24 hours ago3 min read

Have you heard about gluons?

Hola! I'm Alexa Guido, a young and curious woman passionate about science. Join me on an exciting journey to explore the wonders of the universe through the lens of physics.

Have you ever stopped to think about how particles stick together? It might sound a bit odd, but some incredibly powerful forces actually glue together our universe! While we don’t notice it in our day-to-day lives, there’s a fundamental force that binds quarks[1] together, acting like cosmic glue to form protons and neutrons.

Gluons are the little mediators particles of the Strong force, one of the four fundamental forces in nature. These massless particles are responsible for maintaining quarks together with one another. Gluons as force-carrying particles are massless, have a quantum spin of 1 and have no electric charge. Gluons are like the ultimate best friends, working tirelessly to maintain the integrity of atomic nuclei!

Now, this strong nuclear force is much stronger than the three other fundamental forces: gravity, electromagnetism, and the weak nuclear force. Gluons manage to hold all the matter in the universe together with a force so strong that separating quarks and gluons is extremely difficult; they are bound inside hybrid particles.

The only way we have achieved to separate these particles is by creating a special state of matter known as quark-gluon plasma. In this extreme environment, the density and temperature are so high that protons and neutrons “melt” revealing the fundamental building blocks of atomic nuclei!

Surprisingly, this soup of quarks and gluons permeated the entire universe until a few fractions of a second after the Big Bang, then the universe cooled down enough for quarks and gluons to freeze into protons and neutrons, resulting in the universe we see today.

So how do quarks and gluons interact? They’re like an adorable couple that shares everything! They stabilize each other, exchanging energy and information through the emission and absorption of gluons, just as electrically charged particles interact through the emission and absorption of photons, however, the nucleic family is here.

The theory behind this interaction is called quantum chromodynamics (QCD). The exchanges of quarks are described in terms of eight types of massless gluons, which, like the photon, all carry one unit of spin. Like quarks, the gluons carry a “strong charge” known as color, interacting between themselves through the strong force.

This color flickers randomly, continuously, and rapidly between red, green, and blue. There’s no point in assigning it a definite color, but we know that gluons have colors! - as in the image- In fact, gluons are not neutral under the strong nuclear force: they carry a color and an anti-color, resulting in different combinations that create those eight types of gluons.

This colorfulness of the gluon field has a significant impact on the quarks. Just by interacting with the gluon field around it, a red quark can turn green, or blue, over and over and over again at an extremely high rate.

Meanwhile, to make things worse, hadrons, the particles in which quarks, anti-quarks, and gluons are found in nature, never have a color at all; they are always in a neutral mood under the strong nuclear force because the “colors” of all the particles inside cancel, causing objects with color can never be isolated to be studied in detail.

Gluons do so much for us! This dynamic duo of quarks and gluons keeps our universe functioning seamlessly while cracking the brain of physics trying to understand their behavior. However, quantum chromodynamics is notoriously difficult to solve, but no fear! It can be simulated on supercomputers built and maintained at DOE facilities, the leaders since 1960!