Impact parameter expansion of pi N scattering amplitudes at intermediate energies

Impact parameter transforms of isospin even no-flip pi N-amplitudes and of the overlap function are calculated from the new CERN phase shifts. The results are compared with different models. The approximate equality of the partial wave and the impact transform for bq=(l+1/2) is valid for small l and not for large l as frequently assumed. The 'optical potential' has a repulsive core in the real part and rather flat tails beyond 0.5 fermi in the real and imaginary parts. (40 refs).