What's the role of gluons?

One of the four fundamental forces of nature, the strong nuclear force is what holds the nucleus of an atom together. It is the force that binds protons and neutrons, the nucleus' constituents, in an atom. This force is incredibly powerful, yet it operates over a very short range, usually no more than a few femtometers (1 femtometer = 10^-15 meters).

Despite its short range, the strong nuclear force is the strongest of all four fundamental interactions, significantly stronger than electromagnetism, the weak nuclear force, and gravity. In fact, if it weren’t for the strong force, atomic nuclei couldn't withstand the electrostatic repulsion between positively charged protons - they would simply fly apart. The stability and abundance of matter in the universe, therefore, owe a lot to the workings of this force.

Gauge bosons are the carrier particles of the fundamental forces of physics. They're essentially the 'messengers' that mediate the interactions between particles. The four types of gauge bosons correspond to the four forces: gravitons for gravity (though not yet observed), photons for electromagnetism, W and Z bosons for the weak force, and gluons for the strong force.

Gluons, as gauge bosons, are unique because they carry the 'color charge' associated with the strong force and, unlike other forces, they can interact with themselves. This self-interaction leads to the property of confinement which means quarks are always found in groups, never alone. This quirk of gluons makes the strong force quite different from, say, electromagnetism, which is mediated by photons that do not carry electric charge and hence do not interact with each other.

Quarks are fundamental particles that make up protons and neutrons. They come in six 'flavors': up, down, charm, strange, top, and bottom. Quarks also carry a property known as 'color charge', which is, despite its name, not related to visual color but is an essential concept in understanding the strong force at the quantum level.

Quarks are never found in isolation due to confinement and it is gluons that are the mediators of the strong interaction which binds quarks together. The interaction between quarks is governed by Quantum Chromodynamics (QCD), the theory that describes the strong force. Under this theory, gluons can exchange color charge between quarks, leading to a continuous interaction that keeps quarks confined within larger particles like protons and neutrons.