure in ¹¹Li.

We further treat the short range repulsion of the nuclear force by the unitary correlation operator method (UCOM), while the tensor correlation is described by TOSM. We propose a new approach of TOSM+UCOM to describe nuclei from the nuclear force.

The differential cross-sections of the elastic and inelastic $\alpha {+}^{13}$C scattering have been measured at E$(\alpha )=29$MeV. The radii of the exited states: 3.09 $(1/2^{+})$ and 8.86 $(1/2^{-})$ MeV were determined using the Modified Diffraction Model. The radii of these excited states are larger than that of the ground state of ${}^{13}$C, confirming the suggestion that the 8.86 $(1/2^{-})$ MeV state could be an analog of the Hoyle state in ${}^{12}$C and the 3.09 $(1/2^{+})$ MeV state has a neutron halo. The possibility of coexistence of various exotic states in the structure of the ${}^{13}$C nucleus is shown.

The nuclear shell model with the Skyrme–Hartree–Fock (SHF), as a nonrelativistic approach, and the Relativistic Hartree–Fock–Bogoliubov (RHFB) methods have been used to study the nuclear structure of some exotic nuclei at the proton and neutron drip lines. Different Skyrme parametrizations, in particular SkM*, SkX, SkO, SLy4, Skxs25 and Z, have been used in the nonrelativistic region. In the relativistic region, the density-dependence meson-exchange models and density-dependence point-coupling models are used. Both methods are used to study ground state properties such as binding energy, mass radial density distribution and the corresponding root mean square (rms) mass radii. The fragmentation reaction cross-section is used as an important property to investigate the halo structure. Strong evidence for existence of a neutron halo in ${}^{11}$Li and ${}^{14}$Be and proton halo in ${}^{17}$Ne, ${}^{23}$Al and ${}^{27}$P are found using the SHF model and reaction cross-section. The ability of the SHF model to study the exotic structure with shell model occupation probability is confirmed.

Invariant mass spectroscopy is a powerful tool to study low-lying excitation of the halo nuclei. We have applied the invariant mass spectroscopy to the E1 excitation of ¹¹Li and to the 2⁺ transition of ¹⁴Be. The former study used the Coulomb breakup of ¹¹Li on Pb at 70 MeV/nucleon, which revealed a strong E1 transition at very low excitation energies. Such a strong soft E1 excitation indicated dineutron-like spatial correlation in ¹¹Li. The latter study used inelastic scattering of ¹⁴Be on carbon and proton targets at about 70 MeV/nucleon. The first 2⁺ state was observed in energy spectra for both targets. The extracted deformation parameters were smaller than those of the neighboring ¹²Be nucleus, indicating the hindered collectivity at the drip-line nucleus ¹⁴Be.

Spin-dependent asymmetry was measured for the elastic scattering at 71 MeV/nucleon making use of a solid polarized proton target specially designed for radioactive ion beam experiments. Absolute values of the analyzing power were deduced for the first time from the measured asymmetry and from the target polarization determined via the elastic scattering at 80 MeV/nucleon. Large discrepancy was found between obtained analyzing power data and predictions of g-matrix folding model.