High-Resolution Proton Scattering onZr91and the Core-Excitation Model

Abstract

The reactions ${\mathrm{Zr}}^{90}(p,{p}^{\ensuremath{'}}){\mathrm{Zr}}^{90}$ and ${\mathrm{Zr}}^{91}(p,{p}^{\ensuremath{'}}){\mathrm{Zr}}^{91}$ have been studied with 12.0-MeV protons. Proton spectra were measured with a broad-range magnetic spectrograph at six reaction angles between 30\ifmmode^\circ\else\textdegree\fi{} and 90\ifmmode^\circ\else\textdegree\fi{}, sufficient to distinguish between $L=2$ and $L=3$ transitions. The ${\mathrm{Zr}}^{91}$ spectrum is interpreted in terms of ${d}_{\frac{5}{2}}$, ${s}_{\frac{1}{2}}$, ${d}_{\frac{3}{2}}$, and ${g}_{\frac{7}{2}}$ neutron states coupling to the low-lying states of the ${\mathrm{Zr}}^{90}$ core. The predictions of the core-excitation model are compared in detail with the data for the multiplets formed by the ${d}_{\frac{5}{2}}$ neutron coupling to the 2+ and 3- states in the ${\mathrm{Zr}}^{90}$ core.