SENSITIVITY OF PP-BREMSSTRAHLUNG TO MESON-EXCHANGE CURRENTS

We present pp-bremsstrahlung cross section calculations at the pi-prod uction threshold to search for kinematics that best differentiate mode l-dependent descriptions of the NN t-matrix and accentuate the contrib utions of isoscalar meson-exchange currents. Existing optimization pro cedures are shown to be completely unreliable due to the neglect of me son-exchange currents and phase space variations. We show that phase-s pace hides the most important differences in model t-matrices, but tha t improved data will be critical to further investigations of exchange currents.