Dynamics of the Multifragmentation of 1<i>A</i>GeV Gold on Carbon

Abstract

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 $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ and some $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$ 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.