The excitation functions for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${\pi }^{\pm }$,$\pi N$)${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ reactions have been established for 40- to 600-MeV ${\pi }^{-}$ and 50- to 520-MeV ${\pi }^{+}$. These excitation functions are dominated by the (3,3) pion-nucleon resonance but show an upward energy shift in the resonance peak for ${\pi }^{-}$ (to about 190 MeV) and a downward shift for ${\pi }^{+}$ (to about 160 MeV). The $\frac{\sigma \left({\pi }^{-}\right)}{\sigma \left({\pi }^{+}\right)}$ ratio at 180 MeV is 1.59±0.07. The results are compared with theoretical calculations based on a semiclassical transport model including nucleon charge exchange and an intranuclear cascade model.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${\pi }^{\pm }$,$\pi N$)${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$, excitation functions, $E{\pi }^{+}=50-520\mathrm{}$ MeV, $E{\pi }^{-}=40-600\mathrm{}$ MeV. Plastic scintillator targets, measured ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ by ${\beta }^{+}-\gamma$ coincidences. Compared with semiclassical transport and intranuclear cascade calculations.

• Received 27 March 1979

DOI:https://doi.org/10.1103/PhysRevC.20.1844