High spin resonances in 12C+12C scattering

Recent measurements of the excitation function for the reaction 12C[12C,12C(31-)] 12C(31-) from Ec.m. = 32 to 45 MeV revealed peaks at the centre-of mass energies Ec.m. = 32.5, 37.5 and 43 MeV. In the present study, detailed angular correlation measurements are performed suggesting that each of these energies correspond to a dominant angular momentum J=18, 20 and 22 (h/2π) respectively. Theory predicts that there are two main configurations of 24Mg which can sustain a value of J≥16 (h/2π). One is the six α-particle linear chain state, the other has a highly deformed 12C+12C structure (F1). The mutual 31- channel is considered to be associated with the Fl configuration in 24Mg, which according to theory, is able to sustain a maximum angular momentum value of J= 22 (h/2π). A further experiment was performed to extend the excitation function up to Ec.m.= 60 MeV to test for the termination of the mutual 31- band of resonances. Other open channels, the most important of which is the 12C(41+) single and mutual channels, were also investigated and an angular correlation measurement of a broad peak in the excitation function for the 12C[12C,12C(41+)]12Cg.s. channel at Ec.m.= 44 MeV was performed. Using the same extensive data set, an investigation was also conducted to observe the 12C[12C,16O*]8Be channel. Reconstruction of a number of 16O states formed from a triplet of 8Be fragments have been observed at 28, 31.5, and 35.5 MeV respectively. Preliminary analysis would suggest that these states form a 16O(6+, 8+, 10+) rotational band. However only spins for the 6+ and 8+ have been definitely determined in the present study. These states have been suggested by the author to be candidates for a four α-particle chain state. (author)