FRAGMENTATION AND MULTIFRAGMENTATION OF 10.6A GEV GOLD NUCLEI

Interactions of 10.6A GeV gold nuclei have been studied in nuclear emulsions. In a minimum bias sample of 1100 interactions, 4730 helium nuclei and 2102 heavy nuclei were emitted as fragments of the incident gold projectiles. The emission angles of these fragments have been measured and pseudorapidity distributions constructed. The multiplicity distributions have been considered separately for the light and heavy target nuclei in the emulsions and found to be relatively independent of the nature of the target, when studied in terms of the total charge remaining bound in the multiply charged fragments. These distributions have been compared with those reported by experiments that studied the multifragmentation of 0.6 and 1.0A GeV gold nuclei, and show relatively small but statistically significant differences that may be attributed to the differing energies or, possibly, to detection biases in the low energy data. We have also looked for evidence of phase changes in the description of multifragmentation and compared our conclusions with those of a study of 1.0A GeV gold nuclei interacting in a carbon target. We see evidence of behavior that is similar, but not entirely consistent, with that reported at the lower energy. Whether this is evidence for a true phase change in the state of the nuclear matter remains an open question.