Production of antimatter nuclei in Galactic Cosmic rays.

Abstract

Antimatter nuclei in cosmic rays (CRs) are a promising tool for the indirect detection of darkmatter annihilation signatures. However, the search of new-physics signals in CRs relies on our knowledge of the astrophysical antimatter background which, in turns, depends critically on the several fragmentation cross-sections that regulate production and destruction of antiparticles in the interstellar medium. In this work, we have re-evaluated the astrophysical background of CR antiproton, antineutron, and antihelium nuclei in Galactic CRs using improved calculations. The production cross-sections of individual antinucleons are constrained using updated calculations that make use of recent accelerator data. The production of antideuteron and antihelium nuclei is calculated using an improved model of nuclear coalescence that accounts for the asymmetry in antineutron and antiproton production. We discuss the cross-section induced uncertainties and show that they are dominating in comparison with other uncertainties of astrophysical origin.

Antistars as possible sources of antihelium cosmic rays

“…There are models for the high-energy antihelium nuclei production in the inelastic CR collisions and due to dark matter (DM) annihilations (see e.g. [38][39][40][41][42][43] and references therein). Recently, the authors of [44] presented semi-analytical estimates of the antihelium-3 and antihelium-4 flux expected from the primary CR interactions with the interstellar medium.…”