The Bad Astronomer writes "Scientists at CERN announced today the discovery of a new fundamental subatomic particle that is almost certainly the Higgs boson — a particle that is crucial in giving other particles mass.
The new particle has a mass of about 125 — 126 GeV (roughly 125 times the mass of a proton) which is just what the Higgs mass is predicted to be by the Standard Model of particle physics. A signal was seen in preliminary results from 2011, but observations since then have raised the confidence level hugely: the strength of the signal indicates it is real to the 5 sigma level — that is, with 99.9999% confidence. In physics, that qualifies as a "discovery". This is a monumental step in particle physics, and toward our understanding of one of the most fundamental and mysterious properties of matter in the Universe: mass."