β-decay half-lives at finite temperatures for N=82 isotones

Using the finite temperature quasi-particle random phase approximation (FTQRPA) on the basis of finite temperature Skyrme-Hartree-Fock + BCS method, we study $\beta^-$-decay half-lives for even-even neutron magic nuclei with N=82 in a finite temperature environment. We find that the $\beta^-$-decay half-life first decreases as the temperature increases for all the nuclei we study, although the thermal effect is found to be small at temperatures relevant to r-process nucleosynthesis. Our calculations indicate that the half-life begins to increase at high temperatures for open shell nuclei. We discuss this behavior in connection to the pairing phase transition.