Quarks and gluons are fundamental particles that are part of the Standard Model of particle physics. They are elementary particles, which means they are not composed of smaller particles.
Quarks: Quarks are the building blocks of matter and are considered fundamental particles. They are point-like particles with fractional electric charges. There are six known types or flavors of quarks: up (u), down (d), charm (c), strange (s), top (t), and bottom (b). Quarks have a property known as color charge, which comes in three types: red, green, and blue. Quarks can combine to form composite particles called hadrons, such as protons and neutrons.
Gluons: Gluons are particles that mediate the strong nuclear force, which is responsible for holding quarks together within hadrons. Gluons themselves carry the color charge and interact with quarks via the strong force. Unlike other fundamental forces, the strong force becomes stronger as the distance between quarks increases, a phenomenon known as confinement. Gluons are massless particles and are responsible for transmitting the strong force between quarks, binding them together within particles like protons and neutrons.
Quarks and gluons are subject to the strong nuclear force, electromagnetism, and the weak nuclear force. However, at everyday energy scales and in ordinary matter, the strong force dominates within the atomic nucleus, while electromagnetism governs interactions between charged particles. The weak force primarily appears in processes such as radioactive decays.