Reexamination of the excited states ofC12

Abstract

An analysis of the $^{12}\mathrm{C}$($^{12}\mathrm{C}$,$3\ensuremath{\alpha}$)$^{12}\mathrm{C}$ reaction was made at beam energies between 82 and 106 MeV. Decays to both the ground state and the excited states of $^{8}\mathrm{Be}$ were isolated, allowing states of different characters to be identified. In particular, evidence was found for a previously observed state at 11.16 MeV. An analysis of the angular distributions of the unnatural parity states at 11.83 and 13.35 MeV, previously assigned ${J}^{\ensuremath{\pi}}={2}^{\ensuremath{-}}$, calls into question the validity of these assignments, suggesting that at least one of the states may correspond to ${J}^{\ensuremath{\pi}}={4}^{\ensuremath{-}}$. Evidence is also found for ${1}^{\ensuremath{-}}$ and ${3}^{\ensuremath{-}}$ strengths associated with broad states between 11 and 14 MeV.