An Introduction to the Standard Model of Physics

On July 4, 2012, a particle that had similar properties to the Higgs-Boson particle was discovered. With this discovery, many news articles have explained what the Higgs-Boson particle is, but not necessarily, why it is important to the field of Physics. It is with this hope that this article will help elucidate as to why the discovery of the Higgs-Boson is important to the Standard Model of Physics.

            In order to understand why the Higgs-Boson particle is important, the first thing to understand is the Standard Model of Physics. Originating in the early 1970’s, the Standard Model states that there are four fundamental forces in our universe-gravity, electromagnetism, strong force, and weak force-and that there are twelve fundamental particles from which all matter is composed of, adding up to a total of seventeen particles in all. The twelve fundamental particles, also known as fermions, are organized into two groups: quarks and leptons. There are several differences between these two groups. Quarks are always found in groups of two or three bound to one another whereas leptons on the other hand can exist independently from one another. Now for a bit of terminology: when two quarks bound together, they are known as mesons while three bound together are known as baryons. If the baryons are found in the nucleus, they are known as nucleons, otherwise they are known as hyperons. Finally, the collective name for quarks, baryons, and mesons is known as hadron.  Now, there are six quarks: up, down, charm, strange, top, and bottom. Similarly, there are six leptons: electron, electron-neutrino, muon, muon-neutrino, tau, and tau-neutrino. It should be noted that in comparison to their neutrino counterparts, the electron, muon, and tau are more massive and carry an electrical charge. These can be arranged in terms of generation. In this connotation, a generation is based on the stability of the fermion; the smaller the generational number, the higher the stability of the fermion and the lighter the fermion is as well. Generation I consists of the quarks up and down and of the electron and electron neutrino leptons. Generation II consists of the quarks charm and strange and the muon and muon-neutrino. The last generation, Generation III, consists of the quarks top and bottom and the tau and tau-neutrino leptons. Finally, fermions—both quarks and leptons-cannot occupy the same space at the same time.  In comparison, the particles that make up the four fundamental forces can occupy the same space at the same time.

            The particles that make up the fundamental forces are known as bosons. Now as aforementioned, the four fundamental forces are gravity, electromagnetism, strong, and weak forces. Each fundamental force has a corresponding boson. Before delving more into the fundamental forces and their bosons, let us look at the fundamental forces themselves. Now most of us know gravity and electromagnetism; gravity is the force that occurs when two or more masses are in range of one another that leads to attraction between the masses. Electromagnetism on the other hand is the force that results due to the interaction of electrically charged particles. It is a very large part of life—the science behind this field of physics has led to many inventions such as television, cassette tapes, radio, radar, microwaves, computers, superconductors, and other things. In fact, the light spectrum is a part of the electromagnetic spectrum. These two forces are considered infinite in range, although obviously the strength of the forces decreases the further one is from the source. The other two fundamental forces are strong and weak forces. These two forces, unlike gravity and electromagnetism, have a set range limit that is effective on the molecular scale. Weak force is the force that is responsible for radioactive decay in unstable isotopes and is behind the science of carbon dating. On the other hand, strong force is the force that is responsible for the binding of protons to neutrons in a nucleus and it binds together the quarks that form protons and neutrons. The order of strength from the strongest to the weakest force is as follows: Strong force, electromagnetic force, weak force, gravitational force. Now it should be mentioned that the Standard Model of Physics states that the forces are created from the transfer of the force carrier particles for that particular fundamental force among the fermions.

            As aforementioned, there is a corresponding boson to each of the fundamental forces. For electromagnetism, the photon is the boson or force carrier particle for the fundamental force. An easy way to remember this is the fact that photons are discrete amounts or quantized light energy. The force carrier particle for the strong force is the gluon. It should be noticed that gluons have the ability to not only bind quarks together, but also bind themselves together as well. The weak force is unique in that there are two bosons that correspond to it: the W boson and the Z boson. Now notice that I have not mentioned gravity yet. There is a reason for this; namely that gravity does not easily fit into the Standard Model of Physics paradigm. One reason for this is that gravity, being the weakest of the four fundamental forces, is easily overpowered by the other three forces.  Also, the three fundamental forces mentioned earlier have had their bosons discovered, beginning with the photon. Yet the boson for gravity, what some call the graviton, has not been discovered yet. Furthermore, there are other problems with the standard model such as: not explaining how the fermions obtain mass; not meshing up properly with the theory of general relativity; unable to explain why there is an imbalance between matter and antimatter; and unable to explain what the exact nature of dark matter and dark energy is. This is where the preliminary discovery of the Higgs-Boson particle comes in, for it could help at least verify a theory concerning how particles obtain their mass.

            The theory concerning the Higgs-Boson particle is that there lays a field throughout the universe consisting of the Higgs-Boson. When a fermion interacts with this field, it excites the field, causing the fermion to experience mass. The larger the interaction, the more mass an object has. If a particle does not interact with the field, then it is massless. One way to think of the Higgs-Boson field is like a swimming pool. If a person wades through the water, they find their movement hindered somewhat due to the viscous nature of the liquid. If the person begins to swim in the water, however, they become less hindered in comparison to simply wading through the water. In a similar vein, the particle in the first hypothetical would be much more massive than the particle in the latter one. As implied above, it is possible for a particle to be massless; the photon for example does not contain any mass. Now it should be noted that if it were confirmed that the particle discovered was the Higgs-Boson particle, this would not only help to verify the Standard Model but also give some insight as to the nature of the universe itself. Yet, even it turns out that this is not the Higgs-Boson particle, it will still raise some interesting questions into the functioning of the universe. Either way, it will be interesting to see what further developments come from the CERN labs concerning the Higgs-Boson particle.


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