Role of direct mechanism in two-nucleon T=0 transfer reactions in light nuclei using the (Li-6, alpha) probe

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Zamora, J. C. ; Ferreira, J. L. ; Barioni, A. ; Cardozo, E. N. ; Abriola, D. ; Arazi, A. ; Assuncao, M. ; de Barbara, E. ; Cardona, M. A. ; Guimaraes, V ; Hojman, D. ; Marti, G., V ; Mendes, D. R. ; Pacheco, A. J. ; Pires, K. C. C. ; Ramos, D. ; Santos, O. C. B. ; Lubian, J.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW C; v. 106, n. 1, p. 14-pg., 2022-07-05.

Resumo

Background: Two-nucleon transfer reactions provide a unique tool to understand the correlation between nucleon pairs. Two-nucleon (pp, nn, and np) transfer reactions can occur via isoscalar (T = 0, S = 1) or isovector (T = 1, S = 0) processes. In particular, the isoscalar pair transfer can be induced by the (alpha, d) or (Li-6, alpha) probes. In the past, most of the isoscalar np-transfer studies were performed with the (alpha, d) reaction, but this probe is strongly momentum mismatched with respect to other two-nucleon transfer reactions. Purpose: We aim to investigate the interplay between direct and sequential reaction mechanisms from the analysis of experimental (Li-6, alpha) angular distributions in light targets. Method: Differential cross sections of (Li-6, alpha) reactions at a beam energy of 20 MeV were measured with C-12 and F-19 targets. The interplay between direct and sequential transfer mechanisms in the experimental angular distributions was investigated with coupled-reaction-channels calculations. Results: The experimental angular distributions of isoscalar np transfer were compared with theoretical calculations assuming a direct or a sequential reaction mechanism. Direct np-transfer calculations describe successfully most of the angular distributions. The sequential transfer mechanism is about two orders of magnitude smaller than the direct process. Conclusions: The present results suggest a significant np correlation in the C-12(Li-6, alpha)N-14(*) and F-19(Li-6, alpha)Ne-21(*) reactions. Despite the relatively low cross section for the reactions with the asymmetric F-19 target, the direct transfer mechanism remains dominant over the sequential process. Further studies including measurements with other asymmetric sd-shell nuclei will be required to fully understand the isoscalar and isovector np-transfer mechanism in this nuclear region. (AU)

• Processo FAPESP: 18/04965-4 - Estudo da estrutura e reações nucleares induzidas por feixes radioativos usando alvo ativo
• Beneficiário: Juan Carlos Zamora Cardona
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 19/07767-1 - Reações nucleares com núcleos fracamente ligados ou com estrutura de cluster, radioativos e estáveis
• Beneficiário: Leandro Romero Gasques
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 16/17612-7 - Dinâmica de sistemas de muitos corpos IV
• Beneficiário: Arnaldo Gammal
• Modalidade de apoio: Auxílio à Pesquisa - Temático