Propagation of secondary antiprotons and cosmic rays in the Galaxy

Abstract

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., B/C) produce too few antiprotons. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux AND B/C ratio to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh local "unprocessed" component at low energies perhaps associated with the Local Bubble, thus decreasing the measured secondary to primary nuclei ratio. The independent evidence for SN activity in the solar vicinity in the last few Myr supports this idea. The model reproduces antiprotons, B/C ratio, and elemental abundances up to Ni (Z<=28). Calculated isotopic distributions of Be and B are in perfect agreement with CR data. The abundances of three "radioactive clock" isotopes in CR, 10Be, 26Al, 36Cl, are all consistent and indicate a halo size z_h~4 kpc based on the most accurate data taken by the ACE spacecraft.

6 pages, 5 ps-figures, cospar.sty; Proc. of 34th COSPAR Scientific Assembly (Houston, 10-19 October 2002). Submitted to Advances in Space Research. More details can be found at http://www.gamma.mpe-garching.mpg.de/~aws/aws.html

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• Dark Matter Annihilation into Four-Body Final States and Implications for the AMS Antiproton Excess
• Propagation model for cosmic ray species in the Galaxy
• Modulation of cosmic ray anti-protons in the heliosphere: simulations for a solar cycle
• Transport of exotic anti-nuclei: I- Fast formulae for antiproton fluxes
• Transport of exotic anti-nuclei: II- Antiproton and Antideuteron astrophysical uncertainties