An anomaly, apparently a final-state spin dependence, has been observed in proton inelastic scattering from ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, and ${}_{}{}^{67}{}_{}{}^{}\mathrm{Zn}$. The excited-core model of inelastic scattering cannot produce such an effect. Indeed, no current theory of inelastic scattering based on the distorted-wave Born approximation can even qualitatively predict such an effect.

• Received 23 December 1968

DOI:https://doi.org/10.1103/PhysRevLett.22.1005