The gamma decay of the Hoyle and higher excitation energy states of C-12

The 0(2)(+) Hoyle state and few other excited levels of C-12 are fundamental for the production of carbon in the universe. In particular, the gamma decay branching ratio is of utmost importance, being the only way to produce a carbon at the ground state. For the purpose to precisely investigate the decay mechanism of such states we conducted an experiment, at Laboratori Nazionali del Sud-Istituto Nazionale di Fisica Nucleare (INFN-LNS), using the reaction alpha + C-12 at 64 MeV. We used the 4 pi CHIMERA detector to detect both alpha and gamma C-12 decay channels. Details of the experiment and preliminary results are discussed in the paper.