Polarization in theY89(p, p)Y89Reaction near thed32Isobaric Spin Doublet

The polarization of protons elastically scattered from ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ has been observed at a laboratory angle of 125° in the incident energy range 7.1-7.6 MeV. Differential cross sections were also measured in this energy range at laboratory angles of 90°, 125°, 150°, and 170°. The isobaric analogs of the $2^{-}$ and $1^{-}$ states at 2.48 and 2.63 MeV in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Y}$ were observed at resonance energies of 7.29 and 7.46 MeV. Polarization angular distributions were taken at 7.28 and 7.45 MeV. An optical-model-plus-resonance analysis of all the data showed that these analog states could be described by a $d_{\frac{3}{2}}$ state coupling with the ${\mathrm{½}}^{-}$ target spin. The amount of $d_{\frac{5}{2}}$ and $s_{\frac{1}{2}}$ admixture possible in the $2^{-}$ and $1^{-}$ states, respectively, was shown to be quite small. This indicates that there is very little mixing between the various $2^{-}$ and $1^{-}$ single-particle configurations in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Y}$.