Sr87(t,p)reaction and the two-particle-one-hole states ofSr89

The ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}\mathrm{}(t,p)\mathrm{}{}_{}{}^{89}{}_{}{}^{}\mathrm{Sr}$ reaction has been studied at a bombarding energy of 20 MeV. The lowest states excited are basically of single particle character and the corresponding ($t,p$) differential cross sections contain a mixture of $L$ values. A comparison of these cross sections to distorted wave (DW) calculations yields qualitative information concerning configuration mixing in these states based both on the magnitudes as well as the shapes of the angular distributions. Analysis of the data is made partly by a comparison of DW calculations to the observed ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}\mathrm{}(t,p)\mathrm{}$ differential cross section and partly by comparing experimental angular distributions of the ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}\mathrm{}(t,p)\mathrm{}{}_{}{}^{90}{}_{}{}^{}\mathrm{Sr}$ reaction with those from ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}\mathrm{}(t,p)\mathrm{}$. The higher lying states observed in this experiment may be explained from the coupling of the $1g_{\frac{9}{2}}$ neutron hole to the multipole pairing phonons, represented by the low lying states of ${}_{}{}^{90}{}_{}{}^{}\mathrm{Sr}$.