Dynamics of the Multifragmentation of 1A GeV Gold on Carbon

An exclusive study of the interaction of 1A GeV Au with C shows a separability into two stages: a prompt stage involving emission of most $Z=1\mathrm{}$ and some $Z=2\mathrm{}$ particles and a second stage involving the decay of an equilibrated remnant, which typically undergoes multifragmentation. The mean mass, charge, excitation energy, and the initial temperature $T_i$ of the remnant have been determined as a function of the total charge multiplicity, $m$, as has the freeze-out temperature $T_f$. Both $T_i$ and $T_f$ increase linearly with $m$ and their values at the critical point have been determined. $T_f$ rises monotonically with excitation energy as expected for a continuous phase transition.