Enhanced One-Loop Corrections to WIMP Annihilation and their Thermal Relic Density in the Coannihilation Region

Understand

We consider quantum corrections to co-annihilation processes of Weakly Interacting Massive Particles (WIMPs) due to the exchange of light bosons in the initial state ("Sommerfeld corrections").

• We work at one-loop level, i.e.
• we assume that these corrections can be treated perturbatively.
• Co-annihilation is important if there is at least one additional new particle with mass close to the lightest WIMP, which is a Dark Matter candidate.