Abstract: A leading dark matter candidate is a Weakly Interacting Massive Particle (WIMP). The observed
dark matter abundance can be naturally obtained through freezeout of the thermal annihilation
rate. The defining feature of a thermal WIMP is that its total annihilation cross section is specified
through the average reaction-rate factor, ~ 3 x 10^-26 cm^3/s. Searches for dark matter annihilation products have set strong limits in certain cases, requiring that the dark matter mass be greater than around 100 GeV if annihilation proceed solely to b quarks (Fermi), τ leptons (Fermi), or electrons (AMS). We construct the first limits on the total annihilation cross section, showing that allowed combinations of the annihilation-channel branching ratios considerably weaken these limits.
We will show that GeV-mass thermal WIMPs have not yet been adequately tested, and outline ways forward.