Fragment distributions for highly charged systems

Charge and transverse energy distributions for intermediate mass fragments have been extracted for central ⁸⁴Kr+¹⁹⁷Au collisions at E/A=35-400 MeV. The slopes of the measured fragment charge distributions decrease monotonically with incident energy, consistent with the expectations for highly charged systems, but not with recent critical exponent analyses. Statistical model calculations, which reproduce the experimental trends, suggest that post-breakup fragment secondary decays alter significantly the observed charge distributions. Radial expansion velocities extracted from these calculations follow the systematics of Au+Au collisions.