Work

Proton–Neutron Pair Correlations in Neutron-Rich Nuclei: Analysis of the Static Polarizability for the Response of Proton–Neutron Pair Transfers

Year: 2026

Type: article

Abstract: Nuclear pairing is a well-established many-body correlation, particularly among like particles in the spin-singlet channel. However, the strength of spin-triplet proton–neutron (pn) pairing in nuclei remains a long-standing, unresolved issue. In this work, we investigate the relative strength of spin-triplet pn pairing compared to its spin-singlet one by introducing and analyzing the polarizability of the response to pn-pair transfers. To this end, we employ the nuclear energy-density functional method, where the ground state of the target nucleus is described within the Hartree–Fock–Bogoliubov approximation to account for the conventional superfluidity of like-particle pairs. The response to pn-pair transfers is subsequently analyzed using the pn quasiparticle random-phase approximation. We find that the spin-singlet pn-pair correlation peaks at $N=Z$ and decreases monotonically with increasing neutron excess. In contrast, the spin-triplet pn-pair correlation exhibits a nonmonotonic dependence on the neutron number; it is enhanced when pn-pair transfers involving the $\pi j_{gt} \otimes \nu j_{lt} $ configuration occur at low energies. These results demonstrate that the shell effect, which uniquely manifests in the spin-triplet channel, serves as a key indicator of the overall pn-pair correlation strength.

Source: Progress of Theoretical and Experimental Physics

DOI: 10.1093/ptep/ptag172

Author: Kenichi Yoshida

Institutions: University of Tsukuba, Tsukuba University of Technology, RIKEN Nishina Center, The University of Osaka

Language: English

Topic: Nuclear physics research studies

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $979