Gamow-Teller transitions at finite temperatures in the extended quasiparticle random phase approximation

Gamow-Teller single β decay transitions (ΔJ=1, Δπ=0, ΔT_z=±1), at finite temperatures and between states of even-even and odd-odd mass nuclei, are calculated in the framework of the extended quasiparticle random phase approximation. Finite temperature blocking effects and particle-particle interactions are discussed in connection with the fragmentation of strength. It is shown that the inclusion of scattering terms, both in the phonons and in the transition operator, is needed to achieve the complete conservation of the transition strength. The calculations were performed in the mass region A=106 and for temperatures lower than the critical value T_c associated to the collapse of the pairing gaps (T_c≅0.7 MeV).