Cross-section and analyzing-power data are presented for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p,p^{\prime }){}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ reaction at bombarding energies of 155 and 200 MeV. Comparisons are made with the systematics of data from other energies. Distorted-wave impulse-approximation calculations for the "pion-like" $1^{+}$, $T=1\mathrm{}$ transition to the 15.11-MeV state are successful for $q<\mathrm{}280\mathrm{}$ MeV/c, but are substantially smaller than the data at larger momentum transfers. The implications of the data regarding precritical behavior associated with the pion-condensation threshold are discussed.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p,p^{\prime })$, $E=155\mathrm{}$ MeV, measured $\sigma (E,\theta )$; $E=200\mathrm{}$ MeV, measured $\sigma (E,\theta )$, $A_y\left(\theta \right)$; $\theta =6\mathrm{}-50°$, $\Delta \theta =2\mathrm{}-3°$, $E_x=11\mathrm{}-17$ MeV. DWIA analysis. Precritical phenomena near pion-condensation threshhold.

• Received 2 September 1980

DOI:https://doi.org/10.1103/PhysRevC.23.1858