2024/06/06 by Yue, Tong-Gang, Zhang, Zhen, Chen, Lie-Wen · 1 citation
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2406.03844
The recent PREX-2 and CREX data on the model-independent extraction of the charge-weak form factor difference ΔF\rm CW in 208Pb and 48Ca challenge modern nuclear energy density functionals (EDFs) as well as our present understanding on the neutron skin and nuclear symmetry energy. Within the Skyrme-like EDFs, we demonstrate that the isovector spin-orbit interaction can strongly change the ΔF\rm CW in 48Ca while it has essentially no influence on the ΔF\rm CW in 208Pb, mainly due to the eight spin-orbit unpaired 1f7/2 neutrons in 48Ca. To simultaneously describe PREX-2 and CREX data in 1σ error, we find the strength of isovector spin-orbit interaction should be larger than about four times of that in the conventional Skyrme-like EDFs, implying the neutrons and protons have significantly different spin-orbit interaction. To further reconcile the data on electric dipole polarizability in 208Pb and 48Ca, we obtain L ≈ 55 MeV for the slope parameter of the symmetry energy, Δr\rm np(208\rmPb) ≈ 0.19 fm and Δr\rm np(48\rmCa) ≈ 0.12 fm for the neutron skin thickness. The implications of the strong isovector spin-orbit interaction are discussed.