Ces différences qui sont petites, semblent être dues aux forces, appelées faibles, et qui sont par exemple resonsables des désintégrations radioactives bêta. Elles ont décelé quelques différences de comportement entre particules et antiparticules. Can they explain the disappearance of antimatter in our immediate environment?ĭes expériences en physique des particules ont monté que la symétrie n'était pas parfaite. These differences, which are small, seem to be due to the so-called weak forces, which are, for example, responsible for beta radioactive decays. Some differences in behavior between particles and antiparticles are observed. Where is it? At the far ends of the Universe? If so, under what forces?Įxperiments in particle physics have shown that the symmetry was not perfect. Obviously antimatter has left our environment. Astronomers do not observe such abnormal releases of energy. A spaceship landing on an antimatter planet would annihilate and trigger a more powerful cataclysm than most atomic bombs. The annihilation of a proton and an antiproton releases nine times the energy of a nuclear fission.

Large quantities of matter and antimatter would coexist in the same place with difficulty. Where have the antimatter particles gone? But we ares surroundes by a world of particles of matter. If this symmetry is perfect, there should be in the universe exactly the same number of particles and antiparticles. Likewise, electrons and positrons annihilate each other by destroying each other. Conversely, when an antiproton is destroyed during an annihilation reaction, ia proton pr a neutron is also destroyed. When a nucleus emits a positive antielectron, it simultaneously emits a neutrino that can be viewed as an electron without an electric charge. When an antiproton is created, so is a proton or a neutron. There is a great symmetry between matter and antimatter. The explosion generate 8 fragments, short-lived particles called mesons. The antiproton and the proton mutually destroy each other. The trajectory is interrupted by a collision with one of these protons.The collision is violent. This picture shows the trajectory of one of these antiprotons in a bubble chamber filled with liquid hydrogen whose protons are collision targets. Thus, beta radioactivity generates electrons with antineutrinos-electrons.Įnergetic antiprotons have been produced at C.E.R.N by a powerful accelarator. For example, neutrinos have antineutrinos as antiparticles. Antiprotons and antineutrons are made of antiquarks.Īll the elementary corpuscles have their corresponding in antimatter. Roday We now protons and neutrons are known to be composed of elementary corpuscles, quarks. The discovery of the antineutron in 1956 followed shortly afterwards. The energy available during a collision was greater than twice the mass energy of a proton and allowed to create an antiproton and a proton at the same time. In 1955, the antiproton was discovered in Berkeley (California) thanks to the Bevatron, a proton accelerator capable of accelrating protons to billions of electronvolts. It was the first antimatter particle to be observed in 1933 by the American physicist Carl Anderson. The antielectron - the positron - is produced in some rare radioactive decays called beta plus. The electrical current of our appliances and our lamps is a current of electrons, not of protons!Ī world built with negative protons and positive electrons would be just as plausible as ours. Electrons are light weights compared to 1800 times heavier protons. Positive protons are confined within a tiny nucleus, while negative electrons move around in an infinitely larger space. However, one can not dream of a matter less symmetrical than the matter which surrounds us! Inside our atoms, protons carrying a positive electric charge + e coexist wih electrons carrying an equal but negative charge -e.

Antimatter picture