Determination of the nature of Dark Matter (DM) is one of the most fundamental problems of particle physics and cosmology. If DM is light enough and interacts with Standard Model particles directly or via some mediators with a strength beyond the gravitational one, it can be directly produced at the Large Hadron Collider or future particle accelerators. The typical signature from DM produced in particles collisions is missing transverse energy, MET, due to the fact that they escape undetected from the experimental apparatus. We present study of the complete set of dimension 5 and 6 effective operators with scalar, fermion and vector DM and explore possibility to distinguish these operators and characterise the spin of DM. We have found that, depending on the spin of the DM, the DM parts of the effective operators lead to a different energy dependence of the cross-sections and to different distributions of the invariant mass of the DM pair, and consequently to different MET distributions. We have found that at the LHC with high luminosity, certain classes of EFT operators can be distinguished from each other and, through this, it is possible to characterise the spin of DM in some cases. This study can be directly applied beyond the EFT paradigm, as we demonstrate for two cases -- Supersymmetry and inert two Higgs doublet model (i2HDM).
We find limits using LHC mono-jet data, spin independent and spin dependent direct searches, relic density and CMB, and show an important role of the interplay between high and low energy data in exploring DM and identification its nature.
We also highlight prospects of new signature from DM theories such as disappearing charge tracks which are characteristic for wide class of DM theories and demonstrate the LHC potential to explore them using examples with of i2HDM and Minimal Spin-one Isotriplet Dark Matter models.
We show that collider and non-collider DM searches have a unique power to probe the nature of Dark Matter using examples of several appealing DM theories.