What is charge conjugation in particle physics?

Charge conjugation is a symmetry operation that changes particles into their antiparticles.

In particle physics, charge conjugation is a symmetry operation that transforms a particle into its antiparticle by changing its charge sign. For example, a negatively charged electron would be transformed into a positively charged positron. This operation is denoted by the symbol C.

Charge conjugation is a fundamental symmetry of the laws of physics, which means that the laws of physics are the same for particles and antiparticles. However, it is not a perfect symmetry, as some particles have different properties than their antiparticles. For example, the neutron and the antineutron have different lifetimes, even though they have the same mass and spin.

Charge conjugation is often used in combination with other symmetry operations, such as parity and time reversal, to study the behaviour of particles and antiparticles in different physical processes. These operations are collectively known as CPT symmetry, and are believed to be fundamental to the laws of physics.

In summary, charge conjugation is a symmetry operation that changes particles into their antiparticles by reversing their charge sign. It is a fundamental symmetry of the laws of physics, but is not a perfect symmetry due to differences in the properties of some particles and their antiparticles.