Undergraduate students at the University of Hamburg have constructed a simple cavity detector to search for axions, hypothetical particles that may constitute dark matter. Despite limited resources, their experiment set new limits on axion properties, as detailed in a recent study. The project demonstrates that small-scale efforts can contribute to major physics challenges.
A team of students from the University of Hamburg designed and built a compact resonant cavity detector to hunt for axions. Funded by a student research grant from the university's Hub for Crossdisciplinary Learning, the project received support from the MADMAX experiment group and the Quantum Universe Cluster of Excellence, including access to a magnet and expertise. Nabil Salama, a master's student in physics and one of the authors, described it as 'the simplest version of a cavity detector for dark matter.' The setup used highly conductive materials, electronics, and measurement tools, taking advantage of existing university facilities. Agit Akgümüs, the lead author pursuing a master's in mathematical physics, noted that axions are expected to be present throughout the galaxy, allowing experiments anywhere. The students collected data but detected no axion signals. Still, their results excluded certain axion characteristics in a specific mass range, particularly those interacting strongly with photons, thus narrowing the search parameters. 'Our experiment covers only a small region, with limited sensitivity, but it still helps narrow down the possibilities,' Akgümüs said. Salama emphasized the value of scaling down complex setups: 'We reduced very complex experiments to their essential components.' The findings, published in the Journal of Cosmology and Astroparticle Physics, highlight how student-led initiatives can produce meaningful data. A peer reviewer suggested such detectors could become standard in teaching labs once axions are discovered. Salama added that their work shows these experiments are feasible on a small scale today.