Displaced new physics at colliders and the pre-BBN universe

---

Resumo

Displaced events at colliders are a promising way, and in a large region of the parameter space the only way, to test dark matter produced via freeze-in. However, typical decay lengths as obtained from relic density calculations are way too large to observe anything in our detectors. In this talk, I will show how motivated modification of the cosmological history naturally lead to displaced events. Then I will discuss two classes of microscopic theories: a motivated top-down scenario with SUSY and PQ symmetry; a bottom-up classification of all possible interactions. Intriguingly, the observation of a displaced event at collider could reveal something about the thermal history of our universe.