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Description
Weakly interacting and massive particles, dubbed WIMPs, have been suggested as plausible candidates to the astronomical dark matter (DM). Should these putative species exist, they would continuously annihilate or decay within the Milky Way halo and yield rare antimatter particles -- such as antiprotons or positrons.
The discovery, and recent confirmation by AMS, of a cosmic ray lepton anomaly has raised the tremendous hope that WIMPs were not just a fantasy. Alas, the dust has now settled down and we are still hunting for them. I will review the observations and explain why they point towards the presence of an additional component of primary positrons on top of the expected background. Interpreting that excess as a smoking gun evidence for WIMPs is very tempting. However, that possibility has by now faded away on the basis of arguments which I will discuss. The positron excess is probably related to conventional astrophysical processes. I will conclude my talk by reviewing two of them -- pulsars and spallations at the acceleration sites.
