Evidence for high excitation energy resonances in the 7 alpha disassembly of ${}^{28}$Si

The excitation function for the 7 alpha de-excitation of ${}^{28}$Si nuclei excited to high excitation energies in the collisions of 35 MeV/nucleon ${}^{28}$Si with ${}^{12}$C reveals resonance structures that may indicate the population of high spin toroidal isomers such as those predicted by a number of recent theoretical calculations. This interpretation is supported by extended theoretical analyses.