Role of T=0 pairing in Gamow-Teller states in N=Z nuclei

TL;DR

This study investigates how T=0 pairing interactions influence Gamow-Teller states in N=Z nuclei, revealing that T=0 pairing enhances low-energy GT strength and explains observed two-peaked structures in reactions.

Contribution

It introduces the role of T=0 pairing in GT states within N=Z nuclei using HFB+QRPA with Skyrme interactions, highlighting its impact on GT strength and structure.

Findings

T=0 pairing enhances low-energy GT strength.

Two-peaked structure in $^{56}$Ni explained by T=0 pairing.

T=0 pairing works cooperatively with T=1 pairing.

Abstract

Gamow-Teller (GT) states in N=Z nuclei with the mass number A from 48 to 64 are studied by using Hartree-Fock-Bogoliubov + quasi-particle random phase approximation (HFB+QRPA) with Skyrme interactions. The isoscalar spin-triplet (T=0,S=1) pairing interaction is taken into account in QRPA calculations. It is found in the context of SU(4) symmetry in the spin-isospin space that the GT strength of lower energy excitations is largely enhanced by the T=0 pairing interaction which works cooperatively with the T=1 pairing interaction in the ground state. A two-peaked structure observed recently in $(p,n)$ reaction on $^{56}$Ni can be considered as a manifestation of the role of T=0 pairing in the GT collective states.