Towards a Deeper Understanding of Cosmic Antinuclei

• Applicant: Dr. Maximilian Mahlein
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 575942576

The proposed research project is dedicated to investigating the properties of dark matter. Dark matter surrounds us everywhere and constitutes approximately 75% of the total mass of the universe, yet its nature remains largely unknown. In many theoretical models, dark matter can interact with itself and produce known particles in the process, including antimatter. A particularly intriguing signature of such interactions is the formation of antinuclei. These are atomic nuclei composed of antiprotons and antineutrons, which can already be studied in accelerator-based experiments on Earth. If antinuclei were produced through dark matter interactions, they would travel to Earth as part of the cosmic rays and could be detected by dedicated experiments such as AMS-02 and GAPS. Existing model predictions based on secondary processes, such as collisions of high-energy protons with the interstellar medium, expect a very low abundance of antinuclei in cosmic rays. Any contribution from dark matter processes would therefore stand out clearly in such measurements. One aim of the research proposal is to provide theoretical predictions for the flux of cosmic antinuclei through known processes. This will establish a robust reference to identify potential signals of new physics in future observations. These predictions are based on modern coalescence models that describe the formation of antinuclei from antinucleons in high-energy collisions. The models will be constrained and refined using new experimental data from the NA61/SHINE experiment at CERN, which will begin extensive measurements at lower energies in late 2025. For the first time, antinuclei will be measured with high precision at energies relevant for cosmic rays. These measurements will enable the most accurate predictions to date for the antinuclei flux in cosmic rays. In addition, the proposal includes contributions to the further development of future antimatter detectors. Particular focus is placed on balloon-borne experiments such as GAPS, whose first science flight is scheduled for December 2025. A major upgrade toward a second-generation detector, GAPS-II, is planned to follow. As part of this proposal, the potential use of scintillating fiber (SciFi) detectors will be explored. SciFi detectors are a well-established technology, successfully employed in experiments such as LHCb, and could be adapted for operation under the specific conditions of balloon-based detectors. By combining theoretical modeling, experimental validation, and technological advancement, this project will make a significant contribution to the indirect search for dark matter and to the physical characterization of naturally occurring cosmic antinuclei.

• DFG Programme: Fellowship
• International Connection: USA
• Host: Professor Dr. Philip von Doetinchem