Microscopic calculations of the background below giant resonances

Using a microscopic 1 particle-1 hole doorway model for nuclear excited states we show that the continuous forward angle energy spectra of medium energy (p,n)-reactions are mainly a result of direct one-step processes. The model is applied to the reactions 48Ca (p,n) at 160 MeV and to 90Zr (p,n) at 200 MeV incident energy. In case of 90Zr (p,n) we find that a large fraction of Gamow-Teller strength is located in the high excitation energy region 15 <= Esub(x) <= 50 MeV. There are indications that the transition strength of the spin-flip giant dipole (ΔL=1, ΔS=1, ΔT=1) resonance is quenched by roughly 50 %