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Shin, I. J.

Publications and source records attributed to Shin, I. J..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

SS-HORSE extension of the no-core shell model: Application to resonances in He 7

Theoretical ab initio studies of resonances in the unbound 7 He nucleus are presented. We perform no-core shell-model calculations with NN interactions Daejeon16 and JISP16 and utilize the SS-HORSE method to calculate the S matrix for two-body channels n + 6 He and n + 6 He* with 6He respectively in the ground and excited 2 + states as well as for the four-body democratic decay channel 4 He + n + n + n. The resonant energies and widths are obtained by numerical location of the S-matrix poles. Here, we describe all experimentally known 7 He resonances and suggest an interpretation of an observed wide resonance of unknown spin-parity.

6 ≤ A ≤ 19↗
DOE OSTI2019

Effective interactions in the s d shell

We perform here a quantitative study of the microscopic effective shell-model interactions in the valence sd shell, obtained from modern nucleon-nucleon potentials, chiral N3LO, JISP16 and Daejeon16, using No-Core Shell-Model wave functions and the Okubo-Lee-Suzuki transformation. We investigate the monopole properties of those interactions in comparison with the phenomenological universal sd-shell interaction, USDB. Theoretical binding energies and low-energy spectra of O isotopes and of selected sd-shell nuclei, are presented. We conclude that there is a noticeable improvement in the quality of the effective interaction when it is derived from the Daejeon16 potential. We show that its proton-neutron centroids are consistent with those from USDB. We then propose monopole modifications of the Daejeon16 centroids in order to provide an adjusted interaction yielding significantly improved agreement with the experiment. A spin-tensor decomposition of two-body effective interactions is applied in order to extract more information on the structure of the centroids and to understand the reason for deficiencies arising from our current theoretical approximations. The concern of the possible role of the three-nucleon forces is addressed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Description of Continuum Spectrum States of Light Nuclei in the Shell Model

The SS-HORSE method is applied to describe the scattering of nucleons by light nuclei based on calculations within the No-Core Shell Model with JISP16 and Daejeon16 NN interactions. The resonant states in {sup 5}He, {sup 5}Li, and {sup 7}He nuclei have been investigated. The SS-HORSE method generalized to the case of the democratic decay is also applied to study a four-neutron system (tetraneutron). The calculations with JISP16 and Daejeon16 and with chiral NN interactions indicate the existence of a rather narrow low-energy tetraneutron resonance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗