The breakup of $E/A=50$ MeV ${}^{12}\mathrm{Be}$ fragments following inelastic scattering off of hydrogen and carbon target nuclei has been studied. The breakup channels $\alpha +$${}^8\mathrm{He}$, ${}^6\mathrm{He}$$+$${}^6\mathrm{He}$, $t+$${}^9\mathrm{Li}$, and $p+$${}^{11}\mathrm{Li}$ were observed. Two doublets at excitation energies of 12.8 and 15.5 MeV were found for the $\alpha +$${}^8\mathrm{He}$ channel. A low-energy shoulder in the excitation-energy spectra at 10.2 MeV indicates one or more additional states. This work could not confirm the presence of ${}^6\mathrm{He}$$\text{−}$${}^6\mathrm{He}$ rotational structure reported by Freer et al. [Phys. Rev. C 63, 034301 (2001)], although possible peaks at excitation energies of 13.5 and 14.5 MeV were found for ${}^6\mathrm{He}$$+$${}^6\mathrm{He}$ decay. Significant structure is observed in the excitation-energy spectrum for $p+$${}^{11}\mathrm{Li}$ at 25–30 MeV which maybe associated with $T=3$ analog states.

• Received 22 June 2007

DOI:https://doi.org/10.1103/PhysRevC.76.064313