Direct constraints on diffusion models from cosmic-ray positron data: Excluding the Minimal model for dark matter searches

Understand

Galactic Cosmic-ray (CR) transport parameters are usually constrained by the boron-to-carbon ratio.

• This procedure is generically plagued with degeneracies between the diffusion coefficient and the vertical extent of the Galactic magnetic halo.
• The latter is of paramount importance for indirect dark matter (DM) searches, because it fixes the amount of DM annihilation or decay that contributes to the local antimatter CR flux.
• These degeneracies could be broken by using secondary radioactive species, but the current data still have large error bars, and this method is extremely sensitive to the very local interstellar medium (ISM) properties.