The scientific explanation of what exactly is happening within a particle accelerator experiment is not that complicated. It relies on just a couple fundamental laws.

The basic principles of how particle accelerators teach scientists about the universe and its constituent particles are rather simple:

It begins with Einstein’s famous equation: E = mc².

This equation has proven useful to scientists in many different situations, but especially so in the area of particle physics. This powerful tool is called the principle of mass-energy equivalence, and simply states that mass and energy are the same thing, and can thus be turned into one another.

How does this apply to particle physics?

Smashing Particles Together

The basic idea of those who use particle accelerators is to discover new principles about the behavior of subatomic particles. In order to do that, they have to begin by understanding a few things.

As an example, what if an experimental physicist wanted to discover a new particle that a theoretical physicist had previously postulated. “It simply must exist,” says the theoretical physicist after slaving over the mathematics for weeks, “and if it does, it will have such and such mass and such and such charge, etc.”

Now, it is the experimentalist’s job to see if the theorist is right. Fortunately, he understands a few things about how particles are discovered.

He knows that if he is going to be able to “create” this new particle, he will need to begin with a certain amount of energy (which will correspond to the mass of the particle he is trying to create, a la Einstein’s equation).

He knows that in order to get that much mass, he will have to smash other, previously existing particles together at energies even greater than that (much “excess” energy is put into these collisions, as much energy is wasted in the process).

When Particles Collide

When particles are sped up in a particle accelerator and then slammed together, the total energy put into the original collision “explodes” into a shower of second-generation particles – as large as would be allowed by the totalitarian principle, which implies that if enough energy is put into a collision, every possible particle of an appropriate mass will be created.

This means that if the theorist was right in his equations, and the experimentalist applied the correct amount of energy, this new particle would by law have to have been created in the process. Now the trick is to somehow find it.

Upon the moment of this collision, very minute photographs are taken within a bubble chamber, which tracks the movements of the resulting particles (at least, as many as possible). The resulting photographs show a series of tiny streaks and loops representing these newly created particles, whose features can be measured based on how they react to magnetic fields, how long they survive before they themselves decay into even simpler particles, and numerous other very precise factors, many of which are today determined by extremely powerful computers.

All of this is so precise and so tricky, however, that the odds of the experiment revealing the particle being searched for on the first pass are extremely slim. In today’s particle accelerators, tests are performed as frequently as many times in a single second, with computers controlling the photographing and initial analysis of the collisions.

The results are filtered and only those which “seem” important to the computer are sent to human analysts to judge further. Thousands upon thousands of tests may be performed until the experimenters finally find what they are looking for.

It is clearly a somewhat tedious process, to be sure, but in the end, this is where some of the greatest discoveries in physics are made. Particle Accerators even today surely hold the key to some of the universe’s greatest and most well-kept mysteries. Surely, humanity has not yet even begun to truly understand all there is to know, and the continuing revelations of these minute particles are evidence to that fact.

References:

Asimov, I. (1966). Understanding Physics: 3 Volumes in 1. Barnes and Noble Books.

Carrigan, R. A., & Trower, W. P. (1989). Scientific American: Particle Physics in the Cosmos. New York, NY: Scientific American.

Clay, R., & Dawson, B. (1997). Cosmic Bullets - High Energy Particles in Astrophysics. Australia: Helix Books.

Lederman, L. (1993). The God Particle: If the Universe is the Answer, What is the Question? New York: Dell Publishing.