Dark matter remains one of the great mysteries of modern physics. It is clear that it must exist, because without dark matter, for example, the motion of galaxies cannot be explained. However, dark matter was not detected in any of the experiments. Currently, there are many proposals for new experiments: they aim to detect dark matter directly through the scattering of the detection medium on the constituent atomic nuclei, namely protons and neutrons.
A team of researchers named Robert McGehee and Aaron Pearce of the University of Michigan and Gilly Elor of the Johannes Gutenberg University of Mainz in Germany have proposed a new candidate for the role of dark matter: HYPERs, or “highly interacting residual particles.”
In the HYPER model, some time after the formation of dark matter in the early universe, the strength of its interaction with ordinary matter increases sharply, making it potentially detectable today while at the same time a large amount of dark matter. case.
Since the search for heavy dark matter particles, or WIMPS, has not yet been successful, the research community is looking for alternative dark matter particles, especially lighter ones. At the same time, as a rule, phase transitions are expected in the dark sector – after all, the researchers say that there are very few of them in the visible sector. But previous studies have tended to neglect them.
“There has not been a consistent dark matter model for the mass range that some planned experiments hope to achieve. “However, our HYPER model shows that phase transition can actually help facilitate detection of dark matter,” said Elor, a doctoral student in theoretical physics at JGU.
The challenge for the corresponding model is that if dark matter interacts too strongly with normal matter, the amount (known with certainty) formed in the early universe would be very small, contradicting astrophysical observations. However, if produced in sufficient quantity, the interaction would be too weak to detect dark matter in modern experiments.
“Our main idea behind the HYPER model is that once the interaction changes dramatically, so we can have the best of both worlds: the right amount of dark matter and a massive interaction for us to detect it.”
And researchers envision it this way: In particle physics, the interaction is usually mediated by a specific particle called a mediator, and so is dark matter’s interaction with normal matter. Both the formation of dark matter and the function of its detection through this mediator depend on the strength of the interaction: the greater the mass, the weaker the interaction.
The mediator must first be heavy enough for the required amount of dark matter to be formed, and then light enough for the dark matter to be detected at all. Solution: After the formation of dark matter, a phase transition occurred where the mass of the mediator suddenly decreased.
“Thus, on the one hand, the amount of dark matter remains constant, while on the other hand, the interaction is enhanced or strengthened in such a way that dark matter can be directly detected,” said Pearce.
The new model covers almost the entire parameter range of the planned experiments.
“The HYPER dark matter model could cover almost the entire range accessible by the new experiments,” Elor said. Said.
In particular, the research team believed for the first time that the maximum cross section of mediated interaction with protons and neutrons of the atomic nucleus corresponds to astrological observations and certain decays of particle physics. The next step was to consider whether there was a dark matter model showing this interaction.
“That’s where the idea for a phase shift came up,” McGehee said. “We then calculated the amount of dark matter present in the universe and modeled the phase transition using our calculations.”
There are many constraints to consider, such as a fixed amount of dark matter.
“Here we have to systematically consider and include many scenarios, such as asking whether it is really certain whether our mediator will suddenly lead to the formation of new dark matter, which of course it shouldn’t,” Elor said. . “But in the end, we were convinced that our HYPER model was working.”
Source: Port Altele
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