Implications of parity-violating electron scattering experiments on $^{48}$Ca (CREX) and $^{208}$Pb (PREX-II) for nuclear energy density functionals

Abstract

Recent precise parity-violating electron scattering experiments on 48 Ca (CREX) and 208 Pb (PREX-II) provide a new insight on the formation of neutron skin in nuclei. Within the energy density functional (EDF) framework, we investigate the implications of CREX and PREX-II data on nuclear matter symmetry energy and isovector properties of finite nuclei: neutron skin thickness and dipole polarizability. The weak-charge form factors from the CREX and PREX-II experiments are employed directly in constraining the relativistic density-dependent point coupling EDFs. The EDF established with the CREX data acquires considerably smaller values of the symmetry energy parameters, neutron skin thickness and dipole polarizability both for 48 Ca and 208 Pb, in comparison to the EDF obtained using the PREX-II data, and previously established EDFs. Presented analysis shows that CREX and PREX-II experiments could not provide consistent constraints for the isovector sector of the EDFs, and further experimental studies are called for.

Nuclear symmetry energy and the PREX-CREX neutron skin puzzle within the KIDS framework

“…Parity-violating electron scattering experiments have revealed a thin neutron skin in the 48 Ca nucleus (CREX experiment [10]) and a thick neutron skin in 208 Pb (PREX-II experiment [9]). Within standard energy density functional (EDF) theory, the two results appear irreconcilable because description of 48 Ca appears to require a soft symmetry energy (low slope parameter L) and description of 208 Pb requires a stiff symmetry energy (high L) [22,23]. This remains true when uncertainties in the extraction of the neutron skin thickness from the measured parity violating asymmetry are taken into account.…”

Effect of isovector scalar meson on equation of state of dense matter within relativistic mean field model

“…[14] and references therein. First of its kind model independent measurement of neutron skin thickness ∆r np of 208 Pb [15] and 48 Ca [16] in the Jefferesen lab also inspired theoretical studies to take a fresher look at the isovector channel of the nuclear interaction [17][18][19][20][21].…”