Four α-particles as a final state of 16O* Quasi Projectile decay

Abstract

Four α-particles as a final state of ¹⁶O^* quasi-projectile decayproduced in peripheral ¹⁶O+¹²C reactions at 130 MeV is thoroughly studied. The differentdecay channels leading to the four α-particles final state are reconstructed by carrying out an event-by-event analysis of α correlations in the population of intermediate ⁸Be and ¹²C. Although small, a non negligible contribution due to ⁸Be_gs evaporation is found.A comparison between predictions of an accurate Hauser-Feshbach decay code and branching ratios of the different decay channels is performed. Significant deviations are observed, among these the Hoyle state population which is considerably lower than the one predicted according to the statistical model, thus suggesting possible structure effects in the Coulomb barrier and/or in the transmission coefficients.