A ten-meter-long magnet is designed to track the Sun in search of a particle that has never been directly detected. A total of six million euros have been allocated to build the BabyIAXO magnet system. The German Research Foundation (DFG) has approved funding for the large-scale facility, which is to be built at Deutsches Elektronen-Synchroton DESY in Hamburg. The grant application is being coordinated by Prof. Dr. Matthias Schott of the University of Bonn, an Associated Principal Investigator at the Lamarr Institute.
What an Axion Discovery Could Explain
Detecting an axion would show that the Standard Model of particle physics is incomplete and confirm the existence of a new elementary particle beyond it. If the particle proved to be the theoretically predicted QCD axion, the discovery could also resolve a decades-old puzzle: the equations of the strong interaction allow differences between matter and antimatter that experiments have not yet observed. The axion could explain why this theoretically possible CP violation is absent from the strong interaction, thereby solving the strong CP problem.
Axions could also make up some or even all of dark matter. BabyIAXO, however, is not searching directly for dark matter, but for axions that may be produced inside the Sun. A discovery would therefore not yet be proof of the composition of dark matter. However, the measured mass and interaction strength would show whether the discovered particle could be a possible building block of dark matter. They could also provide insights into how axions are produced inside the Sun and how they interact with known particles.
How the Magnet Could Make the Invisible Measurable
The same properties that make the axion scientifically compelling also make it difficult to detect. Because are expected to pass through matter almost unimpeded, a strong magnetic field and highly sensitive instruments are needed to produce even a measurable trace. BabyIAXO will point its magnet at the Sun for up to twelve hours a day, as axions may be produced inside the Sun. In the magnetic field, individual axions are expected to transform into light particles, which can then be detected by telescopes and detectors. To achieve this, the superconducting magnet is cooled to about minus 270 degrees Celsius. “This is the largest dipole magnet ever built for particle physics,” says Schott. BabyIAXO also serves as a technological precursor to the planned International Axion Observatory (IAXO), whose magnet is expected to be twice as long at 20 meters.
The search for axions is part of the Color Meets Flavor research program. This Cluster of Excellence, comprising the Universities of Bonn, Dortmund, and Siegen as well as the Jülich Research Center, investigates the interaction between the strong and weak forces and searches for previously unknown particles and forces. Schott’s research combines this experimental particle physics with modern data analysis and machine learning. As an Associated Principal Investigator at the Lamarr Institute, Schott works at the intersection of experimental particle physics, modern data analysis, and machine learning. His research group develops methods to identify rare signatures in large datasets and increase the sensitivity of physical experiments. Of the six million euros allocated for the magnet system, the DFG is providing three million, the state of North Rhine-Westphalia 2.4 million euros, and the participating universities a total of 600,000 euros.