WIMP

WIMP stands for weakly interacting massive particle, a class of hypothetical particles proposed as constituents of dark matter. WIMPs are envisioned as having mass on the order of a few GeV to multi-TeV and interacting with ordinary matter predominantly through gravity and the weak nuclear force, making them difficult to detect directly.

The concept arose in the context of theories that extend the Standard Model, such as supersymmetry, extra dimensions, or technicolor. A common prototype is the neutralino, the lightest supersymmetric particle, which would be stable in many models due to a conserved parity. The term “WIMP miracle” refers to the observation that a particle with weak-scale interactions in thermal equilibrium in the early universe would naturally yield a relic abundance that matches the observed dark matter density.

Experimental searches for WIMPs fall into three broad categories. Direct detection aims to observe rare nuclear recoils from WIMP scattering in highly sensitive detectors, often using liquid xenon or other targets (examples include XENON1T, XENONnT, LUX-ZEPLIN, PandaX). Indirect detection searches for products of WIMP annihilation or decay, such as gamma rays, positrons, or neutrinos, using instruments like Fermi-LAT, AMS-02, and IceCube. Collider searches look for events with missing transverse energy that could indicate WIMP production, typically at the Large Hadron Collider. As of now, no unambiguous WIMP signal has been observed, and experiments have set increasingly stringent upper limits on interaction cross sections and annihilation rates.

The lack of detection has led to renewed exploration of broader parameter spaces and alternative dark matter candidates, while the WIMP paradigm remains a central focus of dark matter research. Future experiments with greater sensitivity aim to probe deeper into the viable WIMP parameter space.