Prof. Dr. Axel Maas

The construction of non-trivial, gauge invariant asymptotic final states and initial states in electroweak scattering processes has an unexpected twist, if considering that, at sufficiently high energies, the Brout-Englert-Higgs effect becomes inoperable: They would need to be composite to maintain gauge invariance.

In fact, field theoretical considerations would imply that this is also necessary at all energies. However, there is a reason why this can be mostly safely ignored, the Fröhlich-Morchio-Strocchi mechanism. But, there may be kinematic regions in which this is not the case, e.g. at the future FCCee. There, they could yield effects which become comparable to corrections due to the strong force

After an introduction of the background, the general formalism is discussed to capture these effects, which basically boils down to augmenting Feynman rules. Some examples in toy theories, where the effect is more pronounced than in the standard model, are also presented, and compared to lattice results.