Excitation of isobaric analog states from (p, n) and (3He, t) charge-exchange reactions within the G-matrix folding method

Differential cross sections of (p, n) and (He-3, t) charge-exchange reactions leading to the excitation of the isobaric analog state (IAS) of the target nucleus are calculated with the distorted wave Born approximation. The G-matrix double-folding method is employed to determine the nucleus-nucleus optical potential within the framework of the Lane model. G matrices are obtained from a Brueckner-Hartree-Fock calculation using the Argonne Av18 nucleon-nucleon potential. Target densities have been taken from Skyrme-Hartree-Fock calculations which predict values for the neutron skin thickness of heavy nuclei compatible with current existing data. Calculations are compared with experimental data of the reactions (p, n)IAS on C-14 at E-lab = 135 MeV and Ca-48 at E-lab = 134 MeV and E-lab = 160 MeV, and (He-3, t)IAS on Ni-58, Zr-90, and Pb-208 at E-lab = 420 MeV. Experimental results are well described without the necessity of any rescaling of the strength of the optical potential. A clear improvement in the description of the differential cross sections for the (He-3, t)IAS reactions on Ni-58 and Zr-90 targets is found when the neutron excess density is used to determine the transition densities. Our results show that the density and isospin dependences of the G matrices play a non-negligible role in the description of the experimental data.