Determining the ¹³C(α, n)¹⁶O absolute cross section through the concurrent application of ANC and THM and astrophysical consequences for the s-process in AGB-LMSs.

¹ Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia, Italy
² I.N.F.N., Section of Perugia, Via A. Pascoli, 06123 Perugia, Italy
³ I.N.F.N., Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania, Italy

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

Published online: 30 December 2017

Abstract

The ¹³C(α, n)¹⁶O reaction is considered to be the most important neutron source for the s-process main component in low-mass asymptotic giant branch stars. No direct experimental data exist at very low energies and measurements performed through direct techniques show inconsistent results, mostly in their absolute values. In this context, we reversed the usual normalization procedure combining two indirect approaches, the asymptotic normalization coefficient and the Trojan Horse Method, to unambiguously determine the absolute value of the ¹³C(α, n)¹⁶O astrophysical S(E)-factor in the most relevant energy-region for astrophysics. Adopting the new reaction rate for the n-source in the NEWTON s-process nucleosynthesis code, astrophysical calculations show only limited variations, less than 1%, for those nuclei whose production is considered to be totally due to slow neutron captures.