Efimov States From Triple α Resonances

The Efimov trimers in excited  12 C nuclei, which no observation exists yet, are discussed by means of analyzing the experimental data of  70(64) Zn( 64 Ni) + 70(64) Zn( 64 Ni )reactions at beam energy of E/A=35 MeV/nucleon. In heavy ion collisions, the  α s interact with each other and can form complex systems such as  8 Be and  12 C. For the 3 α  systems, multi resonance processes give rise to excited levels of  12 C. The interaction between any two of the 3 α  particles provides events with one, two or three  8 Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events of three couple  α relative energies consistent with the ground state of  8 Be are observed with the decreasing of the instrumental error at the reconstructed 7.458 MeV excitation energy of  12 C, which was suggested as the (Thomas) Efimov state.