Lorentz violation in weak decays

The research focusses on theoretical aspects of testing one of the fundamental parts of contemporary (theoretical) physics: Lorentz symmetry. The significance of this symmetry has its roots in Einstein's theory of special relativity, of which it forms the basis.

There are at least two reasons for testing Lorentz symmetry. Firstly, it remains important to experimentally confirm Lorentz symmetry with growing precision because of its deep embedding in all our theories of nature. Secondly, research on new fundamental theories has brought to light the possibility of deviations from Lorentz symmetry.

The latter has led to many investigations of Lorentz symmetry over the last two decades. In particular in particle physics the issue has gained much attention. Previous to the work described in this thesis, this attention was mainly limited to a specific part of particle physics: quantum electrodynamics.

In the thesis the testing grounds for Lorentz symmetry are extended to a different important part of particle physics: the weak interaction. This interaction is relevant in nuclear reactions and for the existence of the Sun. We took mathematical steps that enable the testing of Lorentz symmetry also in the weak interaction. Subsequently we made recommendations for new experiments. In addition we confirmed, using existing experimental data, that our work gives new and unique limits on deviations from Lorentz symmetry. We also found one result that seems to suggest that Lorentz symmetry is not exact, however, this needs to be investigated further.