The symmetric ${}^{10}\mathrm{B}+{}^{10}\mathrm{B}$ reaction provides a unique opportunity to populate high-energy, high-spin states in the mirror pairs ${}^{10}\mathrm{Be}\text{−}{}^{10}\mathrm{C}$, ${}^{11}\mathrm{B}\text{−}{}^{11}\mathrm{C}$, and ${}^9\mathrm{Be}\text{−}{}^9\mathrm{B}$. Excitation spectra for these systems have been measured and mirror analog states identified, enabling a systematic comparison of their level energies. We find that states in compact shell-model configurations (e.g., members of ground-state rotational bands) show very small mirror energy differences (consistent with standard Coulomb displacement energies), whereas spatially extended clusterlike states exhibit significantly reduced energy gaps consistent with the Thomas-Ehrman shift. In the ${}^{10}\mathrm{Be}\text{−}{}^{10}\mathrm{C}$ pair, a previously unreported level at $E_x=9.24\mathrm{MeV}$ in ${}^{10}\mathrm{C}$ is observed, which we propose as the isospin analog of the 9.56 MeV $2^{+}$ state in ${}^{10}\mathrm{Be}$. In the ${}^{11}\mathrm{B}\text{−}{}^{11}\mathrm{C}$ pair, we report a high-lying state at $E_x=10.69\mathrm{MeV}$ in ${}^{11}\mathrm{C}$, mirroring the 11.21-MeV level in ${}^{11}\mathrm{B}$ which was populated via one-nucleon transfer for the first time. Finally, the observed ${}^9\mathrm{Be}\text{−}{}^9\mathrm{B}$ mirrors show nearly identical excitation spectra; in particular, strongly populated states follow a $J(J+1)$ energy trend, highest of which are consistent with their assignment as the $9/2^{-}$ members of the ground-state rotational band. These findings highlight the interplay of Coulomb and structural effects in mirror nuclei and extend the known level schemes of the nuclei in question.

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• Cluster models
• Coulomb energies & analogue states
• Energy levels
• High spin states
• Nuclear reactions
• Nuclear structure & decays
• Shell model
• Transfer reactions
• 6 ≤ A ≤ 19