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 of dark matter particles. And they found that the range of masses is much narrower than previously thought.
This means that candidates for dark matter, which 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 for dark matter. We were surprised when we realized that no one had done it before – just like the colleagues who analyzed our work, “said physicist and astronomer Xavier Calmet of the University of Sussex in the UK.
What I have done shows that dark matter can be neither “ultra-light” nor “super-heavy”, as some people theorize – unless there is an additional yet unknown force acting on it. This research helps physicists in two ways: it focuses on the dark matter search zone, and it will also help reveal whether or not there is a mysterious force unknown in the Universe. “
Dark matter is, without a doubt, one of the greatest mysteries of the Universe as we know it. It is the name we give to a mysterious mass responsible for gravitational effects that cannot be explained by things we can detect by other means – normal matter, such as stars, dust and galaxies.
For example, galaxies rotate much faster than they should if they were only gravitationally influenced by the normal matter in them; Gravitational lenses – 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 detect directly.
We know it only by the gravitational effect it has on other objects. Based on this effect, we know that there are a lot of things out there. 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 know that dark matter interacts with gravity, so Calmet and his colleague, physicist and astronomer Folkert Kuipers of the University of Sussex, turned to the qualities of quantum gravity to try and estimate the mass range of a particle. hypothetical dark matter (whatever it is).
Quantum gravity, they explain, places a number of limits on whether dark matter particles of different masses can exist. Although we do not have a decent working theory that combines the description of the general relativity of the gravity of spatial flexibility with the discrete thickness of quantum physics, we know that any fusion of the two would reflect certain fundamental elements of both. As such, dark matter particles should follow the quantum gravitational rules of how particles decompose or interact.
By carefully accounting for all these limits, they managed to rule out mass intervals unlikely to exist under our current understanding of physics.
Based on the assumption that only gravity can interact with dark matter, they determined that the mass of particles should be between 10-3 electron volts and 107 electron volts, depending on the rotations of the particles and the nature of the interactions of dark matter.
It is extremely small than the 10-24 electronvolt at 1019 the gigaelectronvolt range is traditionally attributed, the researchers said. And this is important because it largely excludes some candidates, such as WIMP (weakly interacting massive particles).
If such candidates later find themselves guilty of the mystery of dark matter, according to Calmet and Kuipers, it would mean that they are influenced by a force we do not yet know.
It would be very interesting, because it would indicate a new physics – a new tool for the analysis and understanding of our Universe.
Above all, the constraints of the team provide a new framework to consider when looking for dark matter, helping to narrow down where and how to look.
“As a PhD student, it’s great to be able to work on research that’s as interesting and impactful as this,” Kuipers said. “Our discoveries are very good news for experimentalists, because they will help them get closer to discovering the true nature of dark matter.”
The research was published in Letters of physics B.