Toward a new indirect approach for nuclear astrophysics. A case study

M. La Cognata, G. Kiss, O. Trippella, C. Spitaleri, A. M. Mukhamedzhanov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Fusion reactions play a key role in astrophysics, as they are responsible of energy production and nucleosynthesis. The characteristic temperatures range from 109 K in hot explosive scenarios to 106-107 K in quiescent burning in low-mass stars. Therefore, the relevant cross sections have to be known at energies smaller than ∼ 1 MeV. However, the Coulomb barrier and the electron screening effect make it very difficult to provide accurate cross sections. The presence of sub threshold resonances might radically alter the expected trend of the extrapolated cross section, leading to systematic errors. The 13C(α,n)16O reaction is an example of reactions characterized by strong sub threshold resonances. 13C(α,n)16O is the neutron source of the main component of the s-process, responsible of the production of most nuclei in the mass range 90 <A <204. It is active inside the helium-burning shell in AGB stars, at temperatures ∼ 108 K, corresponding to an energy interval of 140-230 keV. Though it plays a crucial role, no direct measurements exist inside the 140-230 keV range. Extrapolations through the R-matrix and indirect techniques such as the ANC yield inconsistent results. The discrepancy amounts to a factor of 3 or more. Therefore, we have applied the THM to the 13C(α,n)16O reaction. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM, allowing to attain an unprecedented accuracy in the 13C(α,n)16O study.This innovative approach, merging together two well establish indirect techniques, can find application in the study of a number of resonance reactions at deep sub Coulomb and even negative energies, where direct measurements are impossible.

Original languageEnglish
Title of host publicationProceedings of Science
PublisherProceedings of Science (PoS)
Volume07-11-July-2015
Publication statusPublished - 2014
Event13th Nuclei in the Cosmos, NIC 2014 - Debrecen, Hungary
Duration: Jul 7 2014Jul 11 2014

Other

Other13th Nuclei in the Cosmos, NIC 2014
CountryHungary
CityDebrecen
Period7/7/147/11/14

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ASJC Scopus subject areas

  • General

Cite this

La Cognata, M., Kiss, G., Trippella, O., Spitaleri, C., & Mukhamedzhanov, A. M. (2014). Toward a new indirect approach for nuclear astrophysics. A case study. In Proceedings of Science (Vol. 07-11-July-2015). [043] Proceedings of Science (PoS).