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Measurement of the F19(p,αγ)O16 astrophysical factor at threshold energies

X. D. Su1,2,3,4,5, A. Psaltis6, M. La Cognata7,*, L. Roberti7,8,9,10, A. A. Oliva7, N. Vukman11,12,13, G. G. Rapisarda14,7, M. Mazzocco4,5,†, G. L. Zhang3,‡ et al.

F. Andreis11,15, B. Becherini11,15, X. Z. Cai1,2, J. G. Chen1,2, S. Cherubini14,7, M. Costa7, G. D'Agata14,7, A. Di Pietro7, P. Figuera7, G. L. Guardo7, M. Gulino16,7, S. Hayakawa17,7, I. Indelicato14,7, M. La Commara18,19, L. Lamia14,20,7, D. Lattuada16,7, A. Nurmukhanbetova16,7, S. Palmerini11,15,8, R. G. Pizzone14,7, S. M. R. Puglia14,7, S. Romano14,20,7, M. L. Sergi14,7, R. Spartà16,7, C. Spitaleri14,7, A. Togni4,5, D. Torresi7, O. Trippella11,15, and A. Tumino16,7

  • *Contact author: lacognata@lns.infn.it
  • †Contact author: marco.mazzocco@pd.infn.it
  • ‡Contact author: zgl@buaa.edu.cn
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Phys. Rev. C 114, 045809 – Published 19 October, 2026

DOI: https://doi.org/10.1103/bnc6-z6hj

Abstract

Proton-induced reactions on F19 can lead to different branches of the CNO cycles, possibly resulting in the synthesis of heavier nuclei. For instance, CNO breakout is considered to be a viable path to the production of calcium in the most metal-poor stars. Present-day observational studies indicate that F19 is mostly produced in the asymptotic giant branch phase of low- and intermediate-mass stars, and its synthesis and surface abundance are strictly intertwined with the production of heavy elements through slow neutron captures (s-process). Therefore, F19 can act as a probe of nucleosynthesis scenarios and stars inner structure. In recent years, new experimental data on F19 destruction reactions have been published, highlighting the occurrence of several resonances at astrophysical energies close to the proton threshold. While direct measurements relied on extrapolation from higher energies, indirect measurements made it possible to cover the astrophysical energies. In this work we will focus on the threshold region, which has been studied by means of the Trojan Horse method (THM) in the framework of the modified R-matrix approach. Thanks to this novel measurement, we could derive the asymptotic normalization coefficient (ANC) of the −448 keV subthreshold resonance and the strength of the 11 keV one, which turned out to be significantly lower than previously extrapolated. To evaluate the astrophysical impact, we calculated the astrophysical reaction rates using a modern Monte Carlo approach, constraining them with the ANC and threshold resonance strengths measured via the THM.

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Phys. Rev. C 114, 045809– Published 19 October, 2026
  • Received 28 June 2026
  • Accepted 17 September 2026
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