A new model of dark matter proposes a new candidate for the particles that make up this mysterious form of matter, which could mean it could be detected by future experiments.
Although it makes up 85% of the matter in the universe, dark matter A shade that’s frustratingly undetectable thanks to the fact that it doesn’t seem to interact with light as well as the “ordinary” everyday matter that makes up starsplanets and us. The only way dark matter can currently be inferred is through its interactions with it gravitywith this gravitational effect literally keeping the galaxies from being torn apart as they rotate.
The new model suggests that dark matter could be made up of what its authors call Highly Interactive Particulate Relics, or HYPERs. This new model indicates that after the formation of early dark matter being, the force with which it interacts with everyday baryonic matter will suddenly increase. This HYPER model would have the result of making dark matter detectable in the current age of the universe while also providing an explanation for the abundance of dark matter.
Related: What is dark matter?
The new model was designed by PRISMA + Cluster of Excellence postdoctoral researcher Gilly Ellor, along with University of Michigan scientists Robert McGee and Aaron Pearce.
“The HYPER model of dark matter asks and answers the question: How ‘extremely active’ can light dark matter be?” McGee told Space.com. “More technically, how often might we find lighter dark matter scattering away from nuclei in direct detection experiments in the near future that are sensitive to dark matter even lighter than a proton.”
One of the current prime suspects in the search for dark matter candidates is called “Weakly interacting massive particlesor WIMPs. The fact that the search for these and other massive particles is so futile has prompted researchers to begin to suggest lighter particles such as HYPERs as dark matter candidates.
In addition, current dark matter investigations tend to neglect the idea of phase transitions, changing one physical state to another such as transitioning from a solid to a liquid, which is common in everyday matter.
Instead, the HYPER model relies on a phase transition, requiring a transition in the early universe that changes how dark matter and everyday matter interact. The team behind the HYPER model thinks this change in state could mean that dark matter may, in fact, be as detectable in the universe as it is today.
“We found that concrete models of such dark matter could be realized if a special new phase transition occurred in the early universe,” said McGee.
The “best of both worlds” for Dark Matter
The challenge for potential dark matter models currently is that if they propose that dark matter interacts strongly with baryonic matter, then the amount of dark matter that formed in the early universe would be too small to match our observations of the universe. Conversely, models that produce the right amount of dark matter suggest interactions with baryonic matter that are too weak to be detected experimentally today.
The HYPER model with its transition indicates one abrupt change in the interaction between dark matter and baryonic matter. This allows for what McGee calls “the best of both worlds” – both the right amount of dark matter to be created and a large enough interaction with everyday matter to be detectable.
interactions in Particle physics require a “medium”, which is a specific messenger particle, usually force-carrying bosons such as photons, which are messenger particles of Electromagnetic forcemoving forward.
Interactions between dark matter and ordinary matter also require a medium. The interaction strength depends on the mass of the intermediate particle, which has a greater mass, which means a weaker interaction. So the medium in this case would have to be heavy enough to create the right amount of dark matter, while still being light enough to confer detectable interaction with matter.
The aforementioned phase transition in the HYPER model sees the intermediate particle’s mass decrease abruptly as this change occurs after the formation of dark matter. This allows the inferred magnitude to be generated, while at the same time allowing for the enhanced interaction with ordinary matter that leads to scattering events that could allow dark matter to be detected directly.
While the HYPER model may address some of the challenges associated with developing a dark matter model, creating it has never been easy.
“One of the things that struck me about this research is how difficult it is to circumvent the usual limitations on dark matter,” said McGee. “When I first thought about how the phase transition could bypass the strict cosmological constraints and provide a serious benchmark for dark matter, I was very excited and naively expected to write a paper within as little as a few months’ time.
“Years later, my collaborators and I found that even this assumption of phase transition was not sufficient to guarantee protection against the many serious frontiers that any new model of dark matter must confront and overcome.”
McGee noted that if a future dark matter detection experiment sees what appears to be very light dark matter diffusing out of the cores more frequently, the HYPER model may be the only model available to physicists to explain this observation.
“That would be a very exciting circumstance for me and my co-authors,” he concluded.
The team’s research is published in the journal Physical review letters. (Opens in a new tab)
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