Hadrons are a principal class of subatomic particles and had the most significant role in the building up of matter. They are composite particles made of quarks bound together by the strong force mediated through particles called gluons. Hadrons can be divided into two major classes: baryons and mesons.
Baryons
Baryons are hadrons containing three quarks. Most well-known are the baryons called the proton and neutron that comprise the nucleus of an atom. Protons are positively charged, neutrons have zero charge. It is through the interactions of baryons that atomic nuclei are stable.
Mesons
Mesons combine one quark with one antiquark. They are unstable and tend to break up into other types of particles relatively fast. However, they are of a very great importance as they are the carriers of the strong force between the baryons in the nucleus. Typical examples of mesons are pions and kaons.
Properties of Hadrons
Hadrons have many properties of importance in their study:
