The ancient Greeks were the first to assume the existence of the atoms, the smallest particles of the universe. But it didn’t end just there. Over a thousand of years later, the atom was discovered to even be made of protons, neutrons and electrons. And these three subatomic particles are even made of much tinier matter called quarks.
The deeper that we dig into the structure of the universe, the more questions emerge than are answered. Are space and time made of clusters of particles that seem get tinier and tinier that we can’t even see? The mysteries of these particles make them even more fascinating, and because of this, scientists (even up to this day) have assumed certain kinds of particles exist — called theoretical (or hypothetical) particles — but almost all of them haven’t been observed yet.
The Higgs boson is also known as the “God particle.” It derived its alias from The God Particle: If the Universe is the Answer, What is the Question? written by Leon Lederman. According to the author, the article has such an ominous moniker because it is quite paramount to the state of physics today, so critical to humankind’s understanding about the composition of matter, yet so evasive. So it implies that this particle “behaves” in a way, like God.
Theoretical physicist Peter Higgs was the first person to assume this particle existed and which was tentatively found on March 14, 2013. In layman’s terms, different subatomic particles are accountable for giving matter various properties. Mass is one of the most enigmatic yet important properties. Some particles like protons and neutrons have mass; the others (such as photons) do not. The “God particle” is presumed to be the particle that gives mass to other particles. And if that turned out to be real, it will certainly occupy vast gaps in the Standard Model, which explains the fundamental forces of nature, for the exception of gravity.
Why is this discovery so important? It has been seen as the “missing piece” in the Standard Model. Another, it has proven that the Higgs’ field does exist, without which the universe would have no matter as most of us know. Inspite of that, our quest for the knowledge pertaining to particle physics is not yet over. The “God particle” is far from perfect and only makes up less than 5% of our universe.
Another theoretical particle is the graviphoton which arises from the excitation of the gravitational field in a 5th dimension. It may possibly have the traits of a graviton (which will be defined later here), but it may also have the characteristics of a photon and make a “fifth force,” a term coined by physicists (presently there are four fundamental forces of nature — gravity, electromagnetism, strong force, and weak force).
The graviton “transmits” the gravitational force from its field, but like other theoretical particles, it has never been observed, whether directly or indirectly. It is usually presumed to be a fundamental particle which has zero charge and rest mass that is held to be the quantum of a gravitational field.
Preons are another hypothetical particle. They are believed to be so tiny that they reside within the elementary particles. Things are made of atoms, which in turn are made of particles, so hence the particles may be made of preons. Maybe every particle is made of two to three preons. Since fundamental particles were seen to deteriorate, then it is assumed that these fundamental particles are composed of real fundamental preons, which would simply undergo an exchange during decomposition, which leads to the particles’ change in their properties.
Although those who believe that preons exist are just a minority in the science territory, this did not prevent scientists from presenting preon models, leading more scientists to consider the possibility of the preons’ existence.
A sparticle (or a superpartner) is another hypothetical particle in the Supersymmetry Theory, which states that every particle in the universe has a duplicate particle. For instance, for every quark in the universe, there’s another quark which is perfectly symmetrical with it.
So if every particle has a twin particle (and there should be a lot of them), why are these particles not yet observable?
In particle physics, heavier particles deteriorate quicker than lighter ones, and if a particle becomes heavy enough, it decays immediately once it’s made. So presuming that a sparticle gets heavy, it would break down immediately. On the other hand, the sparticle’s superpartner (the observable particles) keeps on existing. This could also give an explanation of why there’s a lot of matter in our universe yet the dark matter comes in scarce numbers. It’s because the sparticles could be made of dark matter and live within a field which can’t be observed just yet.
Strangelets are composed of an entirely different form of matter called quark matter of strange matter, which is constructed in the core of vast neutron stars. The remains of the collapsed neutron stars have masses that range from four to eight times that of the Sun. The pressure and the temperature is quite high that it leads to protons and electrons in atomic nuclei fusing together, becoming neutrons. It results in what is called as “neutronium,” which is composed of vast numbers of neturons clustered together, becoming remarkably more dense than the usual matter.
Almost all particles look like tiny dots (or points) with 0 dimension. But in the string theory, the particles don’t look like dots or points at all, but strings, and also have one dimensional particle strands. This theory depicts how these stings proliferate by the help of space and how they connect with each other.
Tachyons are another theoretical particle whose movements are remarkably faster than the speed of light. However, most scientists still stick to Einstein’s theory of relativity which states that nothing can travel faster than the speed of light, thus they believe that tachyons never existed at all.
Most of us know that matter is composed of particles. So in the same manner, an anti-matter is made up of antiparticles which is another hypothetical particle. Antiparticles possess the same mass as particles do but antiparticles have an otherwise opposite charge (including electric charge) as well as an opposite spin. For instance, an electron’s antiparticle is the positively-charged neutron, which naturally occurs in particular types of radioactive (nuclear) decay. Antiparticles behave in the same way as particles, so basically every particle has its own anti-particle.
However, the problem is that since there’s a plethora of matter around, but antimatter really doesn’t exist anywhere (in the exception of the Large Hadron Collider, so antiparticles now do really exist and are no longer considered hypothetical).
In quantum physics, membranes or branes are hypothetical particles which have the capability to propagate through space. They generally establish the concept of a point particle to greater dimensions. For instance, a point particle has a brane of 0 dimension, while a string particle has a brane of 1 dimension.