quasi-stable elementary particle [¦kwä·zē `stā·bǝl `el·ǝ´men·trē `pärd·ǝ·kǝl] PARTICLE PHYSICS A term formerly (before the discovery of charmed particles) used for elementary particles that cannot decay into other particles through strong interactions and that have lifetimes longer than 10-20 second. Also known as semistable elementary particle. |