Alpha Cluster Structure in 13C and 16,17O, M. R. D. Rodrigues, T. Borello-Lewin, H. Miyake, L. B. Horodynski-Matsushigue, J. L. M. Duarte, C. L. Rodrigues, M. A. Souza, Instituto de Física, Universidade de São Paulo Caixa Postal 66318, CEP 05389-970, São Paulo, SP, Brazil, A. Cunsolo, F. Cappuzzello, A. Foti, M. Cavallaro, INFN - Laboratori Nazionali del Sud via S. Sofia 62, 95125 Catania, Italy, and G. M. Ukita, Faculdade de Psicologia, Universidade de Santo Amaro Rua Professor Eneas da Siqueira Neto, 340, CEP 04829-300, São Paulo, SP, Brazil − The alpha cluster phenomenon in the light nuclei structure has been the subject of a longtime investigation since the proposal of the Ikeda diagrams[1]. The mechanism of the cluster formation is still not completely understood. Furthermore, the fact that the clusters have a fairly rigid crystal-like or a gas-like structure remains an open question[2-4]. The interpretation of the Hoyle state as an α condensate brought a renewed interest to this subject. The research focus was extended to resonances analogous to the Hoyle state, not only for the (xα) nuclei, but also for the (xα+n) ones[5-8]. In this context the study of the experimental evolution of the α-cluster phenomenon in (xα) and (xα+n) nuclei through (6Li,d) transfer reactions is the main subject of the present work[9]. The 12,13C(6Li,d)16,17O and 9Be(6Li,d)13C reactions were recently measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion  detection technique. Resonant states above the alpha threshold were measured and an energy resolution of 30-40 keV allows to define unresolved states. The absolute cross sections and the respective deuteron angular distributions were determined in a range of 4-30 degree in the center of mass system and up to 17 MeV excitation energy. The analysis is in progress.

[1] K. Ikeda, N. Takigawa, and H. Horiuchi, Prog. Theor. Phys. Suppl. E68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978).

[2] Y. Funaki et al., Phys. Rev. C 82, 024312 (2010).

[3] S. Okubo and Y. Hirabayashi, Phys. Lett. B681, 127-131 (2010).

[4] M. Itoh et al., Phys. Rev. C 84, 054308 (2011).