directdetection

Direct detection refers to experimental efforts to observe interactions between dark matter particles and ordinary matter by measuring the energy deposited when a dark matter particle collides with a detector material. It is one of three broad approaches to finding dark matter, alongside indirect detection of dark matter annihilation or decay products and collider production experiments.

Most experiments search for Weakly Interacting Massive Particles (WIMPs), though other candidates are considered. In the standard halo model, dark matter particles may scatter elastically off nuclei (nuclear recoils) or electrons (electronic recoils) in a detector, depositing keV-scale energies. Interaction rates are tiny, so experiments use large target masses, long exposure, and underground sites to reduce backgrounds.

Detector technologies include dual-phase liquid noble gas time projection chambers (for example, liquid xenon or argon) that measure scintillation and ionization signals to separate nuclear from electronic recoils, cryogenic crystal detectors (germanium, silicon) operating as bolometers, and other approaches such as bubble chambers and scintillators.

Backgrounds arise from natural radioactivity, cosmic rays, and solar neutrinos. Analyses use shielding, radiopure materials, veto systems, and discrimination techniques, reporting limits on the WIMP-nucleon cross section as a function of WIMP mass.

Current status: no confirmed detections have been reported. Experiments have set leading limits and continue toward larger-scale detectors and broader dark matter models, including light dark matter and axion-like particles. Direct detection remains a central element of the global search for dark matter.