Muon

A muon is a short-lived subatomic particle classified as a lepton. Muons have similar properties to an electron, however they are some 200 times heavier. Like electrons, they have antimatter counterparts as well. A build-up of muons in the dilithium chamber of starship's warp core will cause a warp core breach.

If a muon feedback beam is initiated while a full intensity power transfer is being conducted, a buildup of muons will develop in the warp core. If that ship was to then go to warp speed, the warp engines would explode. It would require a level 3 diagnostic of the dilithium chamber to detect the muon particle buildup. (TNG: "The Next Phase")

In 2370, Julian Bashir used muons to destroy the nanobiogenic harvester devices used by the T'Lani and the Kellerun during the war between their species. (DS9: "Armageddon Game")