Inelastic pion scattering from 12C

Differential cross sections for inelastic pion scattering from 12C at incident energies of 100 to 291 MeV and momentum transfers to approx. =300 MeV/c have been measured and are used to investigate the understanding of the pion-nucleus interaction. Angular distributions and excitation functions are presented for many of the bound states, including the 4.44-MeV (2+,0), 7.66-MeV (0+,0), 9.64-MeV (3-,0), 12.71-MeV/15.11-MeV (1+;0,1) doublet, 16.11-MeV (2+,1) and 19-MeV (4-;0,1) doublet. Distorted-wave, impulse-approximation calculations using both macroscopic and microscopic descriptions of the nuclear wave functions deduced from electron and proton scattering data and straightforward configuration-space calculations are obtained for pion energies near the Δ33 resonance if adequate consideration is given to kinematics. Of particular interest was the observation of an anomalous excitation function for the T = 1 member of the 1+ doublet and the observation of dramatic π+/π- asymmetries near 19-MeV excitation due to isospin mixing in the 4--doublet