CERN's Large Hadron Collider has discovered a new class of particle

Better title: "CERN's Large Hadron Collider has discovered two pentaquark particles".

From the research paper:

> The significance of each of these resonances is more than 9 standard deviations.

9 sigmas is a lot, I guess they waited because pentaquarks are a polemic topic. Usually the discussion is about if it's really a pentaquark particle with 5 quarks, or it's only a baryon with 3 quarks traveling along with a meson with 2 quarks.