Indirect methods in nuclear astrophysics: Recent results from ANC and THM

Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, 95123 Catania, Italy

^* e-mail: lacognata@lns.infn.it

Published online: 7 June 2024

Abstract

Nuclear reactions within stars typically occur at energies significantly below 1 MeV. Consequently, the Coulomb barrier exponentially suppresses the cross section, reducing it to values as small as a few nanobarns for charged particles. This challenge in obtaining accurate input data for astrophysics has led to the introduction of indirect methods. Specifically, techniques such as ANC and THM have been employed to derive cross sections for reactions involving photons and charged particles in the exit channel, respectively, eliminating the need for extrapolation. The discussion delves into recent results from the application of these methods. For instance, the ⁶Li(³He,d)⁷Be measurement is utilized to deduce the ANC’s of the ³He+⁴He→ ⁷Be and p+⁶Li→ ⁷Be channels, along with their corresponding radiative-capture cross sections. Additionally, the THM measurement of the ²⁷Al(p, α)²⁴Mg cross section via the ²H(²⁷Al,α ²⁴Mg)n reaction is highlighted. In both cases, the cross section at astrophysical energies has been established with unprecedented accuracy.