On November 19, scientists announced that, using data collected in 2012, they’d observed two new varieties of a class of tiny subatomic particles called baryons. You’ve probably already heard of two other types of baryons: protons and neutrons.
The thing that unites protons, neutrons, and the two new baryons is that they’re all made out of three even-smaller particles called quarks — one of the fundamental building blocks of all matter.
Quarks themselves come in six “flavors” (called up, down, strange, charm, bottom, and top). A proton is built from two up quarks and one down quark, while the new baryons are both made from one down quark, one bottom quark, and one strange quark.