Symmetry CP
In Physique of the particles, a theory has the symmetry CP if it is invariant under a simultaneous transformation of Charge conjugation, which exchanges particle S and Antiparticule S, and a inversion of space. Introduced after the discovery of the violation of the parity into certain reactions of radioactivity into the years 1950, it nevertheless was established into 1964 that the weak Interaction viol this symmetry.
Violation of symmetry CP
The violation of symmetry CP is one of the three requirements to explain asymmetry Matière - Antimatière observed in the Universe.
In 1964, four Physicien S American highlighted the violation of symmetry CP by studying the properties of the Kaon S neutrals, a system where these particle S mixes with their antiparticle S. Two symmetries are concerned in this process: the relation between a particle and its image in a mirror (Symmetry P), and exchanges it between particles and antiparticles (Symétrie C). The discovery rested on the observation of a particular disintegration of neutral kaons that the conservation of prohibited CP. It made it possible to conclude that the processes of exchange do not occur strictly with the same probability, as the conservation of CP would impose it.
The standard model, theory firmly established in Physical of the particles, explains this violation of symmetry CP starting from a mechanism based on the existence of three families of Quark S. This model also predicts another mechanism of violation of symmetry CP, called “direct violation”, even rarer.
See too
- theorem CPT
- chronological Baryogénèse
- Plank of microscopic physics
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