CDF at the cosmic frontier

The CDF results represent the worlds best limits on spin-dependent dark matter below a dark matter mass of 200 GeV/c2.

There is more than five times as much dark matter as there is visible matter in the universe, according to our current understanding. Incredibly, this dark matter completely determines the large-scale structure of the universe, forming pockets of mass that gravitationally contain clusters of galaxies. How can a particle with such a strong effect on nature be so elusive that it is able to hide in everything from galaxies to the living rooms of unaware physicists?

Many popular theories predict a relatively heavy dark matter particle of more than 100 GeV/c2. But results from several direct-detection experiments have found interesting hints of dark matter at a mass about a tenth of predicted amount. A recent paper from Fermilab theorists suggests that the Tevatron could be particularly sensitive to detecting low-mass dark matter produced from the energetic proton-antiproton collisions.

Physicists at the CDF experiment, in collaboration with the authors of the Fermilab theory paper, developed an analysis to search for dark matter based on this work. Though no evidence for dark matter was observed in this analysis, the results are impressive. The CDF search sets the world’s best limits for spin-independent dark matter at very low mass, as well as the world’s best limits for spin-dependent dark matter up to an incredible 200 GeV/c2. This novel analysis clearly demonstrates the power of collider experiments to contribute to the hunt for dark matter, even if it, unfortunately, did not find evidence for dark matter.

Experiments such as COUPP and DAMIC, along with these new results from CDF, demonstrate the formidable effort at Fermilab in hunting for the dark matter. The search continues.

Learn more

—Edited by Andy Beretvas

These physicist were responsible for this analysis. Clockwise from top left: Shalhout Z Shalhout and Robin Erbacher, both of the Unversity of California at Davis; Tom Schwarz, Fermilab; Roni Harnik, Patrick Fox and Yang Bai, all three from the Fermilab Theory Group.