Determination of the .sup.3./sup.He(α, γ).sup.7./sup.Be and .sup.6./sup.Li(p, γ).sup.7./sup.Be astrophysical factors down to zero energy using the asymptotic normalization coefficients

0572943 - ÚJF 2024 RIV FR eng C - Konferenční příspěvek (zahraniční konf.)
La Cognata, M. - Kiss, G. G. - Yarmukhamedov, R. - Tursunmakhatov, K. I. - D'Agata, Giuseppe - Hons, Zdeněk - Mrázek, Jaromír … celkem 41 autorů
Determination of the ³He(α, γ)⁷Be and ⁶Li(p, γ)⁷Be astrophysical factors down to zero energy using the asymptotic normalization coefficients.
EPJ Web of Confereneces. Vol. 279. Les Ulis: edp sciences, 2023, č. článku 11001. ISSN 2100-014X.
[Conference on Nuclear Physics in Astrophysics /10./. Geneva (CH), 05.09.2022-09.09.2022]
Institucionální podpora: RVO:61389005
Klíčová slova: astrhopysical factors * nuclear reactions
Obor OECD: Astronomy (including astrophysics,space science)
https://doi.org/10.1051/epjconf/202327911001

The p - p-chain reaction He-3(alpha, gamma)Be-7 can sensitively influence the prediction of the Be-7 and B-8 neutrino fluxes. Despite its importance, the knowledge of its reaction cross section at energies of the core of the Sun (15 keV - 30 keV) is limited and the accuracy far from the desired similar to 3% level. In the present paper the indirect measurement of the external capture contribution using the asymptotic normalization coefficient (ANC) technique is reported. The angular distributions of deuterons emitted in the Li-6(He-3,d)Be-7 alpha-transfer reactions were measured and the ANCs extracted from the scaling of distorted-wave Born approximation (DWBA) and coupled-channel (CC) calculations. Then, the astrophysical S-factor for the He-3(alpha, gamma)Be-7 reaction was calculated assuming E1 direct capture and the zero energy value turned out to be 0.534 +/- 0.025 keVb. Both our experimental and theoretical approaches were benchmarked through the analysis of the Li-6(p,gamma)Be-7 astrophysical factor, with interesting astrophysical applications to the understanding of the primordial lithium problem. In particular, the present work disfavors the occurrence of a claimed 200 keV resonance in the astrophysical factor.
Trvalý link: https://hdl.handle.net/11104/0343470