Gamow-Teller studies within the Subtracted Second RPA

Recent applications of the subtracted second random-phase approximation (SSRPA), based on Skyrme functionals, to the study of Gamow-Teller excitations and beta-decay are presented and discussed. The comparison with the conventional random-phase approximation (RPA) results and experimental data is also discussed. It is found that the amount of Gamow-Teller strength obtained in SSRPA is much lower than the RPA one, and it agrees better with experimental data. The inclusion of two-particle-two-hole configurations is responsible for this quenching, avoiding thus the use of any “ad-hoc” quenching factors normally adopted in this kind of studies. This result may have implications for the computation of nuclear matrix elements in the same framework for neutrinoless double-beta decay.