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We may not know what dark matter is, but scientists now have a better idea of what to look for.
Based on quantum gravity, physicists have developed new, much stricter upper and lower mass limits for dark matter particles. And they found that the mass range is much narrower than previously thought.
This means that dark matter candidates that are either extremely light or heavy are unlikely to be the answer, based on our current understanding of the Universe.
“This is the first time anyone has thought of using what we know about quantum gravity as a way to calculate the mass range of dark matter. We were surprised to find that no one had done this before – as were fellow scientists. our article, ”said physicist and astronomer Xavier Calmet of the University of Sussex in the UK.
“What we have done shows that dark matter can neither be ‘ultralight’ nor ‘super-heavy’ as some believe – unless some yet unknown additional force acts on it. This research helps physicists in two. means: it focuses the dark matter search area, and this will potentially also help reveal whether or not there is a mysterious additional unknown force in the Universe. “
Dark matter is undeniably one of the greatest mysteries in the universe as we know it. This is the name we give to a mysterious mass responsible for gravitational effects that cannot be explained by what we can detect by other means – normal matter like stars, dust, and galaxies.
For example, galaxies spin much faster than they should if they were simply gravitationally influenced by the normal matter they contain; the gravitational lens – the bending of space-time around massive objects – is much stronger than it should be. Anything that creates this extra gravity is beyond our ability to directly detect.
We only know it from the gravitational effect it has on other objects. Based on this effect, we know there are a lot of them. About 80% of all matter in the Universe is dark matter. It’s called dark matter because, well, it’s dark. And also mysterious.
However, we do know that dark matter interacts with gravity, so Calmet and his colleague, physicist and astronomer Folkert Kuipers at the University of Sussex, turned to the qualities of quantum gravity to try and estimate the mass range. of a hypothetical particle of dark matter (whatever).
Quantum gravity, they explain, places a number of limitations on the existence of dark matter particles of different masses. While we don’t have a decent working theory that unites the description of the gravity of general relativity with respect to space with the discrete fragment of quantum physics, we do know that any fusion of the two would reflect some fundamentals of both. . As such, dark matter particles are expected to obey quantum gravitational rules for how particles decompose or interact.
By carefully considering all of these limitations, they were able to exclude mass ranges unlikely to exist in our current understanding of physics.
Based on the assumption that only gravity can interact with dark matter, they determined that the mass of the particle should be between 10-3 electronvolts and 10seven electronvolts, depending on the spins of the particles and the nature of interactions with dark matter.
It’s incredibly smaller than the 10-24 electronvolt to 1019 traditionally attributed gigaelectronvolt range, according to researchers. And this is important, because it largely excludes some candidates, such as WIMPs (Massive Low Interaction Particles).
If such candidates later prove to be the culprits of the dark matter mystery, according to Calmet and Kuipers, it would mean that they are being influenced by a force that we do not yet know.
That would be really cool, as it would indicate new physics – a new tool for analyzing and understanding our Universe.
Importantly, the team’s constraints provide a new framework to consider in the search for dark matter, helping to narrow down where and how to look.
“As a doctoral student, it’s great to be able to work on such exciting and impactful research as this,” said Kuipers. “Our findings are very good news for experimenters because they will help them get closer to discovering the true nature of dark matter.”
The research was published in Physics Letters B.
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