sigma particle Word Origin noun Physics.
- an unstable hyperon having positive, negative, or zero electric charge and strangeness −1. Symbol: Σ
Origin of sigma particle First recorded in 1960–65 Also called sigma baryon. sigma baryon in Science sigma baryon
- Any of three unstable subatomic particles in the baryon family, having a mass 2,328 to 2,343 times that of the electron and a positive, neutral, or negative electron charge. See Table at subatomic particle.