Research
Belle II
The Belle II experiment at the KEK laboratory in Tsukuba, Japan, is the successor to the Belle B-factory. More than 100 institutes worldwide contribute to this collaboration, which investigates fundamental questions such as why the universe contains matter but almost no antimatter, and what constitutes dark matter. Our research focuses on flavour physics in rare B-meson decays and on searches for new, weakly interacting particles. These include dark photons that may decay into light dark matter, axion-like particles (ALPs), and long-lived particles (LLPs). My team develops the reconstruction software for the Belle II electromagnetic calorimeter and tracking detectors, and designs real-time algorithms, including machine learning methods. Further information is available at belle2.de.
(Image: © S. Takahashi)
Real-time Machine Learning
We develop real-time machine learning algorithms for track finding and calorimeter clustering in high-energy physics experiments. Our group demonstrated the first real-time deployment of graph neural networks (GNNs) for particle reconstruction, operating on FPGA-based trigger hardware with latencies below one microsecond. We evaluate different machine learning architectures, benchmark their performance on large datasets, and refine existing methods to improve accuracy and efficiency. In collaboration with international partners and industry, we translate these developments into deployable systems for detector electronics. Our work supports upgrades of the Belle II detector and contributes enabling technologies for future particle physics experiments.
LUXE
LUXE Experiment
LUXE (Laser Und XFEL Experiment) is a new project at DESY and the European XFEL that explores quantum electrodynamics (QED) under extreme conditions, where the usual methods of calculation no longer apply. In the experiment, electrons collide with a powerful laser. These conditions provide a unique opportunity to study how light and matter behave in regimes never tested before.
Our group works on the LUXE-NPOD (“New Physics at an Optical Dump”) subsystem, which uses a beam of high-energy photons created in the initial collisions to search for new, very weakly interacting particles. A particular focus is on axion-like particles (ALPs), which are candidates for physics beyond the Standard Model and may also be linked to the nature of dark matter.
Further information is available at luxe.desy.de.
(Image: © D. Nölle/DESY)
DELIGHT
The Direct search Experiment for Light dark matter (DELight) explores new detector technologies to search for dark matter with masses far below the GeV scale. The experiment uses superfluid helium-4 as an ultra clean target material. When a particle interacts in superfluid helium, the deposited energy produces quasiparticles, ultraviolet photons, and long lived excimer states. Some quasiparticles reach the liquid surface and release helium atoms through quantum evaporation. DELight detects these signals using arrays of magnetic microcalorimeters with eV scale energy resolution. The first phase of the experiment will operate a 10 liter superfluid helium target instrumented with large area microcalorimeters located both above and inside the liquid. The detector is operated at temperatures around 10 mK using a dilution refrigerator. With expected thresholds of roughly 10–20 eV, DELight will probe previously unexplored parameter space for sub GeV dark matter through nuclear scattering in helium.
More information: DELight project page.