Antideuterons as a signature of supersymmetric dark matter

Abstract

Once the energy spectrum of the secondary component is well understood, measurements of the antiproton cosmic-ray flux at Earth will be a powerful way to indirectly probe for the existence of supersymmetric relics in the galactic halo. Unfortunately, it is still spoiled by considerable theoretical uncertainties. As shown in this work, searches for low-energy antideuterons appear in the meantime as a plausible alternative, worth being explored. Above a few $\mathrm{GeV}/n,$ a dozen spallation antideuterons should be collected by the future Alpha Magnetic Spectrometer experiment on board International Space Station Alpha. For energies less than $\ensuremath{\sim}3\mathrm{GeV}/n,$ the $\overline{D}$ spallation component becomes negligible and may be supplanted by a potential supersymmetric signal. If a few low-energy antideuterons are discovered, this should be seriously taken as a clue for the existence of massive neutralinos in the Milky Way.