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The variation of fundamental constants and the role of A=5 and A=8 nuclei on primordial nucleosynthesis
Coc A., Descouvemont P., Olive K., Uzan J.P., Vangioni E.
Physical Review D 86 (2012) 043529 - http://hal.in2p3.fr/in2p3-00727279
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique
The variation of fundamental constants and the role of A=5 and A=8 nuclei on primordial nucleosynthesis
A. Coc1, P. Descouvemont2, K. Olive, J. P. Uzan3, E. Vangioni3
1 :  CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
CNRS : UMR8609 – IN2P3 – Université Paris XI - Paris Sud
batiments 104 et 108 - 91405 Orsay Campus
2 :  ULB - Département d'Informatique [Bruxelles]
Université Libre de Bruxelles
Campus de la Plaine ULB CP212, boulevard du Triomphe, 1050 Bruxelles
3 :  IAP - Institut d'Astrophysique de Paris
CNRS : UMR7095 – INSU – Université Pierre et Marie Curie (UPMC) - Paris VI
98bis, bd Arago - 75014 Paris France
We investigate the effect of a variation of fundamental constants on primordial element production in big bang nucleosynthesis (BBN). We focus on the effect of a possible change in the nucleon-nucleon interaction on nuclear reaction rates involving the A=5 (Li-5 and He-5) and A=8 (Be-8) unstable nuclei and complement earlier work on its effect on the binding energy of deuterium. The reaction rates for He3(d,p)He4 and H3(d,n)He4 are dominated by the properties of broad analog resonances in He-5 and Li-5 compound nuclei respectively. While the triple alpha process is normally not effective in BBN, its rate is very sensitive to the position of the "Hoyle state" and could in principle be drastically affected if Be-8 were stable during BBN. The nuclear properties (resonance energies in He-5 and Li-5 nuclei, and the binding energies of Be-8 and D) are all computed in a consistent way using a microscopic cluster model. The n(p,gamma)d, He3(d,p)He4 and H3(d,n)He4 and triple-alpha reaction rates are subsequently calculated as a function of the nucleon-nucleon interaction that can be related to the fundamental constants. We found that the effect of the variation of constants on the He3(d,p)He4 and H3(d,n)He4 and triple-alpha reaction rates is not sufficient to induce a significant effect on BBN, even if Be-8 was stable. In particular, no significant production of carbon by the triple alpha reaction is found when compared to standard BBN. We also update our previous analysis on the effect of a variation of constants on the n(p,gamma)d reaction rate.

Articles dans des revues avec comité de lecture
Physical Review D (Phys. Rev. D)
Publisher American Physical Society
ISSN 1550-7998 (eISSN : 1550-2368)

PACS numbers: 98.80.Cq
14 pages, 12 figures
Astrophysics - Cosmology and Extragalactic Astrophysics – High Energy Physics - Phenomenology
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