β\beta--Radioactive Cosmic Rays in a diffusion model: test for a local bubble?

In the present paper, we extend the analysis of Maurin et al. (2001) and Donato et al. (2001) to the $\beta$-radioactive nuclei $^{10}$Be, $^{26}$Al and $^{36}$Cl. These species are be shown to be particularly sensitive to the properties of the local interstellar medium (LISM). As studies of the LISM suggest that we live in an underdense bubble of extent r_{hole} \sim 50 - 200 \unit{pc}, this local feature must be taken into account. We present a modified version of our diffusion model which describes the underdensity as a hole in the galactic disc. It is found that the presence of the bubble leads to a decrease in the radioactive fluxes which can be approximated by a simple factor $\exp(-r_{hole}/l_{rad})$ where $l_{rad}=\sqrt{K \gamma \tau_0}$ is the typical distance travelled by a radioactive nucleus before it decays. We find that each of the radioactive nuclei independently point towards a bubble radius \lesssim 100 \unit{pc}. If these nuclei are considered simultaneously, only models with a bubble radius r_{hole} \sim 60 - 100 \unit{pc} are marginally consistent with data. In particular, the standard case r_{hole}=0 \unit{pc} is disfavoured. Our main concern is about the consistency of the currently available data, especially $^{26}$Al/$^{27}$Al.Comment: 21 pages, 11 figures, Latex, macro aa.cls, to appear in A&

Kaluza-Klein Dark Matter and Galactic Antiprotons

Extra dimensions offer new ways to address long-standing problems in beyond the standard model particle physics. In some classes of extra-dimensional models, the lightest Kaluza-Klein particle is a viable dark matter candidate. In this work, we study indirect detection of Kaluza-Klein dark matter via its annihilation into antiprotons. We use a sophisticated galactic cosmic ray diffusion model whose parameters are fully constrained by an extensive set of experimental data. We discuss how fluxes of cosmic antiprotons can be used to exclude low Kaluza-Klein masses.Comment: 14 pages, 7 figures, 3 table

Galactic Cosmic Ray Nuclei as a Tool for Astroparticle Physics

Cosmic Ray nuclei in the energy range 100 MeV/nuc - 100 GeV/nuc provide crucial information about the physical properties of the Galaxy. They can also be used to answer questions related to astroparticle physics. This paper reviews the results obtained in this direction, with a strong bias towards the work done by the authors at {\sc lapth}, {\sc isn} and {\sc iap}. The propagation of these nuclei is studied quantitatively in the framework of a semi-analytical two-zone diffusion model taking into account the effect of galactic wind, diffuse reacceleration and energy losses. The parameters of this model are severely constrained by an analysis of the observed B/C ratio. These constraints are then used to study other species such as radioactive species and light antinuclei. Finally, we focus on the astroparticle subject and we study the flux of antiprotons and antideuterons that might be due to neutralino annihilations or primordial black hole evaporation. The question of the spatial origin of all these species is also addressed.Comment: 53 pages, review paper. to appear in Research Signposts, "Recent Research Developments in Astrophysics

Anti-Matter in Cosmic Rays : Backgrounds and Signals

Recent PAMELA and ATIC data seem to indicate an excess in positron cosmic rays above approximately 10 GeV which might be due to galactic Dark Matter particle annihilation. However the background of this signal suffers many uncertainties that make our task difficult in constraining Dark Matter or any other astrophysical explanation for these recent surprising data.Comment: Proceedings for XLIVemes rencontres de Moriond, Electroweak Interactions And Unified Theories sessio

Galactic diffusion and the antiprotron signal of supersymmetric dark matter

The leaky box model is now ruled out by measurements of a cosmic ray gradient throughout the galactic disk. It needs to be replaced by a more refined treatment which takes into account the diffusion of cosmic rays in the magnetic fields of the Galaxy. We have estimated the flux of antiprotons on the Earth in the framework of a two-zone diffusion model. Those species are created by the spallation reactions of high-energy nuclei with the interstellar gas. Another potential source of antiprotons is the annihilation of supersymmetric particles in the dark halo that surrounds our Galaxy. In this letter, we investigate both processes. Special emphasis is given to the antiproton signature of supersymmetric dark matter. The corresponding signal exceeds the conventional spallation flux below 300 MeV, a domain that will be thoroughly explored by the Antimatter Spectrometer experiment. The propagation of the antiprotons produced in the remote regions of the halo back to the Earth plays a crucial role. Depending on the energy, the leaky box estimates are wrong by a factor varying from 0.5 up to 3.Comment: 14 pages, LaTeX, 4 postscript figures appended as uuencoded g-zipped tar fil