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Direct measurement of the Li7(p,α)He4 reaction at astrophysical energies using the ELISSA array

H. Pai1,*, G. L. Guardo2, Sk M. Ali3, I. Kuncser1,4, A. Lupoae1,5, T. Petruse1, C. Matei1, Y. Xu1, S. Aogaki1 et al.

D. L. Balabanski1, S. R. Ban1,4, M. Brezeanu1, A. Cassisa6, M. La Cognata2, A. Cvetinović7, A. Dhal1, P. Figuera2, A. Kuşoğlu1,8, L. Lamia2,9,10, D. Lattuada2,11, V. Lelasseux1, Ó. E. López-López12, C. A. Marin1, C. V. Nedelcu1,4, A. Pappalardo2, I. P. Parlea1, R. G. Pizzone2,13, G. M. Restifo2,11, R. Roy1,14, P.-A. Söderström1, S. Niculae1, N. T. Szegedi2, V. A. Toma1, A. Tumino2,11, G. Turturica1, T. Tozar1, and N. Vukman15,16,17

  • *Contact author: haridas.pai@eli-np.ro; hari.vecc@gmail.com
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Phys. Rev. C 113, 045804 – Published 9 April, 2026

DOI: https://doi.org/10.1103/hlq9-7fyd

Abstract

A direct measurement of the Li7(p,α)He4 reaction at astrophysical energies was performed at the Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH) using a scaled-down version of the ELISSA detector array and the 3 MV Tandem accelerator. This reaction plays a crucial role in both primordial and stellar nucleosynthesis. In Big-Bang Nucleosynthesis (BBN), it is directly linked to the long-standing “Cosmological Lithium Problem,” the discrepancy between observed and predicted primordial Li7 abundances. In stellar environments, it constitutes the final step in the hydrogen-to-helium burning chain. The experiment utilized a Li7 beam incident on a CH2 target at ten laboratory energies (Elab) corresponding to center-of-mass energies (Ec.m.) ranging from 59.5 to 990 keV. The astrophysical S factors were extracted using both the Distorted Wave Born Approximation (DWBA) and polynomial fitting techniques. Updated reaction rates were calculated from the present DWBA results, supplemented by existing experimental data. The impact of the theoretical DWBA calculation on the reaction rate is investigated.

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Phys. Rev. C 113, 045804– Published 9 April, 2026
  • Received 30 October 2025
  • Revised 17 February 2026
  • Accepted 26 February 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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