Nav: Home

SDU researchers present a new model for what dark matter might be

March 14, 2016

Dark matter is all around us. Though no one has ever seen it, and no one knows what it really is, indisputable physical calculations state that approximately 27% of the universe is dark matter. Only five % is the matter of which all known materials consist; from the smallest ant to the largest galaxy.

For decades, researchers have tried to detect this invisible dark matter. Several types of devices have been put up on Earth and in space to capture the particles that dark matter is supposed to consist of, and experiments have attempted to create a dark matter particle by colliding ordinary matter particles at very high temperatures.

If such a collision should one day succeed, we would however not be able to directly see the produced dark matter particle. It would immediately pass on and fly away from the detectors - but it will take some energy with it, and this energy loss will be recorded and indicate that a dark particle had been produced.

Despite all these initiatives no dark particle has yet been detected.

- Maybe it's because we have looked after dark particles in a way that will never be able to reveal them. Maybe dark matter is of a different character and needs to be looked for in a different way, says Martin Sloth, associate professor at The Centre for Cosmology and Particle Physics Phenomenology (CP3-Origins), University of Southern Denmark.

Together with his postdoc McCullen Sandora from CP3-Origins and postdoc Mathias Garny from CERN, he now presents a new model for what dark matter might be in the journal Physical Review Letters.

For decades, physicists have been working on the theory that dark matter is light and therefore interacts weakly with ordinary matter. This means that the particles are capable of being produced in colliders. This theory's dark particles are called weakly-interacting massive particles (WIMPs), and they are theorized to have been created in an inconceivably large number shortly after the birth of the universe 13.7 billion years ago.

- But since no experiments have ever seen even a trace of a WIMP, it could be that we should look for a heavier dark particle that interacts only by gravity and thus would be impossible to detect directly, says Martin Sloth.

Sloth and his colleagues call their version of such a heavy particle a PIDM particle (Planckian Interacting Dark Matter).

In their new model, they calculated how the required number of PIDM particles could have been created in the early universe.

- It was possible, if it was extremely hot. To be more precise the temperatures in the early universe must have been the highest possible in the Big Bang theory, says Sloth.

Whether this was the case or not can be tested. He explains further:

- If the universe indeed was as hot as calculated in our model, several gravitational waves from the very early childhood of the universe would have been created. We might be able to find out in the near future.

With this Sloth refers to a number of planned experiments around the world that will be able to detect signals from very early gravitational waves.

- If these experiments do not detect such signals, then our model will be falsified. Thus gravitational waves can be used to test our model, he says.

More than 10 different experiments are planned. They aim to measure the polarization of the cosmic background radiation, either from the ground or with instruments sent up in a balloon or satellite to avoid atmospheric disturbances.

Sidebar: Dark matter and dark energy

27% of the universe is believed to consist of dark matter. Dark matter is thought to be the gravitational "glue" that binds the galaxies together. No one knows what dark matter actually is.

5% the universe consists of known material such as atoms and subatomic particles.

The rest of the universe is believed to consist of dark energy. Dark energy is believed to be responsible for the current rate of the expansion of the universe.
-end-
Contact Associate Professor Martin Sloth. http://universe-origins.dk/sloth/

University of Southern Denmark

Related Dark Matter Articles:

Physicists have found a way to 'hear' dark matter
Physicists at Stockholm University and the Max Planck Institute for Physics have turned to plasmas in a proposal that could revolutionise the search for the elusive dark matter.
Cesium vapor aids in the search for dark matter
Physicists at Mainz University manage to further narrow down range of the search for dark matter
New hunt for dark matter
Dark matter is only known by its effect on massive astronomical bodies, but has yet to be directly observed or even identified.
Tracking down dark matter
Over time, scientists have developed different theories to explain exactly what the mysterious dark matter might be made of.
A new candidate for dark matter and a way to detect it
Two theoretical physicists at UC Davis have a new candidate for dark matter and a possible way to detect it.
More Dark Matter News and Dark Matter Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...