Elastic scattering in the 12N+197Au system at Elab=70 MeV

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Magro, P. L. D. ; Guimaraes, V. ; Linares, R. ; Rangel, J. ; Zamora, J. C. ; Rogachev, G. V. ; Koshchiy, E. ; Bishop, J. ; Barbui, M. ; Parker, C. E. ; Roeder, B. ; Saastomoinen, A.

• Document type: Journal article
• Source: PHYSICAL REVIEW C; v. 111, n. 3, p. 9-pg., 2025-03-11.

Abstract

Background: Halo structure is an interesting exotic configuration developed in some light weakly bound nuclei, where a valence particle orbits a nuclear core. Signatures of halo structure can be observed in the angular distributions of the elastic scattering induced by these nuclei at energies around the Coulomb barrier. There are some well-studied reactions with neutron-rich halo nuclei, such as 6He and 11Li. However, the information is scarce on the proton-rich side. Recent works confirm the halo structure in the 8B nuclei but still lack more experimental studies for other proton-halo candidates, such as 12N and 17F. Purpose: In this work, we report experimental data for the elastic scattering of 12N on 197Au target at Elab = 70 MeV. The 12N is a proton-rich nucleus with proton separation energy Sp = 600 keV, which is higher than the 8B (Sp = 137 keV) and almost the same as the 17F (Sp = 601 keV). Methods: Data were obtained at the Cyclotron Institute of Texas A&M University where the 12N radioactive beam was produced by the momentum achromatic recoil spectrometer. The calculation of the optical model was used to fit the measured angular distribution for the elastic scattering and to obtain the reaction cross section QR. We also performed continuum discretized coupled-channel calculations to compare with the experimental data. Results: The angular distribution of the elastic cross sections exhibits a suppression of the Fresnel peak. From the fitting of the optical model, we obtain the total reaction cross section, QR = 1269 +/- 41 mb. The agreement between the CDCC calculation and the experimental elastic scattering data is limited and the breakdown does Conclusions: The resulting reduced reaction cross section QRed for 12N + 197Au is large and comparable to the one obtained for the 8B + 208Pb system. This suggests a strong decoupling of the valence proton from the core because of the low binding energy and a dynamic polarization effect. More research is required to estimate the contribution of core excitation. (AU)

• FAPESP's process: 19/08344-7 - Study of structure and nuclear reactions induced by exotic nuclei
• Grantee: Valdir Guimarães
• Support Opportunities: Regular Research Grants
• FAPESP's process: 24/02463-2 - Investigation of cluster structures in light nuclei
• Grantee: Valdir Guimarães
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/17612-7 - Dynamics of many-body systems IV
• Grantee: Arnaldo Gammal
• Support Opportunities: Research Projects - Thematic Grants