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

Journal Article · Tue Mar 11 04:00:00 EDT 2025 · Physical Review. C

DOI:https://doi.org/10.1103/PhysRevC.111.034609· OSTI ID:3000413

Magro, P. L. D. ^[1]; Guimarães, V. ^[1]; Linares, R. ^[2]; Rangel, J. ^[3]; Zamora, J. C. ^[4]; Rogachev, G. V. ^[5]; Koshchiy, E. ^[5]; Bishop, J. ^[6]; Barbui, M. ^[5]; Parker, C. E. ^[5]; Roeder, B. ^[5]; Saastomoinen, A. ^[5]

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1. Universidade de São Paulo (Brazil)
2. Universidade Federal Fluminense, Rio de Janiero (Brazil)
3. Universidade do Estado do Rio de Janeiro (Brazil)
4. Michigan State University, East Lansing, MI (United States)
5. Texas A&M University, College Station, TX (United States)
6. Texas A&M University, College Station, TX (United States); University of Birmingham (United Kingdom)

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. In this work, we report experimental data for the elastic scattering of ¹²N on ¹⁹⁷Au target at 𝐸_lab = 70 MeV. The ¹²N is a proton-rich nucleus with proton separation energy 𝑆_𝑝 = 600 keV, which is higher than the ⁸B (𝑆_𝑝 = 137 keV) and almost the same as the ¹⁷F (𝑆_𝑝 = 601 keV). 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 𝜎_𝑅. We also performed continuum discretized coupled-channel calculations to compare with the experimental data. 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, 𝜎_𝑅 = 1269 ± 41 mb. The agreement between the CDCC calculation and the experimental elastic scattering data is limited and the breakdown does not exhaust the measured 𝜎_𝑅. The resulting reduced reaction cross section 𝜎_Red 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. Here, more research is required to estimate the contribution of core excitation.

• Research Organization: Texas A&M University, College Station, TX (United States)
• Sponsoring Organization: USDOE Office of Science (SC); CNPq
• Grant/Contract Number: FG02-93ER40773
• OSTI ID: 3000413
• Journal Information: Physical Review. C, Journal Name: Physical Review. C Journal Issue: 3 Vol. 111; ISSN 2469-9985; ISSN 2469-9993
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

Elastic scattering reactions
Low & intermediate energy heavy-ion reactions
Nuclear reactions
Optical
coupled-channel & distorted wave models