We investigate the fragmentation mechanism reflecting the cluster structure of the ${}^{19}\mathrm{B}$ nucleus. We perform antisymmetrized molecular dynamics (AMD) calculations of ${}^{19}\mathrm{B}{+}^{14}\mathrm{N}$ and ${}^{13}\mathrm{B}{+}^{14}\mathrm{N}$ reactions, and compare ${}^{19}\mathrm{B}$ fragmentation with ${}^{13}\mathrm{B}$ fragmentation. The neutron drip-line nucleus ${}^{19}\mathrm{B}$ has been predicted to have a well-developed cluster structure in its ground state while the neutron closed-shell nucleus ${}^{13}\mathrm{B}$ has no clustering features in its structure. The clustering structure of ${}^{19}\mathrm{B}$ is reflected in its fragmentation as the dynamical cluster breakup into He and Li isotopes, depending on the incident energy. In the low-incident-energy region around 30 MeV/nucleon, dynamical cluster breakup of ${}^{19}\mathrm{B}$ occurs and brings about an abundance of He and Li isotopes in ${}^{19}\mathrm{B}$ fragmentation compared with those in ${}^{13}\mathrm{B}$ fragmentation. In the high-incident-energy region above 50 MeV/nucleon, dynamical cluster breakup of ${}^{19}\mathrm{B}$ hardly occurs and the cluster structure of the ${}^{19}\mathrm{B}$ nucleus is not reflected in its fragmentation. We suggest here the coincident experiment between He and Li isotopes as an experimental way to confirm whether the ${}^{19}\mathrm{B}$ nucleus has a cluster structure in its ground state or not.

• Received 7 September 2000

DOI:https://doi.org/10.1103/PhysRevC.63.034615