Displaced Vertices from X-ray Lines

Understand

We present a simple model of weak-scale thermal dark matter that gives rise to X-ray lines.

• Dark matter consists of two nearly degenerate states near the weak scale, which are populated thermally in the early universe via co-annihilation with slightly heavier states that are charged under the Standard Model.
• The X-ray line arises from the decay of the heavier dark matter component into the lighter one via a radiative dipole transition, at a rate that is slow compared to the age of the universe.
• The model predicts observable signatures at the LHC in the form of exotic events with missing energy and displaced leptons and jets.