The search for the mysterious dark matter, which, according to the theory, is five times more in the Universe than ordinary matter, has not yet yielded positive results, despite a lot of attempts and experiments aimed at detecting the particles that are the basis of the “dark side”. And now, researchers from the European Organization for Nuclear Research CERN in the framework of the BASE experiment (Baryon Antibaryon Symmetry Experiment) use a completely new approach, which consists in the use of another very strange substance – antimatter.
Dark matter and antimatter are the subjects of the two most important and unsolved mysteries of modern physics and astrophysics. According to astronomical observations, in the space of the Universe there is a much larger mass than the mass of matter that we can directly see. And what this mass falls into is called dark matter. We still do not know what this dark matter consists of, but there are a number of theories that explain this phenomenon, the main actors of which are exotic electrically charged particles, dark photons, superheavy gravitino and even some kind of “dark liquid” having a negative mass.
Antimatter, on the other hand, is a fairly real thing that scientists can receive and study directly. In essence, antimatter is practically the same baryonic matter, the particles of which have the opposite charge and each particle of ordinary matter has its own anti-double. And when a particle of ordinary matter collides with a particle of antimatter, they both disappear, annihilate, giving rise to an energy flash. Modern cosmological models indicate that at the time of the Big Bang, the same amount of matter and antimatter formed in the Universe, but all that we are observing now consists of ordinary matter. And this begs the question – where did all the antimatter go?
In their new research, CERN scientists began to study the possible relationship between dark matter and the existing asymmetry of the amount of matter and antimatter. To do this, they used an experiment, the essence of which is similar to the experiments conducted earlier. Usually in installations for searching for dark matter there is a certain amount of particles of ordinary matter isolated from the environment. And scientists are looking for various anomalies in the environment of these particles, which may be the results of the interaction between matter and dark matter.
However, now CERN researchers have taken a slightly different path, instead of particles of ordinary matter, they used particles of antimatter. They took the antiprotons produced by a special source and enclosed them in a device known as the Penning traps, which prevents the particles of antimatter from contacting the particles of matter. After that, the alignment of antiproton spins was carried out and these spins were controlled more than a thousand times over three months.
The idea of the experiment is to measure and calculate the average antiproton rotation frequency over a long period of time. And if something unusual happens with this frequency, this may be evidence of the interference of dark matter particles.
In particular, searches were aimed at searching for axion particles, which, as you know, are one of the main candidates for the “title” of dark matter particles. These particles are electrically neutral, they are very light and their flows pierce the space of the Universe, only occasionally interacting with both matter and antimatter. The search for traces of the interaction of axions with ordinary matter has already been inconclusive in previous experiments, and now CERN scientists have conducted similar searches involving antimatter.
However, as before, scientists were unable to detect any significant signals of the interaction of antimatter and dark matter. But such a result is not absolutely useless for science, this indicates that the interaction between antiprotons and axions does not occur at an energy level of 0.1 to 0.6 GeV, depending on the mass of axions. Such a slow and tedious exclusion of the possible ranges of masses and energies will allow scientists, in the end, to discover and study the nature of the mysterious dark matter.
Starting the experiment, CERN scientists did not really hope for clear signals. After all, receiving a signal in a given range of mass and energy would mean the existence of a huge discrepancy between the properties of matter and antimatter, which would go against almost all existing theories. And it may happen that in the future, the data collected during the BASE experiment will become a significant addition to knowledge about the relationship between matter and antimatter, dark matter and antimatter.