Speaker
Description
Gauge invariance requires physical states to be composite, even in the weak sector of the SM. The Fröhlich-Morchio-Strocchi (FMS) mechanism resolves this subtlety by predicting a one-to-one mapping between gauge and global degrees of freedom. Following the FMS framework, gauge-invariant composite operators for the Higgs, W/Z bosons, and weakly charged leptons are constructed by dressing the elementary fields with additional Higgs contributions. At leading order, these operators reduce to their perturbative expressions; beyond that, deviations due to the additional contributions are expected.
In this talk, we give an introduction to the FMS mechanism and discuss its consequences for the SM and beyond. We then investigate this mechanism on the lattice by simulating a proxy theory for the weak SM with vectorial leptons. Within this manifestly gauge-invariant setup, we show results in support of the FMS picture, including the physical spectrum of the theory and corresponding spectral densities. Finally, we present a first exploratory finite-temperature study of the theory with dynamical fermions, searching for signatures of a possible electroweak phase transition in an unquenched setting.