The term "hadron" is a new Greek word introduced by L. B. Okun in a plenary talk at the 1962 International Conference on High Energy Physics at CERN. He opened his talk with the definition of a new category term: …

According to the quark model, the properties of hadrons are primarily determined by their so-called valence quarks. For example, a proton is composed of two up quarks (each with electric charge ++2⁄3, for a total of +4⁄3 together) and one …

Baryons are hadrons containing an odd number of valence quarks (at least 3). Most well-known baryons such as the proton and neutron have three valence quarks, but pentaquarks with five quarks—three quarks of different colors, and also one extra qua…