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

Abstract

A comparative study of the fragmentation of $^{4}\mathrm{He}$, $^{12}\mathrm{C}$, $^{14}\mathrm{N}$, and $^{16}\mathrm{O}$ nuclei, $E=2.1$ GeV/nucleon, has been made by using nuclear emulsion detectors. The interaction mean-free paths (cm) for these nuclei in emulsion are 21.8 \ifmmode\pm\else\textpm\fi{} 0.7, 13.8 \ifmmode\pm\else\textpm\fi{} 0.5, 13.1 \ifmmode\pm\else\textpm\fi{} 0.5, and 13.0 \ifmmode\pm\else\textpm\fi{} 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 $Z=1 \mathrm{and} 2$ 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.NUCLEAR REACTIONS Emulsion exp., $^{4}\mathrm{He}$, $^{12}\mathrm{C}$, $^{14}\mathrm{N}$, and $^{16}\mathrm{O}$ at 2.1 GeV/A; measured mean-free-path lengths; projectile fragmentation reactions; angular, number, and charge multiplicity distributions. Optical and geometrical models; limiting fragmentation.