Hadrons
Prof Dr. Marc WagnerGoethe-UniversitätInstitut für Theoretische PhysikMax-von-Laue-Str. 160438 Frankfurt
Partly it is not possible to calculate the full theory. This is where the lattice gauge theory comes into play.
Usually hadrons consist of 3 quarks or a quark-antiquark pair. But theoretically also states with four quarks are conceivable.