xi hyperon[′zī ′hī·pə‚rän]
Also known as xi particle.
Collective name for the xi-minus and xi-zero particles, which form an isotopic-spin multiplet of quasi-stable baryons, designated Ξ, having a hypercharge of -1, a total isotopic spin of ½, a spin of ½, positive parity, and an average mass of approximately 1318 megaelectronvolts. Also known as cascade hyperon; cascade particle.
A baryon belonging to any isotopic-spin multiplet having a hypercharge of -1 and a total isotopic spin of ½; designated by ΞJP (m), where m is the mass of the baryon in MeV, and J and P are its spin and parity (if known); the Ξ3/2+ (1530) is sometimes designated Ξ*.