Isoscalar-isovector proton-neutron pairing and quartet condensation in N=Z nuclei

TL;DR

This paper demonstrates that in N=Z nuclei, ground state correlations from isovector and isoscalar pairing can be accurately modeled as a quartet condensate, revealing their coexistence.

Contribution

The study extends the quartet condensation model to include both isovector and isoscalar pairing, providing a high-precision treatment of proton-neutron correlations in N=Z nuclei.

Findings

Isovector and isoscalar pairing correlations coexist in N=Z nuclei.

The extended QCM accurately describes pairing correlations in various nuclei.

Competition between T=1 and T=0 pairing is analyzed in different nuclear models.

Abstract

We show that the correlations generated in the ground state of $N=Z$ nuclei by the isovector and isoscalar pairing forces can be treated with high precision as a condensate of alpha-like quartets. To treat these correlations, the quartet condensation model (QCM) is extended to the treatment of spherically symmetric isovector $(T=1,J=0)$ and isoscalar $(T=0,J=1)$ pairing forces . Within QCM we discuss the competition between $T=1$ and $T=0$ pairing correlations in the case of a two-level model and for $N=Z$ nuclei with nucleons moving in the open shells above $^{16}$O, $^{40}$Ca and $^{100}$Sn. We show that in $N=Z$ systems isovector and isoscalar proton-neutron pairing correlations always coexist.