The Standard Model of the Atom In the times of the Greeks, Democritus was smashing things. He believed that there were particles that made up matter. If something is smashed enough, it reaches a point where it can’t go any smaller. These indestructible particles are called atoms and were hypothesized to exist. Now scientists have found parts of parts of atoms which have led them to the Standard Model of the atom to help them explain these particles and their interactions. It includes all of the fundamental particles that have been found and it still being improved upon. The Standard Model is a theory that provides an explanation to the subatomic world.
There are 17 named and discovered fundamental particles. The particles in the Standard Model are categorized into 2 groups. These are fermions and bosons. Fermions are the building blocks of matter. They make up the atoms, while bosons are the forces that hold the atom together. There are 12 fermions and 5 bosons (7) (6).
Fermions have mass. These particles have a spin state of +/- 1/2. Only one fermion can occupy a space as specified by the Pauli Exclusion Principal. They all interact with gravity and the weak force. Quarks and leptons made up fermions. Quarks are subject to the strong force and therefore from hadrons. Hadrons can be baryons, which are 3 quarks together or mesons, which are 2. The quarks include, up, down, top, down, charm, and strange. Up and down are first generation quarks. They are stable and make up the nucleus of an atom. Up has a charge of +2/3 and down has a charge of -1/3. Two ups and one down make a proton while two downs and one up make a neutron. They also make more exotic composite particles as well. In mesons, they are made of one quark and an antiquark. Second generation particles are charm and strange. Charm and strange as well as the third generation particles of top and bottom decay into the first generation particles. The second and third generation particles are heavier and bigger, but aren’t stable. The up and down make up ordinary matter which is made of atoms (7)(6)(9)(2).
Leptons are not subject to the strong force. They can exist individually. The electron is a first generation lepton. The muon is the second generation and the tau is the third. They get heavier and decay faster as they increase in generation. They all have a charge of -1. Each one of these has a corresponding neutrino that is neutral. The neutrino is or nearly is massless. It is only affected by the weak force (2)(7)(6).
The force particles that hold everything together are called bosons. Bosons are the particles that apply the four fundamental forces. These forces are the strong, weak, electromagnetic, and gravity. The strong force is applied through the gluon. It holds particles together at very close distances and is strong enough to overcome the electromagnetic force. It has a spin of 1 and no mass. The gluon holds quarks together through quantum chromodynamics. There are 3 colors: blue, red, and green. Each one has an anti-color. The quarks in a hadron emit gluon with their color and an anti-color. The quark is then a different color. The gluon hits another quark in the hardon and changes its color. This is continuous and it is how the electromagnetic force is overtaken. It isn’t real color either; it’s just a way for scientists to tell them apart. When quarks in mesons begin to get space between them, the color field pulls back equally as strong. When it takes too much energy to keep them together, it takes less energy to form an antiparticle for each of them. Mass and energy are conserved by the conversion of energy to mass (9)(2).
The standard model has combined the electromagnetic and weak force into the electroweak theory. This theory states that at extremely high temperatures, like those soon after the Big Bang, the electromagnetic and weak force act the same. The electromagnetic force particle is the photon. It has no or nearly no mass and a spin of