An innovative experiment, aimed at exploring space in search of the mysterious substance known as dark matter, has reported its first results. The Broadband Reflector Experiment for Axion Detection (Bread) experiment, developed by the University of Chicago and the US Department of Energy’s Fermilab, has not discovered dark matter yet, but the results obtained can help scientists better understand the characteristics they can expect from such particles. Additionally, Bread has proposed a new, cost-effective method of searching for dark matter that does not require a large amount of space.
The experiment utilizes a “broadband” approach to search for hypothetical dark matter particles like “axions” and accompanying “dark photons”, covering more possibilities than other experiments, albeit with slightly lower accuracy. “If you think about it as a radio, then the search for dark matter is similar to tuning in to a certain radio station, but here we need to check a million frequencies,” explained David Miller, a scientist from the University of Chicago and co-leader of the Bread project.
Dark matter remains a major mystery for scientists, accounting for about 85% of the matter in the universe and playing a crucial role in preventing the dispersal of galaxies. However, little is known about its composition as dark matter is nearly invisible, lacking interaction with light in a way that emits or reflects ordinary photons, suggesting it is not made up of protons, neutrons, and electrons found in regular matter.
The Bread experiment involves a coaxial dish antenna in the shape of a curved metal pipe placed on a table. The goal is to detect potential axions, capture photons, and direct them to a sensor. In a full-scale experiment, the equipment will be placed in a strong magnetic field to enhance the chances of axions transforming into photons.
Preliminary results from a month-long prototype of the experiment at the University of Chicago have shown high sensitivity within the studied frequency range, paving the way for future full-scale tests. “This is just the first step in a series of exciting experiments that we have planned,” said Andrew Sonnenshain, leader of Bread and a researcher at Fermilab.
The next phase of the Bread experiment will involve moving the equipment to the magnetic facility at the National Laboratory Argonne. Institutions such as SLAC National Accelerator Laboratory, Massachusetts Institute of Technology, California Institute of Technology, and NASA’s Jet Propulsion Laboratory are collaborating with the University of Chicago and Fermilab on future iterations of Bread.
“There are numerous unresolved questions in science and a vast space for new creative ideas to address them,” concluded Miller.