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Propagation des rayons cosmiques dans un modele de diffusion : une nouvelle estimation des parametres de diffusion et du flux d'antiprotons secondaires

Abstract : Dark matter is present at several scales of the universe (galaxies, cluster of galaxies, universe in the whole). This matter plays an important role in cosmology and can not be totally explained by conventional physics. From a particle physics point of view, there exists an extension of the standard model - supersymmetry - which predicts, under certain conditions, the existence of new stable and massive particles, the latter interacting weakly with ordinary matter. Apart from direct detection in accelerators, various indirect astrophysical signatures are possible.

This thesis focuses on one particular signature : the disintegration of these particles could yield antiprotons which should be measurable in cosmic rays. The present study evaluates the backgroung corresponding to this signal i.e. antiprotons produced in the interactions between these cosmic rays and interstellar matter. In particular uncertainties of this background being correlated to the uncertainties of the diffusion parameterm, a major part of this thesis is devoted to nuclei propagation.

The first third of the thesis introduces propagation of cosmic rays in our galaxy, emphasizing on the nuclear reactions responsible for the nuclei fragmentation. In the second third, different models are reviewed, and in particular links between the leaky box model and the diffusion model are recalled ; reacceleration and convection are also discussed. This leads to a qualitative discussion about information that one can infer from propagation of these nuclei. In the last third, we finally present detailed solutions of the bidimensionnal diffusion model, along with constraints obtained on the propagation parameters. The latter are applied to the antiprotons background signal, which concludes the work done in this thesis.

The propagation code for nuclei and antiprotons developped here has proven its ability in data analysis. It will probably be of interest for the analysis of the cosmic ray data which will be taken by the ams experiment on board the International Space Station in 2003.
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https://tel.archives-ouvertes.fr/tel-00008773
Contributor : David Maurin <>
Submitted on : Monday, March 14, 2005 - 3:54:26 PM
Last modification on : Tuesday, September 29, 2020 - 3:56:02 PM
Long-term archiving on: : Friday, April 2, 2010 - 9:44:39 PM

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  • HAL Id : tel-00008773, version 1

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David Maurin. Propagation des rayons cosmiques dans un modele de diffusion : une nouvelle estimation des parametres de diffusion et du flux d'antiprotons secondaires. Astrophysique [astro-ph]. Université de Savoie, 2001. Français. ⟨tel-00008773⟩

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