The standard model is a theory that displays modern ideas about the source material for building the universe. This model describes how matter is formed from its basic components, what interaction forces exist between its components.
The essence of the standard model
In their structure, all elementary particles (nucleons) that make up the atomic nucleus, like any heavy particles (hadrons), consist of even smaller simple particles called fundamental.
These primary elements of matter are currently considered quarks. The lightest and most common quarks are divided into upper (u) and lower (d). The proton consists of a combination of the quarks uud, and the neutron - udd. The charge of the u-quark is 2/3, and the d-quark has a negative charge, -1/3. If we calculate the sum of the charges of the quarks, then the charges of the proton and neutron will be strictly equal to 1 and 0. This suggests that the standard model absolutely adequately describes reality.
There are several more pairs of quarks that make up more exotic particles. So, the second pair is composed of enchanted (c) and strange (s) quarks, and the third pair is true (t) and beautiful (b).
Almost all the particles that the standard model was able to predict are already discovered experimentally.
In addition to quarks, the so-called leptons act as a “building material”. They also form three pairs of particles: an electron with an electron neutrino, a muon with a muon neutrino, and a tau lepton with a tau lepton neutrino.
Quarks and leptons, according to scientists, are the main building material on the basis of which a modern model of the Universe was created. They interact with each other using carrier particles that transmit power impulses. There are four main types of this interaction:
- strong, due to which quarks are held inside the particles;
- electromagnetic;
- weak, which leads to forms of decay;
- gravitational.
Strong color interaction is carried by particles called gluons, which lack mass and electric charge. Quantum chromodynamics studies precisely this type of interaction.
Electromagnetic interaction is carried out by the exchange of massless photons - quanta of electromagnetic radiation.
Weak interaction occurs due to massive vector bosons, which are almost 90 times more than protons.
Gravitational interaction provides the exchange of gravitons, which have no mass. True, it has not yet been possible to experimentally detect these particles.
The standard model considers the first three types of interaction as three different manifestations of a single nature. Under the influence of high temperatures, the forces that act in the Universe actually fuse together, as a result of which it is impossible to distinguish them later. The first, as scientists have discovered, combine weak nuclear interaction and electromagnetic. As a result, it creates an electroweak interaction, which we can observe in modern laboratories during the operation of particle accelerators.
The theory of the universe says that at the time of its occurrence, in the first milliseconds after the Big Bang, there was no line between electromagnetic and nuclear forces. And only after lowering the average temperature of the Universe to 10 14 K, four types of interaction were able to separate and take a modern look. In the meantime, the temperature was above this mark, only the fundamental forces of gravitational, strong and electroweak interaction acted.
Electroweak interaction is combined with strong nuclear at a temperature of about 10 27 K, which is unattainable in modern laboratory conditions. But even the Universe itself does not possess such energies now, so it is practically impossible to confirm or refute this theory. But the theory that describes the processes of combining interactions allows us to give some predictions about the processes that occur at lower energy levels. And these forecasts are now confirmed experimentally.
Thus, the standard model offers a theory of the structure of the Universe, the matter of which consists of leptons and quarks, and the types of interaction between these particles are described in theories of great unification. The model is still incomplete, because it does not include gravitational interaction. With the further development of scientific knowledge and technologies, this model can be supplemented and developed, but at present it is the best of what scientists have been able to develop.