What are elementary particles?
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What are elementary particles?

Today we know that atoms are not indivisible; they are formed by subatomic particles known as elementary particles. These can be defined as physical entities simpler than the atomic nucleus, and are considered the ultimate constituent of matter.

Atoms are not indivisible; they are formed by subatomic particles, called elementary particles

The three elementary particles that are part of the atom are the electron, the proton and the neutron. The electron has a mass of 9.11 x 10-31 kg (approximately 1/1800 of the mass of the hydrogen atom) and a negative charge of 1.602 x 10-19 C (this value is used as a unit in nuclear physics); the proton has a mass of 1.673 x 10-27 kg (approximately the mass of the hydrogen atom) and a positive charge equal in absolute value to the charge of the electron; the neutron has a slightly higher mass than the proton and lacks electric charge. Today we know that the proton and the neutron are not essentially different. They are two states of the same particle known as nucleon, so that a neutron can disintegrate into a proton plus an electron. This does not mean that the electron existed previously, but rather that it forms at the moment of the disintegration. Similarly, a proton can transform into a neutron by emitting a positive electron (positron).

Another particle of great importance in nuclear physics is the neutrino, which, although it lacks mass and charge, has energy and momentum. The existence of the neutrino was deduced from theoretical considerations that made the existence of this particle necessary if certain subatomic processes were to comply with the laws of physics.

Today we know that the proton and the neutron are not essentially different. They are two states of the same particle known as nucleon

El estudio de la radiación cósmica, así como los experimentos que se llevan a cabo en los aceleradores de partículas, han permitido comprobar la existencia de un número mucho mayor de partículas elementales, todas ellas de vida efímera, es decir, que se desintegran en otras; estas partículas han recibido los nombres de muones, tauones, mesones, hiperones, etc. El número de partículas elementales descubiertas hasta la fecha rebasa el centenar.

También se sabe que además de cada partícula existe la antipartícula correspondiente, la cual posee la misma masa que ella e igual carga pero de signo contrario. Así, el antiprotón es una partícula con la misma masa que el protón pero cuya carga es una unidad negativa; el antielectrón (que recibe el nombre de positrón) es igual que un electrón con carga positiva. Las antipartículas tienen una vida muy corta, ya que cuando se encuentran con una partícula se aniquilan liberando energía.

The study of cosmic radiation, as well as experiments conducted in particle accelerators, has made it possible to confirm the existence of a much larger number of elementary particles; all of them are short-lived, that is, they decay into others; these particles have been named muons, tauons, mesons, hyperons, etc. The number of elementary particles discovered to date exceeds one hundred.

We also know that, in addition to each particle, there exists the corresponding antiparticle, with the same mass and equal but opposite charge. Thus, the antiproton is a particle with the same mass as the proton but with a negative charge unit; the antielectron (known as positron) is the same as an electron with a positive charge. Antiparticles have a very short life, since when they encounter a particle they disintegrate releasing energy.

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