"Stretched" states excited in theCa48(p,n)Sc48reaction at 160 MeV

Charge-exchange reactions on $N>Z$ targets can excite unnatural-parity states of stretched configurations which are not analogs of states excited in ($e,e^{\prime }$) and ($p,p^{\prime }$) reactions. This "new" class of stretched states is based on a proton-particle, neutron-hole configuration with both the particle and the hole in the same shell. A state of this type ($0\hslash \omega$) with a major configuration of ${(\pi f_{\frac{7}{2}},\nu f_{\frac{7}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{7^{+}}$ is observed to be strongly excited in the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}\mathrm{}(p,n)\mathrm{}{}_{}{}^{48}{}_{}{}^{}\mathrm{Sc}$ reaction at 160 MeV; however, no evidence is found for $1\hslash \omega$ stretched states based on ${(\pi g_{\frac{9}{2}},\nu f_{\frac{7}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{8^{-}}$ or ${(\pi f_{\frac{7}{2}},\nu d_{\frac{5}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{6^{-}}$ configurations.