Mass Range for Dark Matter is Tighter than Previously Thought

Researchers have now computed the mass range for Dark Matter and found that it is tighter than what was previously considered by the scientific world.

The results of the study, which is due for publication in Physical Letters B in March 2021, absolutely narrow the range of prospective masses for Dark Matter particles, while also assisting in the quest of future Dark Matter-hunters.

The research team from the University of Sussex worked out on the lower and upper limits of the mass of Dark Matter by applying the well-known aspect that gravity acts on Dark Matter quite similar to how it acts on the visible universe.

The findings demonstrate that Dark Matter cannot be “super-heavy” or “ultra-light”, as certain researchers have proposed, unless an as-yet unexplored force also acts on it.

The researchers used the hypothesis that the only force that acts on Dark Matter is gravity, and computed that the mass of Dark Matter particles must be between 10⁻³ eV and 10⁷ eV. This range is much tighter than the 10⁻²⁴ eV to 10¹⁹ GeV spectrum that is hypothesized usually.

The fact that renders the findings much more crucial is that if the mass of Dark Matter turns out to be beyond the range estimated by the Sussex researchers, then it will also prove that an additional force—apart from gravity—acts on Dark Matter.

This is the first time that anyone has thought to use what we know about quantum gravity as a way to calculate the mass range for Dark Matter. We were surprised when we realised no-one had done it before—as were the fellow scientists reviewing our paper.

Xavier Calmet, Professor, School of Mathematical and Physical Sciences, University of Sussex

“What we’ve done shows that Dark Matter cannot be either ‘ultra-light’ or ‘super-heavy’ as some theorise—unless there is an as-yet unknown additional force acting on it. This piece of research helps physicists in two ways: it focuses the search area for Dark Matter, and it will potentially also help reveal whether or not there is a mysterious unknown additional force in the universe,” added Professor Calmet.

As a PhD student, it’s great to be able to work on research as exciting and impactful as this. Our findings are very good news for experimentalists as it will help them to get closer to discovering the true nature of Dark Matter.

Folkert Kuipers, PhD Student, University of Sussex

Kuipers works in collaboration with Professor Calmet. The visible universe—for example, the Earth and its constituents, the planets, and stars—make up 25% of all mass in the universe. Dark Matter makes up the remaining 75%.

The fact that gravity acts on Dark Matter is well-known because that is what governs the shape of galaxies.

Journal Reference:

Calmet, X & Kuipers, F (2021) Theoretical bounds on dark matter masses. Physics Letters B. doi.org/10.1016/j.physletb.2021.136068.