Projectile Fragmentation of the Extremely Neutron-Rich NucleusLi11at 0.79 GeV/nucleon

Abstract

Projectile fragmentations of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^8{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ have been measured at 0.79 GeV/nucleon. Production cross sections and momentum distributions of the produced isotopes ($Z\ge 2$) are measured inclusively. Transverse-momentum distributions of ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ from the fragmentation of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ show two Gaussian components of different widths. The width of the wide component is consistent with the values observed in the fragmentation of stable nuclei, whereas the other component shows an extremely narrow width reflecting the weak binding of the two outer neutrons in the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ nucleus.