Long-lived particles within the dark sector: promising signatures for dark matter searches at LHC

Many particle physics models for dark matter (DM) predict signatures at collider in the form of monojet. However, if the dark sector also contains long-lived particles (LLPs), less usual signatures can arise. In this talk I will discuss this possibility by considering two different models: the "pseudo-Dirac model", which predicts displaced vertices, and the "chromo-electric dipole model", which is characterized by composite states referred to as R-hadrons, by analogy to what happens in supersymmetry. In both cases, these unusual signatures can be complementary, or even competitive, with standard searches.