© S. Ciupka

Welcome to the Research Group of Prof. U. Thoma

Welcome to our physics group at the Helmholtz-Institut für Strahlen- und Kernphysik (HISKP) in Bonn, where we are working on a better understanding of the complex bound states of the strong interaction, the hadrons.
Our main focus is on fundamental research trying to understand "Was die Welt im Innersten zusammenhält (What holds the world together at its core)" addressing questions about the fundamental composition of matter.

We mainly work in experimental particle physics, with a specific focus on the bound states of the strong interaction. The group has its focus on data analysis as well as on hardware and software development. In addition, our profile is complemented with projects related to partial wave analysis.

Latest News

11.04.2026 - The group organizes the collaboration meeting of the PANDA experiment

From 30.03.2026 to 01.04.2026 the group organized the collaboration meeting of the PANDA experiment, which was held at the University of Bonn and was attended by 50 scientists from three different countries. The main part of the event, held at the new rotation building, was made up of talks from collaboration members, who reported hardware and software progress regarding the PANDA detector systems, as well as the physics opportunities for the experiment. On Monday evening a reception was held at the FTD detector building, which included a barbecue, drinks and visits to the forward endcap EMC at the FTD mounting hall. Furthermore, tours of the universities accelerators, the Bonn cyclotron and ELSA, were organized, where attendants could visit the facilities and directly talk to staff members.

Research Areas

We are involved in the CBELSA/TAPS experiment at the electron accelerator ELSA in Bonn to investigate the spectrum and the properties of baryon resonances and in the PANDA experiment at FAIR. PANDA is under construction and will be able to investigate mesons, heavy baryons and exotic particles.  The experimental results are interpreted using the Bonn-Gatchina partial wave analysis.

Crystal Barrel
© AGThoma, C. Schmidt

CBELSA/TAPS

Experiment with the Crystal Barrel detector at ELSA in Bonn with focus on the investigation of photoproduced reactions on nucleons. The detector system covers 98% of the full angular range has been supplemented by other detector components in various setups.

PANDA experiment
© U. Kurilla

PANDA

Future experiment at FAIR which intends to do physics research on various topics from the behavior of quarks and gluons to the formation and properties of exotic particles. To collect all the necessary information from antiproton-proton collisions a versatile detector will be build.

INSIGHT-CAD.webp
© AG Thoma

INSIGHT

INSIGHT will be the successor of the CBELSA/TAPS experiment at ELSA. Many new state-of-the-art detectors across a multitude of technologies are being built as part of the excellence cluster "Color meets Flavor". AG Thoma is one of the major driving forces behind the project.

Recent Publications

B. Salisbury, C. Schmidt, T. Stockmanns, U. Thoma
"Towards an automatic geometry conversion: TGeoArbN — a ROOT-compatible triangle mesh geometry implementation",
EPJ Web of Conferences 337, 01022 (2025)

T. Seifen et al. [CBELSA/TAPS Collaboration]
"Polarization observables in double neutral pion photoproduction",
Eur. Phys. J. A 61, 173 (2025)