Proton-unbound states in AI 24 relevant for the mg 23 (p,γ) reaction in novae

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Date

2024

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Journal ISSN

Volume Title

Publisher

American Physical Society

Abstract

Background: The nucleosynthesis of several proton-rich nuclei is determined by radiative proton-capture reactions on unstable nuclei in nova explosions. One such reaction is 23Mg(p, γ ) 24Al, which links the NeNa and MgAl cycles in oxygen-neon novae. Purpose: The purpose of our study is to extract 23Mg(p, γ ) resonance strengths from proton-unbound states in 24Al, produced via the 24Mg(3 He,t) reaction. Methods: A beam of 3 He2+ ions at 50.7 MeV is used to produce the states of interest in 24Al. Proton-triton angular correlations are measured with a K = 600 QDD magnetic spectrometer and a silicon detector array, located at iThemba LABS, South Africa. Results: We measure the excitation energies of the four lowest proton-unbound states in 24Al and place lower limits on p/ values for these four states. Together with shell-model calculations of partial γ widths, the experimental data are also used to determine resonance strengths for the four lowest 23Mg(p, γ ) 24Al resonances. Conclusions: The energy of the dominant first 23Mg(p, γ ) resonance is determined to be Er = 478 ± 4 keV, with a resonance strength of ωγ = 19 ± 9 meV.

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Keywords

Proton emission, Charge-exchange reactions, Nuclear reaction rates, Resonance reactions, Research Areas Charge-exchange reactionsNuclear astrophysicsNuclear reaction ratesNucleosynthesis in explosive environments

Citation

Vyfers, E.C., Pesudo, V., Triambak, S., Adsley, P., Brown, B.A., Jivan, H., Kamil, M., Marin-Lambarri, D.J., Neveling, R., Ondze, J.C. and Papka, P., 2023. Study of proton-unbound states in $^{24}{\rm Al} $ relevant for the $^{23}{\rm Mg}(p,\gamma) $ reaction in novae. arXiv preprint arXiv:2311.15935.