quasi-stable elementary particle

quasi-stable elementary particle

[¦kwä·zē ′stā·bəl ′el·ə‚men·trē ′pärd·ə·kəl]
(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.