Displaced Dark Matter at Colliders

Abstract

Models in which the dark matter is very weakly coupled to the observable sector may explain the observed dark matter density, either as a "superWIMP" or as "asymmetric dark matter." Both types of models predict displaced vertices at colliders, with a rich variety of possible phenomenology. We classify the cases in which the decays can naturally occur inside particle detectors at the LHC, with particular focus on the nontrivial scenarios where the decaying particle is invisible. Identification of the position and timing of these invisible displaced vertices significantly improves the prospects of reconstructing the new physics in models such as supersymmetry. In many cases, reconstruction of the visible products of the displaced decay can determine the dark matter mass, allowing the dark matter density to be predicted from collider data.