Related papers: Shell evolution approaching the N=20 island of inv…
We observed a new isomeric gamma transition at 168 keV in $^{36}$Mg, with a half-life of T$_{1/2}$=[130-500]$(\pm40)(^{+800}_{-20})_{sys}$ ns. We propose that the observed transition de-excites a new 0$^+$ isomeric state and populates the…
Shell evolution in exotic nuclei is investigated with large-scale shell-model calculations. After presenting that the central and tensor forces produce distinctive ways of shell evolution, we show several recent results: (i) evolution of…
Starting from a chiral two- plus three-nucleon interaction, we perform a systematic study of the low-lying states of neutron-rich nuclei around $N=20$ using the in-medium generator coordinate method (IM-GCM), which combines the…
We investigated the evolution of shell structure at $N=32$ and 34 in neutron-rich nuclei beyond the stability line using realistic nuclear forces, employing the state-of-the-art valence-space in-medium similarity renormalization group…
In the present work, we have reported comprehensive study of the $sd$-shell nuclei Si and P with neutron number varying from $N = 9$ to $N = 20$ using the microscopic effective valence shell interactions, namely, N3LO, JISP16 and DJ16A.…
Large Scale Shell Model calculations (SM-CI) predict that the region of deformation which comprises the heaviest Chromium and Iron isotopes at and beyond N=40 will merge with a new one at N=50 in an astonishing parallel to the N=20 and N=28…
The unbound excited states of the neutron drip-line isotope 24O have been investigated via the 24O(p,p')23O+n reaction in inverse kinematics at a beam energy of 62 MeV/nucleon. The decay energy spectrum of 24O* was reconstructed from the…
To improve the effective interactions in the pf shell, it is important to measure the single particle- and hole- states near the N=28 shell gap. In this paper, the neutron spectroscopic factors of hole-states from the unstable neutron-rich…
The evolution of the N=50 gap is analyzed as a function of the occupation of the proton f5/2 and p3/2 orbits. It is based on experimental atomic masses, using three different methods of one or two-neutron separation energies of ground or…
The nucleus $^{29}$Ne is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder $f_{7/2}$-state, which would place $^{29}$Ne firmly inside the island of inversion, has yet been observed.…
Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed…
\item[Background] Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. \item[Purpose] Extend our knowledge about the…
We evaluate the allowed $\beta^-$-decay properties of nuclei with $Z = 8 - 15$ systematically under the framework of the nuclear shell model with the use of the valence space Hamiltonians derived from modern $ab~intio$ methods, such as…
Shell structures in the N\simeq Z nucleus ^{17}O and the neutron-rich oxygen isotopes ^{23}O and ^{25}O are microscopically described by calculating single-particle energies with modern nucleon-nucleon interactions within the framework of…
We report first precision mass measurements of the $1/2^-$ isomeric and $9/2^+$ ground states of $^{101}$In. The determined isomeric excitation energy continues a smooth trend of odd-$A$ indium isotopes up to the immediate vicinity of…
The structure of the neutron rich sodium isotopes 31,32,33Na was investigated by means of in-beam gammaray spectroscopy following one-neutron knockout and inelastic scattering of radioactive beams provided by the RIKEN Radioactive Ion Beam…
The separation between single particle levels in nuclei plays the dominant role in determining the location of the neutron drip line. The separation also provides a test of current crossed shell model interactions if the experimental data…
The energy of the first excited state in the neutron-rich N=28 nucleus 45Cl has been established via in-beam gamma-ray spectroscopy following proton removal. This energy value completes the systematics of the E(1/2^+_1)-E(3/2^+_1) level…
Detailed spectroscopy of the neutron-unbound nucleus $^{28}$F has been performed for the first time following proton/neutron removal from $^{29}$Ne/$^{29}$F beams at energies around 230 MeV/nucleon. The invariant-mass spectra were…
A systematic study of neutron-hole strength in the N = 81 nuclei 137Ba, 139Ce, 141Nd and 143Sm is reported. The single-neutron removal reactions (p,d) and (3He,4He) were measured at energies of 23 and 34 MeV, respectively. Spectroscopic…