Ω粒子，一类重子，其组成不包含上夸克与下夸克。第一种Ω于1964年发现，由3个奇夸克组成。

The Omega baryons are a family of subatomic hadron particles that are represented by the symbol Ω and are either neutral or have a +2, +1 or −1 elementary charge. They are baryons containing no up or down quarks. Omega baryons containing top quarks are not expected to be observed. This is because the Standard Model predicts the mean lifetime of top quarks to be roughly 6975500000000000000♠5×10 s, which is about a twentieth of the timescale for strong interactions, and therefore that they do not form hadrons.