Shedding light on darkness: A NASA image taken with the Hubble Space Telescope, shows what is inferred to be a massive ring of dark matter exerting a gravitational effect on light from the galactic cluster CL0024+17.
Credit: NASA
SYDNEY: European astrophysicists have reported on possible evidence of the elusive particles behind dark matter, controversially using data leaked from an international conference.
Dark matter is an invisible form of matter that pervades the universe. It has never been directly detected, but physicists have inferred its presence due to the gravitational pull it exerts on light.
The new research, led by astrophysicists Marco Cirelli, from the Institute of Theoretical Physics of the French Atomic Commission, in Saclay, France, and Alessandro Strumia, from the National Institute of Nuclear Physics, in Italy, has been published on the Arxiv physics website.
Sneak peak
The study has stoked controversy by citing unpublished data from the Russian-Italian PAMELA space mission, which uses a satellite observatory to study charged particles in cosmic radiation, and search for evidence of the elusive particles that are dark matter.
Cirelli and Strumia took the data via a photograph of a PowerPoint slide presented at the Identification of Dark Matter Conference held in Stockholm, Sweden, in late August, but not yet been released by the PAMELA team themselves.
The preliminary results from the image reveal an excess of unusual high-energy positrons, the antimatter counterpart to the electron (see New twist to matter-antimatter mystery, Cosmos Online).
Low-energy positrons are created naturally when ordinary matter interacts. But there is no physical environment involving ordinary matter that can explain the creation of very high-energy positrons. Since normal matter isn't the culprit, dark matter must be involved, the authors believe.
Though the results don't reveal what the dark matter particles are, they do give clues as to what kind of particles must be involved to produce the high-energy positron excess.
Cirelli and Strumia argue that the results from PAMELA fit their adjusted version of the Standard Model, a physics theory which describes the interaction of the known forces acting on all matter in the universe. The Standard Model on its own doesn't explain the existence of dark matter, and various theories have been propounded to adjust the model.
Their new 'Minimal Dark Matter' model adds the minimal amount of ingredients, without ruining the good features of the Standard Model, they said.
