MULTIFRAGMENTATION OF THE REMNANT PRODUCED IN THE REACTION OF 1A GEV GOLD WITH CARBON

A high-statistics exclusive study of the multifragmentation of 1A GeV gold on carbon has been performed. Particles with Z less than or equal to 2 show evidence of emission in a first prompt stage as well as in a second equilibrium stage whereas fragments with Z greater than or eq ual to 3 appear to be emitted essentially only in the second stage. Tw o methods for the separation of the Z less than or equal to 2 particle s into the two stages are given and they are ill agreement. The yields for each stage are determined as a function of the event charged part icle multiplicity m. The mass, nuclear charge, excitation energy per n ucleon, and temperature of the remnant left after the first stage and their fluctuations have been determined as a function of m. The expans ion of the remnant to fragment freeze-out is examined. The freeze-out temperature is determined from double isotope ratios as a function of, li and isentropic trajectories are obtained in the temperature-density plane. The caloric curve shows a monotonic increase with excitation e nergy. Some of the energy is in the form of radial flow. Overall, the results are consistent with a previous statistical analysis of the dat a which suggests that, over a certain range of excitation energies, mu ltifragmentation involves a continuous phase transition.