Indirect study of 12C(α,γ)16O reaction

6th Nuclear Physics in Astrophysics

物理学;天文学

Hammache, F.^1 ; Oulebsir, N.^1,2 ; Roussel, P.^1 ; Pellegriti, M.G.^1,6 ; Audouin, L.^1 ; Beaumel, D.^1 ; Bouda, A.^2 ; Descouvemont, P.^3 ; Fortier, S.^1 ; Gaudefroy, L.^4,7 ; Kiener, J.^5 ; Lefebvre-Schuhl, A.^5 ; Tatischeff, V.^5

Institut de Physique Nucléaire d'Orsay, UMR8608, IN2P3-CNRS, Université Paris Sud 11, Orsay

91406, France^1

Université Abderrahmane Mira, Bjaa

06000, Algeria^2

Physique Théorique et Mathématique, ULB, CP229, Brussels

B-1050, Belgium^3

GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, Caen Cedex 5

F-14076, France^4

CSNSM, UMR 8609, CNRS/IN2P3, Université Paris Sud 11, Orsay

F-91405, France^5

Dipartimento di Fisica e Astronomia, Universitá di Catania, Laboratori Nazionali Del Sud, INFN, Catania, Italy^6

CEA, DAM, DIF, Arpajon

F-91297, France^7

关键词: Differential cross section;    Helium-burning;    Incident energy;    Normalization constants;    R-matrix calculation;    Radiative capture;    Spectroscopic factors;    Transfer reaction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/665/1/012007/pdf
DOI  :  10.1088/1742-6596/665/1/012007

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

The radiative capture reaction12C(α,γ)16O plays an important role in helium burning in massive stars and their subsequent evolution [1]. However, despite various experimental studies, the cross section of this reaction at stellar energies remains highly uncertain. The extrapolation down to stellar energy (Ecm∼300 keV) of the measured cross sections at higher energies is made difficult by the overlap of various contributions of which some are badly known such as that of the 2+ (Ex=6.92 MeV) and 1-(Ex=7.12 MeV) sub-threshold states of16O. Hence, to further investigate the contribution of these two-subthreshold resonances to the12C(α,γ)16O cross section, a new determination of their a-reduced widths and so their a- spectroscopic-factors was performed using12C(7Li,t)16O transfer reaction measurements at two incident energies and a detailed DWBA analysis of the data [2]. The measured and calculated differential cross sections are presented as well as the obtained spectroscopic factors and the a- reduced widths as well as the assymptotic normalization constants (ANC) for the 2+ and 1-subthreshold states. Finally, the results obtained from the R-matrix calculations of the12C(α,γ)16O cross section using our obtained a-reduced widths for the two sub-threshold resonances are presented and discussed.