Direct Detection \([T_{0}]\)

Once we understood how dark matter can be produced in the early universe, from the inflationary phase to the thermal one, passing through the reheating process, it is time to question the possibility to detect this dark component largely present in our galaxy. The most natural way to detect it is through direct interaction with a nucleus on earth. direct detection (DD) was first proposed by Goodman and Witten (Phys Rev D 31:3059, 1985). The idea was to study the scattering of dark matter particles from the galactic halo with targets on earth and extract information about their masses and couplings to the standard model. Because dark matter is weakly interacting with standard matter, such experiments require large detectors (from 10 kilos for the first version to several tons for the future projects) and deeply buried underneath the surface of the earth to avoid contamination from cosmic rays. This is similar to neutrino detection experiments in the principle, except that dark matter is supposed to be quite massive. While neutrino scatterings generate a Cherenkov shower, a WIMP bumps into a heavy nuclei and experimentalists try to measure the energy of recoil produced by the interaction.