Scattering of 400 MeV polarized protons from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ to the $0^{\mathrm{-}}$;T=0 state at 10.957 MeV has been studied from 3° to 14° in the laboratory. Measured values of cross section and analyzing power are compared with relativistic and nonrelativistic calculations. It is found that interference from a two-step excitation through the $3^{\mathrm{-}}$ state at 6.130 MeV is required in order to reproduce the large negative values of analyzing power observed at low momentum transfer.

• Received 15 April 1991

DOI:https://doi.org/10.1103/PhysRevC.44.1077