dark matterthe elusive matter that makes up the majority of the mass in the universe, probably composed of massive particles called gravitons that first appeared in the first moments after big explosion.
A new theory suggests that these virtual particles may be cosmic refugees from extra dimensions.
The researchers’ calculations show that these particles can form in just the right amount to describe dark matterwhich can only be “seen” by its gravity on ordinary matter.
“Massive gravitons were generated by collisions of ordinary particles in the early universe.
This process is considered too rare for massive gravitons to be candidates for dark matter,” study co-author Giacomo Cacciaglia, a physicist at the University of Lyon in France, told Live Science.
But in a new study published in February in the journal Physical Review LetterCacciapaglia, together with Korea University physicists Haiying Cai and Seung J. Lee, discovered that enough gravitons were synthesized in the early universe to explain all the dark matter we currently find in the universe.
The study found that a graviton, if it existed, would have a mass of less than 1 megaelectronvolt (MeV), so no more than twice the mass of an electron.
This mass level is much lower than the scale where Higgs boson This results in the mass of ordinary matter – which is essential for the model to produce enough to account for all the dark matter in the universe. (For comparison, the lightest known particle is neutrinoweighs less than 2 MeV, whereas protons weigh about 940 MeV, according to National Institute of Standards and Technology.)
The team discovered this hypothetical graviton while searching for evidence of an extra dimension, which some physicists suspect exists alongside the observed three dimensions of space and the fourth dimension. time.
In team theory, when gravity It spreads through additional dimensions, and manifests in our universe as massive gravitons.
But these particles will interact weakly with ordinary matter, and only by the force of gravity.
This description is very similar to what we know about dark matter, which does not interact with light but has a gravitational effect that is felt everywhere in the universe. This gravitational effect, for example, prevents galaxies from flying away.
“The main advantage of massive gravitons as dark matter particles is that they only interact through gravity, and thus can escape attempts to detect their presence,” Kacchiapalia said.
In contrast, other dark matter candidates have been proposed – such as weak interactions of massive particles, axons, and neutrino They can also be sensed through their very subtle interactions with other powers and domains.
The fact that massive gravitons barely interact through gravity with other particles and forces in the universe offers another advantage.
“Because of their very weak interactions, they decay so slowly that they remain stable throughout the life of the universe. For the same reason, they were produced slowly during the expansion of the universe and accumulate there to this day,” Cacciapaglia said.
In the past, physicists thought gravitons were likely candidates for dark matter because the processes that produced them were so rare. As a result, gravitons will be produced at much lower levels than other particles.
But the team found that in the picoseconds (trillion seconds) after big explosionHowever, more of these gravitons could be created than previous theory suggested.
The study found that this push was enough for the massive gravitons to explain exactly how much dark matter we find in the universe.
“The gain was surprising,” said Kachiapalia. “We had to run a lot of tests to make sure the results were correct, as this resulted in a paradigm shift in the way we perceive massive gravitons as potential candidates for dark matter.”
Because massive gravitons form below the energy scale at Higgs bosonfree from the uncertainties associated with higher energy scales, which are not well explained by current particle physics.
The team’s theory connects physics learned in particle accelerators such as Big Hadron Collider With gravity physics.
This means powerful particle accelerators such as the Future Circular Collider at CERN, which will enter service in 2035, can search for evidence of potential dark matter particles.
“Probably our best shot at a future high-resolution particle collision,” said Kachiapalia. “This is something we are investigating.”
This article was originally published by life science. Read The original article is here.
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