Omega Baryon

Omega Baryon

The Omega baryons are a family of subatomic hadron particles which have the symbols Ω and have a +2, +1 or −1 elementary charge or are neutral. They are baryons containing no up or down quarks. Omega baryons containing top quarks are not expected to be observed as the Standard Model predicts the mean lifetime of top quarks to be roughly 5×10−25 s. This is about 20 times shorter than the timescale for strong interactions, and therefore it does not form hadrons.

The first Omega baryon discovered was the Ω−, made of three strange quarks, in 1964. The discovery was a great triumph in the study of quark processes, since it was found only after its existence, mass, and decay products had been predicted by American physicist Murray Gell-Mann in 1962 and independently by Yuval Ne'eman. Besides the Ω−, a charmed Omega particle (Ω0
c) was discovered, in which a strange quark is replaced by a charm quark. The Ω− decays only via the weak interaction and has therefore a relatively long lifetime. Spin (J) and parity (P) values for unobserved baryons are predicted by the quark model.

Since Omega baryons do not have any up or down quarks, they all have isospin 0.