Spin-isospin excitations in the direction of ? plus decay for 80Zn and 126Ru at finite temperature

We investigate the Gamow-Teller (GT) and spin-dipole (SD) transitions in the direction of 0+ decay for neutron-rich N = 50 nucleus 80Zn and N = 82 nucleus 126Ru, which are important for deleptonization phase in core-collapse supernova, at T = 0, 1, 2 MeV with finite-temperature proton-neutron relativistic (quasiparticle) random-phase approximation. At zero temperature, the GT+ transitions for 80Zn and 126Ru are almost completely Pauli blocked because one more extra shell is occupied for neutrons than that for protons. With increasing temperature to even 2 MeV, the thermal excitation still cannot open up GT+ transitions with strong strength. The SD+ transitions in 80Zn are mildly affected by temperature, which means the experimental data measured at the laboratory can provide useful information for transitions in an astrophysical environment. However, for SD+ transitions in 126Ru, the transition energies have a decrease of about 2 MeV from zero temperature to T = 1 MeV due to the collapse of pairing gap of transition orbitals. The total strength in T+ channel decreases with increasing temperature for both GT and SD transitions, due to the suppression of their transition strength induced by temperature effects.

Automated summary

We investigated the GT and SD transitions in the 0+ decay direction of neutron-rich N = 50 nucleus 80Zn and N = 82 nucleus 126Ru at different temperatures using finite-temperature proton-neutron relativistic random-phase approximation. The GT+ transitions in 80Zn and 126Ru are almost completely Pauli blocked at zero temperature due to the occupation of an extra shell by neutrons. Even with increasing temperature, the thermal excitation cannot open up strong GT+ transitions. The SD+ transitions in 80Zn are mildly affected by temperature, while in 126Ru, the transition energies decrease by about 2 MeV at T = 1 MeV due to the collapse of the pairing gap.