WIMPs

WIMPs, or weakly interacting massive particles, are hypothetical particles that interact with ordinary matter primarily through the weak nuclear force and gravity. They are a leading candidate for cold dark matter, potentially making up a substantial portion of the universe’s nonluminous matter. WIMPs are expected to have masses ranging from a few GeV to several TeV.

In the early universe, WIMPs would have been in thermal equilibrium with standard model particles. As the cosmos expanded and cooled, their annihilation rate fell below the expansion rate, leaving a relic population. This thermal WIMP scenario, often called the WIMP miracle, predicts a relic density close to the observed dark matter density if the interaction cross-section is at roughly the weak scale.

Typical WIMP properties include stability on cosmological timescales, electrical neutrality, and non-relativistic velocities today. The exact mass and couplings depend on the underlying theory. Well-known theoretical realizations include the neutralino in supersymmetry and various other beyond-Standard Model candidates.

Detection strategies target different aspects of WIMPs. Direct detection searches for nuclear recoils produced by WIMP scattering in underground detectors. Indirect detection looks for annihilation or decay products, such as gamma rays or neutrinos, from regions with high dark matter density. Collider experiments seek signs of WIMPs produced in high-energy collisions, inferred from missing transverse energy. Ongoing experiments such as large direct-detection experiments constrain parameter space, while collider and indirect searches complement these efforts.

As of now, no conclusive WIMP detection has been reported. Experiments have pushed many regions of parameter space into tighter constraints, but the WIMP hypothesis remains a central and well-motivated framework in the search for dark matter.