SIMPLE REACTION STRUCTURES IN A "COMPLICATED" KINEMATIC RANGE

The energy range between 500 and 1000 MeV is usually considered a "complicated" one for elastic proton-proton scattering in which there is no simple description. It is shown that in that energy range, for much of the angular range, two simple features of the magnitudes and relative phases of the invariant amplitudes in the planar transverse frame give a good approximation of the observed data on unpolarized cross section as well as all the various polarization measurements. The features appear to be particularly pronounced at the larger scattering angles and higher energies, thus suggesting a connection with the small distance part of the internucleon force which thus may shed light on the validity of various quark models. Similar regularities also appear in a similar energy and angular range for pion-nucleon scattering. A simple way is presented on a quark level to summarize these regularities.