In particle physics, the baryon family refers to particles that are made up of three quarks. Quarks form a group of six particles that differ in their masses and charges. The two lightest quarks, the so-called "up" and "down" quarks, form the two atomic components, protons and neutrons. All baryons that are composed of the three lightest quarks ("up", "down" and "strange" quarks) are known. Only very few baryons with heavy quarks have been observed to date. They can only be generated artificially in particle accelerators as they are heavy and very unstable.