Nuclear Theory·nucl-th

Monday·July 3, 2023

7 papers—2 primary·5 cross-listed

01
Improved sd shell effective interactions from Daejeon16
Ik Jae Shin🇰🇷 · Nadezda A. Smirnova🇫🇷 · Andrey M. Shirokov🇷🇺 · Zuxing Yang🇯🇵 · Bruce R. Barrett🇺🇸 · Zhen Li🇫🇷 · Youngman Kim🇰🇷 · Pieter Maris🇺🇸 · James P. Vary🇺🇸
We present new microscopic effective shell-model interactions in the valence sd shell, obtained from the modern Daejeon16 nucleon-nucleon potential using no-core shell-model (NCSM) wave functions of 18F at Nmax=6 (total oscillator quanta of excitation) model space and the Okubo-Lee-Suzuki transformation. First, we explore the convergence properties of our calculations and show that the excitation energies of states in 18F, characterized by the largest valence-like configurations, are reasonably converged and the lowest states are in sensible agreement with experiment. Then, we investigate the monopole properties of that interaction in comparison with the phenomenological universal sd-shell interaction, USDB, and with the previously derived interaction at Nmax=4. Theoretical binding energies and low-energy spectra of the O isotopes, as well as low-energy spectra of a selection of $s d$ -shell nuclei, are presented. We conclude that the use of larger-space NCSM wave functions leads to a noticeable improvement in the quality of the derived effective interaction. We propose monopole modifications of the Daejeon16 centroids which further improve the agreement with experiment throughout the sd shell, as demonstrated by a compilation of spectra contained in Supplemental Material.
nucl-thPRC(2024)·4 citations
02
Repulsive $Λ$ potentials in dense neutron star matter and binding energy of $Λ$ in hypernuclei
Asanosuke Jinno🇯🇵 · Koichi Murase🇯🇵 · Yasushi Nara🇯🇵 · Akira Ohnishi🇯🇵
The repulsive three-body force between the lambda ( $Λ$ ) hyperon and medium nucleons is a key element in solving the hyperon puzzle in neutron stars. We investigate the binding energies of $Λ$ hyperon in hypernuclei to verify the repulsive $Λ$ potentials from the chiral effective field theory ( $χ$ EFT) employing the Skyrme Hartree-Fock method. We find that the $χ$ EFT $Λ$ potential with the $Λ N N$ three-body forces reproduces the existing hypernuclear binding energy data, whereas the $Λ$ binding energies are overestimated without the $Λ N N$ three-body force. Additionally, we search for the parameter space of the $Λ$ potentials by varying the Taylor coefficients of the $Λ$ potential and the effective mass of $Λ$ at the saturation density. Our analysis demonstrates that the parameter region consistent with the $Λ$ binding energy data spans a wide range of the parameter space, including even more repulsive potentials than the $χ$ EFT prediction. We confirm that these strong repulsive $Λ$ potentials suppress the presence of $Λ$ in the neutron star matter. We found that the $Λ$ potentials repulsive at high densities are favored when the depth of the $Λ$ potential at the saturation density, $U_{Λ} (ρ_{0}) = J_{Λ}$ , is $J_{Λ} ≳ - 29 MeV$ , while attractive ones are favored when $J_{Λ} ≲ - 31 MeV$ . This suggests that the future high-resolution data of hypernuclei could rule out the scenario in which $Λ$ s appear through the precise determination of $J_{Λ}$ within the accuracy of $1 MeV$ .
nucl-thnucl-exPRC(2023)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE

Improved sd shell effective interactions from Daejeon16

Repulsive Λ potentials in dense neutron star matter and binding energy of Λ in hypernuclei

Affiliations

Repulsive $Λ$ potentials in dense neutron star matter and binding energy of $Λ$ in hypernuclei