Having accounted for essentially all of the known matter in our universe, one would expect that we have come to a head in terms of discovering the fundamental forces that govern the physical world. However, anomalies become obvious when we attempt to account for some phenomena in our universe. When predicting the speed of the expansion of the universe, scientists found that the galaxy was expanding at a far faster rate than they expected it to. With our current understanding, there must be some unknown type of energy, which physicists call dark energy. Another example of something we cannot explain is that stars and planets seem to move at a faster speed than predicted. What this means is that there are some substance in addition to what they orbit that we cannot see. Physicists refer to this as dark matter. Professor Wagoner said, “It’s like being in a room, all the lights are off, and you hear the door shut. You know there is something out there making the door shut, but you don’t know what it is. That’s dark matter and dark energy.”
Inexplicably tied with the search for this elusive fifth force, another mystery that Professor Wagoner’s research tries to help explain is the question of antimatter. You may already be familiar with the concept of antimatter if you have read Dan Brown’s Angels and Demons. Essentially, the fundamental particles all have an ‘anti’ equivalent. Anti-electrons are positive, have the same mass as our electron, and are known as positrons. Similarly, there are anti-neutrons and anti-protons. Normal matter and antimatter are observed in equal parts when particles collide at high speeds, but the universe is dominated by normal matter. “There is no physical reason we know of that explains why there is lot more normal matter than antimatter”, said Professor Wagoner. The explanation that Professor Wagoner and his lab are hypothesizing is revolutionary: a new particle called the “Axion”.
So how does this magical particle resolve those two puzzles? Physicists hypothesized a modification of the mathematical equation of the strong force with the addition of an extra term-“A”. What this essentially means is that this hypothetical particle “Axion” is mediating an additional type of force between matters. Because this force is very small, it has eluded our observations so far.
To prove the existence of Axion by experiments, Professor Wagoner and his lab created a situation where one can verify the effect of the Axion. In his experiment, two objects are put very close to each other. One of them is suspended on a very fine string, and the other object is moved to different orientations. The first object is measured to see if it moves according to the existing fundamental forces of physics. If any force is observed in addition to the four types of force we know of, then the existence of the Axion is supported.
According to Professor Wagoner, the search for the Axion is a cumulative effort. The hypothesis was first brought up in 1977 and the physical evidence for the Axion has been researched extensively since then. If the Axion is to be found, it will dramatically change the way we understand the world.