Enhanced fragment emission in the interaction of 18.5 GeVC12ions with complex nuclei

Cross sections for the formation of seven fragments ranging from ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ to ${}_{}{}^{52}{}_{}{}^{}\mathrm{Mn}$ in the interaction of 18.5 GeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ions and 400 GeV protons with Cu, Ag, Gd, Ta, Au, and U have been measured. After correction for the difference in bombarding energy, the results were used to test the factorization hypothesis. Enhanced fragment emission in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ reactions was observed for all targets excepting copper. The magnitude of the enhancement and its dependence on target and product $A$ are described. The variation of fragment yields with target $A$ is examined. The neutron excess products obey modified $\mathrm{Qgg}$ systematics while the neutron deficient ones do not. The implications of these results for the reaction mechanism are considered.