Conceptual computer illustration of a pentaquark. A pentaquark is subatomic particle consisting of four quarks and one antiquark bound together. Strong evidence for the pentaquark came from experiments at the Jefferson Lab in Newport News, Virginia during 2003. Data from CERN in 2015 provided conclusive evidence for a new state of matter. The discovery tells us something about the strong nuclear force and the way the smallest constituents of matter behave. The strong force is responsible for binding quarks together inside hadrons such as protons, neutrons and now, it seems, pentaquarks. It also binds protons and neutrons together inside atomic nuclei, and it does this despite the fact that protons have an enormous mutual repulsion due to their electric charges