Speaker
Description
Displaced events at colliders are a promising way, and in a large region of the
parameter space the only way, to test feebly interacting particles, for instance produced through freeze-in. However, if one assumes freeze-in production happens in the standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.
