Spatial correlation of a particle-hole pair with a repulsive isovector interaction

TL;DR

This paper investigates the spatial correlation of particle-hole pairs in specific nuclei using Hartree-Fock+Tamm-Dancoff approximation, revealing a repulsive isovector interaction that contrasts with neutron pairing correlations.

Contribution

It demonstrates the repulsive nature of the isovector residual interaction affecting particle-hole correlations in nuclei, using Skyrme interaction calculations.

Findings

Large two-body density concentration opposite to the core nucleus

Repulsive isovector interaction contrasts with neutron pairing

Potential experimental implications discussed

Abstract

We study the spatial correlation of a particle-hole pair in the isovector channel in $^{56}$Co and $^{40}$K nuclei. To this end, we employ the Hartree-Fock+Tamm-Dancoff approximation with the Skyrme interaction. We find a large concentration of the two-body density at positions where the neutron particle and the proton hole states locate on the opposite side to each other with respect to the core nucleus. This feature originates from a repulsive nature of the isovector residual interaction, which is in stark contrast to the dineutron correlation with an attractive pairing interaction between the valence neutrons discussed e.g., in $^{11}$Li and $^6$He. A possible experimental implication of the repulsive correlation is also discussed.