Gamow-Teller excitations in the Subtracted Second RPA approach

Abstract

The charge-exchange subtracted second random-phase approximation, based on Skyrme functionals, is employed to investigate the Gamow-Teller resonances in several nuclei, located in different regions of the nuclear chart. The amount of Gamow-Teller strength is considerably smaller than in other energy-density-functional based calculations and agrees better with the experimental data. These important results, obtained without any ad hoc quenching factors, are due to the inclusion of two-particle–two-hole configurations. Their density progressively increases with excitation energy, leading to a long high-energy tail in the spectrum. This result may have implications for the computation of nuclear matrix elements for neutrinoless double-beta decay in the same framework.