Fragmentation ofHe4,C12,N14, andO16nuclei in nuclear emulsion at 2.1 GeV/nucleon

A comparative study of the fragmentation of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ nuclei, $E=2.1\mathrm{}$ GeV/nucleon, has been made by using nuclear emulsion detectors. The interaction mean-free paths (cm) for these nuclei in emulsion are 21.8 ± 0.7, 13.8 ± 0.5, 13.1 ± 0.5, and 13.0 ± 0.5, respectively. These data are discussed in terms of optical models and geometrical theories. Fragmentation reactions initiated by ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectiles that exhibit no target excitation, i.e., that possess no low energy particle emission. are selected for special study of projectile fragmentation. The projected angular distributions of $Z=1\mathrm{} \mathrm{and} 2$ secondaries from these interactions are reported, as are the prong-number and charge-multiplicity distributions. The angular distributions are independent of the projectile and exhibit features of limiting fragmentation.