What is Antiparticle - Discovery History and Simple Explanation

Literally a hundred years ago, namely in 1920, once after the principle of quantum mechanics was introduced, the subatomic world seemed extremely simple and understandable.

Indeed, according to scientists, there were only a couple of elementary particles, of which the atom consisted - a proton and a neutron (experimentally the existence of a neutron was confirmed only in the 30s).

And there is only one particle outside the atomic nucleus - an electron. But this idealistic universe did not last long.

How the first antiparticle was discovered

There is no limit to the curiosity of scientists, and therefore high-mountain laboratories began to be equipped for various scientific groups, in whose bright minds began to actively study cosmic rays, which bombard the surface of our planets.

And as a result of these studies, particles began to be discovered that, well, could not exist in the ideal proton-neutron-electron universe.

And among these open particles was the world's first antiparticle.

The world of antiparticles is essentially a mirror image of the world we are used to. After all, the mass of an antiparticle exactly coincides with the mass of an ordinary particle, only its other characteristics are completely opposite to the prototype.

Let's consider an electron. It has a negative charge, and the so-called paired particle, called a positron, has a positive charge. Accordingly, the proton has a positive charge, the antiproton has a negative charge, and so on.

So if a particle and an antiparticle collide, then they mutually annihilate, that is, the colliding particles cease to exist.

But this event does not pass without a trace. As a result of this process, a huge amount of energy is released, which is then scattered in space in the form of a stream of photons and all kinds of ultra-light particles.

Who discovered the first antiparticle

The first theoretical prediction about the existence of the notorious antiparticles was made by P. Dirac in his work, published in 1930.

So, in order to realize how particles and antiparticles manifest themselves during active interaction according to Dirac, imagine an even field.

So if you dig a small hole with a shovel, then two objects, a hole and a pile, will be formed.

If you imagine that a pile of earth is a particle, and a hole is an antiparticle, and if you fill a hole with this soil, then there will be neither one nor the other. That is, an analogue of the annihilation process will occur.

While some scientists were engaged in theoretical calculations, others assembled experimental installations. So, in particular, the experimental physicist K. D. Anderson, collected research equipment in a mining laboratory at Pike Summit (USA, Colorado) and under the leadership of R. Millikena was going to study cosmic rays.

For these purposes, an installation was invented (later the installation was called a condensation chamber), which consisted of a trap placed in a powerful magnetic field. Attacking the target, the particles flying through a special chamber left a condensation trail in it.

It was on it that scientists determined the mass of a passing particle, and depending on the angle of deflection of a particle in a magnetic field, scientists determined the particle's charge.

So, by 1932, a whole series of collisions were registered, during which particles with a mass that exactly corresponded to the mass of an electron were formed. But their deflection in a magnetic field clearly indicated that the particle had a positive charge.

This is how the antiparticle, the positron, was first discovered experimentally.

For this achievement in 1936, the scientist was awarded the Nobel Prize, which he really shared with V. F. Hess, a scientist who experimentally confirmed the existence of cosmic rays.

All subsequent antiparticles have already been obtained in laboratory experiments. Today the antiparticle is no longer something exotic and physicists can stamp them in the required amount on special accelerators.

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