Electromagnetic dissociation of 60 a (GeVO)-O-16 in emulsion

The electromagnetic dissociations (EDs) of 60 A (GeVO)-O-16 in nuclear emul sion is investigated with high statistics for the first time. It is found t hat the interaction cross section for EDs increases with increasing beam en ergy, and the charge distribution of projectile fragments is the same as th e results at 200 A GeV, but the production probability of projectile fragme nts with charge 3 less than or equal to Z less than or equal to 5 is smalle r than that of the results at 200 A GeV. These results can be explained by use of the Weizscker-Williams method for calculating the EDs contributions. The percentage abundances of various decay modes for EDs at 60 A GeV is th e same as the results at 200 A GeV,but different from the results at 14.6 A GeV. The EDs of 60 A GeV O-16 is mainly caused by the giant dipole and qua drupole resonance of E1 and E2 and by the quasi deuteron effect, which can be qualitatively explained by the multiplicity distribution of projectile f ragmentation proton in EDs. The multiplicity distribution of a fragments in EDs and nuclear events have different functional forms. This difference ma y be a consequence of the different reaction mechanisms involved in EDs and nuclear events.