Electromagnetic dissociation for high-Z projectiles and at ultrarelativistic energies.

Experiments to determine the characteristics of electromagnetic dissociation (ED) has been extended to high projectile charge and ultrarelativistic energies using $^{139}\mathrm{La}$ and $^{16}\mathrm{O}$ projectiles on $^{197}\mathrm{Au}$ targets. The gross features are reproduced in a Weizs\"acker-Williams calculation but significant systematic deviations appear. The results are used as a guide in extending the calculations to the regime of energies and projectiles expected for planned heavy-ion colliders where Ed effects should comprise a major fraction of the total cross section.