HINTS OF A NEARSIDE NUCLEAR RAINBOW IN PION-SCATTERING FROM PB-208 AT291-MEV

The scattering of pi +/- + Pb-208 at 291 MeV can be described by an op tical potential with a repulsive real part which is strong enough by i tself to sustain a nuclear rainbow in the nearside scattering. We exam ine this in detail, using a semiclassical analysis, and find that incl uding a physically realistic amount of absorption completely changes t he nature of the scattering so that the rainbow language is no longer appropriate. We compare the pion case with the scattering of light hea vy-ion systems which appear to suffer comparable absorption, yet for w hich the rainbow language remains significant and useful. We conclude that, in fact, the pion scattering is better characterized as strong a bsorption scattering than is the case for the heavy ions.