Norwegian researchers are proposing a new model to explain the ratio of dark matter to normal matter in the universe, which could be supported by measurements of cosmic microwave background radiation.
What explains why dark matter, which is essentially hypothetical, yet accepted as existent by the majority of scientists, is found in a much higher proportion in the universe than normal matter? Researchers have long been trying to answer this question, but for now, even the nature of dark matter is a mystery, and concretely proving its existence is a complex task to be solved in laboratories built deep underground and protected from cosmic radiation. The only experiment so far in which dark matter has been detected, more than once, is the DAMA project, the results of which are interpreted differently by different groups of experts.
According to the scientists participating in the program, the flashes with a frequency of seasonal variation measured with a detector containing a sodium iodide crystal are due to the collision of dark matter and the particles of the crystal. Measurements suggest that as the Solar System passes through the dark matter ring of the galaxy, at one point more dark matter particles arrive on Earth, at which point the detector also detects a significant amount of interaction. Other researchers, on the other hand, refute the theory, saying that the natural radioactivity of the objects around the laboratory or other more common factors, such as an error in the method of measurement, could explain why only one of the many dark matter experiments with such outstanding results, while the other detectors all remained silent.
The COSINE-100 project in South Korea was the latest in a series of attempts to save as much time and cost as possible to mimic the design of the DAMA experiment as accurately as possible, but the researchers were unsuccessful and unable to produce the same results.
The invisible material still doesn’t seem to reveal itself to the curious gaze.
However, the (possible) lack of practical observation does not preclude physicists from explaining on a theoretical level questions about dark matter, including why normal and dark matter are currently in the supposed proportions in the universe. According to a new theory, this is due to the presence of dark matter transforming the visible substance, which makes the particles in contact with it similar to itself. The study was published in early November by Torsten Bringmann, a professor at the University of Oslo, and his research team. in the Physical Review Letters, which presents a new model that can be said to be a version or rethink of the so-called freeze-in theory: according to this, dark matter was present only to a very small extent in addition to normal matter but later from boiling plasma. more and more invisible matter formed until its density reached its present value.
Bringmann's version modifies this in that it causes an increase in the amount of dark matter with a kind of "zombie" phenomenon:
Particles of dark matter convert the standard model particles around it to dark matter, thus their number multiplies exponentially.
The theory answers the question of how dark matter can spread rapidly in the early universe and why growth has stalled at some point. As the particles of the universe continue to travel farther and farther apart, there is also less and less opportunity for dark matter to interact with visible matter and continue its transformation.
Whether the idea holds true in practice, researchers say, can be answered by cosmic background radiation, which carries the imprint of the past and shows some form of change in the density of dark matter. In the coming times, physicians will try to support the simple, yet potentially many vague details of the theory with additional measurements, paralleling the mechanism outlined in their proposed model with the specifics of the spread of epidemics.
An earlier version of the study released on the ArXiv preprint server suggests the name pandemic dark matter to denote this type of dark matter, fitting into the line of former forbidden, cannibal, or just zombie dark matter, although these theories are freeze-out ( freeze) explanation, according to which the mass of a very large amount of dark matter in the initial times decreased over time to its current rate.
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