Hypothetical Particles

5 Hypothetical Particles, The Discoveries Of Which Will Change The Course Of Science.

The field of particle physics is having the time of its life. With the development of the Large Hadron Collider in the first decade of this century, this field has become a popular one. The story began when Dalton hypothesised that matter is made up of tiny atoms that cannot be divided further. Dalton was wrong. Since his hypothesis, scientists have not only studied what's inside an atom, but also studied what's the tiniest entity that makes up the Universe. Hundreds of subatomic particles have been discovered experimentally. Most of them were first predicted theoretically. Today, let us have a look at the 5 most important particles, still in the shape of equations, the discoveries of which will change the course of science.

1. Magnetic Monopole

Predicted By: Grand Unified Theory

What Is It?

The magnetic monopole is a hypothetical particle that exists as a single isolated magnet with only one pole (north or south). When you cut a magnet from the middle, you don't get an isolated north or south pole. You get two smaller magnets with their own pairs of north and south poles. Like an isolated electric charge, there is no isolated magnetic charge. 

Magnetic Monopole
The magnetic monopole is an isolated north or south pole.

What will it change?

The first thing that the discovery of magnetic monopoles will change is the century old set of four Maxwell's equations that won the battle against the Newton's laws of motion when it came to formulate special relativity. With the monopoles now in picture, Gauss's law of magnetism and the Faraday's law will change. The divergence of magnetic field will no longer be zero. The only asymmetric part of these equations is that there is no single point source of magnetic field like the electric field. So the discovery of monopoles will now bring an utmost symmetry in the Maxwell's equations. There are only 2 ways to detect the monopole: Invent a magnetic monopole or observe the ones already created in the universe, neither of which has been successful yet.

Also Read: Why Maxwell's equations are so important and what do they really mean?

2. Graviton

Predicted By: String Theory

What Is It?

There are four fundamental forces of nature, three of which have an associated particle that caries that particular force. The strong force is carried by gluons, the weak force by W and Z bosons and the electromagnetic force by photons. These particles are a part of the famous Standard Model of particle physics. However, there is no associated particle for the force of gravity. Many quantum gravity theories predict the existence of such a particle, named graviton, that will be the force carrier of gravitational force.

The Standard Model of particle physics has no place for gravitons in it. 

What Will It Change?

Discovery of gravitons will really change the course of physics. It will show that gravitational field, just like the electromagnetic field, is a quantum field. This won't mean that general relativity is wrong. Steven Weinberg showed this 50 years ago. Also, the existence of gravitons will give the Standard Model of particle physics its first real blow. The theory has a wonderful past filled with successful predictions, the major one being that of Higgs Boson that was discovered earlier in the decade. With gravitons in picture, the theory will have to be extended to include them. However, the experimental confirmation of gravitons is quite difficult and impossible with modern day technology.

Also Read: What is String Theory?

3. Axion

Predicted By: Peccei-Quinn Theory

What Is It?

Axion is a hypothetical particle that is a possible candidate of the cold dark matter. It was postulated by the Peccei–Quinn theory in 1977 to resolve the strong CP problem in quantum chromodynamics (QCD).

Dark matter
Axions are one of the possible candidates of cold dark matter.

What Will It Change?

If Axions exist and have low mass, they can be further considered as the possible candidates of cold dark matter. The four Maxwell's equations will change too. There will be a fifth equation by the name axion law which is nothing but the famous Klein Gordon equation of quantum mechanics with an additional term in it. Because of their properties, axions would interact only minimally with ordinary matter. Axions would also change to and from photons in magnetic fields.

4. Inflaton

Predicted By: Alan Guth 

What Is It?

When the universe was 10-36 seconds old, it started expanding exponentially, at a rate greater than the speed of light (this doesn't violate relativity though). This continued for a small time and the event is known as the comic inflation. After the inflation, the universe expanded from the size of an atom to something that could be held in a hand. This idea is proposed by an eminent cosmologist, Alan Guth, who associates a hypothetical particle (inflaton) to the scalar field that caused this expansion (inflationary field) . So the inflaton is the quantum excitation of this scalar inflationary field.

The Big Bang model of cosmology will get a boost with the discovery of inflaton. 

What Will It Change?

The discovery of inflaton will confirm the inflation model given by Alan Guth. This is turn will be one of the strongest evidence in the favour of the Big Bang Theory along with the existence of the cosmic microwave background radiation. 

5. Tachyon 

Predicted By: Bosonic String Theory

What Is It?

A tachyon is a hypothetical particle that travels faster than light. Such a particle will have an imaginary mass according to the current laws of physics. Tachyons are also hypothesised particles present in the interior of a black hole.

Illustration of tachyons
The tachyon travels faster than light and experiences a space like universe according to special relativity.

What Will It Change?

The discovery of tachyons will give a mighty blow to the special theory of relativity according to which nothing can travel faster than light. It will also force us to develop a new theory, an extension of special relativity to incorporate these new particles. Also, the concept of imaginary mass will demand a physical explanation. Since the tachyons would travel faster than light, they could be used to build a tachyonic antitelephone and send signals faster than light, which (according to special relativity) would lead to violations of causality. In short, their discovery will cause a havoc in the world of science and bring out new, refined and advance theories that will explain them.

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