Nuclear mass table in density functional approach inspired by neutron-star observations

Background: The nuclear energy-density functional (EDF) approach is widely employed to describe nuclear-matter equations of state (EoS) and the properties of finite nuclei. Recent advancements in neutron-star (NS) observations have imposed constraints on the nuclear EoS. The Korea-IBS-Daegu-SKKU (KIDS) functional has been then developed to satisfy the NS observations and applied to homogeneous nuclear matter and spherical nuclei.

Purpose: We examine the performance of the KIDS functional in this study by calculating the masses and charge radii of even-even nuclei towards the drip lines.

Method: The Kohn-Sham-Bogoliubov equation is solved by taking into account the axial deformation.

Results: The root-mean-square deviations of the binding energy and the charge radius for the KIDS models are 4.5–5.1 MeV and 0.03–0.04 fm, which are comparable to those for existing EDFs. The emergence and development of nuclear deformation in open-shell nuclei are well described. The location of the neutron drip line is according to the nuclear-matter parameter characterizing the low-mass NS.

Conclusions: The NS-observation-inspired EDF offers a reasonable reproduction of the structures of finite nuclei. A future global optimization that incorporates more nuclear data will enhance the accuracy and predictive power of neutron-rich nuclei.

Figure 1

Binding energy residuals between the KIDS results and experiment for 632, 630, 628, and 623 even-even nuclei for the KIDS-A, KIDS-B, KIDS-C, and KIDS-D models, respectively. The residuals are calculated only for the bound nuclei in each model among the available experimental data. Black lines denote the results for O, Ca, Ni, Sn, and Pb isotopes, respectively.

Figure 2

Calculated charge radius difference from the experimental value for 344, 344, 343, and 343 even-even nuclei for the KIDS-A, KIDS-B, KIDS-C, and KIDS-D models, respectively.

Figure 3

Calculated quadrupole deformation ${\beta }_{2,p}$ for bound nuclei obtained by employing the KIDS-A–D models.

Figure 4

Calculated PES of ${}^{78}\mathrm{Ni}$ using the KIDS-A–D models. The result obtained by using the SLy4 functional is included.

Figure 5

Two-neutron separation energy $S_{2n}$ of the rare earth isotopes with $Z=60–70$. The experimental data for JYFLTRAP and CARIBU are obtained from Refs. [48, 49], respectively.

Figure 6

Neutron and proton drip lines predicted by the KIDS models. Filled circles indicate the $E/A$ value taken from AME2020 [37].