High-Spin-State Spectroscopy with the ReactionSr88(ppol,π−)Zr89

The pronounced selectivity of near-threshold ($p$, ${\pi }^{-}$) reactions for high-spin two-particle, one-hole states is exploited, in the first spectroscopic application of a ($p$, $\pi$) reaction, to identify previously unknown $\frac{25}{2^{+}}$ and $\frac{21}{2^{+}}$ ${\left(g_{\frac{9}{2}}\right)}^3$ states in ${}_{}{}^{89}{}_{}{}^{}\mathrm{Zr}$. Relative cross sections for the two transitions are well reproduced by simple model calculations. The analyzing power for the $\frac{25}{2^{+}}$ state is markedly similar to previous ($p_{\mathrm{pol}}$, ${\pi }^{-}$) results for two-particle, one-hole stretched states in lighter nuclei.