Research led by Jure Zupan, a theoretical physicist at the University of Cincinnati, is revisiting a long-standing question in particle physics: how to experimentally probe candidates for dark matter that have so far remained out of reach. The study suggests that nuclear fusion reactors, best known for their potential as future energy sources, could also function as laboratories for producing and studying elusive particles linked to dark matter.
Baruch, C., Fitzpatrick, P. J., Menzo, T., Soreq, Y., Trifinopoulos, S., & Zupan, J. (2025). Searching for exotic scalars at fusion reactors. Journal of High Energy Physics, 2025(10), 215. https://doi.org/10.1007/JHEP10(2025)215
The work focuses on axions and axion-like particles, hypothetical subatomic particles that arise in extensions of the Standard Model of particle physics. While axions have not yet been directly detected, they are widely considered strong candidates for dark matter, the unseen component of the universe thought to account for most of its mass.
Jure Zupan, a theoretical physicist at the University of Cincinnati stated,
“The sun is a huge object producing a lot of power. The chance of having new particles produced from the sun that would stream to Earth is larger than having them produced in fusion reactors using the same processes as in the Sun. However, one can still produce them in reactors using a different set of processes.”
Dark matter plays a central role in cosmology. Observations of galaxy rotation, gravitational lensing, and large-scale structure all point to the presence of matter that interacts gravitationally but does not emit or absorb light. Identifying its particle nature remains one of the most important open problems in physics.
In their theoretical analysis, Zupan and collaborators from Fermilab, MIT, and the Technion–Israel Institute of Technology examined whether fusion reactors could produce axions through processes distinct from those occurring in astrophysical environments. Their results indicate that under certain conditions, fusion devices could generate detectable signals of new particles.
The study considers fusion reactors that use deuterium and tritium fuel, designs that are actively being pursued in international research projects. These reactors generate large numbers of high-energy neutrons as a byproduct of fusion. According to the researchers, these neutrons can interact with materials in the reactor walls, triggering nuclear reactions that may produce exotic particles.
In addition to wall interactions, axion-like particles could also be produced when neutrons scatter and slow down, releasing energy in a process known as bremsstrahlung. These mechanisms differ from those expected in the Sun, where axions are thought to be generated primarily through interactions involving photons and charged particles in the solar plasma.
This distinction is important because earlier estimates suggested that fusion reactors would be far less effective axion sources than the Sun. The new work shows that while solar production remains dominant for some processes, reactors could access alternative channels that make laboratory-based searches feasible.
From an engineering and experimental standpoint, the proposal is notable because it reframes fusion reactors as multi-purpose facilities. Rather than serving only as energy prototypes, they could also provide controlled environments for fundamental physics experiments, complementing dedicated particle detectors and astrophysical observations.
The researchers emphasize that the work is theoretical and does not claim an imminent detection of dark matter. Instead, it outlines how future fusion facilities could be instrumented to look for rare signals associated with axions or similar particles. Any experimental implementation would require careful detector design and background suppression.
If pursued, this approach could broaden the experimental toolkit available to particle physicists. Dark matter searches currently rely on underground detectors, particle accelerators, and astronomical observations. Fusion reactors could add a new category to this list, bridging energy research and fundamental physics.
More broadly, the study illustrates how progress in one field can create opportunities in another. As fusion technology advances, its byproducts may enable experiments that address questions far beyond energy production, including the composition of the universe itself.
While many challenges remain, the idea that fusion reactors could contribute to dark matter research reflects a growing trend in science: leveraging complex, large-scale systems for multiple purposes. In this case, a device built to replicate the physics of stars on Earth may also help explain the invisible matter that shapes the cosmos.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
