From decades of discoveries made at particle colliders, we know that protons are composed of quarks bound together by gluons. We also know that there are six kinds of quarks, each one with its associated antiparticle. But are quarks fundamental? ATLAS searched for signs that quarks may have substructure in its most recent data, collected from the LHC’s proton-proton collisions in 2012.

The Large Hadron Collider commands many superlatives. One of the most useful of these is that the LHC is our planet's most powerful human-built microscope. The higher the collision energy, the tinier the distances you can study.

The ATLAS collaboration has announced the discovery of the χ_b(3P), which is a bound state of a bottom quark and bottom antiquark (bbar).