Seattle—University of Washington College of Arts & Sciences. When considering what makes up the universe, it’s surprising that scientists could focus on just one yes/no question. But that’s exactly what a group of researchers supported by the Heising-Simons Foundation is doing.
“Does axion dark matter exist?”
Scientists across the US are working together to determine if axions — hypothetical subatomic particles — are the leading candidate for what makes up dark matter. Although this is a big question about the universe, Heising-Simons Foundation Science Program Director Cyndi Atherton said that researchers may be able to answer it in just a few years’ time.
“It’s a small range of particle masses to investigate, relatively speaking. So we’ll look for axion dark matter in that small range, and we’ll see it – or not,” Atherton said. “Either way, we will know more about the universe.”
If the axion does not exist, researchers will consider what other types of theoretical particles could make up our universe. But if it does, Atherton said, “It will basically rewrite physics.”
Only five percent of the universe consists of normal matter that we can observe with modern instruments, she explained. The rest of the universe consists of 68 percent dark energy and 27 percent dark matter – matter that does not interact with light and that can't be observed by any current technique. If axions were the explanation for all of dark matter, we’d be able to comprehend 27 percent more – another full quarter – of the universe around us.
The Heising-Simons Foundation chose to fund this research not only because of its promise for understanding, but also because its investment is substantial enough to allow researchers to move the needle in a major area of scientific discovery. The Heising-Simons Foundation has awarded three-year grants to researchers from institutions including the following:
Lawrence Livermore National Laboratory
National Radio Astronomy Observatory/University of Virginia
University of California-Berkeley
University of Colorado-Boulder
University of Florida
University of Washington
These grants are the first investments that the Heising-Simons Foundation has made in searching for axion dark matter, and Atherton anticipates future collaborations to include more research and scientific symposia.
As leaders in the search for dark matter, The Department of Energy and National Science Foundation recently selected the University of Washington and its Department of Physics as the site for a major “Generation 2” dark-matter detector: the Axion Dark-Matter Experiment (ADMX). The ADMX program recently transitioned into a new facility at the UW Center for Experimental Nuclear Physics and Astrophysics, thereby greatly expanding the experiment infrastructure.
The new site also allows access to the facility by outside collaborations in the search for dark-matter axions, with ultimate goal of either detecting the dark-matter axion or rejecting the dark-matter axion hypothesis at high confidence. The Heising-Simons Foundation support in axion dark-matter research and development will help build up the platform for a future “Generation 3” axion search. This extension of the ADMX program will extend the axion search to nearly the entire range of plausible dark-matter axions, thereby allowing for a “definitive” search.
Gray Rybka, research assistant professor in the Department of Physics leads the development of “Generation 3” axion detection and directs the Heising-Simons supported research. The ADMX program at UW will also continue to serve as a prime research opportunity for undergraduate students in the Department of Physics. Several UW undergraduates already actively participate in this research and have made important research contributions.