By using the CHIMERA detector, we have measured the gamma-ray and alpha decay width of excited C-12 states important for the carbon production inastrophysical environments. For the first time, we directly observed the gamma-ray decayof the 9.64 MeV level. A gamma-ray decay width larger than previous observations wasobserved for the Hoyle state. In order to explain this enhanced yield we investigatedon the recently proposed population of an Efimov state at 7.458 MeV. The decaycharacteristics of such level are inferred
