Is there something called antimatter

The little difference between matter and antimatter

On this picture of a bubble chamber you can see the formation of a matter and an antimatter particle.
Image: DESY

For every elementary particle there is a so-called antiparticle. It has exactly the same properties as the corresponding elementary particle, for example exactly the same mass. Its charges, however, are opposite. So the antiparticle of the negatively charged electron is the positively charged positron. When particles and antiparticles meet, they annihilate each other.

What happened during the Big Bang?

In the early development phase of our universe, the creation and destruction of particles were in equilibrium. After a few seconds, however, the universe had cooled down to such an extent that only particle-antiparticle pairs were destroyed, but no new ones were created. We can still see traces of this annihilation process today: the photons of the cosmic background radiation.

According to this notion, however, all matter and antimatter produced must have been destroyed. But now the sun, the planets and everything else in the universe consist of "normal" matter. Matter and antimatter cannot have completely annihilated each other. It is therefore assumed that in the early phase of the universe there were decays of particles that produced a little more matter than antimatter. The tiny surplus left over after the annihilation forms the entire visible matter of our universe today.

Evidence with the help of the LHC

With the help of the LHC, scientists are looking for tiny differences in the decay of matter and antimatter particles that could explain this imbalance, which in physics is known as a symmetry violation. Such a symmetry violation occurs within the framework of the Standard Model, but it cannot explain the disparity between matter and antimatter. There must therefore be another, as yet undiscovered source for the symmetry violation beyond the standard model known to us. All detectors at the LHC are looking for these additional effects.

The LHCb experiment - named after the beauty quark, in whose interactions physicists suspect evidence of the symmetry violation - will play a central role here. LHCb creates B mesons, particles that contain a beauty quark. The high-precision measurement of the decays of these B mesons could provide clues to previously unobserved symmetry-violating processes that explain how exactly one matter particle remained after the destruction of, for example, a billion matter particles with their antiparticles.