Low-energy precision observables provide key insights into possible effects beyond the Standard Model (BSM) of particle physics, complementary to searches at the energy frontier. In fact, many of our current hints for BSM contributions originate from tensions observed when confronting precise low-energy measurements with the expectations in the SM. In many cases, the precision with which possible BSM effects can be constrained, and thus the reach of the experiment, crucially depend on predictions within the SM, especially control over strong interactions. At low energies, observables in the corresponding theory, quantum chromodynamics (QCD), can no longer be approximated by expanding in its coupling, which characterizes the strength of the interaction, but instead non-perturbative methods are required. Our research aims at improved SM predictions for low-energy precision observables motivated by BSM searches at the precision frontier, based on a combination of methods including (effective) field theories, dispersion relations, and the interplay with lattice QCD. Examples for current research activities include:
- Hadronic contributions to the anomalous magnetic moment of the muon and related low-energy hadron phenomenology
- BSM searches using atomic nuclei (direct detection of dark matter, muon to electron conversion in nuclei, etc. )
- Anomalous magnetic moment of the tau from electron positron annihilation into tau anti-tau pair
