Role of 8Be heavy stripping mechanism in the α + 12C inelastic scattering to the near-3α-threshold states in 12C

The angular distributions of α + 12C elastic and inelastic (to the 4.44 MeV, 2+; 7.65MeV, 0+; and 9.64MeV, 3− states) scattering at 110 MeV are characterized by pronounced enhancement and strong oscillations at large angles. We performed calculations of the differential cross sections of these reactions assuming a potential scattering in the forward hemisphere and the direct transfer of 8Be cluster θc.m. > 90°. We showed that the α + 8Be cluster configuration with relative angular momentum L = 0 dominates in the Hoyle state being 4.4 times larger than that in the ground state. This result also contributes to the verification of αBEC hypothesis and is consistent with the conjecture of a dilute 3α structure of the Hoyle state. In the 9.64 MeV, 3− state, a positive interference of all allowed α + 8Be configurations with a dominance of the p-orbital (49%) α-8Be relative motion is found. This finding manifests the exotic 3α, but hardly condensed structure of the 9.64-MeV 3− state in 12C.