WISP (particle physics)

In particle physics, the acronym WISP refers to a largely hypothetical weakly interacting sub-eV particle, or weakly interacting slender particle, or weakly interacting slim particle – low-mass particles which rarely interact with conventional particles.

The term is used to generally categorize a type of dark matter candidate, and is essentially synonymous with axion-like particle (ALP). WISPs are generally hypothetical particles.

WISPs are the low-mass counterpart of weakly interacting massive particles (WIMPs).