The Parity Violating Electron Scattering (PVES) program at MESA aims to determine the weak charges of the proton and various nuclei. The ultra-high precision goal makes effects from radiative corrections, as well as hadronic and nuclear structure, non-negligible. In the latter case, the hadronic contributions can be parameterized by the electromagnetic form factors of the proton and the neutron, while similar form factor parameterizations account for the
strange quark and axial coupling contributions. The theoretical impact of these form factors and their uncertainties is studied in precision electroweak physics.

In our group, we aim to develop a systematic framework considering different theory assumptions, data sets, and experimental scenarios to quantify and minimize the theoretical uncertainty associated with the nucleon inner structure contribution in low-energy PV experiments, such as the P2 experiment at Mainz.

Precision tests are fundamental to the field of particle physics, enabling indirect probes of physics beyond the Standard Model (SM) at both high- and low-energy frontiers in a complementary fashion. Low-energy observables—measured in experiments characterized by momentum transfers below the hadronic scale, such as parity-violating electron scattering (PVES) and atomic parity violation (APV)—are particularly sensitive to deviations from the SM. This sensitivity provides a powerful avenue for exploring new physics at the multi-TeV scale.

Forthcoming experiments, such as P2 at MESA (JGU Mainz) and MOLLER at JLab, are designed to achieve unprecedented precision, with the aim of measuring low-energy observables at the per mille level. To fully realize the potential of these experimental programs, it is essential to have theoretical predictions of commensurate accuracy. Achieving this requires reliable calculations not only in the non-perturbative regime but also for higher-order radiative corrections within the perturbative framework. In particular, matching theoretical predictions to the anticipated experimental precision at the per mille level necessitates the inclusion of two-loop electroweak radiative corrections (EWRC).

It is widely recognized that the computation of two-loop EWRC for 2-to-2 processes presents significant challenges, especially when compounded by the inherent complexity of hadronic physics. In such cases, unconventional parametrizations and novel methodological approaches may be required. Our group is dedicated to advancing the calculation of two-loop EWRC relevant for experiments such as P2 and MOLLER, as well as conducting the associated phenomenological studies.

Since the discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012, no clear signs of physics beyond the Standard Model (BSM) have emerged. This motivates the hypothesis that either new physics lies at a much higher energy scale than the electroweak scale, or it couples only very weakly to the Standard Model (SM) fields. Under the assumption that BSM physics resides at a high energy scale, we can describe its low-energy effects using the Standard Model Effective Field Theory (SMEFT) framework.

SMEFT is a top-down effective field theory, where all possible higher-dimensional operators (with dimension >4) consistent with the SM symmetries are added to the SM Lagrangian. The power counting is organized according to the canonical mass dimension of operators. The leading term (dimension ≤4) recovers the SM, while higher-dimension operators parameterize BSM effects. The coefficients of these operators, known as Wilson coefficients, are not fixed by theory and must be constrained experimentally.

In our group, we investigate the phenomenology of SMEFT by studying how higher-dimensional operators modify both low- and high-energy observables in current and future experiments. We also explore how different experimental inputs can complement each other in constraining new physics through global fits to the SMEFT parameter space.