Charge-exchange spin monopole modes

Abstract

Using the self-consistent Hartree-Fock plus Tamm-Dancoff approximation with Skyrme interactions, the response of some $\ensuremath{\beta}$ stable closed-shell nuclei to charge-exchange ${(t}_{\ifmmode\pm\else\textpm\fi{}})$ spin monopole fields is estimated in the coordinate space. Both the isoscalar and isovector spin-correlation are included simultaneously. The excitation energy of ${t}_{+}$ giant resonance decreases considerably as the neutron excess (and consequently the nuclear mass number) increases, while that of ${t}_{\ensuremath{-}}$ giant resonance remains nearly constant. We have tried to separate out the Gamow-Teller strength from the present charge-exchange spin monopole strength, both of which have the same quantum numbers, ${J}^{\ensuremath{\pi}}{=1}^{+}.$